Polished object holding tool and polished object holding method

Abstract

To reduce running costs.SOLUTION: The invention relates to a holding tool 3 of a disc-like polished object 1 including: a holding pad 11 which is provided so as to be attachable to / detachable from a holding surface plate 4 and provided with a holding surface 11a for holding the polished object 1; and a ring-shaped frame member 12 which encloses the polished object 1 held by the holding surface 11a of the holding pad 11. The frame member 12 includes: a ring-shaped outer frame member 12A fixed to the holding pad 11; and a ring-shaped inner frame member 12B which is provided so as to be attachable to / detachable from the holding pad 11 and the outer frame member 12A at the inner side of the outer frame member 12A. A height of the outer frame member 12A is set to a height of the inner frame member 12B or lower.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a holder for a polished object and a method for holding a polished object, and more particularly to a holder for a polished object and a method for holding a polished object, which are provided with a holding pad that is detachably attached to a holding platen, and a ring-shaped frame member that surrounds the polished object held on the holding surface of the holding pad. [Background technology]

[0002] Conventionally, polishing apparatuses for polishing objects such as semiconductor devices have been known that include a holding platen for holding the object and a polishing platen for holding a polishing pad. The apparatus performs so-called chemical mechanical polishing (CMP) by supplying a slurry (polishing liquid) between the object and the polishing pad and sliding them together (Patent Documents 1 and 2). The holding platens described in Patent Documents 1 and 2 above are provided with a holder for holding the workpiece to be polished, and the holder includes a holding pad that is detachably attached to the holding platen and has a holding surface for holding a disk-shaped workpiece to be polished, and a ring-shaped frame member that surrounds the workpiece held on the holding surface of the holding pad. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-72801 A [Patent Document 2] Patent No. 7212242 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, the above-mentioned slurry may be strongly acidic or strongly alkaline, and may deteriorate the frame member while the workpiece is being polished by the polishing device. In particular, if the inner peripheral surface of the frame member is deteriorated by the slurry that has entered between the workpiece and the frame member, there is a risk of damaging the contact portion with the workpiece. As a result, even if the holding pad maintains its ability to hold the workpiece, the entire holder must be replaced due to deterioration of the frame-shaped member, resulting in high running costs. In view of the above problems, the present invention provides a holder for a polished object and a method for holding a polished object that can reduce running costs. [Means for solving the problem]

[0005] That is, the holder for a workpiece according to the invention of claim 1 is a holder for a workpiece comprising a holding pad which is detachably attached to a holding platen and has a holding surface for holding a disk-shaped workpiece, and a ring-shaped frame member which surrounds the workpiece held on the holding surface of the holding pad, the frame-shaped member includes a ring-shaped outer frame-shaped member fixed to the holding pad, and a ring-shaped inner frame-shaped member provided inside the outer frame-shaped member so as to be detachable from the holding pad and the outer frame-shaped member, The height of the outer frame member is set to be equal to or less than the height of the inner frame member. Furthermore, a method for holding a workpiece according to the invention of claim 5 is characterized in that, using a holder according to any one of claims 1 to 4, the holding pad is attached to a holding platen with the holding surface facing downward. Effect of the Invention

[0006] According to the above invention, when the inner surface of the inner frame-shaped member is deteriorated by slurry when the workpiece is polished by the polishing device, only the inner frame-shaped member can be removed and replaced with a new inner frame-shaped member. In other words, when the holding ability of the holding pad to hold the workpiece is maintained, only the inner frame member needs to be replaced, and the holding pad and the outer frame member can be used as they are, thereby making it possible to reduce the running costs of the entire holder. [Brief description of the drawings]

[0007] [Figure 1] Side view of the polishing device [Diagram 2] Plan view of the holder DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present invention will now be described with reference to the illustrated embodiment. FIG. 1 shows a side view of a polishing apparatus 2 for polishing an object to be polished 1, the object to be polished being a silicon wafer or a semiconductor device such as a semiconductor substrate, and the object to be polished 1 has a disk shape. The polishing apparatus 2 includes a holding platen 4 which holds the object to be polished 1 via a holder 3 according to the present invention, a polishing platen 6 which is positioned below the holding platen 4 and holds a polishing pad 5, and a slurry supply means 7 which supplies a slurry S (polishing liquid) between the object to be polished 1 and the polishing pad 5. The holding platen 4 and the polishing platen 6 each have a substantially disk shape, and are rotated by a driving means (not shown), and the holding platen 4 is provided so as to be movable up and down by a lifting means (not shown). The polishing pad 5 has a substantially disk shape and is fixed to the upper part of the polishing platen 6 by double-sided tape or the like. The diameter of the polishing pad 5 is larger than the diameter of the object 1 to be polished. When polishing the workpiece 1 using the polishing apparatus 2 having the above-mentioned configuration, the workpiece 1 is held on the holding platen 4 using the holder 3 so that the surface to be polished faces downward, and the holding platen 4 is lowered to press the workpiece 1 against the polishing pad 5. In this state, the holding platen 4 and the polishing platen 6 are rotated, and the slurry supply means 7 supplies slurry S to the upper surface of the polishing pad 5, so that the slurry S penetrates between the polishing pad 5 and the object to be polished 1, which are sliding against each other, and the surface of the object to be polished 1 is mechanically and chemically polished (CMP).

[0009] Hereinafter, a specific description will be given of the holder 3 provided on the holding platen 4. In this embodiment, the holder 3 is provided on the holding platen 4 in a replaceable manner, and is replaced every time a plurality of objects 1 to be polished are polished. The holder 3 includes a holding pad 11 that is removably mounted on the holding platen 4 and has a holding surface 11a for holding the workpiece 1, and a ring-shaped frame member 12 that surrounds the workpiece 1 held on the holding surface 11a of the holding pad 11. The holding pad 11 is not particularly limited as long as it is made of a material capable of holding the workpiece, but examples thereof include sheet-like polyurethane (also called a polyurethane sheet or a foamed polyurethane sheet) or a photocurable resin, and the upper surface of the holding pad 11 is adhered to the holding platen 4 with double-sided tape or the like. When the holder 3 is to be replaced, the holding pad 11 is removed from the holding platen 4 together with the holding pad 11. On the other hand, the holding surface 11a formed on the lower surface of the holding pad 11 faces downwards as a result of being attached to the holding platen 4, and when the workpiece 1 is held on the holding surface 11a, the surface to be polished faces downwards. Also, the workpiece 1 is attracted and held on the holding surface 11a by utilizing the surface tension of water or the like. As an example of the holding pad 11, in the case of a sheet-like polyurethane, multiple teardrop-shaped bubbles are formed inside, and the teardrop-shaped bubbles refer to bubbles formed inside the polyurethane sheet by the wet film-forming method (bubbles that are anisotropic and have a structure in which the diameter increases from the top of the resin sheet (the side in contact with the polished object 1) to the bottom). The wet film-forming method is a method in which the resin to be formed into a film is dissolved in an organic solvent, the resin solution is applied to a sheet-like substrate, and then the solution is passed through a coagulating liquid in which the organic solvent dissolves but the resin does not, to replace the organic solvent, coagulate the resin, and dry the solution to form a foam layer.

[0010] There is no particular limitation on the type of polyurethane resin constituting the holding pad 11, and it may be selected from various polyurethane resins according to the intended use. For example, polyester-based, polyether-based, polycarbonate-based, or a mixture thereof resin may be used. Examples of polyester resins include polymers of polyester polyols such as ethylene glycol or butylene glycol and adipic acid, and diisocyanates such as diphenylmethane-4,4'-diisocyanate. Examples of polyether-based resins include polymers of polyether polyols, such as polytetramethylene ether glycol and polypropylene glycol, and isocyanates, such as diphenylmethane-4,4'-diisocyanate. Examples of polycarbonate-based resins include polymers of polycarbonate polyol and isocyanates such as diphenylmethane-4,4'-diisocyanate. Other examples of materials for the holding pad 11 include photocurable resins. The photocurable resins are not particularly limited as long as they are polymerized and cured by light of a specific wavelength, but include photosensitive resins, ultraviolet-curable resins, and visible-light-curable resins. In addition, radical-polymerizable resins that are cured by radicals activated by light, and cationic-polymerizable resins that are cured by cations generated by light are also included. Preferred embodiments include polyester-based resins, unsaturated polyester-based resins, vinyl ether resins, vinyl ester resins, acrylic resins, and epoxy-based resins. More preferably, acrylic resins and epoxy resins are included. The resins may be used alone or in combination of two or more types. By using these resins, the surface shape can be easily manufactured, and the resins have chemical resistance, improving resistance to strong acidic and strong alkaline slurries. These resins may be commercially available resins such as those available under the trade name "Crisbon" manufactured by DIC Corporation, "Sanpren" manufactured by Sanyo Chemical Industries, Ltd., "Rezamin" manufactured by Dainichi Seikagaku Kogyo Co., Ltd., "Cosmolite" manufactured by Toyobo Co., Ltd., "PG Plate" manufactured by Toray Industries, Inc., and "Fuji Treleaf" manufactured by Fuji Film Corporation, or resins having the desired properties may be manufactured by the manufacturer. The holding surface 11a of the holding pad 11 may or may not have been subjected to a grinding process such as buffing, but if it has not been subjected to a grinding process, the adhesion to the workpiece 1 is improved, thereby reducing lateral shifting of the workpiece 1 that occurs during the polishing process, which is preferable.

[0011] As shown in FIG. 2, the frame member 12 includes a ring-shaped outer frame member 12A fixed to the holding pad 11, and a ring-shaped inner frame member 12B provided inside the outer frame member 12A. There are no specific regulations regarding the radial widths of the outer frame member 12A and the inner frame member 12B, but the outer frame member 12A must be wide enough to hold the inner frame member 12B and the workpiece 1 located on the inside so that they do not fall off during polishing, and the inner frame member 12B must be wide enough to allow at least one polishing session using the polishing device 2.

[0012] Materials that can be used for the outer frame member 12A and the inner frame member 12B include rigid materials such as fiber-reinforced resins such as glass fiber-reinforced epoxy resins and metals such as stainless steel, as well as ABS resins, polyvinyl chloride resins, and polyetherimide resins. Furthermore, the materials used for the outer frame member 12A and the inner frame member 12B may be the same or different. When they are different, it is preferable that the D hardness of the material of the outer frame member 12A is 10 to 30 degrees higher than the D hardness of the inner frame member 12B. The hardness of each of the outer frame member 12A and the inner frame member 12B is not particularly limited, but the preferred range for the D hardness of the outer frame member 12A is 50 to 80 degrees, more preferably 55 to 78 degrees, and even more preferably 60 to 75 degrees, and the preferred range for the D hardness of the inner frame member 12B is 40 to 70 degrees, more preferably 45 to 70 degrees, and even more preferably 50 to 70 degrees. This makes it possible to easily fix the inner frame member 12B and the object to be polished, and also provides the effect of extending the life of the outer frame member 12A. However, it is preferable to use a material that does not contain reinforcing fibers for the inner frame member 12B. This is because if the inner frame member 12B is deteriorated by the slurry S and the reinforcing fibers are exposed on the inner peripheral surface of the inner frame member 12B, the polished object 1 may be damaged.

[0013] As shown in FIG. 1, in the holder 3 of this embodiment, the height of the outer frame member 12A relative to the holding pad 11 is lower than the height of the inner frame member 12B, and the height of the inner frame member 12B is lower than the height (thickness) of the object 1 to be polished. The outer frame member 12A is a ring-shaped member provided along the outer peripheral edge of the holding pad 11, and its upper surface is fixed to the holding surface 11a of the holding pad 11 by means of adhesion or the like so that it does not come off. The outer diameter of the inner frame member 12B is the same as the inner diameter of the outer frame member 12A, and the inner frame member 12B is fitted inside the outer frame member 12A to be detachable. The mating portion may or may not have projections and recesses so that they can be removed after mating, but it is preferable that the mating portion has a shape without projections and recesses. If no projections and recesses are formed, the inner frame member 12B is held to the outer frame member 12A by frictional force. The upper surface of the inner frame member 12B is formed to be smooth, so that the inner frame member 12B is attracted and held by the holding pad 11 also by the surface tension of water. With this configuration, the inner frame member 12B is removably held relative to the outer frame member 12A and the holding pad 11. In this invention, "removable" refers to a configuration in which the inner frame member 12B can be held without using mechanical fixing means such as screws or adhesives, and further without creating any irregularities that would make removal difficult when the inner frame member 12B is engaged. In other words, by holding the inner frame member 12B without using any additional mechanical fixing means such as screws, the workability of manufacturing the holder 3 and replacing the inner frame member 12B is improved, and by not using adhesives, etc., the adhesive will not melt or peel off during polishing, reducing the impact of polishing. Furthermore, by not providing any recesses or projections for engagement that would make removal difficult once engaged, the recesses and projections are not damaged by stress during polishing or replacement, and the life of the entire holder 3 can be extended. Here, the inner peripheral surface of the outer frame member 12A and the outer peripheral surface of the inner frame member 12B may be tapered to facilitate fitting the inner frame member 12B into the outer frame member 12A. In Figures 1 and 2, the inner diameter of the inner frame member 12B is larger than the outer diameter of the workpiece 1, and a gap is formed between them, but the inner diameter of the inner frame member 12B may be the same as the workpiece 1, so that no gap is formed between them.

[0014] 1, the height of the outer frame member 12A relative to the holding pad 11 is lower than the height of the inner frame member 12B. The height of the inner frame member 12B is also lower than the height (thickness) of the object 1 to be polished. With this configuration, in the polishing apparatus 2 of this embodiment, when the holding platen 4 holds the workpiece 1, the surface to be polished faces downward, and the lower surface of the workpiece 1 protrudes downward beyond the lower surface of the inner frame member 12B, which protrudes downward beyond the lower surface of the outer frame member 12A. Here, it is preferable to set the height of the inner frame member 12B to be greater than the difference in height h between the outer frame member 12A and the object 1 to be polished, and it is preferable that the difference in height h' between the outer frame member 12A and the inner frame member 12B is in the range of 5 to 90% of the height of the outer frame member 12A, more preferably in the range of 8 to 80%, and further preferably in the range of 10 to 70%. Moreover, it is preferable to set the height of the outer frame member 12A within the range of 50 to 95% of the height of the inner frame member 12B, more preferably within the range of 55 to 93%, and further preferably within the range of 60 to 90%. The heights of the outer frame member 12A are not particularly limited, but preferred ranges are 100 to 470 μm, more preferably 130 to 450 μm, and even more preferably 150 to 430 μm; the height of the inner frame member 12B is 200 to 500 μm, more preferably 260 to 480 μm, and even more preferably 300 to 450 μm; and the height of the workpiece to be polished is 450 to 600 μm, more preferably 455 to 580 μm, and even more preferably 460 to 550 μm. By setting the heights of the outer frame member 12A and the inner frame member 12B in this manner, it is possible to prevent the inner frame member 12B from falling off the outer frame member 12A during polishing by the polishing apparatus 2 as much as possible. Furthermore, by making the height of the outer frame member 12A lower than the workpiece and the inner frame member 12B, the outer frame member 12A is less likely to come into contact with slurry or a polishing pad during polishing than the inner frame member 12B. This reduces wear and damage to the outer frame member 12A caused by slurry and polishing pads, making it possible to use the outer frame member 12A for a long period of time, thereby resulting in a longer life for the entire holder 3.

[0015] A method of using the polishing device 2 equipped with the holder 3 having the above-described configuration will now be described. First, the holder 3 and the object to be polished 1 are mounted on the holding platen 4. The outer frame member 12A of the holder 3 is fixed to the holding pad 11, and the inner frame member 12B is fitted inside the outer frame member 12A. In this state, when the workpiece 1 is held on the holding pad 11 of the holder 3, the surface to be polished of the workpiece 1 is held facing downward, and at this time, the underside of the workpiece 1 protrudes downward beyond the underside of the inner frame member 12B, and further, the underside of the inner frame member 12B protrudes downward beyond the underside of the outer frame member 12A. Thereafter, the holding platen 4 is lowered to press the workpiece 1 against the polishing pad 5 fixed to the polishing platen 6, and in this state, the holding platen 4 and the polishing platen 6 are rotated while the slurry supplying means 7 supplies slurry S between the workpiece 1 and the polishing pad 5, thereby causing the workpiece 1 to be polished by the polishing pad 5.

[0016] When polishing of the object 1 is completed in this manner, the object 1 is removed from the holder 3 and a new object 1 is attached to the holder 3, and polishing of the new object 1 is repeated. When a plurality of objects 1 to be polished are polished in this manner, the outer frame member 12A and the inner frame member 12B constituting the holder 3 are deteriorated by the slurry S having strong acidity or strong baseness. In particular, if the slurry S gets into the gap between the workpiece 1 and the inner frame member 12B, the inner surface of the inner frame member 12B will deteriorate, and there is a risk that the unevenness formed by the deterioration will cause scratches on the workpiece 1. Therefore, although it becomes necessary to replace the frame member 12B due to deterioration caused by the slurry S, the holding pad 11 maintains its holding performance and may even be in a state capable of withstanding multiple uses.

[0017] Furthermore, in the case of the holder 3 of this embodiment, since the lower surface of the outer frame member 12A is located higher than the lower surface of the inner frame member 12B, adhesion of the slurry S to the outer frame member 12A during polishing is suppressed. For this reason, the outer frame member 12A is less deteriorated than the inner frame member 12B, and since it does not come into contact with the workpiece 1, it can be used as is even if it is slightly deteriorated. Therefore, when the inner frame member 12B is deteriorated by the slurry S, it is sufficient to replace only the inner frame member 12B that is in contact with the workpiece 1 to be polished, without replacing the entire holder 3. At this time, since the inner frame member 12B is not adhered to the outer frame member 12A and the holding pad 11, only the inner frame member 12B can be easily removed, and a new inner frame member 12B can be easily attached. Thereafter, polishing of the object 1 is continued, and when the holding ability of the holding pad 11 decreases, the holding pad 11 is then removed from the holding platen 4 and a new holder 3 is attached to the holding platen 4 .

[0018] As described above, according to the holder 3 of this embodiment, when the inner frame member 12B is deteriorated by the slurry S, only the inner frame member 12B needs to be replaced, and the usable holding pad 11 and the outer frame member 12A that does not contact the workpiece 1 can be used as is, thereby keeping the overall running costs of the holder 3 low. In contrast, in the case of conventional holders, if the inner surface of the frame-shaped member that contacts the workpiece 1 deteriorates, the frame-shaped member and the holding pad that make up the holder must all be replaced, resulting in relatively high running costs.

[0019] In the polishing apparatus 2 of the above embodiment, the holding platen 4 is located above the polishing platen 6, and the polished surface of the workpiece 1 held by the holder 3 faces downward, but the holder 3 of the present invention can also be used in a polishing apparatus 2 having the holding platen 4 located below. In this case, the slurry S supplied by the slurry supply means 7 will adhere to the entire holder 3 located below, i.e., the outer frame member 12A, but even in this case, only the inner frame member 12B that comes into contact with the workpiece 1 needs to be replaced. In addition, in the above embodiment, the outer frame member 12A is made lower than the inner frame member 12B so that the inner frame member 12B protrudes more than the outer frame member 12A, but the outer frame member 12A and the inner frame member 12B may be made the same height. Even in this case, if the inner peripheral surface of the inner frame member 12B is deteriorated by the slurry S that has entered between the workpiece 1 and the inner frame member 12B, it is sufficient to replace only the inner frame member 12B. [Explanation of symbols]

[0020] 1 Object to be polished 2 Polishing device 3 Holding tool 4 Holding plate 5 Polishing pad 6 Polishing plate 7 Slurry supply means 11 Holding pad 12 Frame-shaped member 12A Outer frame-shaped member 12B Inner frame member S Slurry

Claims

1. A holder for a workpiece includes a holding pad that is detachably attached to a holding platen and has a holding surface for holding a disk-shaped workpiece, and a ring-shaped frame member that surrounds the workpiece held on the holding surface of the holding pad, the frame-shaped member includes a ring-shaped outer frame-shaped member fixed to the holding pad, and a ring-shaped inner frame-shaped member provided inside the outer frame-shaped member so as to be detachable from the holding pad and the outer frame-shaped member, A holder for a polished workpiece, characterized in that the height of the outer frame member is equal to or less than the height of the inner frame member.

2. 2. A holder for a workpiece as claimed in claim 1, wherein the height of the outer frame member is less than the height of the inner frame member.

3. 3. The holder for a polished workpiece according to claim 2, wherein the height of the outer frame member is in the range of 50 to 95% of the height of the inner frame member.

4. 2. The holder for a workpiece according to claim 1, wherein the height of the inner frame member is made larger than the difference in height between the outer frame member and the workpiece.

5. 5. The method for holding a workpiece using a holder according to claim 1, wherein the holding pad is attached to a holding platen with the holding surface facing downward.

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