Method of using an adhesive for temperature control during plasma processing

Provided is a plasma processing method and apparatus and a tray for plasma processing, which are able to improve temperature controllability of a substrate. If a vacuum chamber is evacuated by a pump while introducing a specified gas by a gas supply unit into the vacuum chamber and a high-frequency power is applied by a coil use high-frequency power supply to a coil while maintaining an interior of the vacuum chamber at a specified pressure, then plasma is generated in the vacuum chamber, and a substrate placed on a substrate electrode can be subjected to plasma processing. At this time, by providing an adhesive sheet between the substrate electrode and the substrate, temperature controllability of the substrate can be improved.

BACKGROUND OF THE INVENTION

The present invention relates to a plasma processing method and apparatus and a tray for plasma processing to be utilized for manufacturing electronic devices, micro machines (MEMS: Micro Electromechanical Systems), boards for mounting components, and the like.

FIG. 19shows one example of a generic parallel plate type plasma processing apparatus.

Referring toFIG. 19, if a vacuum chamber201is evacuated by a pump203, as an exhauster, while introducing a specified gas by a gas supply unit202into the vacuum chamber201and high-frequency power of 13.56 MHz is applied to a substrate electrode206by a substrate electrode high-frequency power supply210while maintaining an interior of the vacuum chamber201at a specified pressure by a pressure-regulating valve204, then plasma is generated in the vacuum chamber201, and a substrate209placed on the substrate electrode206can be subjected to plasma processing of etching, deposition, surface reforming, or the like. Turbo-molecular pump203and an exhaust port211are disposed just under the substrate electrode206, and the pressure-regulating valve204is an up-and-down valve disposed just under the substrate electrode206and just over the turbo-molecular pump203. The substrate electrode206is fixed to the vacuum vessel201with four props212. Moreover, an opposite electrode241is provided oppositely to the substrate electrode206.

As another plasma processing apparatus, there is a plasma processing apparatus of a high-frequency induction system for generating plasma in a vacuum vessel by applying high-frequency power to a coil. The plasma processing apparatus of this system, which generates plasma by generating a high-frequency magnetic field in the vacuum vessel and accelerating electrons by generating an inductive electric field inside the vacuum vessel by its high-frequency magnetic field, is able to generate plasma of a density higher than parallel plate type plasma.

FIG. 20shows one example of this construction. Referring toFIG. 20, by evacuating a vacuum chamber201by a turbo-molecular pump203, as an exhauster, while introducing a specified gas from a gas supply unit202into the vacuum vessel201and by applying high-frequency power of 13.56 MHz to a coil provided along a dielectric plate207, opposite to a substrate electrode206, by a coil use high-frequency power supply205while maintaining an interior of the vacuum vessel201at a specified pressure by a pressure-regulating valve204, inductive-coupling type plasma is generated in the vacuum vessel201, and a substrate209placed on the substrate electrode206can be subjected to plasma processing.

There is also provided a substrate-electrode use high-frequency power supply210for supplying high-frequency power to the substrate electrode206, thereby making it possible to control ion energy that reaches the substrate209. The turbo-molecular pump203and the exhaust port211are disposed just under the substrate electrode206, and the pressure-regulating valve204is an up-and-down valve disposed just under the substrate electrode206and just over the turbo-molecular pump203. The substrate electrode206is fixed to the vacuum vessel201with four props212.

Up to now, various materials have been used as surface material of the substrate electrode. Besides metals such as aluminum and stainless steel, there have been an example in which only a part of a surface of a substrate electrode is covered with an insulating layer (hard alumite), and only the insulating layer is brought into contact with a substrate as disclosed in U.S. Pat. No. 2,758,755, an example in which a substrate electrode portion to be brought into contact with a substrate is covered with a dielectric film (vinyl chloride, Teflon (the registered trademark of U.S. Dupont of Polytetrafluoroethylene resin mold), or polyimide) as disclosed in Japanese Laid-Open Patent Publication No. 2-155230, an example in which a substrate electrode portion to be brought into contact with a substrate is covered with a dielectric film constructed of at least one of vinyl chloride, Teflon, and polyimide, and a self-bias voltage of the substrate electrode is monitored to detect damage of the dielectric film as disclosed in U.S. Pat. No. 3,010,683, and so on. As described above, if a dielectric layer is provided between the substrate and the substrate electrode, there is an effect of reducing charge-up damage.

There is another method for improving thermal conduction of a substrate and a substrate electrode by covering a surface of the substrate electrode with a ceramic layer and applying a DC voltage to a DC electrode buried in the ceramic layer for suction of the substrate onto the substrate electrode surface with an electrostatic force, or for pressing of the substrate against the substrate electrode by a clamp ring. There is also a method for improving thermal conduction of a substrate and a substrate electrode by supplying gas (helium or the like), which becomes a thermal medium, between the substrate and the substrate electrode.

However, the aforementioned conventional system has had an issue in that, if it has been attempted to process a thin soft substrate (resin sheet, for example), a temperature of the substrate has disadvantageously been raised by plasma exposure.

This is attributed to the fact that heat exchange between the substrate and the substrate electrode becomes insufficient in a vacuum in addition to a small thermal capacity of the substrate. If it is attempted to suck the substrate onto the substrate electrode surface with an electrostatic force, then a direct current scarcely flows through a dielectric substrate, and the suction cannot take effect. Moreover, if gas that becomes a thermal medium is supplied between the substrate and the substrate electrode with the substrate pressed against the substrate electrode by a clamp ring, then the substrate is significantly deformed because the substrate is thin and soft. This not only impairs uniformity of processing but also possibly generates abnormal discharge in a space formed between the substrate and the substrate electrode, thereby lacking practicability.

Moreover, if gas that becomes a thermal medium is supplied between the substrate and the substrate electrode when the substrate is large, thin, hard, and easy to break (silicon, glass, ceramics, or the like) in the conventional system, then the substrate significantly deforms because the substrate is thin, and the substrate sometimes breaks. Particularly, when a substrate thickness is not greater than 1 mm and an area is not smaller than 0.1 m2, the aforementioned issue sometimes occurs.

SUMMARY OF THE INVENTION

In view of the aforementioned conventional issues, it is an object of the present invention to provide a plasma processing method and apparatus and a tray for plasma processing, which are able to improve temperature controllability of a substrate.

In order to achieve the aforementioned object, the present invention is constructed as follows.

According to a first aspect of the present invention, there is provided a plasma processing method comprising:

evacuating an interior of a vacuum chamber and supplying gas into the vacuum chamber, and then generating plasma in the vacuum chamber while controlling the interior of the vacuum chamber to be at a specified pressure; and

processing a substrate or a film on a substrate placed on a substrate electrode in the vacuum chamber while performing heat exchange between the substrate and the substrate electrode via an adhesive sheet disposed between the substrate electrode and the substrate.

According to a second aspect of the present invention, there is provided a plasma processing method comprising:

evacuating an interior of a vacuum chamber and supplying gas into the vacuum chamber, and then generating plasma in the vacuum chamber while controlling the interior of the vacuum chamber to be at a specified pressure; and

processing a substrate or a film on a substrate on a tray placed on a substrate electrode in the vacuum chamber while performing heat exchange between the tray and the substrate via an adhesive sheet disposed between the tray and the substrate.

According to a third aspect of the present invention, there is provided the plasma processing method as defined in the second aspect, wherein the substrate or the film on the substrate is processed while performing heat exchange between the substrate electrode and the tray via an adhesive sheet disposed between the substrate electrode and the tray.

According to a fourth aspect of the present invention, there is provided a plasma processing method comprising:

transporting a substrate into a vacuum chamber;

holding the substrate while deforming the substrate into a convex shape toward a substrate electrode in the vacuum chamber;

bringing a neighborhood of a central portion of the substrate deformed in the convex shape into contact with an adhesive sheet provided on a surface of the substrate electrode;

bringing almost an entire surface of the substrate into contact with the adhesive sheet provided on the surface of the substrate electrode; and

processing the substrate or a film on the substrate by evacuating an interior of the vacuum chamber and supplying gas into the vacuum chamber, and then generating plasma in the vacuum chamber while controlling the interior of the vacuum chamber to be at a specified pressure.

According to a fifth aspect of the present invention, there is provided a plasma processing method comprising:

transporting a substrate into a vacuum chamber;

holding the substrate above a convex substrate electrode in the vacuum chamber;

bringing a neighborhood of a central portion of the substrate into contact with an adhesive sheet provided on a surface of the substrate electrode;

bringing almost an entire surface of the substrate into contact with the adhesive sheet provided on the surface of the substrate electrode by pressing an outer edge portion of the substrate against the substrate electrode; and

processing the substrate or a film on the substrate by evacuating an interior of the vacuum chamber and supplying gas into the vacuum chamber, and then generating plasma in the vacuum chamber while controlling the interior of the vacuum chamber to be at a specified pressure.

According to a sixth aspect of the present invention, there is provided a plasma processing method comprising:

bringing almost an entire surface of a substrate into contact with an adhesive sheet provided on a surface of a tray;

transporting the tray into a vacuum chamber;

holding the tray above a substrate electrode in the vacuum chamber;

placing the tray on the substrate electrode; and

processing the substrate or a film on the substrate by evacuating an interior of the vacuum chamber and supplying gas into the vacuum chamber, and then generating plasma in the vacuum chamber while controlling the interior of the vacuum chamber to be at a specified pressure.

According to a seventh aspect of the present invention, there is provided the plasma processing method as defined in the first aspect, wherein the adhesive sheet has a thermal conductivity of not smaller than 0.1 W/m·K.

According to an eighth aspect of the present invention, there is provided the plasma processing method as defined in the first aspect, wherein the adhesive sheet has Asker C of not greater than 80.

According to a ninth aspect of the present invention, there is provided the plasma processing method as defined in the first aspect, wherein the adhesive sheet has a hardness of 50 to 60.

According to a tenth aspect of the present invention, there is provided the plasma processing method as defined in the first aspect, wherein the adhesive sheet has a thickness of 0.05 to 0.5 mm.

According to an eleventh aspect of the present invention, there is provided the plasma processing method as defined in the first aspect, wherein the substrate is made of glass or ceramics.

According to a twelfth aspect of the present invention, there is provided the plasma processing method as defined in the first aspect, wherein the substrate is a resin sheet.

According to a thirteenth aspect of the present invention, there is provided the plasma processing method as defined in the first aspect, wherein the substrate has a thickness of 0.001 to 1 mm.

According to a fourteenth aspect of the present invention, there is provided the plasma processing method as defined in the first aspect, wherein the substrate has a thickness of 0.001 to 0.5 mm.

According to a fifteenth aspect of the present invention, there is provided the plasma processing method as defined in the first aspect, wherein, assuming that the substrate has a Young's modulus E (Pa), the substrate has a Poisson's ratio ν, the substrate has a characteristic length a (m) and the substrate has a thickness h (m), then there holds an expression: 600×(1−ν2)a4/(256×Eh3)>0.005 (m).

According to a sixteenth aspect of the present invention, there is provided a plasma processing apparatus comprising:

a vacuum chamber;

a gas supply unit for supplying gas into the vacuum chamber;

an exhausting unit for exhausting an interior of the vacuum chamber;

a pressure-regulating valve for controlling the interior of the vacuum chamber to be at a specified pressure;

a substrate electrode for placing thereon a substrate in the vacuum chamber;

a high-frequency power supply capable of supplying a high-frequency power to the substrate electrode or a plasma source; and

an adhesive sheet, which is disposed on a surface of the substrate electrode and on which the substrate is placed.

According to a seventeenth aspect of the present invention, there is provided a plasma processing apparatus comprising:

a substrate mounting station for placing a substrate on a tray having a surface provided with an adhesive sheet;

a vacuum chamber;

a gas supply unit for supplying gas into the vacuum chamber;

an exhausting unit for exhausting an interior of the vacuum chamber;

a pressure-regulating valve for controlling the interior of the vacuum chamber to be at a specified pressure;

a substrate electrode for placing thereon the tray in the vacuum chamber; and

a high-frequency power supply capable of supplying a high-frequency power to the substrate electrode or a plasma source.

According to an eighteenth aspect of the present invention, there is provided the plasma processing apparatus as defined in the sixteenth aspect, wherein the adhesive sheet has a thermal conductivity of not smaller than 0.1 W/m·K.

According to a nineteenth aspect of the present invention, there is provided the plasma processing apparatus as defined in the sixteenth aspect, wherein the adhesive sheet has Asker C of not greater than 80.

According to a twentieth aspect of the present invention, there is provided the plasma processing apparatus as defined in the sixteenth aspect, wherein the adhesive sheet has a hardness of 50 to 60.

According to a twenty-first aspect of the present invention, there is provided the plasma processing apparatus as defined in the sixteenth aspect, wherein the adhesive sheet has a thickness of 0.05 to 0.5 mm.

According to a twenty-second aspect of the present invention, there is provided a tray for plasma processing used for plasma processing for processing a substrate or a film on the substrate, comprising:

an adhesive sheet disposed on a surface on which the substrate is placed.

According to a twenty-third aspect of the present invention, there is provided the tray for plasma processing as defined in the twenty-second aspect, comprising:

another adhesive sheet disposed on a surface opposite from the surface on which the substrate is placed.

According to a twenty-fourth aspect of the present invention, there is provided the tray for plasma processing as defined in the twenty-second aspect, wherein the adhesive sheet has a thermal conductivity of not smaller than 0.1 W/m·K.

According to a twenty-fifth aspect of the present invention, there is provided the tray for plasma processing as defined in the twenty-second aspect, wherein the adhesive sheet has Asker C of not greater than 80.

According to a twenty-sixth aspect of the present invention, there is provided the tray for plasma processing as defined in the twenty-second aspect, wherein the adhesive sheet has a hardness of 50 to 60.

According to a twenty-seventh aspect of the present invention, there is provided the tray for plasma processing as defined in the twenty-second aspect, wherein the adhesive sheet has a thickness of 0.05 to 0.5 mm.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described in detail below on the basis of the drawings.

First Embodiment

A first embodiment of the present invention will be described below with reference toFIGS. 1 through 4C.

FIG. 1shows a sectional view of a plasma processing apparatus used in the first embodiment of the present invention.

Referring toFIG. 1, by evacuating a vacuum vessel1, as one example of a vacuum chamber, by a turbo-molecular pump3, as an exhauster, while introducing a specified gas from a gas supply unit2into the vacuum vessel1and by applying high-frequency power of 13.56 MHz to a coil8(one example of a plasma source) provided along a dielectric plate7opposite to a substrate electrode6, by a coil use high-frequency power supply5while maintaining an interior of the vacuum vessel1at a specified pressure by a pressure-regulating valve4, an inductive-coupling type plasma is generated in the vacuum vessel1, and a substrate9placed on the substrate electrode6can be subjected to plasma processing.

In this specification and the claims, the substrate9can be a thin soft substrate and can be, for example, an object such that a circuit(s) is formed on a resin sheet (for example, sheet of polyimide), paper, or the like.

There is also provided a substrate-electrode use high-frequency power supply10for supplying high-frequency power to the substrate electrode6, thereby making it possible to control ion energy that reaches the substrate9. The turbo-molecular pump3and an exhaust port11are disposed just under the substrate electrode6, and the pressure-regulating valve4is an up-and-down valve disposed just under the substrate electrode6and just over the turbo-molecular pump3. The substrate electrode6is fixed to the vacuum vessel1with four props12. Operations of the gas supply unit2, the coil use high-frequency power supply5, the substrate-electrode use high-frequency power supply10, the turbo-molecular pump3, and the pressure-regulating valve4are controlled by a control unit1000. It is to be noted that the control unit1000is similar in other embodiments. Therefore, it is representatively shown only inFIG. 1and is principally omitted in figures of the other embodiments.

An adhesive sheet13is provided between the substrate electrode6and the substrate9, thereby making it possible to perform processing while effecting heat exchange between the substrate9and the substrate electrode6via the adhesive sheet13.

As one example of the adhesive sheet13, a silicone rubber film is employed. The adhesive sheet13has self-adhesion (self-tack property) in its sheet material itself. The adhesive sheet13is preferably to be able to be prevented from deteriorating due to plasma during plasma processing by having a size slightly smaller than that of the substrate9or, for example, at least about 1 mm or more smaller than an outer periphery of the substrate. This adhesive sheet13has a thermal conductivity of 0.2 W/m·K, Asker C of 60, hardness of 55, and a thickness of 0.2 mm.

It is to be noted that Asker C (ASKER C) is an index of softness of resin, and the fact that Asker C is 60 means that a value measured by an Asker C hardness meter is 60. The greater this value, the harder the material, conversely to a penetration and consistency test.

Asker C means a spring type Asker C type of the standard 0101 of The Society of Rubber Industry, Japan standards (SRIS), and the following measurement method is provided by K6301 (1995)(physical testing method of vulcanized rubber) of Japanese Industrial Standards (JIS).

Spring Type Hardness Test (Type A and Type C)

In principle, a specimen having a thickness of not smaller than 12 mm is used according to type A, and specimens each having a thickness smaller than 12 mm are stacked to secure a thickness of not smaller than 12 mm as much as possible. According to type C, a specimen having a thickness of not smaller than 6 mm is used, and specimens each having a thickness smaller than 6 mm are stacked to secure a thickness of not smaller than 6 mm as much as possible.

Moreover, a surface to be measured of the specimen is polished to become smooth when the surface is not smooth. The surface to be measured is required to have a size such that a pressing surface of a tester is required to have a size that falls at least within the surface to be measured.

With regard to the tester, a spring type hardness tester of type A or type C shown as one example inFIGS. 29A and 29Bis used. This tester indicates, as hardness on a scale303, a travel distance of an indentor301(see FIG.29C), which is protruded from a hole300alocated at a center of pressing surface300by a spring pressure and is pushed back by the rubber surface of the specimen when the pressing surface300is brought into contact with the surface of the specimen. The pressing surface300is a surface perpendicular to the indentor301and has the hole300athrough which the indentor301is put at its center as shown inFIG. 29D. A diameter of hole300amust not be smaller than 10 mm. A tolerance of a reference line (seeFIGS. 30A and 30B), which shows relationships between the scale303, movement of the indentor301, and a spring force, is assumed to be ±0.0785N{±8gf} in the case of type A and ±0.196N{±20gf} in the case of type C. Moreover, no play is accepted between movement of the indentor301and movement of the indicator302. Material of the indentor301is wear-resistant and rust-resistant, and its configuration and dimensions are as shown inFIGS. 29C and 29D. The indentor301must be correctly attached to the center of the hole300aof the pressing surface300. An indentor tip must protrude from the pressing surface300by 2.540−0.05mm at 0 on the scale303. The indentor tip surface must be located on the same plane as the pressing surface300at100on the scale303. The scale303is graduated at equal intervals from 0 to 100.

Moreover, in order to effectively prevent occurrence of a gap or foams between the adhesive sheet13and the substrate9, mutually communicating through holes13hor grooves13gfor allowing foams to easily escape may be formed in the adhesive sheet13as shown inFIG. 21orFIG. 22. Moreover, regarding a manner of arranging the grooves13g, the grooves may be linearly arranged mutually parallel as shown inFIG. 23A, arranged in a grating-like form as shown inFIG. 23B, arranged radially as shown inFIG. 23C, or arranged between projecting portions13jas shown inFIG. 23D.

FIGS. 2A through 2Cshow processes for placing a polyimide resin substrate9, which has on its surface a 300-nm thick silicon oxide film patterned by a photoresist, and has a thickness h=0.4 mm=0.0004 m, on the substrate electrode6. It is to be noted that the substrate has a Young's modulus E of 3 GPa, a Poisson's ratio ν of 0.3, a circular substrate configuration, and a diameter a of 0.15 m.

First of all, the substrate9is transported from an opening-and-closing gate22of the vacuum vessel1into the vacuum vessel1by use of a transportation arm23, and thereafter, the substrate9is held by a plurality of lift pins14(one example of a support member) (FIG. 2A). At this time, the plurality of lift pins14that move up and down inside through holes6aprovided in the substrate electrode6is provided in the vicinity of an outer peripheral portion of the substrate electrode6, and therefore, the substrate9is deformed into a convex shape protruding toward the substrate electrode6. The plurality of lift pins14(for example, four pins as shown inFIG. 2Dor three pins as shown inFIG. 2E) are arranged in point symmetry with respect to a center of the substrate9. Lower ends of the plurality of lift pins14are fixed to a drive ring100, and the drive ring100is driven to move up and down by an air cylinder101or the like as one example of a drive unit under control of the control unit1000. Without being limited to providing a drive unit such as the air cylinder101to vertically drive each of the lift pins14for enabling each of the lift pins to move up and down, or a drive unit such as the air cylinder101to vertically drive a specified number of lift pins14for enabling each of the lift pins to move up and down, one by one or together, the substrate may be simply made removable from the substrate electrode6or the adhesive sheet13.

Next, the drive ring100is moved down by driving the air cylinder101under control of the control unit1000to simultaneously gradually move down the plurality of lift pins14, thereby first bringing a neighborhood of the center of the substrate9into contact with the adhesive sheet13provided on the surface of the substrate electrode6(FIG. 2B).

By further moving down the lift pins14, the peripheral portion of the substrate9is also brought into contact with the adhesive sheet13, thereby allowing almost an entire surface of the substrate9to be brought into contact with the adhesive sheet13provided on the surface of the substrate electrode6(FIG. 2C).

By using the above-mentioned transportation procedure, it is feasible to prevent occurrence of a gap, in which gas remains, between the substrate9and the adhesive sheet13.

The substrate9was placed on the substrate electrode6, and thereafter, a silicon oxide film on the substrate9was subjected to an etching process on condition that the vacuum vessel1is supplied with CF4gas at a rate of 5 sccm and Ar gas at a rate of 45 sccm, with a temperature of the substrate electrode6maintained at 30° C., and high-frequency power was applied by 500 W to the coil8and 200 W to the substrate electrode6with an internal pressure of the vacuum vessel1maintained at 3 Pa. Consequently, etching was able to be performed at an etching rate of 100 nm/min. A processing time was 200 seconds including an over-etching time. As a result, burning of the photoresist did not occur, and a satisfactory etching process was able to be performed. When a temperature of the substrate9was measured on same conditions, the temperature of the substrate9immediately before an end of the etching was 57° C. For the sake of comparison, an etching process was performed on similar conditions by the conventional system (construction having no adhesive sheet). Consequently, burning of the photoresist occurred, and etching failed. Moreover, when a temperature of the substrate9was measured on same conditions, the temperature of the substrate9immediately before an end of the etching was 195° C.

As described above, a reason why the temperature of the substrate9was significantly lowered in comparison with the prior-art example was that processing was able to be performed while effecting heat exchange between the substrate9and the substrate electrode6via the adhesive sheet13.

When detaching the substrate9from the adhesive sheet13after the processing, reversely to the aforementioned transportation procedure, there is a procedure for first moving up the drive ring100by the air cylinder101under control of the control unit1000to simultaneously gradually move up the plurality of lift pins14, thereby detaching the substrate9from the adhesive sheet13in a peeling-off manner, and thereafter transporting the substrate9to the transportation arm23to unload the substrate9from inside the vacuum vessel1.

At this time, if the substrate9is supported aslant with respect to the surface of the adhesive sheet13by use of long lift pins14and short lift pins14instead of simultaneously detaching the substrate9from the adhesive sheet13by, for example, making the plurality of lift pins14have different lengths, then the substrate9may be more smoothly detached from the surface of the adhesive sheet13by first detaching some portions along the periphery of the substrate9from the surface of the adhesive sheet13by use of the long lift pins14and thereafter detaching remaining portions, along the periphery of the substrate9, from the surface of the adhesive sheet13by means of the short lift pins14, instead of simultaneously detaching an entire peripheral portion of the substrate9from the surface of the adhesive sheet13. In order to perform the above operation, the lift pins14may be moved up separately as described hereinabove.

FIGS. 3A through 3Cshow another example of processes for placing the substrate9on the substrate electrode6. First of all, the substrate9is transported into the vacuum vessel1, and thereafter, the substrate9is held (FIG. 3A). At this time, the lift pins14, which move up and down in through holes6aprovided in a substrate electrode6A having a convex portion6bthat protrudes while being curved upward so that a center portion becomes a top, are provided in the vicinity of an outer peripheral portion of the substrate electrode6A. Therefore, the substrate9is deformed into a convex shape protruding toward the substrate electrode6A.

Next, the lift pins14are gradually moved down to bring a neighborhood of a center of the substrate9into contact with adhesive sheet13provided on a surface of the convex portion6bof the convex substrate electrode6A that has the surface of the convex portion6b, of which a central portion in a lateral direction is curved and protruded (FIG. 3B). Further, by moving down the lift pins14, almost an entire surface of the substrate9can be brought into contact with the adhesive sheet13provided on the surface of the convex portion6bof the substrate electrode6A (FIG. 3C). In this example, the convex substrate electrode6A having a curvature of, for example, 1/100 to 1/10 is employed. Therefore, when handling a substrate9that is less prone to deformation, the substrate9can reliably be brought into contact with the adhesive sheet13initiatively from the neighborhood of the center of substrate9, and a possibility of occurrence of a gap between the substrate9and the adhesive sheet13can be reduced. This gap reducing effect is little when the curvature is smaller than 1/100, while a circuit pattern formed on the substrate9tends to easily suffer damage when the curvature exceeds 1/10. Therefore, the aforementioned range is preferable.

FIGS. 4A through 4Cshow yet another example of processes for placing the substrate9on the substrate electrode6. First of all, the substrate9is transported into the vacuum vessel1, and thereafter, the substrate9is held (FIG. 4A). In this example, the substrate9is made of a material that is less prone to deformation, and therefore, a degree of deformation of the substrate9protruding toward the substrate electrode6is remarkably less than in the case ofFIGS. 2A through 2CandFIGS. 3A through 3C.

Next, the lift pins14are moved down to bring a neighborhood of a center of the substrate9into contact with adhesive sheet13provided on a surface of convex substrate electrode6(FIG. 4B).

Next, by moving down a clamp ring16by use of ring elevation rods15to press an outer peripheral portion of the substrate9against the substrate electrode6, almost an entire surface of the substrate9can be brought into contact with the adhesive sheet13provided on the surface of the substrate electrode6(FIG. 4C). In this example, convex substrate electrode6is employed. Therefore, even in handling a substrate9that is less prone to deformation, the substrate9can reliably be brought into contact with the adhesive sheet13initiatively from the neighborhood of the center of the substrate9, and a possibility of occurrence of a gap between the substrate9and the adhesive sheet13can be reduced.

A lower surface of the clamp ring16brought into contact with the substrate9may be partially provided with adhesive members16das pressing assistance members as indicated by dotted lines inFIG. 4A. With this arrangement, by generating adhesive forces between the clamp ring16and the substrate9, the substrate9is more reliably pressed against the substrate electrode6without displacement when the substrate9is pressed against the substrate electrode6by the clamp ring16, and by lifting the substrate9a little by the adhesive forces of the adhesive members16dwhen the clamp ring16is moved up, the substrate9may be easily detached from the substrate electrode6. Also, by providing the clamp ring16partially or entirely with a corrugated member that has no adhesive force and has a mere corrugation as another pressing assistance member at portions, indicated by the dotted lines inFIG. 4A, of the clamp ring16and generating a frictional force between the ring16and the substrate9when the substrate9is pressed against the substrate electrode6by the clamp ring16, the substrate9can be more reliably pressed against the substrate electrode6without displacement.

Moreover, as shown inFIGS. 24A and 24B, by disposing an adhesive sheet13with interposition of a gap90with respect to a recess portion6dformed on the surface of the substrate electrode6, and pressing the adhesive sheet13together with the substrate9by the clamp ring16, the adhesive sheet13may enter the gap90, thereby preventing formation of a gap of foams or the like between the substrate9and the substrate electrode6. Furthermore, as shown inFIG. 24C, by contracting the adhesive sheet13itself without forming the recess portion6don the surface of the substrate electrode6when the adhesive sheet13is pressed together with the substrate9by the clamp ring16, a gap of foams or the like may be prevented from occurring between the substrate9and the substrate electrode6.

Second Embodiment

A second embodiment of the present invention will be described with reference toFIGS. 5 through 17C.

FIG. 5shows a sectional view of a plasma processing apparatus used in the second embodiment of the present invention.

Referring toFIG. 5, by evacuating a vacuum vessel1by a turbo-molecular pump3, as an exhauster, while introducing a specified gas from a gas supply unit2into the vacuum vessel1and by applying high-frequency power of 13.56 MHz to a coil8, provided along a dielectric plate7opposite to a substrate electrode6, by a coil use high-frequency power supply5while maintaining an interior of the vacuum vessel1at a specified pressure by a pressure-regulating valve4, inductive-coupling type plasma is generated in the vacuum vessel1, and a substrate9placed on the substrate electrode6can be subjected to plasma processing.

Moreover, a substrate electrode use high-frequency power supply10for supplying high-frequency power to the substrate electrode6is provided, thereby allowing ion energy that reaches the substrate9to be controlled. The turbo-molecular pump3and exhaust port11are disposed just under the substrate electrode6, and the pressure-regulating valve4is an up-and-down valve disposed just under the substrate electrode6and just over the turbo-molecular pump3. The substrate electrode6is fixed to the vacuum vessel1with four props12.

The substrate9is placed on a tray17, and an adhesive sheet13is provided between the tray17and the substrate9, thereby making it possible to perform processing while effecting heat exchange between the substrate9and the tray17via the adhesive sheet13. A silicone rubber film is used as the adhesive sheet13. This adhesive sheet13has a thermal conductivity of 0.2 W/m·K, Asker C of 60, hardness of 55, and a thickness of 0.2 mm.

The tray17is preferably made of a material, which has a thickness of 2 to 5 mm, is hydrochloric acid resistant and exhibits good thermal conductivity, and on a surface of which an oxide film is formed. The tray is preferably made of aluminum whose surface is processed with alumite as an oxide film.

A recess portion17a, for accommodating the adhesive sheet13, provided in the tray17may have roughly the same size as that of the adhesive sheet13or is greater than the adhesive sheet13as described hereinabove as shown inFIGS. 24A and 24B, so that the adhesive sheet13can protrude radially outwardly when the substrate9is pressed by clamp ring16.

The substrate9and the tray17were placed on the substrate electrode6, and thereafter, a silicon oxide film on the substrate9was subjected to an etching process on condition that the vacuum vessel1is supplied with CF4gas at a rate of 5 sccm and Ar gas at a rate of 45 sccm, with a temperature of the substrate electrode6maintained at 30° C., and high-frequency power was applied by 500 W to the coil8and 200 W to the substrate electrode6with an internal pressure of the vacuum vessel1maintained at 3 Pa. Consequently, etching was able to be performed at an etching rate of 100 nm/min.

A processing time was 200 seconds including an over-etching time. As a result, burning of a photoresist did not occur, and a satisfactory etching process was able to be performed. When a temperature of the substrate9was measured on the same conditions, the temperature of the substrate9immediately before an end of the etching was 92° C. For sake of comparison, an etching process was performed on similar conditions by the conventional system (construction having no adhesive sheet). Consequently, burning of the photoresist occurred, and etching failed. Moreover, when a temperature of the substrate9was measured on the same conditions, the temperature of the substrate9immediately before an end of the etching was 200° C.

As described above, a reason why the temperature of the substrate9was significantly lowered in comparison with the prior-art example is that processing is able to be performed while effecting heat exchange between the substrate9and the tray17via the adhesive sheet13. That is, it can be considered that a temperature rise due to plasma exposure is reduced since a thermal capacity of the tray17is much larger (ten times or more) than the thermal capacity of only the substrate9. When the tray17is used, the temperature of the substrate9is disadvantageously made higher than that of the construction of the first embodiment of the present invention using no tray17. However, by using the tray17, a possibility of occurrence of a positional shift when the substrate9is transported in a vacuum is remarkably reduced. That is, this substrate positional shift might be easily caused with respect to a transportation arm during transportation of only thin light substrate9. However, by using the tray17that has considerable weight and thickness, the substrate positional shift is less likely to occur with respect to the transportation arm during transportation, and this produces an effect of facilitating transportation in a vacuum.

As shown inFIG. 6, by providing an adhesive sheet18between the substrate electrode6and the tray17and performing processing while effecting heat exchange between the substrate electrode6and the tray17via the adhesive sheet18, a temperature rise of the substrate9can further be suppressed. Regarding such a construction,FIGS. 7A and 7Bshow processes for placing on the substrate electrode6the tray17on which the substrate9is placed. First of all, the tray17on which the substrate9is placed is transported into the vacuum vessel1, and thereafter, the tray17is held (FIG. 7A).

Next, lift pins14are gradually moved down to bring almost an entire surface of the tray17into contact with the adhesive sheet18provided on a surface of the substrate electrode6(FIG. 7B). If flatness and parallelism of the tray17and the substrate electrode6are sufficient, then it is feasible to prevent occurrence of a gap between the tray17and the adhesive sheet18.

FIGS. 8A through 8Cshow another example of processes for placing the tray17on the substrate electrode6. First of all, the tray17on which the substrate9is placed is transported into the vacuum vessel1, and thereafter, the tray17is held (FIG. 8A).

Next, the lift pins14are moved down to bring the tray17into contact with the adhesive sheet18provided on the surface of the substrate electrode6(FIG. 8B).

Next, by moving down clamp ring16by use of ring elevation rods15and pressing an outer peripheral portion of the tray17against the substrate electrode6, almost an entire surface of the tray17can be brought into contact with the adhesive sheet18provided on the surface of the substrate electrode6(FIG. 8C). In this example, it is feasible to more reliably prevent an occurrence of a gap between the tray17and the adhesive sheet18.

It is also acceptable to press an outer peripheral portion of the substrate9against the substrate electrode6instead of pressing the outer peripheral portion of the tray17against the substrate electrode6. When the substrate9is susceptible to a force perpendicular to its surface, it is preferable to press the outer peripheral portion of the tray17against the substrate electrode6in terms of less damage inflicted on the substrate9.

The substrate9is transported and placed on the adhesive sheet13in the aforementioned embodiments. However, as shown inFIGS. 25A through 25C, it is acceptable to transport the substrate9and the adhesive sheet13as an integrated body, place the same on a plurality of lift pins14, place this resulting body on substrate electrode6and adhesively fix the same in a state in which the adhesive sheet13is preparatorily detachably stuck tightly to a lower surface of the substrate9and no foams exist. When the substrate9is moved up and down, the plurality of lift pins14directly support the substrate9penetrating the adhesive sheet13, and the substrate9is allowed to be stably moved up and down. As described above, if the substrate9is transported with the adhesive sheet13preparatorily stuck to the lower surface of the substrate9, it is feasible to effectively prevent occurrence of a gap as a consequence of intrusion of foams between the lower surface of the substrate9and the adhesive sheet13when the substrate9is placed on the substrate electrode6.

Moreover, as shown inFIG. 26, the adhesive sheet13is not limited to one constructed only of one layer, but is allowed to be constructed of two layers. That is, as shown inFIG. 26, the adhesive sheet13may be constructed of two layers of an upper adhesive sheet13aand a lower adhesive sheet13b. In this case, when (hardness of upper adhesive sheet13a>hardness of lower adhesive sheet13b), the upper adhesive sheet13ahas lower adhesion and abundant detachability. Therefore, this construction is appropriate for an adhesive sheet attached to the upper surface of the electrode or the tray. Conversely, when (hardness of upper adhesive sheet13a<hardness of lower adhesive sheet13b), the lower adhesive sheet13bhas lower adhesion and abundant detachability. Therefore, this construction is appropriate for an adhesive sheet attached to the lower surface of the tray or the substrate9.

FIG. 9is a plan view showing an overall construction of a plasma processing apparatus used in the second embodiment of the present invention. The apparatus is constructed of three units of a reaction chamber19(including the vacuum vessel1) for performing plasma processing, a load lock chamber20, and an atmospheric transporting section21, and these units are partitioned by gate valves22that are opening-and-closing gates. The load lock chamber20is internally provided with transportation arm23and is able to perform reception and delivery of the tray17between the atmospheric transporting section21and the load lock chamber20, and reception and delivery of the tray17between the reaction chamber19and the load lock chamber20. An atmospheric arm24is to receive and deliver the substrate9or the tray17between the arm and a substrate cassette25or a tray cassette26.

The atmospheric arm24performs the reception and delivery of the substrate9or the tray17between the arm24and substrate placement station27for placing the substrate9on the tray17, on the surface of which the adhesive sheet13is provided. The substrate cassette25and the tray cassette26are provided on a cassette elevation table28. When the atmospheric arm24receives and delivers the substrate cassette25or the tray cassette26and the substrate9or the tray17, the atmospheric arm24performs a back-and-forth motion as shown inFIG. 10, while the cassette elevation table28moves up and down in accordance with appropriate timing.

FIGS. 11A through 11Eshow a procedure for sticking the adhesive sheet13to the tray17. First of all, the tray17and the adhesive sheet13, whose both surfaces are covered with protection films29and30, are prepared (FIG. 11A).

Next, part of the protection film30is peeled off and brought into contact with a bottom surface of an adhesive sheet-disposing recess portion17aof the tray17, and a roller31is subsequently rotated on the protection film29while tensioning one end of the protection film30, thus sticking the adhesive sheet13inside the adhesive sheet-disposing recess portion17aof the tray17(FIGS. 11B and 11C).

The tray17, which is provided with the adhesive sheet13on its surface on which the substrate9is to be placed, can be obtained according to the aforementioned procedure (FIG. 11E).

In order to improve adhesion between the substrate9and the tray17in the process for placing the substrate9on the tray17, it is sometimes preferable that used is a tray17A having a convex shape having a surface of a convex portion17bwhose central portion in a lateral direction is curved and protruded.FIGS. 12A through 12Eshow a procedure for sticking adhesive sheet13to the tray17A in this case. First of all, convex tray17A and the adhesive sheet13, whose both surfaces are covered with protection films29and30, are prepared (FIG. 12A).

Next, part of the protection film30is peeled off and brought into contact with the tray17A, and a roller31is subsequently rotated on the protection film29while tensioning one end of the protection film30, thus sticking the adhesive sheet13to the tray17A (FIGS. 12B and 12C).

Next, the protection film29is peeled off (FIG. 12D). The convex tray17A, which is provided with the adhesive sheet13on its surface on which the substrate9is to be placed, can be obtained according to the aforementioned procedure (FIG. 12E).

As shown inFIG. 27, it is acceptable to place the substrate9on the adhesive sheet13of the tray17A and rotate the roller131on the substrate9for removal of a gap between the substrate9and the adhesive sheet13.

FIG. 13andFIGS. 14A through 14Cshow another example of processes for placing the substrate9on the tray17.

FIG. 13is a perspective view of the tray17, in which through holes32for receiving lift pins33are provided at, for example, a bottom surface of adhesive sheet-disposing recess portion17a. First of all, the tray17and the substrate9are transported onto the substrate placement station27(seeFIG. 9), and thereafter, the substrate9is held above the tray17(FIG. 14A). At this time, the lift pins33that move up and down inside the through holes32provided in the tray17are disposed in the vicinity of an outer peripheral portion of the tray17. Therefore, the substrate9is deformed in a convex shape protruding toward the tray17. Next, the lift pins33are gradually moved down, and a neighborhood of a center of the substrate9is brought into contact with adhesive sheet13provided on a surface of the tray17(FIG. 14B).

By further moving down the lift pins33, almost an entire surface of the substrate9can be brought into contact with the adhesive sheet13provided on the surface of the tray17(FIG. 14C).

By using the aforementioned procedure, it is feasible to prevent occurrence of a gap between the substrate9and the adhesive sheet13(in other words, no foams enter).

FIGS. 15A through 15Cshow another example of processes for placing substrate9on tray17A. First of all, the tray17A and the substrate9are transported onto the substrate placement station27(seeFIG. 9), and thereafter, the substrate9is held above the tray17A (FIG. 15A). At this time, lift pins33, which move up and down in through holes32provided in the tray17A, are disposed in the vicinity of an outer peripheral portion of the tray17A. Therefore, the substrate9is deformed in a convex shape protruding toward the tray17A.

Next, the lift pins33are gradually moved down, and a neighborhood of a center of the substrate9is brought into contact with adhesive sheet13provided on a surface of the tray17A (FIG. 15B).

By further moving down the lift pins33, almost an entire surface of the substrate9can be brought into contact with the adhesive sheet13provided on the surface of the tray17A (FIG. 15C). In this example, since convex tray17A is employed, even in handling a substrate9that is less prone to deformation, the substrate can reliably be brought into contact with the adhesive sheet13initiatively from the neighborhood of the center of the substrate9, and a possibility of an occurrence of a gap between the substrate9and the adhesive sheet13can be reduced.

FIGS. 16A through 16Cshow yet another example of processes for placing substrate9on tray17A. The tray17A and the substrate9are transported onto the substrate placement station27(seeFIG. 9), and thereafter, the substrate9is held above the tray17A (FIG. 16A). In this example, the substrate9is made of a material that is less prone to deformation, and therefore, a degree of deformation of the substrate9protruding toward the tray17A is remarkably less than in the case ofFIGS. 14A through 14CandFIGS. 15A through 15C.

Next, lift pins33are moved down, and a neighborhood of a center of the substrate9is brought into contact with adhesive sheet13provided on a surface of the convex tray17A (FIG. 16B).

Next, by moving down a frame-shaped or rod-shaped clamping jig35capable of contacting an outer peripheral portion of the substrate9with use of a plurality of jig elevation bars34, and then pressing the outer peripheral portion of the substrate9against the tray17A, almost an entire surface of the substrate9can be brought into contact with the adhesive sheet13provided on the surface of the tray17A (FIG. 16C).

In this example, since convex tray17A is employed, even in handling a substrate9that is less prone to deformation, the substrate9can reliably be brought into contact with the adhesive sheet13initiatively from the neighborhood of the center of substrate9, and a possibility of occurrence of a gap between the substrate9and the adhesive sheet13can be reduced. When transporting the tray17A into the vacuum vessel1, it is preferable to transport the tray17A with the outer peripheral portion of the substrate9kept pressed against the tray17A by the clamping jig35.

FIGS. 17A through 17Cshow yet another example of processes for placing substrate9on tray17. First of all, the tray17and the substrate9are transported onto the substrate placement station27(seeFIG. 9), and thereafter, the substrate9is held above the tray17(FIG. 17A). In this example, exhaust holes36are provided in the tray17. Then, lift pins33are moved down while exhausting gas between the substrate9and the tray17by an exhausting unit150, and a neighborhood of a center of the substrate9is brought into contact with adhesive sheet13provided on a surface of the tray17(FIG. 17B).

By further moving down the lift pins33, almost an entire surface of the substrate9can be brought into contact with the adhesive sheet13provided on the surface of the tray17(FIG. 17C). In this example, contact processes are performed while exhausting gas between the substrate9and the tray17, and therefore, a possibility of occurrence of a gap between the substrate9and the adhesive sheet13is low, and there is an advantage in that foams are less likely to occur between the substrate9and the adhesive sheet13.

It is noted that the substrate placement station27(seeFIG. 9) may also be provided within a second vacuum vessel. In this case also, there is an advantage in that foams are less likely to intervene between the substrate9and the adhesive sheet13.

It is also possible that exhaust holes36are provided only in a central portion of the tray17, as shown inFIG. 28, so that the substrate9is sucked at only its central portion to the adhesive sheet13so as to be affixable thereto sequentially from the central portion to the peripheral portion of the substrate9, thus making it implementable to eliminate gaps or foams more effectively.

The foregoing embodiments of the present invention have been described only by way of example to illustrate some of many variations as to the configuration of the vacuum vessel (chamber), the system and arrangement of the plasma source, and the like within the application range of the present invention. It is needless to say that many other variations besides those illustrated above are conceivable for application of the present invention.

Although the foregoing embodiments have been described exemplarily for a case where the present invention is applied to dry etching, the present invention is of course applicable to CVD, sputtering, or other plasma processing.

Further, the foregoing embodiments have been described exemplarily for a case where the internal pressure of the vacuum vessel is 3 Pa. However, since it is over a pressure range generally from 0 to 500 Pa or lower that heat exchange between a substrate and a substrate electrode, between a substrate and a tray, or between a tray and a substrate electrode matters in the prior art example, the present invention is particularly effective for such temperatures within this pressure range.

Further, although the foregoing embodiments have been described exemplarily for a case where a film on the substrate placed on the tray is processed, the present invention is applicable also to cases where the substrate itself is processed.

Further, although the foregoing embodiments have been described exemplarily for a case where an adhesive sheet is provided on one side of the tray, it is also possible that adhesive sheets are provided on both sides of the tray as shown inFIG. 18. In this case, there is no need for providing any adhesive sheet on the surface of the substrate electrode, thus making it easier to replace the adhesive sheets, advantageously.

Further, the foregoing embodiments have been described exemplarily for a case where thermal conductivity of the adhesive sheet is 0.2 W/m·K. However, for enhancement of heat exchange between a substrate and a substrate electrode, between a substrate and a tray or between a tray and a substrate electrode, the thermal conductivity of the adhesive sheet is preferably not less than 0.1 W/m·K.

Further, the foregoing embodiments have been described exemplarily for a case where the ASKER C of the adhesive sheet is 60. However, for enhancement of heat exchange between a substrate and a substrate electrode, between a substrate and a tray, or between a tray and a substrate electrode, the ASKER C of the adhesive sheet is preferably not more than 80. With the ASKER C larger than 80, adhesiveness would become poorer, thereby causing heat exchangeability to lower.

Further, the foregoing embodiments have been described exemplarily for a case where hardness of the adhesive sheet is 55. However, for enhancement of heat exchange between a substrate and a substrate electrode, between a substrate and a tray, or between a tray and a substrate electrode, the hardness of the adhesive sheet is preferably 50 to 60. With the hardness of the adhesive sheet being lower than 50, the adhesive sheet would be too soft, thereby allowing foams to easily enter into an adhesion surface. Conversely, with the hardness of the adhesive sheet being higher than 60, the adhesive sheet would be too hard, resulting in poorer adhesiveness.

Further, the foregoing embodiments have been described exemplarily for a case where thickness of the adhesive sheet is 0.2 mm. However, for enhancement of heat exchange between a substrate and a substrate electrode, between a substrate and a tray, or between a tray and a substrate electrode, the thickness of the adhesive sheet is preferably 0.05 to 0.5 mm. With the thickness of the adhesive sheet being smaller than 0.05 mm, the adhesive sheet would be less easy to handle, thereby making it difficult to perform the step of affixing the adhesive sheet to the substrate electrode or the tray, while the adhesive sheet itself would be insufficient in terms of a cushioning property, thereby making it difficult to obtain flatness, with a result of deteriorated cooling efficiency. Conversely, with the thickness of the adhesive sheet being larger than 0.5 mm, a thermal resistance would be become larger, thereby causing heat exchangeability to lower.

Further, although the foregoing embodiments have been described exemplarily for a case where the substrate is made of polyimide resin, the present invention is applicable to cases where various substrates are used. With an electrically conductive substrate being used, there is a possibility that a temperature of the substrate can be controlled to some extent by electrostatic suction. Therefore, the present invention is effective particularly when the substrate is a dielectric. Examples of such cases may include cases where the substrate is made of glass, ceramics, a resin sheet, or the like.

Further, the foregoing embodiments have been described exemplarily for a case where a thickness of the substrate is 0.4 mm. However, the present invention is particularly effective when the thickness of the substrate is 0.001 to 1 mm, and further particularly effective when the thickness of the substrate is 0.001 to 0.5 mm. With the thickness of the substrate being less than 0.001 mm, substrate conveyance becomes difficult to perform. Conversely, with the thickness of the substrate being more than 1 mm, the substrate is large in terms of thermal capacity, so that temperature change of the substrate under processing becomes relatively small. With high-frequency power being small (e.g., about 100 W), even if the thickness of the substrate is 0.5 mm to 1 mm, the substrate is large in terms of thermal capacity, so that a temperature change of the substrate under processing becomes relatively small. Otherwise, with use of a large-scale, thin and solid, crack-prone substrate (silicon, glass, ceramics and the like), especially when the substrate has a thickness of not more than 1 mm and an area of not less than 0.1 m2, it is difficult to use gas as a heating medium as described in the prior art, and therefore the present invention is particularly effective.

Further, the foregoing embodiments have been described exemplarily for a case where the substrate has a thickness h of 0.0004 m, a Young's modulus E of 3 GPa, a Poisson's ratio ν of 0.3, and a circular shape having a diameter a of 0.15 m. However, the present invention is a plasma processing method which is effective particularly when 600×(1−ν2)a4/(256×Eh3)>0.005 (m), where E (Pa) is substrate's Young's modulus, ν is substrate's Poisson's ratio, a (m) is substrate's characteristic length, and h (m) is substrate's thickness. That is, the present invention produces particularly large effects when such substrates as those satisfying the above relational expression are processed.

Generally, given that a disc has a Young's modulus of E (Pa), a Poisson's ratio of ν, a diameter of a (m), and a thickness of h (m), a uniformly distributed load of p (Pa), when applied to the disc with the disc fixed at its periphery, results in a flexure amount of 3×(1−ν2)pa4/(256−Eh3) (m) at a center of the disc. As is known, generally, gas pressure of at least 200 Pa is necessary in order to fulfill temperature control of the substrate by feeding gas serving as a heating medium to between the substrate and the substrate electrode with the substrate fixed at its periphery by a clamp ring.

Accordingly, a substrate satisfying the expression that 600×(1−ν2)a4/(256×Eh3)>0.005 means a substrate which has its periphery fixed and which would result in a flexure of at least 0.005 m (=5 mm) with application of a 200 Pa gas pressure. Occurrence of such large deformation might not only impair uniformity of processing but also cause occurrence of abnormal discharge in a space formed between the substrate and the substrate electrode, and additionally might cause a device formed on the substrate to be broken by stress.

The above description has been made for a circular-shaped substrate. Otherwise, also for rectangular or other shapes, a range over which the present invention produces great application effects can be defined, in terms of their characteristic length a (e.g., diagonal line of a rectangular shape), approximately by the expression that 600×(1−ν2)a4/(256×Eh3)>0.005. Conversely, in a case of substrates which do not satisfy the above expression, those substrates are less liable to deformation even with use of gas as a heating medium and therefore, in some cases, may be processed by conventional methods without a need for applying the present invention.

Another modification example of an above embodiment of the present invention is shown inFIGS. 31–33. InFIGS. 31–33, a plurality of resin tapes130are arranged on a surface of substrate electrode6via specified gaps, and then an adhesive sheet13C is arranged on the plurality of resin tapes130and the surface of the substrate electrode6to fix the adhesive sheet13C onto the plurality of resin tapes130and the surface of the substrate electrode6with an adhesive force of the adhesive sheet13C. In this state, approximately strip-shaped spaces132are formed between each resin tape130and the adhesive sheet13C on both sides of each resin tape130, whereas onto an upper surface of the adhesive sheet13C, an uneven shape defined by the plurality of resin tapes130is transferred via the adhesive sheet13C itself, while a difference level of the uneven shape defined by the plurality of resin tapes130is reduced slightly, resulting in obtaining an uneven upper surface of the adhesive sheet13C.

As shown inFIG. 33, both ends of each resin tape130are projected outside of an area where the adhesive sheet13C is located, and thus, both ends of the approximately strip-shaped spaces132defined between each resin tape130and the adhesive sheet13C are opened at a periphery of the adhesive sheet13C, without being closed by the adhesive sheet13C. As a result, in sticking the adhesive sheet13C to the substrate electrode6, air in the approximately strip-shaped spaces132on a substrate electrode side is discharged through the approximately strip-shaped spaces132when an interior of a vacuum vessel is evacuated, resulting in prevention of any deformation of the adhesive sheet13C due to expansion of foams.

When a substrate9is placed on the uneven upper surface of the adhesive sheet13C to fix the substrate9to the adhesive sheet13C with adhesive force of the adhesive sheet13C, approximately strip-shaped spaces131are defined by the uneven upper surface of the adhesive sheet13C and a lower surface of the substrate9while both ends of the spaces131are opened in their longitudinal directions. Therefore, when the substrate9is placed on the adhesive sheet13C, air in the approximately strip-shaped spaces131is discharged through the approximately strip-shaped spaces131when the interior of the vacuum vessel is evacuated, resulting in prevention of any deformation of the adhesive sheet13C due to expansion of foams.

In order to form such an uneven upper surface of the adhesive sheet13C, instead of provision of the plural resin tapes130described above, grooves may be formed in the surface of the substrate electrode6itself. The above means for preventing expansion of foams can be applied to portions between a tray and a substrate, or portions between the substrate electrode and a tray.

As apparent from the foregoing description, according to the plasma processing method of the first aspect of the present invention, there is provided a plasma processing method which comprises: evacuating an interior of a vacuum chamber and supplying gas into the vacuum chamber, and then generating plasma in the vacuum chamber while controlling the interior of the vacuum chamber to be at a specified pressure; and processing a substrate or a film on a substrate placed on a substrate electrode in the vacuum chamber while performing heat exchange between the substrate and the substrate electrode via an adhesive sheet disposed between the substrate electrode and the substrate. Therefore, temperature controllability of the substrate can be improved.

Also, according to the plasma processing method of the second aspect of the present invention, there is provided a plasma processing method which comprises: evacuating an interior of a vacuum chamber and supplying gas into the vacuum chamber, and then generating plasma in the vacuum chamber while controlling the interior of the vacuum chamber to be at a specified pressure; and processing a substrate or a film on a substrate on a tray placed on a substrate electrode in the vacuum chamber while performing heat exchange between the tray and the substrate electrode via an adhesive sheet disposed between the tray and the substrate. Therefore, temperature controllability of the substrate can be improved.

Also, according to the plasma processing method of the fourth aspect of the present invention, there is provided a plasma processing method which comprises: transporting a substrate into a vacuum chamber; holding the substrate while deforming the substrate into a convex shape toward a substrate electrode in the vacuum chamber; bringing a neighborhood of a central portion of the substrate deformed in the convex shape into contact with an adhesive sheet provided on a surface of the substrate electrode; bringing almost an entire surface of the substrate into contact with the adhesive sheet provided on the surface of the substrate electrode; and processing the substrate or a film on the substrate by evacuating an interior of the vacuum chamber and supplying gas into the vacuum chamber, and then generating plasma in the vacuum chamber while controlling the interior of the vacuum chamber to be at a specified pressure. Therefore, temperature controllability of the substrate can be improved.

Also, according to the plasma processing method of the fifth aspect of the present invention, there is provided a plasma processing method which comprises: transporting a substrate into a vacuum chamber; holding the substrate above a convex substrate electrode in the vacuum chamber; bringing a neighborhood of a central portion of the substrate into contact with an adhesive sheet provided on a surface of the substrate electrode; bringing almost an entire surface of the substrate into contact with the adhesive sheet provided on the surface of the substrate electrode by pressing an outer edge portion of the substrate against the substrate electrode; and processing the substrate or a film on the substrate by evacuating an interior of the vacuum chamber and supplying gas into the vacuum chamber, and then generating plasma in the vacuum chamber while controlling the interior of the vacuum chamber to be at a specified pressure. Therefore, temperature controllability of the substrate can be improved.

Also, according to the plasma processing method of the sixth aspect of the present invention, there is provided a plasma processing method which comprises: bringing almost an entire surface of a substrate into contact with an adhesive sheet provided on a surface of a tray; transporting the tray into a vacuum chamber; holding the tray above a substrate electrode in the vacuum chamber; placing the tray on the substrate electrode; and processing the substrate or a film on the substrate by evacuating an interior of the vacuum chamber and supplying gas into the vacuum chamber, and then generating plasma in the vacuum chamber while controlling the interior of the vacuum chamber to be at a specified pressure. Therefore, temperature controllability of the substrate can be improved.

Also, according to the plasma processing apparatus of the sixteenth aspect of the present invention, there is provided a plasma processing apparatus which comprises: a vacuum chamber; a gas supply unit for supplying gas into the vacuum chamber; an exhausting unit for exhausting an interior of the vacuum chamber; a pressure-regulating valve for controlling the interior of the vacuum chamber to be at a specified pressure; a substrate electrode for placing thereon a substrate in the vacuum chamber; a high-frequency power supply capable of supplying a high-frequency power to the substrate electrode or a plasma source; and an adhesive sheet, which is disposed on a surface of the substrate electrode and on which the substrate is placed. Therefore, temperature controllability of the substrate can be improved.

Also, according to the plasma processing apparatus of the seventeenth aspect of the present invention, there is provided a plasma processing apparatus which comprises: a substrate mounting station for placing a substrate on a tray having a surface provided with an adhesive sheet; a vacuum chamber; a gas supply unit for supplying gas into the vacuum chamber; an exhausting unit for exhausting an interior of the vacuum chamber; a pressure-regulating valve for controlling the interior of the vacuum chamber to be at a specified pressure; a substrate electrode for placing thereon the tray in the vacuum chamber; and a high-frequency power supply capable of supplying a high-frequency power to the substrate electrode or a plasma source. Therefore, temperature controllability of the substrate can be improved.

Also, according to the tray for plasma processing of the twenty-second aspect of the present invention, there is provided a tray for plasma processing which comprises: an adhesive sheet disposed on a surface on which a substrate is placed. Therefore, temperature controllability of the substrate can be improved.

In addition, combining any arbitrary embodiments together appropriately from among the foregoing various embodiments allows their respective effects to be produced.