JP2940611B2 - Wafer polishing machine with retainer ring - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer polishing apparatus, and more particularly to a wafer polishing apparatus with a retainer ring for polishing a wafer by pressing the wafer against a rotating polishing plate while surrounding the periphery of the wafer with a retainer ring. .

[0002]

2. Description of the Related Art A wafer polishing apparatus disclosed in Japanese Patent Application Laid-Open No. 8-229808 is provided with a retainer ring surrounding an outer peripheral portion of a wafer, and polishing the wafer by pressing the retainer ring together with the wafer against a polishing platen. An apparatus is disclosed. Further, the wafer polishing apparatus comprises:
A method of adjusting the pressing force of the retainer ring by providing an annular tube between the retainer ring and the wafer holding head and adjusting the internal air pressure of the tube, and adjusting the pressing force by using a diaphragm A method is disclosed.

[0003]

However, in the conventional wafer polishing apparatus, when air is supplied to the tube, the weak portion expands more, and as a result, the retainer ring is pressed uniformly over the entire circumference. There is a drawback that you can not. When the pressing force becomes non-uniform in this way, the polishing pressure applied to the wafer also becomes non-uniform,
The wafer cannot be polished uniformly.

In the method of adjusting the pressing force of the retainer ring by the diaphragm, the required amount of pressing force may not be obtained because the amount of displacement of the retainer ring cannot be increased. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wafer polishing apparatus with a retainer ring that can uniformly press a retainer ring and increase a displacement amount of the retainer ring.

[0005]

According to the present invention, there is provided a wafer polishing apparatus for polishing a surface of a wafer by pressing the wafer against a rotating polishing table to achieve the above object. A head body that is arranged to face the head, a carrier that is vertically movably housed in the head body, that supports the wafer and presses the wafer against the polishing platen, and that is housed in the head body that is movably up and down. A retainer ring disposed concentrically on the outer periphery of the carrier and abutting against the polishing platen during polishing and holding the outer periphery of the wafer; a first space portion formed in the head body and pressing the carrier; and the retainer A second space portion for pressing the ring,
The first and second space portions concentrically divide one elastic sheet provided in the upper space of the carrier and the retainer ring of the head main body into at least two portions, and a central portion thereof is defined as a first space portion. The outer peripheral portion is a second space portion, and the first,
It is characterized in that the carrier and the retainer ring are pressed against the polishing platen by supplying compressed air to the second space to elastically deform the central portion and the outer peripheral portion of the elastic sheet.

According to another aspect of the present invention, there is provided a wafer polishing apparatus for polishing a surface of a wafer by pressing the wafer against a rotating polishing table, wherein the wafer is rotated and arranged to face the polishing table. Head body,
A carrier that is vertically movably housed in the head body, supports the wafer and presses the wafer against the polishing platen, and is vertically movably housed in the head body and is concentric with the outer periphery of the carrier. Placed,
A retainer ring that contacts the polishing platen during polishing and holds the outer periphery of the wafer, and the head body and the carrier
A closed first space formed between the O-ring and pressing the carrier, a head body and the retainer.
And a sealed second space portion formed between the first and second space portions through an O-ring and pressing the retainer ring, and pressurized air is directly supplied to the first and second space portions to form a carrier and a retainer. A ring is pressed against the polishing platen. Furthermore, in order to achieve the above object, the present invention provides a method in which a wafer is pressed against a rotating polishing platen,
In a wafer polishing machine for polishing the surface of wafers,
And a head body arranged to face the polishing platen
The head body is vertically movably stored in the head body.
Support the wafer and press the wafer against the polishing platen
And the head body can move up and down freely.
Stored and concentrically arranged around the carrier
During polishing, it comes into contact with the polishing platen and
Retainer ring and formed inside the head body
A first space for pressing the carrier and the retainer;
And a second space portion that presses the nulling.
The first and second space portions are provided with a carrier and a hole of the head body.
It is arranged in the upper space of the
It is composed of two elastic sheets placed, and the two elastic sheets
The sheet is concentrically divided into at least two parts, and the two elastic sheets
The space at the center formed by being sandwiched between
And an outer peripheral portion formed between the two elastic sheets.
Is used as the second space portion .

According to the first aspect of the present invention, the wafer is pressed against the polishing cloth by supplying pressure air to the first space portion and elastically deforming the central portion of the elastic sheet by air pressure to press the carrier. be able to. Then, pressure air is supplied to the second space portion, and the outer peripheral portion of the elastic sheet is elastically deformed by air pressure to press the retainer ring, so that the retainer ring can be uniformly pressed against the polishing pad. Accordingly, the present invention can uniformly polish the entire polished surface of the wafer, and can take a longer moving stroke of the retainer ring than that using a diaphragm, so that a sufficient pressing force can be obtained. Can be.

According to the second aspect of the present invention, the wafer can be pressed against the polishing pad by supplying pressure air to the first space portion and directly pressing the carrier with the air pressure. Then, by supplying the pressurized air to the second space portion and directly pressing the retainer ring with the air pressure, the retainer ring can be uniformly pressed against the polishing pad. Therefore, according to the present invention, the entire polishing surface of the wafer can be uniformly polished, and the moving stroke of the retainer ring can be longer than that using a diaphragm, so that a sufficient pressing force can be obtained. it can.

According to a third aspect of the present invention, a rubber, metal, or plastic sheet is used as the elastic sheet. That is, any sheet that can be elastically deformed by the pressure of pressurized air to press the carrier or the retainer ring can be applied as the elastic sheet of the present invention. According to the fourth aspect of the present invention, since the elastic sheet is constituted by one sheet, the number of parts can be reduced.

According to a fifth aspect of the present invention, the elastic sheet comprises a circular sheet disposed inside and an annular sheet disposed outside the circular sheet. 6. The invention according to 6, wherein the elastic sheet comprises:
It is composed of two elastic sheets arranged one above the other. That is, according to the fifth and sixth aspects of the invention,
Even if two elastic sheets are used, the first space portion and the second space portion can be formed.

According to the present invention, an air blowing member is provided on the lower surface of the carrier, and air is blown from the air blowing member toward the wafer to form a pressure fluid layer between the carrier and the wafer. The wafer is pressed against the polishing platen via the pressure fluid layer to polish the wafer. This allows
Since the wafer is uniformly pressed against the polishing platen, the entire surface of the wafer can be uniformly polished.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a wafer polishing apparatus with a retainer ring according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an overall configuration diagram of a wafer polishing apparatus to which a wafer polishing apparatus with a retainer ring according to the present invention is applied. As shown in FIG. 1, the wafer polishing apparatus 10 includes a polishing platen 12 and a wafer holding head 14. The polishing platen 12 is formed in a disk shape, and a polishing cloth 16 is provided on an upper surface thereof. Further, a spindle 18 is connected to a lower portion of the polishing platen 12, and the spindle 18 is connected to an output shaft (not shown) of a motor 20. The polishing platen 12 rotates in the direction of arrow A by driving the motor 20,
A slurry is supplied from a nozzle (not shown) onto the polishing cloth 16 of the rotating polishing table 12.

FIG. 2 is a longitudinal sectional view of the wafer holding head 14. The wafer holding head 14 shown in FIG. 1 includes a head body 22, a carrier 24, a guide ring 26, a retainer ring 28, a rubber sheet (elastic sheet) 30, and the like. The head main body 22 is formed in a disk shape, and the head main body 22 is rotated in the direction of arrow B by a motor (not shown) connected to the rotating shaft 32. Air supply paths 34, 36, and 37 are formed in the head main body 22, and these air supply paths 34, 36, and 37 communicate with air supply paths 38, 40, and 41 that are formed on the rotation shaft 32. Have been. A pump 44 is connected to the air supply path 38 via a regulator 42A.
Is connected to the pump 44 via a regulator 42B, and the air supply path 41 is connected to the pump 44 via a regulator 42C.

The carrier 24 is formed in a disk shape and is arranged coaxially with the head main body 22 below the head main body 22. Further, a concave portion 25 is formed on the lower surface of the carrier 24, and a porous plate 52 having air permeability is formed in the concave portion 25.
Is stored. The air chamber 27 is located above the porous plate 52.
The air chamber 27 is connected to an air supply path 53, and the air supply path 53 is connected to the above-described air supply path 37. Therefore, the compressed air from the pump 44 is supplied to the air chamber 27 via the air supply passages 37, 41, and 53, and then passes through the porous plate 52 and is blown downward from the lower surface of the porous plate 52. Thereby, carrier 2
The pressure of 4 is transmitted to the wafer 54 via the pressure air layer 55, and the wafer 54 is uniformly pressed against the polishing pad 16. Further, the pressing force of the wafer 54 against the polishing pad 16 can be controlled by adjusting the air pressure with the regulator 42C. Wafer 5 with carrier 24
When pressing the polishing pad 4 directly against the polishing pad 16, if there is dust between the carrier 24 and the wafer 54, the pressing force of the carrier 24 cannot be uniformly transmitted to the entire surface of the wafer 54. When the wafer 54 is pressed through the air layer 55, the pressing force of the carrier 24 is reduced even if there is dust between the carrier 24 and the wafer 54.
It can be transmitted uniformly over the entire surface.

Since the wafer holding head 14 controls the pressing force applied to the carrier 24 to move the carrier 24 up and down, the polishing pressure of the wafer 54 (the force pressing the wafer 54 against the polishing pad 16) is controlled. The control of the polishing pressure is easier than the control of the polishing pressure of the wafer 54 by directly controlling the pressure of the pressure air layer 55. That is, in the wafer holding head 14, the polishing pressure of the wafer 54 can be controlled by controlling the vertical position of the carrier 24. The air blown out of the porous plate 52 is exhausted to the outside through an exhaust hole (not shown) formed in the retainer ring 28.

The porous plate 52 has a large number of air passages therein. For example, a porous plate made of a sintered body of a ceramic material is used. The rubber sheet 30 is formed in a single disk shape with a uniform thickness. The rubber sheet 30 is fixed to the head body 22 by a stopper 48 via an O-ring 46, and the rubber sheet 30 is
Is divided into a central portion 30A and an outer peripheral portion 30B. As described later, the central portion 30A of the rubber sheet 30 presses the carrier 24, and the outer peripheral portion 30B presses the retainer ring 28. In the present embodiment, the rubber sheet 30 is used as the elastic sheet. However, the present invention is not limited to this. Any sheet made of a material such as plastic that elastically deforms by a fluid pressure such as an air pressure may be used.

On the other hand, below the head body 22, a space (first space portion) 50 is formed which is sealed by the rubber sheet 30 and the O-ring 46. The air supply path 36 communicates with the space 50. Therefore, compressed air is supplied from the air supply path 36 to the space 50 and the rubber sheet 3
0 is elastically deformed by air pressure to form the carrier 2
By pressing the wafer 54 against the upper surface of the polishing pad 4, a pressing force of the wafer 54 against the polishing pad 16 can be obtained. Further, if the air pressure is adjusted by the regulator 42B, the pressing force of the wafer 54 can be controlled.

The guide ring 26 is formed in a cylindrical shape, and is disposed coaxially with the head body 22 below the head body 22. In addition, the guide ring 26 is attached to the rubber sheet 3.
0 is fixed to the head main body 22. Thus, the rotational force from the head body 22 is transmitted to the guide ring 26 via the rubber sheet 30. Note that reference numeral 5
Reference numerals 6 and 58 denote O-rings for sealing.

A retainer ring 28 is disposed between the guide ring 26 and the carrier 24. The retainer ring 28 has an outer diameter substantially equal to the inner diameter of the guide ring 26, and is slidably supported on an inner peripheral surface 26 </ b> A of the guide ring 26. Thereby, the retainer ring 28
It is guided by the inner peripheral surface 26A of the guide ring 26 and slides in the direction C indicated by the arrow in the figure.

The retainer ring 28 is formed with a plurality of straight grooves 60 at predetermined positions on the outer peripheral surface thereof. The straight groove 60 is provided for the retainer ring 2.
8 and is formed along the moving direction of the straight groove 60.
, A pin 62 fixed to the guide ring 26 side is engaged. As a result, the retainer ring 28 is prevented from falling off the guide ring 26, and the retainer ring 28 is
8 can be moved in the pressing direction.

On the other hand, on the lower outer peripheral portion of the head main body 22,
Outer peripheral portion 30B of rubber sheet 30, O-ring 46, and O
An annular space (second space portion) 66 sealed by the ring 56 is formed. The air supply path 34 communicates with the space 66. Therefore, the air supply path 34
When compressed air is supplied to the space 66 from above, the outer peripheral portion 30B of the rubber sheet 30 is elastically deformed by air pressure as shown in FIG. 2 and pushes the annular upper surface of the retainer ring 28. This allows
The retainer ring 28 is pressed, and the annular lower surface of the retainer ring 28 is pressed against the polishing pad 16. The pressing force of the retainer ring 28 can be controlled by adjusting the air pressure with the regulator 42A.

Next, the operation of the wafer holding head 14 of the wafer polishing apparatus 10 configured as described above will be described. First, the pump 44 is driven to supply compressed air to the air chamber 27 through the air supply paths 41, 37, and 53, and the pressing force of the carrier 24 is applied between the porous plate 52 and the wafer 54 over the entire surface of the wafer 54. Pressure fluid layer 55 that uniformly transmits
To form

Next, compressed air from the pump 44 is supplied to the space 50 via the air supply passages 40 and 36, and the center 30A of the rubber sheet 30 is elastically deformed by the internal air pressure to press the carrier 24, The wafer 54 is pressed against the polishing pad 16 via the pressurized air layer 55. Then, the air pressure is adjusted by the regulator 42B to control the internal air pressure to a desired pressure, and the pressing force of the wafer 54 against the polishing pad 16 is made constant.

Next, compressed air from the pump 44 is supplied to the space 66 via the air supply passages 38 and 34, and the outer peripheral portion 30B of the rubber sheet 30 is elastically deformed by internal air pressure to press the retainer ring 28. The retainer ring 28 is pressed against the polishing pad 16. And the regulator 42A
The air pressure is adjusted to control the internal air pressure to a desired pressure, and the pressing force of the retainer ring 28 against the polishing pad 16 is kept constant. Here, the pressing force P1 per unit area of the wafer 54 against the polishing pad 16 and the pressing force P2 per unit area of the retainer ring 28 against the polishing pad 16 are shown.
For example, in the case of a soft polishing cloth (a polishing cloth in which the upper layer is a hard foamed polyurethane and the lower layer is a sponge), P1 <
Set to P2. Thereafter, the wafer holding head 14 is rotated to start polishing the wafer 54.

In the present embodiment, since the rubber sheet 30 is used as the pressing means of the retainer ring 28, it can be elastically deformed more uniformly than an airbag or a tube, and the retainer ring 28 can be retained by the guide ring 26. Since the guide is movably guided in the pressing direction of the ring, the retainer ring can be stably pressed with a uniform pressure.

Therefore, in this embodiment, the entire polishing surface of the wafer 54 can be polished more uniformly than in a conventional polishing apparatus using an airbag or a tube. Further, in the present embodiment, the moving stroke of the retainer ring 28 can be made larger than that in which a diaphragm is used as the pressing means. FIG. 3 is an enlarged sectional view of a main part of a second embodiment of the wafer holding head, and the same or similar members as those of the first embodiment shown in FIG. The description is omitted.

The wafer holding head 15 shown in FIG. 3 includes a guide ring 70 for slidingly supporting the outer peripheral surface of the retainer ring 28 and a guide ring 72 for slidingly supporting the inner peripheral surface of the retainer ring 28. The retainer ring 28 is retained by the guide rings 70 and 72.
Are movably guided in the pressing direction. A space (second space portion) 74 is formed between the guide rings 70 and 72 and the holding head main body 22, and the air supply passage 34 communicates with the space 74. Reference numerals 76, 78 and 80 are
An O-ring seals the space 74, and an O-ring 82 seals the space (first space portion) 50. When compressed air is supplied from the air supply path 36 to the space 50,
The carrier 24 is pushed downward by air pressure, and presses the wafer 54 against the polishing pad 16 via the pressure air layer 55.

A stopper plate 84 is fixed to the upper surface of the retainer ring 28. The stopper plate 84 prevents the guide rings 70 and 72 from falling off.
A stopper 86 protruding inward is formed at a lower portion of the retainer ring 28, and the stopper 86 contacts the lower surface 72 </ b> A of the guide ring 72, thereby restricting the upper position of the retainer ring 28.

According to the wafer holding head 15 configured as described above, when compressed air is supplied to the space 74 from the air supply path 34, the retainer ring 28 is pressed downward by the air pressure and pressed against the polishing pad 16. Can be Further, by adjusting the air pressure of the compressed air, the pressing force of the retainer ring 28 against the polishing pad 16 can be controlled. In the present embodiment, the guide ring 7 forming the space 74 is used.
0, 72 and the head body 22 constitute a cylinder body,
The air cylinder mechanism is constituted by making the retainer ring 28 function as a rod. Therefore, according to the present invention, the retainer ring 28 can be pressed with a uniform pressure over the entire circumference, and the moving stroke can be longer than that of the airbag or the tube, so that a sufficient pressing force can be obtained. .

By the way, in the first embodiment shown in FIG.
One rubber sheet 30 is divided into two and the first space 5
Although 0 was formed and the second space 66 was formed in the outer peripheral portion, the present invention is not limited to this. For example, as shown in FIG. 4, a rubber sheet is
And an annular sheet 9 arranged outside the circular sheet 90
And 2. In this case, the outer peripheral portion of the sheet 90 and the inner peripheral portion of the sheet 92 are overlapped with each other, an annular stopper 94 is passed through the overlapping portion, and the stopper 94 is attached to the head body 22. Thereby, the first space 50
Is sealed by the self-sealing property of the overlapping portion of the sheets 90 and 92. On the other hand, the outer periphery of the sheet 92 is
2 and the guide ring 26, and the head body 22 and the guide ring 26 are fastened with a plurality of bolts 96, and the outer peripheral portion of the sheet 92 is sandwiched and held between the head body 22 and the guide ring 26. Thus, the second space 66 is sealed by the self-sealing property of the outer peripheral portion of the sheet 92.

As shown in FIG. 5, two rubber sheets 100 and 102 may be arranged one above the other. In this case, in order to form the first space 50, the sheet 100,
An annular stopper 104 is passed through the base 102, and the stopper 104 is attached to the head main body 22. Thus, the first space 50 is hermetically sealed by the self-sealing property of the overlapped portion of the sheets 100 and 102. On the other hand, sheets 100, 1
02 is sandwiched between the head body 22 and the guide ring 26, and the head body 22 and the guide ring 26
Are fastened with a plurality of bolts 106, and the sheet 100,
The outer peripheral portion of 102 is held between the head body 22 and the guide ring 26 with pressure. Thus, the second space 66 is hermetically sealed by the self-sealing property of the outer periphery of the sheets 100 and 102. In addition, the sheet 100 is formed with an air introduction hole 100A that is connected to the air supply path 36 and introduces air into the first space 50, and is connected to the air supply path 34 so that air is supplied to the second space 50. An air introduction hole 100B for introducing the air into the portion 66 is formed.

FIG. 6 is a plan view of the holding head 214 having one rubber sheet divided into three, and FIG. 7 is a longitudinal sectional view taken along the line 7-7 in FIG. The holding head 214 shown in FIG. 7 includes a head main body 222, a carrier 224, a guide ring 226, a polishing surface adjusting ring 228, a retainer ring 230, a rubber sheet 232, a differential transformer 234, a pressing member 236, and the like.

The head body 222 is formed in a disk shape, and has a rotating shaft 238 connected to the upper surface thereof, and is rotated in the direction of arrow B by a motor (not shown) connected to the rotating shaft 238. Further, air supply paths 240, 242, 244 are formed in the head main body 222.
The air supply path 240 extends outside the holding head 214 as shown by a two-dot chain line in FIG.
6A is connected to the air pump 248. Similarly, the air supply paths 242 and 244 extend outside the holding head 214, and the air supply path 242 is connected to the regulator 246.
B to the pump 240 and to the air supply 244
Are connected to the pump 240 via the regulator 246C.

The carrier 224 is formed in a substantially columnar shape, and is disposed coaxially with the head main body 222 below the head main body 222. Further, a concave portion 225 is formed on the lower surface of the carrier 224, and the porous plate 250 having air permeability is accommodated in the concave portion 225. Air passages 252, 252 formed in the carrier 224 are formed in the porous plate 250.
Are communicated, and these air paths 252, 252
As shown by a two-dot chain line in the figure, it extends outside the holding head 214 and is connected to a suction pump 276.
Therefore, when the suction pump 276 is driven, the wafer 254 is sucked by the porous plate 250 and held by the porous plate 250. The porous plate 25
Numeral 0 has a large number of air passages inside, for example, a sintered body of a ceramic material is used.

The carrier 224 includes a carrier 224
Air supply passages 2 having jet ports formed on the outer periphery of the lower surface of the
78, 278... (Only two locations are shown in FIG. 6). The air supply passages 278, 278,... Extend outside the holding head 214 as indicated by a two-dot chain line in the drawing.
It is connected to an air pump 248 via a regulator 246D. Therefore, the compressed air from the air pump 248 is blown out to the air chamber 256 between the porous plate 250 and the wafer 254 via the air supply paths 278, 278,. Thus, a pressure air layer is formed in the air chamber 256, and the pressing force of the carrier 224 is transmitted to the wafer 254 via the pressure air layer. Wafer 254 is
It is pressed against the polishing pad 216 by the pressing force transmitted through the pressure air layer. The air supply path 27
The air blown out from 8, 278,... Is exhausted to the outside through an exhaust hole (not shown) formed in the polishing surface adjusting ring 228.

On the other hand, the head body 222 and the carrier 224
A single rubber sheet 232 is disposed between the two. This rubber sheet 232 is formed in a disk shape with a uniform thickness. The rubber sheet 232 is fixed to the lower surface of the head main body 222 by two large and small annular stoppers 258 and 260. Further, gaps between the stoppers 258 and 260 and the head body 222 are sealed by the rubber sheet 232. Thereby, the rubber sheet 232
The center part 232A and the middle part 2
32B and a middle part 232B and an outer peripheral part 232C with a stopper 258 as a boundary. That is, the rubber sheet 232 is divided into three parts by the stoppers 258 and 260, the central part 232A thereof presses the carrier 224, the intermediate part 232B presses the pressing member 236, and the outer peripheral part 232C presses the polishing surface adjusting ring 228. Function as an airbag for

In the air bag, the rubber sheet 23
The air supply path 240 is communicated with an air bag 262 defined by a central portion 232A of the second air supply path. Therefore, when compressed air is supplied from the air supply path 240 to the airbag 262, the central portion 232A of the rubber sheet 232 is elastically deformed by air pressure and presses the upper surface of the carrier 224. As a result, the wafer 254 with respect to the polishing cloth 216
Pressing force can be obtained. Further, if the air pressure is adjusted by the regulator 246A, the pressing force (polishing pressure) of the wafer 254 can be controlled.

The guide ring 226 is formed in a cylindrical shape, and is disposed coaxially with the head main body 222 below the head main body 222. The guide ring 26 is fixed to the head main body 222 via a rubber sheet 232. Between the guide ring 226 and the carrier 224,
A polishing surface adjustment ring 228 is provided. Above the polishing surface adjusting ring 228, an annular airbag 264 defined by the outer peripheral portion 232C of the rubber sheet 232 and the stopper 258 is formed. This airbag 2
The air supply passage 244 communicates with the air supply passage 64. Therefore, when compressed air is supplied from the air supply path 244 to the airbag 264, the outer peripheral portion 232 of the rubber sheet 232 is
C is elastically deformed by air pressure to press the annular upper surface 228A of the polishing surface adjusting ring 228, and the annular lower surface 228B of the polishing surface adjusting ring 228 is pressed against the polishing pad 216. The pressing force of the polishing surface adjusting ring 228 can be controlled by adjusting the air pressure with the regulator 246C.

The carrier 224 and the polishing surface adjusting ring 2
A pressing member 236 is arranged between the pressing member 236 and the pressing member 236. The pressing member 236 includes a main body 236A, a head 236B, support arms 236C and 236C, and legs 236D and 236.
D. In addition, the head 236B, the support arm 236C, and the leg 236D of the pressing member 236 are formed at regular intervals of three as shown by the dotted lines in FIG.

The main body 23 of the pressing member 236 shown in FIG.
6A is an opening 2 formed in the polishing surface adjusting ring 228.
29. The head 236B of the pressing member 236 is formed integrally with the main body 236A, and is disposed in a gap between the carrier 224 and the polishing surface adjustment ring 228. Above the head 236B, the intermediate portion 232B of the rubber sheet 232 and the stopper 25
Annular airbag 2 defined by 8, 260
66 are formed. The air supply path 242 communicates with the air bag 266. Therefore, when compressed air is supplied from the air supply path 242 to the airbag 266, the intermediate portion 232B of the rubber sheet 232 is elastically deformed by air pressure and presses the head 236B of the pressing member 236. Thereby, the lower surface 237 of the leg 236 </ b> D of the pressing member 236 is pressed against the polishing pad 216. The pressing force of the pressing member 236 can be controlled by adjusting the air pressure with the regulator 246B. Also,
The leg 236D is disposed in a through hole 228C formed in the polishing surface adjusting ring 228. Further, the pressing member 236 is used to prevent thermal expansion due to polishing processing heat.
The lower surface 237, which is formed by using amber having an extremely small coefficient of thermal expansion as a base material and is pressed by the polishing cloth 216, is diamond-coated so that the polishing cloth 216 is not polished.

On the other hand, the support arm 2 of the pressing member 236
A differential transformer 234 for detecting the amount of polishing of the wafer 254 is provided at the tip of 36C. The differential transformer 234 includes a core 270, a bobbin 272, and a contact 274. The bobbin 272 is fixed to a distal end of a support arm 236C of a pressing member 236, and the core 270 is inserted into the bobbin 272. Are movably arranged up and down. The contact 274 is provided below the core 270, and the contact 274 is in contact with the carrier 224. An arithmetic unit (not shown) is connected to the bobbin 272, and the arithmetic unit calculates a polishing amount of the wafer 254 based on a vertical movement amount of the core 270 with respect to the bobbin 272.

By the way, a retainer ring 230 is vertically movably fitted on the outer periphery of the lower part of the carrier 224. The retainer ring 230 contacts the polishing pad 216 during polishing of the wafer 254. Then, the wafer 254 is moved laterally by the rotational force of the polishing pad 216 and is brought into contact with the inner peripheral surface of the retainer ring 230, thereby preventing the wafer 254 from jumping out of the carrier 224 by the retainer ring 230. ing.

Further, since the retainer ring 230 is made of resin, the retainer ring 230 is deformed from its original shape by the pressing force from the wafer 254 and elastically deforms into a shape following the peripheral shape of the wafer 254. Therefore, the wafer 254
It is pressed in a state of surface contact with the retainer ring 230. In addition, as long as it is elastically deformed by the pressing force, a retainer ring made of metal, not limited to resin, may be applied.

Next, the operation of the wafer polishing apparatus configured as described above will be described. First, the holding head 214
Then, the suction pump 276 is driven to suck and hold the wafer 254 to be polished on the porous plate 250. Next, the holding head 214 is lowered, and the lowering movement is stopped at a position where the contact surface of the polishing surface adjustment ring 228 contacts the polishing pad 216. And the suction pump 27
6 is stopped, the suction of the wafer 254 is released, and the wafer 254 is placed on the polishing pad 216.

Next, the air pump 248 is driven to supply compressed air to the space 256 via the air path 278, and a pressure air layer is formed in the air chamber 256. At this time, the supply amount of compressed air is adjusted by controlling the regulator 246D, and the pressure of the pressure air layer is set to a predetermined pressure. Next, the compressed air from the pump 248 is supplied to the air supply path 240.
Is supplied to the airbag 262 via the
The central portion 232 </ b> A is elastically deformed by the internal air pressure to press the carrier 224, and the wafer 254 is pressed against the polishing pad 216 via the pressure air layer. Then, the air pressure is adjusted by the regulator 246A to control the internal air pressure to a desired pressure, and the wafer 25
The pressing force of No. 4 is kept constant.

At the same time, the compressed air from the pump 248 is supplied to the air bag 2 through the air supply path 244.
64, and the outer peripheral portion 232 </ b> C of the rubber sheet 232 is elastically deformed by the internal air pressure to form the polishing surface adjusting ring 228.
Is pressed, and the polishing surface adjusting ring 228 and the retainer ring 2 are pressed.
30 is pressed against the polishing pad 216. Then, compressed air from the pump 240 is supplied to the airbag 266 via the air supply path 242, and the intermediate portion 232 </ b> B of the rubber sheet 232 is elastically deformed by internal air pressure to press the pressing member 2.
36, and the lower surface 237 of the pressing member 236 is
Press 16 Thereafter, the polishing platen 212 and the holding head 214 are rotated to start polishing the wafer 254.

During the polishing of the wafer 254, the wafer 254 moves in the horizontal direction due to the rotation of the polishing pad 216, and is polished while its peripheral edge is pressed against the retainer ring 230.
Is the wafer 25 by the pressing force from the wafer 254.
4 is elastically deformed into a shape along the shape of the periphery. As a result, the wafer 254 is pressed against the retainer ring 230 in a state where the wafer 254 is in surface contact with the retainer ring 230, and the pressure applied to the wafer from the retainer ring 230 is dispersed.

On the other hand, the polishing amount of the wafer 254 during polishing is based on the descending amount of the contact 274, that is, the descending amount of the core 270 because the contact 274 of the differential transformer 234 is in contact with the carrier 224. Is calculated by the arithmetic unit. When the polishing amount calculated by the arithmetic unit reaches a preset polishing end point, the wafer polishing apparatus is stopped, and the polishing of the wafer 254 is completed. Thereby, polishing of one wafer 254 is completed, and when polishing the second and subsequent wafers 254,
The above steps may be repeated.

In this embodiment, an example in which a rubber sheet is used as the elastic sheet has been described. However, if the elastic sheet can be elastically deformed by pressurized air to press the carrier or the retainer ring, the rubber sheet is used instead. A metal sheet or a plastic sheet may be used. Also,
Instead of the elastic sheet, a shape memory alloy whose deformation varies with temperature is applied, and the heating temperature of the shape memory alloy is controlled by a heater to control the deformation of the shape memory alloy. The ring and the carrier may be pressed.

[0050]

As described above, according to the wafer polishing apparatus with a retainer ring according to the present invention, pressure air is supplied to the first space portion, and the center portion of the elastic sheet is elastically deformed by the air pressure to form the carrier. By pressing, the wafer can be pressed against the polishing cloth, and by supplying pressurized air to the second space portion, the outer peripheral portion of the elastic sheet is elastically deformed by air pressure to press the retainer ring,
The retainer ring can be pressed uniformly against the polishing cloth. Accordingly, the present invention can uniformly polish the entire polished surface of the wafer, and can take a longer moving stroke of the retainer ring than that using a diaphragm, so that a sufficient pressing force can be obtained. Can be.

According to the present invention, the wafer can be pressed against the polishing cloth by supplying the pressurized air to the first space and directly pressing the carrier with this air pressure. The retainer ring can be uniformly pressed against the polishing pad by supplying pressure air to the polishing pad and directly pressing the retainer ring with this air pressure.
Therefore, according to the present invention, the entire polishing surface of the wafer can be uniformly polished, and the moving stroke of the retainer ring can be longer than that using a diaphragm, so that a sufficient pressing force can be obtained. it can.

[Brief description of the drawings]

FIG. 1 is an overall structural diagram of a wafer polishing apparatus with a retainer ring according to a first embodiment.

FIG. 2 is a longitudinal sectional view of a wafer holding head of the wafer polishing apparatus shown in FIG.

FIG. 3 is an enlarged sectional view of a main part of a wafer polishing apparatus with a retainer ring according to a second embodiment.

FIG. 4 shows a first example in which an elastic sheet is formed by two rubber sheets.
Sectional view showing an embodiment of the present invention.

FIG. 5 shows a second example in which an elastic sheet is constituted by two rubber sheets.
Sectional view showing an embodiment of the present invention.

FIG. 6 is a plan view of a wafer holding head according to a third embodiment.

FIG. 7 is a longitudinal sectional view of the wafer holding head shown in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Wafer polishing apparatus 12 ... Polishing surface plate 14 ... Wafer holding head 16 ... Polishing cloth 22 ... Head main body 24 ... Carrier 26 ... Guide ring 28 ... Retainer ring 30 ... Rubber sheet 52 ... Porous plate 54 ... Wafer

Claims (5)

(57) [Claims] 1. A wafer polishing apparatus for polishing a surface of a wafer by pressing the wafer against a rotating polishing table, wherein the head body rotates and is arranged to face the polishing table; A carrier that is housed freely and supports the wafer and presses the wafer against the polishing platen; and a carrier that is housed in the head body so as to be movable up and down and is concentrically arranged on the outer periphery of the carrier. A retainer ring that contacts the board and holds the outer periphery of the wafer; and a first ring formed in the head body and pressing the carrier.
A space portion and a second space portion that presses the retainer ring, wherein the first and second space portions are formed by a single elastic sheet provided in a space above the carrier of the head body and the retainer ring. At least two portions are concentrically formed, and the center portion is defined as a first space portion, and the outer peripheral portion is defined as a second space portion.
A wafer polishing apparatus with a retainer ring, characterized in that a pressurized air is supplied to a second space portion to elastically deform a central portion and an outer peripheral portion of an elastic sheet to press a carrier and a retainer ring against the polishing platen. 2. A wafer polishing apparatus for polishing a surface of a wafer by pressing the wafer against a rotating polishing table, wherein the head body rotates and is arranged to face the polishing table, and the head body moves vertically to the head body. A carrier that is housed freely and supports the wafer and presses the wafer against the polishing platen; and a carrier that is housed in the head body so as to be movable up and down and is concentrically arranged on the outer periphery of the carrier. A retainer ring that abuts the board and holds the outer periphery of the wafer; and an O-ring between the head body and the carrier.
It made that the first space portion sealed shape for pressing said carrier, and
An O-ring is interposed between the head body and the retainer ring.
A closed second press formed on the retainer ring
And a space portion, wherein a pressurized air is directly supplied to the first and second space portions to press a carrier and a retainer ring against the polishing platen. 3. A wafer is pressed against a rotating polishing table.
Wafer polishing machine to polish the surface of the wafer
hand, A head book that rotates and faces the polishing platen
Body and The head body is movably housed in the up-down direction,
Press the wafer against the polishing platen while supporting the wafer
Career and While being stored in the head body so as to be movable up and down,
Arranged concentrically on the outer circumference of the carrier and polished during polishing
A retainer that abuts the surface plate and holds the outer periphery of the wafer
Nulling, A first portion formed in the head body and pressing the carrier;
Space part and second space part pressing the retainer ring
And formed from The first and second spaces are provided with a carrier and a head of the head body.
Stacked in the upper space of the retainer ring
Composed of two elastic sheets arranged in
The elastic sheet is concentrically divided into at least two parts, and the two elastic sheets
The space at the center formed by being sandwiched by sheets is
An outer portion formed by being sandwiched between the two elastic sheets
A peripheral space defined as the second space portion;
Wafer polisher with tenoring. Wherein said elastic sheet, according to claim 1, characterized in that rubber, metal, or plastic, or
4. The wafer polishing apparatus with a retainer ring according to 3 . 5. providing the air blowing member to the lower surface of the carrier, by blowing air from the air blowing member toward the rear surface of the wafer, to form a pressure fluid layer between the carrier and the wafer, the pressure claim 1, 2, or 3 retainer ring with a wafer polishing apparatus, wherein the via fluid layer pressing said wafer to said polishing table.