The present invention relates to a plasma processing apparatus and a plasma processing method.
As for solar batteries, the optical confinement technique has been developed in order to improve conversion efficiency. According to the optical confinement techniques, a solar battery surface is roughened, a texture is formed on the solar battery surface, or a concavo-convex shape is formed on a substrate itself. As for the roughening, roughening by wet etching is disclosed in patent document 1, and roughening by dry etching (RIE etching) is disclosed in patent document 2, and it is known that isotropic plasma is used in the process. In addition, as for the formation of the texture, formation of a texture by wet etching is disclosed in each of patent documents 3 and 4, and formation of a texture by dry etching (RIE etching) is disclosed in patent document 5. In addition, as for the formation of the concavo-convex shape in the substrate itself, formation of a V groove in a substrate surface by wet etching is disclosed in patent document 6, and formation of a V groove by mechanical etching is disclosed in patent document 7.
Meanwhile, there is a commonly-known dry etching apparatus which performs a batch process by use of a tray capable of conveying a plurality of substrates. For example, patent document 8 discloses a plasma processing apparatus in which substrates are housed and conveyed in a plurality of substrate housing holes each having a bottom and provided in a tray. In addition, patent document 9 discloses a plasma processing apparatus in which substrates are housed and conveyed in substrate housing holes each penetrating in a thickness direction and provided in a tray.
Patent Document 1: Japanese Patent No. 3301663
Patent Document 2: JP 2003-197940 A
Patent Document 3: Japanese Patent No. 2997366
Patent Document 4: Japanese Patent No. 2866982
Patent Document 5: JP 2010-21196 A
Patent Document 6: Japanese Patent No. 2989055
Patent Document 7: Japanese Patent No. 2749228
Patent Document 8: JP 2006-066417 A
Patent Document 9: Japanese Patent No. 436105
Whenever any one of the above-described optical confinement techniques is employed, it is necessary to process front and back surfaces of the solar battery and the substrate to form various shapes. In such process, high production efficiency is required, and also high shape controllability is required to efficiently implement the optical confinement.
The wet etching is generally performed by the batch process, and the isotropic plasma process is also generally performed by the batch process using a barrel type plasma processing apparatus. In those butch processes, it is difficult to implement the high shape controllability. Meanwhile, when the wet etching and the isotropic plasma process are executed by a single-wafer process, in order to ensure the shape controllability, production efficiency is considerably low, so that production cost is considerably increased.
Anisotropic etching by the RIE etching can provide the high shape controllability, but when it is executed by the single-wafer process, its production efficiency is considerably low.
As for the plasma device disclosed in the patent document 8 having the configuration in which the substrates are housed in the plurality of the holes each having the bottom and provided in the conveyable tray, the batch process can be performed as described above. However, each substrate housed in the hole having the bottom is cooled with the tray interposed, so that the substrate cannot be effectively cooled. As a result, high bias power cannot be inputted, and temperature controllability is not favorable, so that the productivity and the shape controllability are both not favorable. As for the plasma processing apparatus in the patent document 9 having the configuration in which the substrates are housed in the holes penetrating in the thickness direction and provided in the conveyable tray, the batch process can be performed. Since each substrate can be directly cooled without the tray, the substrate can be effectively cooled and high bias power can be inputted.
The substrate of the solar battery is rectangular or angular in shape in general. However, in the plasma processing apparatus disclosed in the patent document 9, the batch process is intended to be performed mainly for a plurality of round-shaped substrates, so that enough consideration is not made to prevent an increase in size of the tray and therefore an increase in size of the device when the angular substrate is used. Especially, the substrate of the current solar battery is 125 mm square in general, but in a case where the nine angular substrates each having this size are arranged by 3×3 in the tray in the patent document 9, respective circumstances of the nine angular substrates need to be surrounded by the tray, so that the tray is increased in size. As the tray is increased in size, the plasma processing apparatus is increased in size as a whole.
As described above, regarding the conventional plasma process, it is not possible to optimize both shape controllability and productivity while the device is prevented from being increased in size, with respect to the relatively large angular substrate like the substrate of the solar battery.
It is an object of the present invention to provide a plasma processing apparatus and a plasma processing method capable of realizing both high shape controllability and favorable productivity while the device is prevented from being increased in size.
A first aspect of the present invention provides a plasma processing apparatus comprising, a conveyable tray comprising at least one substrate housing hole provided so as to penetrate in a thickness direction to house a plurality of substrates, and a substrate support section protruding from a hole wall of the substrate housing hole to support an outer edge section of a lower surface of each of the plurality of the substrates housed in the substrate housing hole, a plasma generation source for generating plasma in a chamber in which the tray is to be conveyed, and a stage arranged in the chamber and comprising a tray support section for supporting the tray, and a substrate installation section to be inserted from a lower surface side of the tray to the substrate housing hole, to install lower surfaces of the plurality of the substrates transferred from the substrate support section on a substrate installation surface which is an upper end surface of the substrate installation section.
The lower surface of the substrate is directly installed on the substrate installation surface of the substrate installation section without having the tray between them. More specifically, the substrate installation section is inserted from the lower surface side of the tray into the substrate housing hole, and the substrate is installed on the substrate installation surface which is an upper end surface of the substrate installation section. The substrate directly installed on the substrate installation surface without having the tray between them can be cooled with high efficiency, and its temperature can be controlled with high precision. As a result, the high shape controllability can be realized.
In addition, since the plurality of the substrates are housed in at least one substrate housing hole in the tray, the batch process can be performed for the plurality of the substrates, so that the favorable productivity can be realized.
Furthermore, not one but the plurality of the substrates are housed in each substrate housing hole in the tray, and the plurality of the substrates transferred from the substrate support section of the substrate housing hole are installed on the substrate installation surface of the substrate installation section in the stage. Since the plurality of the substrates are housed in the substrate housing hole in the tray, the tray can be prevented from being increased in size, and therefore the plasma processing apparatus can be prevented from being increased in size. In addition, since the plurality of the substrates are arranged on the substrate installation surface of the one substrate installation section, the structure of the stage can be simplified.
As described above, according to the plasma processing apparatus in the present invention, the high shape controllability and the favorable productivity can be both realized while the device is prevented from being increased in size.
Specifically, the tray houses the plurality of the substrates so that abutment sections of the adjacent substrates abut on each other.
For example, the substrate is an angular substrate, and the abutment section is one side of the angular substrate.
Preferably, the plasma processing apparatus further includes a deflection prevention member provided in the tray so as to cross the substrate housing hole in planar view to support a lower surface side of the substrate, and a housing groove provided in the substrate support section of the stage to receive the deflection prevention member when the tray is supported by the tray support section.
Since the deflection prevention member is provided in addition to the substrate support section, the housed substrate is prevented from being deflected downward due to its own weight even when the plurality of the relatively large substrates are housed in each substrate housing hole. On the other hand, the deflection prevention member does not prevent the substrate from being installed on the substrate installation surface because it is housed in the housing groove of the substrate installation section in the stage.
Preferably, the plasma processing apparatus further includes an electrostatic chucking electrode for electrostatically chucking the substrate onto the substrate installation surface, and a drive power supply for supplying a drive voltage to the electrostatic chucking electrode.
Moreover, preferably, the plasma processing apparatus further includes a cooling mechanism for cooling the stage.
More preferably, the plasma processing apparatus further includes a heat-transfer gas supply mechanism for supplying a heat-transfer gas between the substrate installation surface and the substrate.
When a DC voltage is applied from the drive power supply to the electrostatic chucking electrode, the substrate is held on the substrate installation surface with a high degree of adhesion. As a result, heat conduction by the heat-transfer gas is favorably provided between the substrate installation surface serving as one section of the stage which is cooled by the cooling mechanism, and the substrate, so that the substrate can be cooled down with high cooling efficiency, and the substrate temperature can be controlled with high precision.
A second aspect of the present invention provides a plasma processing method including providing a tray having at least one substrate housing hole provided so as to penetrate in a thickness direction to house a plurality of substrates, and a substrate support section protruding from a hole wall of the substrate housing hole, housing the plurality of the substrates in the substrate housing hole in the tray so that an outer edge section of a lower surface of each of the substrates is put on the substrate support section, lowering the tray toward a stage in a chamber so that the tray is supported with a tray support section of the stage while a substrate installation section is inserted from a lower surface side of the tray into the substrate housing hole, thereby installing the lower surfaces of the plurality of the substrates housed in the substrate housing hole, on a substrate installation surface which is an upper end surface of the substrate installation section, and generating plasma in the chamber.
According to the plasma processing apparatus and the plasma processing method in the present invention, not the one but the plurality of the substrates are housed in the substrate housing hole in the tray, and the plurality of the substrates transferred from the substrate support section of the substrate housing hole are installed on the substrate installation surface of the substrate installation section in the stage, so that the high shape controllability and the favorable productivity can be both realized while the device is prevented from being increased in size.
Referring to
Referring to
The three substrate housing holes 4A to 4C in the tray 3 are arranged in a row (a Y-axis direction in
A substrate support section 11 is provided around a whole circumference of a hole wall of each of the substrate housing holes 4A to 4C. Referring to
In each of the substrate housing holes 4A to 4C, the three substrates 5 are housed. That is, according to this embodiment, the nine substrates 5 are arranged in the tray 3 in a matrix shape of 3×3. An outer edge section of a lower surface 5b of the substrate 5 is supported by the support surface 11a of the substrate support section 11. As described above, the substrate housing holes 4A to 4C are formed so as to penetrate in the thickness direction. Therefore, upper surfaces 5c of the substrates 5 housed in the substrate housing holes 4A to 4C are exposed when viewed from the upper surface 3a side of the tray 3, and the lower surfaces 5b of the housed substrates 5 are also exposed when viewed from the lower surface 3b side of the tray 3.
The three substrates 5 housed in each of the substrate housing holes 4A to 4C are arranged in such a manner that their sides (abutment sections) 5a abut on each other and arranged to be closely adjacent to each other. That is, the three substrates 5 housed in each of the substrate housing holes 4A to 4C are arranged in a row (an X-axis direction in
As for the three substrates 5 housed in each of the substrate housing holes 4A to 4C, their outer edge sections of the lower surfaces 5b are supported by the support surface 11a of the substrate support section 11 as described above, and in addition, their centers are supported by deflection prevention rods (deflection prevention members) 12A, 12B, and 12C. According to this embodiment, one of the rods 12A to 12C is provided with respect to each substrate 5. Each of the rods 12A to 12C in this embodiment is a substantially straight rod having rigidity so as to be able to support the substrate 5 and circular in cross-section. Each of the rods 12A to 12C is provided so as to cross the three substrate housing holes 4A to 4C. The upper surface 3a of the tray 3 has three groups of retention grooves in which one group includes linear retention grooves 13a and 13b provided in the outer frame 7A and 7B, and retention grooves 13c and 13d provided in the middle frames 8A and 8B. The retention grooves 13a to 13d in the one group are linearly arranged in a direction (the Y-axis direction in
As for the center substrate 5 among the three substrates 5 housed in each of the substrate housing holes 4A to 4C, the opposed pair of sides 5a (pair of sides 5a opposed in the Y-axis direction in FIG. 2) is supported from the lower surface 5b by the support surface 11a of the substrate support section 11. In addition, as for the substrate 5 on each side among the three substrates 5 housed in each of the substrate housing holes 4A to 4C, the opposed pair of sides 5a (pair of sides 5a opposed in the Y-axis direction in
After the three substrates 5 have been housed in each of the substrate housing holes 4A to 4C, the substrate housing holes 4A to 4C are not covered with the substrates 5 and penetrate from the upper surface 3a to the lower surface 3b in sections corresponding to the four chamfered corners of the substrates 5. Thus, a plurality of (eight in total in this embodiment) block plates 14 are mounted on the upper surface 3a of the tray 3 so as to cover the penetrating sections corresponding to the chamfered sections, and be configured and positioned so as not to interfere with the substrate 5.
Referring to
The stage 21 is arranged on a metal block 24, and the metal block 24 is housed in a base section 25. The metal block 24 is electrically connected to a second high-frequency power supply section 19B and functions as a lower electrode.
Referring to
Three raised substrate installation sections 27A, 27B, and 27C each having a roughly rectangular island shape in planar view are provided in the upper surface 21a of the stage 21 so as to correspond to the substrate housing holes 4 in the tray 3. A substantially horizontal upper end surface of each of the substrate installation sections 27A to 27C functions as a substrate installation surface 28 on which the three substrates 5 transferred from the corresponding one of the substrate housing holes 4A to 4C in the tray 3 (from the substrate support section 11, and the rods 12A to 12C) are installed. A height from the upper surface 21a of the stage 21 to the substrate installation surface 28 is set to be sufficiently greater than a height from the lower surface 3b of the tray 3 to the support surface 11a of the substrate support section 11. A side wall 29 of each of the substrate installation sections 27A to 27C has an inclination fitted to the inclined surface 11b of the substrate support section 11.
Three housing grooves 31A to 31C are provided in each of the substrate installation sections 27A to 27C to receive and house the rods 12A to 12C, respectively when the tray 3 is installed on the stage 21. The three housing grooves 31A to 31C extend in parallel to each other in the same direction (the Y-axis direction in
As conceptually shown in
Referring to
Referring to
Lift pins 40 are provided in the chamber 2 in such a manner that they penetrate the base section 25, the metal block 24, and the stage 21, and are driven by a drive device 39 so as to be lifted up and down.
A controller 41 controls operations of the components of the dry etching apparatus 1, such as the first and second high-frequency power supplies 19A and 19B, the process gas source 22, the heat-transfer gas source 38, the decompression mechanism 23, the cooling device 34, the drive power supply 33, and the drive device 39.
Next, operations of the dry etching apparatus 1 in this embodiment will be described.
First, the three substrates 5 are housed in each of the three substrate housing holes 4A to 4C in the tray 1. The substrates 5 supported by the substrate support section 11 and the rods 12A to 12C in the tray 3 are exposed on the lower surface 3b of the tray 3 in the substrate housing holes 4A to 4C. The outer edge section of the lower surface 5b of the substrate 5 is supported by the support surface 11a of the substrate support section 11, and in addition, the center thereof is supported by the rods 12A to 12C. As a result, a deflection due to an own weight of the substrate 5 (which is noticeable in the vicinity of its center especially in planar view) can be surely prevented.
The tray 3 housing the substrates 5 is conveyed into the chamber 2, and received by the lift pins 40 whose tip ends project to a position sufficiently above the upper surface 21a of the stage 21. That is, as shown in
Then, the lift pins 40 are lowered, and the tray 3 is lowered toward the stage 21. The inclined surface 6a of each of the outer frames 6A to 7C is guided by the guide surface 26a of the tray guide 26 of the stage 21, so that the tray 3 is smoothly lowered while keeping an appropriate posture with respect to the stage 21. Referring to
While the tray 3 is lowered toward the stage 21, the substrate installation sections 27A to 27C of the stage 21 enter the corresponding substrate housing holes 4A to 4C in the tray 3 from the side of the lower surface 3b of the tray 3. While the tray 3 comes close to the stage 21, the substrate installation surfaces 28 as the tip ends of the substrate installation sections 27A to 27C enter the substrate housing holes 4A to 4C toward the upper surface 3a of the tray 3. In addition, the rods 12A to 12C in the tray 3 enter the housing grooves 31A to 31C, respectively in the substrate installation sections 27A to 27C.
As shown in
Then, a DC voltage is applied from the drive power supply 33 to the electrostatic chucking electrode 32, and the three substrates 5 are electrostatically chucked onto the substrate installation surface 28 of each of the substrate installation sections 27A to 27C. Then, the heat-transfer gas is supplied from the heat-transfer gas source 38 through the supply holes 37. After that, the process gas is supplied from the process gas source 22 to the chamber 2, and a predetermined pressure is maintained in the chamber 2 by the decompression mechanism 23. Then, the high-frequency voltage is applied from the high-frequency power supply 19A to the antenna 17 to generate the plasma in the chamber 3, and a bias power is supplied from the high-frequency power supply 19B to the metal block 24 provided on the side of the stage 21. The substrates 2 are etched by the plasma.
During the etching, the metal block 24 is cooled by the refrigerant circulated in the refrigerant flow path 35 by the refrigerant circulation device 36, so that the substrates 5 held on the substrate installation surfaces 28 of the substrate installation sections 27A to 27C in the stage 21 are cooled. As described above, the lower surface 5b of the substrate 5 is directly installed on the substrate installation surface 28 without having the tray 3 between them, and held with a high degree of adhesion. Therefore, heat conductivity is high between the substrate 5 and the substrate installation surface 28 with the heat-transfer gas provided between them. As a result, the substrates 5 held on the substrate installation surface 28 of each of the substrate installation sections 27A to 27C can be cooled with a high degree of cooling efficiency, and a temperature of the substrate 2 can be controlled with high precision.
In addition, since the three substrates 5 can be housed in each of the three substrate housing holes 4A to 4C in the one tray 3, and the nine substrates 5 in total can be installed on the stage 21, a batch process can be performed and preferable productivity can be provided.
In addition, not one but three substrates 5 are housed in each of the substrate housing holes 4A to 4C in the tray 3, and the three substrates 5 transferred from the substrate support section 11 of each of the corresponding substrate housing holes 4A to 4C are installed on the substrate installation surface 28 of each of the substrate installation sections 27A to 27C in the stage 21. Since the plurality of the substrates 5 are housed in the substrate housing holes 4A to 4C in the tray 3, the tray 3 can be prevented from being increased in size, and therefore the dry etching apparatus can be prevented from being increased in size. Hereinafter, this point will be described. For example, in a case where the substrate housing hole capable of housing the one substrate 5 only is provided in the tray 3, the tray 3 needs to have frame sections for defining the nine substrate housing holes, so that the tray 3 is inevitably increased in size. In addition, when the tray 3 is increased in size, a width and a thickness of the frame section need to be increased to ensure strength and rigidity, so that its weight is also increased. Meanwhile, according to this embodiment, since the three substrate housing holes 4A to 4C each capable of housing the three substrates 5 are employed, the tray 3 has only the outer frames 6A to 7B and the two middle frames 8A and 8B to define the substrate housing holes 4A to 4C, so that the tray 3 can be prevented from being increased in size and weight.
Still furthermore, the configuration in which not the single substrate 5 but the three substrates 5 are housed in each of the substrate housing holes 4A to 4C in the tray 3 is preferable in view of yield. Hereinafter, this point will be described. For example, in the case where only the one substrate 5 is housed in each substrate housing hole in the tray 3, the nine substrate housing holes corresponding to the number of the substrates 5 are needed, and the tray 3 needs to have the frame sections for defining the nine substrate housing holes. In this configuration, each of the substrates 5 is etched so that its four sides 5a are all surrounded by the frame-shaped sections, so that a variation in etching is generated between a center section and a peripheral section in the substrate 5 due to a loading effect. Meanwhile, according to this embodiment, etching is performed so that the three substrates 5 abut on each other and are installed on the one substrate installation surface 28 like one substrate, so that a section which is affected by the loading effect, in each substrate 5 can be substantially reduced, which can contribute to improvement in yield.
Furthermore, since the configuration is provided such that the three substrates 5 are arranged on the substrate installation surface 28 of each of the substrate installation sections 27A to 27C, the structure of the stage 21 can be simplified, compared with the case where the one substrate installation section is provided for the one substrate.
The substrates 5 are housed in each of the substrate housing holes 4A to 4C in the tray 3 under the condition that their sides 5a serving as the abutment section abut on each other, and this condition is also maintained after they have been transferred to the substrate installation surface 28 of each of the substrate installation sections 27A to 27C in the stage 21. In this respect, an area of the group of the three substrates 5 is miniaturized in planar view. In this respect also, the tray 3 and the stage 21 can be prevented from being increased in size.
As described above, according to the plasma processing apparatus in the present invention, the high shape controllability and the favorable productivity can be both realized while the device is prevented from being increased in size.
When the substrate installation surface 28 has a section which causes a change in structure or material quality, a bias execution power is changed in that section, so that etching uniformity is affected, which is not preferable. In view of this, each of the housing grooves 31A to 31C formed in the substrate installation surface 28 in each of the substrate installation sections 27A to 27C is preferably small in width and shallow in depth. That is, when each of the housing grooves 31A to 31C is small in width and shallow in depth, the change in bias execution power is minimized, and the etching uniformity can be ensured. Therefore, each of the rods 12A to 12C housed in the housing grooves 31A to 31C is preferably as thin as possible to the extent that the rigidity can be ensured to prevent the deflection from being generated in the center of each of the substrates 5 housed in the substrate housing holes 4A to 4C. For example, when each of the rods 12A to 12C is circular in cross-section like in this embodiment, a diameter of each of the rods 12A to 12C is preferably as small as possible to the extent that the rigidity capable of supporting the substrate 5 can be ensured.
The present invention is not limited to the above embodiment, and various modifications can be made.
According to the embodiment, the three substrates 5 are housed in each of the substrate housing holes 4A to 4C in the tray 3, and the three substrates 5 are installed on the substrate installation surface 28 of each of the substrate installation sections 27A to 27C. However, the number of the substrates housed in the substrate housing hole in the tray, that is, the number of the substrates installed on the substrate installation surface of the substrate installation section may be two, four, or more.
The deflection prevention member of the substrate 5 is not limited to the rods 12A to 12C in the embodiment. Its number and shape are not limited as long as the substrate 5 housed in each of the substrate housing holes 4A to 4C is surely prevented from being deflected due to its own weight while the substrate 5 is not prevented from being installed on the substrate installation surface 28 of each of the substrate installation sections 27A to 27C. For example, as another configuration, the three same rods as the embodiment may be provided with respect to each substrate 5. In a case where the substrate 5 is thick and its deflection due to its own weight is small or hardly generated, there is no need to provide the deflection prevention member such as the rod. When the deflection prevention member is not provided, there is no need to provide the retention grooves 13a to 13d in the tray 3, and there is no need to provide the housing grooves 31A to 31C in the substrate installation sections 27A to 27C, so that the device configuration can be more simplified.
The shape of the substrate is not limited to the angular substrate as long as there is an abutment section, and the plurality of the substrates can be housed in the substrate housing hole in the tray.
While the present invention has been described, taking the ICP type dry etching processing device as one example, the present invention can be applied to a RIE (reactive ion) type dry etching apparatus, a plasma processing apparatus for plasma CVD, and a plasma processing method.
Number | Date | Country | Kind |
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2011-163228 | Jul 2011 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2012/004223 | 6/29/2012 | WO | 00 | 1/16/2014 |