Double-sided grinding device

Abstract

A double-sided grinding device (1) is provided. The double-sided grinding device (1) comprises an upper platform (2), a lower platform (3), a rotating shaft (4) for rotating the upper platform (2), and a shape deformation mechanism (9) for deforming the upper platform (2). The shape deformation mechanism (9) comprises an upper platform flange (10) connected to the lower end of the rotating shaft (4) and fixed to the upper surface of the upper platform (2), and a thermal deformation mechanism (20) for heating the upper platform flange (10) to deform it.

Description

Technical Field

[0001] The present invention relates to a double-side polishing device for polishing both sides of a wafer simultaneously. Background Art

[0002] Generally, in the processing of disc-shaped wafers such as semiconductor wafers, double-side polishing is performed by simultaneously polishing both sides of the wafer while sandwiching the wafer between an upper platen and a lower platen to which polishing pads are attached and supplying polishing liquid (slurry).

[0003] In a double-side polishing machine, the shape and angle of the upper and lower plates are changed during the polishing operation so that the upper and lower plates are parallel to each other. This makes the surface pressure distribution of the upper and lower plates uniform, thereby improving the flatness of the wafer.

[0004] Document 1 (Japanese Patent Application Laid-Open No. 2004-314192) discloses a double-side polishing apparatus having a shape control mechanism as a mechanism for changing the shape of a platen. The shape control mechanism deforms the diameter of the bottom side of the platen opposite to the surface to which the polishing pad is attached.

[0005] However, the mechanism described in Document 1 uses heat to deform a portion of the platform by expanding and contracting, so this heat affects the polishing conditions such as polishing heat and prevents ideal polishing. Although control that takes this influence into account can be performed, it requires very complex control. Summary of the Invention

[0006] An object of the present invention is to provide a double-side polishing device that can deform a platen without affecting polishing conditions due to heat, thereby making the surface pressure distribution between the upper platen and the lower platen nearly uniform.

[0007] The double-sided polishing device of the present invention is characterized in that it comprises an upper platform, a lower platform, a rotating shaft for rotating the upper platform, and a shape deformation mechanism for deforming the upper platform, wherein the shape deformation mechanism comprises an upper platform flange connected to the lower end of the rotating shaft and fixed to the upper surface of the upper platform, and a thermal deformation mechanism for heating the upper platform flange to deform it.

[0008] In the above-mentioned double-sided grinding device, preferably, the above-mentioned thermal deformation mechanism has an annular groove and a cover, the above-mentioned annular groove is formed on the upper surface of the above-mentioned upper platform flange over approximately the entire circumference with the axis of the above-mentioned rotating shaft as the center axis, the above-mentioned cover blocks the above-mentioned annular groove and is fixed to the above-mentioned upper platform flange, and a temperature adjustment water channel is formed between the above-mentioned cover and the above-mentioned annular groove. When the diameter of the above-mentioned upper platform is set to D1 and the center diameter of the above-mentioned annular groove is set to D2, the above-mentioned annular groove is formed at a position that satisfies the following formula.

[0009] 1 / 7<D2 / D1<1 / 3.

[0010] In the double-side polishing apparatus described above, preferably, the annular groove extends in a curved manner along the circumferential direction.

[0011] In the double-side polishing apparatus described above, preferably, the annular groove is divided.

[0012] In the double-side polishing apparatus, preferably, the thermal expansion coefficient of the metal forming the cover is different from the thermal expansion coefficient of the metal forming the upper surface plate flange.

[0013] In the above-mentioned double-sided polishing device, preferably, the upper platform has an upper platform main body and an upper platform fixing bracket, the upper platform fixing bracket connects the upper platform main body and the upper platform flange, forms a hole in the central portion, and a sealed space is formed at the upper platform flange, and the upper platform flange and the upper platform fixing bracket have multiple air circulation holes for filling air into the space.

[0014] In the above-mentioned double-sided polishing device, preferably, the above-mentioned thermal deformation mechanism has a heater, and the above-mentioned heater is arranged on the upper surface and the lower surface of the flange of the above-mentioned upper platform over approximately the entire circumference with the axis of the above-mentioned rotating shaft as the center axis. When the diameter of the above-mentioned upper platform is set to D1 and the center diameter of the above-mentioned heater is set to D3, the above-mentioned heater is formed at a position that satisfies the following formula.

[0015] 1 / 7<D3 / D1<1 / 3.

[0016] In the above-mentioned double-sided polishing device, preferably, the upper platform has an upper platform body and an upper platform fixing bracket, the upper platform fixing bracket connects the upper platform body and the upper platform flange, the double-sided polishing device has a plurality of through holes, and the plurality of through holes are formed radially outward of the heater on the upper platform flange.

[0017] According to the present invention, the platen can be deformed without affecting the polishing conditions due to heat, and the surface pressure distribution between the upper platen and the lower platen can be made nearly uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is an exploded perspective view of a double-side polishing apparatus according to a first embodiment of the present invention.

[0019] Figure 2 It is a cross-sectional view of a double-side polishing apparatus according to a first embodiment of the present invention.

[0020] Figure 3 It is a top view of the flange for the upper platen of the double-side polishing apparatus of the present invention.

[0021] Figure 4 This is a detailed cross-sectional view of the shape deformation mechanism portion of the double-side polishing apparatus of the present invention.

[0022] Figure 5 This is a diagram for explaining the operation of the shape-deforming mechanism, and shows a state where the outer peripheral side of the upper platform is deformed so as to descend downward.

[0023] Figure 6 This is a diagram for explaining the function of the shape-deforming mechanism, and shows a state where the upper platform is deformed so that the outer peripheral side thereof rises upward.

[0024] Figure 7 It is an exploded perspective view of a second embodiment of the double-side polishing apparatus of the present invention.

[0025] Figure 8 It is an exploded perspective view of a third embodiment of the double-side polishing apparatus of the present invention.

[0026] Figure 9 This is a graph showing the relationship between the temperature of the constant temperature water and the deformation of the upper platform.

[0027] Figure 10 It is a diagram illustrating the measurement position of the deformation amount of the upper platform. DETAILED DESCRIPTION

[0028] [First embodiment]

[0029] Hereinafter, embodiments for implementing the present invention will be described with reference to the drawings.

[0030] Double-side polishing equipment is a device that polishes both sides of a wafer simultaneously to improve the flatness of the wafer. Figure 1 and Figure 2 As shown, the double-side polishing apparatus 1 includes an upper platen 2 and a lower platen 3 disposed vertically opposite each other, a rotation shaft 4 for rotating the upper platen 2, and a rotation shaft 5 for rotating the lower platen 3. Polishing pads 23 and 33 are provided on the lower surface of the upper platen 2 and the upper surface of the lower platen 3.

[0031] In the following description, the circumferential direction means the circumferential direction having the axis A of the rotating shafts 4 and 5 as the center axis, and the radial direction means the radial direction having the axis A of the rotating shafts 4 and 5 as the center axis.

[0032] A plurality of carrier plates 6 for holding wafers W are arranged between the upper platform 2 and the lower platform 3. The carrier plates 6 are formed with holding holes 61 for holding wafers W. The carrier plates 6 are gears formed with outer peripheral gears (not shown) and mesh with the sun gear 7 and the internal gear 8 to perform planetary rotation. Figure 2 In the figure, the carrier plate 6, the sun gear 7, the internal gear 8, etc. are omitted.

[0033] The upper surface plate 2 and the lower surface plate 3 can clamp the wafer W held in the holding hole 61 with a desired load. The rotation shafts 4 and 5 rotate the upper surface plate 2 and the lower surface plate 3 in opposite directions.

[0034] The double-side polishing apparatus 1 performs chemical mechanical polishing on both the front and back surfaces of the wafer W simultaneously by pressurizing the polishing pads 23 and 33 and dropping slurry (not shown) while planetarily rotating the carrier plate 6 held therebetween.

[0035] The upper platform 2 of this embodiment includes an upper platform body 21 and an upper platform fixing bracket 22 connected to the upper surface of the upper platform body 21 .

[0036] The rotating shaft 4 and the upper platform 2 are connected via an upper platform flange 10 . Specifically, the upper platform flange 10 is connected to the lower end of the rotating shaft 4 , and the upper platform flange 10 is connected to an upper platform fixing bracket 22 of the upper platform 2 .

[0037] The upper platform flange 10 is formed of metal and has a disk shape.

[0038] The upper platform fixing bracket 22 is in the shape of a disk with a circular hole 22a formed in the center. The hole 22a is sized to be blocked by the upper platform flange 10. A space V is formed within the hole 22a and below the upper platform flange 10. The hole 22a is not limited to a circular shape and may also be a polygonal shape, for example.

[0039] The upper platform flange 10 and the upper platform fixing bracket 22 are fixed together by a plurality of fixing bolts B1. The upper platform fixing bracket 22 and the upper platform body 21 are fixed together by a plurality of fixing bolts B2.

[0040] The upper platform body 21 and the lower platform 3 have constant temperature chambers 24 and 34 formed continuously in the circumferential direction. Constant temperature water for the platform is supplied to the constant temperature chambers 24 and 34 to maintain the platform temperature constant.

[0041] The double-side polishing apparatus 1 includes a shape deformation mechanism 9 for deforming the upper platen 2 so that the lower surface of the upper platen 2 and the upper surface of the lower platen 3 are parallel. The shape deformation mechanism 9 includes an upper platen flange 10 and a thermal deformation mechanism 20 for heating and deforming the upper platen flange 10.

[0042] The thermal deformation mechanism 20 of this embodiment includes an annular groove 11 formed in the upper platform flange 10 and a cover 16 that closes the annular groove 11 and is fixed to the upper platform flange 10 . The upper platform flange 10 is deformed by heat, thereby deforming the upper platform 2 .

[0043] like Figure 3 As shown in FIG. 1 , the annular groove 11 is formed over substantially the entire circumference. The annular groove 11 is formed on the upper surface of the upper platform flange 10 .

[0044] like Figure 4 As shown, the annular groove 11 of the shape deformation mechanism portion 9 is formed at a position close to the rotation axis 4. Specifically, if the diameter of the upper platform 2 is set to D1 (refer to Figure 2 ), the center diameter of the annular groove 11 is set to D2 (refer to Figure 2 ), it is formed at a position that satisfies the following formula (1).

[0045] 1 / 7<D2 / D1<1 / 3・・・(1).

[0046] The annular groove 11 is formed to be approximately circular when viewed from the axial direction. The annular groove 11 has a rectangular cross-section and has a bottom surface 11a and a pair of side surfaces 11b and 11c. Figure 3 As shown, a plurality of first protruding walls 12 are formed on the inner side surface 11b of the annular groove 11. The plurality of protruding walls 12 are formed at equal intervals in the circumferential direction.

[0047] Similarly, a plurality of second protruding walls 13 are formed on the outer side surface 11c of the annular groove 11. The plurality of protruding walls 13 are formed at equal intervals in the circumferential direction.

[0048] The first protruding walls 12 and the second protruding walls 13 are arranged alternately in the circumferential direction.

[0049] The annular groove 11 of this embodiment is divided into a first annular groove 111 and a second annular groove 112. The first annular groove 111 and the second annular groove 112 are formed to have substantially the same circumferential length. The annular groove 11 does not necessarily need to be divided; it can be formed continuously along the entire circumference. Furthermore, the number of divisions of the annular groove 11 is not limited to two; it can also be divided into three or more.

[0050] The upper platform flange 10 and the upper platform fixing bracket 22 have a plurality of air circulation holes 14 and 15 for introducing air into the space V.

[0051] The upper platform flange 10 is formed with a plurality of first air circulation holes 14 that extend axially through the upper platform flange 10 and connect the upper surface of the upper platform flange 10 to the space V. The plurality of first air circulation holes 14 are formed radially outward of the annular groove 11. The plurality of first air circulation holes 14 are preferably formed at equal intervals in the circumferential direction.

[0052] like Figure 2 As shown, the upper deck fixing bracket 22 is formed with a plurality of second air circulation holes 15 that penetrate in the radial direction to connect the side surface of the upper deck fixing bracket 22 with the space V. The plurality of second air circulation holes 15 are preferably formed at equal intervals in the circumferential direction.

[0053] The cover 16 is formed in an annular shape when viewed from the axial direction so as to close the annular groove 11 .

[0054] The cover 16 is fixed to the upper platform flange 10 by fixing bolts B3. The annular groove 11 is sealed by the cover 16, thereby forming a temperature-adjusting water channel 17 between the annular groove 11 and the cover 16. In this embodiment, the annular groove 11 is divided into two, so the temperature-adjusting water channel 17 is divided into a first temperature-adjusting water channel 171 and a second temperature-adjusting water channel 172.

[0055] The double-side polishing apparatus 1 includes a water supply device (not shown) that supplies constant-temperature water to the temperature-adjusting water channel 17 via a water channel inlet (not shown). The water supply device heats and cools the supplied water using a heat source such as a boiler or a cooler. The water supplied by the water supply device is discharged via a water channel outlet (not shown). The water is supplied to the temperature-adjusting water channel 17 via the water supply device, thereby flowing from one end of the temperature-adjusting water channel 17 to the other.

[0056] The plurality of protruding walls 12 and 13 are alternately arranged in the annular groove 11 constituting the temperature-adjusting water channel 17 , whereby the temperature-adjusting water channel 17 has a shape that curves with respect to the circumferential direction.

[0057] The cover 16 and the upper platform flange 10 are formed of metals having different thermal expansion coefficients. For example, an alloy with a low thermal expansion coefficient, such as Invar, can be used as the metal constituting the cover 16. For example, stainless steel can be used as the metal constituting the upper platform flange 10.

[0058] The metal forming the cover 16 of this embodiment has a smaller thermal expansion coefficient than the metal forming the upper platform flange 10. The thermal expansion coefficient of the metal forming the cover 16 is preferably 1 / 20 to 1 / 3 of that of the metal forming the upper platform flange 10.

[0059] Next, the operation of the shape-deforming mechanism 9 will be described.

[0060] In the double-side polishing apparatus 1 of the present invention, constant-temperature water flows into the temperature-adjusting water passage 17 of the shape-deforming mechanism 9 , thereby heating the upper platen flange 10 and deforming it.

[0061] Here, the amount of heat supplied to the constant-temperature water is relatively small relative to the volume of the upper platform flange 10. Therefore, when the constant-temperature water flows to the temperature-adjusting water channel 17, the temperature around the temperature-adjusting water channel 17 on the upper surface of the upper platform flange 10 changes. On the other hand, the upper platform flange 10 outside the temperature-adjusting water channel 17 is maintained at a predetermined reference temperature by means of the air circulation holes 14, 15 and the space V formed in the upper platform flange 10 and the upper platform fixing bracket 22. Due to such a temperature distribution generated in the upper platform flange 10, the upper platform flange 10 deforms. This deformation can be adjusted by changing the thermal expansion coefficient of the cover 16. In addition, the deformation can also be adjusted by changing the thickness of the cover 16 and the upper platform flange 10 and changing the structural rigidity.

[0062] For example, when constant temperature water having a temperature higher than a predetermined reference temperature (e.g., reference temperature + 5°C) is passed through the temperature adjustment water passage 17, the area around the temperature adjustment water passage 17 on the upper surface of the upper platform flange 10 expands more than the area outside the area around the temperature adjustment water passage 17. Figure 5 As shown, the upper platform flange 10 is deformed in such a manner that the outer peripheral side thereof descends downward.

[0063] The upper platform 2 of this embodiment is composed of an upper platform body 21 and an upper platform fixing bracket 22. Therefore, due to the deformation of the upper platform flange 10, the upper platform fixing bracket 22 connected to the upper platform flange 10 is deformed, and accordingly, the upper platform body 21 can be deformed in a manner that the outer peripheral side descends downward.

[0064] On the other hand, when constant temperature water at a temperature lower than the reference temperature (e.g., the reference temperature -5°C) is passed through the temperature adjustment water channel 17, the area around the temperature adjustment water channel 17 of the upper platform flange 10 shrinks compared to the area outside the area around the temperature adjustment water channel 17. Figure 6 As shown, the upper platform flange 10 is deformed in such a manner that the outer peripheral side thereof rises upward.

[0065] Due to the deformation of the upper deck flange 10 , the upper deck fixing bracket 22 connected to the upper deck flange 10 is deformed, and accordingly, the upper deck main body 21 can be deformed so that the outer peripheral side thereof rises upward.

[0066] In this embodiment, since Invar having a small thermal expansion coefficient is used for the cover 16 , deformation is reduced. However, the magnitude of deformation can be adjusted by appropriately selecting a metal having an appropriate thermal expansion coefficient as the metal for the cover 16 .

[0067] Next, a method of using the double-side polishing apparatus 1 of this embodiment will be described.

[0068] The platform of the double-side polishing device 1 is manufactured so that its structural components each meet a certain dimensional tolerance. However, due to the limit of machining accuracy and the accumulation of tolerances of structural components, individual differences occur, resulting in differences in surface pressure distribution between devices.

[0069] In the application method of the double-sided polishing device, before using the double-sided polishing device 1 to polish the wafer, the surface pressure distribution between the upper platform 2 and the lower platform 3 is grasped when the double-sided polishing device 1 is introduced, and then the upper platform 2 is deformed so that the surface pressure distribution becomes uniform (the lower surface of the upper platform 2 and the upper surface of the lower platform 3 become parallel).

[0070] The application method of the double-side polishing apparatus of this embodiment includes a surface pressure distribution measuring step, a temperature setting step, and a confirmation and adjustment step.

[0071] The surface pressure distribution measuring step is a step of measuring the surface pressure distribution between the upper platen 2 and the lower platen 3 using a surface pressure distribution measuring device when the double-side polishing apparatus 1 is introduced.

[0072] The surface pressure distribution measuring device has a sensor sheet with electrodes arranged in a grid pattern and measures the surface pressure distribution based on changes in resistance due to pressure. For example, the large-area pressure distribution measuring system BIG-MAT (manufactured by NITTA Corporation) can be used as the surface pressure distribution measuring device.

[0073] In the surface pressure distribution measurement step, with the polishing pads 23 and 33 mounted on the upper and lower plates 2 and 3 , a plurality of sensor pieces are arranged at equal intervals in the circumferential direction, and the upper plate 2 is lowered until a predetermined load is reached to measure the surface pressure distribution.

[0074] The temperature setting process involves setting the temperature of the constant-temperature water flowing into the temperature-adjusting water passage 17 so that the surface pressure distribution of the double-side polishing apparatus 1 is constant and ideal. The temperature of the constant-temperature water is set based on prior test results. For example, prior tests determine the deformation of the upper platen 2 relative to the temperature of the constant-temperature water and the deformation of the upper platen 2 per 1°C change in the constant-temperature water temperature. The constant-temperature water temperature is then set based on these results.

[0075] For example, when it is determined in the surface pressure distribution measurement step that it is better to lower the outer periphery of the upper platform 2 downward, the constant temperature water is set to a temperature that causes the outer periphery of the upper platform 2 to lower downward.

[0076] In the water flow step, the constant-temperature water having the temperature set in the temperature setting step is flowed to the temperature-adjusting water passage 17 .

[0077] During the confirmation and adjustment process, once the shape change of the upper platform 2 has stabilized, the surface pressure distribution is confirmed using a surface pressure distribution measuring device. If the surface pressure distribution is uneven, the temperature of the constant-temperature water is adjusted to make the lower surface of the upper platform 2 parallel to the upper surface of the lower platform 3. By making the lower surface of the upper platform 2 and the upper surface of the lower platform 3 parallel, the surface pressure distribution becomes nearly uniform.

[0078] The confirmation adjustment process is completed when the surface pressure distribution of the double-side polishing apparatus 1 becomes constant and ideal. Furthermore, if adjustment cannot be made simply by adjusting the temperature of the constant-temperature water, the thickness (rigidity) of the cover 16 or the thickness of the upper platform flange 10 can also be adjusted. However, it is preferable to change the thickness of the cover 16, which has a simple shape and is inexpensive.

[0079] According to the above embodiment, the shape-deforming mechanism 9 deforms the shape of the upper platform 2 , whereby the lower surface of the upper platform 2 and the upper surface of the lower platform 3 approach and become parallel to each other, and the surface pressure distribution can be made nearly uniform.

[0080] Furthermore, by adopting a structure in which the upper platen 2 is deformed by heat rather than by deforming a portion of the upper platen 2, but by deforming the upper platen flange 10 by heat, the influence of heat becomes less likely to affect the upper platen 2. Thus, the surface pressure distribution between the upper platen 2 and the lower platen 3 can be made nearly uniform without affecting the grinding conditions.

[0081] Furthermore, since the upper surface plate 2 is not directly deformed, deformation can be performed using a relatively small heat source, and the deformation speed following temperature changes can also be increased.

[0082] Furthermore, the thermal deformation mechanism 20 includes an annular groove 11 formed in the upper platform flange 10 and a cover 16 that closes the annular groove 11. The upper platform flange 10 and the cover 16 are formed of metals with different thermal expansion coefficients. This allows for adjustment of the deformation of the upper platform flange 10. For example, compared to the case where the metal alone is expanded and contracted using heat, the magnitude of the deformation can be reduced.

[0083] Furthermore, the annular groove 11 of the thermal deformation mechanism 20 is formed at a position relatively close to the rotation axis 4 , thereby increasing the amount of change in the outer peripheral position of the upper platform 2 with respect to a slight deformation of the upper platform flange 10 .

[0084] Furthermore, the protruding walls 12 and 13 are formed in the annular groove 11 , and the temperature-adjusting water channel 17 runs in a curved manner, thereby enabling more heat of the constant-temperature water to be transferred to the upper platform flange 10 .

[0085] Furthermore, as the temperature-adjusting water channel 17 becomes longer and approaches the water channel outlet, the temperature of the constant-temperature water decreases. However, the temperature-adjusting water channel 17 of this embodiment is divided into two, thereby making the temperature difference of the constant-temperature water in the circumferential direction smaller.

[0086] Furthermore, air circulation holes 14 and 15 are formed in the upper platform flange 10 and the upper platform fixing bracket 22. As the upper platform 2 rotates, air circulates through the air circulation holes 14 and 15, cooling the area around the contact portion between the upper platform flange 10 and the upper platform fixing bracket 22. This prevents heat transfer from the thermal deformation mechanism 20 to the upper platform body 21. This also has the effect of lowering the temperature of the lower surface of the upper platform flange 10.

[0087] Furthermore, the upper platform 2 is composed of an upper platform body 21 and an upper platform fixing bracket 22 defining a space V. This allows for the separation of grinding heat transferred from the platform surface from the heat of the constant-temperature water transferred from the temperature-adjusting water channel 17. This prevents the grinding heat from affecting the temperature-adjusting water channel 17 and causing changes in the amount of deformation. Furthermore, it prevents the heat from the constant-temperature water flowing through the temperature-adjusting water channel 17 from being transferred to the platform surface, thereby preventing changes in the grinding conditions.

[0088] In the above embodiment, the protruding walls 12 and 13 are arranged on the annular groove 11. However, if the temperature distribution difference due to the constant temperature water is sufficiently effective, the protruding walls 12 and 13 are not necessary.

[0089] [Second embodiment]

[0090] Next, a double-side polishing apparatus 1B according to a second embodiment of the present invention will be described.

[0091] The thermal deformation mechanism 20 of the double-side polishing apparatus 1 in each of the above-described embodiments deforms the upper platen flange 10 by utilizing the temperature distribution difference and the thermal deformation amount difference, but the present invention is not limited thereto.

[0092] like Figure 7 As shown, the upper platen flange 10B of the double-side polishing apparatus 1B of this embodiment includes a temperature adjustment tube 30 mounted on the upper surface of the upper platen flange 10B as the thermal deformation mechanism 20B (shape deformation mechanism portion 9B). The temperature adjustment tube 30 is arranged in a spiral or concentric pattern on the upper surface of the upper platen flange 10B.

[0093] The thermal deformation mechanism 20B of this embodiment can deform the upper platform flange 10B and thus the upper platform 2 by supplying constant-temperature water to the temperature adjustment pipe 30 .

[0094] Furthermore, in the first and second embodiments described above, the protruding walls 12 and 13 are arranged on the annular groove 11 . However, if the temperature distribution difference due to the constant temperature water is sufficiently effective, the protruding walls 12 and 13 are not necessary.

[0095] [Third embodiment]

[0096] Next, a double-side polishing apparatus 1C according to a third embodiment of the present invention will be described.

[0097] like Figure 8 As shown, the upper platform flange 10C of the double-sided polishing device 1C of this embodiment has an upper surface heater 31A installed on the upper surface of the upper platform flange 10C as a thermal deformation mechanism 20C (shape deformation mechanism part 9C), and a lower surface heater 31B installed on the lower surface of the upper platform flange 10C.

[0098] The heaters 31A and 31B are heating devices for heating the vicinity of the center of the upper platform flange 10C, and are, for example, film-shaped heaters that utilize resistance heating of metal. The heaters 31A and 31B are arranged over substantially the entire circumference.

[0099] The heaters 31A and 31B are formed at positions close to the rotating shaft 4. Specifically, if the diameter of the upper platform 2 is set to D1 and the center diameter of the heaters 31A and 31B is set to D3 (refer to Figure 8 ), the heaters 31A and 31B are formed at positions that satisfy the following equation (2).

[0100] 1 / 7<D3 / D1<1 / 3・・・(2).

[0101] Similar to the double-side polishing apparatuses of the first and second embodiments, the upper platen flange 10C and the upper platen fixing bracket 22 of the double-side polishing apparatus 1C of this embodiment have a plurality of air circulation holes 14 and 15 .

[0102] The upper platform flange 10C is formed with a plurality of first air circulation holes 14 (through holes) that extend axially through the upper platform flange 10C, connecting the upper surface of the upper platform flange 10C with the space V. The plurality of first air circulation holes 14 are formed radially outward of the heaters 31A and 31B. The plurality of first air circulation holes 14 are preferably formed at equal intervals in the circumferential direction.

[0103] The thermal deformation mechanism 20C of the present embodiment can deform the upper platform flange 10C and thus deform the upper platform 2 by supplying power to the heaters 31A and 31B.

[0104] For example, if only the upper surface heater 31A is energized, the upper surface of the upper platform flange 10C expands relative to the lower surface, causing the upper platform flange 10C to deform downwardly, causing the outer circumference of the upper platform flange 10C to drop downwardly. This deformation of the upper platform flange 10C also deforms the upper platform fixing bracket 22 connected to the upper platform flange 10C, thereby causing the upper platform body 21 to deform downwardly, causing the outer circumference of the upper platform flange 10C to drop downwardly.

[0105] Furthermore, if only the lower surface heater 31B is energized, the lower surface of the upper platform flange 10C expands relative to the upper surface, thereby deforming the upper platform flange 10C so that its outer circumference rises upward. This deformation of the upper platform flange 10C deforms the upper platform fixing bracket 22 connected to the upper platform flange 10C, thereby deforming the upper platform body 21 so that its outer circumference rises upward.

[0106] Furthermore, the amount of deformation can be adjusted by finely adjusting the temperature of the heaters 31A and 31B.

[0107] According to the above embodiment, since liquid is not used for temperature adjustment, a waterproof structure or the like is unnecessary, and the structure can be simplified.

[0108] In addition, air circulation holes 14 and 15 are formed at the upper platform flange 10C and the upper platform fixing bracket 22. As the upper platform 2 rotates, air circulates through the air circulation holes 14 and 15, which can cool the contact area around the upper platform flange 10C and the upper platform fixing bracket 22, and prevent heat from being transferred from the heaters 31A and 31B to the upper platform body 21.

[0109] This can suppress the heat from the heaters 31A and 31B from being transferred to the platen surface and causing the polishing conditions to change.

[0110] In the double-side polishing apparatus 1C of the third embodiment, the space V formed below the upper platen flange 10 may be omitted. In this case, the air circulation holes 15 may also be omitted.

[0111] Furthermore, in each of the above-described embodiments, the platforms 2 and 3 include the constant temperature chambers 24 and 34 . However, the constant temperature chambers 24 and 34 may be omitted unless constant temperature water for the platforms is essential. Example

[0112] An embodiment in which the function of the shape deformation mechanism 9 of the double-side polishing apparatus 1 of the present invention has been confirmed will be described.

[0113] <Example 1>

[0114] In Example 1, to confirm the function of the shape deformation mechanism 9 of the double-side polishing apparatus 1 , constant temperature water was passed through the temperature adjustment water passage 17 of the shape deformation mechanism 9 , and the deformation amount of the upper plate 2 was measured.

[0115] Regarding the deformation of the upper platen 2, a straightness shape measuring machine (manufactured by Hitachi Zosen Corporation) was set directly below the upper platen 2 while the upper platen 2 and the lower platen 3 were installed in the double-side polishing apparatus 1, and measurements were performed at equal intervals in the diameter direction.

[0116] Figure 9 Graph showing the relationship between the temperature of the constant temperature water and the deformation amount of the upper platform 2 . Figure 9 The horizontal axis of the graph shown in the figure is the measurement position in the platform diameter direction, and the vertical axis is the deformation amount. Figure 10 The measurement is performed on the straight line L indicated by the dotted line in the figure, and 1000 points are measured between the outer peripheral points P1 and P2 of the upper platform 2. Figure 9 The graph plots the deformation amount at 100-point intervals. The deformation amount is the vertical distance from a horizontal plane passing through the lower end of the outermost periphery of the upper platform 2 to the bottom surface of the upper platform 2.

[0117] according to Figure 9 As can be seen from the graph, when constant-temperature water of a predetermined reference temperature is passed through the temperature-adjusting water channel 17 of the shape-deforming mechanism 9 , the maximum deformation amount measured near the center of the upper surface plate 2 is +23 μm.

[0118] Furthermore, when constant-temperature water having a predetermined reference temperature of -5°C was passed through the temperature-adjusting water channel 17 of the shape-deforming mechanism 9 , the maximum deformation amount measured near the center of the upper surface plate 2 was -68 μm.

[0119] On the other hand, when constant temperature water of a predetermined reference temperature of +5° C. was passed through the temperature adjustment water channel 17 of the shape deformation mechanism 9 , the maximum deformation amount measured near the center of the upper surface plate 2 was +111 μm.

[0120] That is, the deformation width is 179 μm / 10° C., and the deformation amount is 17.9 μm per 1° C. The deformation amount is substantially proportional to the temperature.

[0121] <Example 2>

[0122] In Example 2, the surface pressure distribution between the upper platform 2 and the lower platform 3 was measured while the upper platform 2 was deformed. The surface pressure distribution measuring device described above was used for the measurement. Figure 9 The three conditions shown in .

[0123] The measurement results show that when constant temperature water with a reference temperature of -5°C is passed, the surface pressure distribution is high on the inner side of the platform, and when constant temperature water with a reference temperature of +5°C is passed, the surface pressure distribution is high on the outer side of the platform, which is consistent with the results assumed based on the measurement of deformation.

Claims

1. A double-sided polishing device, characterized in that: The device comprises an upper platform, a lower platform, a rotating shaft for rotating the upper platform, a shape deformation mechanism for deforming the upper platform, the shape deformation mechanism comprising an upper platform flange connected to the lower end of the rotating shaft and fixed to the upper surface of the upper platform, and a thermal deformation mechanism for deforming the upper platform flange by heating the upper platform flange. The aforementioned thermal deformation mechanism has an annular groove and a cover, The annular groove is formed on the upper surface of the upper platform flange over substantially the entire circumference of the upper surface of the upper platform flange with the axis of the rotating shaft as the central axis. The cover blocks the annular groove and is fixed to the upper platform flange, forming a temperature adjustment water channel between the cover and the annular groove. The annular groove is formed at a position satisfying the following equation when the diameter of the upper platform is set to D1 and the center diameter of the annular groove is set to D2: 1 / 7<D2 / D1<1 / 3.

2. The double-side polishing device according to claim 1, wherein: The annular groove curves along the circumferential direction.

3. The double-side polishing device according to claim 1, wherein: The annular groove is divided.

4. The double-side polishing device according to claim 1, wherein: The thermal expansion coefficient of the metal forming the cover is different from the thermal expansion coefficient of the metal forming the upper platform flange.

5. The double-side polishing device according to any one of claims 1 to 4, wherein: The upper platform comprises an upper platform body and an upper platform fixing bracket, wherein the upper platform fixing bracket connects the upper platform body and the upper platform with a flange, forms a hole in the central portion, and forms a blocked space at the upper platform flange. The upper platform flange and the upper platform fixing bracket have a plurality of air circulation holes for introducing air into the space.

6. A double-sided polishing device, characterized in that: The device comprises an upper platform, a lower platform, a rotating shaft for rotating the upper platform, a shape deformation mechanism for deforming the upper platform, the shape deformation mechanism comprising an upper platform flange connected to the lower end of the rotating shaft and fixed to the upper surface of the upper platform, and a thermal deformation mechanism for deforming the upper platform flange by heating the upper platform flange. The upper platform comprises an upper platform body and an upper platform fixing bracket, wherein the upper platform fixing bracket connects the upper platform body and the upper platform with a flange, forms a hole in the central portion, and forms a blocked space at the upper platform flange. The upper platform flange and the upper platform fixing bracket have a plurality of air circulation holes for introducing air into the space.

7. A double-sided polishing device, characterized in that: The device comprises an upper platform, a lower platform, a rotating shaft for rotating the upper platform, a shape deformation mechanism for deforming the upper platform, the shape deformation mechanism comprising an upper platform flange connected to the lower end of the rotating shaft and fixed to the upper surface of the upper platform, and a thermal deformation mechanism for deforming the upper platform flange by heating the upper platform flange. The aforementioned thermal deformation mechanism has a heater, The heater is arranged on the upper surface and the lower surface of the upper platform flange over substantially the entire circumference with the axis of the rotating shaft as the central axis. When the diameter of the upper platform is set to D1 and the center diameter of the heater is set to D3, the heater is formed at a position that satisfies the following equation: 1 / 7<D3 / D1<1 / 3.

8. The double-side polishing device according to claim 7, wherein: The upper platform comprises an upper platform body and an upper platform fixing bracket, wherein the upper platform fixing bracket connects the upper platform body and the upper platform with a flange. A plurality of through holes are provided, and the plurality of through holes are formed radially outward of the heater on the upper platform flange.

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