JP2002079455A - Work holding mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the flatness of a work on the whole after polishing by equalizing the working pressure during the polishing over the work. SOLUTION: This work holding mechanism for holding the work in a plane vertical to the pressing direction comprises a pressing board 13 abutted on a rear face of a central part of the work 3, a pressing base 17 abutted on a rear face of a peripheral edge part of the work, a retainer ring 21 surrounding an outer edge of the work, diaphragms 16, 20, 22 holding the pressing board 13, the pressing base 17 and the retainer ring movably in the pressing direction, and balloon-shaped elastic bodies capable of being abutted on rear faces of the pressing board, the pressing base and the retainer ring, and the work 3 is pressed to a polishing pad 28 through the pressing board 13 and the pressing base 17, and the retainer ring 21 is pressed to the polishing pad 28 by expanding elastic sheets 15, 19, 23 of the balloon-shaped elastic bodies by the pressure of the fluid supplied to space parts 100, 102, 104 of the balloon-shaped elastic bodies.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work holding mechanism for holding a work such as a semiconductor wafer, a glass substrate, and an electronic component while polishing the work while moving the work relatively to a polishing pad.

[0002]

2. Description of the Related Art In a process of forming a laminated wiring on the surface of a semiconductor wafer, it is a general practice to polish and flatten the surface of an intermediate insulating layer formed on a circuit including wiring and the like. When polishing semiconductor wafers and the like, the surface to be polished of the work (also referred to as the “surface to be polished” or “surface to be processed” or simply “surface”) must be uniformly polished, and the surface to be polished must not be scratched. In addition, it is required to improve the yield by reducing the "edge dripping" generated at the peripheral edge of the surface to be polished.

[0003] In order to satisfy these demands, for example, improvements have been made to work holding mechanisms. As one of them, there is a device for holding a substrate to be polished disclosed in JP-A-8-339979. The holding device disclosed in this publication enables the polishing to proceed uniformly even if the surface plate or polishing pad has irregularities or unevenness in the thickness of the substrate, and a mechanism for attaching and detaching the substrate to be polished and The work is simplified.

FIG. 1 shows a holding device disclosed in Japanese Patent Application Laid-Open No. H8-339979. A substrate holding device (44) for holding a substrate (43) as a work to be polished is a platen (41)
It is arranged above the polishing pad (42) adhered to. In the embodiment shown, the platen (41) is rotatable. The polishing pad (42) is generally made of an elastic material. The substrate holding device (44) is fixed to the rotating shaft (45), a disk-shaped substrate holding head (46) provided integrally with the rotating shaft (45), and the lower surface of the substrate holding head (46). An annular lip seal (47) and a retainer ring (48) fixed to the outer peripheral side of the lip seal (47). The lip seal (47) is provided on the back surface of the outer edge of the substrate to be polished (43), and forms a space (50) with the substrate (43) and the substrate holding head (46). The substrate (43) is pressed against the polishing pad (4) by the pressure of the fluid supplied to the space (50).
2) is pressed. The fluid is supplied to the space (50) from the external supply source via the fluid flow passage (49).

When the substrate (43) as a work is pressed against the polishing pad (42), pressure is applied to the substrate (43) and the polishing pad. In this specification,
This pressure is called the processing pressure.

The surface to be polished of the substrate (43) is
The retainer ring (48) is positioned by the lip seal (47) so as to have a predetermined step with the surface of the retainer ring (48) in contact with the polishing pad (42). This step is provided in order to prevent the processing pressure from becoming excessively large at the peripheral portion of the polished surface of the substrate (43).

[0007]

The substrate holding apparatus shown in FIG. 1 has the following problems. First, the surface of the retainer ring (48) in contact with the polishing pad (42) wears as the polishing process proceeds, and the step between the surface and the surface to be polished of the substrate (43) is reduced. There is. The change in the level difference causes an increase in the processing pressure at the periphery of the polished surface of the substrate (43). As a result, edge drooping occurs and the yield decreases.

In order to solve this problem, for example, the retainer ring is replaced after polishing a predetermined number of substrates to be polished or every time the processing lot of the substrate to be polished changes. As another method, a method has been adopted in which the substrate (43) and the retainer ring (48) are separately pressed against a polishing pad, thereby reducing the excess or deficiency of the polishing amount at the peripheral portion of the substrate (43). However, as compared with the size of the gap (several hundred μm) provided between the retainer ring (48) and the substrate (43), the deformation size of the polishing pad (42) which is deformed by the pressing force is much smaller (10 μm). Therefore, even if the retainer ring (48) is pressed against the polishing pad (42), the processing pressure near the periphery of the substrate (43) cannot be sufficiently affected. Therefore, this method did not sufficiently improve the flatness of the substrate (43).

Second, there is a problem that fluid leaks from the lip seal (47). If the fluid leaks, the processing pressure will not be uniform over the entire substrate (43) and therefore will not have the desired flatness. If the fluid is a gas, the gas will dry and solidify the polishing liquid to aggregate the abrasive grains,
There is also a problem that the aggregated abrasive grains cause scratches on the surface to be polished of the substrate (43). The portion where the scratch has occurred cannot be used as a product, and therefore, the scratch also causes a decrease in yield.

The leakage of the fluid is caused by the inclination and the inclination between the substantially polished surface formed by the surface of the retainer ring (48) and the surface of the substrate (43) and the contact surface of the polishing pad (42). This is caused by a large change in the relative position. Such changes in tilt and relative position can be detected by the retaining ring (48)
Are fixed to the holding head (46) and cannot move or deform themselves, while the substrate (43)
This occurs because the lip seal (47) for determining the position of the surface to be polished is an elastic body.

As described above, in the conventional polishing treatment, generation of scratches and edge run-out are not sufficiently prevented, and it has been desired to further improve the yield. The present invention has been made in view of such circumstances, while preventing the occurrence of scratches due to aggregation of abrasive grains,
It is an object to make the processing pressure uniform over the entire work and to further improve the flatness of the whole work.

[0012]

In order to solve the above problems, the present invention provides a work holding mechanism for pressing a work against a polishing pad and holding the work in a plane perpendicular to the pressing direction. One or more pressing plates in contact with at least a part of the back surface, a diaphragm for holding each pressing plate movably in the pressing direction, and a balloon-like elastic body capable of contacting the back surface of each pressing plate are provided. A work holding mechanism characterized in that at least a part of the surface of a work is pressed against a polishing pad via a pressing plate by expanding a balloon-like elastic body by pressure of a supplied fluid. That is, the work holding mechanism of the present invention is characterized in that the mechanism for pressing the work against the polishing pad is constituted by a balloon-like elastic body, a diaphragm and a pressing plate.

The work held by the work holding mechanism of the present invention is generally a plate-like body in which at least one of two surfaces is flattened by polishing. Work is
Specifically, it is a semiconductor wafer, a glass substrate, an electronic component, or the like. With respect to the work holding mechanism of the present invention, the “surface” of the member and the work that constitute the work holding mechanism is the polishing pad of the two surfaces that are parallel to the polishing surface of the polishing pad when incorporated in the work holding mechanism. Refers to the surface located on the side closer to. On the other hand, the “back surface” or “back surface” of the member and the work that constitute the work holding mechanism is far from the polishing pad among the two surfaces parallel to the polishing surface of the polishing pad when incorporated in the work holding mechanism. The surface located on the side. Therefore, the “surface” of the work corresponds to the surface to be polished.

The "balloon-like elastic body" constituting the work holding mechanism of the present invention has at least a portion made of an elastic material, has a closed space through which fluid can flow in and out, and flows into the space. It refers to a material that can be at least partially elastically deformed (eg, expanded and contracted) according to the pressure of the fluid. Here, the fluid means a gas or a liquid. The gas is, for example, air, and the liquid is, for example, water.

The balloon-like elastic body includes one having a balloon-like shape formed of a thin member (for example, a sheet) made of an elastic material. In addition, the balloon-like elastic body includes a thin-walled member (for example, a sheet) made of an elastic material formed by forming a space together with other members constituting the work holding mechanism. Only the thin member made of is elastically deformed.
Specifically, the thin member made of an elastic material constituting the balloon-shaped elastic body may be a sheet material having a thickness of 0.1 to 0.5 mm made of neoprene (registered trademark) rubber or silicon rubber or the like. preferable.

The balloon-like elastic body preferably has a structure such that the fluid flowing into the space does not substantially leak outside. Therefore, for example, when the balloon-like elastic body is constituted by a sheet made of an elastic material and another member constituting the work holding mechanism, it is preferable to attach the sheet made of the elastic material to the work holding mechanism in an airtight or liquid tight manner.

The diaphragm constituting the work holding mechanism of the present invention is a thin plate-like member which can be elastically deformed by a pressing force generated by expansion of the balloon-like elastic body. The diaphragm is preferably made of a material which has sufficient strength and corrosion resistance so as not to be damaged by repeated elastic deformation and does not become a source of chemical contamination and organic contamination to a work (eg, a semiconductor wafer). Here, “chemical pollution”
It means that heavy metal ions such as Cu, Fe, and Cr adhere to the work, and "organic contamination" means that organic substances adhere to the work. Specifically, the diaphragm has a thickness of 0.05 to 0.2 made of Hastelloy, stainless steel, or the like.
0.1-mm thick plate or neoprene rubber
It is preferably a plate (or sheet) of 0.5 mm.

In the work holding mechanism of the present invention, the diaphragm holds the pressing plate movably in the pressing direction. Specifically, the diaphragm is partially attached to the pressing plate, another part is attached to a member other than the pressing plate of the work holding mechanism, and attached to the portion attached to the pressing plate and other members. The free portion is in a free state, and the free portion is freely elastically deformed (eg, bent) as a bent portion, so that the pressing plate is displaced with respect to other members. Be placed.

Attachment of the diaphragm to the pressing plate can be performed, for example, by dividing the pressing plate into two members, sandwiching the diaphragm between the two members, and fixing with a bolt or an adhesive. Attachment of the diaphragm to members other than the pressing plate can be similarly performed. As a member other than the pressing plate, there is, for example, a holding base. The “holding base” is a basic structural member that constitutes the entire work holding head provided with the work holding mechanism of the present invention, and is a member that incorporates a pressing plate or the like. The holding base can be said to be the main body of the work holding head. For example, when the pressing plate and the diaphragm are disk-shaped, the peripheral portion of the diaphragm is attached to the holding base, for example, and the central portion is attached to the pressing plate. Becomes A member other than the pressing plate to which the diaphragm is attached may be a pressing base or a holding member described later.

In the work holding mechanism of the present invention, the balloon-like elastic body is provided so as to be in contact with the back surface of the pressing plate. That is, the balloon-like elastic body is disposed so as to be able to displace (or move) the pressing plate when inflated, and to be in contact with the back surface of the pressing plate when inflated. Therefore, the “balloon-like elastic body that can be in contact with the back surface of the pressing plate” naturally includes a balloon-like elastic body that is in contact with the back surface of the pressing plate when not inflated. The balloon-like elastic body may be arranged so as to be in contact with the back surface of the pressing plate, and may be fixed to the back surface of the pressing plate with an adhesive or the like as necessary. Alternatively, as long as the pressing plate presses the workpiece against the polishing pad when the balloon-like elastic body expands, the balloon-like elastic body may be arranged so as not to contact the back surface of the pressing plate when not expanding.

In the work holding mechanism in which the diaphragm and the balloon-like elastic body are disposed as described above, the balloon-like elastic body that can come into contact with the back surface of the pressure plate expands and the force is applied to the pressure plate in a direction to press the pressure plate against the pad. When added,
The pressing plate is displaced (or moved) in the direction toward the polishing pad
At the same time, the flexible portion of the diaphragm is elastically deformed. When the pressure of the fluid decreases and contracts after the balloon-like elastic body expands, the flexible portion of the diaphragm is elastically deformed so as to return to the original state, so that the pressing plate is displaced away from the polishing pad. Therefore, in the work holding mechanism of the present invention, the displacement of the pressing plate in the pressing direction is controlled within a range in which the flexible portion of the diaphragm is elastically deformed. In that sense, the diaphragm presses the pressing plate in the pressing direction and in the opposite direction. It is movably held in the direction. The maximum displacement of the pressing plate is determined according to the material and thickness of the diaphragm, the length of the bent portion, and the like. When the displacement amount of the pressing plate is set in advance, it is necessary to select the material and thickness of the diaphragm, the length of the bent portion, and the like in order to realize the displacement amount.

The pressing plate is flexibly held by the diaphragm. Specifically, for example, even if the work surface and the polishing surface of the polishing pad are not parallel and an inclination occurs between the two surfaces, if the flexure of the diaphragm is sufficiently long, one The two surfaces are made parallel by elastically deforming the portion differently from the other portions to correct the tilt. Further, the work holding mechanism of the present invention has a structure in which the fluid supplied into the balloon-like elastic body does not leak, and it is not necessary to consider the leakage of the fluid in the balloon-like elastic body when correcting the inclination. The tilt can be corrected in a wider range than a conventional work holding mechanism that presses the entire work. Therefore, the work holding mechanism of the present invention makes it possible to make the processing pressure uniform with higher accuracy.

When this work holding mechanism is used, the pressing plate is pushed by the fluid being supplied to the space of the balloon-like elastic body and the balloon-like elastic body expands, and the work is further pushed by the pressing plate. Then, the work is pressed against the polishing pad. As described above, the fluid is confined within the balloon-like elastic body and does not leak to the polishing surface of the polishing pad. Therefore, according to the work holding mechanism of the present invention, it is possible to prevent the processing pressure from becoming non-uniform due to the leakage of the fluid (particularly gas) as in the prior art, and to prevent the polishing liquid from drying. Agglomeration of the abrasive grains is prevented, and the occurrence of scratches is thereby suppressed.

Only one pressing plate may be provided. In that case,
It is preferable that the pressing plate is provided so as to contact substantially the entire back surface of the work. The “substantially entire surface” is, for example, a portion corresponding to a circle concentric with a work having a diameter of 9/10 or more of the diameter of the work when the work has a disk shape. Therefore, if the workpiece is a disk with a diameter of 200 mm,
Preferably, a circular portion having a diameter of 180 mm or more, more preferably a circular portion having a diameter of 190 mm or more, and still more preferably a circular portion having a diameter of about 199 mm is pressed by the work as corresponding to substantially the entire surface.

A plurality of pressing plates may be provided. In that case, the work is divided into a plurality of sections, and each section is pressed by one pressing plate. When a plurality of pressing plates are provided, each pressing plate is held by a separate diaphragm, and a balloon-like elastic body capable of contacting the back surface of each pressing plate is provided for each pressing plate. When there are a plurality of pressing plates, the pressure of the fluid supplied into each balloon-like elastic body may be changed so that the processing pressure is different for each section of the work. The pressing plate can be divided into, for example, a pressing plate that presses a circular section located at the center of the work and a pressing plate that presses one or a plurality of annular sections concentric with the circle.

The pressing plate is a light-weight material having high rigidity so that the work (or a section of the work) can be pressed uniformly, and a material that does not become a chemical contamination source or an organic contamination source for the work (eg, a semiconductor wafer). It is preferable that it is formed by. Specifically, the pressing plate is preferably made of ceramic such as alumina or stainless steel.

The pressing plate or each pressing plate may be formed of two or more parts depending on the structure of the work holding mechanism. As described above, when the diaphragm is sandwiched between the pressing plate and attached to the pressing plate, the pressing plate preferably includes an upper portion and a lower portion, and is capable of sandwiching the diaphragm between the two portions. . The shape and dimensions of the pressing plate are not particularly limited as long as the work can be pressed against the polishing pad, and need not necessarily be a flat plate. Therefore, the part in contact with the work is flat,
The pressing plate also includes one having a partially different thickness.

It is preferable that the holding sheet is attached to at least a part, preferably all of the surface of the pressing plate so that the holding sheet contacts at least a part of the back surface of the work when the work holding mechanism holds the work. The holding sheet absorbs irregularities on the work-side surface of the pressing plate and prevents the irregularities from being transferred to the surface of the work. The holding sheet also serves to alleviate a sudden change in the processing pressure acting on the work near the outer edge of the press plate when the work is pressed by the press plate. When the holding sheet is attached to only a part of the surface of the pressing plate and contacts only a part of the back surface of the work, only the surface of the part of the work in contact with the holding sheet is pressed by the pressing plate. In other words, when the holding sheet is attached to only a part of the surface of the pressing plate, it can be said that the pressing plate comes into contact with the work only at the portion in contact with the holding sheet and presses the work.

The holding sheet is preferably a flexible elastic sheet. Specifically, the holding sheet is preferably a sheet made of polyurethane and having a thickness of 0.5 to 1.0 mm. Such a sheet is, for example, a backup sheet such as Suva 400 (trade name) manufactured by Rodel Nitta.

The present invention also relates to a work holding mechanism for pressing a work against a polishing pad and holding the work in a plane perpendicular to the pressing direction, the work holding mechanism comprising one or a plurality of pressing plates in contact with a back surface of a central portion of the work. A diaphragm that holds each pressing plate movably in the pressing direction, a balloon-like elastic body that can be in contact with the back surface of each pressing plate, and a pressing base that is in contact with the back surface of the peripheral portion of the work that is not in contact with the pressing plate are provided. When the balloon-like elastic body expands due to the pressure of the fluid supplied into the balloon-like elastic body, the surface of the central portion of the work is pressed against the polishing pad via the pressing plate, and the peripheral edge of the work is pressed via the pressing base. A work holding mechanism characterized in that a surface is pressed against a polishing pad.

The "center portion of the work" means a circular portion having a diameter corresponding to 1/2 to 3/4 of the diameter of the work, including the center of the work when the work is in the form of a disk. This circular part is preferably concentric with the workpiece.
The “periphery of the work” refers to a portion including the outer edge of the work. When the work has a disk shape, the peripheral portion of the work is an annular portion including the outer edge of the work, and has a width corresponding to １ ／ to ８ of the diameter of the work (the outer periphery and the inner periphery of the annular portion). (A distance between the annular portion). This annulus is preferably concentric with the workpiece. The “outer edge of the work” is the outermost part that defines the contour of the work. However, as described below, as in the case of “arranging a lip seal on the back surface of the outer edge of the work”, an extremely narrow width ( For example, it may refer to an annular portion having a width of about 1/40 of the diameter of the work). Therefore, for example, if the workpiece has a diameter of 200
mm, the center of the workpiece is 100 mm in diameter.
It is a circular part having a width of 50 to 25 mm including the outer edge of the work. Further, the outer edge of the work may refer to an annular portion having a width of about 5 mm or less.

When the work holding mechanism having the pressing plate and the pressing base holds the work, it cannot contact with either the pressing plate or the pressing base due to the structure of the work holding mechanism. A part that cannot be pressed may exist on the back surface of the work. The part does not correspond to either the central part or the peripheral part, and as will be described later, generally, the space comes into contact with the part when the work is held by the work holding mechanism. That is, there is no member that directly contacts that portion.

The "pressing base" acts similarly to the "pressing plate" in pressing the work, and is one form of the pressing plate. In the present specification, for convenience, a member that presses the central portion of the work is referred to as a “pressing plate”, and a member that presses the peripheral portion of the work is referred to as a “pressing base”. Therefore, the work holding mechanism having the pressing plate and the pressing base corresponds to a form in which a plurality of pressing plates are provided in the work holding mechanism described above.

The pressing plate in the work holding mechanism having the pressing plate and the pressing base has a shape corresponding to the center of the work, and has a disk shape when the work is in a disk shape. Preferred materials for forming the pressing plate are as described above. The pressing base has a shape corresponding to the peripheral portion of the work, and has an annular shape when the work is in a disk shape. The preferred material of the pressing base is the same as that of the pressing plate.

The work holding mechanism having the pressing plate and the pressing base is characterized in that the central part and the peripheral part of the work can be pressed by different members. According to this work holding mechanism, since the processing pressure can be made different between the central part and the peripheral part of the work, it is possible to effectively prevent edge dripping occurring at the peripheral part of the work without adjusting the height of the retainer ring and the like. Therefore, this work holding mechanism is preferably used, for example, when the processing pressure at the peripheral edge of the work and the processing pressure at the center of the work are necessarily different even when the entire work is pressed by the same pressure with one pressing plate. . Specifically, this work holding mechanism is suitable for polishing a semiconductor wafer substrate using a viscoelastic polishing pad.

Preferably, the pressing base also presses the peripheral portion of the work against the polishing pad in the same manner as the pressing plate.
Specifically, a diaphragm that holds the pressing base movably in the pressing direction and a balloon-like elastic body that can contact the back surface of the pressing base are provided, and the balloon-like elastic body expands due to the pressure of the fluid supplied to the balloon-like elastic body. By doing so, it is preferable that the surface of the peripheral portion of the work is pressed against the polishing pad via the pressing base. When this pressing method is employed, the processing pressure becomes more uniform, and aggregation of the abrasive grains due to leakage of the fluid is prevented, as in the case of using the pressing plate.

Alternatively, instead of pressing the peripheral portion of the work using the pressure of the fluid, the peripheral portion of the work is pressed against the polishing pad by, for example, pressing down a pressing base with a cylinder or the like.

In the work holding mechanism having the pressing plate and the pressing base, the balloon-like elastic body that can contact the back surface of the pressing base is the same as the above-described balloon-like elastic body that can contact the back surface of the pressing plate. Therefore, the detailed description is omitted here. However, in the balloon-like elastic body which can be in contact with the back surface of the pressing base, the shape of the portion in contact with the back surface of the pressing base differs depending on the shape of the pressing base with which it is in contact. For example, when the pressing base is annular, the shape of the portion of the balloon-like elastic body that contacts the back surface of the pressing base also becomes annular.

In a work holding mechanism having a pressing plate and a pressing base, the diaphragm for holding the pressing plate movably in the pressing direction has a part attached to the pressing plate and another part attached to a member other than the pressing plate. , So that a flexure is formed between the two parts. The specific mounting method is as described above. Members other than the pressing plate to which the diaphragm is attached include a pressing base in addition to the holding base and the holding member exemplified above.

A part of the diaphragm that holds the pressing base movably in the pressing direction is also attached to the pressing base, and the other part is attached to a member other than the pressing base. Other members other than the pressing base include a holding base and a holding member. The shape of the diaphragm is an annular thin plate (for example, a sheet) when the work is a disk, and when the inner peripheral portion is attached to the pressing base, the outer peripheral portion is attached to a member other than the pressing base.
When the outer peripheral portion is attached to the pressing base, the inner peripheral portion is attached to a member other than the pressing base. In either case,
The portion between the outer peripheral portion and the inner peripheral portion is elastically deformed (eg, bent) as a bent portion.

In the present specification, the terms "outer peripheral portion" and "inner peripheral portion" refer to a portion having an opening at the center (for example, a ring-shaped portion) including an outer edge and a portion including an inner edge. As described later, when the hole is formed along the arc of the circle, the inner edge and the outer edge of the hole are referred to as the inner circumference and the outer circumference of the hole, respectively.

Also in the work holding mechanism having the pressing plate and the pressing base, when the work holding mechanism holds the work, the holding sheet is provided on at least a part of the back surface of the center portion of the work and at least a part of the back surface of the peripheral portion of the work. It is preferable to attach the holding sheet to at least a part of the surface of the pressing plate and at least a part of the surface of the pressing base so that the holding sheet is in contact with the holding sheet. The holding sheet is preferably attached to all of the pressing plate surface and all of the pressing base surface. Since the holding sheet attached to at least a part of the surface of the pressing plate contacts at least a part of the back surface at the center of the work,
It is referred to as a center holding sheet for convenience. In addition, the holding sheet attached to at least a part of the surface of the pressing base is in contact with the back surface of the peripheral portion of the work, and is therefore referred to as a peripheral holding sheet for convenience. Each sheet has the same role and preferable materials as those constituting the same as the holding sheet described above.

When the center holding sheet is attached only to a part of the surface of the pressing plate and contacts only a part of the back surface of the work,
The pressing plate presses only the surface of the portion in contact with the holding sheet in the central portion of the work. Similarly,
When the peripheral holding sheet is attached only to a part of the pressing base surface and contacts only a part of the back surface of the work, the pressing base presses the part of the peripheral part of the work that is in contact with the peripheral holding sheet. Surface only. As the peripheral holding sheet, a lip seal (for example, an O-ring) arranged on the back surface of the outer edge of the work may be used.
Only the outer edge in contact with the lip seal is pressed by the pressing base.

The portion of the work that is not pressed by the absence of the center holding sheet can be pressed by the pressing plate if the center holding sheet is attached to the entire surface of the pressing plate, and therefore belongs to the center. Similarly, the portion of the work that is not pressed due to the absence of the peripheral holding sheet can be pressed by the pressing base if the peripheral holding sheet is attached to the entire surface of the pressing base, and thus belongs to the peripheral portion. However, in the central part and / or peripheral part of the work, there is a portion that is not pressed against the polishing pad by the pressing plate and / or the pressing base because it does not contact the holding sheet, and when the work is held by the work holding mechanism. If a space is formed in contact with the part (that is, the part does not come into contact with any member of the work holding mechanism), even if the part belongs to the central part and / or the peripheral part, it will be described below. In some cases, the “intermediate portion” may be referred to for convenience.

As described above, the work holding mechanism of the present invention may have a space formed in contact with a part of the back surface of the work when the work is held. This space is formed so that the work does not come into contact with any member of the work holding mechanism. As described above, such a space may be such that neither the press plate nor the press base can contact the work on the back surface of the work, or only a part of the surface of the press plate and / or the press base is retained. In some cases, it is inevitably formed due to the structure of the work holding mechanism, such as when a sheet is attached. For example, even when the work holding sheet is provided at the center of the work and a lip seal is arranged at the outer edge of the work as a holding sheet, a space corresponding to the thickness of the work holding sheet is provided between the center of the work and the outer edge. The part is formed in contact with the back surface of the work. Generally, a space that contacts a part of the back surface of a work is formed between a peripheral portion (or an outer edge) and a center portion of the work.
In the present specification, such a space portion may be referred to as an “intermediate space portion” for convenience, and a portion of the work that is in contact with the intermediate space portion may be referred to as an “intermediate portion” as described above.

The intermediate space is generally an annular portion when the work is in the form of a disk, and its width is preferably 1/20 to 1/7 of the diameter of the work. Therefore, when the workpiece is a disk having a diameter of 200 mm, the intermediate space portion is
Preferably, it is an annular portion having a width of 10 to 30 mm. If the intermediate space portion is in contact with a wide area on the back surface of the work, the area of the work pressed by the pressing plate and the pressing base becomes small, and the intended effect of the present invention cannot be obtained.

The intermediate space may be supplied with a fluid.
In order to supply a fluid to the intermediate space, it is necessary to connect the space with an appropriate fluid pipe and to prevent fluid leakage. When the lip seal is located on the back surface of the outer edge of the work, the lip seal forms an air-tight or liquid-tight seal to prevent fluid leakage. By supplying a fluid having an appropriate pressure to the intermediate space, the surface of the intermediate portion of the work can be pressed against the polishing pad with an appropriate pressure.
In this case, it is necessary to supply the fluid by appropriately selecting a pressure or the like so that the abrasive particles do not aggregate due to the leakage.

It is preferable that a fluid is independently supplied to the intermediate space. For this purpose, an independent fluid conduit for supplying fluid only to the intermediate space is provided so that a fluid having a pressure different from the pressure of fluid supplied to other portions (for example, a balloon-like elastic body) can be supplied. Is preferred. When the fluid is independently supplied to the intermediate space, the processing pressure may be different between the central portion (excluding the intermediate portion) and the intermediate portion of the work. In the case where the pressing base is provided, the processing pressure may be different between the central portion (excluding the intermediate portion), the peripheral portion (excluding the intermediate portion), and the intermediate portion of the work. As a result, the distribution of the processing pressure can be controlled more accurately, and the flatness of the work surface can be further improved.

The intermediate space can be evacuated or reduced in pressure by evacuating it through a fluid line. If the intermediate space is evacuated, the work is attracted to the work holding head, so that the work is substantially fixed to the work holding head. When the vacuum is released, the work can be easily removed from the holding head. The evacuation is preferably performed when the work is transported before and after polishing the work. The evacuation may be performed during the polishing of the work as long as the uniformity of the polishing of the work is not affected. In that case, polishing proceeds while the work is stably fixed by the work holding head.

The work holding mechanism has the above intermediate space,
In the case of having only the pressing plate without the pressing base, in one preferred embodiment, the pressing plate is in a lip seal shape at the outer edge of the work and is in contact with the back surface of the work to seal the intermediate space, that is, the pressing plate Has a structure that functions as a lip seal at the outer edge of the work. Specifically, it is preferable that the pressing plate has an annular convex portion that can be in contact with the back surface of the work at the outer edge of the work.

The work holding mechanism has the intermediate space,
In a preferred embodiment, even when the pressing base is provided, the pressing base is in contact with the back surface of the work in a lip seal shape at the outer edge of the work. The preferred specific embodiments are as described above for the pressing plate.

In any of the above-described work holding mechanisms, it is preferable to form a fluid conduit on the pressing plate as necessary. Specifically, the fluid conduit is provided so as to extend from the back surface of the pressing plate and pass through the pressing plate. For example, a fluid conduit extending straight from the back surface of the pressing plate to the side surface of the pressing plate and having ports (ports) on the back surface and the side surface of the pressing plate may be provided. The fluid conduit may extend from the back surface of the pressing plate to the surface of the pressing plate, that is, may extend through the entire thickness of the pressing plate. Alternatively, the fluid conduit may have an L-shape that extends from the back surface over a part of the thickness, bends halfway, extends in the radial direction, and reaches the side surface.

The fluid conduit provided on the pressing plate mainly functions as a vacuum conduit for evacuating. Therefore, the configuration and position of the fluid conduit are determined so that the work is adsorbed to the work holding head when the fluid is evacuated through the conduit. As long as the fluid conduit penetrates the entire thickness of the pressing plate and is evacuated from a port (port) on the back surface of the pressing plate, the work can be easily attracted to the work holding head.

When the fluid conduit passes through the entire thickness of the pressing plate and the holding sheet is located between the pressing plate and the work,
It is necessary that a through-hole is provided in the holding sheet, and the through-hole is connected to the fluid conduit and becomes a part of the fluid conduit. If there is no through hole in the holding sheet, the work cannot be attracted to the holding sheet.

The port on the back side of the pressure plate of the fluid conduit is closed by the balloon-like elastic body when the fluid is supplied into the balloon-like elastic body and the balloon-like elastic body expands. Is preferred. In some cases, the suction of the work can be easily released by closing one port of the fluid conduit with the balloon-like elastic body.

The work holding mechanism of the present invention is a diaphragm having a thickness partially different from the back surface of the work instead of one or more pressing plates and a diaphragm for holding the pressing plate movably in the pressing direction. May be provided with a diaphragm that is in contact with at least a part of. In this work holding mechanism, a portion having a large thickness of the diaphragm acts as a pressing plate to be displaced in a pressing direction and presses a work against a polishing pad, and a portion having a large thickness is elastically deformed so that a portion having a large thickness is deformed. The displacement in the pressing direction is controlled. Therefore, the portion of the diaphragm that contacts the back surface of the workpiece is at least a part, and preferably all, of the thick part corresponding to the pressing plate.

When diaphragms having different thicknesses are used, the structure of the pressing mechanism is simplified, and the number of stagnation points of dust and the like that cause scratches in the work holding mechanism is reduced. In addition, since the portion corresponding to the pressing plate can be formed only by increasing the thickness, the work can be more easily pressed by the plurality of sections as compared with the case where a plurality of pressing plates are used.

The diaphragms having different thicknesses may be used in combination with a pressing plate. For example, a diaphragm having a different thickness and a pressing plate laminated and integrated with a thicker portion may be used. In such a case, it can be said that the diaphragms having different thicknesses are provided in place of the “part” of the pressing plate and the diaphragm that holds the pressing plate movably in the pressing direction. The pressing plate is inserted between the balloon-like elastic body and the diaphragm as a kind of adjusting member when, for example, the work cannot be pressed against the polishing pad with the diaphragm even if the balloon-like elastic body expands due to design reasons. You. When the pressing plate is used as such, the work is pressed against the polishing pad via the pressing plate and the diaphragm. By using the pressing plate as the adjusting member, it is not necessary to form the diaphragm into a complicated shape in consideration of the position of the balloon-like elastic body, and the work can be accurately pressed against the polishing pad.

The work holding mechanism of the present invention also includes a diaphragm having a thickness partially different from that of a part or all of one or more pressing bases and a diaphragm for holding the pressing base movably in the pressing direction. The diaphragm may be provided in contact with at least a part of the back surface of the work. In place of the “part of the pressing base” and the diaphragm that holds the pressing base movably in the pressing direction, as a mode in which a diaphragm having a partially different thickness is provided, pressing is performed on a diaphragm having a partially different thickness. There is a mode in which the bases are stacked and integrated. When a diaphragm having a thickness that is partially different is used instead of the pressing base and the diaphragm holding the pressing base, the diaphragm is integrated with the pressing plate and the diaphragm used in place of the diaphragm holding the pressing plate. May be. For example, from the periphery of the work to the center of the work,
An integral diaphragm with small and thick portions alternating may be used.

It is preferable that the work holding mechanism of the present invention is further provided with a holding member surrounding the outer edge (or side surface) of the work. The holding member is provided to prevent the work from coming off the work holding head during polishing. The holding member is specifically a retaining ring.

When the holding member is provided in the work holding mechanism of the present invention, the holding member is preferably held by a diaphragm which holds the holding member movably in the pressing direction, and is preferably pressed against the polishing pad by an appropriate pressing means. . Specifically, the holding member (for example, a retainer ring) is held by a diaphragm having an axially symmetric structure whose axis is a symmetric axis passing through the center of the holding mechanism. Specifically, such a diaphragm is a ring-shaped plate whose center is on the axis of symmetry and whose radial direction is perpendicular to the axis of symmetry, and the portion between the outer peripheral portion and the inner peripheral portion is It is elastically deformed (for example, bent) as a bending portion.

If the holding member is held by the annular diaphragm, even if the holding member moves in the pressing direction and stress is generated in the diaphragm, the diaphragm has a symmetrical structure, so that the diaphragm exerts a force acting in the radial direction. It is elastically deformed so as to be balanced around the axis of symmetry. That is, even if the holding member moves in the pressing direction, the center of the diaphragm does not shift significantly, and the center of the holding member held by the diaphragm does not shift significantly. Therefore, if the holding member is held by the diaphragm which can be elastically deformed in this manner, the displacement of the holding member in the horizontal direction can be effectively prevented. On the other hand, the diaphragm is easily elastically deformed (for example, bent) in the pressing direction, so that the holding member can be moved in the pressing direction even with a small force.

Preferably, the holding member is also pressed against the polishing pad in the same manner as the pressing plate. Specifically, a diaphragm that holds the holding member movably in the pressing direction and a balloon-like elastic body that can be in contact with the back surface of the holding member are provided, and the balloon-like elastic body expands due to the pressure of the fluid supplied into the balloon-like elastic body. By doing so, it is preferable that the holding member is pressed against the polishing pad.

By pressing the holding member against the polishing pad, the work is less likely to come off from the holding head during polishing, so that the work jumps out and the work is thereby prevented from being damaged. Further, the polishing pad is pressed in the vicinity of the outer edge of the work to change the compression deformation state of the polishing pad, thereby preventing the edge of the work from sagging. That is, by pressing the holding member, it is possible to control the balance of the processing pressure of the central portion, the peripheral portion, the intermediate portion, and the outer edge of the workpiece with high accuracy.

The balloon-like elastic body that can contact the back surface of the holding member is the same as the balloon-like elastic body that can contact the back surface of the pressing plate described above. Therefore, the detailed description is omitted here. However, in the balloon-like elastic body which can be in contact with the back surface of the holding member, the shape of the portion in contact with the back surface of the holding member differs depending on the shape of the holding member with which it is in contact. For example, when the holding member is annular, the shape of the portion of the balloon-like elastic body that contacts the back surface of the holding member also becomes annular.

The diaphragm for holding the holding member is preferably annular, and the outer periphery is supported by the holding base and the inner periphery is supported by the holding member. The holding base that supports the outer peripheral portion of the diaphragm is the main body of the work holding mechanism that is located on the outer peripheral side of the holding member. Here, "support" means that the outer peripheral portion or the inner peripheral portion of the diaphragm is substantially fixed to the holding base or the holding member, respectively. When the diaphragm is supported in this way, the diaphragm can hold the holding member uniformly throughout. In addition, even if the diaphragm is thin, the force acting on the diaphragm does not twist the diaphragm and does not become a compressive force to shrink the diaphragm, but becomes a tensile force at all times. It does not easily bend. This is because the bending portion of the diaphragm located between the holding base and the holding member is constantly pulled and elastically deformed while the holding member is moving in the pressing direction. A restoring force acts on the elastically deformed diaphragm, which becomes a force for pulling the retainer ring. Due to the balance of these forces, a force that causes buckling does not easily act on the diaphragm.

In the case where the diaphragm is annular, a plurality of holes along the circumference are formed on the inner peripheral portion and the outer peripheral portion of the diaphragm at intervals, and the holding member and the holding base are formed by two holes each having a concave portion and a convex portion. Configured to include members,
By fitting the convex portion of the holding member into the concave portion through the hole formed in the inner peripheral portion of the diaphragm, and fitting the convex portion of the holding base into the concave portion through the hole formed in the outer peripheral portion of the diaphragm, It is preferable to pinch the hole. As described above, each of the holding member and the holding base is composed of two members having a concave portion and a convex portion, and when the convex portion is fitted into the concave portion and the diaphragm is sandwiched, the diaphragm is compared with, for example, bolting. Is longer. Since the horizontal force applied to the diaphragm is dispersed at the portion sandwiched between the holding member and the holding base, by making the portion to be sandwiched of the diaphragm longer, the stress concentration is more dispersed, and therefore, the buckling of the diaphragm is caused. Can be further reduced.

It is preferable that a hole formed in the diaphragm is provided with a claw-shaped protruding portion that protrudes in the radial direction of the diaphragm, and the protruding portions of the holding member and the holding base are elastically supported in the radial direction by the protruding portions. As described above, when the protrusion having the claw shape that protrudes is provided in the hole and the protrusion of the holding member or the holding base is inserted into the hole, the protrusion is deformed by the protrusion, and the protrusion elastically deforms the protrusion in the horizontal direction. To support. According to such a configuration, even when a horizontal force acts on the diaphragm during processing, the protruding portion is elastically deformed, so that the bending portion of the diaphragm is buckled and deformed due to the force acting in the horizontal direction. Can be prevented. The protrusion may be provided on only one of the inner circumference and the outer circumference of the hole, or may be provided on both.

When the projection is supported by the projection, the projection of the holding member is supported by a projection formed on one of the inner and outer circumferences of the hole, and the projection of the holding base is supported by the holding member. It is preferable that the projection is supported by a projection formed on the circumference opposite to the circumference on which the projection supporting the projection is formed. For example, when the protrusion of the holding member is supported by a protrusion formed on the inner periphery of the hole, the protrusion of the holding base is preferably supported by a protrusion formed on the outer periphery of the hole. With this support, only one side of any of the protrusions comes into contact with the diaphragm. Therefore, the holding member can be easily removed only by elastically deforming the protrusion,
There is no plastic deformation of the diaphragm.

In the work holding mechanism of the present invention, a groove is formed on the surface of the peripheral edge of the pressing plate, and a substantially sealed fluid conduit is formed between the groove and the work when the work is held. May have been. The groove is specifically formed circumferentially. The fluid conduit is supplied with fluid from a suitable fluid supply, and the pressure of the fluid filling the fluid conduit partially presses the workpiece against the polishing pad. By forming such a groove so that a fluid conduit is formed between the groove and the work when the work is held, the lip seal or the periphery holding sheet may be able to be eliminated. Eliminating them means that they do not need to be replaced when they have deteriorated, so that the labor required for maintenance of the work holding mechanism can be reduced.

When the work is a disk, the groove preferably has a width corresponding to about 1/50 to about 1/30 of the diameter of the work. A plurality of grooves may be formed, for example, so as to be concentric. The position and number of the grooves are determined as appropriate according to the type of the work and the processing pressure profile. Therefore, for example, when the work is in the form of a disc having a diameter of 200 mm, the width of the groove is preferably about 4 to 7 mm. When the work holding mechanism holds the work, the outer circumference of the groove is, for example, different from the work. Concentric diameter 1
The pressing plate can be formed so as to overlap with a 95 mm circle.

When the work holding mechanism of the present invention has a pressing base, a groove may be formed in the pressing base, and a substantially closed fluid conduit may be formed between the groove and the work. The advantage of forming the groove in the pressing base is the same as the advantage of forming the groove in the pressing plate. The preferred dimensions and the like of the grooves formed on the pressing base are the same as those of the grooves formed on the pressing plate. The groove may be formed on both the pressing plate and the pressing base.

The present invention further provides a polishing apparatus having the work holding mechanism of the present invention. The polishing apparatus of the present invention enables a workpiece to be polished with a uniform processing pressure over a wider portion of the workpiece. In addition, during polishing by the polishing apparatus of the present invention, the fluid pressing the work does not substantially leak, and the agglomeration of the abrasive grains due to the drying of the polishing liquid does not occur. Therefore, the work machined by the polishing apparatus of the present invention has a small "out-of-edge" portion and a small number of scratches on the polished surface, so that the yield is improved.

The work holding mechanism of the present invention can be applied to a conventional polishing apparatus. In the polishing apparatus, the work holding mechanism of the present invention is used by being applied to a work holding head. Generally, a polishing apparatus includes means for moving a work relative to a polishing pad, and polishing of the work is performed by moving the work relatively to the polishing pad. Specifically, for example, a polishing pad may be attached to a movable platen, and the platen may be eccentrically moved in a small circle (orbital movement) to perform polishing. Alternatively, the work holding head may be connected to a driving device, and the work holding head may be rotated and / or rocked. The platen and the work holding head may be moved simultaneously. The polishing pad is generally placed and supported on a hard surface plate. If necessary, a soft sheet is arranged between the polishing pad and the surface plate. The soft sheet is provided to make the polishing pad follow the undulation of the work. Further, the polishing apparatus may be provided with a conventionally used apparatus, for example, a work loading / unloading apparatus.

The present invention also relates to a method of polishing a work by pressing a surface to be polished of the work against a polishing pad and moving the work relatively to the polishing pad, wherein the pressing plate is indirectly pressed by a fluid pressure. And a pressing plate that presses at least a part of the back surface of the work with a pressing plate, thereby pressing at least a part of the polished surface of the work against the polishing pad. In this polishing method, the pressing plate is indirectly displaced by the pressure of the fluid, that is, at least a part of the back surface of the work is pressed by the pressing plate by displacing the pressing plate without directly contacting the fluid, and A part of the surface to be polished of the work is pressed against the polishing pad. Displacing the pressing plate in such a manner involves holding the pressing plate movably in the pressing direction with a diaphragm and supplying fluid to the balloon-like elastic body provided on the back surface of the pressing plate to expand the balloon-like elastic body. Can be implemented. This polishing method is preferably performed by the polishing apparatus of the present invention including the work holding mechanism of the present invention.

[0076] Preferably, the polishing method of the present invention includes indirectly pressing the back surface of the holding member surrounding the outer edge of the workpiece with the pressure of the fluid, thereby pressing the holding member against the polishing pad. The polishing method is further characterized in that the back surface of the holding member is pressed indirectly by the pressure of the fluid, that is, without directly contacting the fluid, thereby pressing the surface of the holding member against the polishing pad. . Pressing the holding member against the polishing pad in such a manner holds the holding member movably in the pressing direction with a diaphragm, and supplies a fluid into the balloon-like elastic body provided on the back surface of the holding member to cause the balloon-like elastic body to be pressed. This can be done by inflation. This polishing method is preferably performed by the polishing apparatus of the present invention having the work holding mechanism of the present invention.

The present invention relates to a chemical mechanical polishing (Chemical Mecha).
nical polishing; sometimes abbreviated as CMP). The CMP method is polishing performed by utilizing the fact that a polishing liquid chemically reacts with a work on a surface to be processed. The present invention also provides a polishing method other than the CMP method, for example, a mechanical polishing (MP) method or a mechanochemical polishing (MCP).
g) The method is also applicable.

[0078]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific embodiment of the work holding mechanism of the present invention will be described with reference to the drawings. Figure 2
FIG. 5 shows a work holding mechanism according to an embodiment of the present invention. In each of the drawings, each work is a semiconductor wafer. In each figure, the work is held by the work holding mechanism,
This shows a state where the polishing pad and the work are in contact with each other. Although not shown, in any of the embodiments, polishing is performed while supplying a polishing liquid containing polishing abrasive grains.

FIG. 2 shows a first embodiment. The work holding mechanism (10) has a holding base (1) with a rotating shaft (12).
1) Disc-shaped, having a pressing plate (13), a pressing base (17), a retainer ring (21) as a holding member, a center holding sheet (14) in contact with the center of the work, and a lip seal (18) (3) is held. A polishing pad (28) for polishing the work (3) is attached to a surface plate (29).

The work (3) is a disk having a diameter of 200 mm. The pressing plate (13) has a diameter of 100 concentric with the work (3).
It is provided so as to be able to press the central part of the work, which is a circular part of mm. The pressing base (17) is provided so that its inner periphery is located above the peripheral edge of an annular work overlapping with a circle having a diameter of 150 mm concentric with the work (3). The lip seal (18) has a width of 5 mm. In FIG. 2, an intermediate space (30) is formed between the center holding sheet (14) and the lip reel (18).

The center holding sheet (14) has a function of dispersing and averaging the vertical pressure applied locally from the back of the work. The center holding sheet (14) is, for example, Suva 400 (trade name) manufactured by Rodel Nitta. The center holding sheet (14) is attached to the surface of the pressing plate (13) by a double-sided adhesive tape. The lip seal (18) is arranged so as to be located at the outer edge of the work, and serves to seal the intermediate space (30) to the outside. The lip seal (18) can be, for example, an O-ring made of a resilient material, or a narrow annular sheet made of the same material as the central holding sheet.

The pressing plate (13) is held by a diaphragm (16) so as to be movable in the pressing direction and in the opposite direction (vertical direction in the figure). On the back side of the pressing plate (13),
A balloon-like elastic body is provided. In the illustrated embodiment, the elastic sheet (15) and the holding base (11) form a space (100) to form a balloon-like elastic body. When compressed air is supplied as fluid to the space (100) through the fluid pipe (26), the elastic sheet (15) constituting the balloon-like elastic body expands downward.

When the elastic sheet (15) constituting the balloon-like elastic body is expanded by the compressed air, the pressing plate (13) and the center holding sheet (14) are displaced, and the center of the work (3) is polished with the polishing pad (15). 28) is pressed. That is, the pressure of the compressed air in the space (100) of the balloon-like elastic body is transmitted to the center of the work (3) via the pressing plate (13) and the center holding sheet (14), whereby the work (3) Is pressed against the polishing pad (28).

In the illustrated embodiment, the elastic sheet (15) constituting the balloon-like elastic body is a disk-shaped sheet (for example, a neoprene rubber sheet having a thickness of 0.1 mm). The elastic sheet (15) is attached by crimping to the holding base (11) with an annular pressing plate (24a) so that fluid (air) does not leak. Space part of balloon-like elastic body (100)
The balloon-like elastic body may not be in contact with the pressing plate when it is not inflated, as long as the pressure of the compressed air supplied to the pressure plate is transmitted to the pressing plate.

The free portion of the diaphragm (16) bends simultaneously with the displacement of the pressing plate (13). In FIG. 2, the diaphragm (16) is a disc-shaped elastic sheet (for example, a neoprene rubber sheet having a thickness of 0.1 mm). The periphery of the diaphragm (16) is fixed to the pressing base (17) by bolts via the plate-like member (25b), and the center of the diaphragm (16) is fixed to the pressing plate (13) by bolts. ). Specifically, the center of the diaphragm (16) is formed by pressing the pressing plate (13) with the upper portion (13a) and the lower portion (13).
b) and the diaphragm (1
6) is sandwiched and fixed by bolting from the upper part (13a). Therefore, the bending portion of the diaphragm (16) is a portion located between the pressing plate (13) and the pressing base (17). The dimensions of the bending portion are determined according to the movable distance of the pressing plate (13) and the material of the diaphragm (16). The movable distance of the pressing plate (13) is a design item of the work holding mechanism, and is determined by how much the pressing plate (13) needs to be moved.

The pressing base (17) is a diaphragm (20)
Movably in the pressing direction and the opposite direction. The diaphragm (20) is an annular elastic sheet (for example, a neoprene rubber sheet having a thickness of 0.1 mm). On the back side of the pressing base (17), a balloon-like elastic body is provided. In the illustrated embodiment, the elastic sheet (19) and the holding base (11) form a space (102) to constitute a balloon-like elastic body. When compressed air is supplied as a fluid to the space (102) through the fluid pipe (27), the balloon-like elastic sheet (1
9) expands downward.

When the elastic sheet (19) constituting the balloon-like elastic body is expanded by the compressed air, the pressing base (1)
7) and the lip seal (18) are displaced, and the periphery of the work (3) is pressed against the polishing pad (28). That is, the pressure of the compressed air in the space (102) of the balloon-like elastic body is transmitted to the work (3) via the pressing base (17) and the lip seal (18), whereby the peripheral portion of the work (3) is moved. Pressed by the polishing pad (28).

The lip seal (18) is provided in the intermediate space (30).
The contact area between the lip seal (18) and the work is small because the purpose is to exclusively prevent the leakage of the fluid when the fluid is supplied to the work. Is extremely small. When it is desired to increase the area of the portion pressed by the pressing base, it is preferable to use a wide annular holding sheet in contact with the periphery of the work over a wider area as the periphery holding sheet.

In the illustrated embodiment, the elastic sheet (19) constituting the balloon-like elastic body is an annular sheet (for example, a neoprene rubber sheet having a thickness of 0.1 mm). The elastic sheet (19) has its inner peripheral part and outer peripheral part attached to the holding base (11) by annular pressing plates (24b, 24c) by press-fitting to the holding base (11) so that fluid (air) does not leak. . As long as the pressure of the compressed air supplied to the space (102) of the balloon-like elastic body is transmitted to the pressing base, the balloon-like elastic body may not be in contact with the pressing base when not inflated.

The free portion of the diaphragm (20) bends simultaneously with the displacement of the pressing base (17). In the illustrated embodiment, the inner periphery of the diaphragm (20) is sandwiched between the plate-like member (25c) and the holding base (11) and fixed with bolts, and the outer periphery of the diaphragm (20) is connected to the pressing base (17). It is fixed and holds the pressing base (17). Specifically, the outer periphery of the diaphragm (20) divides the pressing base (17) into two parts, an upper part (17a) and a lower part (17b), and sandwiches the diaphragm (20) between the two parts. , Upper part (17
It is fixed by bolting from the side of a).
Therefore, the bending portion of the diaphragm (20) is a portion located between the holding base (11) and the pressing base (17). The size of the flexible portion of the diaphragm (20) is determined according to the movable distance of the pressing base (17), the material of the diaphragm (20), and the like, like the flexible portion of the diaphragm (16).

The pressing plate (13) and the pressing base (17) are provided so as to be movable in the pressing direction. The horizontal movement of the pressing base (17)
The diaphragm (20) having an inner peripheral portion fixed to the inner surface of the pressing plate (13) prevents the pressing plate (13) from moving in the horizontal direction.
The diaphragm (16) whose outer peripheral portion is fixed to (7) is suppressed.

In the illustrated embodiment, the intermediate space (30)
Is defined by a pressing plate (13), a center holding sheet (14), a pressing base (17), a diaphragm (16), a lip seal (18), a plate member (25b), and a work (3).
The intermediate space has different shapes and dimensions depending on the structure of the work holding mechanism, and the members defining the same may be different. Fluid is supplied to the intermediate space (30) through a fluid pipe (37) provided in the holding base (11) and a fluid pipe (17c) provided in the pressing base. It has become.
When the fluid is supplied to the intermediate space (30), the fluid causes the annular intermediate portion of the work (in FIG. 2, the portion where the center holding sheet (14) and the lip seal (18) are not in contact).
Is pressed against the polishing pad (28).

The retainer ring (21) is held by a diaphragm (22) so as to be movable in the pressing direction and the opposite direction. The diaphragm (22) is an annular metal plate (for example, a stainless steel plate or a Hastelloy plate having a thickness of 0.1 mm). A balloon-like elastic body is provided on the back side of the retainer ring (21). In the illustrated embodiment, the holding base (11) and the elastic sheet (23) form a space (104) to form a balloon-like elastic body. When compressed air is supplied to the space (104) as a fluid via the fluid conduit (36), the elastic sheet (23) constituting the balloon-like elastic body expands downward.

When the elastic sheet (23) constituting the balloon-like elastic body is expanded by the compressed air, the retainer ring (21) is displaced and pressed against the polishing pad (28). That is, the pressure of the compressed air in the space (104) of the balloon-like elastic body is transmitted to the retainer ring (21), and the retainer ring (21) is pressed against the polishing pad (28).

In the illustrated embodiment, the elastic sheet (23) constituting the balloon-like elastic body is an annular sheet (for example, a neoprene rubber sheet having a thickness of 0.1 mm). The elastic sheet (23) has its inner peripheral portion and outer peripheral portion attached to the holding base (11) by annular press plates (24d, 24e) by crimping so as to prevent fluid (air) from leaking. . As long as the pressure of the compressed air supplied to the space (104) of the balloon-like elastic body is transmitted to the retainer ring, the balloon-like elastic body may not be in contact with the retainer ring when not inflated.

When the retainer ring (21) is pressed, the free portion of the diaphragm (22) bends at the same time. The outer periphery of the diaphragm (22) is fixed to the holding base (11) via the plate member (25e), and the inner periphery is fixed to the retainer ring (21) to hold the retainer ring (21). I have. Therefore, the bending portion of the diaphragm (22) is a portion located between the holding base (11) and the retaining ring (21). The dimensions of the flexure of the diaphragm (22)
Like the flexible portion of the diaphragm (16), it is determined according to the movable distance of the retainer ring (21), the material of the diaphragm (22), and the like.

The relationship between the diaphragm (22), the holding base (11) and the retainer ring will be described in detail with reference to FIGS. FIG. 6 is a perspective view of the diaphragm, and FIG. 7 is a schematic enlarged view of a retainer ring and a holding base shown on the right side of FIG. Diaphragm (22)
Is fixed between the holding base (11) and the plate member (25e). The inner peripheral portion of the diaphragm (22) is provided with a retainer ring (21) for an upper portion (21a) and a lower portion (21b).
The diaphragm is sandwiched between the two parts. The diaphragm (22) is annular, and has a plurality of holes (22a) along the circumferential direction on the outer periphery as shown in FIG.
A plurality of holes (22b) are formed in the inner peripheral part along the circumferential direction. On the outer periphery of the hole (22a) and the inner periphery of the hole (22b), claw-shaped claws (22c, 22d) protruding toward the inside (radial direction) of the hole are formed.

Furthermore, holes (22
e) is formed. This is for fixing between the holding base (11) and the plate-like member (25e) and between the upper part (21a) and the lower part (21b) of the retainer ring by bolting. Bolt is a hole (22e)
Through both ends of the. Although not shown, the holding base (11), the plate-like member (25e), and the upper part (21a) and the lower part (21b) of the retainer ring also have openings for bolting. Holding base (1
Bolts are fitted into the openings and holes (22e) between the plate-like member (1) and the plate-like member (25e) and between the upper part (21a) and the lower part (21b) of the retainer ring. ing.

As shown in FIG. 7, convex portions (25f) are formed on the upper surface of the plate-like member (25e) at intervals along the circumferential direction, and the lower surface of the holding base (11) is formed. Are formed with recesses (11a) at intervals along the circumferential direction. The intervals between the projections (25f) and the depressions (11a) correspond to the intervals between the holes (22a) formed in the diaphragm. The convex portion (25f) provided on the plate-like member (25e) is formed in a concave portion (11a) provided on the holding base (11) through a hole (22a) provided on the outer peripheral portion of the diaphragm (22). Is fitted to. At this time, as shown in the drawing, the claw-like portion (22c) formed on the outer periphery of the hole (22a) is deformed, and is press-fitted (for example, a press-fitting allowance of about 0.1 mm) on the outer peripheral side, and the gap is formed on the inner peripheral side. Fitting (for example, clearance about 0.1 mm).

On the lower surface of the upper portion (21a) of the retainer ring, there are formed protrusions (21c) at intervals along the circumferential direction, and on the upper surface of the lower portion (21b) of the retainer ring. Are formed with concave portions (21d) at intervals along the circumferential direction. The intervals between the projections (21c) and the depressions (21d) correspond to the intervals between the holes (22b) formed in the diaphragm. The projection (21c) provided on the upper part (21a) of the retainer ring is provided on the lower part (21b) of the retainer ring via a hole (22b) provided on the inner peripheral part of the diaphragm (22). Into the recess (21d). At this time, as shown in the drawing, the claw-shaped portion (22d) formed on the inner periphery of the hole (22b) is deformed, and is press-fitted (for example, a press-fitting allowance of about 0.1 mm) on the inner periphery, and is formed on the outer periphery. A gap fit (for example, a gap allowance of about 0.1 mm) is obtained.

As described above, fitting the convex portion to the concave portion,
Work holding mechanism (10) by clamping the outer and inner peripheral parts of the diaphragm by bolting
When the frictional force is applied to the retainer ring (21) when the
Buckling does not occur in the diaphragm (22), and thus the horizontal displacement of the retainer ring (21) is prevented. Further, when the retainer ring (21) moves in the pressing direction, even if a force that greatly deforms the diaphragm (22) acts, the claw-like portions (22c, 22d) of the diaphragm deform,
Since the force is released, the diaphragm (22) is not locally permanently deformed, and the displacement of the retainer ring (21) in the horizontal direction is prevented. The claw-shaped portions (22c, 22d) also absorb the processing error in the radial direction of the protrusions (25f, 21c) formed at intervals by elastic deformation.

Next, supply of fluid (compressed air) to the space (100, 102, 104) and the intermediate space (30) of the balloon-like elastic body and control of the processing pressure will be described with reference to FIG. . The work holding mechanism and the polishing pad shown in FIG. 3 are the same as those described with reference to FIG. As shown in FIG. 3, fluid conduits (26, 27, 27) for supplying compressed air to the spaces (100, 102, 104) and the intermediate space (30) of each balloon-like elastic body of the work holding mechanism. 36, 37) are connected to precision electronic regulators (31, 32, 33, 34), respectively.

The precision electronic regulators (31, 32, 33)
The pressure of the compressed air supplied to the space (100, 102, 104) of each balloon-shaped elastic body is controlled. The precision electronic regulator (34) controls the pressure of the compressed air supplied to the intermediate space (30). Each precision electronic regulator is independent, so that the processing pressure in the central part, peripheral part and intermediate part of the work and in the retainer ring can be adjusted differently. Precision electronic regulators (31, 3
2, 33) are respectively connected to a central part and a peripheral part of the work (3) and a pressure sensor (not shown) for measuring a processing pressure generated when the retainer ring (21) is pressed against the polishing pad (28). I have. The precision electronic regulator (34) is connected to a pressure sensor (not shown) that measures a processing pressure generated when an intermediate portion of the work is pressed. Each pressure sensor is arranged between each precision electronic regulator and the balloon-like elastic body, measures the pressure of the fluid in the balloon-like elastic body, and compares the pressure of the fluid in the balloon-like elastic body experimentally obtained in advance. The processing pressure is calculated from the relational expression with the processing pressure.

Precision electronic regulators (31, 32, 33, 34)
Is preferably connected to the controller (35). The controller (35) controls the balance of the processing pressure in each part of the workpiece based on the processing pressure measured by the pressure sensor. Specifically, the controller (35) uses a precision electronic regulator (31,
Based on the processing pressure information transmitted via (32, 33, 34), an instruction is given to each precision electronic regulator to obtain a predetermined processing pressure balance. The precision electronic regulators (31, 32, 33, 34) adjust the pressure of the compressed air based on instructions from the controller (35).

Next, the operation of the work holding mechanism of the present invention described with reference to FIGS. 2 and 3 will be described below. First, using a precision electronic regulator (33), low-pressure compressed air (for example, 4.9 kPa-Gauge (0.05 kgf / cm ² -Gaug)
e)) Elastic sheet constituting the balloon-like elastic body in (23)
By expanding the retainer ring (21) in the pressing direction, the surface of the retainer ring (21) protrudes below the surface of the lip seal (18). Set the surface of 21) below the surface of the work. Then, the work (3) is carried into the wafer holding portion of the work holding mechanism by the loading / unloading device (for example, a robot: not shown), the operation of the work holding mechanism is started, and the intermediate space (30) is evacuated. . As a result, the work (3) is attracted to the center holding sheet (14) and the lip seal (18).

After the loading / unloading device is retracted, the work (3)
Is located above the polishing pad (28). Then, using a precision electronic regulator (33), the elastic sheet (23) of the balloon-like elastic body is inflated with low-pressure compressed air (for example, 9.8 kPa-Gauge (0.1 kgf / cm ² -Gauge)) to retain the ring. (21) is moved until its surface contacts the polishing pad (28). When the retainer ring (21) comes into contact with the polishing pad (28), the retainer ring (21) is pushed upward by the polishing pad (28) and rises slightly (for example, 0.01 mm).

Next, the intermediate space is positively pressured (for example, 9.8 kPa-Gauge (0.
1kgf / cm ² -Gauge) while being controlled), the compressed air that is controlled by precision electronic regulator (31, 32) (eg ^{9.8kPa-Gauge (0.1kgf / cm 2} -Gauge)) balloon-like elastic The workpiece (3) is supplied to the space (100, 102) of the body and pressed against the polishing pad (28). By this operation, the work (3) and the retainer ring are both pressed by the polishing pad (28), and the pressing is balanced.

Subsequently, the work (3) is put on the polishing pad (28).
Move relative to. As a method of relatively moving the work (3) with respect to the polishing pad (28), there is a method of performing an eccentric small circular motion (or orbital motion) of the platen (29) to which the polishing pad is attached. The revolution diameter and speed of the eccentric small circular motion are determined according to the type of the work and the polishing pad. For example, the revolving diameter is 5m
The platen (29) can be driven using a driving device (not shown) with the relative speed of 1000 mm / sec.

The relative speed of the work (3) is gradually increased (for example, for 10 seconds) from the start of the movement to a predetermined value. While increasing the speed, the balance controller (35) controls the pressure balance to a preset value,
The precision electronic regulator (31, 32, 33, 34) adjusts the pressure of the compressed air to a predetermined pressure (for example, about 39.2 kPa-Gauge).
(0.4 kgf / cm ² -Gauge)). Thereby,
Work (3) surface (polished surface) and retainer ring (2
The polishing process proceeds while the surface of 1) is held on the same surface.

The polishing rate (polishing amount per unit time) of the work (3) is determined by the processing pressure and the relative speed. Therefore, during polishing, precision electronic regulator (31)
Adjusts the pressure of the compressed air supplied to the space (100) of the balloon-like elastic body to determine the polishing rate at the center of the work (3). The precision electronic regulator (32) adjusts the pressure of the compressed air supplied to the space (102) of the balloon-shaped elastic body to determine the polishing rate of the peripheral portion of the work (3). The precision electronic regulator (34) is located in the intermediate space (3
By adjusting the pressure supplied to 0), the polishing rate of the intermediate portion of the work (3) is determined.

The precision electronic regulator (33) adjusts the pressure of the compressed air supplied to the space (104) of the balloon-like elastic body, and the retainer ring (21) adjusts the polishing pad (28).
To control the pressure applied to When the retainer ring (21) is pressed, the compression deformation state of the polishing pad (28) at the outer edge of the work (3) changes. Therefore, by changing the pressure applied by the retainer ring (21) to the polishing pad (28), the polishing rate of the outer edge of the work (3) can be changed.

The balance controller (35) controls the precision electronic regulators (31, 32, 33, 34) to change the pressure balance. By changing the pressure balance, it is possible to change the polishing rate of the central portion, the peripheral portion, the intermediate portion and the outer edge of the work (3), and consequently the polishing profile. The polishing profile is preferably changed so that the work surface is polished uniformly.

During polishing, the central portion and the peripheral portion of the work (3) are pressed against the polishing pad (28) by the pressing plate (13) and the pressing base (17), and are directly pressed by the compressed air. Department only. Therefore, as compared with the conventional holding mechanism as described with reference to FIG. 1, the leakage of air is extremely suppressed, so that the processing pressure can be made more uniform, and the agglomeration of the abrasive grains due to the drying of the polishing liquid can be prevented. Is suppressed. Further, since the pressing plate, the pressing base, and the retainer ring are held by the diaphragm, even if the positional interval changes or the inclination occurs between the holding mechanism (10) and the polishing pad (28), they are not changed by the diaphragm. It is corrected, so that the pressure balance is unlikely to change.

During polishing, the retainer ring (21) is pressed against the polishing pad (28) so that the work (3) is
Rattle is prevented. The work (3) does not jump out of the work holding head.

As shown in FIG. 7, the work holding mechanism (10) allows the work holding mechanism (10) to hold the polishing pad ( Even if frictional force is applied to the retainer ring (21) when moving in the horizontal direction relative to 28), the diaphragm (22) does not buckle, and thus the horizontal displacement of the retainer ring (21) Is prevented.
Also, even if the retainer ring (21) moves in the pressing direction,
Since the claw-like portions (22c, 22d) of the diaphragm are deformed to release the force that largely deforms the flexure portion of the diaphragm (22), local permanent deformation of the diaphragm is avoided.

Further, during polishing, for example, the work (3) is displaced in the horizontal direction due to frictional force and the retainer ring (21) is displaced.
By contact with the retaining ring (21)
The retainer ring (21) is not largely displaced in the horizontal direction even if a force is applied to displace a part of the retainer ring (21) in the horizontal direction due to the frictional force applied to the retainer ring (21). This is because the retainer ring (21) is held around the entire circumference by an annular diaphragm (22) having an axisymmetric structure with the rotation axis of the work holding mechanism as a symmetric axis. That is, even if such a force is applied to the retainer ring (21), the diaphragm (22) is elastically deformed, and a force in the opposite direction to the force with respect to the axis of symmetry can be applied to the retainer ring (21). The retainer ring (21) does not significantly displace in the horizontal direction, and the center of the retainer ring (21) can always coincide with the center of the work holding mechanism (10).

When the polishing process is completed, the relative movement of the work (3) with respect to the polishing pad (28) is stopped, and at the same time, the work (3) and the retainer ring (21) are set to a low pressure (for example, 4.9 kPa-Gauge (0. 05kgf / cm ² -Ga
controller) (35) and precision electronic regulators (31, 32,
33, 34) controls the pressure. Thereby, the holding mechanism (1
0), while slightly pressing the work (3) against the polishing pad (28), finally rises to a position where the work loading / unloading device can be operated.

The operation of the work holding mechanism described above is merely an example, and the method of loading and unloading the work, the pressure of the compressed air, and the like are appropriately selected according to the type of the work and the polishing pad.

Next, a second embodiment of the work holding mechanism of the present invention will be described with reference to FIG. 4, the same reference numerals as those used in FIG. 2 represent the same members as those represented in FIG.

In the work holding mechanism shown in FIG. 4, a fluid pipe (38) is provided on the pressing plate (13). The fluid conduit (38) extends from the back surface of the pressing plate (13) over a part of the thickness, bends in the middle, and extends in the radial direction.
Therefore, the ports (39a, 39b) of the fluid conduit (38)
Are located on the back and side surfaces of the pressing plate (13). The port (39a) of the fluid conduit is connected to the fluid conduit (37), and the port (39b) is open to the intermediate space (30). The fluid supplied to the intermediate space (30) is formed between the pressure plate (13), the elastic sheet of balloon-like elastic material (15), and the work holding base (11) from the fluid conduit (37). Through the gap, and further through the fluid conduit (38).

In FIG. 4, when the fluid is supplied and expanded, the elastic sheet (15) constituting the balloon-like elastic body comes into contact with the pressing plate (13) and the pressing plate (13) of the fluid pipe (38). ) Is closed on the port (39a) located on the back side. When the balloon-shaped elastic sheet (15) closes the port (39a), the fluid cannot be supplied to the intermediate space (30).

In the illustrated embodiment, the diaphragm (16) holding the pressing plate (13) is fixed to the holding base (11). The diaphragm (20) holding the pressing base (17) is annular, and its outer peripheral portion is a retainer ring (2).
Fixed to 1). Other configurations are the same as those shown in FIG.

The operation of the work holding mechanism shown in FIG.
This will be described below while clarifying points different from the operation of the work holding mechanism shown in FIG.

The work (3) is attracted to the center holding sheet (14) and the lip seal (18) by evacuating the intermediate space (30) as in the case of using the work holding mechanism shown in FIG. Is done. The lowering of the retainer ring (21) is performed in the same manner as described above using the precision electronic regulator (33).

Next, compressed air (for example, 9.8 kPa-Gauge) pressure-controlled by precision electronic regulators (31, 32)
(0.1 kgf / cm ² -Gauge)) is supplied to the space (100, 102) of the balloon-like elastic body, and the center and the periphery of the work (3) are pressed against the polishing pad (28). By this operation, the work (3) and the retainer ring (21) are both pressed against the polishing pad (28), and the processing pressure is balanced. However, an elastic sheet of balloon-like elastic material (15)
Expands to close the port (39a) of the fluid conduit (38), so that the intermediate space (30) and the peripheral edge of the pressing plate (13) maintain the pressure at the time of evacuation (ie, , Reduced pressure state). Therefore, the pressing plate (13) works so that the center of the work (3) is convex downward.
Is pressed against the polishing pad (28). When the work is pressed in this way, the processing pressure at the center can be increased, so that when the processing pressure at the peripheral portion is larger than the processing pressure at the center, the processing pressure can be made uniform over the entire surface of the work. .

The method of moving the work (3) relative to the polishing pad (28) and the operation when the work is polished are the same as those described with reference to FIGS. However, when the work holding mechanism shown in FIG. 4 is used, the pressure in the intermediate space (30) cannot be controlled by the precision electronic regulator (34) when the port (39a) is closed. Therefore, the intermediate space (3
It is necessary to control the pressure of the fluid in 0) with the elastic sheet (15) of the balloon-like elastic body separated from the port (39a).

Next, a third embodiment of the work holding mechanism of the present invention will be described with reference to FIG. 5, the same reference numerals as those used in FIG. 2 denote the same members as those represented in FIG.

In the work holding mechanism shown in FIG. 5, a part of the work pressing plate (13) and the diaphragm (16) and a part of the pressing base (17) and the diaphragm (20) shown in FIG. A diaphragm (40) is provided which is partially different. In the diaphragm (40), portions (40a, 40a) corresponding to the pressing plate and the pressing base
b) has a large thickness, for example, about 5 mm.
In the diaphragm (40), the thick part (40
a, 40b) to bend so as to move them in the pressing direction (40, 40b).
c) has a small thickness, for example about 0.2 mm. Such a diaphragm (40) is made of a thick plate-like member (for example, about 5 m thick) made of SUS or Hastelloy.
m) and a thin plate-shaped member (for example, about 0.2 mm thick) can be formed by bonding, for example, by diffusion bonding.

The pressure plates (400a, 400b) are placed on the thick portions (40a, 40b) of the diaphragm (40), respectively.
b) is arranged. The pressure plates (400a, 400b) transmit the pressure of the fluid supplied to the space portions (100, 102) of the balloon-like elastic body to the diaphragm (40). Press plate (400
a, 400b) are fixed to the diaphragm (40) by, for example, bolting. The pressing plates (400a, 400b) correspond to the upper portion (13a) of the pressing plate (13) and the upper portion (17a) of the pressing base in FIG. 2, and can be said to be a part of the pressing plate and the pressing base. In the above diaphragm (40)
Is provided in place of the "part" of the pressing plate (13) and the pressing base (17) for that reason.

In the illustrated embodiment, the periphery of the diaphragm (40) is fixed to the retainer ring (21). Other configurations are the same as those shown in FIG. The work holding mechanism can be used according to the same method as the work holding mechanism shown in FIG.

The work holding mechanism shown in FIGS. 2 to 5 exemplifies the embodiments of the present invention, and the scope of the present invention is not limited to these embodiments. Further, some of these embodiments may be changed as necessary.

[0132]

As described above, in the work holding mechanism of the present invention, the work pressing mechanism is constituted by the balloon-like elastic body, the diaphragm and the pressing plate. The pressing mechanism is characterized in that the work is pressed against the polishing pad via the pressing plate by expanding the balloon-like elastic body by the pressure of the fluid supplied into the balloon-like elastic body. According to such a pressing mechanism, leakage of the fluid can be effectively prevented, so that the processing pressure can be made uniform over the entire work and scratches caused by agglomeration of abrasive grains can be reduced, thereby improving the yield of the work. be able to.

If a plurality of the pressing mechanisms are provided, the work can be pressed differently in a plurality of sections. Therefore, the processing pressure can be optimally distributed according to the workpiece. Further, even if the warpage of the work changes from lot to lot, the polishing rate of the work can be easily controlled so as to be suitable for the work without replacing the retainer ring or the like.

Further, when the retainer ring is pressed against the polishing pad independently, the compression deformation state of the polishing pad at the outer edge of the work can be changed. as a result,
Edge dripping of the work can be further suppressed, and the yield of the work can be further improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a conventional work holding mechanism.

FIG. 2 is a sectional view schematically showing a first embodiment of the work holding mechanism of the present invention.

FIG. 3 is a schematic diagram showing a control flow of compressed air in the work holding mechanism of the present invention.

FIG. 4 is a sectional view schematically showing a second embodiment of the work holding mechanism of the present invention.

FIG. 5 is a sectional view schematically showing a third embodiment of the work holding mechanism of the present invention.

FIG. 6 is a perspective view schematically showing a diaphragm for holding a retainer ring in the work holding mechanism of the present invention.

FIG. 7 is a cross-sectional view schematically illustrating an example of a holding form of a retainer ring in the work holding mechanism of the present invention.

[Description of Signs] 3 ... Work (semiconductor wafer), 10 ... Work holding mechanism,
11 ... holding base, 12 ... rotary shaft, 13 ... press plate, 14 ...
Central holding sheet, 15 ... elastic sheet, 16 ... diaphragm, 17 ... pressing base, 18 ... lip seal, 19 ... elastic sheet, 20 ... diaphragm, 21 ... retainer ring , 2
2 ... diaphragm, 23 ... elastic sheet, 24 ... holding plate, 2
5 ... plate-like member, 26 ... fluid line, 27 ... fluid line, 2
8 ... polishing pad, 29 ... surface plate, 30 ... intermediate space, 31,3
2, 33, 34 ... precision electronic regulator, 35 ... controller, 36 ... fluid line, 37 ... fluid line, 38 ... fluid line, 39a, 39b ... .Port, 40 ... diaphragm, 10
0, 102, 104 ... space, 400 ... press plate, 41 ... surface plate, 4
2 ... Polishing pad, 43 ... Substrate, 44 ... Substrate holding device, 4
5 ... Rotating shaft part, 46 ... Substrate holding head, 47 ... Lip seal, 48 ... Retainer ring, 49 ... Fluid flow passage, 50 ... Space part.

Continuation of the front page (72) Inventor Katsuyoshi Shingu 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. (reference) 3C058 AA07 AB04 BA05 BB04 BC01 CA06 CB01 CB03 CB04 DA17

Claims (34)

[Claims] 1. A work holding mechanism for pressing a work against a polishing pad and holding the work in a plane perpendicular to the pressing direction, the work holding mechanism comprising: one or a plurality of pressing plates in contact with at least a part of a back surface of the work; A diaphragm for holding the pressing plate movably in the pressing direction, and a balloon-like elastic body capable of contacting the back surface of each pressing plate are provided, and the balloon-like elastic body expands due to the pressure of the fluid supplied into the balloon-like elastic body. A work holding mechanism in which at least a part of the surface of the work is pressed against the polishing pad via the pressing plate. 2. A holding sheet in contact with at least a part of the back surface of the work is attached to at least a part of the surface of the pressing plate, and at least a part of the surface of the work is pressed against the polishing pad via the pressing plate and the holding sheet. The work holding mechanism according to claim 1. 3. The method according to claim 1, wherein one pressing plate is in contact with substantially the entire back surface of the work, and substantially the entire front surface of the work is pressed against the polishing pad via the pressing plate. Work holding mechanism. 4. A holding sheet in contact with substantially the entire back surface of the work is attached to the pressing plate surface, and substantially the entire surface of the work is pressed against the polishing pad via the pressing plate and the holding sheet. Item 4. A work holding mechanism according to Item 3. 5. A work holding mechanism for pressing a work to a polishing pad and holding the work in a plane perpendicular to the pressing direction, the work holding mechanism comprising: one or a plurality of pressing plates in contact with a back surface of a central portion of the work; A diaphragm for holding the plate so as to be movable in the pressing direction, a balloon-like elastic body capable of contacting the back surface of each pressing plate, and a pressing base contacting the back surface of the peripheral portion of the work not contacting the pressing plate; When the balloon-like elastic body expands due to the pressure of the fluid supplied into the body, the surface of the central portion of the work is pressed against the polishing pad via the pressing plate, and the surface of the peripheral portion of the work is polished via the pressing base. Work holding mechanism pressed by the pad. 6. A diaphragm for holding a pressing base movably in a pressing direction, and a balloon-like elastic body capable of contacting a back surface of the pressing base, wherein the balloon-like elastic body is pressed by a fluid supplied into the balloon-like elastic body. The work holding mechanism according to claim 5, wherein the surface of the peripheral portion of the work is pressed against the polishing pad via the pressing base by expanding the work. 7. A central holding sheet which is in contact with at least a part of a back surface of a central portion of the work is attached to at least a part of a surface of the pressing plate, and a peripheral holding sheet which is in contact with at least a part of a back surface of a peripheral portion of the work is a pressing plate. Attached to at least a part of the base surface, at least a part of the surface of the central portion of the work is pressed against the polishing pad via the pressing plate and the center holding sheet, and the work piece is pressed via the pressing base and the peripheral holding sheet. 7. The work holding mechanism according to claim 5, wherein at least a part of the surface of the peripheral portion is pressed against the polishing pad. 8. The work holding mechanism according to claim 5, wherein a diaphragm for holding the pressing plate movably in the pressing direction is attached to the pressing base. 9. The work holding mechanism according to claim 1, wherein a space is formed in contact with a part of the back surface of the work when the work is held. 10. The work holding mechanism according to claim 9, wherein the fluid is independently supplied to a space formed when the work is held and in contact with a part of the back surface of the work. 11. The work holding mechanism according to claim 9, wherein the space formed when the work is held and in contact with a part of the back surface of the work can be evacuated. 12. The work holding mechanism according to claim 9, wherein the pressing plate is in contact with the work in a lip seal shape at an outer edge of the work. 13. The work holding mechanism according to claim 9, wherein the pressing base is in contact with the work in a lip seal shape at an outer edge of the work. 14. A fluid conduit extending from the back surface of the pressure plate and penetrating the pressure plate is further provided.
The work holding mechanism according to any one of the above. 15. The work holding mechanism according to claim 14, wherein the fluid conduit penetrates from a back surface of the pressing plate to a surface of the pressing plate. 16. A port on the back surface of the pressure plate of the fluid conduit is closed by the balloon-like elastic body when fluid is supplied into the balloon-like elastic body and the balloon-like elastic body expands. A work holding mechanism according to claim 14 or claim 15. 17. A diaphragm having a partially different thickness instead of a part or all of one or more pressing plates and a diaphragm for holding the pressing plate movably in a pressing direction, wherein the diaphragm has a partially different thickness. The work holding mechanism according to any one of claims 1 to 16, further comprising a diaphragm that contacts at least a part thereof. 18. A diaphragm having a thickness that is partially different from a part or all of one or more pressing bases and a diaphragm that movably holds the pressing base in a pressing direction, wherein the diaphragm has a peripheral edge portion of a workpiece. The workpiece holding mechanism according to any one of claims 1 to 17, wherein a diaphragm is provided in contact with a back surface of the workpiece. 19. The work holding mechanism according to claim 1, further comprising a holding member surrounding an outer edge of the work. 20. The work holding mechanism according to claim 19, further comprising a diaphragm for holding the holding member movably in the pressing direction, and a pressing means for pressing the holding member against the polishing pad. 21. A balloon-like elastic body which is capable of contacting the back surface of the holding member is provided as a pressing means. The work holding mechanism according to claim 20, which is pressed. 22. The diaphragm according to claim 20, wherein the diaphragm for holding the holding member movably in the pressing direction has an annular shape, the outer peripheral portion is supported by the holding base, and the inner peripheral portion is supported by the holding member. 22. The work holding mechanism according to 21. 23. A plurality of holes are formed along the circumference at an inner peripheral portion and an outer peripheral portion of the diaphragm for holding the holding member so as to be movable in the pressing direction, and the holding member and the holding base are respectively provided with concave portions. 23. The work holding mechanism according to claim 22, further comprising two members having a projection and a projection, wherein the projection is fitted into the recess through a hole formed in the diaphragm, whereby the hole of the diaphragm is sandwiched. 24. A claw-shaped protrusion protruding in the radial direction of the diaphragm is provided on an inner periphery and / or an outer periphery of a hole formed in a diaphragm for holding a holding member so as to be movable in a pressing direction. 24. The work holding mechanism according to claim 23, wherein the support elastically supports the protrusions of the holding member and the holding base in a radial direction. 25. The projection of the holding member is supported by a projection formed on one of the inner periphery and the outer periphery of the hole, and the projection of the holding base is opposite to the projection supporting the projection of the holding member. 25. The work holding mechanism according to claim 24, wherein the work holding mechanism is supported by a protruding portion formed on a side periphery. 26. The work holding mechanism according to claim 19, wherein a diaphragm for holding the pressing plate movably in the pressing direction is attached to the holding member. 27. The work holding mechanism according to claim 19, wherein a diaphragm for holding the pressing base movably in the pressing direction is attached to the holding member. 28. The groove according to claim 1, wherein a groove is formed on the surface of the pressing plate, and a substantially sealed fluid conduit is formed between the groove and the work when the work is held. 2. The work holding mechanism according to claim 1. 29. A groove is formed on the surface of the pressing base,
The work holding mechanism according to any one of claims 5 to 28, wherein a substantially sealed fluid conduit is formed between the groove and the work when the work is held. 30. An apparatus for polishing a surface to be polished of a work with a polishing pad, comprising: a) a work holding mechanism according to any one of claims 1 to 29; b) a surface plate supporting the polishing pad; And c) a polishing apparatus having means for moving the work relative to the polishing pad. 31. A method of polishing a work by pressing a surface to be polished of the work against a polishing pad and moving the work relative to the polishing pad, wherein the pressing plate is indirectly displaced by the pressure of a fluid. A pressing plate for pressing at least a part of the back surface of the work, thereby pressing at least a part of the polished surface of the work to a polishing pad. 32. A pressing plate is movably held in a pressing direction by a diaphragm, and a fluid is supplied to a balloon-like elastic body provided on a back surface of the pressing plate to expand the balloon-like elastic body, thereby displacing the pressing plate. The polishing method according to claim 31, wherein the polishing is performed. 33. The polishing method according to claim 31, wherein the back surface of the holding member surrounding the outer edge of the workpiece is indirectly pressed by the pressure of the fluid, whereby the holding member is pressed against the polishing pad. Method. 34. A holding member is movably held in a pressing direction by a diaphragm, and a fluid is supplied to a balloon-like elastic body provided on a back surface of the holding member to expand the balloon-like elastic body so that the back surface of the holding member is inflated. The polishing method according to claim 33, wherein the pressing is performed.