Double-sided polishing machine

Abstract

To bring surface pressure distribution between an upper surface plate and a lower surface plate close to uniformity without any influence on a polishing condition due to heat.SOLUTION: A double-side polishing device 1 includes: an upper surface plate 2; a lower surface plate 3; a rotation shaft 4 for rotating the upper surface plate 2; and a shape deformation mechanism part 9 for deforming the upper surface plate 2. The shape deformation mechanism part 9 includes: a flange 10 for an upper surface plate that is connected to a lower end of the rotation shaft 4 and fixed at an upper surface of the upper surface plate 2; and a heat deformation mechanism 20 for adding heat and deforming the flange 10 for an upper surface plate.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a double-sided polishing apparatus for polishing both sides of a wafer simultaneously. [Background technology]

[0002] Typically, in the processing of disc-shaped wafers such as semiconductor wafers, double-sided polishing is performed in which the wafer is sandwiched between upper and lower platens to which polishing pads are attached, a polishing liquid (slurry) is supplied, and both sides of the wafer are polished simultaneously.

[0003] In a double-sided polishing machine for double-sided polishing, a method is known in which the shape and angle of the plates are changed during the polishing operation so that the upper and lower plates are parallel to each other. This makes the distribution of surface pressure between the upper and lower plates uniform, improving the flatness of the wafer.

[0004] Patent document 1 discloses a double-sided polishing apparatus having a shape control mechanism for changing the shape of the platen by deforming the diameter of the bottom side of the platen, the side opposite to the surface on which the polishing pad is attached. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2004-314192 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the mechanism described in Patent Document 1 uses heat to expand and contract a portion of the platen to deform it, which has the problem that this heat affects polishing conditions such as polishing heat, making it difficult to perform ideal polishing. Although control that takes this effect into account is possible, very complicated control is required.

[0007] An object of the present invention is to provide a double-sided polishing apparatus that can deform a platen without affecting the polishing conditions due to heat, and can make the surface pressure distribution between the upper and lower plates more uniform. [Means for solving the problem]

[0008] The double-sided polishing apparatus of the present invention comprises an upper platen, a lower platen, a rotating shaft for rotating the upper platen, and a shape deformation mechanism for deforming the upper platen, wherein the shape deformation mechanism has a flange for the upper platen connected to the lower end of the rotating shaft and fixed to the upper surface of the upper platen, and a thermal deformation mechanism for applying heat to the flange for the upper platen to deform it.

[0009] In the above-mentioned double-sided polishing apparatus, the thermal deformation mechanism has an annular groove formed on the upper surface of the upper platen flange about the approximately entire circumferential direction with the axis of the rotating shaft as the center axis, and a lid that covers the annular groove and is fixed to the upper platen flange to form a temperature control water channel between the annular groove and the lid, and it is desirable that the annular groove is formed at a position that satisfies the following mathematical formula, where D1 is the diameter of the upper platen and D2 is the center diameter of the annular groove. 1 / 7 < D2 / D1 < 1 / 3

[0010] In the above double-sided polishing apparatus, it is preferable that the annular groove meanders along the circumferential direction.

[0011] In the above double-sided polishing apparatus, it is preferable that the annular groove is divided.

[0012] In the above double-sided polishing apparatus, it is preferable that the thermal expansion coefficient of the metal forming the lid is different from the thermal expansion coefficient of the metal forming the upper platen flange.

[0013] In the above-mentioned double-sided polishing apparatus, the upper platen has an upper platen body and an upper platen fixing bracket that connects the upper platen body and the upper platen flange and has a hole formed in the center to form a space that is blocked by the upper platen flange, and it is desirable that the upper platen flange and the upper platen fixing bracket have a plurality of air circulation holes that take in air into the space.

[0014] In the above-mentioned double-sided polishing apparatus, it is desirable that the thermal deformation mechanism has heaters arranged on the upper and lower surfaces of the upper platen flange over almost the entire circumferential direction with the axis of the rotation shaft as the central axis, and that the heaters are formed at positions that satisfy the following mathematical formula, where D1 is the diameter of the upper platen and D3 is the central diameter of the heaters. 1 / 7 < D3 / D1 < 1 / 3

[0015] In the above-mentioned double-sided polishing apparatus, it is desirable that the upper platen has an upper platen body and an upper platen fixing bracket that connects the upper platen body and the upper platen flange, and has a plurality of through holes formed radially outward from the heater on the upper platen flange. Effect of the Invention

[0016] According to the present invention, the platen can be deformed without affecting the polishing conditions due to heat, and the distribution of surface pressure between the upper platen and the lower platen can be made more uniform. [Brief description of the drawings]

[0017] [Figure 1] 1 is an exploded perspective view of a first embodiment of a double-sided polishing apparatus according to the present invention; [Diagram 2] 1 is a cross-sectional view of a first embodiment of a double-sided polishing apparatus according to the present invention. [Diagram 3] 2 is a plan view of an upper platen flange of the double-sided polishing apparatus according to the present invention. FIG. [Figure 4] 4 is a detailed cross-sectional view of a shape deformation mechanism of the double-sided polishing apparatus according to the present invention. FIG. [Diagram 5]13 is a diagram for explaining the action of the shape deformation mechanism, showing how the outer periphery of the upper surface plate is deformed so as to lower downward. FIG. [Figure 6] 13 is a diagram for explaining the action of the shape deformation mechanism, showing how the outer periphery of the upper surface plate is deformed so as to rise upward. FIG. [Figure 7] FIG. 4 is an exploded perspective view of a second embodiment of a double-sided polishing machine according to the present invention. [Figure 8] FIG. 11 is an exploded perspective view of a third embodiment of a double-sided polishing machine according to the present invention. [Figure 9] 11 is a graph showing the relationship between the temperature of constant temperature water and the amount of deformation of an upper platen. [Figure 10] FIG. 13 is a diagram illustrating measurement positions for the deformation amount of the upper platen. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] First Embodiment Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. A double-sided polishing machine is a machine that polishes both sides of a wafer simultaneously to improve the flatness of the wafer. As shown in Figures 1 and 2, a double-sided polishing machine 1 includes an upper platen 2 and a lower platen 3 arranged vertically facing each other, a rotating shaft 4 for rotating the upper platen 2, and a rotating shaft 5 for rotating the lower platen 3. Polishing pads 23, 33 are provided on the lower surface of the upper platen 2 and the upper surface of the lower platen 3. In the following description, the circumferential direction means the circumferential direction about the axis A of the rotating shafts 4, 5 as the central axis, and the radial direction means the radial direction about the axis A of the rotating shafts 4, 5 as the central axis.

[0019] A plurality of carrier plates 6 for holding wafers W are disposed between the upper platen 2 and the lower platen 3. Holding holes 61 for holding wafers W are formed in the carrier plates 6. The carrier plates 6 are gears having an outer circumferential gear (not shown) formed therein, and mesh with a sun gear 7 and an internal gear 8 to perform planetary rotation. Note that illustration of the carrier plates 6, sun gear 7, internal gear 8, etc. is omitted in FIG. 2.

[0020] The upper surface plate 2 and the lower surface plate 3 can sandwich the wafer W held in the holding hole 61 with a desired load. The rotating shafts 4 and 5 rotate the upper surface plate 2 and the lower surface plate 3 in opposite directions. The double-sided polishing apparatus 1 performs planetary rotation of the carrier plate 6 sandwiched therebetween, and simultaneously chemically and mechanically polishes the front and back surfaces of the wafer W by pressure from the polishing pads 23, 33 and by dripping slurry (not shown).

[0021] The upper surface plate 2 of this embodiment has an upper surface plate body 21 and an upper surface plate fixing bracket 22 connected to the upper surface of the upper surface plate body 21. The rotating shaft 4 and the upper surface plate 2 are connected via an upper surface plate flange 10. Specifically, the upper surface plate flange 10 is connected to the lower end of the rotating shaft 4, and the upper surface plate flange 10 is connected to an upper surface plate fixing bracket 22 of the upper surface plate 2.

[0022] The upper platen flange 10 is made of metal and has a disk shape. The upper surface plate fixing bracket 22 is in the shape of a disk with a circular hole 22a formed in the center. The hole 22a is formed to a size that allows it to be covered by the upper surface plate flange 10. Inside the hole 22a, a space V is formed below the upper surface plate flange 10. The shape of the hole 22a is not limited to a circle, and it may be, for example, a polygonal shape. The upper surface plate flange 10 and the upper surface plate fixing bracket 22 are fixed to each other by a plurality of fixing bolts B1. The upper surface plate fixing bracket 22 and the upper surface plate main body 21 are fixed to each other by a plurality of fixing bolts B2.

[0023] The upper surface plate body 21 and the lower surface plate 3 have temperature-controlled chambers 24, 34 formed continuously in the circumferential direction. Constant-temperature water for the surface plate is supplied to the temperature-controlled chambers 24, 34 to maintain the surface plate temperature constant.

[0024] The double-sided polishing apparatus 1 is equipped with a shape deformation mechanism 9 for deforming the shape of the upper platen 2 to make the lower surface of the upper platen 2 parallel to the upper surface of the lower platen 3. The shape deformation mechanism 9 has an upper platen flange 10 and a thermal deformation mechanism 20 for applying heat to the upper platen flange 10 to cause deformation. The thermal deformation mechanism 20 of this embodiment has an annular groove 11 formed in the upper platen flange 10, and a lid 16 that covers the annular groove 11 and is fixed to the upper platen flange 10, and deforms the upper platen 2 by deforming the upper platen flange 10 with heat.

[0025] 3, the annular groove 11 is formed over approximately the entire circumference in the circumferential direction. The annular groove 11 is formed in the top surface of the upper platen flange 10. As shown in Fig. 4, the annular groove 11 of the shape deformation mechanism 9 is formed at a position close to the rotation shaft 4. Specifically, when the diameter of the upper base plate 2 is D1 (see Fig. 1) and the central diameter of the annular groove 11 is D2 (see Fig. 1), the annular groove 11 is formed at a position that satisfies the following mathematical formula (1). 1 / 7 < D2 / D1 < 1 / 3 (1)

[0026] The annular groove 11 is formed to be substantially 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, 11c. As shown in Fig. 3, 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 to be equally spaced apart in the circumferential direction. 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 so as to be equally spaced apart in the circumferential direction. The first protruding walls 12 and the second protruding walls 13 are arranged so as to be alternated in the circumferential direction.

[0027] The annular groove 11 in 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 approximately the same circumferential length. The annular groove 11 does not necessarily have to be divided, and may be formed continuously over the entire circumference in the circumferential direction. In addition, the number of divisions of the annular groove 11 is not limited to two, and may be three or more.

[0028] The upper surface plate flange 10 and the upper surface plate fixing bracket 22 have a plurality of air circulation holes 14, 15 for taking in air into the space V. The upper platen flange 10 is formed with a plurality of first air circulation holes 14 that penetrate in the axial direction and communicate the upper surface of the upper platen flange 10 with the space V. The plurality of first air circulation holes 14 are formed radially outside the annular groove 11. The plurality of first air circulation holes 14 are preferably formed at equal intervals in the circumferential direction.

[0029] 2, the upper platen fixing bracket 22 is formed with a plurality of second air circulation holes 15 that penetrate in the radial direction and communicate the side surface of the upper platen 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.

[0030] The lid 16 is formed in an annular shape when viewed in the axial direction so as to close the annular groove 11 . The lid 16 is fixed to the upper platen flange 10 by fixing bolts B3. The annular groove 11 is closed by the lid 16, thereby forming a temperature adjustment water passage 17 between the annular groove 11 and the lid 16. Since the annular groove 11 in this embodiment is divided into two, the temperature adjustment water passage 17 is divided into a first temperature adjustment water passage 171 and a second temperature adjustment water passage 172.

[0031] The double-sided polishing apparatus 1 is equipped with a water supply device (not shown) that supplies constant temperature water to the temperature adjustment water channel 17 through a water channel inlet (not shown). The water supply device has a function of heating or cooling the supplied water using a heat source such as a boiler or chiller. The water supplied from the water supply device is discharged through a water channel outlet (not shown). When water is supplied to the temperature adjustment water channel 17 by the water supply device, the water flows from one end of the temperature adjustment water channel 17 to the other end. The temperature adjustment water passage 17 has a plurality of protruding walls 12, 13 arranged alternately in the annular groove 11 that constitutes the temperature adjustment water passage 17, so that the temperature adjustment water passage 17 has a meandering shape in the circumferential direction.

[0032] The lid 16 and the upper platen flange 10 are made of metals with different thermal expansion coefficients. An alloy with a small thermal expansion coefficient, such as Invar, can be used as the metal for the lid 16. Stainless steel can be used as the metal for the upper platen flange 10. The thermal expansion coefficient of the metal forming the lid 16 in this embodiment is smaller than the thermal expansion coefficient of the metal forming the upper platen flange 10. The thermal expansion coefficient of the metal forming the lid 16 is preferably 1 / 20 to 1 / 3 of the thermal expansion coefficient of the metal forming the upper platen flange 10.

[0033] Next, the operation of the shape deformation mechanism 9 will be described. In the double-side polishing apparatus 1 of the present invention, constant temperature water is caused to flow through the temperature control water passage 17 of the shape deformation mechanism section 9, whereby the upper platen flange 10 is heated and deformed. Here, the amount of heat supplied by the constant temperature water is small relative to the volume of the upper surface plate flange 10. Therefore, when constant temperature water is flowed through the temperature control water channel 17, the temperature around the temperature control water channel 17 on the upper surface of the upper surface plate flange 10 changes, while the upper surface plate flange 10 other than the area around the temperature control water channel 17 is kept at a predetermined reference temperature by the air circulation holes 14, 15 and space V formed in the upper surface plate flange 10 and the upper surface plate fixing bracket 22. The upper surface plate flange 10 is deformed by such a temperature distribution occurring in the upper surface plate flange 10. This deformation can be adjusted by changing the thermal expansion coefficient of the lid 16. It is also possible to adjust the deformation by changing the thickness of the lid 16 and the upper surface plate flange 10 to change the structural rigidity.

[0034] For example, when constant temperature water at a temperature higher than a predetermined reference temperature (for example, reference temperature + 5°C) is passed through temperature control water channel 17, the area around temperature control water channel 17 on the upper surface of upper platen flange 10 expands more than areas other than the area around temperature control water channel 17, causing upper platen flange 10 to deform so that the outer periphery drops downward, as shown in Figure 5. Since the upper surface plate 2 in this embodiment is composed of an upper surface plate main body 21 and an upper surface plate fixing bracket 22, deformation of the upper surface plate flange 10 causes the upper surface plate fixing bracket 22 connected to the upper surface plate flange 10 to deform, and as a result, the upper surface plate main body 21 can be deformed so that the outer periphery side drops downward.

[0035] On the other hand, when constant temperature water at a temperature lower than the reference temperature (for example, reference temperature -5°C) is passed through the temperature control water channel 17, the area around the temperature control water channel 17 of the upper platen flange 10 shrinks more than areas other than the area around the temperature control water channel 17, and the upper platen flange 10 deforms so that the outer periphery rises upward, as shown in Figure 6. Deformation of the upper surface plate flange 10 causes the upper surface plate fixing bracket 22 connected to the upper surface plate flange 10 to deform, and accordingly the upper surface plate main body 21 can be deformed so that the outer periphery side rises upward.

[0036] In this embodiment, Invar, which has a small thermal expansion coefficient, is used for the lid 16, which works to reduce deformation; however, the magnitude of deformation can be adjusted by appropriately selecting a metal with an appropriate thermal expansion coefficient for the lid 16.

[0037] Next, a method of operating the double-sided polishing apparatus 1 of this embodiment will be described. The platen of the double-sided polishing apparatus 1 is manufactured so that each of its component parts meets certain dimensional tolerances. However, limitations in machining precision and the accumulation of tolerances in the components result in individual differences, which in turn results in differences in the surface pressure distribution between apparatuses. In the method of operating the double-sided polishing apparatus, the surface pressure distribution between the upper platen 2 and the lower platen 3 is grasped when the double-sided polishing apparatus 1 is introduced prior to using the apparatus to polish wafers, and then the upper platen 2 is deformed so that the surface pressure distribution becomes uniform (so that the lower surface of the upper platen 2 and the upper surface of the lower platen 3 are parallel to each other).

[0038] The method of operating the double-sided polishing machine of this embodiment includes a surface pressure distribution measuring step, a temperature setting step, and a checking and adjusting step.

[0039] 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-sided polishing apparatus 1 is introduced. 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 electrical resistance caused by 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. In the surface pressure distribution measurement process, with the polishing pads 23, 33 attached to the upper platen 2 and the lower platen 3, multiple sensor sheets are arranged at equal intervals in the circumferential direction, and the upper platen 2 is lowered until a predetermined load is reached to measure the surface pressure distribution.

[0040] The temperature setting process is a process of setting the temperature of the constant temperature water passed through the temperature adjustment water channel 17 so that the surface pressure distribution of the installed double-sided polishing apparatus 1 becomes an ideal constant surface pressure distribution. The temperature of the constant temperature water is set based on the results of a previous test. For example, the amount of deformation of the upper surface plate 2 in response to the temperature of the constant temperature water and the amount of deformation of the upper surface plate 2 per 1°C change in temperature of the constant temperature water are determined through a previous test, and the temperature of the constant temperature water is set based on the results. For example, if it is determined in the surface pressure distribution measuring step that it is better to lower the outer periphery of the upper platen 2 downward, the constant temperature water is set to a temperature that will cause the outer periphery of the upper platen 2 to lower downward.

[0041] In the water passing step, constant temperature water at the temperature set in the temperature setting step is passed through the temperature adjustment water channel 17. In the confirmation and adjustment process, after the change in shape of the upper surface plate 2 has settled, the surface pressure distribution is confirmed using a surface pressure distribution measuring device. If the surface pressure distribution is not uniform, the temperature of the constant temperature water is adjusted so that the lower surface of the upper surface plate 2 is parallel to the upper surface of the lower surface plate 3. By making the lower surface of the upper surface plate 2 and the upper surface of the lower surface plate 3 parallel, the surface pressure distribution becomes closer to uniform. When the ideal surface pressure distribution of the double-sided polishing apparatus 1 becomes constant, the confirmation and adjustment process is completed. Note that if adjustment is not possible by adjusting only the temperature of the constant temperature water, it is possible to address this by changing the thickness (rigidity) of the lid 16 or the thickness of the upper platen flange 10, but it is preferable to change the thickness of the lid 16, which has a simple shape and is inexpensive.

[0042] According to the above embodiment, by deforming the shape of the upper platen 2 using the shape deformation mechanism 9, the lower surface of the upper platen 2 and the upper surface of the lower platen 3 can be made closer to parallel, and the surface pressure distribution can be made closer to uniform. Also, by adopting a structure in which the upper platen 2 is deformed by heat by deforming the upper platen flange 10 using heat, rather than by deforming a part of the upper platen 2 using heat, the influence of heat is less likely to reach the upper platen 2. This makes it possible to make the distribution of surface pressure between the upper platen 2 and the lower platen 3 closer to uniform without affecting the polishing conditions. Furthermore, since the upper surface plate 2 is not directly deformed, deformation by a small heat source is possible, and the deformation speed following temperature changes can also be improved.

[0043] Furthermore, the thermal deformation mechanism 20 has the annular groove 11 formed in the upper platen flange 10 and the lid 16 that closes the annular groove 11, and the upper platen flange 10 and the lid 16 are made of metals with different thermal expansion coefficients, so that it is possible to adjust the amount of deformation of the upper platen flange 10. For example, the magnitude of deformation can be reduced compared to when a single metal is expanded and contracted by heat.

[0044] Furthermore, since the annular groove 11 of the thermal deformation mechanism 20 is formed in a position close to the rotating shaft 4, the amount of change at the outer circumferential position of the upper platen 2 can be made large in response to minute deformation of the upper platen flange 10. Furthermore, the protruding walls 12 and 13 are formed in the annular groove 11 and the temperature adjustment water passage 17 is meandering, so that a larger amount of heat from the constant temperature water can be transferred to the upper surface plate flange 10 .

[0045] Furthermore, if the temperature adjustment water passage 17 is long, the temperature of the constant temperature water decreases as it approaches the water passage outlet. However, by dividing the temperature adjustment water passage 17 in this embodiment into two, the temperature difference of the constant temperature water in the circumferential direction can be reduced.

[0046] In addition, by forming air circulation holes 14, 15 in the upper surface plate flange 10 and the upper surface plate fixing bracket 22, air circulates through the air circulation holes 14, 15 with the rotational movement of the upper surface plate 2, making it possible to cool the periphery of the contact portion between the upper surface plate flange 10 and the upper surface plate fixing bracket 22, and to prevent the heat of the thermal deformation mechanism 20 from being transferred to the upper surface plate main body 21. Furthermore, there is also an effect of lowering the underside temperature of the upper surface plate flange 10.

[0047] Furthermore, since the upper surface plate 2 is composed of the upper surface plate main body 21 and the upper surface plate fixing bracket 22 in which the space V is formed, it is possible to block the polishing heat transmitted from the surface side of the surface plate and the heat of the constant temperature water transmitted from the temperature control water passage 17. This makes it possible to suppress the influence of the polishing heat on the temperature control water passage 17 and the change in the amount of deformation. It is also possible to suppress the heat of the constant temperature water passed through the temperature control water passage 17 from being transmitted to the surface of the surface plate and causing a change in the polishing conditions.

[0048] In the above embodiment, the protruding walls 12, 13 are disposed in the annular groove 11. However, if the temperature distribution difference caused by the constant temperature water is sufficiently effective, it is not necessary to provide the protruding walls 12, 13.

[0049] Second Embodiment Next, a double-sided polishing apparatus 1B according to a second embodiment of the present invention will be described. The thermal deformation mechanism 20 of the double-sided polishing apparatus 1 in each of the above-described embodiments deforms the upper platen flange 10 by using the temperature distribution difference and the thermal deformation amount difference, but the present invention is not limited to this. 7, the upper platen flange 10B of the double-sided polishing apparatus 1B of this embodiment has a temperature adjustment pipe 30 attached to the upper surface of the upper platen flange 10B as a thermal deformation mechanism 20B (shape deformation mechanism 9B). The temperature adjustment pipe 30 is arranged in a spiral or concentric shape on the upper surface of the upper platen flange 10B. The thermal deformation mechanism 20B of this embodiment can supply constant temperature water to the temperature adjustment pipe 30 to deform the upper surface plate flange 10B and thereby deform the upper surface plate 2.

[0050] In the first and second embodiments, the protruding walls 12, 13 are disposed in the annular groove 11. However, if the temperature distribution difference caused by the constant temperature water is sufficiently effective, it is not necessary to provide the protruding walls 12, 13.

[0051] Third Embodiment Next, a double-sided polishing machine 1C according to a third embodiment of the present invention will be described. As shown in Figure 8, the upper platen flange 10C of the double-sided polishing apparatus 1C of this embodiment has an upper surface heater 31A attached to the upper surface of the upper platen flange 10C and a lower surface heater 31B attached to the lower surface of the upper platen flange 10C as a thermal deformation mechanism 20C (shape deformation mechanism part 9C). The heaters 31A and 31B are heating devices for heating the vicinity of the center of the upper platen flange 10C, and are, for example, film heaters that utilize metal resistance heating. The heaters 31A and 31B are disposed over approximately the entire circumference in the circumferential direction. The heaters 31A and 31B are formed at positions close to the rotation shaft 4. Specifically, the heaters 31A and 31B are formed at positions that satisfy the following formula (2), where the diameter of the upper base plate 2 is D1 and the central diameter of the heaters 31A and 31B is D3 (see FIG. 8). 1 / 7 < D3 / D1 < 1 / 3 (2) Similar to the double-sided polishing apparatuses of the first and second embodiments, the upper platen flange 10C and the upper platen fixing bracket 22 of the double-sided polishing apparatus 1C of this embodiment have a plurality of air circulation holes 14, 15. The upper platen flange 10C is formed with a plurality of first air circulation holes 14 (through holes) that penetrate in the axial direction and communicate the upper surface of the upper platen flange 10C with the space V. The first air circulation holes 14 are formed radially outside the heaters 31A and 31B. The first air circulation holes 14 are preferably formed at equal intervals in the circumferential direction.

[0052] The thermal deformation mechanism 20C of this embodiment can deform the upper surface plate flange 10C and thereby deform the upper surface plate 2 by supplying electric power to the heaters 31A and 31B.

[0053] For example, when only the upper surface heater 31A is energized, the upper surface of the upper surface flange 10C expands more than the lower surface, causing the upper surface flange 10C to deform so that the outer periphery side drops downward. The deformation of the upper surface flange 10C causes the upper surface plate fixing bracket 22 connected to the upper surface plate flange 10C to deform, and as a result, the upper surface plate main body 21 deforms so that the outer periphery side drops downward. Furthermore, when only the lower surface heater 31B is energized, the lower surface of the upper surface flange 10C expands more than the upper surface, causing the upper surface flange 10C to deform so that the outer periphery rises upward. The deformation of the upper surface flange 10C causes the upper surface plate fixing bracket 22 connected to the upper surface plate flange 10C to deform, and as a result, the upper surface plate main body 21 deforms so that the outer periphery rises upward.

[0054] Furthermore, by finely adjusting the temperatures of the heaters 31A and 31B, it is possible to adjust the amount of deformation.

[0055] According to the above embodiment, since no liquid is used for temperature adjustment, a waterproof structure or the like is not required, and the structure can be simplified. In addition, air circulation holes 14, 15 are formed in the upper platen flange 10C and the upper platen fixing bracket 22, so that air circulates through the air circulation holes 14, 15 as the upper platen 2 rotates, cooling the area around the contact point between the upper platen flange 10C and the upper platen fixing bracket 22 and preventing the heat from the heaters 31A, 31B from being transferred to the upper platen main body 21. This makes it possible to suppress changes in the polishing conditions caused by the heat from the heaters 31A and 31B being transmitted to the surface of the platen.

[0056] In the double-sided polishing apparatus 1C of the third embodiment, the space V formed below the upper platen flange 10 may be omitted, and in that case, the air circulation hole 15 may also be omitted.

[0057] In addition, in each of the above embodiments, the surface plates 2, 3 have the temperature-controlled chambers 24, 34, but if constant temperature water for the surface plates is not required, the temperature-controlled chambers 24, 34 may be omitted. EXAMPLES

[0058] An example in which the function of the shape deformation mechanism 9 of the double-sided polishing apparatus 1 of the present invention was confirmed will be described. <Example 1> In Example 1, in order to confirm the function of the shape deformation mechanism 9 of the double-sided 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 platen 2 was measured.

[0059] The deformation amount of the upper platen 2 was measured at equal intervals in the diameter direction by placing a straightness shape measuring instrument (manufactured by Hitachi Zosen Corporation) directly below the upper platen 2 with the upper platen 2 and lower platen 3 attached to the double-sided polishing apparatus 1.

[0060] Figure 9 is a graph showing the relationship between the temperature of the constant temperature water and the amount of deformation of the upper surface plate 2. The horizontal axis of the graph shown in Figure 9 is the measurement position in the diameter direction of the surface plate, and the vertical axis is the amount of deformation. The measurement positions were set on line L shown by the dashed dotted line in Figure 10, and measurements were taken at 1,000 points between outer periphery points P1 and P2 of the upper surface plate 2. The amount of deformation is plotted at intervals of 100 points on the graph in Figure 9. The amount of deformation is the vertical distance from the horizontal plane passing through the bottom end of the outermost periphery of the upper surface plate 2 to the bottom surface of the upper surface plate 2.

[0061] As can be seen from the graph in Figure 9, when constant temperature water at a predetermined reference temperature was passed through the temperature control water channel 17 of the shape deformation mechanism part 9, the maximum deformation amount measured near the center of the upper surface plate 2 was +23 μm. When constant temperature water at a predetermined reference temperature of -5°C was passed through the temperature control water channel 17 of the shape deformation mechanism 9, the maximum deformation amount measured near the center of the upper surface plate 2 was -68 µm. On the other hand, when constant temperature water at a predetermined reference temperature +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. That is, the deformation width was 179 μm / 10° C., and the deformation amount per 1° C. was 17.9 μm. The deformation amount was almost proportional to the temperature.

[0062] <Example 2> In Example 2, the surface pressure distribution between the upper platen 2 and the lower platen 3 was measured while the upper platen 2 was deformed. The above-mentioned surface pressure distribution measuring device was used for the measurement. The measurement conditions were the three conditions shown in FIG.

[0063] As a result of the measurements, when constant temperature water with a reference temperature of -5°C was passed through, the surface pressure distribution was higher on the inner circumference of the surface plate, and when constant temperature water with a reference temperature of +5°C was passed through, the surface pressure distribution was higher on the outer circumference of the surface plate, which matched the results expected from the deformation measurements. [Explanation of symbols]

[0064] 1...double-sided polishing apparatus, 2...upper plate, 3...lower plate, 4,5...rotating shaft, 6...carrier plate, 7...sun gear, 8...internal gear, 9...shape deformation mechanism, 10...flange for upper plate, 11...annular groove, 12...first protruding wall, 13...second protruding wall, 14...first air circulation hole, 15...second air circulation hole, 16...lid, 17...temperature adjustment water channel, 20...thermal deformation mechanism, 21...upper plate body, 22...upper plate fixing bracket, 23,33...polishing pad, 24,34...temperature-controlled chamber, 30...temperature adjustment pipe, 31A,31B...heater, 111...first groove, 112...second groove, V...space, W...wafer.

Claims

1. The upper surface plate and Lower surface plate and A rotation shaft that rotates the upper platen; A shape deformation mechanism that deforms the upper platen, The shape deformation mechanism includes: a flange for an upper surface plate connected to a lower end of the rotating shaft and fixed to an upper surface of the upper surface plate; and a thermal deformation mechanism for applying heat to the flange for the upper surface plate to deform the flange, The thermal deformation mechanism includes: an annular groove formed on an upper surface of the upper platen flange over substantially the entire circumference in a circumferential direction with the axis of the rotating shaft as a center axis; a lid that closes the annular groove and is fixed to the upper platen flange to form a temperature adjustment water channel between the annular groove and the lid; A double-sided polishing apparatus, wherein the annular groove is formed at a position that satisfies the following formula, where D1 is the diameter of the upper platen and D2 is the central diameter of the annular groove. 1 / 7 < D2 / D1 < 1 / 3

2. 2. The double-sided polishing apparatus according to claim 1, The annular groove snakes along the circumferential direction.

3. 3. The double-sided polishing apparatus according to claim 1, A double-sided polishing apparatus in which the annular groove is divided.

4. 4. The double-sided polishing apparatus according to claim 1, A double-sided polishing apparatus in which the thermal expansion coefficient of the metal forming the lid is different from the thermal expansion coefficient of the metal forming the upper platen flange.

5. 5. The double-sided polishing apparatus according to claim 1, The upper surface plate includes an upper surface plate body, and an upper surface plate fixing bracket that connects the upper surface plate body and the upper surface plate flange and has a hole formed in a central portion to form a space blocked by the upper surface plate flange, In a double-sided polishing apparatus, the upper platen flange and the upper platen fixing bracket have a plurality of air circulation holes for taking in air into the space.

6. An upper surface plate; Lower surface plate and A rotation shaft that rotates the upper platen; A shape deformation mechanism that deforms the upper platen, The shape deformation mechanism includes: a flange for an upper surface plate connected to a lower end of the rotating shaft and fixed to an upper surface of the upper surface plate; and a thermal deformation mechanism for applying heat to the flange for the upper surface plate to deform the flange, The upper surface plate includes an upper surface plate body, and an upper surface plate fixing bracket that connects the upper surface plate body and the upper surface plate flange and has a hole formed in a central portion to form a space blocked by the upper surface plate flange, In a double-sided polishing apparatus, the upper platen flange and the upper platen fixing bracket have a plurality of air circulation holes for taking in air into the space.

7. An upper surface plate; Lower surface plate and A rotation shaft that rotates the upper platen; A shape deformation mechanism that deforms the upper platen, The shape deformation mechanism includes: a flange for an upper surface plate connected to a lower end of the rotating shaft and fixed to an upper surface of the upper surface plate; and a thermal deformation mechanism for applying heat to the flange for the upper surface plate to deform the flange, The thermal deformation mechanism includes: a heater disposed on an upper surface and a lower surface of the upper surface plate flange over substantially the entire circumference in a circumferential direction with the axis of the rotating shaft as a central axis; A double-sided polishing apparatus, wherein the heater is disposed at a position that satisfies the following formula, where D1 is the diameter of the upper platen and D3 is the central diameter of the heater. 1 / 7 < D3 / D1 < 1 / 3

8. 8. The double-sided polishing apparatus according to claim 7, The upper surface plate has an upper surface plate body and an upper surface plate fixing bracket that connects the upper surface plate body and the upper surface plate flange, A plurality of through holes formed on the upper surface plate flange radially outward from the heater Double-sided polishing machine.

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