JP2003173995A - Substrate holding device and polishing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate holding device which can polish in correspondence to a film thickness distribution of a thin film formed on a surface of an object to be polished such as a semiconductor wafer or the like and can obtain uniformity of the film thickness after polished, and to provide a polishing device. <P>SOLUTION: A substrate holding device holds a semiconductor wafer W as an object to be polished and presses it to a polishing surface. The substrate holding device comprises a top ring main body 2 internally having an accommodating space and a chucking plate 6 vertically movable in the accommodating space of the top ring main body 2. A ring tube 9 formed with an elastic film 91 so as to abut against directly or indirectly the semiconductor wafer W is fit on a lower surface of the chucking plate 6, and the chucking plate 6 is formed with a material having high rigidity. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate holding device for holding a substrate which is an object to be polished and pressing it against a polishing surface, and more particularly to a polishing device for polishing and flattening a substrate such as a semiconductor wafer. The present invention relates to a substrate holding device that holds a substrate. The present invention also relates to a polishing apparatus including such a substrate holding device.

[0002]

2. Description of the Related Art In recent years, as semiconductor devices have become more and more miniaturized and the element structure has become more complicated, and the number of layers of logic-based multilayer wiring has increased, the unevenness of the surface of semiconductor devices has increased more and more Tends to become. This is because in the manufacture of a semiconductor device, a step of forming a thin film, performing fine processing such as patterning and opening, and then forming a next thin film is repeated many times.

When unevenness on the surface of a semiconductor device increases,
When the thin film is formed, the film thickness at the stepped portion becomes thin, or an open due to a disconnection of the wiring or a short circuit due to insulation failure between the wiring layers occurs, so that there is a tendency that a non-defective product cannot be obtained or the yield is reduced. Further, even if the device normally operates normally in the initial stage, there arises a problem of reliability when used for a long time. Furthermore, during the exposure in the lithography process, if the irradiation surface has irregularities, the lens focus of the exposure system cannot be partially adjusted, so that if the irregularities on the surface of the semiconductor device increase, it becomes difficult to form the fine pattern itself.

Therefore, in the manufacturing process of semiconductor devices, the technique of planarizing the surface of semiconductor devices is becoming more and more important. The most important of these planarization technologies is chemical mechanical polishing (CMP).
Polishing)). In this chemical mechanical polishing, a polishing apparatus is used to supply a polishing liquid containing abrasive grains such as silica (SiO ₂ ) onto a polishing surface such as a polishing pad while sliding a substrate such as a semiconductor wafer onto the polishing surface. It is brought into contact with and polished.

This type of polishing apparatus comprises a polishing table having a polishing surface composed of a polishing pad, and a substrate holding device called a top ring or a carrier head for holding a semiconductor wafer. When polishing a semiconductor wafer using such a polishing apparatus, the semiconductor wafer is held by the substrate holding apparatus while being pressed against the polishing table with a predetermined pressure. At this time, by relatively moving the polishing table and the substrate holding device, the semiconductor wafer is brought into sliding contact with the polishing surface, and the surface of the semiconductor wafer is polished flat and mirror-finished.

In such a polishing apparatus, when the relative pressing force between the semiconductor wafer being polished and the polishing surface of the polishing pad is not uniform over the entire surface of the semiconductor wafer, each portion of the semiconductor wafer is Under-polishing or over-polishing occurs depending on the pressing force applied. Therefore, the holding surface of the semiconductor wafer of the substrate holding device is formed of an elastic film made of an elastic material such as rubber, a fluid pressure such as air pressure is applied to the back surface of the elastic film, and the pressing force applied to the semiconductor wafer is applied over the entire surface. It is also being made uniform.

Further, since the polishing pad has elasticity, the pressing force applied to the outer peripheral edge portion of the semiconductor wafer being polished becomes non-uniform, so that only the outer peripheral edge portion of the semiconductor wafer is polished a lot, that is, so-called "rimming". May occur. In order to prevent such edging, a substrate having a structure in which the outer peripheral edge of the semiconductor wafer is held by a guide ring or a retainer ring and the polishing surface located on the outer peripheral edge side of the semiconductor wafer is pressed by the guide ring or the retainer ring Holding devices have also been used.

[0008]

By the way, the thin film formed on the surface of the semiconductor wafer has a different film thickness depending on the radial position of the semiconductor wafer due to the characteristics of the method and apparatus used for film formation. That is, it has a film thickness distribution in the radial direction.
Therefore, in the conventional substrate holding apparatus that uniformly presses and polishes the entire surface of the semiconductor wafer as described above, the entire surface of the semiconductor wafer is uniformly polished. It is not possible to obtain the same polishing amount distribution as. Therefore, the conventional polishing apparatus cannot sufficiently deal with the film thickness distribution in the radial direction, which causes insufficient polishing or overpolishing.

The film thickness distribution on the surface of the semiconductor wafer described above also differs depending on the film forming method and the type of film forming apparatus. That is, the radial position and the number of thick portions,
Further, the difference in film thickness between the thin film portion and the thick film portion differs depending on the film forming method and the type of film forming apparatus. Therefore, there is a demand for a substrate holding device that can deal with various film thickness distributions easily and at low cost, instead of a substrate holding device that supports only a certain film thickness distribution.

The present invention has been made in view of the above problems of the prior art, and polishing can be performed corresponding to the film thickness distribution of a thin film formed on the surface of an object to be polished such as a semiconductor wafer. It is an object of the present invention to provide a substrate holding device and a polishing device that can achieve uniform film thickness after polishing.

[0011]

In order to solve the problems in the prior art, the first aspect of the present invention is
A substrate holding device for holding a substrate that is an object to be polished and pressing it against a polishing surface is provided with a top ring main body having an accommodation space inside, and a vertical movement member movable up and down in the accommodation space of the top ring main body. A substrate provided with an abutting member having an elastic film that directly or indirectly abuts the substrate on the lower surface of the vertically moving member, and the vertically moving member is formed of a material having high rigidity. It is a holding device.

With such a structure, the vertical moving member is made of a highly rigid and lightweight material such as epoxy resin, so that the vertical moving member is less likely to bend and the polishing rate is locally increased. Can be prevented. If a material that does not have magnetism is selected for the vertical movement member, the thickness of the thin film formed on the surface of the substrate to be polished can be measured by the film thickness measurement method using eddy current while holding the substrate to be polished. Will also be possible.

A second aspect of the present invention is a substrate holding device for holding a substrate which is an object to be polished and pressing it against a polishing surface, wherein a contact member having an elastic film is attached to the lower surface of the top ring, The elastic film of the abutting member has an abutting portion that has an outwardly projecting collar and that directly or indirectly abuts the substrate, and the top ring that extends upward from the base of the collar of the abutting portion. And a connection portion connected to the top ring, and the top ring is provided with a support portion for supporting the brim of the contact member.

With such a structure, it is possible to polish the entire surface of the substrate without depending on the film thickness distribution at the time of film formation, and at the same time, the pressurized fluid is provided in the space around the contact member. When supplied, the collar is prevented from being deformed and sticking to the lower surface of the top ring, and stable polishing can be realized.

In this case, it is preferable that the radial length of the support portion is longer than the radial length of the collar of the contact member. By providing such a supporting portion, the brim of the abutting member can be supported more reliably, so that more stable polishing can be realized.

A preferred aspect of the present invention is characterized in that a fluid introduction groove for introducing a fluid is formed in the upper surface of the brim of the contact member in the support portion. With such a configuration, the pressurized fluid can be supplied to the upper surface of the collar, so that the adhesion of the collar to the substrate can be improved and stable polishing can be realized.

According to a third aspect of the present invention, in a substrate holding device for holding a substrate which is an object to be polished and pressing it against a polishing surface, a top ring body having a containing space therein, and a containing space of the top ring body. An up-down moving member that can move up and down inside and a seal ring that abuts on the upper surface of the outer peripheral edge portion of the substrate are provided, and the up-down moving member has a radial length of 1 mm to 7 mm that supports the seal ring. The substrate holding device is characterized in that a supporting portion is provided.

With this structure, the entire surface of the substrate can be polished properly without depending on the film thickness distribution during film formation, and the pressurized fluid is supplied to the space near the seal ring. It is possible to prevent the seal ring from being deformed and sticking to the lower surface of the vertical movement member. Although the outer peripheral portion of the substrate tends to be over-polished, such over-polishing can be suppressed by setting the radial length of the support portion of the vertical movement member to 1 mm to 7 mm.

A preferred aspect of the present invention is characterized in that a fluid introduction groove for introducing a fluid to the upper surface of the seal ring is formed in the support portion of the vertical movement member. With such a configuration, the pressurized fluid can be supplied to the upper surface of the seal ring, so that the adhesion of the seal ring to the substrate can be improved and stable polishing can be realized.

A fourth aspect of the present invention is a polishing apparatus including the substrate holding device described above and a polishing table having a polishing surface.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a substrate holding device according to the present invention will be described in detail below with reference to the drawings.
FIG. 1 is a cross-sectional view showing the overall structure of a polishing apparatus having a substrate holding device according to the present invention. Here, the substrate holding device is a device that holds a substrate such as a semiconductor wafer that is an object to be polished and presses it against the polishing surface on the polishing table. As shown in FIG. 1, a polishing table 100 having a polishing pad 101 attached to an upper surface thereof is installed below a top ring 1 which constitutes a substrate holding apparatus according to the present invention. A polishing liquid supply nozzle 102 is installed above the polishing table 100. The polishing liquid supply nozzle 1
02 polishing pad 101 on the polishing table 100
The polishing liquid Q is supplied on top.

There are various polishing pads available on the market, for example, SUBA manufactured by Rodel Co.
800, IC-1000, IC-1000 / SUBA4
00 (two-layer cloth), and Surfin xxx-5 and Surfin 000 manufactured by Fujimi Incorporated. SUBA800, Surfin xxx-5,
Surfin 000 is a non-woven fabric in which fibers are solidified with urethane resin, and IC-1000 is a hard polyurethane foam (single layer). The foamed polyurethane is porous and has a large number of fine dents or pores on its surface.

The top ring 1 is connected to a top ring drive shaft 11 via a universal joint portion 10. The top ring drive shaft 11 is connected to a top ring air cylinder 111 fixed to a top ring head 110. There is. The top ring drive shaft 11 is moved up and down by the top ring air cylinder 111 to raise and lower the entire top ring 1 and press the retainer ring 3 fixed to the lower end of the top ring body 2 against the polishing table 100. ing. Air cylinder for top ring 11
1 is connected to the pressure adjusting unit 120 via the regulator R1. The pressure adjusting unit 120 adjusts the pressure by supplying a pressurized fluid such as compressed air from a compressed air source or by drawing a vacuum with a pump or the like. The pressure adjusting unit 120 can adjust the air pressure of the pressurized air supplied to the top ring air cylinder 111 via the regulator R1. As a result, the retainer ring 3 becomes the polishing pad 10.
The pressing force for pressing 1 can be adjusted.

The top ring drive shaft 11 is connected to the rotary cylinder 112 via a key (not shown). The rotary cylinder 112 is provided with a timing pulley 113 on its outer peripheral portion. A top ring motor 114 is fixed to the top ring head 110, and the timing pulley 113 is the timing pulley 1 provided on the top ring motor 114 via a timing belt 115.
It is connected to 16. Therefore, by rotating the top ring motor 114, the timing pulley 1
16, the rotation belt 112 and the top ring drive shaft 1 via the timing belt 115 and the timing pulley 113.
1 rotates together, and the top ring 1 rotates. In addition,
The top ring head 110 includes a top ring head shaft 11 rotatably supported by a frame (not shown).
Supported by 7.

Hereinafter, the top ring 1 constituting the substrate holding device according to the present invention will be described in more detail. 2 is a vertical cross-sectional view showing the top ring 1 in the present embodiment, and FIG. 3 is a bottom view of the top ring 1 shown in FIG. As shown in FIG. 2, a top ring 1 that constitutes a substrate holding device.
Is provided with a cylindrical container-shaped top ring main body 2 having an accommodation space inside, and a retainer ring 3 fixed to the lower end of the top ring main body 2. The top ring body 2 is made of a material having high strength and rigidity such as metal or ceramics. Further, the retainer ring 3 is made of a highly rigid resin material or ceramics.

The top ring main body 2 has a cylindrical container-shaped housing portion 2a, an annular pressure sheet support portion 2b fitted inside the cylindrical portion of the housing portion 2a, and an outer peripheral edge portion on the upper surface of the housing portion 2a. Annular seal part 2c fitted to
It has and. Housing part 2 of top ring body 2
A retainer ring 3 is fixed to the lower end of a. The lower part of the retainer ring 3 projects inward. In addition,
The retainer ring 3 may be formed integrally with the top ring body 2.

The top ring drive shaft 11 described above is disposed above the center of the housing portion 2a of the top ring body 2, and the top ring body 2 and the top ring drive shaft 11 are connected by the universal joint portion 10. It is connected. The universal joint portion 10 includes a spherical bearing mechanism that allows the top ring body 2 and the top ring drive shaft 11 to tilt with respect to each other, and a rotation transmission mechanism that transmits the rotation of the top ring drive shaft 11 to the top ring body 2. Therefore, the pressing force and the rotational force are transmitted from the top ring drive shaft 11 to the top ring body 2 while allowing the tilting of each other.

The spherical bearing mechanism includes a top ring drive shaft 11
Spherical recess 11a formed in the center of the lower surface of the housing, and spherical recess 2d formed in the center of the upper surface of the housing 2a.
And a bearing ball 12 made of a high hardness material such as ceramics and interposed between the recesses 11a and 2d. On the other hand, the rotation transmission mechanism is composed of a drive pin (not shown) fixed to the top ring drive shaft 11 and a driven pin (not shown) fixed to the housing portion 2a. Even if the top ring body 2 is tilted, the driven pin and the driving pin can move relative to each other in the vertical direction.
These are engaged with each other by shifting their contact points, and the rotation transmission mechanism reliably transmits the rotation torque of the top ring drive shaft 11 to the top ring main body 2.

In the space defined inside the top ring main body 2 and the retainer ring 3 fixed integrally to the top ring main body 2, a seal that abuts the outer peripheral portion of the semiconductor wafer W held by the top ring 1 A ring 4, an annular holder ring 5, and a roughly disk-shaped chucking plate 6 (vertical moving member) that can move up and down in a housing space inside the top ring body 2 are housed.

The outer periphery of the seal ring 4 is sandwiched between the holder ring 5 and a chucking plate 6 fixed to the lower end of the holder ring 5, and covers the lower surface near the outer edge of the chucking plate 6. There is. The lower end surface of the seal ring 4 is in contact with the upper surface of the semiconductor wafer W, which is an object to be polished. The seal ring 4 is made of ethylene propylene rubber (EPDM), polyurethane rubber,
It is formed of a rubber material such as silicon rubber having excellent strength and durability. The outer edge of the semiconductor wafer W is provided with a notch or an orientation flat called a notch for recognizing (specifying) the orientation of the semiconductor wafer. The chucking plate 6 is more suitable than the notch or orientation flat. It is preferable that the seal ring 4 extends to the inner peripheral side of the.

A pressure sheet 7 made of an elastic film is stretched between the holder ring 5 and the top ring body 2. The pressure sheet 7 has one end sandwiched between the housing portion 2a of the top ring body 2 and the pressure sheet support portion 2b and the other end sandwiched between the upper end portion 5a of the holder ring 5 and the stopper portion 5b. It is fixed. A pressure chamber 21 is formed inside the top ring body 2 by the top ring body 2, the chucking plate 6, the holder ring 5, and the pressure sheet 7. As shown in FIG.
The pressure chamber 21 includes a fluid path 3 including a tube and a connector.
1 communicates with each other, and the pressure chamber 21 is connected to the pressure adjusting unit 120 via a regulator R2 arranged on the fluid passage 31. The pressure sheet 7 is formed of a rubber material having excellent strength and durability such as ethylene propylene rubber (EPDM), polyurethane rubber, and silicon rubber.

When the pressure sheet 7 is an elastic body such as rubber, when the pressure sheet 7 is fixed by being sandwiched between the retainer ring 3 and the top ring body 2, the pressure sheet as an elastic body. The elastic deformation of 7 makes it impossible to obtain a preferable flat surface on the lower surface of the retainer ring 3. Therefore, in order to prevent this, in the present embodiment, the pressure sheet support portion 2b is provided as a separate member, and is sandwiched between the housing portion 2a of the top ring body 2 and the pressure sheet support portion 2b and fixed. is doing. The retainer ring 3 can be vertically movable with respect to the top ring body 2, or the retainer ring 3 can be pressed independently of the top ring body 2. In such a case, The fixing method of the pressure sheet 7 described above is not always used.

On the lower surface of the seal portion 2c of the top ring body 2, a cleaning liquid passage 51 consisting of an annular groove is formed.
The cleaning liquid passage 51 communicates with the fluid passage 32 through the through hole 52, and the cleaning liquid (pure water) passes through the fluid passage 32.
Is supplied. Further, a plurality of communication holes 53 extending from the cleaning liquid passage 51 of the seal part 2c and penetrating the housing part 2a and the pressure sheet supporting part 2b are formed.
3 is communicated with a slight gap G between the outer peripheral surface of the seal ring 4 and the retainer ring 3.

At the center of the lower surface of the chucking plate 6, there is provided a center port 8 having an opening 8a formed at the center. Further, inside the space formed between the chucking plate 6 and the semiconductor wafer W, a ring tube 9 is provided as a contact member that contacts the semiconductor wafer W. In this embodiment, FIG. 2 and FIG.
As shown in, the ring tube 9 is arranged outside the center port 8 so as to surround the center port 8. Further, the chucking plate 6 is provided with suction portions 40 projecting downward, outside the ring tube 9, and in this embodiment, six suction portions 40 are provided.

The ring tube 9 is composed of an elastic film 91 that contacts the upper surface of the semiconductor wafer W, and a ring tube holder 92 that detachably holds the elastic film 91. These elastic film 91 and ring tube holder 92
A pressure chamber 22 is formed inside the ring tube 9. The space formed between the chucking plate 6 and the semiconductor wafer W is defined by the ring tube 9 described above.
Is divided into a plurality of spaces by the pressure chamber 23 inside the ring tube 9, that is, around the center port 8.
However, pressure chambers 24 are formed outside the ring tube 9, that is, around the adsorption portion 40. The elastic film 91 of the ring tube 9 is formed of a rubber material having excellent strength and durability, such as ethylene propylene rubber (EPDM), polyurethane rubber, and silicon rubber, like the pressure sheet 7.

A fluid passage 33 composed of a tube, a connector and the like is communicated with the pressure chamber 22 in the ring tube 9, and the pressure chamber 22 is provided with a pressure adjusting portion via a regulator R3 arranged on the fluid passage 33. It is connected to 120. Further, the opening 8a of the center port 8 communicates with a fluid passage 34 including a tube, a connector, etc., and the center port 8 is provided with a regulator R4 arranged on the fluid passage 34.
It is connected to the pressure adjusting unit 120 via. Adsorption part 4
0 is formed with a communication hole 40a that communicates with the fluid passage 35 including a tube, a connector, etc., and the adsorption portion 40 is connected to the pressure adjustment portion 120 via the regulator R5 arranged on this fluid passage 35. ing. This pressure adjustment unit 1
A negative pressure can be formed at the opening end of the communication hole 40a of the suction unit 40 by 20, and the semiconductor wafer W can be suctioned to the suction unit 40. An elastic sheet 40b made of a thin rubber sheet or the like is attached to the lower end surface of the suction section 40, and the suction section 40 flexibly holds the semiconductor wafer W by suction. The pressure chambers 21 to 24 are connected to the regulators R2 to R5 via a rotary joint (not shown) provided at the upper end of the top ring shaft 110.

The pressure chamber 21 above the chucking plate 6 and the pressure chambers 22, 23, 24 are pressurized air or the like via fluid passages 31, 33, 34, 35 communicating with the pressure chambers. It is possible to supply the pressurized fluid, or to make the atmospheric pressure or vacuum. That is, FIG.
, The fluid paths 31, 33 of the pressure chambers 21-24,
The pressures of the pressurized fluids supplied to the respective pressure chambers can be adjusted by the regulators R2 to R5 arranged on the valves 34 and 35. As a result, the pressure inside each of the pressure chambers 21 to 24 can be independently controlled or can be set to atmospheric pressure or vacuum. In this way, the pressure inside the pressure chambers 21 to 24 is independently made variable by the regulators R2 to R5, so that the pressing force for pressing the semiconductor wafer W against the polishing pad 101 is adjusted for each part of the semiconductor wafer W. be able to.

In this case, the pressurized fluid supplied to the pressure chambers 22 to 24 and the temperature of the atmospheric pressure may be controlled respectively. By doing so, the temperature of the polishing target can be directly controlled from the back side of the surface to be polished of the polishing target such as a semiconductor wafer. Particularly, if the temperature of each pressure chamber is controlled independently, the chemical reaction rate of chemical polishing in CMP can be controlled.

Here, since there is a slight gap G between the outer peripheral surface of the seal ring 4 and the retainer ring 3, the holder ring 5, the chucking plate 6, and the seal ring 4 attached to the chucking plate 6. Members such as are movable in the vertical direction with respect to the top ring body 2 and the retainer ring 3 and have a floating structure. The stopper portion 5b of the holder ring 5 is provided with a plurality of protrusions 5c protruding outward from its outer peripheral edge portion, and the protrusions 5c are provided on the upper surface of the portion protruding inward of the retainer ring 3. By fitting, the downward movement of the members such as the holder ring 5 is limited to a predetermined position.

For example, the chucking plate is made of PPS.
When formed of (polyphenylene sulfide), when the pressure of the pressure chamber 21 is higher than the pressure of the pressure chambers 22 to 24 below the chucking plate 6, the chucking plate bends and the suction portion 40 presses the semiconductor wafer W. Therefore, the polishing rate of this portion locally increases. Therefore, the chucking plate 6 in the present embodiment is formed of a material having higher rigidity and lighter weight than PPS, for example, epoxy resin, more preferably fiber reinforced material such as glass fiber. As described above, by forming the chucking plate 6 with a material having high rigidity, the chucking plate 6 is less likely to bend even if the pressure of the pressure chamber 21 is higher than the pressure of the pressure chambers 22 to 24 below the chucking plate 6. Therefore, it is possible to prevent the polishing rate from locally increasing. In particular, since epoxy resin does not have magnetism, the thickness of the thin film formed on the surface of the semiconductor wafer to be polished is measured by the film thickness measurement method using eddy current while the semiconductor wafer to be polished is held on the top ring. It is a suitable material in some cases. Further, it is not limited to the epoxy resin, and it is also effective to use, for example, a highly rigid resin other than the epoxy resin, its fiber reinforced material, ceramics, or the like.

Next, the operation of the top ring 1 thus constructed will be described in detail. In the polishing apparatus having the above configuration, when the semiconductor wafer W is transferred, the entire top ring 1 is positioned at the semiconductor wafer transfer position, and the communication hole 40a of the suction section 40 is connected to the pressure adjusting section 120 via the fluid path 35. . The semiconductor wafer W is vacuum-sucked to the lower end surface of the suction portion 40 by the suction action of the communication hole 40a. Then, the top ring 1 is moved in a state where the semiconductor wafer W is sucked, and the entire top ring 1 is positioned above the polishing table 100 having the polishing surface (polishing pad 101). The outer peripheral edge of the semiconductor wafer W is held by the retainer ring 3 so that the semiconductor wafer W does not protrude from the top ring 1.

At the time of polishing, the suction of the semiconductor wafer W by the suction unit 40 is released, the semiconductor wafer W is held on the lower surface of the top ring 1, and the top ring air cylinder 111 connected to the top ring drive shaft 11 is operated. Then, the retainer ring 3 fixed to the lower end of the top ring 1 is pressed against the polishing surface of the polishing table 100 with a predetermined pressing force. In this state, a pressurized fluid having a predetermined pressure is supplied to each of the pressure chambers 22, 23 and 24 to press the semiconductor wafer W against the polishing surface of the polishing table 100. Then, the polishing liquid Q is held in the polishing pad 101 by flowing the polishing liquid Q from the polishing liquid supply nozzle 102 in advance, and the semiconductor wafer W
The polishing is performed in the state where the polishing liquid Q is present between the surface (lower surface) to be polished and the polishing pad 101.

The portions of the semiconductor wafer W located below the pressure chambers 23 and 24 are pressure chambers 23 and 2, respectively.
It is pressed against the polishing surface by the pressure of the pressurized fluid supplied to No. 4.
The portion of the semiconductor wafer W located below the pressure chamber 22 is pressed against the polishing surface by the pressure of the pressurized fluid supplied to the pressure chamber 22 via the elastic film 91 of the ring tube 9. Therefore, the polishing pressure applied to the semiconductor wafer W can be adjusted for each part of the semiconductor wafer W by controlling the pressure of the pressurized fluid supplied to each of the pressure chambers 22 to 24. That is, the pressures of the pressurized fluids supplied to the pressure chambers 22 to 24 are independently adjusted by the regulators R3 to R5, and the pressing force for pressing the semiconductor wafer W against the polishing pad 101 on the polishing table 100 is adjusted. Is adjusted for each part. In this way, the semiconductor wafer W is pressed against the polishing pad 101 on the upper surface of the rotating polishing table 100 with the polishing pressure adjusted to a desired value for each portion of the semiconductor wafer W. Similarly, the regulator R1 can adjust the pressure of the pressurized fluid supplied to the top ring air cylinder 111 to change the pressing force with which the retainer ring 3 presses the polishing pad 101. As described above, during polishing, the pressing force of the retainer ring 3 pressing the polishing pad 101 and the pressing force of pressing the semiconductor wafer W to the polishing pad 101 are appropriately adjusted, so that the central portion of the semiconductor wafer W (see FIG. 3). C
1), the intermediate portion (C2), the peripheral edge portion (C3), and further, the distribution of the polishing pressure in each portion up to the outer peripheral portion of the retainer ring 3 outside the semiconductor wafer W can be set to a desired distribution.

In this way, the semiconductor wafer W can be divided into three concentric circles and annular portions (C1 to C3), and the respective portions can be pressed by independent pressing forces. The polishing rate depends on the pressing force applied to the polishing surface of the semiconductor wafer W, but since the pressing force of each part can be controlled as described above, the three parts (C1 to C) of the semiconductor wafer W can be controlled.
It becomes possible to control the polishing rate of 3) independently.
Therefore, even if the thickness of the thin film to be polished on the surface of the semiconductor wafer W has a radial distribution, insufficient polishing or overpolishing can be eliminated over the entire surface of the semiconductor wafer. That is, even when the thin film to be polished on the surface of the semiconductor wafer W has a different film thickness depending on the position of the semiconductor wafer W in the radial direction, the surface of the semiconductor wafer W among the pressure chambers 22 to 24. Of the pressure chamber located above the thick portion of the semiconductor wafer W is set higher than the pressure of other pressure chambers, or of the pressure chamber located above the thin portion of the surface of the semiconductor wafer W. By making the pressure lower than the pressure of other pressure chambers, it becomes possible to make the pressing force of the thick film portion on the polishing surface larger than the pressing force of the thin film portion on the polishing surface. The polishing rate can be selectively increased. As a result, it is possible to polish the entire surface of the semiconductor wafer W without excess or deficiency without depending on the film thickness distribution during film formation.

Edges that occur on the peripheral edge of the semiconductor wafer W can be prevented by controlling the pressing force of the retainer ring 3. Further, when there is a large change in the film thickness of the thin film to be polished at the peripheral edge of the semiconductor wafer W, the peripheral pressure of the semiconductor wafer W is increased by intentionally increasing or decreasing the pressing force of the retainer ring 3. Polishing rate can be controlled. When the pressurized fluid is supplied to each of the pressure chambers 22 to 24, the chucking plate 6 receives an upward force. Therefore, in the present embodiment, the pressure fluid is supplied to the pressure chamber 21 via the fluid passage 31. However, the chucking plate 6 is prevented from being lifted upward by the force from the pressure chambers 22 to 24.

As described above, the polishing pad 10 for the retainer ring 3 formed by the top ring air cylinder 111.
1 and the polishing pad 101 for each part of the semiconductor wafer W by the pressurized air supplied to each pressure chamber 22-24.
The semiconductor wafer W is polished by appropriately adjusting the pressing force on the semiconductor wafer W. When the polishing is completed, the semiconductor wafer W
Is again vacuum-sucked to the lower end surface of the suction unit 40. At this time, the pressure chambers 22 to press the semiconductor wafer W against the polishing surface.
By stopping the supply of the pressurized fluid to 24 and opening it to atmospheric pressure, the lower end surface of the adsorption section 40 is brought into contact with the semiconductor wafer W. Further, the pressure in the pressure chamber 21 is released to the atmospheric pressure or made negative. This is because if the pressure in the pressure chamber 21 is kept high, only the portion of the semiconductor wafer W that is in contact with the suction portion 40 is strongly pressed against the polishing surface.

After adsorbing the semiconductor wafer W as described above, the entire top ring 1 is positioned at the semiconductor wafer transfer position, and a fluid (for example, compressed air or compressed air A mixture of nitrogen and pure water) is jetted to release the semiconductor wafer W.

By the way, the polishing liquid Q used for polishing enters the small gap G between the outer peripheral surface of the seal ring 4 and the retainer ring 3, and when the polishing liquid Q is fixed, the holder ring 5, chucking plate 6,
Also, smooth vertical movement of members such as the seal ring 4 with respect to the top ring body 2 and the retainer ring 3 is hindered. Therefore, the cleaning liquid (pure water) is supplied to the cleaning liquid passage 51 through the fluid passage 32. Thereby, the plurality of communication holes 53
Pure water is further supplied above the gap G, and the pure water rinses the gap G to prevent the polishing liquid Q from sticking. It is preferable that the supply of pure water be performed before the semiconductor wafer after polishing is released and the semiconductor wafer to be polished next is adsorbed. Further, it is preferable that the retainer ring 3 be provided with a plurality of through holes 3a as shown in FIG. 2 so that all the pure water supplied until the next polishing is discharged to the outside. Further, if pressure is retained in the space 25 formed by the retainer ring 3, the holder ring 5, and the pressure sheet 7, the chucking plate 6 is prevented from rising, so that the chucking plate 6 can be smoothly moved. It is preferable that the through hole 3a is provided to raise the space 25 and the space 25 has the same pressure as the atmosphere.

As described above, according to the substrate holding apparatus of this embodiment, the pressing force on the semiconductor wafer can be controlled by controlling the pressures of the pressure chambers 22, 23, 24 independently.

Here, the ring tube 9 in this embodiment will be described in more detail. FIG. 4 is a vertical cross-sectional view showing the ring tube 9 shown in FIG. As shown in FIG. 4, the elastic film 91 of the ring tube 9 according to the present embodiment has an abutting portion 91 having a brim 91a protruding outward.
b and a connecting portion 91c connected to the chucking plate 6 via the ring tube holder 92. The connecting portion 91c extends upward from the base portion 91d of the collar 91a. Further, the lower surface of the contact portion 91b contacts the upper surface of the semiconductor wafer W.
The collar 91a, the contact portion 91b, and the connecting portion 91c are integrally formed of the same material.

As described above, when polishing a semiconductor wafer, a pressurized fluid is supplied to the pressure chambers 22 and 24 surrounding the ring tube 9. As a result, the collar 91a is brought into close contact with the semiconductor wafer W by the pressurized fluid supplied to the pressure chambers 23 and 24, respectively. For this reason,
Even if the pressure of the pressurized fluid supplied to the pressure chamber 22 inside the ring tube 9 is considerably higher than the pressure of the pressurized fluid supplied to the pressure chamber 22 inside the ring tube 9, the ring The pressurized fluid having a high ambient pressure does not flow under the tube 9. Therefore, by providing the collar 91a, the width of pressure control of each pressure chamber can be increased, and the semiconductor wafer can be pressed more stably.

A plurality of openings 91e are formed in the center of the contact portion 91b of the ring tube 9, and the pressurized fluid supplied to the pressure chamber 22 through the openings 91e is the semiconductor wafer W. Will come into direct contact with the upper surface of.
Since a pressurized fluid is supplied to the pressure chamber 22 during polishing, the abutting portion 91b of the ring tube 9 is pressed against the upper surface of the semiconductor wafer W by the pressurized fluid. Therefore, even when such an opening 91e is formed, the pressurized fluid inside the pressure chamber 22 rarely leaks to the outside. Further, when the semiconductor wafer W is released,
Since downward pressure by the pressurized fluid can be applied to the semiconductor wafer W through the opening 91e, the semiconductor wafer W can be released more smoothly.

Further, as described above, when the temperature of the pressurized fluid supplied to the pressure chamber 22 is controlled to control the temperature of the semiconductor wafer W from the back side of the surface to be polished, such an opening 91e is provided. By forming the contact portion 91b of the ring tube 9 in an area where the pressurized fluid whose temperature is controlled contacts the semiconductor wafer W, the temperature controllability of the semiconductor wafer W can be improved.
Further, when the semiconductor wafer W is released after the polishing is completed, the pressure chambers 22 are opened to the outside air through the openings 91e, so that the fluid or the like supplied to the pressure chambers 22 enters inside thereof. There is no muddy. Therefore, the stability of temperature control can be maintained even when the semiconductor wafers W are continuously polished.

As shown in FIG. 4, the chucking plate 6 is provided with a support portion 6a for supporting the collar 91a of the ring tube 9. If such a supporting portion 6a is not provided, the pressure chambers 23, 2 surrounding the ring tube 9
When the pressurized fluid is supplied to 4, the collar 91a may be deformed and stick to the lower surface of the chucking plate 6 as shown in FIG. In such a state, the pressure control of the pressure chambers 22 to 24 cannot be appropriately performed. Therefore, in the present embodiment, as described above, the chucking plate 6 is used.
And a support portion 6 for supporting the collar 91a of the ring tube 9.
By providing a, it is possible to prevent the brim 91a from sticking to the lower surface of the chucking plate 6, and to prevent the pressure chambers 22-24.
We are trying to stabilize the pressure. In this case, if the radial length of the support portion is made longer than the radial length of the collar 91a, the collar 91a can be supported more reliably.

In this case, the collar 91a of the ring tube 9 comes into contact with the supporting portion 6a of the chucking plate 6, but in order to enhance the adhesion of the collar 91a to the semiconductor wafer W, the pressure chambers 23 and 24 are provided. It is necessary to press the brim 91a by the pressurized fluid supplied.
Therefore, in the present embodiment, as shown in FIG. 6, a fluid introduction groove 6b is formed in the support portion 6a of the chucking plate 6, and the collar 91a is stably stabilized by the pressurized fluid supplied to the pressure chambers 23 and 24. By pressing, the adhesion between the collar 91a and the semiconductor wafer W is enhanced.

Similarly, for the seal ring 4,
As shown in FIG. 7, it is possible that the seal ring 4 sticks to the outer peripheral edge portion of the chucking plate 6 due to the pressurized fluid supplied to the pressure chamber 24. Therefore, in this embodiment, as shown in FIG. So that the chucking plate 6
A support portion 6c for supporting the seal ring 4 is provided on the outer peripheral edge portion of the. In this case, similarly to the support portion 6a described above, the support portion 6c is also provided with a fluid introduction groove, and the seal ring 4 is stably pressed by the pressurized fluid supplied to the pressure chamber 24. Adhesion with the wafer W can also be improved. Moreover, since the pressurized fluid can be guided to the outermost periphery of the semiconductor wafer through this groove, a uniform pressing force is realized at the outer periphery of the wafer.

When the retainer ring 3 is pressed against the polishing pad 101, the polishing pad 101 near the retainer ring 3 is pressed.
Semiconductor wafer W because it rises (rebounds)
In some cases, the polishing rate of the outer peripheral portion of the may increase locally.
In the present embodiment, by shortening the radial length d of the supporting portion 6c of the chucking plate 6 described above, it becomes possible to suppress such overpolishing in the outer peripheral portion of the semiconductor wafer W. When the influence of rebound is small, the pressing force is concentrated by reducing the length d,
By increasing the length d, the pressing force can be dispersed or the polishing rate can be changed. Specifically, a desired polishing rate can be obtained by changing the range of 1 mm to 7 mm.

In the above embodiment, the fluid paths 31, 33,
34 and 35 are provided separately, but these fluid paths are integrated, and the pressure chambers are communicated with each other.
It can be freely modified depending on the magnitude of the pressing force to be applied to the semiconductor wafer W and the position to be applied. Further, in the above-described embodiment, an example in which the ring tube 9 directly contacts the semiconductor wafer W has been described, but the embodiment is not limited to this. For example, an elastic pad may be provided between the ring tube 9 and the semiconductor wafer W. Intervening, ring tube 9
May indirectly contact the semiconductor wafer W.

In the above-described embodiment, the polishing surface is formed by the polishing pad, but the present invention is not limited to this. For example, a fixed abrasive may be used to form the polishing surface. The fixed abrasive grains are formed in a plate shape by fixing the abrasive grains in a binder. In the polishing using the fixed abrasive grains, the polishing proceeds by the abrasive grains naturally generated from the fixed abrasive grains. The fixed abrasive grains are composed of abrasive grains, a binder and pores. For example, cerium oxide (CeO ₂ ) having an average particle diameter of 0.5 μm or less is used for the abrasive grains and epoxy resin is used for the binder. Such fixed abrasive grains constitute a hard polishing surface. Further, the fixed abrasive, in addition to the plate-like ones described above,
A fixed-abrasive pad having a two-layer structure in which an elastic polishing pad is attached under a thin fixed-abrasive layer is also included. As another hard polishing surface, there is the above-mentioned IC-1000.

Although one embodiment of the present invention has been described so far, it is needless to say that the present invention is not limited to the above-mentioned embodiment and may be implemented in various different forms within the scope of the technical idea thereof.

[0061]

As described above, according to the present invention, the pressure applied to the substrate is independently controlled, and the pressing force to the polishing surface of the thick film portion is applied to the polishing surface of the thin film portion. Since it can be made larger than the pressing force, the polishing rate of that portion can be selectively increased. This makes it possible to polish the entire surface of the substrate without excess or deficiency without depending on the film thickness distribution during film formation. Further, by forming the vertical moving member with a material having high rigidity and light weight, for example, an epoxy resin, it is possible to prevent the vertical moving member from easily bending and to locally increase the polishing rate. If a material having no magnetism is selected for the vertical movement member, the thin film formed on the surface of the semiconductor wafer to be polished is held on the top ring by the film thickness measurement method using eddy current. It is suitable when measuring the thickness.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an overall configuration of a polishing device according to an embodiment of the present invention.

2 is a vertical cross-sectional view showing a substrate holding device in the polishing device of FIG.

FIG. 3 is a bottom view of the substrate holding device shown in FIG.

FIG. 4 is a vertical cross-sectional view showing a ring tube in the substrate holding device of FIG.

FIG. 5 is a vertical cross-sectional view showing a state of the ring tube when the chucking plate is not provided with a support portion.

FIG. 6 is a partial perspective view showing a support portion of the chucking plate of FIG.

FIG. 7 is a vertical cross-sectional view showing a state of a seal ring when a chucking plate is not provided with a support portion.

8 is a longitudinal sectional view showing a seal ring in the substrate holding device of FIG.

[Explanation of symbols]

1 Top ring 2 Top ring body 2a housing part 2b Pressing sheet support 2c Seal part 2d spherical recess 3 retainer ring 4 seal ring 5 holder ring 5a upper end 5b Stopper part 5c protrusion 6 Chucking plate (vertical moving member) 6a, 6c support 6b Fluid introduction groove 7 Pressure sheet 8 center ports 8a opening 9 Ring tube (contact member) 10 Universal joint 11 Top ring drive shaft 11a spherical recess 12 bearing balls 21,22,23,24 Pressure chamber 25 spaces 31, 32, 33, 34, 35 Fluid path 40 Adsorption part 40a communication hole 40b elastic sheet 51 Cleaning liquid path 52 through hole 53 communication holes 91 Elastic membrane 91a brim 91b contact part 91c connection part 91d base 91e opening 92 Ring tube holder 101 polishing pad 100 polishing table 102 polishing liquid supply nozzle 110 top ring head Air cylinder for 111 top ring 112 rotating cylinder 113,116 Timing pulley 114 Top ring motor 115 Timing Belt 117 Top Ring Head Shaft 120 Pressure adjustment unit G gap Q polishing liquid R1, R2, R3, R4, R5 regulator W semiconductor wafer

Continued front page    (72) Inventor Kunihiko Sakurai             11-1 Haneda Asahi-cho, Ota-ku, Tokyo Co., Ltd.             Inside the EBARA CORPORATION (72) Inventor Hiroshi Yoshida             11-1 Haneda Asahi-cho, Ota-ku, Tokyo Co., Ltd.             Inside the EBARA CORPORATION (72) Inventor Osamu Nabeya             11-1 Haneda Asahi-cho, Ota-ku, Tokyo Co., Ltd.             Inside the EBARA CORPORATION (72) Inventor Teruhiko Ichimura             11-1 Haneda Asahi-cho, Ota-ku, Tokyo Co., Ltd.             Inside the EBARA CORPORATION F term (reference) 3C058 AA07 AA12 AB04 CA01 CB07                       DA12                 5F031 CA02 HA12 MA22 PA30

Claims (7)

[Claims] 1. A substrate holding device for holding a substrate, which is an object to be polished, and pressing it against a polishing surface, and a top ring main body having a storage space inside, and a vertically movable top and bottom in the storage space of the top ring main body. A moving member, and a contact member having an elastic film that directly or indirectly contacts the substrate is attached to the lower surface of the vertical moving member, and the vertical moving member is formed of a highly rigid material. A substrate holding device. 2. A substrate holding device for holding a substrate, which is an object to be polished, and pressing it against a polishing surface, wherein an abutting member having an elastic film is attached to a lower surface of a top ring, and the elastic film of the abutting member is attached. An abutting portion having a flange protruding outward and directly or indirectly abutting on the substrate; and a connecting portion extending upward from the base of the flange of the abutting portion and connected to the top ring. The substrate holding device, further comprising: a support portion that supports the brim of the contact member. 3. The substrate holding device according to claim 2, wherein the radial length of the support portion is longer than the radial length of the collar of the contact member. 4. The substrate holding device according to claim 2, wherein a fluid introduction groove for introducing a fluid is formed on the upper surface of the brim of the contact member in the support portion. 5. A substrate holding device for holding a substrate, which is an object to be polished, and pressing it against a polishing surface, and a top ring body having an accommodation space inside, and a vertically movable top and bottom in the accommodation space of the top ring body. A moving member,
A seal ring that abuts on an upper surface of an outer peripheral edge portion of the substrate, wherein the vertical movement member is provided with a support portion having a radial length of 1 mm to 7 mm for supporting the seal ring. Holding device. 6. The substrate holding device according to claim 5, wherein a fluid introduction groove for introducing a fluid to the upper surface of the seal ring is formed in the support portion of the vertical movement member. 7. A polishing apparatus, comprising: the substrate holding device according to claim 1; and a polishing table having a polishing surface.