TWI389767B - Substrate grinding apparatus and substrate grinding method - Google Patents

Abstract

Provided is a substrate polishing apparatus which can smoothly polish a glass substrate for a long time. An intermediate sheet, which has a high rigidity in a tensile direction compared with that of a suction sheet, is sandwiched between a film body and the suction sheet and bonded. There are cases where the film body expands and contracts in the tensile direction due to polish resistance generated during polishing, and that peeling is generated between the intermediate sheet and the film body due to expansion and contraction of the film body. Since the intermediate sheet is arranged between the film body and the suction sheet, the intermediate sheet does not expand nor contact in the tensile direction between the suction sheet wherein expansion and contraction are limited due to suction of the glass substrate (G) and the intermediate sheet having higher rigidity in the tensile direction than that of the suction sheet. Thus, relative shift is not generated and the suction sheet is prevented from peeling and rolling up from the intermediate sheet.

Description

Substrate polishing device and substrate polishing method

The present invention relates to a substrate polishing apparatus, in particular, a substrate polishing apparatus for polishing a glass substrate to produce a thin glass substrate for a flat panel display or the like, and a substrate polishing method using the polishing apparatus.

As a method of manufacturing one of the thin-plate glass substrates for flat panel displays such as liquid crystal displays, a manufacturing method using a molding method called a float glass process is known. In the manufacturing method, the molten glass is formed into a plate shape by the above-described floating glass plate method, and then the fine irregularities or undulations on the surface of the glass plate are removed by grinding through a polishing device to obtain a thickness of 0.5 to 1.1. The thin plate-like method of mm.

The applicant of the present invention is disclosed in Patent Document 1, and a polishing apparatus for a thin-plate glass substrate for a flat panel display is proposed. The polishing apparatus is configured to supply a pressurized fluid between a membrane body to which a sorption sheet for absorbing and holding a substrate is attached, and a mounting table on which the membrane body is attached, and to pressurize the fluid The pressure is pressed against the polishing plate by the substrate sucked and held on the absorbing sheet, and is ground.

Further, the film body disclosed in Patent Document 1 is composed of an airtight holding layer, a strength holding layer, and a smoothing layer, and the absorbing sheet is formed by a porous foamed urethane sheet having its own absorbing power. .

However, in the polishing apparatus disclosed in Patent Document 1, in the substrate polishing, the absorbing sheet is peeled off from the film body and is bent up and broken to break the substrate. The problem exists. Regarding the cause of the damage of the substrate which occurred during the polishing, the applicant of the present invention found that it was caused by the following state of the art in the actual mechanical experiment.

In other words, in the polishing of the substrate, the film is subjected to a force in the drawing direction (stretching direction: surface direction) from the polishing platen due to the relationship between the polishing resistance generated between the substrate and the polishing platen. . Further, since the mounting table and the polishing platen are in the rotating state during polishing, the film body is repeatedly subjected to the stretching force in the drawing direction due to the above-described force, and is stretched and contracted in the drawing direction.

Here, the absorbing sheet which is adhered to the film body and is softer than the film body does not cause any problem if the stretching operation is performed together with the expansion and contraction of the film body. However, since the substrate is sucked and held by the absorbing sheet, that is, the stretching operation of the absorbing sheet is restricted by the substrate, the stretching of the absorbing sheet in the drawing direction is restricted. Because of this phenomenon, a relative offset occurs between the stretched film body and the non-stretchable absorbing sheet, and by this offset, the peripheral edge portion of the absorbing sheet gradually peels off from the film body. Then, when the range of the peeling becomes large, the peeled portion is bent and rolled up during the grinding. Such a problem is caused by damage to the substrate, so that it is necessary to perform maintenance.

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-122351

The present invention has been made in view of the foregoing problems, and its purpose is to provide A substrate polishing apparatus capable of polishing a substrate for a long period of time and smoothly polishing, and a substrate polishing method using the substrate polishing apparatus.

In order to achieve the above object, the present invention provides a substrate polishing apparatus which is disposed between a film body to which a suction sheet for absorbing and holding a substrate is attached, and a mounting table on which the film body is mounted. a polishing device that supplies a pressurized fluid and presses the substrate sucked by the absorbing sheet and held by the pressure to the polishing plate by the pressure of the pressurized fluid, and is ground, and is characterized in that Between the film body and the absorbing sheet, an intermediate sheet is attached, and the rigidity of the intermediate sheet in the drawing direction is higher than the rigidity of the absorbing sheet in the drawing direction.

In the present invention, an intermediate sheet is followed between the film body and the absorbing sheet. Therefore, there is a case where peeling occurs between the intermediate sheet and the film body by the stretching operation of the film body in the drawing direction corresponding to the polishing resistance, but between the intermediate sheet and the absorbing sheet, There is no relative offset. The reason for this is that since the absorbing sheet is restricted in stretching by the suction of the substrate, the rigidity of the intermediate sheet in the drawing direction is higher than that in the absorbing sheet, and stretching does not occur in the drawing direction.

As a result, the absorbing sheet will not peel off from the intermediate sheet, and the absorbing sheet can be prevented from being peeled off and bent up.

In a preferred embodiment of the present invention, the absorbing sheet can be The intermediate sheet is made of polycarbonate, acryl, aluminum, stainless steel, glass or carbon fiber reinforced plastic (CFRP: Carbon Fiber Reinforced Plastics). By manufacturing the intermediate sheet from such materials, it is possible to provide a highly rigid intermediate sheet which does not stretch in the drawing direction during substrate polishing. The intermediate sheet is more preferably made of polycarbonate.

Further, in addition to these materials, ABS (Acrylonitrile Butadiene Styrene) and Fiber Reinforced Plastics (FRP) may be exemplified.

Moreover, the present invention provides a substrate polishing method characterized in that a substrate is polished using the polishing apparatus.

According to the substrate polishing apparatus and the substrate polishing method of the present invention, the film body and the absorbing sheet are interposed between the film body and the absorbing sheet, and the film is formed to have a higher rigidity than the absorbing sheet in the drawing direction. Since the intermediate sheet does not expand and contract in the drawing direction, the intermediate sheet does not have a relative offset between the absorbing sheet and the intermediate sheet, and the absorbing sheet can be prevented from being peeled off from the intermediate sheet and bent up. Thereby, the substrate can be smoothly polished by the polishing apparatus for a long time.

Hereinafter, preferred embodiments of the substrate polishing apparatus and the substrate polishing method of the present invention will be described in detail based on the drawings.

The substrate polishing apparatus 10 shown in FIG. 1 is used to polish a single surface of a large glass substrate G (for example, one side of which is more than 2000 mm thick and has a thickness of 0.5 mm to 1.1 mm) to a glass substrate for a liquid crystal display. Flatness grinding device.

The polishing apparatus 10 is a transport apparatus 12 that transports the glass substrate G before polishing, and a stage 16 that adheres the glass substrate G to the film frame 14; and the first polishing stage 18; and the second polishing stage 20 And a platform 22 for taking out the polished glass substrate G from the film frame 14; and a glass substrate carrying and conveying device 24; and a film frame cleaning platform 26; and a film frame drying platform 28; and a film frame return conveying device 30 as a main It is composed of elements.

Further, in the polishing apparatus 10, a conveying device 150 that conveys the film frame 14 from the stage 16 to the first polishing table 18 is provided, and the film frame 14 is transferred from the first polishing table 18 to the second polishing table 20 The conveying device 152; and the conveying device 154 that conveys the film frame 14 from the second polishing table 20 to the stage 22.

The glass substrate G before polishing which is conveyed via the conveying device 12 is sucked and held by the suction pad 34 provided on the robot arm 33 of the robot 32. Then, it is transferred from the transport device 12 to the transport device 36 via the turning operation of the robot arm 33, and is transported toward the platform 16 via the transport device 36.

In the stage 16, first, the glass substrate G is held by the film frame 14. Next, a description will be given of this holding method. The film frame 14 is attached to the platform 16 and held by a lifting device (not shown) as a glass substrate bonding means. The film frame 14 is lowered by the lifting device to the glass substrate G below the film frame 14. Position, and the film body of FIG. 2 disposed on the film frame 14 38, pushing on the glass substrate G.

On the lower surface of the film body 38, a porous foamed polyurethane absorbing sheet 200 that sucks the glass substrate G itself is attached, and the intermediate sheet 210 made of polycarbonate is present. The sheet 200 and the film 38 are sucked together, and the absorbing sheet 200 and the film 38 are adhered to each other.

The glass substrate G is pressed against the absorbing sheet 200 via the pressing force from the lifting device, and is sucked and held by the absorbing sheet 200. Then, the film frame 14 is held by the conveying device 150 of Fig. 1 and conveyed to the first polishing table 18 of Fig. 3, and is attached to the mounting table 52 here.

As shown in FIG. 2, the film frame 14 is formed by attaching the film body 38 between the upper frame 40 and the lower frame 42, and then the upper frame 40 and the lower frame 42 are joined by screws (not shown). In addition, the film frame 14 or the film body 38 is not limited to a circular shape, and may be a rectangular shape.

The film body 38 is configured as a two-layer structure of the airtight holding layer 44 and the strength maintaining layer 46 as shown in FIG. As shown in FIGS. 2 and 5, the airtight holding layer 44 is sealed to the outer peripheral ring portion 53 at the lower portion of the mounting table 52, and maintains a hermetic seal between the mounting table 52 and the air chamber 54. material. Examples of the material of the sealing material include ethylene, nylon, and urethane such as rubber, hydrazine, fluorocarbon resin, and polyvinyl chloride (PVC). Further, the strength holding layer 46 of Fig. 4 is a sealing material having a specific tensile strength capable of withstanding the tension when the entire film body 38 is placed, while maintaining the airtight holding layer 44. Further, below it, there is an intermediate sheet 210. As the adhesive, an adhesive used in the film body of the prior art can be suitably used. For example, a polyurethane-based adhesive can be used, or Epoxy based adhesive.

As the material of the strength maintaining layer 46, guanamine fiber, stainless steel gold mesh, steel mesh, carbon fiber, glass fiber, nylon fiber, metal foil, resin sheet, or the like can be used, and the guanamine fiber is pulled by the tension. The amount of stretch is extremely small, so it is ideal.

Next, the polishing head 50 shown in FIG. 3 will be described. However, since the polishing head 50 of the first polishing table 18 and the polishing head 50 of the second polishing table 20 have the same structure, the same symbols are attached. Description.

In the polishing head 50, a motor is housed in the main body casing 51, and the output shaft of the motor is coupled to a rotating shaft 56 that is suspended in the vertical direction. The mounting shaft 52 is coupled to the rotating shaft 56. Further, the main body casing 51 is coupled to the slider 158 via the elevating mechanism 156. By moving the main body casing 51 relative to the slider 158 by the lifting mechanism 156, the mounting table 52 advances and retreats with respect to the polishing pad 58 of the first polishing table 18 and the polishing pad 60 of the second polishing table 20. At the same time as the movement, the glass substrate G attached to the film frame 14 can be pressed against the polishing pads 58, 60 at a specific polishing pressure.

The polishing pad 58 is attached to the upper surface of the polishing platen 62, and a rotary shaft 64 that is rotated by a motor (not shown) is connected to the lower portion of the polishing platen 62. Further, the polishing pad 60 is attached to the upper surface of the polishing table 66, and a rotary shaft 68 that is rotated by a motor (not shown) is connected to the lower portion of the polishing plate 66.

Further, the main body casing 51 is connected to a revolving drive mechanism (not shown), and has a function of revolving with a specific revolution radius. In addition, the revolving drive mechanism has a planetary gear mechanism incorporated in the main body casing 51, and It is also possible to connect the output shaft of the planetary gear mechanism to the rotating shaft 56. The above is the configuration of each of the polishing stages 18 and 20, and the glass substrate G is polished by the polishing stages 18 and 20 to remove minute irregularities or ridges on the surface of the glass substrate G.

On the other hand, the linear motion guide members 70 and 70 are attached to the slider 158 of the first polishing mechanism 18. The linear motion guiding members 70, 70 are fitted to the guide rails 72, 72. The guide rails 72, 72 are disposed toward the rotating shaft 56 of the first polishing table 18 or the maintenance platform 74 of the maintenance mounting table 52, as shown in FIG.

Further, as shown in FIG. 2, in the slider 158 of the second polishing table 20, the linear motion guiding members 70 and 70 are also attached, and the linear motion guiding members 70 and 70 are fitted to the guide rail 160. 160. The guide rails 160 and 160 are disposed toward the rotating shaft 56 of the second polishing table 20 or the maintenance platform 76 of the maintenance mounting table 52 as shown in FIG. 1 .

As shown in FIG. 2, the mounting table 52 is fixed to the outer peripheral portion of the upper portion of the mounting table 52 by a screw (not shown). In the flange portion of the hanging ring 78 that protrudes from the outer peripheral portion of the mounting table 52, a plurality of through holes 80, 80, ... are formed at equal intervals on the concentric circles, and the through holes 80, 80, ... The slide ring spreader 84 that is protruded from the upper side of the slide ring 82 penetrates from below as shown in FIG. Further, the slide ring spreader 84 passes through the hanging spring 88 disposed between the hanging ring 78 and the hanging disc spring 86, and penetrates through the through hole 90 of the hanging disc spring 86 to be connected to Spiral jack 92.

Therefore, if the screw jack 92 is operated, the slip ring spreader 84 and the suspension When the pushing force of the upper spring 88 is pulled upward, the sliding ring 82 is pulled up with respect to the mounting table 52. Thereby, the film frame 14 attached to the slide ring 82 is detached, and the film body 38 is given a specific tension.

When the tension is applied by automation, a plurality of film frames 14 and a film body 38 are prepared for use. However, considering the film frame 14, there is an individual difference in the initial tension of the film body 38, and the initial tension of the plurality of film bodies 38, 38... is different due to the difference in the use time, for all individuals having tension It is difficult for the different film body 38 to impart the same tension system. Further, if excessive tension is applied to the film body 38, there is a risk of damage to the film body 38 or peripheral equipment. In order to solve this problem, the amount of contraction of the hanging spring 88 (the distance between the hanging ring 78 and the hanging disc spring 86) is monitored. That is, not only the amount of pulling of the screw jack 92 but also the tension applied to the film body 38 is actually measured to monitor the amount of contraction of the hanging spring 88. By providing the suspension spring 88, it is possible to simultaneously solve the problem of applying a certain tension to the film body 38 and prevent excessive tension from being applied to the film body 38. Further, in order to apply a constant tension, it is necessary to measure the amount of contraction of the suspension spring 88. However, as one of the means, the screw jack 92 can be connected to a motor (not shown) connected via the linear shaft 96. The current value is used to calculate the torque, and the lifting force of the screw jack 92 is indirectly obtained and managed, and the tension imparted to the film body 38 can be monitored. The linear shaft 96 is a shaft that transmits the driving force of the motor to the screw jack 92. Further, reference numeral 94 is a stopper pin for receiving the reaction force of the hanging spring 88 generated between the hanging ring 78 and the hanging disc spring 86.

The mounting table 52 is formed with a plurality of compressed air chambers 54 from FIG. The injection ports 98, 98, ... which are ejected by air (pressurized fluid). The injection ports 98, 98, . . . are in communication with the air supply path 102 indicated by a broken line in FIG. 3 via the air chamber 100 formed on the upper surface of the mounting table 52. The air supply path 102 is extended outside the polishing head 50 via a rotary joint (not shown) attached to the polishing head 50, and is connected to the air pump 106 via the valve 104. Therefore, when the valve 104 is opened, the compressed air from the air pump 106 is supplied to the air chamber 54 via the air supply path 102, the air chamber 100, and the injection port 98. Thereby, the pressure of the compressed air is transmitted to the glass substrate G via the film body 38, and the substrate G is pressed against the polishing heads 58, 60 and polished by the pressure.

On the other hand, as shown in FIG. 2, in the frame 40 above the film frame 14, a plurality of pins 108, 108 are provided on the concentric circles at equal intervals, and at the upper ends of the pins 108, The thick-diameter head portion 110 shown in Fig. 5 is attached to the slide ring 82 by fitting with a hook 112 fixed to the lower portion of the slide ring 82. The fitting force of the head portion 110 and the hook 112 is further enhanced by the reaction force of the film body 38 when the film body 38 is stretched by the screw jack 92, and the light is subjected to the polishing resistance from the film body 38 during polishing. The head 110 is not disengaged from the hook 112.

When the polishing of the glass substrate G is completed in the second polishing table 20 shown in FIG. 1, the film frame 14 is removed from the mounting table 52 and transported to the stage 22 by the transfer device 154. As a method of removing the film frame 14 from the mounting table 52, first, the screw jack 92 shown in Fig. 5 is moved in a loose direction, and the tension of the film body 38 is released. Next, the film frame 14 is rotated by a specific angle with respect to the mounting table 52, and the head 110 is removed from the hook 112. By this, The film frame 14 is removed from the mounting table 52.

On the stage 22 shown in FIG. 1, the glass substrate G which finished polishing is peeled off from the film frame 14 conveyed by the conveyance apparatus 154. The peeled glass substrate G is transported via the transport device 138, and then sucked onto the suction head 144 attached to the robot arm 142 of the robot 140, and transferred to the glass substrate by the operation of the robot 140. The conveying device 24 is used to carry out the outside of the polishing device 10.

The film frame 14 after the glass substrate G is peeled off is conveyed to the film frame cleaning stage 26 via the conveyance device 146, and is washed with water here. The film frame 14 that has been cleaned is conveyed to the film frame drying stage 28 via the conveying device 148, and is heated and dried there. Then, the dried film frame 14 is conveyed back to the conveyance device 30 via the film frame, and is conveyed to the stage 16, and is used again for the adhesion of the glass substrate G. The above is the overall configuration of the polishing apparatus 10.

The film body 38 is subjected to the polishing resistance generated between the glass substrate G and the polishing pads 58 and 60 during polishing of the glass substrate G, and thus is received from the polishing pads 58 and 60 toward the drawing direction ( Stretching direction: the direction of the face). Further, since the mounting table 52 and the polishing heads 58 and 60 are rotated in the polishing state, the film body 38 is repeatedly subjected to the stretching force in the pulling direction due to the above-described force, and expands and contracts in the drawing direction.

Here, in the prior structure, since the absorbing sheet 200 which is softer than the film body 38 is directly attached to the film body 38, if the behavior of the absorbing sheet 200 during polishing is observed, it can be found that if it is sucked If the sheet 200 follows the contraction of the film 38 to perform the expansion and contraction operation, there is no problem, but Since the absorbing sheet 200 is held on the glass substrate G, that is, since the stretching operation of the absorbing sheet 200 is restricted by the glass substrate G, the expansion and contraction of the absorbing sheet 200 in the drawing direction is restricted. . Because of this phenomenon, a relative offset is generated between the stretched film body 38 and the non-stretchable absorbing sheet 200, and by this offset, the peripheral edge portion of the absorbing sheet 200 is from the film body 38. Gradually peeling off, when the peeling portion becomes large, the peeled portion is bent and rolled up during the grinding.

Here, in order to prevent such a problem, in the structure of the embodiment, as shown in FIG. 6, the intermediate sheet 210 having a higher rigidity in the drawing direction than the absorbing substrate 200 is present in the film. The body 38 and the absorbing sheet 200 are then passed.

According to this configuration, the film body 38 expands and contracts in the drawing direction as described above due to the polishing resistance occurring during polishing, but there is an intermediate sheet between the film body 38 and the absorbing sheet 200. 210, therefore, there is a case where peeling occurs between the intermediate sheet 210 and the film body 38 due to the expansion and contraction operation of the film body 38, but between the intermediate sheet 210 and the absorbing sheet 200, by the suction of the glass substrate G The absorbing sheet 200 whose telescopic movement is restricted, and the intermediate sheet 210 which is higher in rigidity in the drawing direction than the absorbing sheet 200, does not expand and contract in the drawing direction, and therefore does not Produces a relative offset. Therefore, since the absorbing sheet 200 will not peel off from the intermediate sheet 210, the absorbing sheet 200 can be prevented from being peeled off and bent up.

Therefore, according to the polishing apparatus 10 of the embodiment, the glass substrate G can be smoothly polished for a long period of time.

Further, in the embodiment, polycarbonate is used as the material of the intermediate sheet 210. However, the present invention is not limited thereto, and acryl, aluminum, stainless steel, glass, or carbon fiber reinforced plastic may be used. Further, in addition to these materials, ABS (Acrylonitrile Butadiene Styrene) and Fiber Reinforced Plastics (FRP) may be exemplified.

Further, since the film body 38 is formed by the airtight holding layer 44 and the strength maintaining layer 46, and the intermediate sheet 210 is attached to the strength protective layer 46, the smooth layer following the strength maintaining layer 46 can be removed. The cost of the film body 38 can be reduced.

[Industry use possibility]

The present invention is suitable for polishing a glass substrate used for a thin glass substrate used in a flat panel display or the like.

In addition, the contents of the specification, the scope of the application, the drawings and the abstract of the Japanese Patent Application No. 2005-239040, filed on Jan. 19, 2005, are hereby incorporated by reference.

G‧‧‧glass substrate

10‧‧‧ grinding device

12‧‧‧Conveyor

14‧‧‧ film frame

16‧‧‧ platform

18‧‧‧1st grinding platform

20‧‧‧2nd grinding platform

22‧‧‧ platform

24‧‧‧Glass substrate carrying out conveyor

26‧‧‧Film frame cleaning platform

28‧‧‧Film frame drying platform

30‧‧‧film frame return conveyor

32‧‧‧ Robot

33‧‧‧ robot arm

34‧‧‧Sucking gasket

36‧‧‧Conveyor

38‧‧‧membrane body

40‧‧‧上上

42‧‧‧ Lower frame

44‧‧‧ airtight retaining layer

46‧‧‧Strength retention layer

48‧‧‧Smooth layer

50‧‧‧ polishing head

51‧‧‧ body shell

52‧‧‧ mounting table

53‧‧‧ Lower outer ring

54‧‧ Air Chamber

56‧‧‧ shaft

58‧‧‧ grinding gasket

60‧‧‧ polishing head

62‧‧‧ Grinding plate

64‧‧‧Rotary axis

66‧‧‧ Grinding plate

68‧‧‧Rotary axis

70‧‧‧Direct motion guiding member

72‧‧‧ Guide track

74‧‧‧Maintenance platform

76‧‧‧Maintenance platform

78‧‧‧ hanging the ring

80‧‧‧through holes

82‧‧‧Sliding ring

84‧‧‧Sliding ring spreader

86‧‧‧Up spring

88‧‧‧ hanging spring

90‧‧‧through hole

92‧‧‧Spiral jack

94‧‧‧stop sales

96‧‧‧linear axis

98‧‧‧jet

100‧‧ Air Room

102‧‧‧Air supply path

104‧‧‧Valve

106‧‧‧Air pump

108‧‧‧Latch

110‧‧‧ head

112‧‧‧ hook

14‧‧‧Tratch

116‧‧‧ hole

118‧‧‧stop plate

120‧‧‧Air circulation path

122‧‧‧Supporting components

124‧‧‧挟板

126‧‧‧ pole

128‧‧‧through holes

130‧‧‧through holes

138‧‧‧Conveyor

140‧‧‧Robot

142‧‧‧ robot arm

144‧‧‧Sucking head

146‧‧‧Conveyor

150, 152, 154‧‧‧ transport device

160‧‧‧ Guide rail

170‧‧‧ Guide rail

200‧‧‧Small sheet

210‧‧‧Intermediate sheet

Fig. 1 is a plan view showing the entire structure of a polishing apparatus according to a first embodiment.

Figure 2 shows a side view of an embodiment of a polishing head and a polishing table.

Figure 3 is an assembled perspective view of the polishing head.

Fig. 4 is an explanatory view showing a three-layer structure of a film body of a film frame.

Fig. 5 is an enlarged cross-sectional view showing an essential part of the attachment structure of the film frame with respect to the slide ring.

Fig. 6 is a side view showing the arrangement of the film body, the intermediate sheet, and the absorbing sheet.

38‧‧‧membrane body

200‧‧‧ followed by thin slices

210‧‧‧Intermediate sheet

G‧‧‧glass substrate

Claims (5)

A substrate polishing apparatus that supplies a pressurized fluid between a film body to which a suction sheet that sucks and holds a substrate is attached, and a mounting table on which the film body is attached, and which is pressurized by the pressure a pressure of a fluid, a polishing device that is sucked onto the absorbing sheet and held by the held substrate to the polishing plate, and is ground, characterized in that between the film body and the absorbing sheet Then, there is an intermediate sheet whose rigidity in the drawing direction is higher than the rigidity of the drawing direction of the absorbing sheet. The film system is constituted by the airtight holding layer and the strength maintaining layer. The intermediate sheet is attached to the underside of the strength maintaining layer. The substrate polishing apparatus according to claim 1, wherein the absorbing sheet is made of foamed urethane, and the intermediate sheet is made of polycarbonate, acryl, aluminum, stainless steel, glass or carbon fiber. Strengthened plastics. The substrate polishing apparatus according to claim 2, wherein the intermediate sheet is made of polycarbonate. The substrate polishing apparatus according to any one of claims 1 to 3, wherein the absorbing sheet is attached to a film body provided on the mounting table and is then passed through the intermediate sheet. A substrate polishing method using a substrate polishing apparatus according to any one of claims 1 to 4, The substrate is ground.