Patent Description:
Conventionally, there has been known a technology of peeling off a prescribed element from a substrate and transferring the element to a different substrate. This technology is described in <CIT>, <CIT>, <CIT>, and <CIT>.

However, in the conventional technology, there is a problem in that cracking or the like of the element is likely to occur when the element is transferred and it is difficult to increase the manufacturing yield.

The object of the present invention is to prevent the cracking or the like of a functional layer occurring when the functional layer is transferred and to increase the manufacturing yield.

A manufacturing method of an electronic device is defined in the independent method claim <NUM>.

According to the present invention, since the functional layer is separated from the first substrate and is transferred to the second substrate in a state in which the functional layer is held by the thin film holding layer, the cracking or the like of the functional layer can be prevented, by which the manufacturing yield can be increased.

A manufacturing method of an electronic device according to each embodiment will be described below with reference to the drawings. The following embodiments are just examples and a variety of modifications are possible within the scope of the present invention.

An electronic device in a first embodiment is a piezoelectric device including a piezoelectric element, for example. The piezoelectric device is used for a piezoelectric module. The piezoelectric module is a piezoelectric sensor, an actuator, an ultrasonic sensor, an ultrasonic generator, a pressure transducer or the like, for example.

<FIG> is a flowchart showing a manufacturing method of an electronic device in the first embodiment. <FIG> are cross-sectional views schematically showing a process of forming a release layer 11a and a functional layer 14a which will be described later on a first substrate <NUM> and a process of separating (singulating) the release layer 11a and the functional layer 14a by means of etching.

In step S101 (<FIG>), as shown in <FIG>, the release layer 11a, a crystalline thin-film layer 12a and an upper electrode layer 13a are formed on the first substrate <NUM>. Among these layers, the crystalline thin-film layer 12a and the upper electrode layer 13a are referred to collectively as the functional layer 14a. Incidentally, the functional layer 14a may also be formed of the crystalline thin-film layer 12a alone.

The first substrate <NUM> is a growth substrate (wafer) on whose front surface the crystalline thin-film layer 12a is grown epitaxially. The first substrate <NUM> is formed of silicon, silicon dioxide, sapphire or the like, for example.

The crystalline thin-film layer 12a is a crystal layer having a piezoelectric property, for example. The crystalline thin-film layer 12a is formed of, for example, a thin-film crystal such as barium titanate, lead zirconate titanate, zinc oxide, aluminum nitride or lithium tantalate, rock crystal, or the like. The thickness of the crystalline thin-film layer 12a is <NUM> to <NUM>, for example.

To obtain an excellent piezoelectric property, it is desirable to epitaxially grow the crystalline thin-film layer 12a on the first substrate <NUM> so as to form a single crystal having little lattice mismatch.

For the release layer 11a, it is desirable to select a material whose lattice constant is close to that of the crystalline thin-film layer 12a and whose etching selectivity is high, among oxide films such as magnesium oxide, zircon oxide and aluminum oxide and metals such as molybdenum and titanium, for example.

It is also possible to form a buffer layer 10a having a lattice constant between those of the first substrate <NUM> and the release layer 11a on the front surface of the first substrate <NUM> in order to reduce the lattice mismatch between the first substrate <NUM> and the release layer 11a. The buffer layer 10a may also be a stacked body formed by stacking a plurality of layers differing in the material.

In the following description, the expression "the front surface of the first substrate <NUM>" is intended to mean the front surface of the buffer layer 10a when the first substrate <NUM> has the buffer layer 10a.

The upper electrode layer 13a is formed of a metal having high electrical conductivity such as platinum, gold, silver, aluminum or copper or an alloy including two or more of these metals. The thickness of the upper electrode layer 13a is <NUM> to <NUM>, for example. Incidentally, the formation of the upper electrode layer 13a may also be executed after a transfer process onto a second substrate <NUM> which will be described later.

In the subsequent step S102 (<FIG>), as shown in <FIG>, grooves <NUM> are formed by means of photolithography or the like, by which the release layer 11a and the functional layer 14a are separated (singulated) into pieces like islands. While the buffer layer 10a is not separated in this example, it is also possible to further separate the buffer layer 10a.

The release layer 11a after being separated is referred to as a "release layer <NUM>". Similarly, the crystalline thin-film layer 12a after being separated is referred to as a "crystalline thin-film layer <NUM>", and the upper electrode layer 13a after being separated is referred to as an "upper electrode layer <NUM>". A functional layer <NUM> (referred to also as a "functional thin film") is formed by the crystalline thin-film layer <NUM> and the upper electrode layer <NUM>. Incidentally, the functional layer <NUM> may also be formed of the crystalline thin-film layer <NUM> alone.

The functional layer <NUM> has a front surface (first surface) 14f on a side opposite to the first substrate <NUM>, a back surface (second surface) 14r on a side facing the first substrate <NUM>, and side faces <NUM> as inclined surfaces formed between the front surface 14f and the back surface 14r.

While the front surface of the upper electrode layer <NUM> serves as the front surface 14f of the functional layer <NUM> in this example, the front surface of the crystalline thin-film layer <NUM> serves as the front surface 14f of the functional layer <NUM> when the functional layer <NUM> does not include the upper electrode layer <NUM>.

In this example, a two-dimensional shape (shape in a plane parallel to the front surface of the first substrate <NUM>) of the functional layer <NUM> is a circular shape (see <FIG>). However, the two-dimensional shape of the functional layer <NUM> is not limited to a circular shape but may also be a quadrangular shape (see <FIG>), for example.

<FIG> are a cross-sectional view and a plan view schematically showing a process of forming a support layer <NUM> which will be described below. In step S103 (<FIG>), the support layer <NUM> is formed from the front surface 14f of the functional layer <NUM> to the front surface of the first substrate <NUM> as shown in <FIG>. The support layer <NUM> is a part that supports the functional layer <NUM> with respect to the first substrate <NUM>.

The support layer <NUM> is deposited by means of CVD (Chemical Vapor Deposition) or the like and thereafter patterned by means of lithography, etching or the like. The support layer <NUM> is formed of a material having resistance to an etching solution used in a process of removing a release layer <NUM> which will be described later. As an example, an inorganic insulation film such as an oxide film or a nitride film is desirable for the support layer <NUM>.

The support layer <NUM> extends from the front surface of the upper electrode layer <NUM> to the front surface of the first substrate <NUM> via a side face of the crystalline thin-film layer <NUM>. In other words, the support layer <NUM> extends from the front surface 14f of the functional layer <NUM> to the front surface of the first substrate <NUM> via the side face <NUM> of the functional layer <NUM>.

As shown in <FIG>, the support layer <NUM> is provided at two positions in a <NUM>-degree positional relationship with respect to the center of the functional layer <NUM> in the circular shape. Namely, two support layers <NUM> are provided for each functional layer <NUM>.

A large proportion of the front surface of the first substrate <NUM>, a large proportion of each of side faces of the release layer <NUM>, the crystalline thin-film layer <NUM> and the upper electrode layer <NUM>, and a central region of the front surface of the upper electrode layer <NUM> are not covered by the support layer <NUM> and are exposed.

On the front surface of the upper electrode layer <NUM>, arc-shaped end parts <NUM> of the two support layers <NUM> face each other. The central region (represented by a reference character R1) of the upper electrode layer <NUM> is the exposed part. This central region is a region in which a wiring is formed in a later process.

Incidentally, the number of support layers <NUM> for one functional layer <NUM> is not limited to <NUM>. It is sufficient that one or more support layers <NUM> are provided for each functional layer <NUM>.

<FIG> is a cross-sectional view schematically showing a cross-sectional shape of the support layer <NUM>. The support layer <NUM> includes a first part <NUM> joined to the front surface of the first substrate <NUM>, a second part <NUM> joined to the side face <NUM> of the functional layer <NUM>, and a third part <NUM> joined to the front surface 14f of the functional layer <NUM>.

The first part <NUM>, the second part <NUM> and the third part <NUM> respectively have thicknesses T1, T2 and T3. The thickness T2 of the second part <NUM> is less than the thickness T1 of the first part <NUM> and less than the thickness T3 of the third part <NUM>. In other words, the support layer <NUM> is configured so that the second part <NUM> is the most likely to be fractured.

<FIG> are a cross-sectional view and a plan view schematically showing a process of forming a thin film holding layer <NUM> which will be explained next. In step S104 (<FIG>), the thin film holding layer <NUM> is formed on the functional layer <NUM> as shown in <FIG>.

The thin film holding layer <NUM> is an organic structure and is formed of a material that has resistance to the etching solution used in the process of removing the release layer <NUM> which will be described later and that can be removed by using a stripper solution different from the etching solution. As an example, a photosensitive organic resist, silicone resin or the like is desirable for the thin film holding layer <NUM>.

The thin film holding layer <NUM> is formed by depositing an organic resist or the like to cover the support layer <NUM> and the functional layer <NUM> on the first substrate <NUM> and patterning the deposited film by photolithography.

The thin film holding layer <NUM> is formed to be thicker than the functional layer <NUM>, so that the thin film holding layer <NUM> has higher bending strength and shear strength than the functional layer <NUM>. As an example, the thickness of the thin film holding layer <NUM> is <NUM> to <NUM> times the thickness of the functional layer <NUM>.

Further, the linear expansion coefficient of the thin film holding layer <NUM> is desired to be less than the linear expansion coefficient of the crystalline thin-film layer <NUM> so that the crystalline thin-film layer <NUM> does not warp toward the first substrate <NUM> in the process of removing (etching) the release layer <NUM> which will be described later.

The thin film holding layer <NUM> is formed to cover a boundary part (represented by a reference character E in <FIG>) between the front surface 14f of the functional layer <NUM> (the front surface of the upper electrode layer <NUM>) and the support layer <NUM>. With this configuration, cracking that is likely to occur in the boundary part can be prevented effectively.

Further, the area of the thin film holding layer <NUM> is smaller than the area of the front surface 14f of the functional layer <NUM>. Accordingly, the thin film holding layer <NUM> is prevented from hanging down toward the side face of the crystalline thin-film layer <NUM>.

<FIG> are cross-sectional views schematically showing a process of removing the release layer <NUM>, a process of separating the functional layer <NUM>, the support layer <NUM> and the thin film holding layer <NUM> from the first substrate <NUM>, and a process of transferring the functional layer <NUM>, the support layer <NUM> and the thin film holding layer <NUM> to the second substrate <NUM>.

In step S105 (<FIG>), the release layer <NUM> is removed by means of etching as shown in <FIG>. By this step, a gap G is formed between the functional layer <NUM> and the first substrate <NUM>, more specifically, between the crystalline thin-film layer <NUM> and the first substrate <NUM>.

The support layer <NUM> supports the functional layer <NUM> in the state of being separate from the first substrate <NUM>. The support layer <NUM> inhibits force in a shear direction from acting on the functional layer <NUM>, by which the cracking of the functional layer <NUM> is prevented.

In step S106 (<FIG>), a third substrate <NUM> as a transfer member is joined to the thin film holding layer <NUM> as shown in <FIG>. The third substrate <NUM> is formed of a hard material such as glass or silicon.

The third substrate <NUM> can be joined to the thin film holding layer <NUM> by using an adhesive sheet having a thermal release property or an ultraviolet release property, for example. It is also possible to directly join the third substrate <NUM> to the thin film holding layer <NUM> by forming the thin film holding layer <NUM> with a material having elasticity and adhesiveness (tackiness).

In step S107 (<FIG>), as shown in <FIG>, the support layer <NUM> is fractured by applying force to the third substrate <NUM> in a direction of separating from the first substrate <NUM>. The support layer <NUM> fractures in the second part <NUM> being the thinnest, while the first part <NUM> remains on the first substrate <NUM>. By this step, the functional layer <NUM>, the support layer <NUM> (more specifically, the second part <NUM> and the third part <NUM>) and the thin film holding layer <NUM> separate from the first substrate <NUM>.

In step S108 (<FIG>), as shown in <FIG>, the functional layer <NUM> held by the thin film holding layer <NUM> joined to the third substrate <NUM> is joined to the second substrate <NUM>.

On the front surface of the second substrate <NUM>, each lower electrode <NUM> has been formed in a region larger than a prospective joint region for the functional layer <NUM>. The lower electrode <NUM> is formed of a metal having high electrical conductivity such as platinum, gold, silver, aluminum or copper or an alloy including two or more of these metals. The lower electrode <NUM> has a thickness of <NUM> to <NUM>.

The lower electrode <NUM> has a smooth surface in the prospective joint region for the functional layer <NUM>, and surface roughness of the smooth surface is less than or equal to <NUM>, for example. The third substrate <NUM> and the second substrate <NUM> are positioned with each other by using alignment marks provided on the substrates.

Heating and pressing are executed in a state in which the functional layer <NUM> is in contact with the lower electrode <NUM> on the second substrate <NUM>. Accordingly, the functional layer <NUM> is joined to the lower electrode <NUM> on the second substrate <NUM> by intermolecular force.

<FIG> are a cross-sectional view and a plan view schematically showing a process of removing the thin film holding layer <NUM>.

In step S109 (<FIG>), the thin film holding layer <NUM> is removed as shown in <FIG>. The thin film holding layer <NUM> can be removed by using a stripper solution, for example. Specifically, the unit (<FIG>) including the third substrate <NUM> and the second substrate <NUM> is placed in a bath storing the stripper solution and vibration is applied thereto. Consequently, the thin film holding layer <NUM> is dissolved and removed and the third substrate <NUM> peels off.

By the removal of the thin film holding layer <NUM>, a configuration in which the crystalline thin-film layers <NUM> and the upper electrode layers <NUM> (i.e., the functional layers <NUM>) are arrayed in a matrix on the lower electrodes <NUM> on the second substrate <NUM> is obtained as shown in <FIG>. The lower electrodes <NUM> extend in a column direction (Y direction shown in <FIG>), and a plurality of crystalline thin-film layers <NUM> are arranged on each lower electrode <NUM>. The lower electrodes <NUM> constitute longitudinal wirings of the second substrate <NUM>.

By this step, piezoelectric elements <NUM> each including the crystalline thin-film layer <NUM>, the upper electrode layer <NUM> and the lower electrode <NUM> are formed. Further, a piezoelectric device as an electronic device including the second substrate <NUM> and the piezoelectric elements <NUM> (each including the crystalline thin-film layer <NUM>, the upper electrode layer <NUM> and the lower electrode <NUM>) is obtained. By forming wirings and the like on this piezoelectric device, a piezoelectric module <NUM> which will be described next is obtained.

<FIG> are a cross-sectional view and a plan view schematically showing a process of forming the wiring and the like on the second substrate <NUM>. Incidentally, <FIG> corresponds to a cross-sectional view taken along the line segment 7A - 7A shown in <FIG> is a cross-sectional view, which is different from <FIG>, taken along the line segment 7C - 7C shown in <FIG>.

In step S110 (<FIG>), the wiring and the like are formed on the second substrate <NUM> as shown in <FIG>. As an example, an interlayer insulation layer <NUM> is formed between the upper electrode layer <NUM> and a transverse wiring <NUM> which will be described later. The interlayer insulation layer <NUM> extends from the front surface of the upper electrode layer <NUM> and along the side face of the crystalline thin-film layer <NUM>. The transverse wiring <NUM> is a wiring layer extending in a row direction (X direction shown in <FIG>).

On the interlayer insulation layer <NUM>, a lead wiring <NUM> extending from the front surface of the upper electrode layer <NUM> to the transverse wiring <NUM> is formed. Further, on the interlayer insulation layer <NUM>, the aforementioned transverse wiring <NUM> is formed between adjoining crystalline thin-film layers <NUM>. Incidentally, it is also possible to form the transverse wiring <NUM> and the lead wiring <NUM> in the same process.

Parenthetically, the support layer <NUM> may be either removed in a later process or used as an interlayer insulation layer of some type.

By the above processes, the piezoelectric module <NUM> including the second substrate <NUM>, the piezoelectric elements <NUM> (each including the crystalline thin-film layer <NUM>, the upper electrode layer <NUM> and the lower electrode <NUM>), the transverse wirings <NUM>, the lead wirings <NUM> and the like is formed.

The transverse wirings <NUM> and the longitudinal wirings (lower electrodes) <NUM> on the second substrate <NUM> are connected to a not-shown driver. It is possible to drive an intended piezoelectric element <NUM> on the second substrate <NUM> by inputting a drive signal from the driver to the longitudinal wiring (lower electrode) <NUM> and the transverse wiring <NUM>. Accordingly, the piezoelectric module <NUM> can be configured as an actuator such as MEMS (Micro Electro Mechanical Systems) or an ultrasonic generator.

It is also possible to configure the piezoelectric module <NUM> as a piezoelectric sensor, an ultrasonic sensor or the like by taking advantage of the phenomenon in which pressure applied to the piezoelectric element <NUM> causes potential difference between the upper electrode layer <NUM> and the lower electrode <NUM>.

Next, the function of the first embodiment will be described below in comparison with a comparative example. <FIG> are a cross-sectional view, a plan view and a schematic diagram schematically showing a process of removing the release layer <NUM> in a manufacturing method of an electronic device in the comparative example. The manufacturing method of the electronic device in the comparative example differs from the manufacturing method of the electronic device in the first embodiment in that the removal of the release layer <NUM> is executed without using the thin film holding layer <NUM>.

As shown in <FIG>, in the process of removing the release layer <NUM>, the support layer <NUM> supports the functional layer <NUM> in the state of being separate from the first substrate <NUM>. Since the functional layer <NUM> (especially, the crystalline thin-film layer <NUM>) is thin, it is difficult to support the functional layer <NUM> with the support layer <NUM> only. Thus, there is a possibility that the cracking occurs in a central part of the functional layer <NUM> or in the vicinity of a joint part between the functional layer <NUM> and the support layer <NUM> in the process of removing the release layer <NUM> or subsequent processes.

Further, as shown in <FIG>, there is also a possibility that an outer periphery of the functional layer <NUM> hangs down. In this case, there is a possibility of occurrence of an etching defect due to blockage of entry of the etching solution for removing the release layer <NUM>, etching gas remaining under the crystalline thin-film layer <NUM>, or the like.

Such cracking of the functional layer <NUM> and the etching defect become more likely to occur as the area of the functional layer <NUM> increases and become especially remarkable as the diameter of the functional layer <NUM> exceeds <NUM>.

In contrast, in the first embodiment, the thin film holding layer <NUM> is provided on the functional layer <NUM>, and thus the shape of the functional layer <NUM> can be maintained during the process of removing the release layer <NUM> and subsequent processes. Accordingly, the cracking of the functional layer <NUM> can be prevented and the etching defect due to deformation of the functional layer <NUM> can be prevented.

Incidentally, while the thin film holding layer <NUM> covers the boundary part between the front surface 14f of the functional layer <NUM> and the support layer <NUM> in this example, this embodiment is not limited to such a configuration.

<FIG> are a cross-sectional view and a plan view schematically showing another example of the process of removing the release layer <NUM>. In the example shown in <FIG>, the third part <NUM> of the support layer <NUM> covers the top of the upper electrode layer <NUM>. The thin film holding layer <NUM> is provided on the third part <NUM> of the support layer <NUM>. Also in this case, the shape of the functional layer <NUM> is maintained by the thin film holding layer <NUM> and the support layer <NUM>, by which the cracking and the deformation of the functional layer <NUM> can be prevented.

Incidentally, in the plan view of <FIG>, the functional layer <NUM> (only the upper electrode layer <NUM> is shown in <FIG>) is in a quadrangular shape, the third part <NUM> of the support layer <NUM> (the part covering the upper electrode layer <NUM>) is also in a quadrangular shape, and two first parts <NUM> extend from the third part <NUM> in each of a leftward direction and a rightward direction in the drawing. However, shapes of the elements in this example are not limited to those shown in <FIG>. The functional layer <NUM> may be in a circular shape as shown in <FIG>. Further, the number of first parts <NUM> in each support layer <NUM> may also be any desired number. It is also possible that the first parts <NUM> of two adjoining support layers <NUM> connect to each other.

Further, as shown in <FIG>, the thin film holding layer <NUM> may be provided only on the front surface 14f of the functional layer <NUM> (the front surface of the upper electrode layer <NUM> in this case) without reaching the support layer <NUM>. Namely, it is sufficient that the thin film holding layer <NUM> is formed on at least one of the support layer <NUM> and the front surface 14f of the functional layer <NUM>.

In the above-described example, the functional layer <NUM> is formed on the first substrate <NUM> via the release layer <NUM> (steps S101 and S102) and thereafter the support layer <NUM> is formed (step S103). However, it is also possible to use the first substrate <NUM> on which the functional layer <NUM> has previously been formed via the release layer <NUM> and form the support layer <NUM> on the first substrate <NUM> from the front surface 14f of the functional layer <NUM> to the first substrate <NUM>.

As described above, the manufacturing method of the electronic device in the first embodiment includes the process of forming the support layer <NUM> from the front surface (first surface) 14f of the functional layer <NUM> (which is formed on the first substrate <NUM> via the release layer <NUM>) to the first substrate <NUM>, the process of forming the thin film holding layer <NUM> on at least one of the support layer <NUM> and the front surface 14f of the functional layer <NUM>, the process of removing the release layer <NUM> (first layer) after the thin film holding layer <NUM> is formed, the process of joining the third substrate (transfer member) <NUM> to the surface of the thin film holding layer <NUM> on the side opposite to the functional layer <NUM> after the first layer <NUM> is removed, the process of separating the functional layer <NUM>, the support layer <NUM> and the thin film holding layer <NUM> from the first substrate <NUM>, the process of transferring the functional layer <NUM>, the support layer <NUM> and the thin film holding layer <NUM> to the second substrate <NUM>, and the process of removing the thin film holding layer <NUM>. Accordingly, the cracking of the functional layer <NUM> can be prevented, and the deformation of the functional layer <NUM> and the etching defect due to the deformation can be prevented. Consequently, the manufacturing yield can be increased.

Further, since the thickness of the thin film holding layer <NUM> is greater than the thickness of the functional layer <NUM>, sufficient strength of the thin film holding layer <NUM> can be secured and the cracking or the like of the functional layer <NUM> can be prevented more effectively.

Since the area of the thin film holding layer <NUM> is smaller than the area of the front surface (first surface) 14f of the functional layer <NUM>, the thin film holding layer <NUM> does not hang down along the side face <NUM> of the functional layer <NUM>. Therefore, the etching defect caused by the blockage of the entry of the etching solution by the thin film holding layer <NUM> hanging down can be prevented.

Since the thin film holding layer <NUM> covers the boundary part between the front surface 14f of the functional layer <NUM> and the support layer <NUM>, the cracking that is likely to occur in the boundary part can be prevented effectively.

Since the support layer <NUM> is formed in a region on the front surface 14f of the functional layer <NUM> other than the central region (element formation region or electrode formation region), the formation of the wiring in the subsequent process can be executed with ease.

The support layer <NUM> includes the first part <NUM> joined to the first substrate <NUM>, the second part <NUM> joined to the side face <NUM> of the functional layer <NUM> and the third part <NUM> joined to the front surface 14f of the functional layer <NUM>. The thickness T2 of the second part <NUM> is less than the thickness T1 of the first part <NUM> and less than the thickness T3 of the third part <NUM>. Therefore, the support layer <NUM> can be surely fractured in the second part <NUM> at the time of peeling off the functional layer <NUM> from the first substrate <NUM>.

An electronic device in a second embodiment is a photoelectric conversion device including a photoelectric conversion element such as an LED (Light-Emitting Diode), for example. The photoelectric conversion device is used for a photoelectric conversion module. The photoelectric conversion module is an LED display, an image sensor or the like, for example.

<FIG> is a flowchart showing a manufacturing method of an electronic device in the second embodiment. <FIG> are cross-sectional views schematically showing a process of forming a release layer 31a and a functional layer 34a which will be described later on a first substrate <NUM> and a process of separating (singulating) the release layer 31a and the functional layer 34a by means of etching.

In step S201 (<FIG>), as shown in <FIG>, the release layer 31a, a crystalline thin-film layer 32a and a transparent electrode layer 33a are formed on the first substrate <NUM>. Among these layers, the crystalline thin-film layer 32a and the transparent electrode layer 33a are referred to collectively as the functional layer 34a. Incidentally, the functional layer 34a may also be formed of the crystalline thin-film layer 32a alone.

The first substrate <NUM> is a growth substrate (wafer) on whose front surface the crystalline thin-film layer 32a is grown epitaxially. The first substrate <NUM> is formed of gallium arsenide, indium phosphide, silicon, sapphire or the like, for example. In cases where the first substrate <NUM> is formed of silicon or sapphire, it is desirable to form a buffer layer on the front surface of the substrate.

The crystalline thin-film layer 32a is a semiconductor layer having a light emitting property or a light receiving property. Specifically, the crystalline thin-film layer 32a can be a stacked body formed by stacking a group III-V compound semiconductor containing gallium, aluminum, indium, arsenic, nitrogen, phosphorus, or the like, a P-type semiconductor layer, an active layer, an etching stop layer, an N-type semiconductor layer, and the like. The thickness of the crystalline thin-film layer 32a is <NUM> to <NUM>, for example.

To obtain an excellent light emitting property, it is desirable to epitaxially grow the crystalline thin-film layer 32a on the first substrate <NUM> so as to form a single crystal having little lattice mismatch.

For the release layer 31a, it is desirable to select a material whose lattice constant is close to that of the crystalline thin-film layer 32a and whose etching selectivity is high, among materials such as aluminum arsenide, indium gallium arsenide, indium aluminum arsenide, and aluminum nitride, for example.

While the release layer 31a is a layer removed in a removal process which will be described later, the release layer 31a also plays a role of a buffer layer. It is also possible to form a buffer layer, which has a lattice constant between those of the first substrate <NUM> and the release layer 31a, on the front surface of the first substrate <NUM>.

The transparent electrode layer 33a is formed of tin-doped indium oxide (ITO (Indium Tin Oxide)), fluorine-doped indium oxide, or the like. The transparent electrode layer 33a has transmittance higher than or equal to <NUM> % for the dominant wavelength used and has electrical conductivity. The thickness of the transparent electrode layer 33a is <NUM> to <NUM>, for example. Incidentally, the formation of the transparent electrode layer 33a may also be executed after a transfer process onto a second substrate <NUM> which will be described later.

In the subsequent step S202 (<FIG>), as shown in <FIG>, grooves <NUM> are formed by means of photolithography or the like, by which the release layer 31a and the functional layer 34a are separated (singulated) into pieces like islands. In the second embodiment, the separation is carried out so that each island includes a plurality of element formation regions.

The release layer 31a after being separated is referred to as a "release layer <NUM>". Similarly, the crystalline thin-film layer 32a after being separated is referred to as a "crystalline thin-film layer <NUM>", and the transparent electrode layer 33a after being separated is referred to as a "transparent electrode layer <NUM>". A functional layer <NUM> (referred to also as a "functional thin film") is formed by the crystalline thin-film layer <NUM> and the transparent electrode layer <NUM>. Incidentally, the functional layer <NUM> may also be formed of the crystalline thin-film layer <NUM> alone.

Since the functional layer <NUM> includes a plurality of element formation regions, the functional layer <NUM> has a relatively large area of <NUM> to <NUM>, for example.

The functional layer <NUM> has a front surface (first surface) 34f on a side opposite to the first substrate <NUM>, a back surface (second surface) 34r on a side facing the first substrate <NUM>, and side faces <NUM> as inclined surfaces formed between the front surface 34f and the back surface 34r.

While the front surface of the transparent electrode layer <NUM> serves as the front surface 34f of the functional layer <NUM> in this example, the front surface of the crystalline thin-film layer <NUM> serves as the front surface 34f of the functional layer <NUM> when the functional layer <NUM> does not include the transparent electrode layer <NUM>.

In this example, the two-dimensional shape (shape in a plane parallel to the front surface of the first substrate <NUM>) of the functional layer <NUM> is a quadrangular shape (see <FIG>). However, the two-dimensional shape of the functional layer <NUM> is not limited to a quadrangular shape but may also be a circular shape, for example.

<FIG> are a cross-sectional view and a plan view schematically showing a process of forming a support layer <NUM> which will be described below. In step S203 (<FIG>), the support layer <NUM> is formed from the front surface 34f of the functional layer <NUM> to the front surface of the first substrate <NUM> as shown in <FIG>. The support layer <NUM> is a part that supports the functional layer <NUM> with respect to the first substrate <NUM>.

The support layer <NUM> is deposited by means of CVD (Chemical Vapor Deposition) or the like and thereafter patterned by means of lithography, etching or the like. The support layer <NUM> is formed of a material having resistance to the etching solution used in a process of removing the release layer <NUM> which will be described later. As an example, an inorganic insulation film such as an oxide film or a nitride film is desirable for the support layer <NUM>.

The support layer <NUM> extends from the front surface of the transparent electrode layer <NUM> to the front surface of the first substrate <NUM> via a side face of the crystalline thin-film layer <NUM>. In other words, the support layer <NUM> extends from the front surface 34f of the functional layer <NUM> to the front surface of the first substrate <NUM> via the side face <NUM> of the functional layer <NUM>.

As shown in <FIG>, the support layer <NUM> is provided at two positions on each of four sides of the functional layer <NUM> in the quadrangular shape. Namely, eight support layers <NUM> are provided for each functional layer <NUM>.

A large proportion of the front surface of the first substrate <NUM>, a large proportion of each of side faces of the release layer <NUM>, the crystalline thin-film layer <NUM> and the transparent electrode layer <NUM>, and a central region (represented by a reference character R2) of the front surface of the transparent electrode layer <NUM> are not covered by the support layer <NUM> and are exposed. The central region of the transparent electrode layer <NUM> is a region in which a wiring is formed in a subsequent process.

<FIG> is a cross-sectional view schematically showing the cross-sectional shape of the support layer <NUM>. The support layer <NUM> includes a first part <NUM> joined to the front surface of the first substrate <NUM>, a second part <NUM> joined to the side face <NUM> of the functional layer <NUM>, and a third part <NUM> joined to the front surface 34f of the functional layer <NUM>.

<FIG> are a cross-sectional view and a plan view schematically showing a process of forming a thin film holding layer <NUM> which will be explained next. In step S204 (<FIG>), the thin film holding layer <NUM> is formed on the functional layer <NUM> as shown in <FIG>.

The thin film holding layer <NUM> is formed to cover a boundary part between the front surface 34f of the functional layer <NUM> (the front surface of the transparent electrode layer <NUM>) and the support layer <NUM>. With this configuration, the cracking that is likely to occur in the boundary part can be prevented effectively.

Further, the area of the thin film holding layer <NUM> is smaller than the area of the front surface 34f of the functional layer <NUM>. Accordingly, the thin film holding layer <NUM> is prevented from hanging down toward the side face of the crystalline thin-film layer <NUM>.

In step S205 (<FIG>), the release layer <NUM> is removed by means of etching. By this step, a gap G is formed between the functional layer <NUM> and the first substrate <NUM>, more specifically, between the crystalline thin-film layer <NUM> and the first substrate <NUM>.

The support layer <NUM> supports the functional layer <NUM> in the state of being separate from the first substrate <NUM>. The support layer <NUM> inhibits force in the shear direction from acting on the functional layer <NUM>, by which the cracking of the functional layer <NUM> is prevented.

In step S206 (<FIG>), a third substrate <NUM> as the transfer member is joined to the thin film holding layer <NUM> as shown in <FIG>. The third substrate <NUM> is formed of a hard material such as glass or silicon.

The third substrate <NUM> can be joined to the thin film holding layer <NUM> by using an adhesive sheet having the thermal release property or the ultraviolet release property, for example. It is also possible to directly join the third substrate <NUM> to the thin film holding layer <NUM> by forming the thin film holding layer <NUM> with a material having elasticity and adhesiveness (tackiness).

In step S207 (<FIG>), as shown in <FIG>, the support layer <NUM> is fractured by applying force to the third substrate <NUM> in the direction of separating from the first substrate <NUM>. The support layer <NUM> fractures in the second part <NUM> being the thinnest, while the first part <NUM> remains on the first substrate <NUM>. By this step, the functional layer <NUM>, the support layer <NUM> (more specifically, the second part <NUM> and the third part <NUM>) and the thin film holding layer <NUM> separate from the first substrate <NUM>.

In step S208 (<FIG>), as shown in <FIG>, the functional layer <NUM> held by the thin film holding layer <NUM> joined to the third substrate <NUM> is joined to the second substrate <NUM>.

The second substrate <NUM> has a smooth surface in the prospective joint region for the functional layer <NUM>, and the surface roughness of the smooth surface is less than or equal to <NUM>, for example. The third substrate <NUM> and the second substrate <NUM> are positioned with each other by using alignment marks provided on the substrates.

Heating and pressing are executed in a state in which the functional layer <NUM> is in contact with the front surface of the second substrate <NUM>. Accordingly, the functional layer <NUM> is joined to the front surface of the second substrate <NUM> by intermolecular force.

In step S209 (<FIG>), the thin film holding layer <NUM> is removed as shown in <FIG>. The thin film holding layer <NUM> can be removed by using a stripper solution, for example. Specifically, the unit (<FIG>) including the third substrate <NUM> and the second substrate <NUM> is placed in a bath storing the stripper solution and vibration is applied thereto. Consequently, the thin film holding layer <NUM> is dissolved and removed and the third substrate <NUM> peels off.

By the removal of the thin film holding layer <NUM>, a configuration in which the crystalline thin-film layer <NUM> and the transparent electrode layer <NUM> are (i.e., the functional layer <NUM> is) provided on the second substrate <NUM> is obtained as shown in <FIG>.

<FIG> is a cross-sectional view schematically showing a process of separating the functional layer <NUM> into pieces for respective elements. In step S210 (<FIG>), as shown in <FIG>, the P-type semiconductor layer of the crystalline thin-film layer <NUM> of the functional layer <NUM> is patterned by means of first stage etching. In this stage, the support layer <NUM> is removed. In other words, a part of the functional layer <NUM> and the support layer <NUM> are removed.

In the subsequent step S211, by means of second stage etching, the N-type semiconductor layer of the crystalline thin-film layer <NUM> of the functional layer <NUM> is patterned, by which cathode surfaces <NUM> are formed and the functional layer <NUM> is separated into a plurality of islands (i.e., element separation).

By this step, LED elements <NUM> each including the crystalline thin-film layer <NUM> and the transparent electrode layer <NUM> and patterned as an individual element are formed. Further, a photoelectric conversion device as an electronic device including the second substrate <NUM> and the LED elements <NUM> (including the crystalline thin-film layers <NUM> and the transparent electrode layers <NUM>) is obtained. By forming the wirings and the like on the photoelectric conversion device, a photoelectric conversion module <NUM> which will be described next is obtained.

<FIG> are a cross-sectional view and a plan view schematically showing a process of forming the wiring and the like on the functional layer <NUM> on the second substrate <NUM>. Incidentally, <FIG> corresponds to a cross-sectional view taken along the line segment 17A - 17A shown in <FIG>. Further, <FIG> is a cross-sectional view different from <FIG>, as a cross-sectional view taken along the line segment 17C - 17C shown in <FIG>.

In step S212 (<FIG>), the wiring and the like are formed on the second substrate <NUM> as shown in <FIG>. As an example, a longitudinal wiring <NUM> extending in the column direction (Y direction in <FIG>) is formed on the front surface of the second substrate <NUM>.

An interlayer insulation layer <NUM> is formed from the cathode surface <NUM> to the side face of the crystalline thin-film layer <NUM>. On this interlayer insulation layer <NUM>, a lead wiring <NUM> is formed so as to connect the cathode surface <NUM> and the longitudinal wiring <NUM>.

Further, as shown in <FIG>, an interlayer insulation layer <NUM> is formed so as to extend from the front surface of the transparent electrode layer <NUM> to the second substrate <NUM> via the side face of the crystalline thin-film layer <NUM>. On this interlayer insulation layer <NUM>, a transverse wiring <NUM> extending in the row direction (X direction in <FIG>) is formed between adjoining crystalline thin-film layers <NUM>. Furthermore, a lead wiring <NUM> is formed so as to connect the transparent electrode layer <NUM> and the transverse wiring <NUM>.

By the above-described processes, the photoelectric conversion module <NUM> including the second substrate <NUM>, the LED elements <NUM> (including the crystalline thin-film layers <NUM> and the transparent electrode layers <NUM>), the wirings <NUM> and <NUM>, the lead wirings <NUM> and <NUM>, and the like is formed.

The transverse wiring <NUM> and the longitudinal wiring <NUM> on the second substrate <NUM> are connected to a not-shown driver. It is possible to drive an intended LED element <NUM> on the second substrate <NUM> by inputting a drive signal from the driver to the longitudinal wiring <NUM> and the transverse wiring <NUM>. Accordingly, the photoelectric conversion module <NUM> can be configured as an LED display, for example.

An LED array device can be employed as the light source of a liquid crystal display having a high dynamic range function by providing each LED element <NUM> with a current regulation circuit. Although an example in which the LED elements <NUM> are arrayed in a <NUM> × <NUM> matrix (<NUM> rows by <NUM> columns) is shown in <FIG> in order to clearly illustrate the configuration, a high-resolution micro-LED display can be formed by arraying the LED elements <NUM> in a <NUM> × <NUM> matrix, for example.

Further, the second substrate <NUM> may be a silicon substrate or a thin-film transistor substrate, on which an active matrix CMOS (Complementary Metal Oxide Semiconductor) circuit is formed. In this case, a microdisplay can be produced by connecting active elements and electrodes on the second substrate <NUM>.

Furthermore, while the LED element <NUM> in this example is a light-emitting element that emits light corresponding to applied voltage, the LED element <NUM> may also be used as a light-receiving element that outputs voltage corresponding to incident light. Namely, photoelectric conversion elements each including the LED element <NUM> can be configured as an image sensor, for example.

Incidentally, while the thin film holding layer <NUM> in this example covers the boundary part between the front surface 34f of the functional layer <NUM> and the support layer <NUM>, it is sufficient that the thin film holding layer <NUM> is formed on at least one of the support layer <NUM> and the front surface 34f of the functional layer <NUM> as described in the first embodiment. Further, examples of the arrangement of the thin film holding layer <NUM> shown in <FIG> in the first embodiment can be applied to the arrangement of the thin film holding layer <NUM> in the second embodiment.

In this example, the functional layer <NUM> is formed on the first substrate <NUM> via the release layer <NUM> (steps S201 and S202) and thereafter the support layer <NUM> is formed (step S203). However, it is also possible to use the first substrate <NUM> on which the functional layer <NUM> has previously been formed via the release layer <NUM> and form the support layer <NUM> on the first substrate <NUM> from the front surface 34f of the functional layer <NUM> to the first substrate <NUM>.

As described above, the manufacturing method of the electronic device in the second embodiment includes the process of forming the support layer <NUM> from the front surface (first surface) 14f of the functional layer <NUM> (which is formed on the first substrate <NUM> via the release layer <NUM>) to the first substrate <NUM>, the process of forming the thin film holding layer <NUM> on at least one of the support layer <NUM> and the front surface 34f of the functional layer <NUM>, the process of removing the release layer <NUM> (first layer) after the thin film holding layer <NUM> is formed, the process of joining the third substrate (transfer member) <NUM> to the surface of the thin film holding layer <NUM> on the side opposite to the functional layer <NUM> after the first layer <NUM> is removed, the process of separating the functional layer <NUM>, the support layer <NUM> and the thin film holding layer <NUM> from the first substrate <NUM>, the process of transferring the functional layer <NUM>, the support layer <NUM> and the thin film holding layer <NUM> to the second substrate <NUM>, and the process of removing the thin film holding layer <NUM>. Accordingly, the cracking of the functional layer <NUM> can be prevented, and the deformation of the functional layer <NUM> and the etching defect due to the deformation can be prevented. Consequently, the manufacturing yield can be increased.

Especially, in the manufacturing processes in which the functional layer <NUM> having a large area is peeled off from the first substrate <NUM> and transferred to the second substrate <NUM>, the prevention of the cracking and deformation of the functional layer <NUM> has significant effect in improving the manufacturing yield. Further, since the transfer of the functional layer <NUM> having a large area becomes possible, it becomes possible to form a great number of LED elements <NUM> by separating the functional layer <NUM> into pieces by means of etching or the like.

Since the area of the thin film holding layer <NUM> is smaller than the area of the front surface (first surface) 34f of the functional layer <NUM>, the etching defect caused by the hanging down of the thin film holding layer <NUM> along the side face <NUM> of the functional layer <NUM> can be prevented.

Since the thin film holding layer <NUM> covers the boundary part between the front surface 34f of the functional layer <NUM> and the support layer <NUM>, the cracking that is likely to occur in the boundary part can be prevented effectively.

Since the support layer <NUM> is formed in a region on the front surface 34f of the functional layer <NUM> other than the central region (element formation region or electrode formation region), the formation of the wiring in a subsequent process can be executed with ease.

The support layer <NUM> includes the first part <NUM> joined to the first substrate <NUM>, the second part <NUM> joined to the side face <NUM> of the functional layer <NUM> and the third part <NUM> joined to the front surface 34f of the functional layer <NUM>. The thickness T2 of the second part <NUM> is less than the thickness T1 of the first part <NUM> and less than the thickness T3 of the third part <NUM>. Therefore, the support layer <NUM> can be surely fractured in the second part <NUM> at the time of peeling off the functional layer <NUM> from the first substrate <NUM>.

An electronic device in a third embodiment is the piezoelectric device described in the first embodiment. However, the electronic device can also be the photoelectric conversion device described in the second embodiment. A manufacturing method of the electronic device in the third embodiment differs from that in the first embodiment is that functional layers <NUM> on the first substrate <NUM> are selectively peeled off (separated) and transferred.

<FIG> is a flowchart showing the manufacturing method of the electronic device in the third embodiment. <FIG> are cross-sectional views schematically showing a process of removing the release layer <NUM>, a process of joining a third substrate <NUM> to the thin film holding layer <NUM>, and a process of peeling off the functional layer <NUM> from the first substrate <NUM>.

Steps S301 to S305 (<FIG>) are the same as the steps S101 to S105 (<FIG>) in the first embodiment. Namely, as shown in <FIG>, each functional layer <NUM> is supported by the support layer <NUM> in the state of being separate from the first substrate <NUM>. Further, the thin film holding layer <NUM> is provided on the front surface 14f of the functional layer <NUM> and the support layer <NUM>.

In step S306 (<FIG>), the third substrate <NUM> having concaves and convexes is used as the transfer member. The third substrate <NUM> includes convex parts <NUM> projecting towards the first substrate <NUM>. The interval between adjoining convex parts <NUM> of the third substrate <NUM> is wider than the interval between functional layers <NUM> adjoining each other on the first substrate <NUM>.

In the example shown in <FIG>, the convex parts <NUM> of the third substrate <NUM> respectively face the thin film holding layers <NUM> on alternate functional layers <NUM> on the first substrate <NUM>. A concave part <NUM> is formed between adjoining convex parts <NUM> of the third substrate <NUM>.

When the third substrate <NUM> is moved closer to the first substrate <NUM>, each convex part <NUM> of the third substrate <NUM> is joined to a thin film holding layer <NUM> facing the convex part <NUM> among the thin film holding layers <NUM> on the functional layers <NUM> on the first substrate <NUM>. The method of joining the third substrate <NUM> to the thin film holding layers <NUM> is as described in the first embodiment.

In step S307 (<FIG>), force is applied to the third substrate <NUM> in the direction away from the first substrate <NUM> as shown in <FIG>. The functional layers <NUM> under the thin film holding layers <NUM> joined to the convex parts <NUM> of the third substrate <NUM> are separated from the first substrate <NUM> by the fracture of the support layers <NUM>.

On the other hand, the thin film holding layers <NUM> facing the concave parts <NUM> of the third substrate <NUM> and the functional layers <NUM> and the support layers <NUM> under such thin film holding layers <NUM> remain on the first substrate <NUM>. Namely, selective peeling (i.e., pickup) of functional layers <NUM> is executed.

<FIG> are cross-sectional views schematically showing a process of transferring the functional layer <NUM>, the support layer <NUM> and the thin film holding layer <NUM> to the second substrate <NUM> and a process of removing the thin film holding layer <NUM>.

In step S308 (<FIG>), as shown in <FIG>, the functional layer <NUM> held by the thin film holding layer <NUM> joined to the third substrate <NUM> is joined to the second substrate <NUM>. On the front surface of the second substrate <NUM>, the lower electrodes <NUM> described in the first embodiment have been formed. The functional layer <NUM> and the lower electrode <NUM> on the second substrate <NUM> are joined together by intermolecular force as described in the first embodiment.

In step S309 (<FIG>), the thin film holding layer <NUM> is removed as shown in <FIG>. The method of peeling off the thin film holding layer <NUM> is as described in the first embodiment.

In step S310 (<FIG>), the lead wiring <NUM> and the like are formed on the functional layer <NUM> on the second substrate <NUM> similarly to the step S110 in the first embodiment. By this step, the piezoelectric elements <NUM> and a piezoelectric device including the piezoelectric elements <NUM> are formed. Further, by forming the wirings and the like on the second substrate <NUM>, the piezoelectric module <NUM> (see <FIG> explained earlier) is formed.

In step S311 (<FIG>), it is judged whether or not a functional layer <NUM> to be transferred remains on the first substrate <NUM>. If no functional layer <NUM> to be transferred remains on the first substrate <NUM>, the process is ended. If a functional layer <NUM> to be transferred remains on the first substrate <NUM>, the process advances to step S312.

<FIG> are cross-sectional views schematically showing a process of joining the third substrate <NUM> to the thin film holding layers <NUM> on the functional layers <NUM> remaining on the first substrate <NUM> and a process of peeling off the functional layers <NUM> from the first substrate <NUM>.

In step S312 (<FIG>), as shown in <FIG>, the convex parts <NUM> of the third substrate <NUM> are placed to respectively face the thin film holding layers <NUM> on the functional layers <NUM> remaining on the first substrate <NUM>, and the thin film holding layers <NUM> on the functional layers <NUM> and the convex parts <NUM> of the third substrate <NUM> are joined together. The method of joining the third substrate <NUM> and the thin film holding layers <NUM> is the same as the step S306.

Incidentally, in this step S312, the third substrate <NUM> used in the step S306 may be reused. In this case, the convex parts <NUM> can be joined to the thin film holding layers <NUM> on the functional layers <NUM> other than those in the step S306 by shifting the alignment position of the third substrate <NUM> with respect to the first substrate <NUM>.

In step S313 (<FIG>), as shown in <FIG>, force is applied to the third substrate <NUM> in the direction away from the first substrate <NUM>. The functional layers <NUM> under the thin film holding layers <NUM> joined to the convex parts <NUM> of the third substrate <NUM> are separated from the first substrate <NUM> by the fracture of the support layers <NUM>.

<FIG> are cross-sectional views schematically showing a process of transferring the functional layer <NUM>, the support layer <NUM> and the thin film holding layer <NUM> to a second substrate <NUM> and a process of removing the thin film holding layer <NUM>.

In step S314 (<FIG>), as shown in <FIG>, the functional layer <NUM> held by the thin film holding layer <NUM> joined to the third substrate <NUM> is joined to a different second substrate <NUM>. While the second substrate <NUM> is a substrate different from the second substrate <NUM>, the second substrate <NUM> is configured in the same way as the second substrate <NUM>.

On the front surface of the second substrate <NUM>, lower electrodes <NUM> which are the same as the lower electrodes <NUM> on the second substrate <NUM> have been formed. The functional layer <NUM> and the lower electrode <NUM> on the second substrate <NUM> are joined together by intermolecular force as described in the first embodiment.

In step S315 (<FIG>), the thin film holding layer <NUM> is removed as shown in <FIG>. The method of peeling off the thin film holding layer <NUM> is as described in the first embodiment.

By this step, piezoelectric elements <NUM> each including the crystalline thin-film layer <NUM>, the upper electrode layer <NUM> and the lower electrode <NUM> are formed. Further, a piezoelectric device as an electronic device including the second substrate <NUM>, the crystalline thin-film layers <NUM>, the upper electrode layers <NUM> and the lower electrodes <NUM> is obtained. By providing this piezoelectric device with the wirings and the like, a piezoelectric module <NUM> which will be described next is obtained.

In step S316 (<FIG>), a lead wiring <NUM> and the like are formed on the second substrate <NUM> similarly to the step S310 described earlier.

<FIG> is a plan view schematically showing a process of forming wirings and the like on the second substrate <NUM>. An interlayer insulation layer <NUM> extending along the side face of the crystalline thin-film layer <NUM> from the front surface of the upper electrode layer <NUM> is formed between the upper electrode layer <NUM> and transverse wiring <NUM> which will be described below. The transverse wiring <NUM> is a wiring layer extending in the row direction (X direction in <FIG>). On the interlayer insulation layer <NUM>, the lead wiring <NUM> extending from the front surface of the upper electrode layer <NUM> to the transverse wiring <NUM> is formed.

By the above-described processes, the piezoelectric module <NUM> including the second substrate <NUM>, the piezoelectric elements <NUM> (each including the crystalline thin-film layer <NUM>, the upper electrode layer <NUM> and the lower electrode <NUM>), the transverse wirings <NUM>, the lead wirings <NUM> and the like is formed.

Further, as shown in <FIG>, it is also possible to further mount a sensor <NUM>, a micro-IC (Integrated Circuit) <NUM> and the like, for example, on the second substrate <NUM> and connect these components to the transverse wiring <NUM>. The sensor <NUM> and the micro-IC <NUM> can be mounted by flip-chip bonding. Alternatively, in cases where the sensor <NUM> and the micro-IC <NUM> are formed of crystalline thin films, it is also possible to grow the sensor <NUM> and the micro-IC <NUM> on a growth substrate similarly to the aforementioned crystalline thin-film layer <NUM> and join the sensor <NUM> and the micro-IC <NUM> to the second substrate <NUM>.

Incidentally, while the case where the selective peeling (pickup) of functional layers <NUM> from the first substrate <NUM> and the joining of the functional layers <NUM> to a different substrate are executed twice has been described here, the selective peeling (pickup) and the joining may be executed three times or more. Further, examples of the arrangement of the thin film holding layer <NUM> shown in <FIG> in the first embodiment can be applied to the arrangement of the thin film holding layer <NUM> in the third embodiment.

Except for the above-described features, the manufacturing method of the electronic device in the third embodiment is the same as the manufacturing method of the electronic device in the first embodiment.

As described above, in the third embodiment, by using the third substrate <NUM> as the transfer member having a concave/convex shape, the functional layers <NUM> on the first substrate <NUM> are selectively peeled off and transferred to the second substrate <NUM>. Therefore, it is possible to form the functional layers <NUM> at high density on the first substrate <NUM> and transfer the functional layers <NUM> to a different substrate (the second substrate <NUM>, the second substrate <NUM> or the like) at an arrangement pitch adapted to the purpose. Accordingly, wasting of expensive crystalline thin-film layers <NUM> can be eliminated and the manufacturing cost can be reduced.

Further, since the thin film holding layers <NUM> have previously been formed on all of the functional layers <NUM> on the first substrate <NUM> and all of the release layers <NUM> on the first substrate <NUM> have been removed, it is unnecessary to execute the formation of the thin film holding layer <NUM> and the removal of the release layer <NUM> upon each pickup. Therefore, the manufacturing process can be shortened.

While the description in the above first to third embodiments has been given of the piezoelectric device and the photoelectric conversion device as examples of the electronic device, the first to third embodiments are not limited to manufacturing methods of the piezoelectric device and the photoelectric conversion device but are applicable to manufacturing methods of various types of electronic devices including switching elements, power devices and the like, for example.

While preferred embodiments have been described specifically above, the present disclosure is not limited to the above-described embodiments and a variety of improvement or modification is possible.

The present invention is applicable to manufacturing methods of electronic devices such as piezoelectric devices, photoelectric conversion devices, switching elements and power devices.

Claim 1:
A manufacturing method of an electronic device, comprising:
a process of forming a support layer (<NUM>, <NUM>) that is provided to extend from a first surface (14f, 34f) of a functional layer (<NUM>, <NUM>) formed on a first substrate (<NUM>, <NUM>) via a first layer (<NUM>, <NUM>), as a surface on a side opposite to the first substrate (<NUM>, <NUM>), to the first substrate (<NUM>, <NUM>) and supports the functional layer (<NUM>, <NUM>) with respect to the first substrate (<NUM>, <NUM>);
a process of forming a thin film holding layer (<NUM>, <NUM>) on at least one of the support layer (<NUM>, <NUM>) and the first surface (14f, 34f) of the functional layer (<NUM>, <NUM>);
a process of removing the first layer (<NUM>, <NUM>) after the thin film holding layer (<NUM>, <NUM>) is formed;
a process of joining a transfer member (<NUM>, <NUM>, <NUM>) to a surface of the thin film holding layer (<NUM>, <NUM>) on a side opposite to the functional layer (<NUM>, <NUM>) after the first layer (<NUM>, <NUM>) is removed;
a process of separating the functional layer (<NUM>, <NUM>), the support layer (<NUM>, <NUM>) and the thin film holding layer (<NUM>, <NUM>) from the first substrate (<NUM>, <NUM>);
a process of transferring the functional layer (<NUM>, <NUM>), the support layer (<NUM>, <NUM>) and the thin film holding layer (<NUM>, <NUM>) to a second substrate (<NUM>, <NUM>, <NUM>) different from the first substrate (<NUM>, <NUM>); and
a process of removing the thin film holding layer (<NUM>, <NUM>).