JPH077142U - Wafer table for etching equipment - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a wafer table for an etching apparatus capable of uniformly cooling the entire wafer. [Structure] The entire etching apparatus is roughly composed of a chamber 6, a wafer table 7, an upper electrode 8 and the like. Further, the wafer table 7 has a concave portion 11b on the upper surface.
Is formed, and when the wafer 3 is placed, the gap 15
A helium gas which has a table main body 11 formed therein, a cooling water flow passage 12 penetrating laterally in the wafer table main body 11 and an opening in the concave portion 11b, and vertically penetrating the inside of the wafer table main body 11. It is composed of an introduction path 13 and a plurality of wafer retainers 14.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a wafer table for an etching apparatus suitable for cooling a wafer placed on the upper surface thereof.

[0002]

[Prior art]

 An etching apparatus in the manufacture of semiconductors is provided with a wafer cooling mechanism in order to control fluctuations in a reaction rate due to a rise in surface temperature of a wafer due to heat generated during processing. Normally, as this cooling mechanism, as shown in FIG. 2, a cooling medium passage 2 is provided in a wafer table (cathode electrode) 1, and an appropriate cooling medium composed of cooling water, low temperature liquefied gas, etc. is provided in this passage 2. The temperature of the wafer 3 placed on the wafer table 1 while being circulated is controlled.

However, in the cooling mechanism, when the adhesion of the wafer 3 mounted on the wafer table 1 to the wafer table 1 is poor, the cooling within the wafer 1 varies, which adversely affects the product. Bring For this reason, a gas introduction passage 4 having an opening 4a on the upper surface of the wafer table 1 is formed in the wafer table 1, and helium gas is ejected through the gas introduction passage 4 to above the wafer table 1 so that the wafer table 1 It has been attempted to make the cooling uniform by allowing the helium gas to stay between the wafer 1 and the wafer 3 and using helium gas as a heat transfer medium (helium chucking).

[0004]

[Problems to be solved by the device]

 However, in the case of the conventional cooling mechanism, since the etching apparatus performs the processing under vacuum, the outer edge of the wafer 3 placed on the wafer table 1 is fixed by the wafer retainer 5 and the lower surface of the wafer 3 is fixed. When the helium gas is introduced to the side, the lower surface of the wafer 3 is easily separated from the upper surface of the wafer table 1, and as shown in FIG. The wafer is most easily separated from the upper surface, and since the wafer peripheral portion 3b is constrained by the wafer retainer 5, it is in a state of being close to the upper surface of the wafer table 1 and there is an extreme difference in the thickness of the gas layer formed by helium gas. Occurs. Therefore, even if the heat transfer is performed between the wafer table 1 and the wafer 3, there is a problem in that the uniformity is poor.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a wafer table for an etching apparatus that can uniformly cool the entire wafer.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the wafer table for an etching apparatus of the present invention has a table body on which a wafer is placed on the upper surface side and is supported by the peripheral portion thereof, and the table body is cooled to indirectly attach the wafer. A wafer table for an etching apparatus, comprising: a cooling mechanism that cools the wafer efficiently; and a gas introduction passage that has an opening on the upper surface of the table body and guides a heat transfer medium gas to the upper surface of the table body. It is characterized in that the upper surface of the table is formed in a concave shape, and a gap is formed by the lower surface of the placed wafer and the upper surface of the wafer table.

[0007]

[Action]

 According to the wafer table of the etching apparatus of the present invention, when the wafer is placed on the wafer table, a gap is formed between the lower surface of the wafer and the upper surface of the wafer table. Stay in the gap to form a gas layer, and the wafer is positioned above the wafer table through the gas layer. At this time, the heat transfer medium gas flows from the opening of the gas introduction passage to the outside of the opening along the lower surface of the wafer to form a uniform gas layer on the lower surface of the wafer.

[0008]

【Example】

 Next, an embodiment of a wafer table for an etching apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an entire etching apparatus to which this wafer table is applied. Reference numeral 6 is a chamber (processing chamber), 7 is a wafer table, and 8 is an upper electrode.

The wafer table 7 has the wafer 3 mounted on the upper surface thereof and also has a function as a cathode electrode, and generates a plasma between the wafer table 7 and the upper electrode 8 which is an anode electrode to generate a reaction gas. The surface of the wafer 3 is etched by converting the active radicals into active radicals. A reaction gas introducing pipe 9 for introducing a reaction gas such as a fluoride gas into the chamber 6 is connected to the chamber 6. Further, since the etching process is performed under vacuum, a vacuum pump 10 for evacuating the inside of the chamber 6 is additionally provided.

The wafer table 7 is configured such that a wafer table main body 11 is provided with a cooling water flow passage (cooling mechanism) 12, a helium gas introduction passage (gas introduction passage) 13, and a plurality of wafer retainers 14. There is.

The wafer table main body 11 is a disk-shaped plate body having a support portion 11 a formed on the upper surface thereof and protruding upward at a height of 0.1 to 0.2 mm along the outer periphery thereof. The central portion of the wafer table body 11 surrounded by the supporting portion 11a is a concave portion 11b, and when the wafer 3 is placed on the wafer table 7, the peripheral edge of the wafer 3 is placed on the upper surface of the supporting portion 11a. The portion is supported from the lower surface side, and a gap portion 15 is formed between the concave portion 11b and the wafer 3.

The cooling water flow passage 12 has a function of cooling the wafer whose temperature rises during the etching reaction and at the same time adjusting the temperature of the wafer. The cooling water flow passage 12 is arranged so as to meander inside the wafer table main body 11 in order to make the temperature distribution of the wafer table main body 11 as uniform as possible. Cooling water is introduced into the passage from a cooling water supply source (not shown) to cool the wafer table body 11. Further, in order to adjust the temperature of the wafer described above, a flow rate control mechanism (not shown) is provided in the middle of the cooling water flow passage 12.

The helium gas introduction passage 13 is formed so as to penetrate through the wafer table body 11 in the vertical direction, and the upper end thereof is opened in the recess 11 b on the upper surface of the wafer table body 11. Then, a helium gas (heat transfer medium gas) serving as a heat transfer medium is introduced into the helium gas introduction passage 13 from a helium gas supply source (not shown) from the lower side to the upper side of the wafer table 7.

The wafer retainer 14 is formed in an inverted L-shape in cross section, and is installed at a plurality of locations along the outer periphery of the wafer 3 placed on the upper surface of the support portion 11 a of the wafer table body 11. Has been done. Each wafer retainer 14 is horizontally movable in the radial direction of the wafer table body 11.

When carrying out the etching process of the wafer in the etching apparatus having the above structure, first, the wafer 3 introduced into the chamber 6 is placed on the wafer table 7. At this time, the wafer retainer 14 is moved toward the outer periphery of the wafer table 7 and the wafer 3 is placed on the supporting portion 11a of the wafer table body 11. After that, the wafer retainer 14 of the wafer table body 11 is moved. The wafer 3 is fixed by moving it toward the center.

Next, the vacuum pump 10 is operated to bring the inside of the chamber 6 to a predetermined pressure, and then a reaction gas is introduced into the chamber 6 and plasma is generated to perform etching. Then, as the etching progresses, an exothermic reaction occurs on the surface of the wafer 3 and the temperature of the wafer 3 rises, so that the cooling mechanism of the wafer table 7 is operated. That is, cooling water is introduced into the cooling water flow passage 12 to cool the wafer table 7, and helium gas is introduced into the helium gas introduction passage 13 to cover the upper portion of the recess 11b with the wafer 3. Fill 15 with helium gas.

In this way, since the gap 15 is filled with the helium gas, the wafer 3 is transferred to the wafer table 7 through the helium gas layer having a substantially uniform thickness of 0.1 to 0.2 mm. It will be located above. Therefore, the wafer 3 whose temperature has risen is deprived of heat by the wafer table 7 through the helium gas layer, so that the temperature of the wafer 3 drops again. Then, the temperature of the wafer 3 can be adjusted by adjusting the flow rate of the cooling water to control the temperature of the wafer table 7 to an appropriate temperature.

According to the present embodiment, since the helium gas layer has a uniform thickness, every portion of the wafer 3 is equidistant from the wafer table 7, and the entire wafer 3 is made uniform. Can be cooled.

In the wafer table for the etching apparatus of the present embodiment, one helium gas introduction passage 13 is formed in the central portion of the wafer table body 11, but the number and position of the helium gas introduction passages are not limited to this. Instead, for example, a plurality of helium gas introduction passages may be provided from the central portion of the wafer table body toward the peripheral portion. Further, although the supporting portion 11a is formed on the wafer table main body 11 along the outer periphery thereof, the shape and position of the supporting portion need not be limited to this. For example, a plurality of supporting portions may be provided near the outer peripheral portion of the wafer table main body. The protrusions can also be arranged in the circumferential direction.

[0020]

[Effect of device]

 As described in detail above, according to the wafer table for an etching apparatus of the present invention, the wafer is positioned above the wafer table through the layer of the heat transfer medium gas introduced into the gap between the wafer and the wafer table. Will be done. Therefore, since the heat of the wafer is taken from a wide range on the lower surface side of the wafer through the gas layer by the wafer table cooled by the cooling mechanism, the entire wafer can be cooled uniformly.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an etching apparatus equipped with a wafer table of the present invention.

FIG. 2 is a side sectional view showing an example of a conventional wafer table for an etching apparatus.

[Explanation of symbols]

 3 Wafer 7 Wafer Table 11 Wafer Table Main Body 11a Supporting Part 11b Recess 12 Cooling Water Flow Path (Cooling Mechanism) 13 Helium Gas Introducing Path (Gas Introducing Path) 15 Gap

Claims (1)

[Scope of utility model registration request] 1. A table main body on which a wafer is placed on an upper surface side and supported by a peripheral portion thereof, a cooling mechanism for cooling the table main body to indirectly cool the wafer, and an opening portion on the upper surface of the table main body. A wafer table for an etching apparatus having a gas introduction passage for guiding a heat transfer medium gas to the upper surface side of the table body, wherein the upper surface of the wafer table is formed in a concave shape and A wafer table for an etching apparatus, wherein a gap is formed by the lower surface and the upper surface of the wafer table.