Components for semiconductor manufacturing equipment

Abstract

This semiconductor manufacturing device member 10 comprises a ceramic plate 20 and a cooling plate 50. The ceramic plate 20 has a circular wafer placement surface 21 including a seal band 22 along an outer circumference and has an annular focus ring placement surface 26, which is lower than the wafer placement surface 21, outside the wafer placement surface 21. Inside the ceramic plate 20, a circular inner heater electrode 30 and an annular outer heater electrode 40 provided around the inner heater electrode 30 are provided. The cooling plate 50 is provided on the opposite surface to the wafer placement surface 21 of the ceramic plate 20. The inner heater electrode 30 is provided to overlap at least a portion of the seal band 22 in a plan view, and the outer diameter of the inner heater electrode 30 is equal to or greater than 97% of the outer diameter of the wafer placement surface 21.

Description

Technical Field

[0001] The present invention relates to a member for a semiconductor manufacturing apparatus.

Background Art

[0002] Conventionally, a member for a semiconductor manufacturing apparatus that holds a wafer when manufacturing a semiconductor is known. For example, Patent Document 1 discloses a member for a semiconductor manufacturing apparatus in which a cooling plate is adhered to the lower surface of a ceramic plate. The ceramic plate has a circular wafer mounting surface provided with a seal band along the outer periphery, and has an annular stepped surface lower than the wafer mounting surface outside the wafer mounting surface. The ceramic plate has a circular inner heater electrode inside and an annular outer heater electrode provided so as to surround the inner heater electrode. Both the inner heater electrode and the outer heater electrode are provided so as not to overlap the seal band of the wafer mounting surface in plan view.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when neither the inner heater electrode nor the outer heater electrode exists directly below the seal band, there is a possibility that the temperature of the outer peripheral region of the wafer facing the seal band may decrease.

[0005] The present invention has been made to solve the above-described problems, and the main object thereof is to improve the temperature uniformity of the wafer.

Means for Solving the Problems

[0006] [1] The member for a semiconductor manufacturing apparatus of the present invention is A ceramic plate having a circular wafer placement surface provided with a seal band along the outer periphery, and having an annular focus ring placement surface lower than the wafer placement surface outside the wafer placement surface, A circular inner heater electrode provided inside the ceramic plate, An annular outer heater electrode provided inside the ceramic plate so as to surround the inner heater electrode, A cooling plate provided on the surface of the ceramic plate opposite to the wafer placement surface, and comprising, The inner heater electrode is provided so as to overlap at least a part of the seal band in plan view, and the outer diameter of the inner heater electrode is 97% or more of the outer diameter of the wafer placement surface.

[0007] In this member for a semiconductor manufacturing apparatus, the inner heater electrode is provided so as to overlap at least a part of the seal band in plan view. Also, the outer diameter of the inner heater electrode is 97% or more of the outer diameter of the wafer placement surface. Therefore, the temperature uniformity of the wafer placed on the seal band of the wafer placement surface can be improved.

[0008] [2] In the member for a semiconductor manufacturing apparatus of the present invention (the member for a semiconductor manufacturing apparatus described in [1] above), the outer diameter of the inner heater electrode may be 97% or more and 103% or less of the outer diameter of the wafer placement surface. By doing so, when viewed in plan, the inner heater electrode does not largely overlap with the focus ring placement surface. Therefore, the temperature of the focus ring is not greatly affected by the inner heater electrode, and it becomes easier to control the temperature of the focus ring with the outer heater electrode alone. 。

[0009] [3] In the member for a semiconductor manufacturing apparatus of the present invention (the member for a semiconductor manufacturing apparatus described in [1] or [2] above), the distance between the outer peripheral edge of the inner heater electrode and the inner peripheral edge of the outer heater electrode may be 2 mm or more and 18 mm or less. By doing so, the effects of the present invention can be surely obtained.

[0010] [4] In the member for a semiconductor manufacturing apparatus of the present invention (the member for a semiconductor manufacturing apparatus according to any one of [1] to [3] above), a resin adhesive layer may be provided between the ceramic plate and the cooling plate. In this case, the heat conduction from the ceramic plate to the cooling plate is restricted by the resin adhesive layer having a relatively low thermal conductivity. However, even under such circumstances, the temperature uniformity of the wafer can be enhanced.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0012] Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view of the member 10 for a semiconductor manufacturing apparatus, FIG. 2 is a plan view of the ceramic plate 20, and FIG. 3 is an explanatory drawing showing an example of the dimensions of each member.

[0013] The member 10 for a semiconductor manufacturing apparatus is a member that holds a wafer W when manufacturing a semiconductor. The member 10 for a semiconductor manufacturing apparatus includes a ceramic plate 20, a cooling plate 50, and a bonding layer 60.

[0014] The ceramic plate 20 is a ceramic disk (for example, with an outer diameter of 340 mm and a thickness of 3 mm) such as an alumina sintered body or an aluminum nitride sintered body. The ceramic plate 20 includes a circular wafer placement surface 21 and an annular focus ring placement surface 26. Hereinafter, the focus ring may be abbreviated as "FR". Inside the ceramic plate 20, an inner heater electrode 30 and an outer heater electrode 40 are embedded.

[0015] The wafer placement surface 21 is provided at the center of the ceramic plate 20. An annular seal band 22 is provided along the outer circumference of the wafer placement surface 21. As shown in FIG. 2, a seal band 22 is formed along the outer edge of the wafer placement surface 21, and a plurality of circular small protrusions 23 are formed on the entire inner surface of the seal band 22. The seal band 22 and the circular small protrusions 23 are of the same height, and the height is, for example, several μm to several tens of μm. The portion of the wafer placement surface 21 where the seal band 22 and the circular small protrusions 23 are not provided is referred to as a reference surface 24. The wafer W is placed on the top surfaces of the seal band 22 and the circular small protrusions 23. The outer diameter of the wafer W is slightly larger than the outer diameter φ1 of the wafer placement surface 21 (the same as the outer diameter of the seal band 22). Below the wafer placement surface 21 of the ceramic plate 20, an electrostatic electrode 25 is embedded. When a DC voltage is applied to the electrostatic electrode 25, the wafer W is adsorbed and fixed to the wafer placement surface 21 (specifically, the top surfaces of the seal band 22 and the circular small protrusions 23) by an electrostatic adsorption force, and when the application of the DC voltage is released, the adsorption and fixation of the wafer W to the wafer placement surface 21 is released.

[0016] The FR placement surface 26 is provided outside the wafer placement surface 21 and at a lower position than the wafer placement surface 21 (the top surface of the seal band 22). A focus ring 70 is placed on the FR placement surface 26. An upper portion of the inner peripheral surface of the focus ring 70 is provided with a stepped portion 72 along the circumferential direction. This stepped portion 72 is provided to prevent the focus ring 70 placed on the FR placement surface 26 from contacting the wafer W.

[0017] The inner heater electrode 30 is provided in a circular region that substantially coincides with the wafer placement surface 21 in a plan view. The inner heater electrode 30 is formed by wiring a resistive heating wire on a virtual plane parallel to the wafer placement surface 21 from one end to the other end without crossing each other in one stroke. The line width of the resistive heating wire is, for example, 2 mm, and the space width between adjacent resistive heating wires is, for example, 2 mm. The outer diameter φ2 of the inner heater electrode 30 (the diameter of a circle having the same center as the wafer placement surface 21 and serving as the outer peripheral edge of the inner heater electrode 30) is 97% or more of the outer diameter φ1 of the wafer placement surface 21, preferably 97% or more and 103% or less of the outer diameter φ1. The inner heater electrode 30 overlaps at least a part of the seal band 22 in a plan view.

[0018] The outer heater electrode 40 is provided in an annular region that substantially coincides with the FR placement surface 26 in a plan view. The outer heater electrode 40 is provided so as to surround the inner heater electrode 30. The outer heater electrode 40 is formed by wiring a resistive heating wire on the same plane as the inner heater electrode 30 from one end to the other end without crossing each other in one stroke. The line width of the resistive heating wire is, for example, 2 mm, and the space width between adjacent resistive heating wires is, for example, 2 mm. The outer diameter φ3 of the outer heater electrode 40 (the diameter of a circle having the same center as the wafer placement surface 21 and serving as the outer peripheral edge of the outer heater electrode 40) is slightly smaller than the outer diameter of the ceramic plate 20. The distance d between the inner peripheral edge of the outer heater electrode 40 and the outer peripheral edge of the inner heater electrode 30 is not particularly limited, but is preferably, for example, 2 to 18 mm.

[0019] The cooling plate 50 is a disk with good thermal conductivity (a disk having the same diameter as or a larger diameter than the ceramic plate 20). Inside the cooling plate 50, a refrigerant flow path 52 through which a refrigerant (for example, an electrically insulating liquid such as a fluorine-based inert liquid) circulates is provided. The refrigerant flow path 52 is formed in one stroke from the inlet to the outlet over the entire surface of the cooling plate 50 in a plan view. Examples of the material of the cooling plate 50 include metals and composite materials. Examples of the metal include Mo, Al, and Al alloys. Examples of the composite material include metal matrix composites (metal - matrix - composite (MMC)) and ceramic matrix composites (ceramic - matrix - composite (CMC)). Specific examples of such composite materials include materials containing Si, SiC, and Ti, and materials obtained by impregnating a SiC porous body with Al and / or Si. A material containing Si, SiC, and Ti is called SiSiCTi, a material obtained by impregnating a SiC porous body with Al is called AlSiC, and a material obtained by impregnating a SiC porous body with Si is called SiSiC. As the material of the cooling plate 50, it is preferable to select a material having a thermal expansion coefficient close to that of the ceramic plate 20.

[0020] The bonding layer 60 joins the lower surface of the ceramic plate 20 and the upper surface of the cooling plate 50. Examples of the bonding layer 60 include resin adhesive layers such as resin bonding sheets. The thermal conductivity of the resin adhesive layer is, for example, 0.1 to 0.3 W / mK.

[0021] Although not shown, the member 10 for a semiconductor manufacturing apparatus includes a gas supply path for supplying a heat - conductive gas (for example, He gas) from the lower surface of the cooling plate 50 to the region surrounded by the seal band 22 on the wafer placement surface 21.

[0022] Next, an example of using the member 10 for a semiconductor manufacturing apparatus will be described. The member 10 for a semiconductor manufacturing apparatus is installed in a chamber (not shown). Then, after placing the focus ring 70 on the FR placement surface 26, the wafer W is placed on the wafer placement surface 21. Subsequently, the inside of the chamber is depressurized by a vacuum pump and adjusted to a predetermined degree of vacuum, and a DC voltage is applied to the electrostatic electrode 25 to generate an electrostatic adsorption force, and the wafer W is adsorbed and fixed to the wafer placement surface 21 (specifically, the upper surface of the seal band 22 or the upper surface of the circular small protrusion 23). A refrigerant with adjusted temperature is circulated through the refrigerant flow path 52 of the cooling plate 50. The temperature of the wafer W and the temperature of the focus ring 70 are controlled by adjusting the power supplied to the inner heater electrode 30, the power supplied to the outer heater electrode 40, and the temperature of the refrigerant supplied to the refrigerant flow path. The temperature control of the wafer W is executed by detecting the temperature of the wafer W with a temperature detection sensor (not shown) and performing feedback so that the temperature becomes the target temperature. The temperature control of the focus ring is executed by detecting the temperature of the focus ring with a temperature detection sensor (not shown) and performing feedback so that the temperature becomes the target temperature. The space surrounded by the lower surface of the wafer W placed on the wafer placement surface 21 and the seal band 22 is filled with a heat conduction gas through a gas flow path (not shown). Due to the presence of this heat conduction gas, the heat conduction between the wafer W and the ceramic plate 20 is efficiently performed. And in this state, a process such as performing CVD film formation or etching on the wafer W is executed.

[0023] As the wafer W is processed, the focus ring 70 also wears out. However, since the focus ring 70 has a large thickness, the replacement of the focus ring 70 is performed after processing a plurality of wafers W.

[0024] Next, a test was conducted to examine the influence of the outer diameter φ2 of the inner heater electrode 30 on the isothermal property of the wafer W. The dimensions of each member were as shown in Fig. 3. The outer diameter φ2 was varied in the range of 273 to 321 mm. The wafer mounting surface 21 was provided with a seal band 22 but not with circular small protrusions 23. The resistance heating wire of the inner heater electrode 30 had a wire width of 2 mm and a space width of 2 mm, and the resistance heating wire of the outer heater electrode 40 also had a wire width of 2 mm and a space width of 2 mm. The thermal conductivity of the bonding layer 60 was 0.2 W / mK, the thermal conductivity of each heater electrode 30, 40 was 30 W / mK, and the thermal conductivity of the lower space of the wafer W (the space filled with He gas) was 0.05 W / mK. The wafer W and the focus ring 70 were made of silicon (thermal conductivity 163 W / mK), and the ceramic plate 20 was made of alumina (thermal conductivity 35 W / mK). Then, the power supplied to the inner heater electrode 30 and the power supplied to the outer heater electrode 40 were adjusted so that the target temperature of the wafer W became 60°C. The results of the test are shown in Figs. 4 and 5.

[0025] In the graph of Fig. 4, the horizontal axis represents the distance from the center of the wafer W, and the vertical axis represents the temperature of the wafer W. In the graph of Fig. 5, the horizontal axis represents the outer diameter φ2 of the inner heater electrode 30, and the vertical axis represents the temperature variation of the wafer W (the difference between the lowest temperature and the highest temperature between the center and the outermost periphery of the wafer W). Fig. 4 shows the results when φ2 was varied in the range of 273 to 297 mm, and Fig. 5 shows the results when φ2 was varied in the range of 273 to 321 mm.

[0026] From Figs. 4 and 5, it was found that if the outer diameter φ2 of the inner heater electrode 30 is 289 mm (97% of the outer diameter φ1 of the wafer mounting surface 21) or more, the temperature variation of the wafer W can be sufficiently suppressed. Also, it was found that if φ2 is 297 mm (100% of φ1) or more, the temperature variation of the wafer W can be further suppressed. However, if φ2 is too large, it becomes necessary to control the temperature of the focus ring 70 with both the inner heater electrode 30 and the outer heater electrode 40, so the control becomes complicated. If φ2 is suppressed to 103% or less of φ1, it becomes possible to control the temperature of the focus ring 70 with the outer heater electrode 40 alone.

[0027] Also, in FIG. 3, when φ2 was fixed at 297 mm and the distances d between the outer peripheral edge of the inner heater electrode 30 and the inner peripheral edge of the outer heater electrode 40 were set to 4 mm, 6 mm, 10 mm, and 18 mm, the temperature of the wafer W was examined. The distance d was changed by varying the inner diameter of the outer heater electrode 40. The results are shown in FIG. 6. In the graph of FIG. 6, the horizontal axis represents the distance from the center of the wafer W, and the vertical axis represents the temperature of the wafer W. In FIG. 6, the shapes of the graphs for each distance d are almost the same and overlap each other.

[0028] Furthermore, in FIG. 3, when φ2 was fixed at 297 mm, the line width of the resistance heating wire of the inner heater electrode 30 was fixed at 2 mm, the space width was fixed at 6 mm, and the distances d were set to 2 mm, 6 mm, 10 mm, and 18 mm, the temperature of the wafer W was examined. The distance d was changed by varying the inner diameter of the outer heater electrode 40. The results are shown in FIG. 7. In the graph of FIG. 7, the horizontal axis represents the distance from the center of the wafer W, and the vertical axis represents the temperature of the wafer W. In FIG. 7, the shapes of the graphs for each distance d are almost the same and overlap each other.

[0029] From FIGS. 6 and 7, it was found that the temperature variation of the wafer W can be suppressed if the distance d is in the range of 2 to 18 mm. Also, it was found that the temperature variation of the wafer W can be suppressed if the ratio L / S when the line width of the resistance heating wire of the inner heater electrode 30 is L and the space width is S is in the range of 1 / 3 to 1.

[0030] In the member 10 for a semiconductor manufacturing apparatus described above, the inner heater electrode 30 is provided so as to overlap at least a part of the seal band 22 in a plan view. Also, the outer diameter φ2 of the inner heater electrode 30 is 97% or more of the outer diameter φ1 of the wafer mounting surface 21. Therefore, the uniformity of the temperature of the wafer placed on the seal band 22 of the wafer mounting surface 21 can be enhanced.

[0031] Further, it is preferable that the outer diameter φ2 of the inner heater electrode 30 is 97% or more and 103% or less of the outer diameter φ1 of the wafer placement surface 21. By doing so, when viewed in plan, the inner heater electrode 30 does not largely overlap with the FR placement surface 26. Therefore, the temperature of the focus ring 70 is not greatly affected by the inner heater electrode 30, and it becomes easier to control the temperature of the focus ring 70 with the outer heater electrode 40 alone.

[0032] Furthermore, the distance d between the outer peripheral edge of the inner heater electrode 30 and the inner peripheral edge of the outer heater electrode 40 is preferably 2 mm or more and 18 mm or less. By doing so, the effects of the present invention can be surely obtained.

[0033] Furthermore, a resin adhesive layer may be provided as the bonding layer 60 between the ceramic plate 20 and the cooling plate 50. In this case, the heat conduction from the ceramic plate 20 to the cooling plate 50 is restricted by the resin adhesive layer having a relatively low thermal conductivity. However, even under such circumstances, the temperature uniformity of the wafer W can be enhanced.

[0034] It should be noted that the present invention is not limited to the above-described embodiments at all, 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.

[0035] In the above-described embodiments, the inner heater electrode 30 and the outer heater electrode 40 are embedded at a position 0.5 mm above the lower surface of the ceramic plate 20, but it is not particularly limited thereto. For example, this height may be appropriately set within the range of 0.5 mm or more and 2 mm The following Even in this case, the same effects as those of the above-described embodiments can be obtained.

[0036] In the above-described embodiments, the electrostatic electrode 25, the inner heater electrode 30, and the outer heater electrode 40 are embedded in the ceramic plate 20, but it is not particularly limited thereto. For example, in addition to these, an RF electrode for plasma generation may be incorporated.

[0037] In the above-described embodiment, the bonding layer 60 was exemplified by a resin adhesive layer, but it is not particularly limited thereto. For example, a metal bonding layer may be employed instead of the resin adhesive layer.

Industrial Applicability

[0038] The present invention can be used, for example, for a member for a semiconductor manufacturing apparatus that holds a wafer when manufacturing a semiconductor.

Explanation of Reference Numerals

[0039] 10 Member for semiconductor manufacturing apparatus, 20 Ceramic plate, 21 Wafer mounting surface, 22 Seal band, 23 Circular small protrusion, 24 Reference plane, 25 Electrostatic electrode, 26 Focus ring mounting surface, 30 Inner heater electrode, 40 Outer heater electrode, 50 Cooling plate, 52 Refrigerant flow path, 60 Bonding layer, 70 Focus ring, 72 Step portion, W Wafer.

Claims

1. A ceramic plate having a circular wafer placement surface provided with a seal band along its outer periphery, and having an annular focus ring placement surface lower than the wafer placement surface on the outside of the wafer placement surface; A circular inner heater electrode provided inside the ceramic plate; An annular outer heater electrode provided inside the ceramic plate so as to surround the inner heater electrode; A cooling plate provided on the surface of the ceramic plate opposite to the wafer placement surface; Comprising: The inner heater electrode is provided so as to overlap at least a part of the seal band in a plan view, and an outer diameter of the inner heater electrode is 97% or more of an outer diameter of the wafer placement surface; The inner heater electrode is formed by wiring a resistance heating wire on a single virtual plane parallel to the wafer placement surface, and the outer heater electrode is provided on the same plane as the inner heater electrode. A member for a semiconductor manufacturing apparatus.

2. A ceramic plate having a circular wafer placement surface provided with a seal band along its outer periphery, and having an annular focus ring placement surface lower than the wafer placement surface on the outside of the wafer placement surface; A circular inner heater electrode provided inside the ceramic plate; An annular outer heater electrode provided inside the ceramic plate so as to surround the inner heater electrode; A cooling plate provided on the surface of the ceramic plate opposite to the wafer placement surface; Comprising: The inner heater electrode is provided so as to overlap at least a part of the seal band in a plan view, and an outer diameter of the inner heater electrode is 100% or more of an outer diameter of the wafer placement surface. A member for a semiconductor manufacturing apparatus.

3. The outer diameter of the inner heater electrode is 97% or more and 103% or less of the outer diameter of the wafer placement surface. The member for a semiconductor manufacturing apparatus according to Claim 1.

4. A distance between an outer peripheral edge of the inner heater electrode and an inner peripheral edge of the outer heater electrode is 2 mm or more and 18 mm or less. The member for a semiconductor manufacturing apparatus according to Claim 1 or 2.

5. A resin adhesive layer is provided between the ceramic plate and the cooling plate. The member for a semiconductor manufacturing apparatus according to Claim 1 or 2.

6. The outer diameter of the inner heater electrode is 100% or more and 103% or less of the outer diameter of the wafer placement surface. The member for a semiconductor manufacturing apparatus according to Claim 2.

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