JP2013171901A - Substrate holding device with electrostatic chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate holding device with an electrostatic chuck that eliminates the need of a surface seal for gas supply in assembling a substrate holding device by joining an electrostatic chuck to the surface of a substrate, and is easily assembled at low costs.SOLUTION: A substrate holding device with an electrostatic chuck comprises: a chuck body 1 that is applied with a concave-convex shape on an adsorption surface with a wafer W, the chuck body 1 including a first gas passage 16 formed to communicate with the adsorption surface, and electrodes 2a and 2b; and bolts B that join a base 5 supporting the chuck body and a dielectric body facing the base. A cylinder 4 extending downward surrounding an opening edge of the first gas passage is provided integrally with and below the chuck body; a concave part 52b fitted to the cylinder via an O-ring S is formed on the base; and a second gas passage 52d communicating with the cylinder is formed on the base.

Description

  The present invention relates to a substrate holding apparatus with an electrostatic chuck.

  In order to obtain a desired device structure in the semiconductor manufacturing process, various vacuum processes such as a film forming process, an annealing process, an ion implantation process and an etching process are performed on a silicon wafer (hereinafter referred to as “wafer”) as a processing target. It is known to apply. In vacuum processing apparatuses that perform these vacuum processes, a substrate holding apparatus with a so-called electrostatic chuck may be provided to position and hold a wafer in a processing chamber and control it at a constant temperature.

  As the above-mentioned type of substrate holding device, a chuck body that is a dielectric having a structure (for example, concavo-convex shape) capable of supplying an inert gas to an adsorption surface with a wafer as an adsorbent, and an electrode embedded therein, For example, Japanese Patent Application Laid-Open No. H10-228561 is known that includes a base that supports the chuck body and is assembled with a heating unit and a cooling unit. In this case, a plurality of through-holes extending in the thickness direction are formed in the chuck body, and gas passages communicating with the respective through-holes are formed in the base, and the gas passages are used when heating or cooling the wafer. An inert gas such as argon gas or helium gas is supplied to the adsorption surface from the through hole to assist the heat transfer from the chuck body to the wafer so that the wafer can be efficiently heated or cooled.

  Further, in the above conventional example, a carbon sheet material (intermediate member) is interposed on the joint surface between the base and the electrostatic chuck in order to seal the inert gas flowing through each through hole. However, when surface sealing is performed using a sheet material, high-precision finishing is performed so that if the inert gas is surely sealed, the joint surfaces of the base and electrostatic chuck become smooth surfaces with small surface roughness. Will be necessary to increase the cost. When assembling the base and the electrostatic chuck, for example, the through holes formed with the sealing material are aligned with the through holes of the electrostatic chuck, and the two are joined in a state where they are held so as not to be displaced. There is also a problem that it is necessary and troublesome.

JP 2010-21510 A

  In view of the above points, the present invention does not require a surface seal for gas supply when an electrostatic chuck is bonded to a base surface to constitute a substrate holding device, and the assembly thereof is low cost. An object of the present invention is to provide a substrate holding device with an electrostatic chuck.

  In order to solve the above-mentioned problems, the substrate holding apparatus with an electrostatic chuck according to the present invention is provided with an uneven shape on an adsorption surface with an object to be adsorbed, and a first gas passage leading to the adsorption surface is formed. A dielectric having an electrode, a base supporting the dielectric, and a joining means for joining the dielectric to the base, with the adsorption surface side of the dielectric facing up, on the lower surface of the dielectric, A cylindrical body that extends downward and surrounds the open end of the first gas passage is integrally provided, and a recess is formed in the base in which the cylindrical body is fitted via a sealing means. The communicating second gas passage is formed in the base.

  According to the present invention, when assembling the dielectric and the base, for example, a vacuum seal such as an O-ring is press-fitted into a groove formed in the recess, and then the cylinder is fitted into the recess on the base. While placing the dielectric. At this time, the relative position between the dielectric and the base is positioned, and both the first and second gas passages communicate with each other through the cylinder. And a dielectric is joined with respect to a base by joining means, such as a volt | bolt. As described above, according to the present invention, since a sealing material for performing surface sealing on the joint surface between the base and the dielectric is not required, high-precision finishing is not required, and the cost can be reduced. Moreover, if the cylindrical body is fitted in the recess, the relative position between the dielectric and the base is positioned, and in the state in which the cylindrical body is fitted in the concave, no displacement occurs even when tightening a bolt or the like. Therefore, the assembly work can be facilitated.

  By the way, when an inert gas is supplied to the lower surface of the adsorbent while the adsorbent is adsorbed on the dielectric surface, if an inert gas is introduced near the center of the adsorbent, a local pressure difference occurs. It is known to be easy. For this reason, in the present invention, the cylinder is provided at the center of the lower surface of the dielectric, and the first gas passage is branched into a plurality of branches at the opening end of the first gas passage facing the cylinder. Each of the gas passages is preferably bent upward after extending in a direction perpendicular to the axis of the cylinder.

  According to this, the opening end for blowing out the inert gas can be positioned on the outer peripheral side of the adsorbent, and a configuration in which a pressure difference hardly occurs can be realized. The portion of the first gas passage that extends in the direction orthogonal to the axis of the cylinder is configured by bonding (adhering) the dielectric portions that are divided up and down, for example, Before joining, it is only necessary to form concave grooves at positions corresponding to the first gas passages on the joining surfaces, and the portion of the first gas passage in the thickness direction of the dielectric is formed by a known method. What is necessary is just to drill.

Sectional drawing explaining typically the structure of the board | substrate holding | maintenance apparatus with an electrostatic chuck of embodiment of this invention. Sectional drawing which decomposes | disassembles and demonstrates the board | substrate holding | maintenance apparatus of FIG.

  A substrate holding apparatus EC with an electrostatic chuck according to an embodiment of the present invention will be described below with reference to the drawings, taking as an example a case where an object to be attracted is a wafer W and electrostatically attracts the wafer W. In the following, terms that refer to directions such as down, left, and right are used with reference to FIG.

  1 and 2, EC is a substrate holding apparatus with an electrostatic chuck according to the present embodiment, and the substrate holding apparatus EC with an electrostatic chuck is configured to be able to raise the temperature of a wafer W to about 500 ° C. The chuck body 1 is made of a ceramic sintered body having high electrical resistance such as aluminum nitride or silicon nitride. A flange portion 11 projecting outward in the circumferential direction is formed at the lower portion of the chuck body 1, and a through hole 12 through which the bolt B can be inserted is formed in the flange portion 11. In this case, the through hole 12 is formed in a stepped shape so that the head of the bolt B is accommodated. On the upper surface, which is the suction surface of the wafer W of the chuck body 1, is concentrically erected by an annular rib portion 13 that can be brought into surface contact with the outer peripheral edge of the back surface of the wafer W and an internal space 14 surrounded by the rib portion 13. And a plurality of rod-like support portions 15.

  A pair of positive and negative electrodes 2a, 2b is embedded in the chuck body 1 via an insulating layer (not shown), and a DC voltage is applied between the electrodes 2a, 2b from a power source (not shown). . The chuck body 1 also incorporates a resistance heating type heater 3. In the center of the lower surface of the chuck body 1, a cylindrical body 4 extending downward is integrally provided. The cylinder 4 is made of a heat-resistant material such as tungsten or molybdenum, and is airtightly attached to the lower surface of the chuck body 1 by a known method such as welding. Further, a flange portion 41 extending inward in the radial direction is formed on the lower surface of the cylinder 4 so that a vacuum seal such as an O-ring comes into surface contact.

  In the chuck body 1, a first gas passage 16 that communicates with the internal space 14 on the upper surface of the chuck body 1 is provided. The first gas passage 16 has a first portion 16a extending in the vertical direction having an open end at a position surrounded by the cylindrical body 4, and an upper end of the first portion 16a so as to be spaced by 90 ° in the circumferential direction. A second portion 16b (only two of them are shown in FIG. 1) that diverges into four and extends radially outward (in FIG. 1, from the first portion in the left-right direction), and radially outward of the second portion 16b The third portion 16c is bent at the end and extends in the vertical direction. The chuck body 1 having the above-described configuration is joined to the upper surface of the base 5. The portions 16a and 16c extending in the vertical direction may be formed by a known method, and the portion 16b extending in the direction orthogonal to the axis of the cylinder 4 is divided into, for example, the chuck body 1 vertically. The portions to be formed are joined to each other, and a concave groove may be formed in the joint surface at a position corresponding to the first gas passage before joining.

  The base 5 includes a quartz plate 51 serving as a heat insulating material joined to the lower surface of the chuck body 1, and a metal support plate 52 having good thermal conductivity such as aluminum joined to the quartz plate 51. Composed. The quartz plate 51 is formed with a vertical through hole 51a through which the cylindrical body 4 is inserted and a vertical through hole 51b through which the shaft portion of the bolt B is inserted. On the other hand, a screw hole 52a into which the bolt B is screwed is formed in the support plate 52, and a concave portion 52b in which the lower surface of the cylindrical body 4 is seated is formed at the center. An annular groove 52c is formed in the flat portion of the recess 52b, and an O-ring S is press-fitted into the annular groove 52c. The support plate 52 is provided with a second gas passage 52d that communicates from the lower surface to the recess 52b. The support plate 52 is formed with a circulation path 52e through which the refrigerant can be circulated so that it can be cooled appropriately.

  In assembling the substrate holding device EC with the electrostatic chuck, the quartz plate 51 is placed on the support plate 52 with the O-ring S being press-fitted into the annular groove 52c. Next, the lower surface of the cylindrical body 4 of the chuck body 1 is seated in the recess 52b through the through hole 51a. At this time, the through holes 12, 51b and the screw holes 52a are aligned in the vertical direction. As a result, the relative position between the chuck body 1 and the base 5 is positioned, and both the first and second gas passages 16 and 52 d communicate with each other via the cylindrical body 4. And the chuck | zipper main body 1 and the base 5 are joined by installing the volt | bolt B as a joining means through each through-hole 12,51b, and screwing it in the screw hole 52a. Finally, a gas supply pipe from an inert gas source is connected to the opening end of the second gas passage 52d that opens to the lower surface of the support plate 52.

  According to the above-described embodiment, since a sealing material that performs surface sealing is not required on the joint surface between the chuck body 1 and the base 5, high-precision finishing is not required, and costs can be reduced. In addition, when the cylindrical body 4 is fitted in the recess 52b, the relative position between the chuck body 1 and the base 5 is positioned, and in the state where the cylindrical body 4 is fitted in the concave 52b, when a bolt or the like is tightened However, since the positional deviation does not occur, the assembling work can be facilitated. Further, since the first gas passage 16 is formed as described above, the opening end for blowing the inert gas can be positioned on the outer peripheral side of the wafer W, and a configuration in which a pressure difference is hardly generated can be realized.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to said thing. In the above-described embodiment, the case where the cylindrical body 4 as a separate member is integrally attached to the lower surface of the chuck body 1 by welding or the like has been described as an example. However, the present invention is not limited to this and is formed integrally with the chuck body. You can also Further, the first and second gas passages 16 and 52d communicate with each other through the inner space of the cylindrical body 4 as an example. However, another gas supply pipe is inserted into the cylindrical body 4 and the end portion thereof is connected. The first gas passage may be connected.

  In the above embodiment, the example in which the chuck body 1 and the base 5 are joined by the bolt B has been described as an example. However, the joining method is not limited to this, and other known methods may be adopted. Can do. Moreover, in the said embodiment, although what was called a bipolar type provided with a pair of positive and negative electrodes 2a and 2b was described as an example, it is not limited to this, for example, it may be a monopolar type, Furthermore, the configuration of the base 5 is not limited to the above, and for example, a quartz plate can be omitted. Furthermore, the example in which the concave and convex shape is imparted to the adsorption surface with the wafer W by the rib portion and the supporting portion has been described as an example. It doesn't matter.

EC ... electrostatic chuck, W ... wafer (substance to be attracted), 1 ... chuck body (dielectric), 2a, 2b ... electrode, 13 ... rib portion (uneven shape), 15 ... support portion (uneven shape), 16 ... 1st gas passage, 4 ... cylinder body, 5 ... base, 52b ... recessed part, 52d ... 2nd gas passage, S ... O-ring (vacuum seal).

Claims (2)

A dielectric having an irregular shape on the adsorption surface with the object to be adsorbed and having a first gas passage leading to the adsorption surface, having an electrode inside, a base supporting the dielectric, and a base And a bonding means for bonding a dielectric to
A cylindrical body is provided integrally on the lower surface of the dielectric body, and the bottom surface of the dielectric body extends around the opening end of the first gas passage and extends downward. A substrate holding device with an electrostatic chuck, wherein a concave portion to be fitted is formed in the base, and a second gas passage communicating with the cylindrical body is formed in the base. The cylinder is provided at the center of the lower surface of the dielectric, and the first gas passage is branched into a plurality at the opening end of the first gas passage facing the cylinder, and each of the branched gas passages is a cylinder. 2. The substrate holding apparatus with an electrostatic chuck according to claim 1, wherein the substrate holding apparatus is bent upward after extending in a direction perpendicular to the axis of the body.

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