JP2005011999A - Workpiece holding head and polishing apparatus having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a workpiece holding head wherein the wafer quality (flatness) is maintained, the wafer edge is prevented from excess abrasion, and the retainer ring is kept in its optimum shape. <P>SOLUTION: The workpiece holding head 14 has a carrier 24 for holding a workpiece W and pressing the surface of the workpiece W to a polishing pad 20, and an annular member 50 which is arranged along the periphery of the carrier 24, surrounds the workpiece W, and abuts on the polishing pad 20. The annular member 50 has an inclination adjusting means 80 which adjusts the inclination of the lower surface of the annular member 50 relative to the horizontal plane. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a work holding head and a polishing apparatus having the work holding head, and in particular, a work holding head suitable for polishing a wafer or the like by a chemical mechanical polishing (CMP) method and the work holding head. The present invention relates to a polishing apparatus having
[0002]
[Prior art]
Polishing of a wafer by CMP is performed by pressing the wafer against a rotating polishing pad with a predetermined pressure while rotating the wafer, and supplying an abrasive slurry between the polishing pad and the wafer. At this time, the wafer is surrounded by a retainer ring, and the back side is held by the carrier and pressed against the polishing pad.
[0003]
As such a conventional substrate polishing apparatus, various proposals have been made (for example, see Patent Document 1). FIG. 5 is a front view showing a configuration of a main part of a conventional wafer holding head. In the figure, a protective sheet 1 made of various materials is attached to a retainer ring holder 3 disposed around a carrier 2 by adhering a peripheral edge, and the retainer ring 4 is adhered to a lower portion of the protective sheet 1 by adhesion. It is attached.
[0004]
The retainer ring 4 presses the polishing pad 20 to reduce the impact applied to the end portion (edge portion) of the wafer W, and the polishing amount of the edge portion is controlled so as not to cause the surface sagging of the edge portion. That is, the pressure for pressing the retainer ring 4 against the polishing pad 20 greatly affects the shape of the edge portion of the wafer W. The retainer ring 4 is usually manufactured so that the lower surface is flat.
[0005]
[Patent Document 1]
JP 2000-317819 A
[0006]
[Problems to be solved by the invention]
However, when the lower surface of the retainer ring 4 is made flat, heat is generated by the sliding between the retainer ring 4 and the polishing pad 20, and the retainer ring 4 is thermally deformed, or a subtle dimensional error of the lower surface of the retainer ring 4. For example, the form of the pressure distribution that presses the polishing pad 20 of the retainer ring 4 changes greatly, and the inner peripheral portion of the retainer ring 4 is strongly pressed or the outer peripheral portion is pressed strongly. Due to these phenomena, the shape of the edge portion of the wafer W varies greatly, and the quality of the polished wafer W is greatly deteriorated.
[0007]
In addition, there are some troubles in which the quality of the wafer W varies and a malfunction occurs such that the wafer W gets under the retainer ring 4 during processing.
[0008]
As described above, the inclination of the lower surface of the retainer ring 4 with respect to the horizontal affects the pressure distribution of the edge portion of the wafer W and the retainer ring 4 itself, and is a factor that is dominant in the quality of the wafer W (particularly the shape of the edge portion). Become. For this reason, the quality control of the retainer ring 4 is severe, which has been a heavy burden on equipment maintenance.
[0009]
Moreover, even if the shape of the lower surface of the retainer ring 4 can be set to an optimum state, there is a problem that this state cannot be maintained for a long time due to wear of the retainer ring 4.
[0010]
The present invention has been made in view of such circumstances. The contact form between the retainer ring and the polishing pad is stabilized, the quality (flatness) of the edge portion of the wafer is maintained, and the excess of the wafer edge portion is achieved. An object of the present invention is to provide a substrate polishing apparatus capable of preventing wear and maintaining the retainer ring in an optimum shape.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a carrier that holds a workpiece and presses the surface of the workpiece against a polishing pad, and is disposed on the outer periphery of the carrier so as to surround the workpiece and to contact the polishing pad. A work holding head comprising: a ring-shaped member that is in contact with the ring-shaped member, wherein the lower surface of the ring-shaped member is inclined with respect to a horizontal plane.
[0012]
The present invention also provides a carrier that holds the workpiece and presses the surface of the workpiece against the polishing pad, and a ring-shaped member that is disposed on the outer periphery of the carrier and surrounds the periphery of the workpiece and is in contact with the polishing pad. A workpiece holding head, wherein the ring-shaped member is provided with an inclination adjusting means capable of adjusting an inclination of a lower surface of the ring-shaped member with respect to a horizontal plane, and the workpiece holding head. A polishing apparatus is provided.
[0013]
Further, the present invention provides a protective sheet made of an elastic material that presses the workpiece against the polishing pad, a ring-shaped member that holds the periphery of the protective sheet and contacts the polishing pad, and a portion corresponding to the region of the workpiece A workpiece holding head comprising a carrier that presses the protective sheet toward the workpiece, wherein the ring-shaped member is provided with an inclination adjusting means capable of adjusting an inclination of a lower surface of the ring-shaped member with respect to a horizontal plane. A work holding head and a polishing apparatus having the work holding head are provided.
[0014]
According to the present invention, there is provided an inclination adjusting means capable of adjusting the inclination of the lower surface of the ring-shaped member, that is, the retainer ring with respect to the horizontal plane, or the lower surface of the retainer ring is inclined with respect to the horizontal plane. Thereby, the quality of a wafer edge part etc. can be maintained and a ring-shaped member (retainer ring) can be maintained in an optimal shape.
[0015]
In the present invention, it is preferable that the inclination adjusting means can be adjusted so that the inner peripheral side of the lower surface of the ring-shaped member is positioned below the outer peripheral side. Moreover, in this invention, it is preferable that it can adjust so that the outer peripheral side of the said ring-shaped member lower surface may be located below an inner peripheral side with the said inclination adjustment means. In this way, if the inclination adjusting means can positively incline the inner peripheral side and the outer peripheral side of the lower surface of the ring-shaped member (retainer ring), even if some variation occurs due to wear during processing, etc. This is because the burden on maintenance and quality control can be reduced.
[0016]
In the present invention, the ring-shaped member includes a ring-shaped member main body, and a lower ring fixed to the lower side of the ring-shaped member main body and having a lower surface abutting against the polishing pad. It is preferable that the interval between the main member and the lower ring is variable by the tilt adjusting means. This is because if the ring-shaped member (retainer ring) having such a configuration is used and the inclination adjusting means having such a configuration is employed, the intended effect of the present invention can be suitably obtained.
[0017]
In the present invention, it is preferable that the tilt adjusting means is a screw mechanism that connects the ring-shaped member main body and the lower ring. In the present invention, it is preferable that a plurality of the tilt adjusting means are arranged in the circumferential direction. With such a configuration, it is possible to delicately control the inclination of the lower surface of the ring-shaped member (retainer ring) with respect to the horizontal plane, and the object of the present invention can be achieved more reliably.
[0018]
Moreover, in this invention, it is preferable that the said lower ring is detachable with respect to the said ring-shaped member main body. Thus, if the lower ring of the ring-shaped member can be easily attached and detached, the burden of replacement work and the like can be greatly reduced.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a workpiece holding head and a polishing apparatus having the workpiece holding head according to the present invention will be described in detail with reference to the accompanying drawings.
[0020]
FIG. 1 is a perspective view showing the overall configuration of the polishing apparatus 10. As shown in the figure, the polishing apparatus 10 is mainly composed of a polishing surface plate 12 and a holding head (work holding head) 14.
[0021]
The polishing surface plate 12 is formed in a disk shape, and a rotating shaft 16 is connected to the center of the lower surface thereof. The polishing surface plate 12 rotates by driving a motor 18 connected to the rotating shaft 16. A polishing pad 20 is attached to the upper surface of the polishing surface plate 12, and abrasive slurry is supplied onto the polishing pad 20 from a nozzle (not shown).
[0022]
As shown in FIG. 2, the work holding head 14 is mainly composed of a main body (head main body) 22 of the holding head, a carrier 24, a carrier pressing means 26, a retainer ring 28 (corresponding to a lower ring), a retainer ring pressing means 30, and a protection. It comprises a seat 52, air control means, and the like.
[0023]
The head body 22 is formed in a disk shape, and a rotary shaft 32 is connected to the center of the upper surface thereof. The head main body 22 rotates by being driven by a motor (not shown) connected to the rotary shaft 32.
[0024]
The carrier 24 is formed in a disc shape and is arranged at the lower center of the head body 22. A cylindrical recess 34 is formed at the center of the upper surface of the carrier 24. A shaft portion 36 of the head body 22 is fitted into the recess 34 via a pin 38. The rotation is transmitted to the carrier 24 from the head main body 22 through the pin 38.
[0025]
Further, a carrier pressing member 40 is provided on the peripheral edge of the upper surface of the carrier 24. The carrier 24 receives a pressing force from the carrier pressing means 26 via the carrier pressing member 40.
[0026]
An air suction / blowout groove 42, which is an air supply path for injecting air to the protective sheet 52, is formed on the lower surface of the carrier 24. An air flow path 44 formed inside the carrier 24 is communicated with the suction / blowout groove 42. An intake pump and an air supply pump are connected to the air flow path 44 via an air pipe (not shown). The suction and blowing of air from the suction / blowing groove 42 is performed by switching between the intake pump and the air supply pump.
[0027]
The air suction / blowout groove 42, the air flow path 44, the air piping, the intake pump, the air supply pump, the switching means between the intake pump and the air supply pump, and the like constitute an air control means.
[0028]
The carrier pressing means 26 is disposed on the outer peripheral portion of the lower surface of the head body 22, and applies a pressing force to the carrier pressing member 40 to transmit the pressing force to the carrier 24 coupled thereto. The carrier pressing means 26 is preferably composed of a rubber sheet airbag 46 that expands and contracts by air intake and exhaust. An air supply mechanism 48 for supplying air is connected to the airbag 46, and the air supply mechanism 48 is provided with a regulator (not shown) that adjusts the pressure of air pumped from a pump (not shown).
[0029]
The retainer ring 28 is formed in a ring shape and is disposed on the outer periphery of the carrier 24. The retainer ring 28 is attached to a holder (retainer ring holder) 50 which is a ring-shaped member main body provided on the work holding head 14, and a protective sheet 52 is stretched around the inner periphery thereof.
[0030]
The retainer ring holder 50 which is a ring-shaped member main body is formed in a ring shape, and an annular recess 54 is formed on the lower surface thereof as shown in FIGS. On the other hand, a convex portion 56 that fits into the concave portion 54 is formed on the upper surface of the retainer ring 28. By fitting the convex portion 56 into the concave portion 54 of the retainer ring holder 50, the retainer ring 28 is retained by the retainer ring 28. Attached to the ring holder 50.
[0031]
As the material of the retainer ring holder 50, various metal materials can be used. In particular, stainless steel, anodized aluminum, and the like can be preferably used from the viewpoints of corrosion resistance to an abrasive and rust prevention effect.
[0032]
The material of the retainer ring 28 is preferably a material that has a wear resistance of a predetermined level or more that does not cause a problem even when mixed with an abrasive, considering that the retainer ring 28 is worn by the polishing pad 20. As a resin material such as resin, PET, polyethylene, polypropylene, PFA, PTFE and the like can be used, and as a resin material such as polyimide resin, PEEK, Vespel (trade name) and the like can be used. Of these, PEEK can be preferably used.
[0033]
The protective sheet 52 is formed in a circular shape and has a plurality of holes 52A. The protective sheet 52 is stretched inside the retainer ring 28 by sandwiching the peripheral edge portion between the retainer ring 28 and the retainer ring holder 50. That is, the protective sheet 52 is formed in a thin disk shape, and when the retainer ring 28 is attached, the peripheral portion thereof is sandwiched between the convex portion 56 of the retainer ring 28 and the concave portion 54 of the retainer ring holder 50. It is stretched inside the retainer ring 28. By stretching in this way, the protective sheet 52 is pulled in the outer circumferential direction at the same time as being attached, and is stretched uniformly over the entire surface.
[0034]
The protective sheet 52 has a plurality of holes (not shown) through which bolts 58, 58,. Similarly, the protective sheet 52 has a plurality of holes (not shown) through which adjustment bolts (male screw members) 84, 84,.
[0035]
The air ejected by the suction / blowing groove 42 of the carrier 24 forms an air layer between the carrier 24 and the protective sheet 52 by the pressing force applied by the carrier pressing means 26, and the principle of a so-called hydrostatic bearing ( The wafer W is pressed against the polishing pad 20 through the protective sheet 52 by the principle of the air bearing.
[0036]
The protective sheet 52 is an elastic member that is flexible enough to transmit the air dynamic pressure distribution formed by the air layer formed by the suction / blowout grooves 42 of the carrier 24 to the wafer W, and damages the wafer W. Therefore, it is required that the material does not contaminate.
[0037]
Further, when the retainer ring 28 is worn, it is necessary to have flexibility that can change the amount of deflection following the retainer ring 28 and sufficient strength against contact and friction with the wafer W during polishing.
[0038]
When the strength of the protective sheet 52 is insufficient, the protective sheet 52 is damaged or wrinkles occur in the protective sheet 52, and normal polishing work becomes difficult. On the other hand, if the strength of the protective sheet 52 is too high, the flexibility is insufficient, and the retainer ring 28 cannot be followed when worn. As a result, the replacement frequency of the retainer ring 28 increases.
[0039]
There are two types of wafers W, a notch type and an orientation flat type. In the case of the orientation flat type, the hardness of the protective sheet 52 is preferably high in order to reduce the influence of the orientation flat portion.
[0040]
On the other hand, in the case of the notch type, the hardness of the protective sheet 52 is preferably low as long as it has sufficient strength to withstand friction with the wafer W during polishing. That is, if the protection sheet 52 is highly flexible, the attachment position of the protection sheet 52 to the retainer ring 28 can be sufficiently higher than the upper surface of the wafer W. Thereby, even if the wear amount of the retainer ring 28 is large, the retainer ring 28 can be used, and the replacement frequency of the retainer ring 28 can be reduced.
[0041]
In order to optimize the strength of the protective sheet 52, it is necessary to treat as follows. When the hardness of the protective sheet 52 is constant, when the pressing force of the wafer W is high, the thickness of the protective sheet 52 is increased to cope with the damage of the protective sheet 52 and the generation of wrinkles of the protective sheet 52. When the pressing force of the wafer W is low, the thickness of the protective sheet 52 is reduced so that the retainer ring 28 can follow the wear.
[0042]
On the other hand, when the thickness of the protective sheet 52 is constant, when the pressing force of the wafer W is high, the hardness of the protective sheet 52 is increased so that the protective sheet 52 is damaged and wrinkles of the protective sheet 52 occur. In response, when the pressing force of the wafer W is low, the hardness of the protective sheet 52 is lowered so that the retainer ring 28 can follow the wear.
[0043]
Considering the relationship between the protective sheet 52 and the polishing pad 20, when the polishing pad 20 is soft and the pressing force of the wafer W is high, the hardness of the protective sheet 52 should be reduced and the thickness of the protective sheet 52 should be increased. It is. However, even in this case, in the case of the orientation flat type, the hardness of the protective sheet 52 should be increased and the thickness of the protective sheet 52 should be decreased to ensure elasticity.
[0044]
On the other hand, when the polishing pad 20 is hard and the pressing force of the wafer W is low, the hardness of the protective sheet 52 should be lowered and the thickness of the protective sheet 52 should be reduced. Thereby, it can press to the outer peripheral part of the wafer W, there is little uneven tension of the protection sheet 52, and the impact force added to the edge of the wafer W is also small. However, even in this case, in the case of the orientation flat type, the protective sheet 52 having a high hardness that does not easily affect the orientation flat portion should be used.
[0045]
In order to cope with this, the hardness of the protective sheet 52 needs to be within an appropriate range. If the hardness of the protective sheet 52 is too high, there is a high possibility that the back surface of the wafer W will be damaged, and the function as the protective sheet cannot be exhibited. On the other hand, if the hardness of the protective sheet 52 is too low, the protective sheet 52 is wrinkled, the amount of polishing varies partially, and normal polishing work becomes difficult.
[0046]
The thickness of the protective sheet 52 is preferably 0.1 to 2 mm. If the thickness of the protective sheet 52 exceeds 2 mm, the radius of curvature of the protective sheet 52 increases in the vicinity of the outer peripheral portion of the wafer W, and the outer peripheral portion of the wafer W cannot be polished with an appropriate pressing force, making normal polishing work difficult. It becomes.
[0047]
On the other hand, if the thickness of the protective sheet 52 is less than 0.1 mm, in order to maintain the strength of the protective sheet 52, the JIS-A hardness of the protective sheet 52 must be increased. The possibility of scratching is increased, and the function as a protective sheet cannot be exhibited.
[0048]
In particular, since the strength of rubber-based materials is low, the thickness is increased to maintain the strength. However, when the thickness of the protective sheet 52 exceeds 2 mm, the radius of curvature of the protective sheet 52 increases and the curvature increases. The center also moves outward. Therefore, the outer peripheral portion of the wafer W cannot be polished with an appropriate pressing force, and normal polishing work becomes difficult.
[0049]
In addition, with a polyimide-based material, the polishing operation can be performed even if the thickness of the protective sheet 52 is less than 0.1 mm, but even a slight scratch on the protective sheet 52 is easily broken, which is not preferable.
[0050]
Usually, the pressure of the wafer W is in the range of 20 to 70 kPa. For example, when a wafer W having an outer shape of 300 mm is polished with a pressing force of 70 kPa, a protective sheet 52 having a JIS-A hardness of 90 and a thickness of 1 mm can be used.
[0051]
As a material of the protective sheet 52, chloroprene rubber, nitrile rubber, etc. are used as rubber materials, and PET, polyethylene, polypropylene, PFA, PTFE, etc. are polyimide resins as resin materials such as tetrafluoroethylene resin. As a resin material such as PEEK, Vespel (trade name) or the like can be used.
[0052]
The retainer ring 28 is fixed to the retainer ring holder 50 by fitting the convex portion 56 into the concave portion 54 of the retainer ring holder 50 and then screwing it with bolts 58, 58. Therefore, screw holes 60, 60,... Are formed in the retainer ring 28 at regular intervals, and through holes 62, 62,... Are formed in the retainer ring holder 50 at regular intervals.
[0053]
Further, the convex portion 56 formed on the retainer ring 28 and the concave portion 54 formed on the retainer ring holder 50 have inner circumferential wall surfaces 54A and 56A formed in a tapered shape (having a tapered portion). Thus, the fitting operation can be easily performed.
[0054]
As shown in FIG. 2, an air layer is formed between the carrier 24 and the protective sheet 52 under the carrier 24 on which the protective sheet 52 is stretched. The wafer W is pressed against the carrier 24 through the air reservoir 74. The air reservoir 74 is increased in internal pressure by blowing air from the suction / blowing groove 42 of the carrier 24. The holes 52A formed in the protective sheet 52 act as suction holes when the wafer W is held and transported, and act as air ejection holes during polishing.
[0055]
The retainer ring holder 50 is attached to an attachment member 64 formed in a ring shape via a snap ring 66. The snap ring 66 is formed in a ring shape, and a groove 66A is formed on the inner periphery thereof as shown in FIG. The snap ring 66 is cut and formed so that it can be expanded and contracted. The retainer ring holder 50 and the mounting member 64 are integrated with each other by fitting the outer peripheral flange portions 50A and 64A formed on the outer periphery of the upper end portion and the outer periphery of the lower end portion into the groove 66A formed in the snap ring 66. Fixed.
[0056]
An inner peripheral flange portion 50B is formed on the inner peripheral portion of the retainer ring holder 50, and a flange portion 24A formed on the outer peripheral portion of the carrier 24 is loosely inserted into the inner peripheral flange portion 50B. Thereby, an air layer is formed between the carrier 24 and the protective sheet 52.
[0057]
The retainer ring pressing member 68 of FIG. 2 is connected to the mounting member 64. The retainer ring 28 is transmitted with a pressing force from the retainer ring pressing means 30 via the retainer ring pressing member 68.
[0058]
The retainer ring pressing means 30 is disposed on the peripheral edge of the central portion of the lower surface of the head main body 22, and applies a pressing force to the retainer ring pressing member 68 to press the retainer ring 28 coupled thereto against the polishing pad 20. The retainer ring pressing means 30 is also preferably formed of a rubber sheet airbag 70 in the same manner as the carrier pressing means 26. An air supply mechanism 72 for supplying air is connected to the airbag 70, and the air supply mechanism 72 is provided with a regulator (not shown) that adjusts the pressure of air pumped from a pump (not shown).
[0059]
Next, the inclination adjusting means 80 which is a characteristic part of the present invention will be described. As shown in FIGS. 3 and 4 described above, the inclination adjusting means 80 is provided in the retainer (the retainer ring holder 50 which is a ring-shaped member main body and the retainer ring 28 which is a lower ring). 50, a adjusting bolt 84 that is screwed into the screw hole 82, a contact plate 86 that is fitted to the upper surface of the retainer ring 28 and contacts the tip of the adjusting bolt 84, and the like. Composed. FIG. 4 is a main part plan view showing a planar arrangement of the inclination adjusting means 80.
[0060]
As shown in FIGS. 3 and 4, the inclination adjusting means 80 is provided on the inner peripheral side of the bolt 58 that fixes the retainer ring holder 50 and the retainer ring 28. When the adjustment bolt 84 is screwed into the screw hole 82 in the state of FIG. 3, the tip of the adjustment bolt 84 presses the upper surface of the retainer ring 28 via the contact plate 86. Thereby, the retainer ring 28 is elastically deformed so that the inner peripheral side of the lower surface of the retainer ring 28 is positioned below the outer peripheral side. The height difference between the inner peripheral edge and the outer peripheral edge of the lower surface of the retainer ring 28 can be set to 0.1 mm, for example.
[0061]
The reason why the abutting plate 86 is fitted on the upper surface of the retainer ring 28 is that the retainer ring 28 is generally formed of a material having a low longitudinal elastic modulus (for example, PEEK). This is to avoid local deformation of the portion where the tip of the bolt 84 abuts. For the backing plate 86, for example, stainless steel can be preferably used.
[0062]
In order for the above configuration to be effective, it is preferable that the inclination adjusting means 80 be arranged at equal intervals in the circumferential direction as shown in FIG. And in each inclination adjustment means 80, it is preferable to adjust so that the tightening amount of the adjustment bolt 84 may become uniform. In addition, as shown in FIG. 4, the inclination adjusting unit 80 may not be in a one-to-one correspondence with the bolts 58, and may be arranged more densely than the bolts 58.
[0063]
Unlike the inclination adjusting means 80 described above, an inclination adjusting means 81 is provided on the outer peripheral side of the bolt 58 that fixes the retainer ring holder 50 and the retainer ring 28, as indicated by an imaginary line in FIG. It is also possible to adopt a configuration that has In this case, the tip of the adjustment bolt 84 presses the upper surface of the retainer ring 28 via the contact plate 86, and thereby the retainer ring 28 is positioned so that the outer peripheral side of the lower surface of the retainer ring 28 is positioned below the inner peripheral side. Elastically deforms. The height difference between the inner peripheral edge and the outer peripheral edge of the lower surface of the retainer ring 28 can be set to 0.1 mm, for example. When the above-described inclination adjusting means 80 (or inclination adjusting means 81) is employed and machining is continuously performed for a long time, the lower surface of the retainer ring 28 may be worn and become horizontal. In that case, the adjustment bolt 84 may be further tightened, and the retainer ring 28 may be elastically deformed into a preferred shape.
[0064]
The wafer polishing method of the polishing apparatus 10 configured as described above is as follows.
[0065]
First, the wafer W is held by the work holding head 14 and placed on the polishing pad 20. At this time, the wafer W is sucked and held by using the sucking / blowing grooves 42 formed on the lower surface of the carrier 24. For this suction, the protective sheet 52 has a plurality of holes 52A (see FIG. 3). The wafer W is sucked and held through the hole 52A.
[0066]
Next, air is supplied to the airbags 46 and 70 from a pump (not shown). At the same time, air is blown out from the suction / blowing groove 42 of the carrier 24. As a result, the internal pressure of the air reservoir 74 is increased and the airbags 46 and 70 are inflated, and the wafer W and the retainer ring 28 are pressed against the polishing pad 20 with a predetermined pressure. In this state, the polishing surface plate 12 is rotated in the direction of FIG. 1A, and the work holding head 14 is rotated in the direction of FIG. 1B. Then, slurry is supplied onto the rotating polishing pad 20 from a nozzle (not shown). Thereby, the lower surface of the wafer W is polished by the polishing pad 20.
[0067]
Since the protective sheet 52 has a plurality of holes 52A (see FIG. 3), the air supplied to the air reservoir 74 presses the back surface of the wafer W through the protective sheet 52 from the holes 52A. To do. No direct pressing force acts between the protective sheet 52 present in the air layer and the back surface of the wafer W. Therefore, the thickness unevenness of the protective sheet 52 does not affect the processing accuracy of the wafer W.
[0068]
In addition, since the protective sheet 52 has a plurality of holes 52A for suction, a thin air layer is formed between the protective sheet 52 and the back surface of the wafer W. There is almost no air flow, and even if there is an air flow, the amount of air is so small that the slurry does not aggregate.
[0069]
Thus, according to the polishing apparatus 10 of the present embodiment, by providing the tilt adjusting means that can adjust the tilt of the lower surface of the retainer ring with respect to the horizontal plane, the quality of the wafer edge portion and the like can be maintained, and The retainer ring can be maintained in an optimal shape.
[0070]
Further, in the polishing apparatus 10 of the present embodiment, since the convex portion 56 is formed on the upper surface of the retainer ring 28, the strength and durability of the retainer ring can be improved.
[0071]
In this embodiment, the retainer ring 28 holding the protective sheet 52 and the retainer ring holder 50 are fixed by the bolts 58, but they may be fixed by bonding with an adhesive.
[0072]
As mentioned above, although the example of embodiment of the substrate polishing apparatus which concerns on this invention was demonstrated, this invention is not limited to the example of the said embodiment, Various aspects can be taken.
[0073]
For example, in the example of the embodiment, the carrier 24 is arranged above the protective sheet 52 and the wafer W is pressed using air pressure. However, the carrier 24 is physically brought into contact with the protective sheet 52. It can also be configured to press the wafer W.
[0074]
In the example of the embodiment, the tilt adjusting means 80 is configured by a combination of a screw hole 82 (female screw) and an adjustment bolt 84 (male screw), but other screw mechanisms such as a differential screw are employed. You can also
[0075]
Alternatively, a configuration may be adopted in which a large number of the retainer ring 28 having the protective sheet 52 bonded and fixed thereto are prepared and attached to the retainer ring holder 50 with one touch. In this case, a thrust force in the circumferential direction is applied between the retainer ring 28 and the retainer ring holder 50, but the force to be separated in the vertical direction hardly acts. A structure that can transmit a thrust force in the circumferential direction can be adopted, and a configuration in which vertical fixing is performed with a simple pin member or the like can be adopted.
[0076]
【The invention's effect】
As described above, according to the present invention, the ring-shaped member, that is, the tilt adjusting means that can adjust the tilt of the lower surface of the retainer ring with respect to the horizontal plane is provided, or the lower surface of the retainer ring is tilted with respect to the horizontal plane. Thereby, the quality of a wafer edge part etc. can be maintained and a ring-shaped member (retainer ring) can be maintained in an optimal shape.
[Brief description of the drawings]
FIG. 1 is a perspective view showing the overall structure of a substrate polishing apparatus.
FIG. 2 is a longitudinal sectional view showing a configuration of a work holding head.
FIG. 3 is a cross-sectional view showing a configuration of a holding portion of a protective sheet
FIG. 4 is a main part plan view showing a planar arrangement of the tilt adjusting means.
FIG. 5 is a front view showing a configuration of a main part of a conventional wafer holding head.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Polishing apparatus, 12 ... Polishing surface plate, 14 ... Work holding head, 20 ... Polishing pad, 24 ... Carrier, 28 ... Retainer ring (lower ring), 42 ... Suction / blowing groove, 44 ... Air flow path, 46 ... Air bag 48 ... Air supply mechanism 50 ... Retainer ring holder (ring-shaped member main body) 52 ... Protective sheet 72 ... Air supply mechanism 74 ... Air reservoir 80 ... Tilt adjusting means 82 ... Screw hole (female screw) Member), 84 ... adjustment bolt (male screw member), 86 ... backing plate, W ... wafer

Claims (10)

A carrier that holds the workpiece and presses the surface of the workpiece against the polishing pad;
A workpiece holding head comprising: a ring-shaped member disposed on an outer periphery of the carrier and surrounding the workpiece and abutting against the polishing pad;
A work holding head, wherein a lower surface of the ring-shaped member is inclined with respect to a horizontal plane. A carrier that holds the workpiece and presses the surface of the workpiece against the polishing pad;
A workpiece holding head comprising: a ring-shaped member disposed on an outer periphery of the carrier and surrounding the workpiece and abutting against the polishing pad;
The workpiece holding head, wherein the ring-shaped member is provided with an inclination adjusting means capable of adjusting an inclination of a lower surface of the ring-shaped member with respect to a horizontal plane. A protective sheet made of an elastic material that presses the workpiece against the polishing pad;
A ring-shaped member that holds the periphery of the protective sheet and is in contact with the polishing pad;
In a work holding head comprising a carrier that presses a protective sheet corresponding to a work area toward the work,
The workpiece holding head, wherein the ring-shaped member is provided with an inclination adjusting means capable of adjusting an inclination of a lower surface of the ring-shaped member with respect to a horizontal plane. 4. The work holding head according to claim 2, wherein the tilt adjusting means can adjust the inner peripheral side of the lower surface of the ring-shaped member to be positioned below the outer peripheral side. 5. 4. The work holding head according to claim 2, wherein the tilt adjusting means can adjust the outer peripheral side of the lower surface of the ring-shaped member to be positioned below the inner peripheral side. 5. The ring-shaped member is composed of a ring-shaped member main body, and a lower ring fixed to the lower side of the ring-shaped member main body and having a lower surface abutted against the polishing pad,
The work holding head according to any one of claims 2 to 5, wherein an interval between the ring-shaped member main body and the lower ring is variable by the inclination adjusting means. The work holding head according to claim 6, wherein the inclination adjusting unit includes a screw mechanism that connects the ring-shaped member main body and the lower ring. The work holding head according to claim 2, wherein a plurality of the tilt adjusting means are arranged in a circumferential direction. The work holding head according to any one of claims 6 to 8, wherein the lower ring is detachable from the ring-shaped member main body. A polishing apparatus comprising the work holding head according to claim 1.

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