Laser processing apparatus, stack processing apparatus, and laser processing method

A laser processing apparatus and a stack processing apparatus are provided. The laser processing apparatus includes a laser oscillator and an optical system for forming a linear beam and an x-y-θ or x-θ stage. With use of the x-y-θ or x-θ stage, the object to be processed can be moved and rotated in the horizontal direction. With this operation, a desired region of the object to be processed can be efficiently irradiated with laser light, and the area occupied by a chamber provided with the x-y-θ or x-θ stage can be made small.

TECHNICAL FIELD

One embodiment of the present invention relates to a laser processing apparatus, a stack processing apparatus, and a laser processing method.

Note that one embodiment of the present invention is not limited to the above technical field. As examples of the technical field of one embodiment of the present invention, a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, an input device, an input/output device, a method for driving any of them, an apparatus for manufacturing any of them, and a method for manufacturing any of them can be given.

Note that in this specification and the like, a semiconductor device generally means a device that can function by utilizing semiconductor characteristics. A transistor, a semiconductor circuit, an arithmetic device, a memory device, and the like are each an embodiment of the semiconductor device. In addition, an imaging device, an electro-optical device, a power generation device (including a thin film solar cell, an organic thin film solar cell, and the like), and an electronic device may each include a semiconductor device.

BACKGROUND ART

A display device including a display element using a flexible substrate as a support is used for an information terminal or the like. For example, a flexible light-emitting device using an organic EL element is disclosed in Patent Document 1.

In addition, a processing apparatus that can be used for manufacturing flexible light-emitting devices and the like is disclosed in Patent Document 2.

PRIOR ART DOCUMENT

Patent Document

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

When a semiconductor element such as a transistor and a display element are formed over a flexible substrate (film), a flexible device, typified by a flexible display, can be achieved.

However, flexible substrates have lower heat resistance than glass substrates or the like, and thus, by a method in which transistors or the like are directly formed on flexible substrates, the electrical characteristics and reliability of the transistors cannot be improved in some cases.

Thus, as described in Patent Document 1, a method in which a semiconductor element, a light-emitting element, or the like formed over a glass substrate provided with a separation layer is separated and transferred to a flexible substrate has been considered. In this method, the formation temperature of the semiconductor element can be increased, and a highly reliable flexible device can be manufactured.

Furthermore, in the case where a resin is used for the separation layer, a step of reducing adhesion between the substrate and the resin by irradiation with laser light or the like is used. It is preferable that the laser light have a linear beam shape in view of the productivity.

However, a very expensive large optical component is needed to form a linear beam corresponding to the length of one side of a large glass substrate having the size of G10 (2880×3130 mm) or the like. Furthermore, as the linear beam becomes longer, it is more difficult to secure necessary energy density and thus, a laser oscillator with higher output is also needed. Accordingly, it is preferable that a linear beam that is shorter than the length of one side of the glass substrate be used and a desired region be subjected to laser irradiation several times.

Note that in the case where the beam length is shorter than the length of one side of the glass substrate, mechanisms for moving the linear beam or the glass substrate in the X and Y directions are needed, and thus there is a problem of an increase in the size of an apparatus.

Furthermore, in a manufacturing process of a flexible device, a support substrate such as the above glass substrate is used so that a transfer process, a deposition process, a lithography process, and the like are performed easily. Moreover, the above laser irradiation is performed from the support substrate side.

A laser processing apparatus that performs the above laser irradiation includes a laser oscillator and a moving stage for fixing an object to be processed. The object to be processed is subjected to laser irradiation from above the moving stage. For the moving stage, a linear movement mechanism or the like is used, and the object to be processed is moved while being irradiated with laser light, whereby a desired region of the object to be processed can be irradiated with the laser light.

However, in the case where a desired structure body can be formed over one support substrate, a laser processing apparatus that performs laser irradiation from above the object to be processed is unsuitable. In this case, it is necessary to provide the structure body on the moving stage with the structure body being on the underside. Accordingly, it is necessary to employ a structure of protecting the structure body by provision of another support substrate over the structure body or formation of a robust layer or the like over the structure body. Moreover, a step of removing the another support substrate or the robust layer is needed in some cases.

Accordingly, an object of one embodiment of the present invention is to provide a laser processing apparatus that occupies a small area. Alternatively, an object of one embodiment of the present invention is to provide a laser processing apparatus that occupies a small area and can process a large glass substrate.

Alternatively, an object is to provide a laser processing apparatus that can perform laser irradiation from below an object to be processed. Alternatively, an object is to provide a laser processing apparatus that is easily maintained. Alternatively, an object is to provide an inexpensive laser processing apparatus.

Alternatively, an object is to provide a stack processing apparatus including the above laser processing apparatus and an ashing unit. Alternatively, an object is to provide a novel stack processing apparatus. Alternatively, an object is to provide a laser processing method using the above laser processing apparatus or stack processing apparatus.

Note that the descriptions of these objects do not disturb the existence of other objects. Note that in one embodiment of the present invention, there is no need to achieve all the objects. Note that objects other than these will be apparent from the description of the specification, the drawings, the claims, and the like, and objects other than these can be derived from the description of the specification, the drawings, the claims, and the like.

Means for Solving the Problems

One embodiment of the present invention relates to a laser processing apparatus or a stack processing apparatus.

One embodiment of the present invention is a laser processing apparatus including a first movement mechanism, a second movement mechanism, a rotation mechanism, a fixing mechanism for an object to be processed, and a laser irradiation mechanism, the first movement mechanism includes a first movable portion capable of performing reciprocating linear motion in the horizontal direction, the second movement mechanism includes a second movable portion capable of performing reciprocating linear motion in the horizontal direction, the rotation mechanism includes a third movable portion having a center axis of rotation, the fixing mechanism includes a stage having a flat surface on which the object to be processed is fixed, the stage has a rectangular top surface and has a first side and a second side orthogonal to each other, the laser irradiation mechanism has a function of performing irradiation with a linear beam on the stage, the second movement mechanism is fixed to the first movable portion, the rotation mechanism is fixed to the second movable portion, the fixing mechanism is fixed to the third movable portion, the movement direction of the first movable portion and the movement direction of the second movable portion are orthogonal to each other, the center axis of the third movable portion and the center of the flat surface of the stage have an overlapping region, the length of the linear beam is approximately 1/X (X is an integer of one or more) of the length of the second side, the range of movement of the first movable portion has approximately ½ of the length of the first side, and the range of movement of the second movable portion has a length shorter than the length of the second side by approximately 1/X.

Furthermore, another embodiment of the present invention is a laser processing apparatus including a first movement mechanism, a second movement mechanism, a rotation mechanism, a fixing mechanism for an object to be processed, and a laser irradiation mechanism, the first movement mechanism includes a first movable portion capable of performing reciprocating linear motion in the horizontal direction, the second movement mechanism includes a second movable portion capable of performing reciprocating linear motion in the horizontal direction, the rotation mechanism includes a third movable portion having a center axis of rotation in the perpendicular direction, the fixing mechanism includes a stage having a flat surface to which the object to be processed is fixed, the stage has a rectangular top surface and has a first side and a second side orthogonal to each other, the laser irradiation mechanism has a function of performing irradiation with a linear beam on the stage, the second movement mechanism is fixed to the first movable portion, the rotation mechanism is fixed to the second movable portion, the fixing mechanism is fixed to the center of the third movable portion, the movement direction of the first movable portion and the movement direction of the second movable portion are orthogonal to each other, the center axis of the third movable portion and the center of the flat surface of the stage have an overlapping region, the length of the linear beam is approximately ½X (X is an integer of two or more) of the length of the first side or approximately ½X of the length of the second side, the range of movement of the first movable portion has approximately ½ of the length of the first side of the stage, and the range of movement of the second movable portion has a length shorter than the length of the first side by approximately (X+1)/2X.

Furthermore, another embodiment of the present invention is a laser processing apparatus including a movement mechanism, a rotation mechanism, a fixing mechanism for an object to be processed, and a laser irradiation mechanism, the movement mechanism includes a first movable portion capable of performing reciprocating linear motion in the horizontal direction, the rotation mechanism includes a second movable portion having a center axis of rotation in the perpendicular direction, the fixing mechanism includes a stage having a flat surface to which the object to be processed is fixed, the stage has a rectangular top surface and has a first side and a second side orthogonal to each other, the laser irradiation mechanism has a function of performing irradiation with a linear beam on the stage, the rotation mechanism is fixed to the first movable portion, the fixing mechanism is fixed to the second movable portion, the center axis of the second movable portion and the center of the flat surface of the stage have an overlapping region, the length of the linear beam is approximately ½ of the length of the first side or approximately ½ of the length of the second side, and the range of movement of the first movable portion has approximately ½ of the length of the first side.

It is preferable that the laser irradiation mechanism include a laser oscillator and that the laser oscillator emit ultraviolet light.

Furthermore, another embodiment of the present invention is a laser processing method where an object to be processed which is over a rectangle which is provided over a flat surface and has a first side having a length A and a second side having a length B is irradiated with a linear beam. The laser processing method includes a first step of setting the length of the linear beam at B/X (X is an integer of one or more); a second step of starting irradiation with the linear beam with the vicinity of a first vertex of the object to be processed serving as a starting point of processing; a third step of moving the object to be processed in the direction of the short axis of the linear beam by A/2 and then terminating the irradiation with the linear beam; a fourth step of moving the object to be processed in the direction of the long axis of the linear beam by B/X and then starting the irradiation with the linear beam; and a fifth step of moving the object to be processed in the direction opposite to that in the third step by A/2 and then terminating the irradiation with the linear beam.

Moreover, the above first to fifth steps are included, and after processing of ¼ of the area of the object to be processed is terminated, the following steps may be performed: a sixth step of rotating the object to be processed by 90°; a seventh step of setting the length of the linear beam at A/X; an eighth step of starting the irradiation with the linear beam with the vicinity of a second vertex of the object to be processed serving as a starting point of processing; a ninth step of moving the object to be processed in the direction of the short axis of the linear beam by B/2 and then terminating the irradiation with the linear beam; a tenth step of moving the object to be processed in the direction of the long axis of the linear beam by A/X and then starting the irradiation with the linear beam; and an eleventh step of moving the object to be processed in the direction opposite to that in the ninth step by B/2 and then terminating the irradiation with the linear beam.

Furthermore, another embodiment of the present invention is a laser processing method where an object to be processed which is over a rectangle which is provided over a flat surface and has a first side having a length A and a second side having a length B is irradiated with a linear beam. The laser processing method includes a first step of setting the length of the linear beam at B/2; a second step of starting irradiation with the linear beam with the vicinity of a first vertex of the object to be processed serving as a starting point of processing; a third step of moving the object to be processed in the direction of the short axis of the linear beam by A/2 and then terminating the irradiation with the linear beam; a fourth step of rotating the object to be processed by 90°; a fifth step of setting the length of the linear beam at A/2; a sixth step of starting the irradiation with the linear beam with the vicinity of a second vertex of the object to be processed serving as a starting point of processing; and a seventh step of moving the object to be processed in the direction of the short axis of the linear beam by B/2 and then terminating the irradiation with the linear beam.

Furthermore, another embodiment of the present invention is a laser processing apparatus including a first roller unit, a second roller unit, and a laser irradiation mechanism. The first roller unit and the second roller unit have an overlapping region. The laser irradiation mechanism has a function of irradiating the object to be processed provided over the first roller unit with laser light from below. The first roller unit includes a first frame, a first axis, a first roller, and a first rotation mechanism. The second roller unit includes a second frame, a second axis, a second roller, a second rotation mechanism, a third axis, a third roller, a third rotation mechanism, and a raising and lowering mechanism. The first to third rollers have a circular cylindrical shape. The first frame is provided with the first rotation mechanism. The first axis is connected to the first rotation mechanism. The first axis and the first roller have a region in which their center axes overlap with each other. The second frame is provided with the second rotation mechanism. The second axis is connected to the second rotation mechanism. The second axis and the second roller have a region in which their center axes overlap with each other. The second frame is provided with the third rotation mechanism. The third axis is connected to the third rotation mechanism. The third axis and the third roller have a region in which their center axes overlap with each other. The second frame is provided with the raising and lowering mechanism. The direction of the first axis is orthogonal to the directions of the second axis and the third axis in the horizontal direction. An optical path of the laser light is provided between the second roller and the third roller.

The laser irradiation mechanism can include a laser oscillator, a first mirror, a second mirror, a third mirror, an optical system unit, and a condenser lens. The first mirror can have a function of reflecting, in a downward direction, laser light emitted from the laser oscillator. The second mirror can have a function of reflecting laser light reflected by the first mirror to introduce it into the optical system unit. The optical system unit can have a function of extending and emitting introduced laser light. The third mirror can have a function of reflecting, in an upward direction, laser light emitted from the optical system unit. The condenser lens can have a function of condensing laser light reflected by the third mirror to form a linear beam.

The first roller unit, the second roller unit, the second mirror, the third mirror, the optical system unit, and the condenser lens can be provided in a chamber. At this time, laser light reflected by the first mirror can be introduced through a quartz window provided in the chamber.

Upper portions of the second roller and the third roller can be raised to the position higher than that of an upper portion of the first roller.

Furthermore, another embodiment of the present invention is a laser processing method in which an object to be processed is irradiated with a linear beam, using a transfer mechanism for the object to be processed; a first roller unit including a first roller capable of moving the object to be processed in an X-direction (horizontal direction); and a second roller unit including a region overlapping with the first roller unit and a second roller capable of moving the object to be processed in a Y-direction (horizontal direction) and in a Z direction (perpendicular direction). The object to be processed is placed over the transfer mechanism and transferred to predetermined X and Y positions on the first and second roller units. The second roller is raised to lift the object to be processed from the transfer mechanism. The transfer mechanism is moved outside the first and second roller units. The object to be processed is moved to a desired Y position by rotation of the second roller. The object to be processed is placed over the first roller by lowering of the second roller. The object to be processed is moved to a desired X position by rotation of the first roller. Irradiation with the linear beam is started. The object to be processed is irradiated with the linear beam while being moved in a first X-direction by rotation of the first roller. The irradiation with the linear beam is terminated. The second roller is raised to lift the object to be processed from the first roller. The object to be processed is moved to a desired Y position by rotation of the second roller. The second roller is lowered to place the object to be processed over the first roller. The irradiation with the linear beam is started. The object to be processed is irradiated with the linear beam while being moved in a second X-direction opposite to the first X-direction by rotation of the first roller. The irradiation with the linear beam is terminated. The object to be processed is moved to the predetermined X and Y positions using the first and second rollers. The second roller is raised to lift the object to be processed from the first roller. The transfer mechanism is inserted between the first roller and the object to be processed. The second roller is lowered to place the object to be processed over the transfer mechanism. The transfer mechanism is moved outside the first and second roller units to carry out the object to be processed.

The above object to be processed can include a resin and a light-transmitting substrate, and the resin can be irradiated with the linear beam through the light-transmitting substrate.

Furthermore, another embodiment of the present invention is a stack processing apparatus including the above laser processing apparatus, ashing apparatus, and a transfer apparatus.

Note that in this specification and the like, ordinal numbers such as “first” and “second” are used in order to avoid confusion among components and do not limit the components numerically.

Effect of the Invention

With the use of one embodiment of the present invention, a laser processing apparatus that occupies a small area can be provided. Alternatively, one embodiment of the present invention can provide a laser processing apparatus that occupies a small area and is capable of processing a large glass substrate.

Alternatively, a laser processing apparatus that can perform laser irradiation from below an object to be processed can be provided. Alternatively, a laser processing apparatus that is easily maintained can be provided. Alternatively, an inexpensive laser processing apparatus can be provided.

Alternatively, a stack processing apparatus including the above laser processing apparatus and an ashing unit can be provided. Alternatively, a novel stack processing apparatus can be provided. Alternatively, a laser processing method using the above laser processing apparatus or stack processing apparatus can be provided.

Note that the description of these effects does not disturb the existence of other effects. Note that one embodiment of the present invention does not necessarily achieve all the effects. Note that effects other than these will be apparent from the description of the specification, the drawings, the claims, and the like and effects other than these can be derived from the description of the specification, the drawings, the claims, and the like.

MODE FOR CARRYING OUT THE INVENTION

Embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be readily appreciated by those skilled in the art that the modes and details can be modified in various ways without departing from the spirit and the scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of embodiments below. Note that in structures of the invention described below, the same reference numerals are used, in different drawings, for the same portions or portions having similar functions, and description thereof is not repeated in some cases.

In this embodiment, a laser processing apparatus of one embodiment of the present invention will be described. Note that there is no particular limitation on the application of the laser processing apparatus, but the laser processing apparatus is particularly useful when used in a manufacturing process of a semiconductor device, a display device, a light-emitting device, a power storage device, a power generation device, or the like.

One embodiment of the present invention is a laser processing apparatus that performs irradiation of a flat-plate-like object to be processed with laser light shaped into a linear beam.

For example, the laser processing apparatus can be used for an application in which a semiconductor layer provided over a substrate is irradiated with laser light to be modified, and the like. Alternatively, it can be used for an application in which in a structure body including a resin sandwiched between two substrates, the resin is irradiated with laser light transmitted through one of the substrates to separate the one of the substrate, and the like.

The laser processing apparatus includes a laser oscillator and an optical system for forming a linear beam and an x-y-θ or x-θ stage. With the use of the x-y-θ or x-θ stage, the object to be processed can be moved and rotated in the horizontal direction. Through this operation, a desired region of the object to be processed can be efficiently irradiated with laser light, so that the area occupied by a chamber provided with the x-y-θ or x-θ stage can be made small.

FIG. 1(A)is a perspective view illustrating a laser processing apparatus of one embodiment of the present invention. A laser processing apparatus10aincludes a movement mechanism12, a movement mechanism13, a rotation mechanism14, and a fixing mechanism15for forming the x-y-θ stage in a chamber11. A laser oscillator20and an optical system unit21, a mirror22, and a lens23for forming a linear beam are also included.

FIG. 1(B) is a diagram of the x-y-θ stage seen from the horizontal direction. The movement mechanism12includes a first movable portion12b, and the movement mechanism13includes a second movable portion13b. The first movable portion12band the second movable portion13bcan perform reciprocating linear motion in the horizontal direction. As a mechanism for powering the first movable portion12band the second movable portion13b, a ball screw mechanism16or the like driven by a motor can be used, for example.

The movement mechanism13is fixed to the first movable portion12b. Thus, the movement mechanism13can perform reciprocating linear motion in the first direction (the x-direction) of the horizontal direction. Here, the movement direction of the first movable portion12band the movement direction of the second movable portion13bare set to be orthogonal to each other in the horizontal direction. Thus, when the rotation mechanism14is fixed to the second movable portion13b, the rotation mechanism14can perform a motion in the first direction and a second direction (a y-direction) orthogonal to the first direction.

The rotation mechanism14includes a third movable portion14bhaving a center axis of rotation in the perpendicular direction. The fixing mechanism15is fixed to the third movable portion14b. Thus, the fixing mechanism15can perform a motion in the rotation direction (θ-direction) in addition to the above-described first direction (the x-direction) and the second direction (the y-direction).

The fixing mechanism15includes a stage15bhaving a flat surface to which an object to be processed30is fixed. Note that the object to be processed30can be fixed onto the stage15bwith a vacuum suction mechanism or the like provided for the fixing mechanism15. Furthermore, the fixing mechanism15may include a heating mechanism as needed. Here, the center axis of the third movable portion14band the center of the flat surface of the stage15bare fixed to overlap with each other.

The stage15bhas a rectangular top surface and has a first side and a second side orthogonal to each other. For example, the first side is regarded as a long side, and the second side is regarded as a short side.

Note that although not illustrated, the fixing mechanism15includes a pusher pin and a vertical movement mechanism thereof and thus can move the object to be processed30vertically when the object to be processed30is carried out of/in the chamber11.

The laser oscillator20is preferably a pulsed laser, but may be a CW laser as long as it outputs light with a wavelength and intensity suitable for the purpose of processing. Typically, an excimer laser that emits ultraviolet light with a wavelength of 351-353 nm (XeF), a wavelength of 308 nm (XeCl), or the like can be used. Alternatively, a second harmonic wavelength (515 nm, 532 nm, or the like) or a third harmonic wavelength (343 nm, 355 nm, or the like) of a solid-state laser (a YAG laser, a fiber laser, or the like) may be used. Moreover, a plurality of laser oscillators20may be provided.

The optical system unit21includes, for example, a mirror, a beam expander, a beam homogenizer, or the like, and homogenizes and expands the in-plane distribution of the energy of laser light25emitted from the laser oscillator20. In one embodiment of the present invention, a beam shape on the processed surface of the object to be processed is a linear shape, and thus laser light26emitted from the optical system unit21is preferably shaped into a rectangle.

As the mirror22, a dielectric multilayer mirror can be used, for example, and is provided so that the incident angle of the laser light is substantially 45°. As the lens23, for example, a cylindrical lens can be used. Furthermore, a quartz window24is provided in an upper portion of the chamber11.

Note that all components other than the laser oscillator20may be provided in the chamber11. The atmosphere in the chamber11is controlled in such a structure, for example, whereby deterioration of the optical components such as the mirror or the lens can be prevented. In this case, the quartz window24is provided in a region where the laser light25enters the chamber.

Note that a glass window can be replaced with the quartz window24on the assumption that the linear beam27can have the required energy density. Moreover, the quartz window24is not necessary in the case of a structure without the chamber11.

Here, laser irradiation performed on the object to be processed30provided on the stage15bincluded in the fixing mechanism15is described.

First, the laser light25emitted from the laser oscillator20enters the optical system unit21. Laser light26that is extended and shaped into a rectangle by the optical system unit21enters the mirror22. At this time, the laser light26may be divided into a plurality of laser beams. Furthermore, although the laser light26emitted from the optical system unit21is illustrated as parallel light inFIG. 1and the like, the laser light26may be light that expands in the emission direction.

The laser light26reflected by the mirror22enters the lens23and is condensed through the quartz window24, and thus, a linear beam27is formed at a desired position of the object to be processed30. The stage15bis moved in the horizontal direction in a state where the object to be processed30is irradiated with the linear beam27as described above, whereby a desired region of the object to be processed30can be subjected to laser processing.

Here, the length of the linear beam27is ideally greater than or equal to the length of one side of the object to be processed30. In this case, only by moving the linear beam27or the object to be processed30in one horizontal direction, the entire object to be processed30can be subjected to laser processing. However, a large optical component, which is very expensive, is needed to form a linear beam corresponding to the length of one side of a large glass substrate having the size of G10 or the like.

Furthermore, as the linear beam becomes longer, it is more difficult to secure necessary energy density; therefore, a laser oscillator with higher output is also needed. Accordingly, it is practical to use a linear beam that is shorter than the length of one side of the object to be processed30and perform laser irradiation on a desired region several times. For example, as illustrated inFIG. 1, the length of the linear beam27can be approximately ¼ of the length of one side of the object to be processed30.

Note that in the case where the beam length is shorter than the length of one side of the object to be processed30, a mechanism for moving the linear beam or the object to be processed30in the x and y directions is needed, and thus there is a problem that the apparatus becomes larger.

FIGS. 2(A1) to2(A4) and2(B1) to2(B4) are conventional examples, and are diagrams illustrating methods in which the object to be processed30is irradiated with the linear beam27to form a processed region31on the entire surface (effective region). The linear beam27shows an irradiation position, and the linear beam27is fixed in the vicinity of the center of the chamber11. Furthermore, the object to be processed30can be moved by the movement mechanisms in the x and y directions.

Note that a method for irradiation of the surface of the object to be processed30with a linear beam a plurality of times will be described below. Only a desired region of the object to be processed30can be irradiated with the linear beam27in accordance with the purposes. Alternatively, irradiation of the entire surface of the object to be processed30is possible. That is, the processed regions31may be formed at intervals, and irradiation with the linear beam27may be performed to overlap with part of the processed region31.

Furthermore, the description is made on the assumption that the size of the stage15bonto which the object to be processed30is fixed is the same as the size of the object to be processed30. Note that the size of the object to be processed30may be smaller than that of the stage15b.

FIGS. 2(A1) to2(A4) illustrate an example of a case in which the linear beam27has approximately ¼ of the length of one side of the stage15b(the object to be processed30).

First, the stage15bis moved in +x direction while irradiation with the linear beam27is performed with the vicinity of a first vertex V1id of the stage15bserving as a starting point of processing (seeFIG. 2(A1)).

Next, the stage15bis moved by a distance A corresponding to the length of the first side, and then the irradiation with the linear beam27is terminated. Then, the stage15bis moved in −y direction (seeFIG. 2(A2)).

The stage15bis moved only by ¼ of a distance B corresponding to the length of the second side, and then the irradiation with the linear beam27is started. Then, the stage15bis moved in −x direction (seeFIG. 2(A3)).

Next, the stage15bis moved by the distance A, and then the irradiation with the linear beam27is terminated (seeFIG. 2(A4)). After that, operations similar to the above are performed, and the entire surface of the object to be processed30is irradiated with the linear beam27.

FIGS. 2(B1) to2(B4) illustrate an example of a case in which the linear beam27has approximately ½ of the length of the one side of the stage15b. Although the description of the basic operation is the same as the description ofFIGS. 2(A1) to2(A4), the length of the linear beam27is approximately ½ of the length of the one side of the stage15b; therefore, movement in the −y direction is needed only once, and the distance is ½ of the distance B (seeFIG. 2(B3)).

In the above conventional examples, the movement range of the first movable portion12bhas the length of the first side of the stage15bregardless of the length of the linear beam.

As described above, in the conventional examples, the entire surface of the object to be processed30is irradiated with the linear beam27by moving the stage15bin the x and y directions; therefore, the area occupied by the chamber11needs to be relatively large. In the example illustrated inFIGS. 2(A1) to2(A4), as for the inside dimension of a floor of the chamber11, the short side is approximately 7/4 times as long as the second side, the long side is approximately twice as long as the first side, and the area of the floor of the chamber11is approximately 3.8 times as large as the area of the stage15b. In the example illustrated inFIGS. 2(B1) to2(B4), as for the inside dimension of a floor of the chamber11, the short side is approximately 3/2 times as long as the second side, the long side is approximately twice as long as the first side, and the area of the floor of the chamber11is approximately 3.2 times as large as the area of the stage15b.

In one embodiment of the present invention, the movement direction of the stage15bcan be not only the conventional x and y directions but also the rotation direction (θ-direction), and the area occupied by the chamber11is made small by making one processing distance approximately ½ of the one side of the stage15b.

FIGS. 3(A) to 3(K)are diagrams illustrating operations of the laser processing apparatus10aof one embodiment of the present invention.FIGS. 3(A) to 3(K)illustrate an example of a case in which the linear beam27has approximately ¼ of the length of the one side of the stage15b.

FIGS. 3(A) to 3(K)illustrate a method in which one half surface of the object to be processed30is irradiated with laser, the object to be processed30is rotated by 180°, and the other half surface of the object to be processed30is irradiated with the laser.

First, the stage15bis moved in the +x direction while irradiation with the linear beam27is performed with the vicinity of the first vertex V1of the stage15bserving as a starting point of processing (seeFIG. 3(A)).

Next, the stage15bis moved by approximately ½ of the distance A corresponding to the length of the first side, and then the irradiation with the linear beam27is terminated. Then, the stage15bis moved in the −y direction (seeFIG. 3(B)).

The stage15bis moved only by ¼ of the distance B corresponding to the length of the second side, and then the irradiation with the linear beam27is started. Then, the stage15bis moved in the −x direction (seeFIG. 3(C)).

Next, the stage15bis moved by approximately ½ of the distance A corresponding to the length of the first side, and then the irradiation with the linear beam27is terminated. Then, the stage15bis moved in the −y direction (seeFIG. 3(D)).

Next, the stage15bis moved only by ¼ of the distance B corresponding to the length of the second side, and then the irradiation with the linear beam27is started. Then, the stage15bis moved in the +x direction (seeFIG. 3(E)).

Next, the stage15bis moved by approximately ½ of the distance A corresponding to the length of the first side, and then the irradiation with the linear beam27is terminated. Then, the stage15bis moved in the −y direction (seeFIG. 3(F)).

Next, the stage15bis moved only by ¼ of the distance B corresponding to the length of the second side, and then the irradiation with the linear beam27is started. Then, the stage15bis moved in the −x direction (seeFIG. 3(G)).

Next, the stage15bis moved by approximately ½ of the distance A corresponding to the length of the first side, and then the irradiation with the linear beam27is terminated. Then, the stage15bis moved to the center of the chamber11(seeFIG. 3(H)).

Then, the stage15bis rotated by 180°, and the stage15bis moved to the same position as that inFIG. 3(A)(seeFIGS. 3(H) and 3(I)). Hereinafter, with the vicinity of a third vertex V3of the stage15bserving as a starting point of processing, operations similar to those inFIGS. 3(A) to 3(H)are repeated, and thus the entire surface of the object to be processed30is irradiated with the linear beam27(seeFIGS. 3(J) and 3(K)).

Thus, when the length of the linear beam is ¼ of the second side of the stage15b, the movement range of the first movable portion12bis set to ½ of the length of the first side, and the movement range of the second movable portion13bis set to a length shorter than the length of the second side only by ¼, whereby the entire surface of the object to be processed30can be subjected to laser processing. In other words, when the length of the linear beam is 1/X of the second side of the stage15b, the movement range of the second movable portion13bis set to a length shorter than the length of the second side only by 1/X.

Note that each of the above movement range of the first movable portion12band the above movement range of the second movable portion13bis a minimum value, and the movement ranges may be expanded in a range of 2% or more and 20% or less than the above, preferably in a range of 5% or more and 10% or less than the above, in consideration of maintainability or a reduction in a mechanical load.

On the assumption that operations are performed in the above manner, as for the inside dimension of the floor of the chamber11, the short side can be at least approximately 3/2 times as long as the first side, and the long side can be at least approximately 7/4 times as long as the second side. At this time, the area of the floor in the chamber11is approximately 2.8 times as large as the area of the stage15b. In the conventional examples, the area of the floor in the chamber11is approximately 3.8 times. Thus, the occupation area can be significantly reduced.

Furthermore, the laser processing apparatus of one embodiment of the present invention may have a structure illustrated inFIG. 4(A). A laser processing apparatus10billustrated inFIG. 4(A)includes the same components as the laser processing apparatus10a. Note that as an operation method different from that in the laser processing apparatus10ais assumed, the movement range of the second movable portion13bincluded in the movement mechanism13can be made smaller than that in the laser processing apparatus10a. Accordingly, the inside dimension of the floor of the chamber11can be further reduced.

Moreover, as illustrated inFIGS. 4(B1) and4(B2), a variable light-blocking mechanism17that controls the length of the beam is provided in an optical path of the laser light26. Making the length of the beam variable by the light-blocking mechanism17makes it possible to deal with a case where irradiation with the linear beam27is performed in a position parallel to the first side of the object to be processed30and a case where irradiation with the linear beam27is performed in a position parallel to the second side of the object to be processed30.

The light-blocking mechanism17includes one shielding plate18on each of the right and left and can adjust the length of an opening at the center by sliding the shielding plates using a motor19as power.FIG. 4(B1) is a diagram illustrating a state where the shielding plates are slid in a direction in which the beam length is increased, and the beam length is represented as a.FIG. 4(B1) is a diagram illustrating a state where the shielding plates are slid in a direction in which the beam length is reduced, and the beam length is represented as b (a>b).

Note that althoughFIGS. 4(B1) and4(B2) each illustrate an example where the light-blocking mechanism17is provided between the optical system unit21and the mirror22(not illustrated), there is no such limitation. The light-blocking mechanism17may be provided in any region between the mirror22and the fixing mechanism15.

Note that the light-blocking mechanism17is not necessarily used in the case where laser irradiation performed to overlap with the processed region31does not cause a problem or in the case where irradiation of the outside of the object to be processed30with part of the linear beam27does not cause a problem.

FIGS. 5(A) to 5(L)are diagrams illustrating operations of the laser processing apparatus10bwhich is one embodiment of the present invention and illustrated inFIGS. 4(A) and 4(B).FIGS. 5(A) to 5(L)illustrate an example of a case in which the linear beam27has approximately ¼ of the length of the one side of the stage15b.

FIGS. 5(A) to 5(L)illustrate a method in which a first region that is ¼ of the object to be processed30is subjected to laser irradiation, the object to be processed30is rotated by 90°, and a second region that is ¼ of the object to be processed30is subjected to laser irradiation. In the method, by repetition of rotation and laser irradiation, the entire surface of the object to be processed30can be subjected to laser irradiation.

First, the stage15bis moved in the +x direction while irradiation with the linear beam27is performed with the vicinity of the first vertex V1serving as a starting point of processing (seeFIG. 5(A)). Moreover, at this time, the light-blocking mechanism17is operated such that the length of the linear beam27is approximately ¼ of a length B of the second side (seeFIG. 4(B2)).

Next, the stage15bis moved by approximately ½ of the distance A corresponding to the length of the first side, and then the irradiation with the linear beam27is terminated. Then, the stage15bis moved in the −y direction (seeFIG. 5(B)).

Next, the stage15bis moved only by ¼ of the distance B corresponding to the length of the second side, and then the irradiation with the linear beam27is started. Then, the stage15bis moved in the −x direction (seeFIG. 5(C)).

Next, the stage15bis moved by approximately ½ of the distance A corresponding to the length of the first side, and then the irradiation with the linear beam27is terminated. Then, the stage15bis moved to the center of the chamber11(seeFIG. 5(D)).

Then, the stage15bis rotated by 90°, and the stage15bis moved in the −x and +y directions such that the vicinity of a second vertex V2of the stage15bserves as a starting point of processing (seeFIGS. 5(E) and 5(F)). Moreover, at this time, the light-blocking mechanism17is operated such that the length of the linear beam27is approximately ¼ of a length A of the first side (seeFIG. 4(B1)).

Next, the stage15bis moved by approximately ½ of a distance B corresponding to the length of the second side, and then the irradiation with the linear beam27is started. Then, the stage15bis moved in the −y direction (seeFIG. 5(G)).

Next, the stage15bis moved only by ¼ of the distance A corresponding to the length of the first side, and then the irradiation with the linear beam27is started. Then, the stage15bis moved in the −x direction (seeFIG. 5(H)).

Next, the stage15bis moved by approximately ½ of the distance B corresponding to the length of the first side, and then the irradiation with the linear beam27is terminated. Then, the stage15bis moved to the center of the chamber11(seeFIG. 5(I)).

Then, the stage15bis rotated by 90°, and the stage15bis moved in the −x and +y directions such that the vicinity of the third vertex of the stage15bserves as a starting point of processing (seeFIGS. 5(J) and 5(K)). Moreover, at this time, the light-blocking mechanism17is operated such that the length of the linear beam27is approximately ¼ of the length B of the second side (seeFIG. 4(B2)).

Hereinafter, with the vicinity of the third vertex V3of the stage15bserving as a starting point of processing, operations similar to those inFIGS. 5(A) to 5(I)are repeated, and thus the entire surface of the object to be processed30is irradiated with the linear beam27(seeFIG. 5(L)).

Thus, when the length of the linear beam is ¼ of the first side of the stage15b, the movement range of the first movable portion12bis set to ½ of the length of the first side, and the movement range of the second movable portion13bis set to ¼ of the length of the first side, whereby the entire surface of the object to be processed30can be subjected to laser processing. In other words, when the length of the linear beam is ½X (X is an integer of two or more) of the first side of the stage15b, the movement range of the second movable portion13bis set to a length shorter than the length of the first side by (X+1)/2X.

Note that each of the above movement range of the first movable portion12band the above movement range of the second movable portion13bis a minimum value, and the movement ranges may be expanded in a range of 2% or more and 20% or less than the above, preferably in a range of 5% or more and 10% or less than the above, in consideration of maintainability or a reduction in a mechanical load.

On the assumption that operations are performed in the above manner, as for the inside dimension of the floor of the chamber11, the short axis can have at least a length substantially the same as that of a diagonal line of the stage15b, and the long side can have at least a length approximately 3/2 times as long as that of the first side. At this time, the area of the floor in the chamber11is approximately 2.3 times as large as the area of the stage15b. In the conventional examples, the area is approximately 3.8 times. Thus, the occupation area can be significantly reduced.

The laser processing apparatus of one embodiment of the present invention may have a structure illustrated inFIG. 6. A laser processing apparatus10cillustrated inFIG. 6has a structure based on that of the laser processing apparatus10ain the case where the beam length is approximately ½ of the stage15b. As an operation method different from that in the laser processing apparatus10ais assumed, the movement range of the second movable portion included in the movement mechanism13can be made smaller than that in the laser processing apparatus10a. Accordingly, the inside dimension of the floor of the chamber11can be further reduced.

FIGS. 7(A) to 7(J)are diagrams illustrating operations of the laser processing apparatus10cwhich is one embodiment of the present invention and illustrated inFIGS. 6(A) and 6(B).FIGS. 7(A) to 7(J)illustrate an example of a case in which the linear beam27has approximately ½ of the length of the one side of the stage15b.

FIGS. 7(A) to 7(J)illustrate a method in which the first region that is ¼ of the object to be processed30is subjected to laser irradiation, the object to be processed30is rotated by 90°, and the second region that is ¼ of the object to be processed30is subjected to laser irradiation.

In the method, by repetition of rotation and laser irradiation, the entire surface of the object to be processed30can be subjected to laser irradiation.

First, the stage15bis moved in the +x direction while irradiation with the linear beam27is performed with the vicinity of the first vertex V1of the stage15bserving as a starting point of processing (seeFIG. 7(A)).

Next, the stage15bis moved by approximately ½ of the distance A corresponding to the length of the first side, and then the irradiation with the linear beam27is terminated. Then, the stage15bis moved in the −y direction (seeFIG. 7(B)).

Next, the stage15bis moved only by ½ of the distance B corresponding to the length of the second side, and then the irradiation with the linear beam27is started. Then, the stage15bis moved in the −x direction (seeFIG. 7(C)).

Next, the stage15bis moved by approximately ½ of the distance A corresponding to the length of the first side, and then the irradiation with the linear beam27is terminated. Then, the stage15bis moved to the center of the chamber11(seeFIG. 7(D)).

Then, the stage15bis rotated by 180°, and the stage15bis moved in the −x and +y directions such that the vicinity of the third vertex V3of the stage15bserves as a starting point of processing (seeFIGS. 7(E) and 7(F)).

Hereinafter, operations similar to those inFIGS. 7(A) to 7(D)are repeated, and thus the entire surface of the object to be processed30is irradiated with the linear beam27(seeFIGS. 7(G) to 7(J)).

Thus, when the length of the linear beam is ½ of the second side of the stage15b, the movement range of the first movable portion12bis set to ½ of the length of the first side, and the movement range of the second movable portion13bis set to the length shorter than the length of the second side by ½, whereby the entire surface of the object to be processed30can be subjected to laser processing. In other words, when the length of the linear beam is 1/X of the second side of the stage15b, the movement range of the second movable portion13bis set to a length shorter than the length of the second side by 1/X.

Note that each of the above movement range of the first movable portion12band the above movement range of the second movable portion13bis a minimum value, and the movement ranges may be expanded in a range of 2% or more and 20% or less than the above, preferably in a range of 5% or more and 10% or less than the above, in consideration of maintainability or a reduction in a mechanical load.

On the assumption that operations are performed in the above manner, as for the inside dimension of the floor of the chamber11, the short side can be at least approximately 3/2 times as long as the second side, and the long side can be at least approximately 3/2 times as long as the first side. At this time, the area of the floor in the chamber11is approximately 2.4 times as large as the area of the stage15b. In the conventional example where the length of the linear beam is ½ of the second side of the stage15b(no rotation), the area of the floor in the chamber11is approximately 3.2 times. Thus, the occupation area can be significantly reduced.

Furthermore, the laser processing apparatus of one embodiment of the present invention may have a structure illustrated inFIG. 8(A). A laser processing apparatus10dillustrated inFIG. 8(A)has a structure based on that of the laser processing apparatus10bin the case where the beam length is approximately ½ of the stage15b. As an operation method different from that in the laser processing apparatus10bis assumed, a structure without the movement mechanism13can be employed. Accordingly, the inside dimension of the floor of the chamber11can be further reduced. Note that as illustrated inFIG. 8(B), the rotation mechanism14is fixed to the first movable portion12b.

Moreover, as in the laser processing apparatus10b, the light-blocking mechanism17illustrated inFIGS. 4(B1) and4(B2) is provided for the optical path of the laser light26.

FIGS. 9(A) to 9(K)are diagrams illustrating operations of the laser processing apparatus10dwhich is one embodiment of the present invention and illustrated inFIGS. 8(A) and 8(B).FIGS. 9(A) to 9(K)illustrate an example of a case in which the linear beam27is approximately ½ of the length of the one side of the stage15b.

FIGS. 9(A) to 9(K)illustrate a method in which the first region that is ¼ of the object to be processed30is subjected to laser irradiation, the object to be processed30is rotated by 90°, and the second region that is ¼ of the object to be processed30is subjected to laser irradiation. In the method, by repetition of rotation and laser irradiation, the entire surface of the object to be processed30can be subjected to laser irradiation.

First, the stage15bis moved in the +x direction while irradiation with the linear beam27is performed with the vicinity of the first vertex V1of the stage15bserving as a starting point of processing (seeFIG. 9(A)). Moreover, at this time, the light-blocking mechanism17is operated such that the length of the linear beam27is approximately ½ of the length B of the second side.

Next, the stage15bis moved by approximately ½ of the distance A corresponding to the length of the first side, and then the irradiation with the linear beam27is terminated. Then, the stage15bis moved to the center of the chamber11(seeFIG. 9(B)).

Then, the stage15bis rotated by 90°, and the stage15bis moved in the −x direction such that the vicinity of the second vertex V2of the stage15bserves as a starting point of processing (seeFIGS. 9(C) and 9(D)). Moreover, at this time, the light-blocking mechanism17is operated such that the length of the linear beam27is approximately ½ of the length A of the first side.

Next, the stage15bis moved by approximately ½ of the distance B corresponding to the length of the first side, and then the irradiation with the linear beam27is terminated. Then, the stage15bis moved to the center of the chamber11(seeFIG. 9(E)).

Then, the stage15bis rotated by 90°, and the stage15bis moved in the −x direction such that the vicinity of the third vertex V3of the stage15bserves as a starting point of processing (seeFIGS. 9(F) and 9(G)). Moreover, at this time, the light-blocking mechanism17is operated such that the length of the linear beam27is approximately ½ of the length B of the second side.

Hereinafter, operations similar to those inFIGS. 9(A) to 9(E)are repeated such that the vicinity of the third vertex V3of the stage15band the vicinity of a fourth vertex V4of the stage15bserve as starting points of processing, and thus the entire surface of the object to be processed30is irradiated with the linear beam27(seeFIGS. 9(H) to 9(K)).

Accordingly, when the length of the linear beam is ½ of the first side of the stage15b, the movement range of the first movable portion12bis ½ of the length of the first side, so that the entire surface of the stage15bcan be subjected to laser processing.

Note that the above movement range of the first movable portion12bis a minimum value, and the movement range may be expanded in a range of 2% or more and 20% or less than the above, preferably in a range of 5% or more and 10% or less than the above, in consideration of maintainability or a reduction in a mechanical load.

On the assumption that operations are performed in the above manner, as for the inside dimension of the floor of the chamber11, the short axis can have at least a length substantially the same as that of a diagonal line of the stage15b, and the long side can have at least a length approximately 3/2 times as long as that of the first side. At this time, the area of the floor in the chamber11is approximately 2.1 times as large as the area of the stage15b. In the conventional example where the length of the linear beam is ½ of the second side of the stage15b(no rotation), the area of the floor in the chamber11is approximately 3.2 times. Thus, the occupation area can be significantly reduced.

Here, the object to be processed30will be described. As illustrated inFIG. 10(A), the object to be processed30can comprise a plate-like substrate35and a structure body36provided over the substrate35. The structure body36can be directly irradiated with the linear beam27. The structure body36can be a thin film or a stack body including the thin film, for example. Specifically, as the thin film, a semiconductor film to be a semiconductor layer of a transistor and the like can be given.

Alternatively, as illustrated inFIG. 10(B), a structure including the substrate35, a substrate37, and a layer38sandwiched between the two substrates is employed. The substrate37at least laser light enter is a glass substrate or the like and is formed of a material that enables the layer38to be irradiated with the linear beam27having necessary energy density. In addition, the layer38is a layer which includes a resin layer of polyimide or the like, for example, and in which the resin layer can be processed by being irradiated with the linear beam27having a given intensity or higher.

The resin layer is provided in contact with an entire surface of the substrate37. Alternatively, it may be provided partly in contact with the substrate37. By laser processing of the resin layer, the adhesion between the resin layer and the substrate37is decreased, so that the layer38and the substrate37which are supported by the substrate35can be separated from each other.

Alternatively, as illustrated inFIG. 10(C), the object to be processed30can have a structure excluding the substrate35from the structure inFIG. 10(B). In this case, the layer38loses the support substrate after processing of the object to be processed30, and therefore, it is preferable to use an auxiliary jig40illustrated inFIG. 11(A).

The auxiliary jig40includes a frame41and a suction portion42. A notch for mounting the object to be processed30is provided in the frame41. The frame41can be formed using, for example, a metal or a composite material of a metal and a ceramic, and the suction portion42can be formed using a breathable porous ceramic or the like. Note that althoughFIG. 11(A)illustrates an example where four suction portions42are provided in the notch, the number of the suction portions42is not limited.

FIG. 11(B)is a cross-sectional view taken along X1-X2illustrated inFIG. 11(A). In the notch of the auxiliary jig40, a structure without a step between the frame41and the suction portions42on both of the front and back is employed.

FIG. 11(C)is a diagram illustrating a state in which the auxiliary jig40on which the object to be processed30is mounted is fixed to the fixing mechanism15. Moreover,FIG. 11(D)is a cross-sectional view taken along X3-X4illustrated inFIG. 11(C).

An opening43reaching the surface of the stage15bis provided in the fixing mechanism15and a vacuum pump or the like is connected to the opening43, whereby an object in contact with the surface of the stage15bcan be subjected to vacuum suction. Here, the auxiliary jig40is provided over the stage15bso that the opening43is in contact with the suction portion42and the frame41. When the auxiliary jig40is provided in this manner, the object to be processed30can be vacuum-sucked through the suction portion42together with the auxiliary jig.

With the use of the auxiliary jig40, laser processing can be performed without detachment of the layer38even when the object to be processed30has a mode illustrated inFIG. 10(C).

Furthermore, althoughFIG. 1and the like illustrate an example in which the mirror22is provided so that an incident angle of the laser light26is approximately 45° as illustrated inFIG. 12(A), the incident angle of the laser light26with respect to the mirror22may be an angle smaller than 45° as illustrated inFIG. 12(B). For example, the incident angle is larger than or equal to 20° and smaller than or equal to 45°, preferably larger than or equal to 25° and smaller than or equal to 40, further preferably larger than or equal to 30° and smaller than or equal to 40.

Alternatively, as illustrated inFIG. 12(C), the incident angle of the laser light26with respect to the mirror22may be an angle larger than 45°. For example, the incident angle is larger than 45° and smaller than or equal to 70°, preferably larger than or equal to 50° and smaller than or equal to 65°, further preferably larger than or equal to 50° and smaller than or equal to 60°.

The incident angle of the laser light26with respect to the mirror22is changed as illustrated inFIGS. 12(A) to 12(C), whereby the object to be processed30can be obliquely irradiated with the linear beam27. Therefore, when the object to be processed30has a structure illustrated inFIG. 10(B), and the layer38is irradiated with the linear beam through the substrate37, for example, processing defect due to a foreign substance over the substrate37can be suppressed. Furthermore, it is more effective to perform processing at the above angle.

As a laser irradiation method in this case, the object to be processed30is irradiated with the linear beam in any two of the modes illustrated inFIGS. 12(A) to 12(C). For example, any one of the modes illustrated inFIGS. 12(A) to 12(C)is selected to perform first laser irradiation on the object to be processed30, and the mode other than the mode selected for the first laser irradiation is selected to perform second laser irradiation on the region that has been irradiated.

Note that the incident angle of the laser light26with respect to the mirror22can be easily changed by change of the angle of the mirror22. For example, as illustrated inFIGS. 12(A) to 12(C), a jig28provided for the mirror22may be rotated with a motor29. At this time, a mechanism for vertical moving of the object to be processed30may be used such that a focal point of the linear beam27is formed in a desired region.

In the case where the object to be processed30has the mode illustrated inFIG. 10(B)orFIG. 10(C)and the resin is subjected to laser processing, a step of removing the resin is included in the subsequent process in many cases. In such a case, it is preferable to use a stack processing apparatus in which the laser processing apparatus of one embodiment of the present invention and a plasma treatment apparatus for removing a resin (e.g., an ashing apparatus) are combined.

FIG. 13is a diagram illustrating an example of the above stack processing apparatus. A stack processing apparatus10eincludes a laser processing apparatus, a transfer chamber51, a load/unload chamber52, an unload chamber53, and a plasma treatment chamber54. Note that each chamber is simply illustrated with a gate valve and the like omitted inFIG. 13.

AlthoughFIG. 13exemplifies the structure illustrated inFIG. 1as a laser processing apparatus, a structure inFIG. 4,FIG. 6, orFIG. 8may be employed. Note that a structure excluding the plasma treatment chamber54from the structure illustrated inFIG. 13can be also employed as the stack processing apparatus10e. Alternatively, a structure excluding the unload chamber53from the stack processing apparatus10ecan be also employed.

The transfer chamber51includes a transfer mechanism60and a member can be carried out of/in each chamber before and after processing.

As illustrated inFIG. 14(A), the transfer mechanism60is an arm-type robot and includes a raising and lowering mechanism61, a joint mechanism62, arms63and64, a reversal mechanism65, a fork66, and the like. The object to be processed30and the like can be transferred by a telescopic operation of the arms63and64using the joint mechanism62or the like as an axis, an upward/downward operation of the raising and lowering mechanism61, and the like.

The reversal mechanism65includes a support portion65aand a rotation portion65b. As illustrated inFIG. 14(B), the fork66can be rotated by rotation of the rotation portion65b.

Furthermore, the object to be processed30or the like is supported by the fork66with an adsorption mechanism67. Thus, as illustrated inFIGS. 14(B) and 14(C), the object to be processed30and the like can be supported even in a state where the fork66is inclined and reversed. Note that as the adsorption mechanism67, a vacuum suction mechanism can be used, for example. Furthermore, the adsorption mechanism67may have a sucker.

The load/unload chamber52includes a cassette45aand can store the object to be processed30. In addition, a member30cthat has been processed and has been carried out of the plasma treatment chamber54can be stored in the cassette45a.

The unload chamber53includes a cassette45band can store a member30athat has been processed and has been carried out of the chamber11of the laser processing apparatus. Note that the member30amay be stored in the cassette45a, and the member30cmay be stored in the cassette45b.

The plasma treatment chamber54is provided with a down-flow ashing unit including a plasma generation mechanism47, a shower plate48, and a stage49, and the like. A gas line for supplying oxygen, a rare gas, and the like, a high-frequency power source, and the like are connected to the plasma generation mechanism47, and an oxygen radical can be generated. For example, the object to be processed30with the resin exposed on its surface is set on the stage49, and an oxygen radical and carbon included in the resin are reacted with each other, whereby the resin can be vaporized and removed.

The shower plate48can suppress spread of plasma by being supplied with a ground potential. With the use of the shower plate48, plasma damage to the object to be processed30can be suppressed without disruption of useful supply of an oxygen radical. The stage49may be provided with a heater for promoting the above reaction.

Here, an example of a process using the stack processing apparatus10ewill be briefly described. Note that the object to be processed30has the mode illustrated inFIG. 10(B), and the purpose is laser processing of the resin sandwiched between the substrate35and the substrate37and removal thereof by ashing.

First, the cassette45awhere the object to be processed30is stored is set in the load/unload chamber52, and the object to be processed30is transferred to the chamber11of the laser processing apparatus by the transfer mechanism60.

After termination of the laser processing, the member30a(e.g., the substrate37or the like illustrated inFIG. 10(B)) separated from the object to be processed30is carried out of the chamber11by the transfer mechanism60and stored in the cassette45bof the unload chamber53. Note that the member30acan be separated from the object to be processed30in the following manner: the fork66of the transfer mechanism60is reversed, a surface of the member30ais adsorbed by the adsorption mechanism67, and the member30ais lifted above by the raising and lowering mechanism61.

Next, the member30bobtained by separation of the member30afrom the object to be processed30is carried out of the chamber11by the transfer mechanism60and transferred to the plasma treatment chamber54. Then, ashing treatment is started. A multitasking operation in which a new object to be processed30is subjected to laser processing treatment during the ashing treatment may be performed.

After the termination of the ashing treatment, the member30cthat has been subjected to treatment is carried out of the plasma treatment chamber54by the transfer mechanism60and stored in the cassette45aof the load/unload chamber52.

As described above, the object to be processed30can be subjected to the laser processing and the ashing treatment successively. Furthermore, the treatment time can be shortened by the multitasking operation.

In this embodiment, a laser processing apparatus different from that in Embodiment 1 will be described. Note that although there is no limitation on the usage of the laser processing apparatus, the laser processing apparatus is particularly useful in a manufacturing process of a semiconductor device, a display device, a light-emitting device, a power storage device, a power generation device, or the like.

One embodiment of the present invention is a laser processing apparatus that performs irradiation of a flat-plate-like object to be processed with laser light shaped into a linear beam. For example, the laser processing apparatus can be used for an application in which a semiconductor layer provided over a support substrate is irradiated with laser light to be modified, and the like. Alternatively, it can be used for an application in which in a structure body including a resin formed over a support substrate, the resin is irradiated with laser light transmitted through the support substrate and processed to separate the support substrate, and the like.

The laser processing apparatus includes a laser oscillator and an optical system for forming a linear beam, a first roller unit, and a second roller unit.

The first roller unit has a function of moving the object to be processed in a first horizontal direction (X-direction). The second roller unit has a function of moving the object to be processed in a second horizontal direction (Y-direction) and a perpendicular direction (Z-direction). Moreover, the laser irradiation mechanism has a function of irradiating the object to be processed provided over the first roller unit with laser light from below.

Therefore, in the laser processing apparatus of one embodiment of the present invention, laser irradiation of the structure body formed over the support substrate from the support substrate side can be easily performed. In the conventional laser processing apparatus that performs laser irradiation from above the object to be processed, another support substrate or the like needs to be provided over the structure body. Furthermore, a step of removing the another support substrate or the like is also necessary.

FIG. 15(A)is a perspective view illustrating a laser processing apparatus of one embodiment of the present invention. The laser processing apparatus510aincludes a laser irradiation mechanism for forming a linear beam. Furthermore, a first roller unit540and a second roller unit550are included in a chamber511, and the both are provided to have an overlapping region. An object to be processed530is provided over the first roller unit540.

FIG. 15(B)is a diagram illustrating the laser irradiation mechanism. The laser irradiation mechanism includes a laser oscillator520, a mirror523a, a mirror523b, a mirror523c, an optical system unit521, and a lens522.

The laser oscillator520is preferably a pulsed laser, but may be a CW laser as long as it outputs light with a wavelength and intensity suitable for the purpose of processing. Typically, an excimer laser that emits ultraviolet light with a wavelength of 351-353 nm (XeF), a wavelength of 308 nm (XeCl), or the like can be used. Alternatively, a second harmonic wavelength (515 nm, 532 nm, or the like) or a third harmonic wavelength (343 nm, 355 nm, or the like) of a solid-state laser (a YAG laser, a fiber laser, or the like) may be used. Moreover, a plurality of laser oscillators520may be provided.

As each of the mirror523a, the mirror523b, and the mirror523c, a dielectric multilayer mirror can be used, for example, and is provided so that the incident angle of the laser light entering each mirror is substantially 45°.

The optical system unit521includes, for example, a mirror, a beam expander, a beam homogenizer, and the like, and homogenizes and expands the in-plane distribution of the energy of laser light525emitted from the laser oscillator520. In one embodiment of the present invention, a beam shape on the processed surface of the object to be processed is a linear shape, and thus laser light526emitted from the optical system unit521is preferably shaped into a rectangle.

The lens522is a condensing lens, and a cylindrical lens can be used, for example.

As illustrated inFIG. 15(A), all the components excluding the laser oscillator520and the mirror523aare preferably provided in the chamber511. The atmosphere in the chamber511is controlled in such a structure, for example, whereby deterioration of the optical components such as the mirror or the lens can be prevented, leading to easy maintenance. In this case, a quartz window524is provided in a region where the laser light525enters the chamber511.

Note that a glass window can be replaced with the quartz window524on the assumption that the linear beam527can have the required energy density. Moreover, the quartz window524is not necessary in the case of a structure without the chamber511.

Here, laser irradiation of the object to be processed530provided over the first roller unit540will be described.

First, the laser light525output from the laser oscillator520in the horizontal direction enters the mirror523aand is reflected in the downward direction. Then, the laser light525is reflected by the mirror523band enters the optical system unit521.

The laser light526that is extended and shaped into a rectangle by the optical system unit521enters the mirror523c. At this time, the laser light526may be divided into a plurality of laser beams. Furthermore, although the laser light526emitted from the optical system unit521is illustrated as parallel light inFIG. 15(B), the laser light526may be light that expands in the emission direction.

The laser light526reflected by the mirror523centers the lens522, and thus the linear beam527is formed at a desired position of the object to be processed530. The object to be processed530is moved in the horizontal direction while being irradiated with the linear beam527formed in this manner, whereby a desired region of the object to be processed530can be subjected to laser processing.

FIG. 16(A)is a perspective view illustrating the first roller unit540. Furthermore,FIG. 16(B)is a top view of the first roller unit540, a cross-sectional view taken along X1-X2in the top view, and a cross-sectional view taken along Y1-Y2in the top view. The first roller unit540includes a plurality of frames541, a plurality of rollers542, a plurality of rotation axes543, and a plurality of rotation mechanisms544. In the laser processing apparatus510a, the object to be processed530is provided over the rollers542.

The frame541is provided with the rotation mechanisms544. One of end portions of the rotation axis543is connected to the rotation mechanism544, and the other of the end portions of the rotation axis543is connected to the frame541. Alternatively, the both end portions of the rotation axis543are connected to the frame541. Note that a bearing546is provided between the frame541and the rotation axis543.

The cylindrical rollers542are fixed to the rotation axis543. The center axis of the roller542preferably has a region overlapping with the center axis of the rotation axis543.

When the rotation mechanism544and the rotation axis543are connected to each other, the rollers542can be rotated, so that the object to be processed530over the rollers542can be moved in the first horizontal direction (X-direction).

Note that although not limited thereto, a mode where three rollers542are fixed to one rotation axis543is illustrated inFIGS. 16(A) and 16(B), there is no such limitation. For example, as illustrated inFIG. 17(A), one long roller542may be fixed to the rotation axis543. Alternatively, as illustrated inFIG. 17(B), more rollers than those inFIGS. 16(A) and 16(B)may be fixed to the rotation axis543.

These may be used as appropriate depending on the weight of the object to be processed530in order to suppress idling of the rollers542. In the case where the weight of the object to be processed530is large, it is preferable that the number of the rollers542be small so that the contact area with the object to be processed530becomes large and the load applied to the rollers542per unit area becomes small. Furthermore, in the case where the weight of the object to be processed530is small, it is preferable that the number of the rollers542be large so that the contact area with the object to be processed530becomes small and the load applied to the rollers542per unit area becomes large.

Alternatively, as illustrated inFIG. 17(C), a roller542bwhose diameter is smaller than that of the roller542and a rotation axis543bwhose diameter is smaller than that of the rotation axis543may be included. These are not connected to the rotation mechanism544and are connected to the frame541. When the roller and the rotation axis are small as described above, the weight can be reduced, leading to a reduction in the resistance of rotation. Thus, a load on the rotation mechanism544can be made small.

AlthoughFIGS. 16(A) and 16(B)illustrate an example including a set of the rotation axis543and the rollers542which is not connected to the rotation mechanism544, the rotation mechanism544may be connected to all sets of the rotation axes543and the rollers542as illustrated inFIG. 17(D).

Moreover,FIG. 17(E)is part of a top view of the first roller unit540and a cross-sectional view (Y3-Y4position) of a set of the roller542and the rotation axis543which is not connected to the rotation mechanism544. As illustrated above, in the set of the rollers542and the rotation axis543which is not connected to the rotation mechanism544, a bearing546may be provided between the rollers542and the rotation axis543in order to reduce the resistance of rotation.

The laser processing must be controlled so that the position of the object to be processed in the height direction is not changed in order to prevent a variation in the energy density of laser light on the irradiation surface.

In the structure using the X-Y stage, the position of the stage and the position of laser irradiation are always changed; therefore, the levelness of the stage and the planarity of the stage surface are important. In the case of using a large substrate, in particular, a large stage having high planarity is necessary, and thus the manufacturing cost becomes high. In addition, a sensor for keeping the levelness of the large stage including a movement mechanism and frequent maintenance are necessary.

On the other hand, the structure of one embodiment of the present invention in which the object to be processed is mounted over the rollers is a structure in which the position of the rollers and the position of laser irradiation are not changed. A mechanism for moving a large stage is not necessary, and thus there is less vibration, and tilt of the rollers due to a change over time is unlikely to be generated. Accordingly, it can be said that it is an apparatus that excels in maintainability. Furthermore, a small number of large components are used, an small motor or the like can be used as power, so that the manufacturing cost can be suppressed low.

FIG. 18(A)is a perspective view illustrating the second roller unit550. Furthermore,FIG. 18(B)is a top view of the second roller unit550, a cross-sectional view taken along X1-X2in the top view, and a cross-sectional view taken along Y1-Y2in the top view. The second roller unit550includes a plurality of frames551, a plurality of rollers552, a plurality of rotation axes553, a plurality of rotation mechanisms554, a plurality of bearings555, and a plurality of raising and lowering mechanisms556.

The frame551is provided with the rotation mechanisms554. One of end portions of the rotation axis553is connected to the rotation mechanism554, and the other of the end portions of the rotation axis553is connected to the frame551. Note that a bearing559is provided between the frame551and the rotation axis553. Moreover, the frame551is provided with a plurality of bearings555that support the rotation axes553.

The cylindrical rollers552are fixed to the rotation axis553. The center axis of the roller552preferably has a region overlapping with the center axis of the rotation axis553.

When the rotation mechanism554and the rotation axis553are connected to each other, the rollers552can be rotated, so that the object to be processed530can be mounted over the rollers552and moved in the second horizontal direction (Y-direction).

The raising and lowering mechanisms556includes a cylinder portion557and a rod portion558and can raise and lower the rod portion558by controlling power.

The frame551is connected to the rod portions558. Accordingly, the frame551and the rollers552can be raised and lowered by operations of the raising and lowering mechanisms556. Note that althoughFIGS. 18(A) and 18(B)illustrate a mode in which the rod portion558and the bearing555are connected to each other, it is acceptable as long as the rod portion558is connected to any of parts of the frame551.

Note that in the central portion of the second roller unit550, which is an optical path of laser light, the roller552and the rotation axis553are not provided. Therefore, in the central row inFIG. 18(B), one set of the roller552, the rotation axis553, and the rotation mechanism554is provided on each of right and left.

AlthoughFIGS. 18(A) and 18(B)illustrate an example in which sets of the rollers552, the rotation axes553, and the rotation mechanisms554are provided in three rows, it is acceptable as long as the sets are provided in at least two rows in order to move the object to be processed530.

Furthermore, when the first roller unit540and the second roller unit550are provided to overlap with each other, the roller552is raised and lowered in a region of the first roller unit540where the roller542is not provided. Accordingly, a width W552of the roller552(which corresponds to the height of the cylinder) is made smaller than a distance W542(seeFIG. 16(B)) between the adjacent rollers542, whereby raising and lowering becomes possible.

Moreover, in order to mount the object to be processed530on the rollers552and move it, the heads need to be raised to a positon higher than the heads of the rollers542. Accordingly, when the radius of the roller542is R42and the radius of the rotation axis553right under the roller542is R553, the radius R553of the roller552is made larger than 2R542+R553, whereby the roller552can be raised to a desired height. Note that in the case where the radius R553of the roller552is smaller than or equal to 2R542+R553, the rotation axis553may collide with the roller542when the roller552is raised.

For the roller542and the roller552, for example, a cylinder of a metal, a resin, or the like, a cylinder of an elastic body such as rubber, a member provided with an elastic body such as rubber on a surface of a cylinder of a metal or a resin, and the like can be used. Note that in order to prevent deterioration due to electrification of a device included in the object to be processed530, the above resin or elastic body preferably has conductivity.

As the rotation mechanism544and the rotation mechanism554, a motor can be used, for example. A motor with high positional accuracy, such as a stepping motor, is preferable in order that the object to be processed530is subjected to laser processing at a desired position thereof. Furthermore, a sensor that detects the position of the object to be processed530may be provided to prevent misalignment due to the influence of a backlash or the like.

As the raising and lowering mechanisms556, an electric cylinder, a hydraulic cylinder, an air cylinder, or the like, using a ball screw or the like can be used.

Note that there is no limitation on the number of components in the first roller unit540and the second roller unit550, and an appropriate number may be selected in accordance with the size or the weight of the object to be processed530.

Here, laser irradiation of the object to be processed530provided over the first roller unit540will be described.

FIGS. 19(A) and 19(B)andFIGS. 20(A) and 20(B)are top views, front views, and side views illustrating a method in which the object to be processed530is irradiated with the linear beam527to form a processed region531in the entire surface (effective region). Note that for simplification of the drawings, the frame541and the rotation mechanism544of the first roller unit540and the frame551and the rotation mechanism554of the second roller unit550are not illustrated. Furthermore, the linear beam527shows an irradiation position, and the linear beam527is fixed in the vicinity of the center of the chamber511.

The length of the linear beam527is ideally greater than or equal to the length of one side of the object to be processed530. In this case, only by moving the linear beam527or the object to be processed530in one horizontal direction, the entire object to be processed530can be subjected to laser processing. However, a large optical component, which is very expensive, is needed to form a linear beam corresponding to the length of one side of a large glass substrate having the size of G10 (2880×3130 mm) or the like used for manufacture of a display device.

Furthermore, as the linear beam becomes longer, it is more difficult to secure necessary energy density; therefore, a laser oscillator with higher output is also needed. Accordingly, it is practical to use a linear beam that is shorter than the length of the one side of the object to be processed530and perform laser irradiation on a desired region several times.

A method for irradiation of the surface of the object to be processed530with the linear beam527having a length of approximately ½ of the length of the one side of the object to be processed530a plurality of times will be described below. Only a desired region of the object to be processed530can be irradiated with the linear beam527in accordance with the purposes. Alternatively, the entire surface of the object to be processed530can be subjected to irradiation. That is, the processed regions531may be formed at intervals, and irradiation with the linear beam527may be performed to overlap with part of the processed region531.

First, the object to be processed530is placed at a predetermined position over the roller542. At this time, the raising and lowering mechanism556of the second roller unit550is in a state of being lowered, and at least the head of the roller552is at a position lower than that of the head of the roller542. Then, with the vicinity of the first vertex V1of the object to be processed530serving as a starting point of processing, the rollers542are rotated while irradiation with the linear beam527is performed, the object to be processed530is moved in the +X direction (seeFIG. 19(A)).

Next, the object to be processed530is moved by the distance A corresponding to the length of the first side, and then the irradiation with the linear beam527is terminated. Then, at least the heads of the rollers552are set at a position higher than that of the heads of the rollers542using the raising and lowering mechanism556to lift the object to be processed530. Then, the rollers552are rotated, and the object to be processed530is moved in the −Y direction (seeFIG. 19(B)).

The object to be processed530is moved by ½ of the distance B corresponding to the length of the second side of the object to be processed530, and then at least the heads of the rollers552is set at a position lower than that of the heads of the rollers542using the raising and lowering mechanism556, and thus the object to be processed530is mounted over the rollers542. Then, irradiation with the linear beam527is started, and the rollers542are rotated to move the object to be processed530in the −X direction (seeFIG. 20(A)).

Next, the object to be processed530is moved by the distance A, and then the irradiation with the linear beam527is terminated (seeFIG. 20(B)). Through the above operations, the entire surface of the object to be processed530can be irradiated with the linear beam527.

Note that although the case where the length of the linear beam527is approximately ½ of the one side of the object to be processed530is described in the above, the basic operation is the same even in the case where the length of the linear beam527is shorter. Note that in the case where the length of the linear beam527is approximately ⅓ of the length of the one side of the object to be processed530, the number of times of movement in the −Y direction is two, and the number of times of laser irradiation is three. Furthermore, in the case where the length of the linear beam527is approximately ¼ of the length of the one side of the object to be processed530, the number of times of movement in the −Y direction is three, and the number of times of laser irradiation is four. Moreover, as the length of the linear beam is shorter, the distance of movement in the Y-direction is larger; therefore, the size of the chamber511needs to be increased.

Next, the object to be processed530will be described. As illustrated inFIG. 21(A), the object to be processed530can be formed using a flat-plate-like substrate535and a layer538provided over the substrate535. The layer538can be irradiated with the linear beam527through the substrate535. The substrate535is a glass substrate having relatively high transmittance of laser light, or the like and is formed of a material through which the layer538can be irradiated with the linear beam527having a required energy density. The layer538includes a resin layer of polyimide or the like, for example, and is a layer in which the resin layer can be processed by being irradiated with the linear beam527having a given intensity or higher.

The resin layer is provided in contact with an entire surface of the substrate535. Alternatively, it may be provided partly in contact with the substrate535. By laser processing of the resin layer, the adhesion between the resin layer and the substrate535is decreased, so that the layer538and the substrate535can be separated from each other.

Furthermore, as illustrated inFIG. 21(B), the object to be processed530can have a structure including the substrate535, a substrate537, and the layer538sandwiched between the two substrates.

Furthermore, althoughFIGS. 15(A) and 15(B)illustrate an example in which the mirror523cis provided so that an incident angle of the laser light526is approximately 45° as illustrated inFIG. 22(A), the incident angle of the laser light526with respect to the mirror523cmay be an angle smaller than 45° as illustrated inFIG. 22(B). For example, the incident angle is larger than or equal to 20° and smaller than 45°, preferably larger than or equal to 25° and smaller than or equal to 40, further preferably larger than or equal to 30° and smaller than or equal to 40.

Alternatively, as illustrated inFIG. 22(C), the incident angle of the laser light526with respect to the mirror523cmay be an angle larger than 45°. For example, the incident angle is larger than 45° and smaller than or equal to 70°, preferably larger than or equal to 50° and smaller than or equal to 65°, further preferably larger than or equal to 50° and smaller than or equal to 60°.

The incident angle of the laser light526with respect to the mirror523cis changed as illustrated inFIGS. 22(A) to 22(C), whereby the object to be processed530can be obliquely irradiated with the linear beam527. Therefore, when the object to be processed530has a structure illustrated inFIGS. 20(A) and 20(B), and the layer538is irradiated with the linear beam through the substrate535, for example, processing defect caused by the shadow due to a foreign substance attached to the substrate535can be suppressed. Furthermore, it is more effective to perform processing at the above angle.

As a laser irradiation method in this case, the object to be processed530is irradiated with the linear beam in any two of the modes illustrated inFIGS. 22(A) to 22(C). For example, any one of the modes illustrated inFIGS. 22(A) to 22(C)is selected to perform first laser irradiation on the object to be processed530, and the mode other than the mode selected for the first laser irradiation is selected to perform second laser irradiation on the region that has been irradiated.

Note that the incident angle of the laser light526with respect to the mirror523ccan be easily changed by change of the angle of the mirror523c. For example, as illustrated inFIGS. 22(A) to 22(C), a jig528provided for the mirror523cis rotated with a motor529. At this time, a mechanism for vertical moving of the mirror523cto the lens522may be used so that a focal point of the linear beam527is formed in a desired region.

FIG. 23illustrates an example of a structure of the above laser processing apparatus to which an apparatus for carrying out/in the object to be processed530is added.

A processing apparatus510billustrated inFIG. 23includes a laser processing apparatus, a transfer chamber561, load chambers562and563, and unload chambers564and565. Note that inFIG. 23, gate valves and the like are omitted and each chamber is simply illustrated. Note that althoughFIG. 23illustrates a structure including two load chambers and two unload chambers, a structure including one load chamber and one unload chamber may be employed. Alternatively, a structure may be employed in which one chamber serves as a load chamber and an unload chamber.

The transfer chamber561includes a transfer mechanism560and a member can be carried out of/in each chamber before and after processing.

The transfer mechanism560is an arm-type robot and includes a raising and lowering mechanism, a joint mechanism, an arm, a fork, and the like. The object to be processed530and the like can be transferred by a telescopic operation of the arm using the joint mechanism or the like as an axis, an upward/downward operation of the raising and lowering mechanism, and the like.

Furthermore, the object to be processed530is supported by the fork with an adsorption mechanism. As the adsorption mechanism, a vacuum suction mechanism can be used, for example. Furthermore, the adsorption mechanism may have a sucker.

The load chambers562and563include cassettes566aand566band can store the object to be processed530which has not been processed.

The unload chambers564and565include cassettes566cand566dand can store a member530athat has been processed and has been carried out of the chamber511of the laser processing apparatus.

Next, an example of a process using the processing apparatus510bis briefly described. Note that the object to be processed530has the mode illustrated inFIG. 21(A), and the purpose is laser processing of the resin provided over the substrate535.

First, the cassette566awhere the object to be processed530is stored is set in the load chamber562, and the object to be processed530is transferred to the chamber511of the laser processing apparatus by the transfer mechanism560.

Here, a method for transfer to the chamber511will be described with reference toFIGS. 24(A) to 24(D). First, the fork of the transfer mechanism560is inserted into the load chamber562, and the object to be processed530is taken out from the cassette566a. At this time, the rollers552of the second roller unit550are in a state of being lowered (seeFIG. 24(A)).

Next, the object to be processed530over the fork of the transfer mechanism560is transferred to predetermined X and Y positions over the first roller unit540and the second roller unit550in the chamber511. Then, the rollers552are raised by the raising and lowering mechanisms556to lift the object to be processed530from the fork of the transfer mechanism560(seeFIG. 24(B)).

Next, the fork of the transfer mechanism560is moved to the outside of the chamber511(seeFIG. 24(C)).

Then, the rollers552are lowered by the raising and lowering mechanisms556to set the object to be processed530onto the rollers542. Alternatively, the rollers552may be rotated to move the object to be processed530to a desired Y position and then may be lowered. Through the above, the object to be processed530can be transferred to the chamber511(seeFIG. 24(D)).

Next, the object to be processed530set onto the rollers552is moved to desired X and Y positions where laser processing is started, using the rollers542or the rollers552.

Next, by the method described inFIG. 19andFIG. 20, the object to be processed530is subjected to laser processing to form the member530athat has been processed. Then, the member530ais moved to predetermined X and Y positions using the rollers542or the rollers552.

Next, the rollers552are raised to lift the member530afrom the rollers542, and the fork of the transfer mechanism560is inserted between the rollers542and the member530a. Then, the rollers552are lowered to place the member530aover the fork.

Next, the member530aplaced over the fork of the transfer mechanism560is transferred to the outside of the chamber511, and the member530ais stored in the cassette566cset in the unload chamber564.

In this manner, in the laser processing apparatus of one embodiment of the present invention, the object to be processed530can be carried in and the member530acan be carried out using the rollers for moving the object to be processed530and the like. In the carried-in/out method, a lift pin or the like is not used, so that the apparatus can be manufactured at low cost.

Note that the first roller unit540and the second roller unit550can also be applied to a structure in which irradiation with laser light is performed from the upper side of the object to be processed530as illustrated inFIG. 25.

A laser processing apparatus510cillustrated inFIG. 25has a structure similar to that of the laser processing apparatus510aillustrated inFIGS. 15(A) and 15(B)excluding a structure of part of the laser irradiation mechanism and a structure of part of the second roller unit550.

In the laser processing apparatus510c, the optical system unit521to the lens522can be provided above the first roller unit540and the second roller unit550, and thus the mirror523aand the mirror523billustrated inFIG. 15(B)can be omitted.

Moreover, an optical path of laser light does not need to be provided in the second roller unit550as illustrated inFIG. 26; therefore, the roller552in the central portion of the second roller unit550can be provided. Accordingly, all the rollers552in the center row can be fixed to one rotation axis553, and thus in the center row inFIG. 26(B), the rollers552, the rotation axis553, and the rotation mechanism554form one set.

In this embodiment, a structure of the laser processing apparatus has been described as one embodiment of the present invention. Note that the structure in which the first roller unit540and the second roller unit550included in the laser processing apparatus are combined can be used not only for laser processing but also for other applications.

In this embodiment, a method for manufacturing a display device that can be manufactured using the laser processing apparatus or the stack processing apparatus of one embodiment of the present invention will be described.

One embodiment of the present invention is a separation method in which a resin layer is formed over a substrate, a transistor including an oxide semiconductor in a channel formation region is formed over the resin layer, the resin layer is irradiated with laser light that is shaped into a linear beam, and the transistor and the substrate are separated.

A metal oxide is used for the channel formation region of the transistor. With the use of a metal oxide, the maximum process temperature can be lower than that in the case of using low-temperature polysilicon (LTPS).

When LTPS is used for the channel formation region of the transistor, the maximum process temperature reaches approximately 500° C. to 550° C. Thus, the resin layer needs to have heat resistance. Furthermore, the resin layer is required to have a larger thickness to relieve the damage to an insulating layer or the like at the periphery of the resin layer in a laser crystallization step. In addition, when the resin layer is irradiated with laser light, a large thickness of the resin layer is required to suppress the degradation of characteristics caused by irradiation of the channel formation region of the completed transistor with laser light.

In contrast, the transistor using a metal oxide does not need heat treatment at high temperatures, and can be formed at a temperature lower than or equal to 350° C., or even lower than or equal to 300° C. Therefore, the resin layer is not required to have high heat resistance. Accordingly, a relatively inexpensive resin whose heat-resistance temperature is low can be used for the resin layer. Furthermore, the transistor using a metal oxide does not need a laser crystallization step. Moreover, the metal oxide has a wide band gap greater than or equal to 2.5 eV and lower than or equal to 3.5 eV, and absorbs a smaller amount of laser light with a specific wavelength than silicon. Thus, there is no problem when the resin layer has a small thickness. Since the resin layer is not required to have high heat resistance and can be thinned, the manufacturing costs of a device can be significantly reduced. Furthermore, a metal oxide is preferably used, in which case the process can be simplified as compared with the case where LTPS is used.

In one embodiment of the present invention, a transistor or the like is formed at a temperature lower than or equal to the allowable temperature limit of the resin layer. Here, the heat resistance of the resin layer can be measured by, for example, a weight loss percentage due to heat, specifically, the 5% weight loss temperature, or the like. The 5% weight loss temperature of the resin layer is preferably lower than or equal to 450° C., further preferably lower than or equal to 400° C., still further preferably lower than 350° C. For example, a transistor is formed at a temperature lower than or equal to 350° C., or even lower than or equal to 300° C.

In one embodiment of the present invention, a resin layer may be formed using a photosensitive material. With the photosensitive material, a resin layer with a desired shape can be easily formed. For example, a resin layer having an opening or a resin layer having two or more regions with different thicknesses can be easily formed. Accordingly, the resin layer can be prevented from hindering formation of a back gate, an external connection terminal, a through electrode, or the like.

A flexible display device can be manufactured using the separation method of a structure body of one embodiment of the present invention. An example of a manufacturing method of a flexible display device will be described with reference toFIG. 27andFIG. 28.

First, as illustrated inFIG. 27(A), a stack in which a stack110and a stack120are attached to each other with an adhesive layer132is referred to as a stack130.

The stack110includes, for example, a substrate111, a separation layer171, a resin layer112, an insulating layer113, a first element layer114, and a second element layer131.

The stack120includes, for example, a substrate121, a separation layer172, a resin layer122, an insulating layer123, and a functional layer124. Here, the stack130corresponds to the object to be processed30described in Embodiment 1 with reference toFIG. 10(B). Furthermore, the substrate111corresponds to the substrate35, and the substrate121corresponds to the substrate37. Moreover, the separation layer171, the resin layer112, the insulating layer113, the first element layer114, the second element layer131, the functional layer124, the insulating layer123, the resin layer122, and the separation layer172correspond to the layer38.

For the substrates111and121, a rigid substrate can be used, and for example, a glass substrate can be used. Since the resin layers112and122are irradiated with laser light through the substrates111and121in a later step, the substrates111and121preferably have high transmittance of the laser light.

For the separation layers171and172, a metal or a metal oxide can be used. As the metal, for example, various metals such as titanium, molybdenum, aluminum, tungsten, and tantalum or an alloy thereof can be used.

Moreover, as the metal oxide, an oxide of any of a variety of metals can be used. For example, titanium oxide, molybdenum oxide, aluminum oxide, tungsten oxide, indium tin oxide, indium zinc oxide, or an In—Ga—Zn oxide, and the like can be given.

For the resin layers112and122, a photosensitive and thermosetting material can be used, for example. Specifically, a resin such as polyimide is preferably used. A structure capable of separation by changing the adhesion between the separation layers171and172and the resin layers112and122can be obtained.

For the insulating layers113and123, an inorganic insulating layer can be used, for example.

The first element layer114can include, for example, a transistor using an oxide semiconductor in a channel formation region.

The second element layer131can include an EL element, for example.

The functional layer124can include at least one of a coloring layer such as a color filter, a light-blocking layer such as a black matrix, and a sensor element such as a touch sensor.

Next, a region to be processed (a region including the separation layer172and the resin layer122) is irradiated with laser light160from the substrate121side as illustrated inFIG. 27(B). A structure change due to heating of the separation layer172, the resin layer122, and the interface by the irradiation with the laser light160can reduce the adhesion between the both. The irradiation with the laser light160is preferably performed with a linear beam, and the laser processing apparatus of one embodiment of the present invention can be used.

Note that since the region to be processed is irradiated with the laser light through the substrate121, when a foreign substance or the like exists on a surface of the substrate121, the laser light with which the region to be processed is irradiated is blocked, which may result in local generation of defective separation in a later step. However, by an absorption of laser light by a metal or a metal oxide which is used as the separation layer172, the adhesion between the separation layer172and the resin layer122can be reduced in a range wider than the region that is irradiated with the laser light. Accordingly, even in the case where the laser light is blocked by a foreign substance or the like on the surface of the substrate121, defective separation in a later step can be suppressed.

Next, as illustrated inFIG. 27(C), a stack of the substrate121and the separation layer172is separated from the stack130by a physical means. For example, the separation can be performed by fixing the substrate111with a suction stage or the like, and applying physical force such that the substrate121side is moved in the upward direction.

Next, as illustrated inFIG. 27(D), the exposed resin layer122and a substrate151are attached to each other. The substrate151preferably has flexibility. For example, the resin layer122and the substrate151can be attached to each other with an adhesive.

Next, as illustrated inFIG. 28(A), the region to be processed (a region including the separation layer171and the resin layer112) is irradiated with the laser light160from the substrate111side.

Next, as illustrated inFIG. 28(B), a stack of the substrate111and the separation layer171is separated from a stack illustrated inFIG. 28(A)by a physical means.

Next, as illustrated inFIG. 28(C), the exposed resin layer112and a substrate141are attached to each other. The substrate141preferably has flexibility.

Note that although a structure in which the resin layers112and122are left is described in the above step, the resin layers112and122are preferably removed by ashing treatment in the case where they are not transparent but colored.

Through the above process, a flexible display device100illustrated inFIG. 28(D)can be fabricated.

By using the separation process described in Embodiment 2, a hybrid display that can perform hybrid display can be manufactured relatively easily. In this embodiment, a hybrid display will be described.

Hybrid display is a method for displaying a letter or an image using reflected light and self-emitted light together in one panel that complement the color tone or light intensity of each other. Alternatively, hybrid display is a method for displaying a letter and/or an image using light from a plurality of display elements in one pixel or one subpixel. Note that when a hybrid display that performs hybrid display is locally observed, a pixel or a subpixel performing display using any one of the plurality of display elements and a pixel or a subpixel performing display using two or more of the plurality of display elements are included in some cases.

Note that in this specification and the like, one satisfying any one or a plurality of expressions of the above-described structures is referred to as hybrid display.

Furthermore, a hybrid display includes a plurality of display elements in one pixel or one subpixel. Note that as the plurality of display elements, for example, reflective elements that reflect light and self-luminous elements that emit light can be given. Note that the reflective element and the self-luminous element can be controlled independently. A hybrid display has a function of displaying a letter and/or an image using one or both of reflected light and self-emitted light in a display portion.

The display device of one embodiment of the present invention can include a pixel provided with a first display element that reflects visible light. Alternatively, the display device can include a pixel provided with a second display element that emits visible light. Alternatively, the display device can include a pixel provided with the first display element and the second display element.

In this embodiment, a display device including the first display element that reflects visible light and the second display element that emits visible light will be described.

The display device has a function of displaying an image by one or both of first light reflected by the first display element and second light emitted from the second display element. Alternatively, the display device has a function of expressing grayscales by individually controlling the amount of the first light reflected by the first display element and the amount of the second light emitted from the second display element.

Furthermore, the display device preferably has a structure including a first pixel that expresses grayscales by controlling the amount of reflected light of the first display element and a second pixel that expresses grayscales by controlling the amount of light emitted from the second display element. For example, a plurality of each of the first pixels and the second pixels are arranged in a matrix to form a display portion.

In addition, it is preferable that the first pixels and the second pixels be arranged in a display region with the same number and the same pitch. At this time, the adjacent first and second pixels can be collectively referred to as a pixel unit. Accordingly, as described later, an image displayed only by a plurality of first pixels, an image displayed only by a plurality of second pixels, and an image displayed by both the plurality of first pixels and the plurality of second pixels can be displayed in the same display region.

As the first display element included in the first pixel, an element that performs display by reflecting external light can be used. Such an element does not include a light source, and thus, the power consumption at the time of display can be significantly reduced.

As the first display element, typically, a reflective liquid crystal element can be used. Alternatively, as the first display element, an element or the like using a microcapsule method, an electrophoretic method, an electrowetting method, an Electronic Liquid Powder (registered trademark) method, or the like can be used, other than a shutter type MEMS (Micro Electro Mechanical System) element or an optical interference type MEMS element.

As the second display element included in the second pixel, an element that includes a light source and performs display utilizing light from the light source can be used. It is particularly preferable to use an electroluminescent element in which light emission can be extracted from a light-emitting substance by application of an electric field. Since the luminance and the chromaticity of light emitted from such a pixel are not affected by external light, display with high color reproducibility (a wide color gamut) and high contrast can be performed; that is, vivid display can be performed.

As the second display element, for example, a self-luminous light-emitting element such as an OLED (Organic Light Emitting Diode), an LED (Light Emitting Diode), a QLED (Quantum-dot Light Emitting Diode), or a semiconductor laser can be used. Alternatively, a combination of a backlight that is a light source and a transmissive liquid crystal element that controls the amount of transmitted light from a backlight may be used as the display element included in the second pixel.

The first pixel can have, for example, a structure including a subpixel exhibiting white (W) or subpixels exhibiting light of three colors of red (R), green (G), and blue (B). Moreover, the second pixel can also have, for example, a structure including a subpixel exhibiting white (W) or subpixels exhibiting light of three colors of red (R), green (G), and blue (B). Note that the first pixel and the second pixel may each include subpixels of four colors or more. As the number of kinds of subpixels is increased, the power consumption can be reduced and the color reproducibility can be improved.

In one embodiment of the present invention, a first mode in which an image is displayed by the first pixels, a second mode in which an image is displayed by the second pixels, and a third mode in which an image is displayed by the first pixels and the second pixels can be switched. In addition, as described in Embodiment 1, a different image signal is input to each of the first pixel and the second pixel, so that a composite image can be displayed.

The first mode is a mode in which an image is displayed using light reflected from the first display element. The first mode, which requires no light source, is a driving mode with extremely low power consumption. For example, the first mode is effective in the case where external light has a sufficiently high illuminance and is white light or light near white light.

The first mode is a display mode suitable for displaying, for example, text data of a book, a document or the like. Furthermore, since reflected light is used, eye-friendly display can be performed, so that an effect of less eyestrain can be obtained.

The second mode is a mode in which an image is displayed utilizing light emitted from the second display element. Thus, an extremely clear display (with high contrast and high color reproducibility) can be performed regardless of the illuminance and the chromaticity of external light. For example, the second mode is effective when the illuminance of external light is extremely low, e.g., during the night or in a dark room. When display of a bright image is performed under weak external light, a user may feel that the image is too bright. To prevent this, display with reduced luminance is preferably performed in the second mode. Thus, not only a reduction in glare but also low power consumption can be achieved. The second mode is a mode suitable for displaying a clear image, a smooth moving image, and the like.

The third mode is a mode in which display is performed utilizing both reflected light from the first display element and light emitted from the second display element. Specifically, the driving is performed such that light from the first pixel and light from the second pixel adjacent to the first pixel are mixed to express one color. The third mode can perform more vivid display than the first mode, and the power consumption can be lower than that in the second mode. For example, the third mode is effective when the illuminance of external light is relatively low, e.g., under indoor illumination or in the morning or evening, or when the chromaticity of the external light is not white.

A more specific example of one embodiment of the present invention will be described below with reference to drawings.

[Structure Example of Display Device]

FIG. 29is a diagram illustrating a pixel array70included in the display device of one embodiment of the present invention. The pixel array70includes a plurality of pixel units75arranged in a matrix. The pixel units75each include a pixel76and a pixel77.

FIG. 29illustrates an example of the case where the pixel76and the pixel77each include display elements corresponding to three colors of red (R), green (G), and blue (B).

The pixel76includes a display element76R corresponding to red (R), a display element76G corresponding to green (G), and a display element76B corresponding to blue (B). The display elements76R,76G, and76B are each a second display element utilizing light from a light source.

The pixel77includes a display element77R corresponding to red (R), a display element77G corresponding to green (G), and a display element77B corresponding to blue (B). The display elements77R,77G, and77B are each a first display element utilizing reflection of external light.

The above is the description of the structure example of the display device.

[Structure Example of Pixel Unit]

Next, the pixel unit75will be described with reference toFIGS. 30(A), 30(B), and30(C).FIGS. 30(A), 30(B), and30(C) are schematic views illustrating structure examples of the pixel unit75.

First Mode

FIG. 30(A)illustrates an example of an operation mode in which an image is displayed by driving the display element77R, the display element77G, and the display element77B, which reflect external light. As illustrated inFIG. 30(A), for example, in the case where the illuminance of external light is sufficiently high, the pixel76is not driven and only the colors of the light (the light R1, the light G1, and the light B1) from the pixel77are mixed, whereby the light79of a predetermined color can be emitted from the pixel unit75to the display surface side. Thus, driving with extremely low power consumption can be performed.

Second Mode

FIG. 30(B)illustrates an example of an operation mode in which an image is displayed by driving the display element76R, the display element76G, and the display element76B. As illustrated inFIG. 30(B), for example, in the case where the illuminance of external light is extremely low, the pixel77is not driven and only the colors of the light (the light R2, the light G2, and the light B2) from the pixel76are mixed, whereby the light79of a predetermined color can be emitted from the pixel unit75to the display surface side. Thus, vivid display can be performed. Furthermore, by lowering the luminance when the illuminance of external light is low, a user can be prevented from feeling glare and power consumption can be reduced.

Third Mode

FIG. 30(C)illustrates an example of an operation mode in which an image is displayed by driving both of the display element77R, the display element77G, and the display element77B, which reflect external light, and the display element76R, the display element76G, and the display element76B, which emit light. As illustrated inFIG. 30(C), the six colors of the light, i.e., the light R1, the light G1, the light B1, the light R2, the light G2, and the light B2are mixed, whereby light79of a predetermined color can be emitted from the pixel unit75to the display surface side.

The above is the description of the structure example of the pixel unit75.

A specific structure example of the hybrid display described in Embodiment 4 will be described below. A display panel described below as an example is a display panel which includes both a reflective liquid crystal element and a light-emitting element and can perform display both in a transmissive mode and in a reflective mode.

Structure Examples

FIG. 31(A)is a block diagram illustrating an example of a structure of a display device400. The display device400includes a plurality of pixels410arranged in a matrix in a display portion362. Furthermore, the display device400includes a circuit GD and a circuit SD. In addition, the plurality of pixels410arranged in a direction R, and a plurality of wirings G1, a plurality of wirings G2, a plurality of wirings ANO, and a plurality of wirings CSCOM, which are electrically connected to the circuit GD are included. Moreover, the plurality of pixels410arranged in a direction C, and a plurality of wirings S1and a plurality of wirings S2that are electrically connected to the circuit SD are included.

Note that although a structure including one circuit GD and one circuit SD is illustrated here for simplification, the circuit GD and the circuit SD for driving a liquid crystal element and the circuit GD and the circuit SD for driving a light-emitting element may be provided separately.

The pixels410includes a reflective liquid crystal element and a light-emitting element. In the pixel410, the liquid crystal element and the light-emitting element have a portion overlapping with each other.

FIG. 31(B1) illustrates a structure example of a conductive layer311bincluded in the pixel410. The conductive layer311bfunctions as a reflective electrode of the liquid crystal element in the pixel410. Furthermore, the conductive layer311bis provided with an opening451.

InFIG. 31(B1), a light-emitting element360positioned in a region overlapping with the conductive layer311bis shown by a dashed line. The light-emitting element360is provided to overlap with the opening451of the conductive layer311b. Thus, light emitted by the light-emitting element360is emitted to the display surface side through the opening451.

InFIG. 31(B1), the pixels410adjacent in the direction R are pixels corresponding to different colors. At this time, as illustrated inFIG. 31(B1), the openings451in two pixels adjacent in the direction R are preferably provided in different positions in the conductive layers311bso as not to be arranged in a line. This allows two light-emitting elements360to be apart from each other, thereby preventing a phenomenon in which light emitted by the light-emitting element360enters a coloring layer included in the adjacent pixel410(also referred to as crosstalk). Furthermore, since two adjacent light-emitting elements360can be arranged apart from each other, a high-resolution display device can be achieved even when EL layers of the light-emitting elements360are separately formed with a shadow mask or the like.

If the value of the ratio of the total area of the opening451to the total area of a non-opening portion is too large, display using the liquid crystal element gets dark. In addition, if the value of the ratio of the total area of the opening451to the total area of the non-opening portion is too small, display using the light-emitting element360gets dark.

Moreover, if the area of the opening451provided in the conductive layer311bfunctioning as a reflective electrode is too small, the efficiency of light which can be extracted from light emitted by the light-emitting element360is decreased.

The opening451can have, for example, a polygonal, quadrangular, elliptical, circular, or cross shape. Alternatively, the opening451may have a stripe shape, a slit shape, or a checkered pattern. Alternatively, the opening451may be close to the adjacent pixel. The opening451is preferably provided close to another pixel displaying the same color. Thus, crosstalk can be suppressed.

Circuit Configuration Example

FIG. 32is a circuit diagram illustrating a configuration example of the pixel410.FIG. 32illustrates two adjacent pixels410.

The pixel410includes a switch SW1, a capacitor C1, a liquid crystal element340, a switch SW2, a transistor M, a capacitor C2, the light-emitting element360, and the like. Furthermore, the wiring G1, the wiring G2, the wiring ANO, the wiring CSCOM, the wiring S1, and the wiring S2are electrically connected to the pixel410.FIG. 32also illustrates a wiring VCOM1electrically connected to the liquid crystal element340and a wiring VCOM2electrically connected to the light-emitting element360.

FIG. 32illustrates an example of the case where a transistor is used as each of the switch SW1and the switch SW2.

A gate of the switch SW1is connected to the wiring G1. One of a source and a drain of the switch SW1is connected to the wiring S1, and the other of the source and the drain is connected to one electrode of the capacitor C1and one electrode of the liquid crystal element340. The other electrode of the capacitor C1is connected to the wiring CSCOM. The other electrode of the liquid crystal element340is connected to the wiring VCOM1.

Moreover, a gate of the switch SW2is connected to the wiring G2. One of a source and a drain is connected to the wiring S2, and the other of the source and the drain is connected to one electrode of the capacitor C2and a gate of the transistor M. The other electrode of the capacitor C2is connected to one of a source and a drain of the transistor M and the wiring ANO. The other of the source and the drain of the transistor M is connected to one electrode of the light-emitting element360. The other electrode of the light-emitting element360is connected to the wiring VCOM2.

FIG. 32illustrates an example in which the transistor M includes two gates between which a semiconductor is provided and which are connected to each other. With this, current that can flow through the transistor M can be increased.

The wiring G1can be supplied with a signal for controlling the on/off state of the switch SW1. A predetermined potential can be supplied to the wiring VCOM1. The wiring S1can be supplied with a signal for controlling the orientation of liquid crystals of the liquid crystal element340. A predetermined potential can be supplied to the wiring CSCOM.

The wiring G2can be supplied with a signal for controlling the on/off state of the switch SW2. The wiring VCOM2and the wiring ANO can be supplied with potentials that cause a potential difference with which the light-emitting element360emits light. The wiring S2can be supplied with a signal for controlling the conduction state of the transistor M.

For example, in the case where display in the reflective mode is performed, the pixel410illustrated inFIG. 32can be driven with the signals supplied to the wiring G1and the wiring S1to perform display with the use of the optical modulation of the liquid crystal element340. Furthermore, in the case where display in the transmissive mode is performed, the pixel can be driven with the signals supplied to the wiring G2and the wiring S2, which makes the light-emitting element360emit light so as to perform display. In addition, in the case where the driving is performed in both modes, the pixel can be driven with the signals supplied to the wiring G1, the wiring G2, the wiring S1, and the wiring S2.

Note that althoughFIG. 32illustrates the example in which one pixel410includes one liquid crystal element340and one light-emitting element360, one embodiment of the present invention is not limited thereto.FIG. 33(A)illustrates an example in which one pixel410includes one liquid crystal element340and four light-emitting elements360(light-emitting elements360r,360g,360b, and360w).

In addition to the example inFIG. 32, the pixel410inFIG. 33(A)is connected to a wiring G3and a wiring S3.

In the example illustrated inFIG. 33(A), respective light-emitting elements exhibiting red (R), green (G), blue (B), and white (W) can be used for the four light-emitting elements360, for example. A reflective liquid crystal element exhibiting white can be used as the liquid crystal element340. Thus, in the case of performing display in the reflective mode, white display with high reflectivity can be performed. Moreover, in the case of performing display in the transmissive mode, display with a higher color rendering property can be performed at low power.

In addition,FIG. 33(B)illustrates a configuration example of the pixel410. The pixel410includes the light-emitting element360woverlapping with the opening of an electrode311and the light-emitting element360r, the light-emitting element360g, and the light-emitting element360bwhich are arranged around the electrode311. It is preferable that the light-emitting element360r, the light-emitting element360g, and the light-emitting element360bhave almost the same light-emitting area.

Structure Example of Display Panel

FIG. 34is a schematic perspective view of a display panel300of one embodiment of the present invention. The display panel300has a structure in which a substrate351and a substrate361are attached to each other. InFIG. 34, the substrate361is shown by a dashed line.

The display panel300includes a display portion362, a circuit364, a wiring365, and the like. The substrate351is provided with the circuit364, the wiring365, the conductive layer311bthat serves as a pixel electrode, and the like. Furthermore,FIG. 34illustrates an example in which an IC373and an FPC372are mounted on the substrate351. Thus, the structure illustrated inFIG. 34can be referred to as a display module including the display panel300, the FPC372, and the IC373.

As the circuit364, for example, a circuit functioning as a scan line driver circuit can be used.

The wiring365has a function of supplying signals and power to the display portion and the circuit364. The signal and the power are input to the wiring365from the outside through the FPC372or from the IC373.

FIG. 34illustrates an example in which the IC373is provided on the substrate351by a COG (Chip On Glass) method or the like. As the IC373, an IC functioning as a scan line driver circuit, a signal line driver circuit, or the like can be used. Note that a structure in which the IC373is not provided may be employed, for example, in the case where the display panel300includes circuits functioning as a scan line driver circuit and a signal line driver circuit or in the case where circuits functioning as a scan line driver circuit and a signal line driver circuit are externally provided and signals for driving the display panel300are input through the FPC372. Alternatively, the IC373may be mounted on the FPC372by a COF (Chip On Film) method or the like.

FIG. 34illustrates an enlarged view of part of the display portion362. The conductive layers311bincluded in a plurality of display elements are arranged in a matrix in the display portion362. The conductive layer311bhas a function of reflecting visible light and serves as a reflective electrode of the liquid crystal element340described later.

Furthermore, as illustrated inFIG. 34, the conductive layer311bhas an opening. The light-emitting element360is positioned closer to the substrate351than the conductive layer311bis. Light is emitted from the light-emitting element360to the substrate361side through the opening of the conductive layer311b.

Furthermore, an input device366can be provided over the substrate361. For example, a structure in which a sheet-like capacitive touch sensor is provided so as to overlap with the display portion362is employed. Alternatively, a touch sensor may be provided between the substrate361and the substrate351. In the case where the touch sensor is provided between the substrate361and the substrate351, an optical touch sensor including a photoelectric conversion element as well as a capacitive touch sensor may be used.

FIG. 35shows an example of cross sections of a part of a region including the FPC372, a part of a region including the circuit364, and a part of a region including the display portion362of the display panel exemplified inFIG. 34.

The display panel includes an insulating layer220between the substrate351and the substrate361. Moreover, the light-emitting element360, a transistor201, a transistor205, a transistor206, a coloring layer134, and the like are included between the substrate351and the insulating layer220. In addition, the liquid crystal element340, a coloring layer135, and the like are included between the insulating layer220and the substrate361. The substrate361and the insulating layer220are bonded to each other with an adhesive layer143. The substrate351and the insulating layer220are attached to each other with an adhesive layer142.

The transistor206is electrically connected to the liquid crystal element340, and the transistor205is electrically connected to the light-emitting element360. Both of the transistor205and the transistor206are formed on a surface of the insulating layer220on the substrate351side, and thus they can be formed through the same process.

The substrate361is provided with the coloring layer135, a light-blocking layer136, an insulating layer125, a conductive layer313functioning as a common electrode of the liquid crystal element340, an alignment film133b, an insulating layer117, and the like. The insulating layer117functions as a spacer for holding a cell gap of the liquid crystal element340.

Insulating layers such as an insulating layer211, an insulating layer212, an insulating layer213, an insulating layer214, and an insulating layer215are provided on the substrate351side of the insulating layer220. Part of the insulating layer211functions as a gate insulating layer of each transistor. The insulating layer212, the insulating layer213, and the insulating layer214are provided to cover the transistors. Furthermore, the insulating layer215is provided to cover the insulating layer214. The insulating layer214and the insulating layer215each have a function as a planarization layer. Note that although the case where three layers of the insulating layer212, the insulating layer213, and the insulating layer214are included as insulating layers that cover the transistors and the like is described here, not being limited to this, four or more layers may be used, or a single layer or two layers may be used. The insulating layer214functioning as a planarization layer is not necessarily provided if not needed.

Moreover, the transistor201, the transistor205, and the transistor206each include a conductive layer221part of which functions as a gate, a conductive layer222part of which functions as a source and a drain, and a semiconductor layer231. Here, a plurality of layers obtained by processing the same conductive film is shown with the same hatching pattern.

The liquid crystal element340is a reflective liquid crystal element. The liquid crystal element340has a stacked-layer structure in which a conductive layer311a, a liquid crystal312, and the conductive layer313are stacked. Moreover, the conductive layer311bthat reflects visible light is provided in contact with the substrate351side of the conductive layer311a. The conductive layer311bhas an opening251. Furthermore, the conductive layer311aand the conductive layer313contain a material transmitting visible light. In addition, an alignment film133ais provided between the liquid crystal312and the conductive layer311aand the alignment film133bis provided between the liquid crystal312and the conductive layer313.

A light diffusion plate129and a polarizing plate140are provided for an outer surface of the substrate361. As the polarizing plate140, a linear polarizing plate may be used or a circularly polarizing plate can also be used. As a circularly polarizing plate, for example, a stack of a linear polarizing plate and a quarter-wave retardation plate can be used. With this, reflection of external light can be suppressed. In addition, the light diffusion plate129is provided to suppress reflection of external light. The cell gap, alignment, drive voltage, and the like of the liquid crystal element used as the liquid crystal element340are adjusted depending on the kind of the polarizing plate so that desirable contrast is obtained.

In the liquid crystal element340, the conductive layer311bhas a function of reflecting visible light, and the conductive layer313has a function of transmitting visible light. Light entering from the substrate361side is polarized by the polarizing plate140, passes through the conductive layer313and the liquid crystal312, and is reflected by the conductive layer311b. Then, the light passes through the liquid crystal312and the conductive layer313again and reaches the polarizing plate140. In this case, optical modulation of the light can be controlled by controlling the alignment of the liquid crystal with a voltage applied between the conductive layer311band the conductive layer313. That is, the intensity of light emitted through the polarizing plate140can be controlled. Light other than that in a particular wavelength region is absorbed by the coloring layer135, so that extracted light is light exhibiting red, for example.

The light-emitting element360is a bottom-emission light-emitting element. The light-emitting element360has a stacked-layer structure in which a conductive layer191, an EL layer192, and a conductive layer193bare stacked in this order from the insulating layer220side. In addition, a conductive layer193ais provided to cover the conductive layer193b. The conductive layer193bcontains a material reflecting visible light, and the conductive layer191and the conductive layer193acontain a material transmitting visible light. Light emitted from the light-emitting element360is emitted to the substrate361side through the coloring layer134, the insulating layer220, the opening251, the conductive layer313, and the like.

Here, as illustrated inFIG. 35, the conductive layer311atransmitting visible light is preferably provided for the opening251. Accordingly, the liquid crystal312is aligned in a region overlapping with the opening251as well as in the other regions, whereby undesired light leakage caused by an alignment defect of the liquid crystal in the boundary portion of these regions can be suppressed.

An insulating layer217is provided over the insulating layer216which covers an end portion of the conductive layer191. The insulating layer217has a function as a spacer for preventing the insulating layer220and the substrate351from getting closer than necessary. In addition, in the case where the EL layer192or the conductive layer193ais formed using a shielding mask (metal mask), the insulating layer217may have a function of preventing the shielding mask from being in contact with the formation surface. Note that the insulating layer217is not necessarily provided if not needed.

One of a source and a drain of the transistor205is electrically connected to the conductive layer191of the light-emitting element360through a conductive layer224.

One of a source and a drain of the transistor206is electrically connected to the conductive layer311bthrough a connection portion207. The conductive layer311band the conductive layer311aare provided in contact with each other, and they are electrically connected to each other. Here, the connection portion207is a portion in which the conductive layers provided on both surfaces of the insulating layer220are connected through an opening provided in the insulating layer220.

A connection portion204is provided in a region in which the substrate351and the substrate361do not overlap with each other. The connection portion204is electrically connected to the FPC372through a connection layer242. The connection portion204has a structure similar to that of the connection portion207. On the top surface of the connection portion204, a conductive layer obtained by processing the same conductive film as the conductive layer311ais exposed. Thus, the connection portion204and the FPC372can be electrically connected to each other through the connection layer242.

A connection portion252is provided in part of a region in which the adhesive layer143is provided. In the connection portion252, the conductive layer obtained by processing the same conductive film as the conductive layer311ais electrically connected to part of the conductive layer313with a connector243. Accordingly, a signal or a potential input from the FPC372connected to the substrate351side can be supplied to the conductive layer313formed on the substrate361side through the connection portion252.

As the connector243, for example, a conductive particle can be used. As the conductive particle, a particle of an organic resin, silica, or the like whose surface is coated with a metal material can be used. It is preferable to use nickel or gold as the metal material because contact resistance can be reduced. It is also preferable to use a particle coated with layers of two or more kinds of metal materials, such as a particle coated with nickel and further with gold. Moreover, as the connector243, a material capable of elastic deformation or plastic deformation is preferably used. At this time, as illustrated inFIG. 35, the connector243which is the conductive particle has a shape that is vertically crushed in some cases. This increases the contact area between the connector243and a conductive layer electrically connected thereto, thereby reducing contact resistance and suppressing occurrence of defects such as disconnection.

The connector243is preferably provided so as to be covered with the adhesive layer143. For example, the connectors243are dispersed in the adhesive layer143which is not cured yet.

FIG. 35illustrates an example in which the transistor201is provided as an example of the circuit364.

The structure in which the semiconductor layer231where a channel is formed is provided between two gates is used as an example of the transistor201and the transistor205inFIG. 35. One of the gates is formed using the conductive layer221, and the other gate is formed using a conductive layer223which overlaps with the semiconductor layer231with the insulating layer212positioned therebetween. Such a structure enables the control of the threshold voltage of the transistor. In this time, the two gates may be connected to each other and supplied with the same signal to operate the transistor. Such a transistor can have higher field-effect mobility and thus have higher on-state current than other transistors. Consequently, a circuit capable of high-speed operation can be manufactured. Furthermore, the area occupied by a circuit portion can be reduced. The use of the transistor having a high on-state current can reduce signal delay in each wiring and can suppress display unevenness even if the number of wirings is increased when the size or resolution of a display panel is increased.

Note that the transistor included in the circuit364and the transistor included in the display portion362may have the same structure. Furthermore, a plurality of transistors included in the circuit364may all have the same structure, or transistors having different structures may be used in combination. Moreover, a plurality of transistors included in the display portion362may all have the same structure, or transistors having different structures may be used in combination.

A material through which impurities such as water and hydrogen do not easily diffuse is preferably used for at least one of the insulating layer212and the insulating layer213which cover each transistor. That is, the insulating layer212or the insulating layer213can function as a barrier film. Such a structure can effectively suppress diffusion of the impurities into the transistors from the outside, and a highly reliable display panel can be achieved.

The insulating layer125is provided on the substrate361side to cover the coloring layer135and the light-blocking layer136. The insulating layer125may have a function as a planarization layer. The conductive layer313can have a substantially flat surface owing to the insulating layer125, resulting in a uniform alignment state of the liquid crystal312.

A display panel illustrated inFIG. 36is an example of the case where a top-gate transistor is used as each transistor in the structure illustrated inFIG. 35. As described above, the use of a top-gate transistor can reduce parasitic capacitance, so that the frame frequency of display can be increased.

A transistor included in the display device of one embodiment of the present invention includes a conductive layer functioning as a gate electrode, a semiconductor layer, a conductive layer functioning as a source electrode, a conductive layer functioning as a drain electrode, and an insulating layer functioning as a gate insulating layer.

Note that there is no particular limitation on the structure of the transistor. For example, a planar transistor may be used, a staggered transistor may be used, or an inverted staggered transistor may be used. In addition, a top-gate transistor or a bottom-gate transistor may be used. Alternatively, gate electrodes may be provided above and below a channel.

There is no particular limitation also on the crystallinity of a semiconductor material used for the transistor, and an amorphous semiconductor or a semiconductor having crystallinity (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor partly including crystal regions) may be used. A semiconductor having crystallinity is preferably used because deterioration of the transistor characteristics can be suppressed.

Furthermore, as a semiconductor material used for the transistor, a metal oxide whose energy gap is greater than or equal to 2 eV, preferably greater than or equal to 2.5 eV, further preferably greater than or equal to 3 eV can be used. Typically, an oxide semiconductor containing indium, or the like can be used.

A transistor including an oxide semiconductor which has a wider bandgap and a lower carrier density than silicon has a low off-state current; therefore, charge accumulated in a capacitor that is series-connected to the transistor can be retained for a long time.

The semiconductor layer can be, for example, a film represented by an In-M-Zn-based oxide that contains indium, zinc, and M (a metal such as aluminum, titanium, gallium, germanium, yttrium, zirconium, lanthanum, cerium, tin, neodymium, or hafnium).

In the case where an oxide semiconductor that forms the semiconductor layer is an In-M-Zn-based oxide, it is preferable that the atomic ratio of the metal elements of a sputtering target used to deposit the In-M-Zn oxide satisfy In≥M and Zn≥M. As the atomic ratio of metal elements in such a sputtering targe, In:M:Zn=1:1:1, In:M:Zn=1:1:1.2, In:M:Zn=3:1:2, In:M:Zn=4:2:3, In:M:Zn=4:2:4.1, In:M:Zn=5:1:6, In:M:Zn=5:1:7, In:M:Zn=5:1:8, or the like is preferable. Note that the atomic ratio in the formed semiconductor layer varies from the above atomic ratio of metal elements of the sputtering target in a range of ±40%.

Moreover, a metal oxide formed of the above material or the like can function as a light-transmitting conductor by adjusting impurities, oxygen vacancies, and the like. Thus, when the components of the transistor such as the source electrode, the drain electrode, and the gate electrode, in addition to the semiconductor layer, are formed using a light-transmitting conductor, a light-transmitting transistor can be fabricated. The use of the light-transmitting transistor in a pixel of a display device allows light passing through a display element or light emitted from the display element to pass through the transistor; thus, the aperture ratio can be improved.

Alternatively, silicon may be used as a semiconductor in which a channel of a transistor is formed. Although amorphous silicon may be used as silicon, silicon having crystallinity is particularly preferably used. For example, microcrystalline silicon, polycrystalline silicon, single crystal silicon, or the like is preferably used. In particular, polycrystalline silicon can be formed at a lower temperature than single crystal silicon and has higher field-effect mobility and higher reliability than amorphous silicon.

The above-described display panel300is broadly divided into a region601including the light-emitting element, the transistors, and the like and a region602including the liquid crystal element and the like (seeFIG. 35andFIG. 36). A method for manufacturing the display panel300will be briefly described below with reference toFIGS. 37(A) to 37(C).

The display panel300can be manufactured relatively easily by the separation process described in Embodiment 2. First, a separation layer173and a resin layer175are provided over a substrate352, and the region601is completed over the resin layer175(seeFIG. 37(A)).

Next, a region to be processed (region including the separation layer173and the resin layer175) is irradiated with the laser light160(seeFIG. 37(B)), and the substrate352and the separation layer173are removed.

Next, the resin layer175is removed by ashing treatment, so that the conductive layer311aand the like are exposed. Then, the alignment film133ais formed in a region to be the display portion, and the other components of the region602that are separately formed are attached with the adhesive layer143so that the liquid crystal312is sandwiched therebetween (seeFIG. 37(C)). Through the above process, the display panel300illustrated inFIG. 35can be completed.

As electronic devices that can use the display device of one embodiment of the present invention, display devices, personal computers, image storage devices or image reproducing devices provided with storage media, cellular phones, game machines including portable game machines, portable data terminals, e-book readers, cameras such as video cameras and digital still cameras, goggle-type displays (head mounted displays), navigation systems, audio reproducing devices (e.g., car audio players and digital audio players), copiers, facsimiles, printers, multifunction printers, automated teller machines (ATM), vending machines, and the like can be given. Specific examples of these electronic devices are illustrated inFIG. 38.

FIG. 38(A)is a television, which includes a housing971, a display portion973, an operation key974, speakers975, a communication connection terminal976, an optical sensor977, and the like. The display portion973is provided with a touch sensor, and an input operation can also be performed. The display portion973can be formed using the laser processing apparatus or the stack processing apparatus of one embodiment of the present invention.

FIG. 38(B)is an information processing terminal, which includes a housing901, a display portion902, a display portion903, a sensor904, and the like. The display portion902and the display portion903are formed using one display panel and are flexible. Furthermore, the housing901is also flexible, can be used in a bent state as illustrated in the figure, and can also be used in a flat plate-like shape like a tablet terminal. The sensor904can sense the shape of the housing901, and for example, it is possible to switch display on the display portion902and the display portion903when the housing is bent. The display portion902and the display portion903can be formed using the laser processing apparatus or the stack processing apparatus of one embodiment of the present invention.

FIG. 38(C)is a digital camera, which includes a housing961, a shutter button962, a microphone963, a speaker967, a display portion965, operation keys966, a zoom lever968, a lens969, and the like. The display portion965can be formed using the laser processing apparatus or the stack processing apparatus of one embodiment of the present invention.

FIG. 38(D)is a wrist-watch-type information terminal, which includes a housing931, a display portion932, a wristband933, an operation button935, a crown936, a camera939, and the like. The display portion932may be a touch panel. The display portion932can be formed using the laser processing apparatus or the stack processing apparatus of one embodiment of the present invention.

FIG. 38(E)is an example of a cellular phone, which includes a housing951, a display portion952, an operation button953, an external connection port954, a speaker955, a microphone956, a camera957, and the like. The display portion952of the cellular phone includes a touch sensor. A variety of operations such as making a call and inputting text can be performed by touch on the display portion952with a finger, a stylus, or the like. The display portion952can be formed using the laser processing apparatus or the stack processing apparatus of one embodiment of the present invention.

FIG. 38(F)is a portable data terminal, which includes a housing911, a display portion912, a camera919, and the like. Input and output of information can be performed by a touch panel function of the display portion912. The display portion932can be formed using the laser processing apparatus or the stack processing apparatus of one embodiment of the present invention.

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