JP5956379B2 - Components for semiconductor manufacturing equipment - Google Patents

Description

  The present invention relates to a member for a semiconductor manufacturing apparatus.

  2. Description of the Related Art Conventionally, there are known semiconductor manufacturing apparatus members in which an electrostatic chuck having a wafer mounting surface is provided on a cooling device. As such a member for a semiconductor manufacturing apparatus, there is known a member for flowing a backside gas such as helium (He) to the back surface of a wafer for the purpose of removing heat from the wafer placed on the electrostatic chuck (for example, Patent Document 1). ).

JP 2000-315680 A

  In such a semiconductor manufacturing apparatus member, a gas supply hole that communicates a bonding surface bonded to the electrostatic chuck in the cooling device and a surface opposite to the bonding surface, and a gas supply hole in the electrostatic chuck that faces the gas supply hole. It is conceivable to include a recess formed from the surface to be mounted toward the wafer mounting surface, a pore penetrating from the bottom surface of the recess to the wafer mounting surface, and a breathable plug filled in the recess.

  However, in this member for semiconductor manufacturing equipment, when the plasma power increases, the potential difference between the cooling device and the wafer placed on the wafer placement surface increases, and dielectric breakdown occurs between the cooling device and the wafer. There was something to do. If the diameter of the recess is increased in order to prevent such dielectric breakdown, the inside of the recess is not in contact with the cooling device, so that it is not sufficiently cooled. For this reason, when the plasma power is increased, the portion of the wafer that faces the inside of the concave portion becomes locally high in temperature, and the thermal uniformity may be lowered.

  An object of the present invention is to solve these problems, and a main object of the present invention is to improve the thermal uniformity of a wafer while securing a large dielectric strength in a member for a semiconductor manufacturing apparatus.

The semiconductor manufacturing apparatus member of the present invention is
An electrostatic chuck having a wafer mounting surface is a member for a semiconductor manufacturing apparatus provided on a cooling device,
A gas supply hole that communicates a bonding surface bonded to the electrostatic chuck in the cooling device and a surface opposite to the bonding surface;
A recess formed in the electrostatic chuck from a surface facing the gas supply hole toward the wafer mounting surface, and communicating with the gas supply hole;
Penetrating from the bottom surface of the recess to the wafer mounting surface, a pore having a smaller diameter than the recess,
A breathable plug filled and bonded to the recess;
With
The recess has a step on the inner surface, the smaller diameter portion is closer to the wafer mounting surface, and the larger diameter portion is closer to the bonding surface, and the depth of the larger diameter portion is the depth of the recess. Greater than 25% and 75% or less, and the diameter of the large diameter portion is not less than 2 times and not more than 2.5 times the depth of the recess,
Is.

  According to this member for a semiconductor manufacturing apparatus, the depth of the large diameter portion provided in the recess is greater than 25% and not more than 75% of the depth of the recess, and the diameter of the large diameter portion is twice the depth of the recess. Since it is 2.5 times or less, it is possible to improve the thermal uniformity of the wafer while ensuring a large withstand voltage. Here, when the depth of the large-diameter portion is 25% or less of the depth of the recess, it is not preferable because a large withstand voltage cannot be secured. Is unfavorable because of lowering. Further, when the diameter of the large diameter portion is less than twice the depth of the recess, it is not preferable because a large withstand voltage cannot be secured, and when the diameter of the large diameter portion exceeds 2.5 times the depth of the recess. Is not preferable because the soaking property is lowered.

  In the member for a semiconductor manufacturing apparatus according to the present invention, it is preferable that the breathable plug is bonded to a step surface of the recess. The breathable plug may be bonded to the inner peripheral surface of the recess, but in that case, a portion not coated with an adhesive is likely to be formed, and the creeping breakdown voltage may be reduced. On the other hand, it is preferable because the step surface of the recess is less likely to have a portion not coated with an adhesive, and the dielectric strength of the creeping surface is improved.

  In the member for a semiconductor manufacturing apparatus according to the present invention, it is preferable that the depth of the large diameter portion is 37.5% or more and 75% or less of the depth of the recess. In this way, the effect of the present invention can be obtained more reliably.

  In the member for a semiconductor manufacturing apparatus according to the present invention, the concave portion has an intermediate diameter portion having a diameter larger than the diameter of the small diameter portion and smaller than the diameter of the large diameter portion between the small diameter portion and the large diameter portion. You may do it. Even with such a structure, the effects of the present invention can be obtained without any particular problem.

The longitudinal cross-sectional view of the member 10 for semiconductor manufacturing apparatuses of this embodiment. The A section enlarged view of FIG. The top view (part) of the member 10 for semiconductor manufacturing apparatuses. The longitudinal cross-section partial enlarged view of the member for semiconductor manufacturing apparatuses of other embodiment.

  Next, a preferred embodiment of the present invention will be described with reference to the drawings. 1 is a longitudinal sectional view of a member 10 for a semiconductor manufacturing apparatus, FIG. 2 is an enlarged view of a portion A in FIG. 1, and FIG. 3 is a plan view (part) of the member 10 for a semiconductor manufacturing apparatus.

  The semiconductor manufacturing apparatus member 10 is a member in which an electrostatic chuck 20 having a wafer mounting surface 22 is provided on a cooling device 40. A plurality of embosses (small protrusions) 23 are provided on the wafer placement surface 22, and a wafer W to be subjected to plasma processing is placed on the embosses 23.

  The cooling device 40 is a disk-shaped member made of metal such as aluminum and has a gas supply hole 42. The gas supply hole 42 communicates a bonding surface 44 bonded to the electrostatic chuck 20 in the cooling device 40 and a surface 46 opposite to the bonding surface 44.

  The electrostatic chuck 20 is a disk-shaped member made of ceramics such as alumina, and has a recess 26 and a plurality of pores 34 communicating with the recess 26. The recess 26 is formed from the position facing the gas supply hole 42 in the surface 24 opposite to the wafer mounting surface 22 toward the wafer mounting surface 22. For this reason, the recess 26 communicates with the gas supply hole 42. Further, the recess 26 is provided with a step on the inner surface, the larger diameter portion 30 being closer to the surface 24 opposite to the wafer placement surface 22 and the smaller diameter portion 32 being closer to the wafer placement surface 22. The depth of the large diameter portion 30 is greater than 25% of the depth of the recess 26 and 75% or less, preferably 37.5% or more and 75% or less. Moreover, the diameter of the large diameter part 30 is 3 times or less of the depth of the recessed part 26, Preferably it is 2 times or more and 2.5 times or less. The pore 34 has a smaller diameter than the recess 26 and penetrates from the bottom surface 27 of the recess 26 to the wafer mounting surface 22. The pores 34 are opened at locations on the wafer mounting surface 22 where the emboss 23 is not formed. The recess 26 is filled with a breathable plug 36. This breathable plug 36 is bonded via an adhesive 38 applied to the step surface 28 of the recess 26. Examples of the air-permeable plug 36 include a material obtained by finely pulverizing insulating ceramics, which is solidified with an inorganic adhesive so as to have air permeability, or a porous ceramic body. Furthermore, glass fiber, heat-resistant Teflon resin sponge, or the like may be used. Among these, a ceramic porous body is preferable because very fine air holes can be easily formed. As the adhesive 38, for example, a silicone sheet or a polyimide adhesive is used.

  The cooling device 40 and the electrostatic chuck 20 are bonded via an insulating bonding sheet 50. A through hole 52 is formed in a portion of the bonding sheet 50 that faces the gas supply hole 42.

  The semiconductor manufacturing apparatus member 10 is installed in a chamber (not shown). Then, the wafer W is mounted on the wafer mounting surface 22, the raw material gas is introduced into the chamber, and the RF voltage for generating plasma is applied to the cooling device 40, thereby generating plasma and processing the wafer W. I do. At this time, backside gas such as helium is introduced into the gas supply hole 42 from a gas cylinder (not shown). The backside gas is supplied to the space 54 on the back surface side of the wafer W through the gas supply hole 42, the air-permeable plug 36 in the recess 26, and the pore 34.

  According to the semiconductor manufacturing apparatus member 10 described above, the thermal uniformity of the wafer W can be improved while ensuring a large withstand voltage.

  It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

  For example, in the above-described embodiment, the breathable plug 36 is bonded to the step surface 28 of the recess 26 via the adhesive 38, but the inner peripheral surface of the large-diameter portion 30 is bonded via the adhesive. It may be bonded. In that case, before fitting the air-permeable plug 36 into the recess 26, an adhesive is applied to one or both of the outer peripheral surface of the air-permeable plug 36 and the inner peripheral surface of the large-diameter portion 30. The breathable plug 36 is fitted. Therefore, the adhesive between the outer peripheral surface of the air permeable plug 36 and the inner peripheral surface of the large diameter portion 30 may be partially scraped off. The portion that has been scraped off is a portion that is not coated with an adhesive, which may reduce the creeping dielectric strength. On the other hand, in the above-described embodiment, the adhesive applied to the surface of the recess 26 facing the step surface 28 of the step surface 28 and the air-permeable plug 36 is not scraped off. The part which is not made does not occur easily, and the dielectric strength of the creeping surface is improved.

  In the embodiment described above, the concave portion 26 has a structure including the large diameter portion 30 and the small diameter portion 32, but the small diameter portion 32 is interposed between the large diameter portion 30 and the small diameter portion 32 as shown in FIG. 4. It is good also as a structure provided with the medium diameter part 31 which has a diameter larger than the diameter of the large diameter part 30 larger than a diameter. In that case, the air-permeable plug 36 has a shape that matches the internal space of the recess 26 as in the above-described embodiment. The recess 26 has two step surfaces 128 and 228, and the air-permeable plug 36 is bonded to the step surfaces 128 and 228 via adhesives 138 and 238. Note that the depth and diameter of the large-diameter portion 30 may be determined in the same manner as in the above-described embodiment. Even in this case, the same effect as the above-described embodiment can be obtained.

  In the above-described embodiment, the member in which the electrostatic chuck 20 is provided on the cooling device 40 is illustrated as the semiconductor manufacturing apparatus member 10. However, a susceptor, a heater, a plate, or the like is used instead of the electrostatic chuck 20. May be.

  The member 10 for a semiconductor manufacturing apparatus described above was produced so as to have the dimensions of Examples 1 to 6 and Comparative Examples 1 to 4 shown in Tables 1 and 2. The electrostatic chuck was made of dense alumina, the cooling device was made of aluminum, and the breathable plug was made of porous alumina (porosity 35%). The pores were 0.1 mm, the thickness of the electrostatic chuck was 5 mm, and the depth of the recesses was 4 mm. The adhesive was applied to the step surface.

  With respect to Examples 1 to 6 and Comparative Examples 1 to 4, the dielectric strength voltage (kV) and the thermal uniformity were evaluated. The results are shown in Tables 1 and 2. The dielectric strength is a voltage when a DC voltage is applied between the wafer and the cooling device and an arc discharge occurs between the wafer and the cooling device, and the thermal uniformity is measured at multiple locations using a wafer with a thermocouple. This is the difference between the highest temperature and the lowest temperature. A product having an insulation withstand voltage of 5 kV or more and a soaking property of 1 ° C. or less was judged as a good product.

  In Comparative Example 1, since the creepage distance was relatively long, the withstand voltage was good. However, since the diameter of the recess was as large as 8 mm, and the cooling capacity was inferior to the other part inside the recess, the thermal uniformity deteriorated.

  In Comparative Example 2, the creepage distance was the same as in Comparative Example 1, but since the depth of the large diameter portion was too short at 1 mm, a discharge occurred through the air-permeable plug (porous alumina) during this period, and the dielectric strength voltage Worsened. Moreover, since the step was provided in the concave portion, the thermal uniformity was improved as compared with Comparative Example 1, but it exceeded 1 ° C. and was not good.

  In Comparative Example 3, the creepage distance was made longer than that of Comparative Example 1, but the depth of the large diameter portion was too short at 1 mm, so that discharge occurred through the air-permeable plug (porous alumina) during this period, and the dielectric strength voltage Worsened. Moreover, although the step was provided in the concave portion, the diameter of the large diameter portion was 14 mm, which was more than three times the depth of the concave portion (4 mm), so the heat uniformity was greatly deteriorated.

  In Examples 1 and 2, the creepage distance was the same as that of Comparative Example 1 or longer than that of Comparative Example 1, and the depth of the large diameter portion was sufficiently high at 3 mm. Moreover, since the step was provided in the concave portion and the large diameter portion was not excessively large (2 to 2.5 times the depth of the concave portion), the heat uniformity could be suppressed to less than 1 ° C.

  In Examples 3 to 5 and Comparative Example 4, the dimensions were the same as in Example 1 except for the depth of the large diameter portion. Comparative Example 2 described above also has the same dimensions as Example 1 except for the depth of the large diameter portion. Summarizing the depths of these large-diameter portions, Comparative Example 2 is 1 mm, Example 3 is 1.5 mm, Example 4 is 2 mm, Example 5 is 2.5 mm, Example 1 is 3 mm, and Comparative Example 4 is 3.5 mm. From Table 1 and Table 2, if the depth of the large diameter part exceeds 1 mm and is 3 mm or less (especially 1.5 mm or more and 3 mm or less), a non-defective product having a withstand voltage of 5 kV or more and a soaking property of 1 ° C. or less is obtained. It was. Since the depth of the concave portion is 4 mm, it can be seen that a non-defective product can be obtained if the depth of the large diameter portion is greater than 25% of the depth of the concave portion and not more than 75% (particularly not less than 37.5% and not more than 75%). It was.

  In Example 6, it was set as the same dimension as Example 1 except having provided the medium diameter part (diameter 6mm) between the large diameter part (diameter 8mm) and the small diameter part (diameter 4mm). The depth of the large diameter portion (distance from the surface opposite to the wafer mounting surface to the step surface on the large diameter portion side) is 1.5 mm, and the depth of the medium diameter portion (from the step surface on the large diameter portion side to the small diameter portion). The distance to the step surface on the side) was 1.5 mm, and the depth of the small diameter portion (distance from the step surface on the small diameter portion side to the bottom surface of the recess) was 1 mm. Also in this case, as in Example 1, a non-defective product having a dielectric breakdown voltage of 5 kV or more and a soaking property of 1 ° C. or less was obtained.

DESCRIPTION OF SYMBOLS 10 Semiconductor manufacturing apparatus member, 20 Electrostatic chuck, 22 Wafer mounting surface, 23 Embossing, 24 surface, 26 Recessed part, 27 Bottom surface, 28 Step surface, 30 Large diameter part, 31 Medium diameter part, 32 Small diameter part, 34 Thin Hole, 36 Breathable plug, 38 Adhesive, 40 Cooling device, 42 Gas supply hole, 44 Bonding surface, 46 surface, 50 Bonding sheet, 52 Through hole, 54 Space, 128,228 Step surface, 138,238 Adhesive.

Claims (4)

On a cooling device RF voltage is applied, a member for a semiconductor manufacturing device in which the electrostatic chuck is eclipsed set having a wafer mounting surface,
A gas supply hole that communicates a bonding surface bonded to the electrostatic chuck in the cooling device and a surface opposite to the bonding surface;
A recess formed in the electrostatic chuck from a surface facing the gas supply hole toward the wafer mounting surface, and communicating with the gas supply hole;
Penetrating from the bottom surface of the recess to the wafer mounting surface, a pore having a smaller diameter than the recess,
A breathable plug filled and bonded to the recess;
With
The recess has a step on the inner surface, the smaller diameter portion is closer to the wafer mounting surface, and the larger diameter portion is closer to the bonding surface, and the depth of the larger diameter portion is the depth of the recess. Greater than 25% and 75% or less, and the diameter of the large diameter portion is not less than 2 times and not more than 2.5 times the depth of the recess,
A member for semiconductor manufacturing equipment. The breathable plug is bonded to the step surface of the recess,
The member for a semiconductor manufacturing apparatus according to claim 1. The depth of the large diameter portion is 37.5% or more and 75% or less of the depth of the recess,
The member for a semiconductor manufacturing apparatus according to claim 1 or 2. The concave portion has a medium diameter portion having a diameter larger than the diameter of the small diameter portion and smaller than the diameter of the large diameter portion between the small diameter portion and the large diameter portion.
The member for semiconductor manufacturing apparatuses of any one of Claims 1-3.

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