JP4942471B2 - Susceptor and wafer processing method using the same - Google Patents

Description

  The present invention relates to a susceptor for holding an object to be processed in a film forming apparatus such as CVD, PVD, sputtering, or an etching apparatus, and particularly to a susceptor that can be suitably used for an electrostatic chuck.

  Conventionally, in a semiconductor device manufacturing process, a semiconductor manufacturing apparatus such as a film forming apparatus that forms a thin film on a semiconductor wafer (hereinafter simply referred to as a wafer) or an etching apparatus that performs an etching process is used. Such a semiconductor manufacturing apparatus uses a susceptor to hold a semiconductor wafer.

  For example, a susceptor 801 shown in FIG. 7 has a plate-like body 802 made of ceramic, the upper surface of which is a mounting surface 803 on which the wafer W is placed, and a pair of electrostatic adsorption electrodes 804a and 804b on the lower surface. And a base member 807 made of metal joined to the lower surface side of 802. A gas supply hole 808 that penetrates the plate-like body 802 and the base member 807 is provided in the peripheral portion of the placement surface 803. After the wafer W is placed on the placement surface 803, an electrostatic force is generated by applying a voltage between the pair of electrostatic attraction electrodes 804a and 804b, and the wafer W can be attracted to the placement surface 803. Further, by supplying a heat conductive gas such as helium to the minute gap between the wafer W and the mounting surface 803 from the gas supply hole 808, the thermal conductivity between the wafer W and the mounting surface 803 is increased, The surface temperature was uniform.

  However, when such a susceptor 801 is repeatedly exposed to various reaction gases used for film formation or etching using plasma in a semiconductor manufacturing process, the side surface of the adhesive layer 811 is eroded by plasma or the like, and particles are generated. In addition, when erosion progresses, there is a risk that dielectric breakdown may occur between the electrostatic adsorption electrodes 804a and 804b and the plasma. Further, erosion of plasma or the like causes a hole in the adhesive layer 811 around the gas supply hole 808, from which a heat conductive gas such as helium leaks, lowering the degree of vacuum in the chamber and reducing the yield of the product. There is a possibility that such a problem may occur.

  Therefore, in order to solve the above problem, the adhesive layer 914 made of plasma or the like is formed on the side surface of the electrostatic chuck 901 in which at least the adhesive layer 914, the electrode 904, and the adsorption layer 902 are laminated on the base member 907 as shown in FIG. There has been proposed an electrostatic chuck 901 provided with an erosion preventing insulator 905 for preventing erosion (see Patent Document 1). The adhesive layer 914 can add a rubber component to the adhesive to impart elasticity to the adhesive layer 914, and can prevent distortion of the adsorption layer 902 due to elasticity even when a volume change occurs in the adhesive layer 914.

  In addition, Patent Document 2 includes an electrostatic ring having an insulating ring for protecting a resin adhesive layer on a side surface of an electrostatic chuck in which a plate-like body is bonded on a base member using a resin adhesive. A chuck device is disclosed.

In Patent Document 3, an electrostatic chuck portion having an electrostatic chucking electrode and a base member are bonded to a plate-like body by adhesion, and then a hard adhesive is injected around the periphery and cured. An electrostatic chuck characterized in that is disclosed.
JP 2000-114358 A JP 2003-179129 A JP 2003-168725 A

  However, Patent Document 1 uses an adhesive containing a fluorine-based resin or a silicone-based resin as a film-like material containing a fluorine-based resin or a silicone-based resin as an anti-erosion insulator for preventing erosion due to plasma. However, there is a problem that the mounting surface on which the substrate is placed is deformed when heated by plasma or etching gas irradiated from above. Further, since plasma and etching gas irradiated from above are repeatedly exposed to the adhesive, there is a problem that particles are generated due to the erosion of the adhesive.

  In Patent Document 2, a concave portion or a convex portion is provided in a ring shape along the outer periphery of the plate-like body on the side surface of the electrostatic chuck, and an insulating ring is disposed so as to engage with the concave portion or the convex portion. Although it has been proposed, in order to provide a ring-shaped recess or projection on the outer periphery of the plate-like body, it is necessary to increase the thickness of the plate-like body and to process the recess or projection by grinding or the like. There was a problem of increasing costs. In addition, by forming a concave portion or a convex portion, a corner portion is formed in the stepped portion, and the plate-like body is caused by the difference between the thermal expansion of the plate-like body and the thermal expansion of the base plate by heating such as drying when joining the base plate. When warping occurs, stress concentrates at the corners and there is a risk of cracks and breakage.

  In addition, along with the miniaturization of semiconductor circuit line widths, there is a tendency for high-power plasma and high processing temperature, so that further improvement of plasma resistance and the wafer mounting surface side of the plate at high temperatures When the shape of the wafer mounting surface changes due to the difference in thermal expansion due to the temperature difference from the back side where the cooling is applied, an irregular gap is created between the wafer and the mounting surface, and the wafer is cooled. The amount of leakage of thermally conductive gas, such as helium, is partially changed, so that a large amount of thermally conductive gas leaks from the gap between the plate and the wafer, or the plate and wafer Since gas leaks abnormally from an unspecified gap between the wafer surface and the wafer, the in-plane temperature difference on the wafer surface increases and the etching characteristics deteriorate.

  In addition, as shown in FIG. 7, when the gas supply hole 808 is relatively located on the outer periphery, the adhesive layer 811 is eroded by repeated exposure to plasma or etching gas, and erodes to the periphery of the gas supply hole 808. As a result, there is a problem that a heat conductive gas such as helium leaks from the gas supply hole 808 to the adhesive layer.

Accordingly, in view of the above problems, the susceptor of the present invention has a plate-like body on which the substrate to be formed or etched can be placed on the upper surface, and a base bonded to the lower surface of the plate-like body via an adhesive layer. An annular ring disposed along the outer periphery of the joint portion between the member and the plate-like body and the base member, and disposed in a recess formed in either the plate-like body or the base member. and a protective member is provided with a gap in at least one of between the lower surface of the upper surface and the protective member between and the base member and the upper surface of the protective member and the lower surface of the plate-like body The protective member is characterized in that the cross-sectional shape has a step or inclination on the upper surface side which is higher on the outer peripheral side and lower on the inner peripheral side .

The susceptor of the present invention includes a plate-like body on which a substrate to be film-formed or etched can be placed on the upper surface, a base member bonded to the lower surface of the plate-like body via an adhesive layer, Plate
And an annular protective member disposed along the outer periphery of the joint between the base member and the annular member disposed in the recess formed across the plate-like body and the base member. A gap is provided between at least one of the lower surface of the plate-like body and the upper surface of the protective member and between the upper surface of the base member and the lower surface of the protective member, and the protective member has a cross-sectional shape. The upper surface side has a step or inclination which is high on the outer peripheral side and low on the inner peripheral side .

  Moreover, the outer periphery of the said protection member is located in the same or inner side as the outer periphery of the said plate-shaped object, It is characterized by the above-mentioned.

  Moreover, the susceptor of the present invention is characterized in that, in each of the above-described configurations, the Young's modulus of the protective member is larger than the Young's modulus of the adhesive layer.

  The susceptor of the present invention is characterized in that, in each of the above structures, the protective member is made of a fluororesin.

  The susceptor according to the present invention is characterized in that, in each of the above-described configurations, the protective member is made of ceramics.

  In the susceptor according to the present invention, the gap is provided between the lower surface of the plate-like body and the upper surface of the protection member in each of the above configurations.

  Moreover, the susceptor of the present invention is characterized in that, in each of the above-described configurations, the adhesive layer is surrounded by the protective member.

  Moreover, the susceptor of the present invention is characterized in that, in each of the above-described configurations, the gap is filled with an adhesive.

  The susceptor of the present invention is characterized in that, in each of the above-described configurations, the elongation percentage of the adhesive is 100% or more. The elongation rate at this time is a value obtained by pulling the unit-length adhesive cured body with a constant force and dividing the amount of elongation until the adhesive breaks by the dimension before pulling.

  The susceptor according to the present invention is characterized in that, in each of the above-described configurations, an electrode for electrostatic attraction is formed inside the plate-like body or between the plate-like body and the base member. It is.

  Moreover, the susceptor of the present invention is characterized in that, in each of the above-described configurations, a heater is formed inside the plate-like body or between the plate-like body and the base member.

  The present invention also relates to a wafer processing method, comprising: placing a wafer on the upper surface of the plate-like body of the susceptor; applying a voltage to the electrostatic adsorption electrode to adsorb the wafer; A film forming process using plasma or an etching process using plasma is performed.

  The present invention also relates to a wafer processing method, wherein a wafer is placed on the upper surface of the plate-like body of the susceptor and a voltage is applied to the electrostatic chucking electrode to suck the wafer and the heater electrode to the wafer. After the wafer is heated, the wafer is subjected to a semiconductor thin film plasma deposition process or plasma etching process.

The susceptor of the present invention includes a plate-like body on which a substrate to be formed or etched can be placed on an upper surface, a base member bonded to the lower surface of the plate-like body via an adhesive layer, and the plate-like body A ring formed along the outer periphery of the joint between the body and the base member, formed on either the plate-like body or the base member, or formed over the plate-like body and the base member and an annular protective member disposed in a recess that is, the upper surface of and between the base member and the upper surface of the protective member and the lower surface of the plate-like body and the lower surface of the protective member A gap is provided in at least one of the gaps, and the protective member has a step or slope on the upper surface side which is higher on the outer peripheral side and lower on the inner peripheral side. Without pushing up the plate, No deforming the mounting surface put. In addition, even when used in a plasma atmosphere, the plasma does not easily enter the adhesive layer through the gap, so that the adhesive layer is not eroded and the generation of particles is small.

  In the susceptor of the present invention, in the above configuration, the adhesive layer can be covered by forming the concave portion in either the plate-like body or the base member, so that the adhesive layer is exposed to plasma. Can be prevented. Furthermore, in the said structure, when the said recessed part is formed over the said plate-shaped body and the said base member, it becomes difficult to expose an adhesive layer to plasma further, and is preferable.

  In addition, if the outer periphery of the protective member is located at the same position as or on the inner side of the outer periphery of the plate-like body, the generation of particles can be prevented because the plasma hardly hits the protective member.

  In the susceptor of the present invention, in each of the above-described configurations, the force for pushing up the plate-like body is small when the protective member has a step or slope whose cross-sectional shape is high on the outer peripheral side and low on the inner peripheral side. Therefore, deformation of the mounting surface can be prevented.

  Moreover, in each said structure, since the deformation | transformation of the said protection member can be prevented when the Young's modulus of the said protection member is larger than the Young's modulus of the said adhesive bond layer, it is less exposed to plasma.

  In addition, it is preferable that the protective member is made of a fluororesin because it has a corrosion resistance against plasma and thus the generation of particles is reduced.

  Further, when the protective member is made of fluororesin or ceramics, precise processing can be easily performed, so that a highly accurate protective member can be manufactured. And it becomes easy to adjust the said clearance gap, a deformation | transformation of a mounting surface can be prevented and generation | occurrence | production of a particle can be prevented.

  Further, in each of the above configurations, when the gap is filled with an adhesive, corrosion of the adhesive layer is suppressed and an increase in leakage current between the electrode for electrostatic attraction and the base member is prevented, and insulation is maintained for a long time. Can be maintained across. In addition, even if the use temperature rises, there is little change in the shape of the mounting surface, and the amount of heat conductive gas such as helium can be made uniform, so that the temperature distribution on the wafer surface can be kept uniform. Further, since the erosion of the adhesive layer can be prevented, the gas supply hole is not eroded, so that a susceptor in which the amount of leakage of the heat conductive gas such as helium does not change greatly can be provided.

  Further, if the elongation percentage of the adhesive is 100% or more, the force for pushing up the plate-like body becomes small and deformation of the mounting surface can be prevented, so that the gas flow rate leaking from between the wafer and the mounting surface is the temperature. Can be prevented from changing.

  In each of the above-described configurations, if an electrostatic chucking electrode or heater is formed inside the plate-like body or between the plate-like body and the base member, a gas is formed between the wafer and the mounting surface. Since the heat transfer coefficient between the wafer and the mounting surface is increased, the in-plane temperature difference of the wafer is reduced. Further, since the temperature of the wafer can be adjusted by incorporating the heater, it can be used in various film forming apparatuses and etching apparatuses.

  Further, in the wafer processing method, a wafer is placed on the upper surface of the plate-like body of the susceptor, a voltage is applied to the electrostatic adsorption electrode to adsorb the wafer, and then a semiconductor thin film plasma is applied to the wafer. By performing the film formation process by plasma or the etching process by plasma, uniform film formation and uniform etching can be performed.

  Further, in the wafer processing method, the wafer is placed on the upper surface of the plate-like body of the susceptor, a voltage is applied to the electrostatic chucking electrode to suck the wafer, and the wafer is heated by the heater electrode. Then, a more uniform film formation or a uniform etching process can be performed by subjecting the wafer to a film formation process using plasma of a semiconductor thin film or an etching process using plasma.

  An embodiment of the present invention will be described by taking an electrostatic chuck for processing a wafer as an example.

  FIG. 1A is a schematic front view showing an example of the susceptor 101 of the present invention. FIG.1 (b) is a schematic sectional drawing of the XX line.

  The susceptor 101 is obtained by bonding an electrostatic chuck portion and a base member 107 via an adhesive layer 111. The electrostatic chuck portion includes a plate-like body 102 and electrostatic adsorption electrodes 104a and 104b, and has an insulating film 113 as desired.

  The plate-like body 102 has a placement surface 103 on which a substrate W to be film-formed or etched can be placed on the upper surface. The mounting surface 103 is formed on one main surface of the plate-like body 102 and can place a wafer W which is a substrate such as a semiconductor wafer. A pair of electrostatic attraction electrodes 104 a and 104 b are provided on the other main surface of the plate-like body 102. The electrostatic adsorption electrodes 104a and 104b can be covered and protected by an insulating film 113 to enhance the insulation. From the viewpoint of insulating protection, the film 113 has a larger area than the electrostatic adsorption electrode 104, and is preferably provided over almost the entire other main surface of the plate-like body.

  By providing the pair of electrodes for electrostatic attraction 104 a and 104 b on the other main surface of the plate-like body 102, the insulating layer thickness of the plate-like body 102 can be made uniform and the adsorption force in the mounting surface 103 can be made. Can be made uniform. The insulating layer thickness refers to the distance from the mounting surface 103 to the electrostatic adsorption electrodes 104a and 104b. For example, when the electrostatic adsorption electrodes 104 a and 104 b are on the other main surface of the plate-like body 102, the insulating layer thickness corresponds to the thickness of the plate-like body 102. When the electrostatic adsorption electrodes 104a and 104b are provided inside the plate-like body 102, the insulating layer thickness is the distance from the mounting surface 103 to the electrostatic adsorption electrodes 104a and 104b.

  In FIG. 1B, a large gap is drawn between the mounting surface 103 and the wafer W. However, when a voltage is applied to the electrostatic chucking electrodes 104a and 104b, the wafer W is mounted. Adsorbed on the surface 103.

  As the base member 107, one having a high thermal conductivity can be adopted, and for example, a metal can be used. The lower surface of the electrostatic chuck portion 107 including the plate-like body 102 and the electrostatic chucking electrodes 104 a and 104 b and the upper surface of the base member 107 are bonded by an insulating adhesive layer 111.

  The peripheral portion 103 a of the mounting surface 103 is provided with a plurality of gas supply holes 108 penetrating the electrostatic chuck portion and the base member 107, and when the wafer W is sucked and held on the mounting surface 103, the mounting surface Gas is sealed between the mounting surface 103 outside the gas groove 112 and the peripheral portion 103a of the wafer W, and a thermally conductive gas such as helium is supplied through the gas supply hole 108 provided in the peripheral portion of the mounting surface 103. Then, the gap between the wafer W and the mounting surface 103 is filled with gas, and heat transfer is increased by the filling gas, so that the wafer W can be cooled uniformly.

  Further, the susceptor 101 of the present invention has an annular recess 114 along the outer periphery of the joint between the plate-like body 102 and the base member 107, and has an annular protection member 105 disposed in the recess 114. A gap 106 is provided between at least one of the lower surface of the cylindrical body 102 and the upper surface of the protective member 105 and between the upper surface of the base member 107 and the lower surface of the protective member 105. 2A and 2B are schematic partial enlarged views showing a portion A in FIG. A concave portion 114 is provided below the outer peripheral portion of the plate-like body 102 made of ceramic having good plasma resistance, and the protective member 105 is disposed in the concave portion 114, so that the base member 107 is attached to the outer peripheral portion of the plate-like body 102. Even when the guard ring 115 for protecting from plasma is installed, the plasma can enter the gap between the plate-like body 102 and the guard ring 115 so that the base member 107 can be kept at a distance so that it is difficult to be exposed to the plasma. It is possible to protect the agent layer 111 from being directly exposed to plasma.

  In addition, by forming a gap 106 between at least one of the lower surface of the plate-like body 102 and the upper surface of the protective member 105 or between the upper surface of the base member 107 and the lower surface of the protective member 105, the film forming process of the wafer W is performed. When the temperature rises in the etching process, the protective member 105 expands in the longitudinal direction (vertical direction in FIG. 1), and there is no possibility that the outer peripheral portion of the plate-like body 102 is pushed up. It is possible to suppress the change in the shape of the peripheral portion 103a of the substrate and to increase the leakage of helium gas without changing the sealing performance of the gas filled between the wafer W and the mounting surface 103.

  The gap 106 is preferably formed in the range of 0.01 to 0.1 mm. Moreover, it is more preferable to form in the range of 0.01-0.05 mm. By setting the gap 106 within the above range, the protective member 105 is restrained from pushing up the outer peripheral portion of the plate-like body 102 even if it extends in the vertical direction due to thermal expansion, and the change in the shape of the mounting surface 103 is reduced. In addition, it is easy to suppress an increase in the amount of helium gas leakage. Further, it is possible to effectively suppress generation of particles and dielectric breakdown due to plasma entering from the gap 106 and eroding the adhesive layer 111.

  FIGS. 3A, 3B, and 3C are schematic partial enlarged views showing other forms of the concave portion 114 of the A portion in FIG. As shown in FIGS. 3A and 3B, the recess 114 is preferably formed in either the base member 107 or the peripheral portion of the plate-like body 102. As shown in FIG. 3A, when the recess 114 is formed around the base member 107, it is effective when the thickness of the plate-like body 102 is as thin as 2 mm or less. Moreover, when the recessed part 114 as shown in FIG.3 (b) is formed in the periphery of the plate-shaped body 102, it is especially effective when the thickness of the plate-shaped body 102 is 5 mm or more. In FIG. 3B, the adhesive layer 111 can be completely covered with the protective member 105, and the adhesive layer 111 can be prevented from being directly exposed to the plasma atmosphere. Can be protected.

  Further, as shown in FIG. 3C, the recess 114 is preferably formed across the plate-like body 102 and the base member 107. This is particularly effective when the thickness of the plate-like body 102 is 2 to 5 mm. In FIG. 3C, since the adhesive layer 111 can be completely covered with the protection member 105, the adhesive layer 111 can be more reliably protected from plasma.

  In addition, when the protective member 105 is disposed in the concave portion 114, it is preferable that the outer periphery of the protective member 105 is located on the same side as or on the inner side of the outer periphery of the plate-like body 102. This is because when the protective member 105 protrudes from the outer periphery of the plate-like body 102, the corners of the protective member 105 may be corroded by plasma to generate particles, but the outer periphery of the protective member 105 is the outer periphery of the plate-like body 102. The corrosion of the protective member 105 can be suppressed by being located at the same or inside.

  FIG. 4 is a schematic view showing an example of a cross-sectional shape of the protective member 105 provided in the susceptor 101 of the present invention. At this time, as shown in FIG. 4A, it is preferable that the cross-sectional shape of the protective member 105 has a step on the upper surface side that is higher on the outer peripheral side and lower on the inner peripheral side. The reason for this is that when the temperature of the susceptor 101 becomes high and the protective member 105 expands due to thermal expansion beyond the gap 106, the protective member 105 is reduced in contact with the plate-like body 102, thereby reducing the protective member 105. This is because even if 105 extends upward, the force for pushing up the plate-like body 102 can be reduced. Therefore, the deformation of the mounting surface 103 can be reduced, and the penetration of plasma into the adhesive layer 111 from the outer periphery can be suppressed.

  Furthermore, as shown in FIGS. 4B to 4D, it is preferable that the cross-sectional shape of the protective member 105 has a slope on the upper surface side that is higher on the outer peripheral side and lower on the inner peripheral side. Similarly to the above, when the temperature of the susceptor 101 increases and the protective member 105 expands by thermal expansion beyond the gap 106, the protective member 105 is moved upward by reducing the area in contact with the plate-like body 102. This is because even if the plate-like body 102 is extended, the force for pushing up the plate-like body 102 is reduced, and deformation of the placement surface 103 can be suppressed.

  Further, the Young's modulus of the protective member 105 is preferably larger than the Young's modulus of the adhesive layer 111. Even when the adhesive partially flows into the gap 106 between the plate-like body 102 and the protective member 105 when the plate-like body 102 is bonded to the base member 107 via the adhesive layer 111, the Young's modulus of the protective member 105 is increased. Since the Young's modulus of the adhesive layer 111 is larger than the Young's modulus of the adhesive layer 111, the adhesive layer 111 can absorb the elongation even when the operating temperature rises in the wafer W processing process and the protective member 105 extends upward due to thermal expansion. Therefore, since the cross-sectional shape of the protective member 105 does not deform in a distorted manner and does not protrude from the outer periphery of the plate-like body 102, the protective member 105 can be prevented from being exposed to plasma.

  The material of the protective member 105 is preferably made of a fluororesin. Due to the corrosion resistance to plasma, the generation of particles is reduced. In particular, it is preferable that the fluororesin is made of a Teflon (registered trademark) resin having excellent plasma resistance. Further, Teflon (registered trademark) resin is preferable because it can be easily machined precisely, and has excellent dimensional accuracy and can be easily machined into the cross-sectional shape of the protective member 105 as shown in FIG. Precise machining makes it easy to precisely adjust the gap, and the deformation of the mounting surface can be more effectively suppressed.

  Before the plate member 102 is bonded to the base member 107, the protective member 105 made of fluororesin or the like is processed so that the inner peripheral diameter of the protective member 105 is slightly smaller than the inner peripheral diameter of the recess 114, and is about 100 ° C. It is preferable to fix by a shrinking method in which fitting is performed after heating and holding at temperature to cause thermal expansion to expand larger than the inner diameter of the recess 114. Then, a desired shape can be obtained by processing the outer diameter and thickness by lathe processing or the like. This is an effective method for preventing the generation of particles because it can be fixed without using an adhesive or the like.

The protective member 105 is preferably made of ceramics. In particular, it is effective to use ceramics whose main component is at least one of Al ₂ O ₃ , SiC, AlN or Si ₃ N ₄ because higher corrosion resistance can be obtained. Among these, it is preferable to use a ceramic sintered body mainly composed of Al ₂ O ₃ or AlN from the viewpoint of corrosion resistance against halogen-based corrosive gas or plasma. Since these ceramic sintered bodies mainly composed of Al ₂ O ₃ or AlN are brittle materials, the outer dimensions and thickness dimensions can be processed with an accuracy of 10 microns or less. Precise processing can be easily performed such that the cross-sectional shape of 105 and the outer periphery of the protective member 105 are the same as or inward of the outer periphery of the plate-like body 102.

  FIG. 5 is a schematic cross-sectional view showing the formation position of the gap provided in the susceptor of the present invention. As shown in FIG. 5A, the gap 106 is preferably provided between the lower surface of the plate-like body 102 and the upper surface of the protection member 105. This is because there is no risk of contact with the plate-like body 102 even if the use temperature rises in the processing step of the wafer W and the protective member 105 extends upward due to thermal expansion or the protective member 105 extends due to the gap 106. This is because there is no possibility of pushing up the plate-like body 102. Further, as shown in FIG. 5B, even if the gap 106 is provided between the lower surface of the protective member 105 and the upper surface of the base member 107, the same effect as that of the structure of FIG.

  Moreover, it is preferable that the edge part of the adhesive bond layer 111 is surrounded by the protective member 105 in an annular shape. As a result, even when the susceptor 101 of the present invention is used in an environment under plasma, the adhesive layer 111 is shielded from the plasma by the protective member 105, and the erosion of the adhesive layer 111 can be suppressed, and the particles caused by the plasma can be suppressed. Can be suppressed.

  FIG. 6 is a schematic view showing an example of a cross-sectional shape of the protective member 105 provided in the susceptor 101 of the present invention. As shown in FIGS. 6A and 6B, the gap 106 is preferably filled with an adhesive 215. This is because, when the gap 106 is not filled with the adhesive 215, the plasma concentrates on the corners of the plate-like body 102 and the protection member 105 forming the gap 106 under the plasma, and the plate-like body 102 or the protection member 105. In order to suppress the generation of the particles, the gap 106 is filled with the adhesive 215 to make the surface smooth without the corners. Concentration can be suppressed and generation of particles can be reduced.

  At this time, the adhesive 215 filled in the gap 106 is preferably a silicone adhesive that has excellent plasma resistance and becomes a rubber-like elastic body after curing. The reason for this is that when the use temperature rises in the processing step of the wafer W and the protective member 105 extends upward due to thermal expansion, the silicone adhesive, which is an elastic body, relieves the pushing force of the protective member 105, This is because the deformation can be suppressed. Specifically, the adhesive 215 is preferably “TSE-3360” manufactured by GE Toshiba Silicone.

  The adhesive 215 preferably has an elongation percentage after curing of 100% or more. This is because the adhesive 215 is easily contracted even when the operating temperature is increased in the process of processing the wafer W and the protective member 105 is thermally expanded to extend in the vertical direction, thereby relieving the stress pushed up to the plate-like body 102. This is to prevent the plate-like body 102 from being pushed up. Conversely, if the elongation percentage of the adhesive 215 after curing is less than 100%, when the protective member 105 extends in the longitudinal direction due to thermal expansion, the amount of shrinkage of the adhesive 215 is reduced and the plate-like body 102 is pushed up. This is because the shape of the mounting surface 103 is deformed and a gap is formed between the wafer W and the mounting surface 102, so that helium gas leaks and the surface temperature of the wafer W cannot be made uniform. . The elongation rate after curing of the adhesive is a value obtained by pulling the cured adhesive body of unit length with a constant force and dividing the amount of elongation until the adhesive breaks by the dimension before stretching. Moreover, it shows that it is soft as an elastic body, and it is easy to shrink | compress with respect to compression, so that elongation rate is large.

  Further, it is preferable that the electrostatic attraction electrode 104 is formed inside the plate-like body 102 or between the plate-like body 102 and the base member 107. This is because, by adsorbing the wafer W to the mounting surface 103 by electrostatic force, the gap between the wafer W and the mounting surface 103 can be reduced uniformly, and the leakage of helium gas can be reduced. This is because the surface temperature of the wafer W can be made uniform. In particular, since the wafer W is heated due to heat generated by the plasma under the plasma, the wafer W and the mounting surface 103 are used to adjust the temperature by adsorbing the wafer W to the mounting surface 103 by electrostatic force. This is because it is easy to cool the wafer W by introducing a heat conductive gas such as helium. If the amount of helium gas leakage increases, the wafer W cannot be uniformly cooled, and the surface temperature of the wafer W becomes non-uniform, which may reduce the yield of the film forming process or the etching process.

  The electrostatic adsorption electrode 104 can be formed inside the plate-like body 102. This is because an electrostatic adsorption electrode 104 is formed on a ceramic green sheet by a printing method, and another ceramic green sheet is overlaid to form a laminate of a plurality of ceramic green sheets, which are then brought into close contact with a press. After producing the molded body, the plate-like body 102 can be obtained through a binder removal process, a firing process, and a grinding process. It is preferable to embed the electrostatic chucking electrode 104 in the plate-like body 102 in this way because corrosion due to plasma can be suppressed.

  As another means for forming the electrostatic chucking electrode 104, the electrostatic chucking electrode 104 is formed on the surface opposite to the mounting surface 103 of the plate-like body 102, and the electrostatic chucking electrode 104 is replaced with the insulating film 113. Can be used as a means for generating static electricity. At this time, the electrode 104 for electrostatic attraction formed on the other main surface of the plate-like body 102 is made of a metal such as Ni, Ti, Ag, Cu, Au, Pt, Mo, Mn, or an alloy thereof, or TiN, TiC, It is made of a conductive layer of WC and has a thickness of 0.1 μm or more, and can be deposited by film forming means such as sputtering, ion plating, vapor deposition, plating, CVD, etc., and then blasted Electrostatic chucking electrode 104 can be formed by removing unnecessary portions of the conductor layer by etching. By forming the electrostatic chucking electrode 104 on the surface of the plate-like body 102 in this way, the distance between the electrostatic chucking electrode 104 and the mounting surface 103 becomes more constant, and within the surface of the mounting surface 103. It becomes easy to manufacture an electrostatic chuck having a constant attraction force.

  A heater is preferably formed inside the plate-like body 102 or between the plate-like body 102 and the base member 107. With this configuration, since the wafer W can be heated to an arbitrary temperature, the susceptor 101 can be used in various semiconductor manufacturing processes, and the single susceptor 101 can be used for various processes. Can be used.

  The heater can be formed inside the plate-like body 102 in the same manner as the electrostatic adsorption electrode 104. This is because the electrode 104 is formed on a ceramic green sheet by a printing method, another ceramic green sheet is stacked, a laminate of a plurality of ceramic green sheets is formed, and then adhered by a press, debinding, The plate-like body 102 can be obtained through the firing process and the grinding process.

  In each of the above configurations, if the electrostatic chucking electrode 104 or the heater is formed inside the plate-like body 102 or between the plate-like body 102 and the base member 107, the wafer W and the mounting surface 103 are arranged. Since gas can be supplied and filled in between, the heat transfer coefficient between the wafer W and the mounting surface 103 is increased, and the in-plane temperature difference of the wafer W is preferably reduced. Moreover, since the temperature of the wafer W can be adjusted by incorporating a heater, it can be used in various film forming apparatuses and etching apparatuses.

The plate-like body 102 is preferably a ceramic having excellent corrosion resistance, and in particular, a ceramic sintered body mainly containing at least one of Al ₂ O ₃ , SiC, AlN, and Si ₃ N ₄ is used. It is important in obtaining higher corrosion resistance. Among these, it is preferable to use a ceramic sintered body mainly composed of Al ₂ O ₃ or AlN from the viewpoint of corrosion resistance against halogen-based corrosive gas or plasma. In the case of manufacturing at a lower cost, a ceramic sintered body containing Al ₂ O ₃ as a main component is used. When heat uniformity of the wafer is required, AlN having a thermal conductivity of 100 W / (m · K) or more is used. It is preferable to use a ceramic sintered body containing as a main component.

  On the other hand, the base member 107 is made of ceramic, aluminum, cemented carbide, or a composite material of these metals and a ceramic material, and has a through-hole for taking out the lead wire 110 connected to the electrostatic adsorption electrodes 104a and 104b. Have. Further, when the base member 107 is used as a plasma electrode for generating plasma above the wafer W, a composite material of a metal and a ceramic material having a volume specific resistance value of 10 Ω · cm or less of the base member 107, Further, aluminum or super steel having a small volume resistivity is preferable. Further, when the heat of the wafer W is discharged from the base member 107 to the outside through the plate-like body 102, the thermal conductivity of the base member 107 is preferably 50 W / (m · K) or more, more preferably. Is 100 W / (m · K) or more.

  The susceptor 101 of the present invention can place the wafer W on the mounting surface 103 and apply a DC voltage to the electrostatic chucking electrodes 104 a and 104 b to electrostatically attract the wafer W to the mounting surface 103. Then, plasma can be generated above the wafer W to perform various film formation and etching on the wafer W.

  In the present embodiment, an example of a bipolar electrostatic chuck is shown as the susceptor. However, the effect of the present invention can be achieved even if a single-pole electrostatic chuck is used.

  It goes without saying that the present invention can also be applied to improvements and changes made without departing from the scope of the invention.

  Next, the manufacturing method of this invention is demonstrated.

  The plate-like body 102 is formed by processing a ceramic sintered body to a predetermined outer diameter and thickness, forming a conductor layer by plating, and removing unnecessary portions by blasting to form an electrode 104 for electrostatic adsorption. Produced by. In order to ensure insulation between the electrostatic adsorption electrode 104 and the base member 107, the electrostatic adsorption electrode 104 can be covered and protected with an insulating film such as polyimide, if desired.

  The base member 107 is made of ceramics, aluminum, cemented carbide, or a composite material of these metals and a ceramic material. A cooling water channel is provided in the interior, and a coolant is circulated to generate the plasma on the wafer W. Heat can be released outside the system. The surface of the base member 107 is preferably subjected to a surface treatment such as alumite in order to provide insulation.

  The protection member 105 is manufactured in an annular shape, and the inner diameter dimension thereof is processed to be smaller than the outer diameter dimension of the bonding surface of the base member 107, and the protection member 105 is expanded by applying heat to be larger than the outer dimension dimension of the base member 107. Press fit into place. The protective member 105 made of Teflon (registered trademark) was optimally heated and press-fitted at a temperature of about 100 ° C. Thereafter, the outer diameter of the protective member 105 is finished to be the same as or slightly smaller than the outer dimension of the plate-like body by lathe processing. Further, the end surface of the protective member 105 facing the plate-like body 102 is processed to be lower than the adhesive surface of the base member 107, and the cross-sectional shape of the protective member 105 is set so that the outer peripheral thickness is larger than the inner peripheral thickness. It is processed so as to be substantially L-shaped or tapered.

  Next, a silicone adhesive is uniformly applied to the bonding surface of the base member 107 by screen printing, and the plate-like body 102 is bonded and fixed. At this time, if a silicone adhesive is also applied to the end face of the protective member, the gap 106 can be easily filled with the adhesive.

  A plate-like body made of an aluminum nitride sintered body having a diameter of 300 mm and a thickness of 3 mm is prepared, and a Ni film is deposited on the main surface opposite to the mounting surface by plating, followed by blasting A pair of electrostatic adsorption electrodes made of a Ni film was formed by removing unnecessary portions.

  The formation position of the concave portion in which the protective member is disposed is around the upper surface of the base member. And the notch used as a recessed part was formed in the outer peripheral part of the upper surface of a base member. Next, a protective member made of Teflon (registered trademark) resin having an inner diameter smaller in the range of 20 to 100 μm than the outer diameter of the notch of the base member was produced. The protective member made of Teflon (registered trademark) is heated and held in a dryer at 100 ° C., and is press-fitted into the notch of the base member when it is larger than the outer diameter of the notch of the base member by thermal expansion. Combined. And it cut so that the upper end surface of Teflon (trademark) resin might become 30 micrometers smaller than the adhesion surface of a base member and a plate-shaped body so that a clearance gap might be provided between a plate-shaped body and a protection member. The plate-like body was bonded and fixed with a base member and a silicone adhesive, and the thickness of the plate-like body was ground to 1 mm. Further, the sample No. as shown in FIG. 1 was produced.

  Further, as a comparative example, a sample No. obtained by processing the upper end surface of Teflon (registered trademark) resin as shown in FIG. 9 having a structure similar to that of the conventional example to the same height as the bonding surface of the base member and the plate-like body. . 2 was produced.

  The outer diameters of these protective members were the same as the outer diameter dimensions of the plate-like body.

Then, each sample is adsorbed and held in a vacuum in vacuum, helium gas is supplied from the gas supply hole at room temperature at a pressure of 2666 Pa, the amount of leakage of helium gas is measured with a flow meter, and then oxygen plasma is supplied. Is irradiated with helium gas at a pressure of 2666 Pa from a gas supply hole when the temperature reaches 80 ° C. with a thermocouple (not shown) previously installed on the lower surface of the plate-like body, and helium gas is supplied with a flow meter. The amount of leakage of helium gas at room temperature and 80 ° C. was compared. These results are shown in Table 1.

  As a result, sample No. 1 provided with a gap between the plate-like body and the protective member. For No. 1, the difference in the amount of leaked helium between room temperature and 80 ° C. was 0.9 SCCM, which was almost unchanged. The reason for this is that even when the use temperature is high and the protective member extends in the thickness direction due to thermal expansion, the elongation of the protective member can be absorbed by the gap between the plate-like body and the upper end surface of the protective member. It is considered that the wafer can be satisfactorily attracted and held without changing the shape of the mounting surface.

  On the other hand, Sample No. with no gap between the plate-like body and the protective member. In No. 2, the difference in the amount of helium leakage was as large as 17.5 SCCM, and it was found that the amount of helium leakage increased as the operating temperature increased. This is because the use temperature increases, the protective member extends in the thickness direction due to thermal expansion, and pushes up the plate-like body, so that the shape of the mounting surface changes, and a minute amount is formed between the wafer and the mounting surface. It is thought that helium gas leaked from the gap. Therefore, the degree of vacuum in the chamber decreased.

  From the above results, it was found that a gap is preferably provided between the plate-like body and the protective member.

  Next, in order to verify the effect due to the formation position of the recess, the sample No. 1 in which the recess was formed in the base member as shown in FIG. 1 and Sample No. 1 in which the concave portion is formed in a plate-like body as shown in FIG. 3 and sample No. 2 formed over the plate-like body and the base member as shown in FIG. 4 were produced. At this time, sample no. No. 1 has a thickness of 1 mm, sample No. 3 is 5 mm in thickness, and sample No. The thickness of the plate-like body 4 was 3 mm.

Then, after each sample was irradiated with oxygen plasma for 100 hours under vacuum with the wafer adsorbed, the number of particles having a size of 0.1 μm or more adhering to the wafer and the number of particles having a size of 1 μm or more were determined. Measurement was performed using a particle counter. These results are shown in Table 2.

  As a result, sample no. In Nos. 1 and 3, the number of particles of 0.1 μm or more was 376 and 352, respectively. However, in the sample No. 1 in which the concave portion is formed over the plate-like body and the base member. 4 was a little less than 289.

  In addition, the number of particles of 1 μm or more is the sample No. Compared with 21 and 17 of 1 and 3, sample No. 4 was as small as 13 pieces.

  Further, when qualitative analysis of the particles was performed, sample No. Al and Si were detected from 1 and 3 particles of 0.1 μm or more. Sample No. Only Al was detected from 4 particles of 0.1 μm or more. Sample No. In addition to the fluorine component, some Si was detected from particles 1 and 3 of 1 μm or more. Sample No. Only the fluorine component was detected from 4 particles of 1 μm or more.

  From the above analysis results, the Al component of the particle is the source of aluminum nitride ceramics, which is the material of the plate-like material, the fluorine component is the source of Teflon (registered trademark) resin, which is a protective member, and the Si component is It can be inferred that the silicone adhesive is the source. Note that the amount of Si generated was much smaller than that of a conventional product without a protective member as shown in FIG.

  This can be inferred that when the concave portion is formed in a plate-like body, the plasma slightly enters from the adhesive layer through the mating surface of the protective member and the base member to erode the adhesive and generate particles. When the concave portion was formed on the base member, particles were generated from the adhesive layer through the gap. On the other hand, when the concave portion is formed over the plate-like body and the base member, it can be inferred that no particles were generated from the adhesive layer because the adhesive layer was completely covered with the protective member.

  As a result, the concave portion in which the protective member is disposed is formed on either the plate-like body or the base member, or preferably formed over the plate-like body and the base member, so that the adhesive layer is exposed to the plasma atmosphere. It was found that can be suppressed.

  Next, in order to verify the effect of the outer diameter of the protection member relative to the outer diameter of the plate-like body, a sample obtained by processing the outer diameter dimension of the protection member 1 mm larger in the radial direction than the outer diameter dimension of the plate-like body No. No. 5 and Sample No. 5 which were polished at the same time so that the outer diameter of the protective member and the outer diameter of the plate member were the same. 1 and Sample No. 1 in which the outer diameter of the protective member was processed to be 1 mm smaller in the radial direction than the outer diameter of the plate-like body. 6 was produced.

Then, after irradiating the wafer under oxygen plasma for 100 hours while adsorbing the wafer in a vacuum, the number of particles having a size of 0.1 μm or more and the number of particles having a size of 1 μm or more adhering to the wafer is measured using a particle counter. It was measured. These results are shown in Table 3.

  As a result, the number of particles having a size of 0.1 μm or more and the number of particles having a size of 1 μm or more are the same as the sample No. Sample No. 5 having the same outer diameter size for 397 and 45 in 5 Sample No. 1 with 376 and 21 with a smaller outer diameter. It was found that 6 was 342 and 16 and the outer diameter of the protective member was the same as or smaller than the outer diameter of the plate-like body.

  Further, a qualitative analysis of the particles revealed that a fluorine component was detected from particles having a size of 1 μm or more. Accordingly, it was found that particles having a size of 1 μm or more include particles from Teflon (registered trademark) resin, which is a material of the protective member. This is presumably because the protective member protruding from the outer diameter of the plate-like body is directly exposed to the plasma, so that the plasma is concentrated on the corners of the protective member and particles are easily generated. Accordingly, it was found that the outer diameter of the protective member is preferably the same as or located inside the outer periphery of the plate-like body.

  Next, sample Nos. 1 and 2 in which the cross-sectional shape of the protective member made of Teflon (registered trademark) is changed as shown in FIGS. 3 (a) and 4 (a) to (d). 1 and no. 7-10 were produced. At this time, the gap between the upper end surface of the protective member and the back surface of the plate-like body was about 10 μm. When the temperature rises, the protective member extends upward due to thermal expansion, thereby pushing up the plate to change the shape of the mounting surface. The amount of helium gas leaked from the gap between the wafer and the mounting surface was verified.

  In the verification method, as in Example 1, each sample was held by suction holding the wafer in vacuum, helium gas was supplied from the gas supply hole at room temperature at a pressure of 2666 Pa, and the amount of helium gas leaked was measured with a flow meter. Measure, then irradiate oxygen plasma and supply helium gas at a pressure of 2666 Pa from the gas supply hole when the temperature reaches 80 ° C. with a thermocouple (not shown) previously installed on the lower surface of the plate-like body Then, the amount of helium gas leaked was measured with a flow meter, and the difference in the amount of helium gas leaked at room temperature and at 80 ° C. was compared.

In addition, in order to check particles generated from the adhesive layer through the gap, particles with a size of 0.1 μm or more adhering to the wafer after being irradiated for 100 hours under oxygen plasma with the wafer adsorbed in a vacuum. And the number of particles of 1 μm or more were measured using a particle counter. These results are shown in Table 4.

  As a result, sample no. When the cross-sectional shape of the protective member such as 1 was rectangular, the difference in the amount of leaked helium gas at room temperature and 80 ° C. was 0.9 SCCM. Sample No. 7-10, the cross-sectional shape of the protective member is a helium at room temperature and 80 ° C. when the cross-sectional shape of the protective member has a step on the upper surface side that is high on the outer peripheral side and a low step on the inner peripheral side. The difference in gas leakage is 1.2 SCCM or less, and the sample No. It was slightly larger than 1.

  In the measurement of particles, sample No. As shown in FIG. 1, the gap between the upper end surface of the protective member and the back surface of the plate-like body is about 30 μm. The number of particles having a size of 0.1 μm is about 10 μm compared to 376 particles. Sample No. In 7-10, the number of generated particles decreased to 328 or less.

  This is because the gap is reduced to suppress the intrusion of plasma and the generation of particles from the adhesive layer.

  As a result, the cross-sectional shape of the protective member has a high step on the outer peripheral side on the upper surface side and a low step or low inclination on the inner peripheral side, so that helium gas leakage is stable without pushing up the plate-like body even when the operating temperature rises. In addition, the gap between the upper end surface of the protective member and the back surface of the plate-like body can be reduced, so that generation of particles from the adhesive layer can be suppressed.

  Next, in order to confirm that the Young's modulus of the protective member made of Teflon (registered trademark) resin is preferably larger than the Young's modulus of the adhesive layer that joins the plate member and the base member, the Young of the adhesive layer after curing is used. Sample No. bonded with an epoxy adhesive having a modulus greater than the Young's modulus of the protective member. 11 and Sample No. bonded with a silicone adhesive having a low Young's modulus. 12 was produced. At this time, the Young's modulus of the protective member made of Teflon (registered trademark) was 0.5 GPa, the Young's modulus of the cured epoxy adhesive was 2.0 GPa, and the Young's modulus of the cured silicone adhesive was 0.002 GPa. . The shape of the protective member was as shown in FIG. 2A, and the gap between the upper end surface of the protective member and the lower surface of the plate-like body was 30 μm.

Each sample was irradiated with oxygen plasma for 100 hours under vacuum with the wafer adsorbed, and then the number of particles 0.1 μm or larger and the number of particles 1 μm or larger adhering to the wafer were measured using a particle counter. It measured using. These results are shown in Table 5.

  As a result, when compared with the number of particles having a size of 1 μm or more, Sample No. 12 has a Young's modulus of the protective member smaller than that of the adhesive layer as compared to the number of 14, the material No. 11 had 38 particles and a large number of particles.

  This is because the adhesive flowed into a part of the gap between the upper end surface of the protective member and the back surface of the plate-like body and was cured, so that the temperature rose while being irradiated with oxygen plasma, and the protective member expanded due to thermal expansion. At this time, the protective member was crushed by the adhesive having a high Young's modulus and protruded from the outer periphery of the plate-like body, so that the plasma was concentrated on the corners of the protective member, thereby generating particles.

  Thus, it has been found that the Young's modulus of the protective member is preferably larger than the Young's modulus of the adhesive that joins the plate-like body and the base member.

  Next, in order to verify that the formation position of the gap is preferably provided between the lower surface of the plate-like body and the upper surface of the protective member, the gap as shown in FIG. And a sample No. provided on the upper surface of the protective member. 13 and a sample No. formed on the lower surface of the protective member and the upper surface of the base member as shown in FIG. 14 was produced.

  As a method of forming the gap, when the gap is provided on the lower surface of the plate-like body and the upper surface of the protective member as shown in FIG. 5A, the end surface of the protective member is protruded by about 50 μm from the adhesive application surface of the base member. After processing into a state, a silicone adhesive is uniformly applied by screen printing. At this time, since the coating thickness of the adhesive is about 100 to 120 μm, the plate-like bodies can be bonded and fixed by bonding the plate-like bodies and heat-curing at about 80 ° C., and the adhesive layer shrinks appropriately. Thus, a gap of about 30 μm can be formed on the lower surface of the plate-like body and the upper surface of the protective member.

  On the other hand, when the protective member is formed on the lower surface of the protective member and the upper surface of the base member as shown in FIG. 5B, it is necessary to form a gap when the protective member is fitted to the base member. A gap can be formed by placing a spacer having a thickness of about 30 μm in advance and then fitting the protective member so as to sit on the spacer. After that, the upper surface of the protective member is processed so as to have the same height as the adhesive layer to which the plate-like body is bonded, and an adhesive is applied to press the plate-like member against the protective member. The plate-like body can be bonded and fixed by heating and curing at, and a gap can be formed between the lower surface of the protective member and the upper surface of the base member. At this time, the thickness of the plate-like body was 3 mm.

  And the flatness of the plate-like body after adhesion was measured. Flatness is measured with a three-dimensional measuring instrument by measuring 21 arbitrary points including 8 parts at an angle of 45 degrees and the center of the plate-shaped body on the mounting surface side and entering the inner side about 2 mm from the outer periphery. It is shown by the difference between the maximum value and the minimum value.

Further, the plate-like body was processed to a thickness of 1 mm by grinding to adjust the shape of the mounting surface to be a susceptor, and then the adsorption force of the mounting surface was measured. The measurement site was measured at the center and the outer periphery of the mounting surface, and the difference in adsorption force was expressed by the difference between the internal and external adsorption forces. A 1-inch square wafer was placed on the mounting surface, and the electrostatic adsorption electrode was energized to attract the wafer, and the force required to peel the wafer per unit area was defined as the adsorption force. The measurement voltage at this time was 500 V of a single electrode, and after applying the voltage for 10 seconds, the peeling was performed to measure the adsorptive power. These results are shown in Table 6.

  As a result, the sample No. 1 in which the gap was provided between the lower surface of the plate-like body and the upper surface of the protective member. In No. 13, the flatness of the plate-like body after bonding was as good as 13.7 μm. Sample No. provided with a gap between the lower surface of the protective member and the upper surface of the base member. No. 14, the flatness of the plate-like body after bonding was as large as 87.5 μm. Sample No. The planar shape of 14 plate-like bodies had a concave central portion and a convex outer peripheral portion. This is because when the plate-like body is bonded and the adhesive is heated and cured at 80 ° C., the adhesive is cured in a state where the base member is expanded in the thickness direction due to thermal expansion, and comes into contact with the protective member when returning to room temperature. It is considered that the base member contracted compared to the outer peripheral portion of the plate-like body, and the outer periphery of the plate-like body became a convex shape.

  On the other hand, the sample No. 1 provided with a gap between the lower surface of the plate-like body and the upper surface of the protective member. 13 has a warp due to shrinkage when the base member returns to room temperature, but since there is a gap between the protective member and the plate-like body, the outer peripheral portion of the plate-like body is not pushed up, so the amount of warpage is reduced. I was able to.

  And sample no. In No. 13, since the flatness of the plate-like body was as good as 13.7 μm, the difference between the inside and outside of the adsorption force was as small as 917 Pa and was substantially uniform. On the other hand, Sample No. with a flatness of the plate-like body as large as 87.5 μm. No. 14 had a large internal / external difference in adsorption force of 7810 Pa.

  Thus, it was found that the gap is more preferably provided between the lower surface of the plate-like body and the upper surface of the protection member.

    Next, a sample No. as shown in FIG. 15 was produced. The material of the protective member was Teflon (registered trademark) resin, the gap width was about 30 μm, and the filled adhesive was a silicone adhesive. The adhesive filling method is to apply a silicone adhesive to the upper surface of the protective member made of Teflon (registered trademark) in advance when bonding the plate to the base member, and then adhere the plate to the sample No. . 15 was produced.

  For comparison, a sample No. 1 not filled with an adhesive as shown in FIG. 1 was produced.

Then, after irradiating the wafer under oxygen plasma for 100 hours with the wafer adsorbed in a vacuum, a particle counter is used to determine the number of particles having a size of 0.1 μm or more and the number of particles having a size of 1 μm or more attached to the wafer. Measured. The results are shown in Table 7.

  As a result, sample no. In Sample No. 15, the number of particles having a size of 1 μm or more is 7 and the sample No. It was found that there were fewer than 21 of 1.

  This is because the exposed surface of the protective member is smoothed by filling the gap with the adhesive, and the particles generated from the protective member can be reduced because the plasma is less likely to concentrate.

  This is preferable because the generation of particles from the protective member can be suppressed by filling the gap with the adhesive.

  Furthermore, sample No. Samples with different adhesives were produced by the same production method as in No. 15. In order to confirm the effect of the elongation rate of the adhesive filled in the gap, the sample No. 1 was injected with a silicone adhesive having a different elongation rate of 50 to 250%. 16-19 were produced. These adhesives were selected from elongation catalogs of GE Toshiba Silicone and used. Specifically, “TSE 3331” was used for an elongation rate of 50%, “TSE 3330” was used for an elongation rate of 100%, “TSE 326M” was used for an elongation rate of 180%, and “TSE 3260” was used for an elongation rate of 250%.

Then, the wafer is adsorbed and held in vacuum in these samples, helium gas is supplied from the gas supply hole at a pressure of 2666 Pa at room temperature, the amount of helium gas leakage is measured with a flow meter, and then oxygen plasma is supplied. Is irradiated with helium gas at a pressure of 2666 Pa from a gas supply hole when the temperature reaches 80 ° C. with a thermocouple (not shown) previously installed on the lower surface of the plate-like body, and helium gas is supplied with a flow meter. The amount of leakage of helium gas at room temperature and 80 ° C. was compared. These results are shown in Table 8.

    As a result, Sample No. with an adhesive elongation of 50% was obtained. In No. 16, the amount of helium gas leaked increased when the temperature was high, and the difference from the amount leaked at room temperature was a little as large as 3.2 SCCM. On the other hand, Sample No. with an elongation percentage of the adhesive of 100% or more. In Nos. 17 to 19, the amount of helium gas leaked was as small as 0.6 SCCM or less even at high temperatures. This is because, when the elongation of the adhesive layer is large, the protective member does not push up the plate-like body by relaxing the adhesive layer against the elongation due to thermal expansion when the use temperature rises. It is considered that there is no deformation or a gap between the wafer and the mounting surface, and the amount of helium gas leakage does not increase. This indicates that the elongation percentage of the adhesive filling the gap is preferably 100% or more.

(A) is a schematic top view which shows an example of the susceptor of this invention, (b) is the XX schematic sectional drawing. (A), (b) is a general | schematic cross-sectional enlarged view of the A section of FIG.1 (b) of the susceptor of this invention. (A), (b) and (c) is the schematic which shows the cross-sectional shape of the recessed part provided in the susceptor of this invention. (A), (b) and (c) is the schematic which shows the cross-sectional shape of the protection member provided in the susceptor of this invention. (a) And (b) is a schematic sectional drawing which shows the formation position of the clearance gap provided in the susceptor of this invention. (A) And (b) is the elements on larger scale of the A section which provided the contact bonding layer in the clearance gap between the protective member provided in the susceptor of this invention, and a plate-shaped object. It is sectional drawing which shows an example of the conventional susceptor. It is sectional drawing which shows the other example of the conventional susceptor. It is the schematic which shows the cross-sectional shape of the recessed part provided in the conventional susceptor.

Explanation of symbols

101, 401, 501: Susceptors 102, 402, 502: Plates 103, 403: Placement surfaces 104, 404, 504: Electrodes 105, 505: Protection member 106: Gap 107, 407, 507: Base member 111: Adhesive layer 114: recess

Claims (16)

  A plate-like body on which the substrate can be placed on the upper surface, a base member joined to the lower surface of the plate-like body via an adhesive layer, and an outer periphery of a joint portion between the plate-like body and the base member An annular protective member disposed in a recess formed in either the plate-like body or the base member, and the lower surface of the plate-like body and the protective member A gap is provided between the upper surface of the base member and at least one of the upper surface of the base member and the lower surface of the protective member. A susceptor having a low step or slope.   A plate-like body on which the substrate can be placed on the upper surface, a base member joined to the lower surface of the plate-like body via an adhesive layer, and an outer periphery of a joint portion between the plate-like body and the base member An annular protective member disposed in a concave portion formed across the plate-like body and the base member, the lower surface of the plate-like body and the upper surface of the protective member And at least one of the upper surface of the base member and the lower surface of the protective member is provided with a gap, and the protective member has a step difference in cross-sectional shape on the upper surface side on the outer peripheral side and lower on the inner peripheral side. Or a susceptor characterized by having an inclination.   3. The susceptor according to claim 1, wherein an outer periphery of the protection member is located at an inner side or an inner periphery of the plate-like body.   The susceptor according to claim 1, wherein a Young's modulus of the protective member is larger than a Young's modulus of the adhesive layer.   The susceptor according to claim 4, wherein the protective member is made of a fluororesin.   The susceptor according to claim 4, wherein the protective member is made of ceramics. The gap, susceptor according to any one of claims 1 to 6, characterized in that provided between the upper surface of the lower surface and the protective member of the plate-like body.   The susceptor according to claim 1, wherein the adhesive layer is surrounded by the protective member. The susceptor according to any one of claims 1 to 8, wherein the gap is filled with an adhesive.   The susceptor according to claim 9, wherein the adhesive has an elongation percentage of 100% or more.   The susceptor according to claim 1 or 2, wherein an electrostatic adsorption electrode is formed inside the plate-like body or between the plate-like body and the base member.   The susceptor according to claim 9, wherein an electrode for electrostatic attraction is formed inside the plate-like body or between the plate-like body and the base member.   The susceptor according to claim 11, wherein a heater is formed inside the plate-like body or between the plate-like body and the base member.   The susceptor according to claim 12, wherein a heater is formed inside the plate-shaped body or between the plate-shaped body and the base member.   A wafer is placed on the upper surface of the plate of the susceptor according to claim 12, a voltage is applied to the electrostatic chucking electrode to suck the wafer, and then a semiconductor thin film is formed on the wafer by plasma. A method for processing a wafer, characterized by performing an etching process by plasma processing or plasma.   A wafer is placed on the upper surface of the plate-like body of the susceptor according to claim 14, a voltage is applied to the electrostatic adsorption electrode to adsorb the wafer, and the wafer is heated by the heater electrode. A method of processing a wafer, comprising subjecting the wafer to a film forming process using plasma of a semiconductor thin film or an etching process using plasma.

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