US20140004780A1

US20140004780A1 - Method of manufacturing polishing pad mold, polishing pad mold manufactured by the method, and polishing pad manufactured by the mold

Info

Publication number: US20140004780A1
Application number: US13/921,821
Authority: US
Inventors: Yasunori Tashiro; Masato Takata; Toshiaki Atari; Masaaki Matsuo; Takahiro Ito; Keisuke Suzuki; Keiichi Kimura; Panart Khajornrungruang
Original assignee: Kyushu Institute of Technology NUC; Mishima Kosan Co Ltd
Current assignee: Kyushu Institute of Technology NUC; Mishima Kosan Co Ltd
Priority date: 2012-06-29
Filing date: 2013-06-19
Publication date: 2014-01-02
Also published as: CN103522165B; KR20140002512A; CN103522165A; TWI538777B; TW201417953A

Abstract

A method of manufacturing a polishing pad mold for a polishing pad including a micro pattern α having micro protrusions arranged therein includes steps of manufacturing a mother mold where a mother mold including a substrate, on one side of which a micro pattern β having an inverted protrusion-depression shape with respect to the micro pattern α is formed, is manufactured, manufacturing a positive daughter mold where a positive daughter mold having a micro pattern γ formed on a surface is manufactured by the mold, and manufacturing a negative daughter mold where a negative daughter mold having a micro pattern δ formed on a surface is manufactured by the mold, and an assembly step where the mold is configured by arranging and fixing the molds on a basis with the surfaces having the micro pattern δ faced up. Thereby, highly precise and efficient planarization is provided.

Description

TECHNICAL FIELD

The present invention relates to a method of manufacturing a polishing pad mold, the polishing pad mold manufactured by the method, and a polishing pad manufactured by the polishing pad mold. The polishing pad precisely and efficiently planarizes a semiconductor substrate, etc. for which high flatness is required.

BACKGROUND ART

Conventionally, a polishing pad for a semiconductor substrate is manufactured, for example, by pouring and curing a foamed urethane resin in a frame to form a foamed urethane block, and then by cutting a flat plate having a predetermined thickness (e.g., 1 mm) out of the block. Consequently, the manufactured polishing pad does not have high flatness. Thus, dressing (also known as conditioning) by using a diamond wheel, etc. is performed to provide the polishing pad with high flatness before the polishing pad is used for polishing. However, a surface state of the polishing pad after dressing is unstable and changeable, and a surface state of the polishing pad after a process is significantly different from a surface state of the polishing pad after a previous process. Also, a micro indented pattern formed on a surface of the polishing pad by dressing affects a function of maintaining slurry including a polishing agent on the surface of the polishing pad and a function of feeding the fresh slurry on a polished surface of the semiconductor substrate. However, in a method by dressing, it is impossible to constantly form the micro indented pattern on the surface of the polishing pad, thus the semiconductor substrate cannot be stably planarized with high precision.
In addition, since the polishing pad is made of foamed urethane, pores appear on a superficial layer of the polishing pad, and the polishing agent, scrapings, etc. accumulate in the pores during polishing. Thus, performance of removing the scrapings derived from the semiconductor substrate is gradually degraded, performance of feeding the fresh slurry on the polished surface of the semiconductor substrate is degraded, and a polishing rate is decreased. The surface of the polishing pad is therefore ground periodically to be renewed. However, sizes of cavities in the foamed urethane block are different from each other, and the cavities are unevenly dispersed. Accordingly, size distribution and dispersion condition of the pores appearing on the surface change every time the surface of the polishing pad is ground to be renewed, and it is therefore impossible to always keep polishing performance of the polishing pad constant.
Thus, for example, Patent Literature 1 discloses a technique to manufacture a polishing pad by forming a base body of the polishing pad by an unfoamed member made of a material having high affinity for slurry and by forming a micro indented pattern on a surface of the base body by photolithography. Since the polishing pad is formed by the unfoamed member, a polishing agent, scrapings, etc. do not accumulate on a superficial layer of the polishing pad during polishing. Also, since the micro indented pattern on the surface of the polishing pad is formed by photolithography, the micro indented pattern can always be made constantly. Thus, the slurry can be retained stably on the surface of the polishing pad and the fresh slurry can be supplied stably on a polished surface of a semiconductor substrate.

CITATION LIST

Patent Literature

[Patent Literature 1] Japanese Patent No. 4845347

SUMMARY OF INVENTION

Technical Problem

However, the polishing pad disclosed in Patent Literature 1 is manufactured by forming the micro indented pattern by photolithography on the superficial layer of each of the polishing pad, and thus productivity for the polishing pad significantly deteriorates. Additionally, a manufacturing step of the polishing pad includes a process of manufacturing a body of the polishing pad and a process of forming the micro indented pattern on a surface of the body, thus the manufacturing step becomes complex and time-consuming, and manufacturing cost increases.
Therefore, it can be taken into consideration that a micro indented pattern is formed by MEMS (microelectromechanical system) technology on a surface of a monocrystalline silicon wafer to be used as the semiconductor substrate, and the silicon wafer is used as a mold to manufacture the polishing pad. Here, the micro indented pattern includes, for example, inverted-pyramidal holes (e.g., regular quadrangular pyramid having a square 7 μm on a side, and a depth of 4.9 μm) arranged at a regular interval (e.g., 5 μm). Namely, a resin plate (e.g., urethane resin plate) is pressed onto the silicon wafer having the arranged inverted-pyramidal holes and is heated while being pressed to soften a part of a material of a superficial layer of the resin plate and insert the part of the material into the inverted-pyramidal holes, and the micro indented pattern having pyramidal protruding portions arranged at the regular interval can therefore be formed in the superficial layer of the resin plate. However, since a size of the usable monocrystalline silicon wafer is limited by a size of a monocrystalline silicon rod supplied for manufacturing the semiconductor substrate, the micro indented pattern cannot be formed on the resin plate having a size required as the polishing pad. Also, since the silicon wafer is hard and brittle, it lacks durability for repetitive use.
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method of manufacturing a polishing pad mold, the polishing pad mold manufactured by the method, and a polishing pad manufactured by the polishing pad mold. By the method, the polishing pad which precisely and efficiently planarizes a semiconductor substrate, etc. for which high flatness is required can be manufactured easily and inexpensively.

Solution to Problem

To accomplish the above object, a first aspect of the present invention provides a method of manufacturing a polishing pad mold, the polishing pad mold for manufacturing a polishing pad for planarizing a plate-like polished material (i.e., a plate-like material to be polished), one surface of the polishing pad including a micro pattern α having micro protrusions P distributed and disposed at a predetermined interval, the method comprising: (a) a mother mold manufacturing step, including: providing a resist mask on one surface of a monocrystalline substrate, the resist mask including holes having the same sizes as sizes of bases of the micro protrusions P, the holes formed in accordance with locations of the micro protrusions P in the micro pattern α; and etching the one surface of the substrate via the resist mask to form a micro pattern β on the one surface of the substrate, the micro pattern β having micro depressions Q having inverted protrusion-depression shapes with respect to the micro protrusions P, the micro depressions Q distributed and disposed in accordance with the locations of the micro protrusions P in the micro pattern α, whereby the mother mold including the micro pattern β is manufactured; (b) a positive daughter mold manufacturing step, including: transferring the micro pattern β of the mother mold to form a micro pattern γ including micro protrusions R, the micro protrusions R having the same sizes as the micro depressions Q and having inverted protrusion-depression shapes with respect to the micro depressions Q, the micro protrusions R distributed and disposed at locations corresponding to the micro depressions Q, whereby the positive daughter mold including the micro pattern γ is manufactured; (c) a negative daughter mold manufacturing step, including: transferring the micro pattern γ of the positive daughter mold to form a micro pattern δ including micro depressions S, the micro depressions S having the same sizes as the micro protrusions R and having inverted protrusion-depression shapes with respect to the micro protrusions R, the micro depressions S distributed and disposed at locations corresponding to the micro protrusions R, whereby the negative daughter mold including the micro pattern δ is manufactured; and (d) an assembly step, including: arranging and fixing the negative daughter molds on a basis while surfaces of the negative daughter molds having the micro pattern δ being faced outward and while lateral sides of the negative daughter molds being contacted with each other, whereby the polishing pad mold is configured.
In the method according to the first aspect of the present invention, it is possible that the negative daughter mold comprises a metal plate formed by plating on a surface having the micro pattern γ of the positive daughter mold as a base surface, and the basis with the negative daughter mold fixed thereon is a flat plate.
In the method according to the first aspect of the present invention, it is possible that the negative daughter mold comprises an arc-like metal member, the arc-like metal member formed by plating on a surface having the micro pattern γ of the positive daughter mold as a base surface, the positive daughter mold being bent in an arc in a way that the surface having the micro pattern γ is radially inward, and the basis with the negative daughter mold fixed thereon is a roll having the same curvature as a curvature of a radially-inward side of the arc-like metal member.
A second aspect of the present invention provides a polishing pad mold manufactured by the method according to the first aspect of the present invention.
A third aspect of the present invention provides a polishing pad manufactured by using the polishing pad mold according to the second aspect of the present invention.
In the polishing pad according to the third aspect of the present invention, it is preferable that the substrate is a silicon plate cut out from a monocrystalline silicon rod grown in a [100] direction with a (100) plane as a cutting surface, the resist mask is formed on the (100) plane of the silicon plate, the micro protrusion P is a regular quadrangular pyramid micro protrusion, a length of one side of a base of the regular quadrangular pyramid micro protrusion is 0.1 to 30 μm, and an interval between the adjacent regular quadrangular pyramid micro protrusions is 1 to 30 μm.
A fourth aspect of the present invention provides a method of manufacturing a polishing pad mold, the polishing pad mold for manufacturing a polishing pad for planarizing a plate-like polished material, one surface of the polishing pad including a micro pattern A having micro protrusions distributed and disposed at a predetermined interval, the method comprising: (a) a positive mold manufacturing step, including: forming a processed layer on one surface of a substrate by using a material chemically reactive with an energy ray for accelerating reaction, the processed layer having a thickness corresponding to a height of the micro protrusion; forming micro reactive protrusions by a chemical reaction in the processed layer by changing an energy amount of the energy ray for accelerating reaction depending on a position in the processed layer, the micro reactive protrusions having the same sizes as sizes of the micro protrusions, the micro reactive protrusions disposed in accordance with locations of the micro protrusions; and removing chemically non-reactive regions from the processed layer to form a micro pattern B including the micro reactive protrusions distributed and disposed on the one surface of the substrate, whereby the positive mold including the micro pattern B is manufactured; (b) a negative mold manufacturing step, including: transferring the micro pattern B of the positive mold to form a micro pattern C including micro depressions, the micro depressions having the same sizes as the sizes of the micro reactive protrusions and having inverted protrusion-depression shapes with respect to the micro reactive protrusions, the micro depressions distributed and disposed at locations corresponding to the micro reactive protrusions, whereby the negative mold including the micro pattern C is manufactured; and (c) an assembly step, including: arranging and fixing the negative molds on a basis while surfaces of the negative molds having the micro pattern C being faced outward and while lateral sides of the negative molds being contacted with each other, whereby the polishing pad mold is configured.
In the method according to the fourth aspect of the present invention, it is possible that the substrate is a flat plate, the negative mold comprises a metal plate formed by plating on a surface having the micro pattern B of the positive mold as a base surface, and the basis with the negative mold fixed thereon is a flat plate.
In the method according to the fourth aspect of the present invention, it is possible that the substrate is a flexible flat plate, the negative mold comprises an arc-like metal member, the arc-like metal member formed by plating on a surface having the micro pattern B of the positive mold as a base surface, the positive mold being bent in an arc in a way that the surface having the micro pattern B is radially inward, and the basis with the negative mold fixed thereon is a roll having the same curvature as a curvature of a radially-inward side of the arc-like metal member.
A fifth aspect of the present invention provides a polishing pad mold manufactured by the method according to the fourth aspect of the present invention.
A sixth aspect of the present invention provides a polishing pad manufactured by using the polishing pad mold according to the fifth aspect of the present invention.
In the polishing pad according to the sixth aspect of the present invention, it is preferable that a shape of the micro protrusion is a regular quadrangular pyramid, a length of one side of a base of the regular quadrangular pyramid is 0.1 to 30 μm, and an interval between the adjacent regular quadrangular pyramids is 1 to 30 μm.

Advantageous Effects of Invention

In the method according to the first aspect, since the micro depressions Q are formed by etching via the resist mask including the holes having the same sizes as the bases of the micro protrusions P in accordance with the locations of the micro protrusions P, the micro pattern β having the precisely inverted protrusion-depression shape with respect to the micro pattern α can be formed in the mother mold. In the positive daughter mold manufactured by transferring the micro pattern β of the mother mold, the micro pattern γ (the same pattern as the micro pattern α) is formed. In the negative daughter mold manufactured by transferring the micro pattern γ of the positive daughter mold, the micro pattern δ (the same pattern as the micro pattern β) having the precisely inverted protrusion-depression shape with respect to the micro pattern γ is formed. Thus, by arranging and fixing a plurality of the negative daughter molds manufactured from the mother mold via the positive daughter molds on the basis having a desired area, the precise micro pattern δ (the micro pattern β) is formed all over the desired area. As a result, the polishing pad mold for molding the polishing pad having the desired area can be manufactured readily and inexpensively.
In the method according to the first aspect, when the negative daughter mold includes the metal plate formed by plating on the surface having the micro pattern γ of the positive daughter mold as the base surface, the durable negative daughter mold provided with the precise micro pattern δ can be manufactured efficiently and inexpensively. Also, when the basis on which the negative daughter mold is fixed is the flat plate, the polishing pad mold which enables manufacture of a large-size polishing pad can be manufactured readily and inexpensively.
In the method according to the first aspect, when the negative daughter mold includes the arc-like metal member formed by plating on the surface having the micro pattern γ of the positive daughter mold as the base surface, where the positive daughter mold is bent in the arc in the way that the surface having the micro pattern γ is radially inward, the durable negative daughter mold provided with the precise micro pattern δ can be manufactured efficiently and inexpensively. Also, when the basis on which the negative daughter mold is fixed is the roll having the same curvature as the curvature of the radially-inward side of the arc-like metal member, the polishing pad mold which enables manufacture of the long-length (strip-like) polishing pad having a desired width can be manufactured readily and inexpensively.
In the polishing pad mold according to the second aspect, the micro pattern α having the micro protrusions P distributed and disposed at the predetermined interval can be formed readily and efficiently on one surface of a material for the polishing pad having a desired size. Thus, the polishing pad having the desired size which enables highly precise and highly efficient planarization can be manufactured inexpensively.
In the polishing pad according to the third aspect, the polishing pad includes the precise micro pattern α. Thus, when the polished material is polished by pressing the polishing pad onto the polished material, the polishing pad contacts with the polished surface of the polished material via the tops of the micro protrusions P formed on the polishing pad. Accordingly, the slurry including the polishing agent existing in the gaps between the protrusions P can be efficiently contacted with the polished surface of the polished material. Further, by feeding the slurry continuously during polishing, the fed slurry passes through the gaps between the protrusions P, thereby the fresh slurry can always be contacted with the polished surface of the polished material, and the scrapings generated during polishing can be mixed into the flow of the slurry and removed. As a result, the polished material can be planarized with high precision and high efficiency.
In the polishing pad according to the third aspect, when the substrate is the silicon plate cut out from the monocrystalline silicon rod grown in the direction with the (100) plane as the cutting surface; the resist mask is formed on the (100) plane of the silicon plate; the micro protrusion P is the regular quadrangular pyramid micro protrusion; the length of the one side of the base of the regular quadrangular pyramid micro protrusion is 0.1 to 30 μm; and the interval between the adjacent regular quadrangular pyramid micro protrusions is 1 to 30 μm, the slurry existing in the gaps surrounded by the adjacent regular quadrangular pyramid micro protrusions can be moved along slopes of the regular quadrangular pyramid micro protrusions, thereby the fresh slurry can be efficiently contacted with the polished surface of the polished material. As a result, the whole polished surface can be uniformly polished.
In the method according to the fourth aspect, to manufacture the polishing pad mold for manufacturing the polishing pad in which the micro pattern A including the arranged micro protrusions is formed, the processed layer is formed on the one surface of the substrate by using the material chemically reactive with the energy ray for accelerating reaction, and the micro reactive protrusions are formed by the chemical reaction in the processed layer by changing the energy amount of the energy ray for accelerating reaction depending on the position in the processed layer, where the micro reactive protrusions have the same sizes as the micro protrusions and are disposed in accordance with the locations of the micro protrusions, thereby the positive mold is manufactured. Thus, the micro pattern A of the polishing pad to be manufactured can be reproduced efficiently and accurately as the micro pattern B in the positive mold. Additionally, in the negative mold manufactured by using the positive mold, the micro pattern C is formed which can form the micro pattern A by transferring. Thus, by arranging and fixing the negative molds on the basis having a desired area, the polishing pad mold for molding the polishing pad having the desired area can be manufactured readily and inexpensively.
In the method according to the fourth aspect, when the substrate is the flat plate, and the negative mold includes the metal plate formed by plating on the surface having the micro pattern B of the positive mold as the base surface, the durable negative mold can be manufactured readily and inexpensively. Also, when the basis on which the negative mold is fixed is the flat plate, the polishing pad mold which enables manufacture of a large-size polishing pad can be manufactured readily and inexpensively.
In the method according to the fourth aspect, when the substrate is the flexible flat plate, and the negative mold includes the arc-like metal member formed by plating on the surface having the micro pattern B of the positive mold as the base surface where the positive mold is bent in the arc in the way that the surface having the micro pattern B is radially inward, the durable negative mold can be manufactured readily and inexpensively. Also, when the basis on which the negative mold is fixed is the roll having the same curvature as the curvature of the radially-inward side of the arc-like metal member, the polishing pad mold which enables manufacture of the long-length (strip-like) polishing pad having a desired width can be manufactured readily and inexpensively.
In the polishing pad mold according to the fifth aspect, the micro pattern A having the micro protrusions distributed and disposed at the predetermined interval can be formed readily and efficiently on one surface of a material for the polishing pad having a desired size. Thus, the polishing pad having the desired size which enables highly precise and highly efficient planarization can be manufactured inexpensively.
In the polishing pad according to the sixth aspect, the micro pattern A including the micro protrusions distributed and disposed at the predetermined interval is formed on the one surface of the polishing pad. Thus, when the polished material is polished by using the one surface of the polishing pad, the polishing pad contacts with the polished surface of the polished material via the tops of the micro protrusions formed on the polishing pad. Accordingly, the slurry including the polishing agent existing in the gaps between the protrusions can be efficiently contacted with the polished surface of the polished material. Further, by feeding the slurry continuously during polishing, the fed slurry passes through the gaps between the protrusions, thereby the fresh slurry can always be contacted with the polished surface of the polished material, and the scrapings generated during polishing can be mixed into the flow of the slurry and removed. As a result, the polished material can be planarized with high precision and high efficiency.
In the polishing pad according to the sixth aspect, when the shape of the micro protrusion is the regular quadrangular pyramid, the length of the one side of the base of the regular quadrangular pyramid is 0.1 to 30 μm, and the interval between the adjacent regular quadrangular pyramids is 1 to 30 μm, the slurry existing in the gaps surrounded by the adjacent regular quadrangular pyramids can be moved along slopes of the regular quadrangular pyramids, thereby the fresh slurry can be efficiently contacted with the polished surface of the polished material.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram illustrating a polishing pad mold and a polishing pad manufactured by the polishing pad mold according to a first embodiment of the present invention.

FIG. 2(A) is a plan view illustrating the polishing pad, and FIG. 2(B) is a perspective view illustrating a micro protrusion formed in the polishing pad.

FIG. 3 is an explanatory diagram illustrating a condition of polishing by the polishing pad.

FIGS. 4(A) and 4(B) are explanatory diagrams illustrating a mother mold manufacturing step in the method.

FIGS. 5(A) to 5(C) are explanatory diagrams illustrating a positive daughter mold manufacturing step, a negative daughter mold manufacturing step, and an assembly step in the method, respectively.

FIG. 6 is an explanatory diagram illustrating a polishing pad mold and a polishing pad manufactured by the polishing pad mold according to a second embodiment of the present invention.

FIGS. 7(A) and 7(B) are explanatory diagrams illustrating a mother mold manufacturing step in the method.

FIGS. 8(A) to 8(C) are explanatory diagrams illustrating a positive daughter mold manufacturing step, a negative daughter mold manufacturing step, and an assembly step in the method, respectively.

FIG. 9 is an explanatory diagram illustrating a polishing pad mold and a polishing pad manufactured by the polishing pad mold according a third embodiment of the present invention.

FIG. 10(A) is a plan view illustrating the polishing pad, and FIG. 10(B) is a perspective view illustrating a micro protrusion formed in the polishing pad.

FIG. 11 is an explanatory view illustrating a condition of polishing by the polishing pad.

FIGS. 12(A) to 12(C) are explanatory diagrams illustrating a positive mold manufacturing step in the method.

FIGS. 13(A) to 13(C) are explanatory diagrams illustrating a negative mold manufacturing step in the method.

FIG. 14 is an explanatory diagram illustrating a polishing pad mold and a polishing pad manufactured by the polishing pad mold according to a fourth embodiment of the present invention.

FIGS. 15(A) to 15(C) are explanatory diagrams illustrating a negative mold manufacturing step in the method.

DESCRIPTION OF EMBODIMENTS

Referring to the accompanying drawings, embodiments of the present invention will be described for a better understanding of the invention.
As shown in FIGS. 1 to 3, a polishing pad mold 10 according to a first embodiment of the present invention is used for manufacturing a polishing pad 13. The polishing pad 13 having a micro pattern α is used for planarizing a semiconductor substrate 11 (e.g., silicon wafer), an example of a plate-like polished material. The micro pattern α is formed on one of surfaces (i.e., surface in contact with a processed surface of the semiconductor substrate 11 during planarization) of the polishing pad 13 by arranging, for example, regular quadrangular pyramid micro protrusions 12, which are examples of micro protrusions P, each of the protrusions 12 having a height H to a top of 0.1 to 20 μm (slope angle θ=30 to 80 degrees) and a length L of one side of a base of 0.1 to 30 μm. Here, the regular quadrangular pyramid micro protrusions 12 are arranged and disposed (distributed) at intervals D of 1.1 to 60 μm between the tops of the adjacent protrusions 12 and at intervals G of 1 to 30 μm between the bases of the adjacent protrusions 12. Hereinafter, details will be described.
The polishing pad mold 10 includes an upper mold 14 and a lower mold 15 holding and pressing a deformable flat plate in a vertical direction. Here, the deformable flat plate (e.g., heated and softened plate of polyether ether ketone (PEEK), an example of thermoplastic resin) is a material for the polishing pad 13, and the micro pattern α is formed on one side of the flat plate, for example, an upper surface of the flat plate by the upper mold 14 while the flat plate is being placed on and supported by the lower mold 15. The upper mold 14 includes a pattern molding portion 16 pressing the upper surface of the flat plate to form the micro pattern α on the upper surface by deformation processing, and an upper mold body 17 retaining the pattern molding portion 16. Further, the pattern molding portion 16 includes a plurality of negative daughter molds 18 disposed (fixed) on the upper mold body 17 with lateral sides of the negative daughter molds 18 closely contacting each other, and the negative daughter molds 18 press the flat plate in an integrated fashion to form the micro pattern α.
In each of the negative daughter molds 18, a micro pattern δ (pattern having an inverted protrusion-depression shape with respect to the micro pattern α) including regular quadrangular pyramid micro depressions 19, examples of micro depressions S, is formed. Here, the regular quadrangular pyramid micro depressions 19 having inverted protrusion-depression shapes with respect to the regular quadrangular pyramid micro protrusions 12, where each of the depressions 19 having a depth K to a bottom of 0.1 to 20 μm, are arranged and disposed at intervals E of 1.1 to 60 μm between the bottoms of the adjacent regular quadrangular pyramid micro depressions 19. Also, a length M of one side of an opening 20 of the regular quadrangular pyramid micro depression 19 arranged on a surface of the negative daughter mold 18 (the pattern molding portion 16), a lower surface of the upper mold 14, is 0.1 to 30 μm, and an interval J between the openings 20 is 1 to 30 μm.
In the above-described configuration, by pressing the upper mold 14 from above onto the softened flat plate placed on the lower mold 15, a part of material composing the flat plate enters the regular quadrangular pyramid micro depressions 19 via the openings 20 of the depressions 19 forming the micro pattern δ. After the depressions 19 are filled with the part of the material composing the flat plate, by moving the upper mold 14 above to detach the upper mold 14 from the flat plate, the regular quadrangular pyramid micro protrusions 12 formed by the material entered the regular quadrangular pyramid micro depressions 19 are arranged and disposed on the upper surface of the flat plate, and thereby the micro pattern α is formed. Thereafter, by cooling and curing the flat plate having the micro pattern α, the polishing pad 13 is made.
Further, when the upper mold 14 is pressed onto the flat plate, by maintaining a constant distance between an upper surface of the lower mold 15 and a lower surface of the upper mold 14, a distance between the top of each of the regular quadrangular pyramid micro protrusions 12 and a lower surface of the polishing pad 13 can be constant (a thickness of the polishing pad 13 can be uniform). Thereby, when the semiconductor substrate 11 and the polishing pad 13 are in contact with each other, a contacting surface of the semiconductor substrate 11 with the polishing pad 13 can be parallel to the lower surface of the polishing pad 13.
Hereafter, a method of manufacturing the polishing pad mold 10 according to the first embodiment of the present invention will be described.
As shown in FIGS. 4(A) and 4(B), the method of manufacturing the polishing pad mold 10 includes a mother mold manufacturing step. In the mother mold manufacturing step, a monocrystalline substrate, for example, a silicon plate 21 is cut out from a monocrystalline silicon rod grown in a [100] direction with a (100) plane as a cutting surface. Thereafter, on one side of the silicon plate 21, a resist mask 23 having a square hole 22 of the same size as the base of the regular quadrangular pyramid micro protrusion 12 in a region corresponding to the base of the protrusion 12 is provided, and via the resist mask 23, etching is performed using a difference in a removal rate defined by each crystal plane of the silicon plate 21. Thereby, a mother mold 26 provided with a micro pattern β having the inverted protrusion-depression shape with respect to the micro pattern α is manufactured. Here, the micro pattern β includes regular quadrangular pyramid micro depressions 24 (slope angle φ=30 to 80 degrees), which are examples of micro depressions Q, having the inverted protrusion-depression shapes with respect to the regular quadrangular pyramid micro protrusions 12 and formed by etch pits having depths to bottoms of 0.1 to 20 μm. The depressions 24 are arranged at intervals E of 1.1 to 60 μm between the bottoms of the adjacent depressions 24, with a length M of a side of an opening 25 of the depression 24 of 0.1 to 30 μm, and at intervals J of 1 to 30 μm between the openings 25. In the micro pattern β, the depressions 24 are distributed and disposed corresponding to locations of the regular quadrangular pyramid micro protrusions 12 on the micro pattern α.
As shown in FIGS. 5(A) to 5(C), the method of manufacturing the polishing pad mold 10 also includes a positive daughter mold manufacturing step. In the positive daughter mold manufacturing step, by using the mother mold 26, the micro pattern β is transferred (with an inverted protrusion-depression shape with respect to the micro pattern β) and formed as a micro pattern γ onto a surface of a plate-like resin material. Here, the micro pattern γ includes regular quadrangular pyramid micro protrusions 29, examples of micro protrusions R, distributed and disposed. Thus, a positive daughter mold 27 made of the plate-like resin material is manufactured. Further, the method of manufacturing the polishing pad mold 10 includes a negative daughter mold manufacturing step. In the negative daughter mold manufacturing step, a plated metal 31 (e.g., nickel, cobalt, cobalt-nickel alloy, cobalt-phosphorus alloy), an example of a plate-like metal material, is formed by plating on a surface of the positive daughter mold 27 having the micro pattern γ. On a surface of the plated metal 31, a micro pattern δ having an inverted protrusion-depression shape with respect to the micro pattern γ and including the regular quadrangular pyramid micro depressions 19 is formed. Thereby, a negative daughter mold 18 provided with the plated metal 31 is manufactured. Moreover, the method of manufacturing the polishing pad 10 includes an assembly step. In the assembly step, while surfaces of the negative daughter molds 18 having the micro pattern δ are faced up and lateral sides of the molds 18 are contacted with each other, the molds 18 are arranged and fixed on the upper mold body 17 made of the flat plate (e.g., stainless-steel plate, plain steel plate, alloy steel plate, cast iron plate, and non-ferrous metal plate such as aluminum), an example of a basis. Thereby, the upper mold 14 of the polishing pad mold 10 is configured. Details will be described hereinafter.
(1) Mother Mold Manufacturing Step
As shown in FIG. 4(A), the resist mask 23 is formed by forming a resist layer (e.g., acrylic resin, epoxy resin) and forming the holes 22 by lithography on one (100) plane of the cut-out silicon plate 21. Here, the resist layer is also formed on each of the other (100) planes and a lateral side of the silicon plate 21. Thereafter, etchant is contacted with the one (100) plane of the silicon plate 21 via the resist mask 23. As the etchant, potassium hydroxide, tetramethylammonium hydroxide, etc. is used. The etchant contacts an exposed area of the silicon plate 21 exposed from the hole 22 of the resist mask 23, the exposed area is then etched as silicon hydroxide formed by reaction with the etchant is dissolved in the etchant, and thus the etch pit is formed.
Here, the (100) plane of the silicon plate 21 is etched at a rate limited by an etching rate of a (111) plane, because the etching rate of the (111) plane where silicon atoms are close-packed is the lowest. Thus, the etch pit is formed with a regular quadrangular pyramidal shape having a length of a side of the bottom identical to a length of a side of the square hole 22 and a slope formed by the (111) plane. After etching is performed for a predetermined period of time, the etchant is removed from the silicon plate 21, and the silicon plate 21 is cleaned. Thereby, the micro pattern β including the regular quadrangular pyramid micro depressions 24 having the inverted protrusion-depression shapes with respect to the regular quadrangular pyramid micro protrusions 12 can be formed on the one (100) plane of the silicon plate 21. Thereafter, the resist mask 23 is dissolved in a chemical (e.g., TMAH (tetramethylammonium hydroxide solution), KOH (potassium hydroxide solution), EDP (ethylenediamine pyrocatechol solution)) and removed. Thus, the mother mold 26 is obtained as shown in FIG. 4(B).
(2) Positive Daughter Mold Manufacturing Step
As shown in FIG. 5(A), when the positive daughter mold 27 is manufactured from the plate-like resin material by using the mother mold 26, in a case where a thermoplastic resin (e.g., silicone, fluorine resin, PEEK (polyether ether ketone)) is used as the resin material, the plate-like resin material heated to a softening temperature is placed on an unillustrated molding board, and then the mother mold 26 is pressed on from above. In a case where a thermosetting resin (e.g., epoxy resin, urethane resin, polyester resin) is used as the resin material, the resin material without being heated is poured onto the unillustrated molding board, and then the mother mold 26 is pressed on from above. Thereby, a part of the plate-like resin material enters the regular quadrangular pyramid micro depressions 24 via the openings 25 of the depressions 24. After the depressions 24 are filled with the part of the resin material, by moving the mother mold 26 above to detach the mother mold 26 from the resin material, regular quadrangular pyramid micro protrusions 29 formed by the resin material entered the regular quadrangular pyramid micro depressions 24 are arranged and disposed (distributed) on an upper surface of the resin material. Here, the regular quadrangular pyramid micro protrusions 29 have inverted protrusion-depression shapes with respect to the regular quadrangular pyramid micro depressions 24, i.e., have the same shapes as the regular quadrangular pyramid micro protrusions 12. Thus, the positive daughter mold 27 provided with the micro pattern γ is formed.
Further, in a case where a curable resin (e.g., silicone, fluorine resin) or a photocurable resin (e.g., acrylic resin curable by ultraviolet irradiation) is used as the resin material, an unillustrated casting mold is configured by using the mother mold 26, the resin material is injected into the casting mold, and a part of the resin material enters the regular quadrangular pyramid micro protrusions 24 via the openings 25 of the depressions 24. After the resin material is cured and removed from the casting mold, the regular quadrangular pyramid micro protrusions 29 formed by the resin material entered the regular quadrangular pyramid micro depressions 24 are arranged and disposed on an upper surface of the resin material. Thereby, the positive daughter mold 27 provided with the micro pattern γ is formed.
(3) Negative Daughter Mold Manufacturing Step
As shown in FIG. 5(B), to manufacture the negative daughter mold 18 from the positive daughter mold 27, an electrode layer 30 made of a metal is firstly formed by PVD (e.g., vapor deposition) on a surface having the micro pattern γ of the positive daughter mold 27. Here, the metal composing the electrode layer 30 must have good adhesion to the plated metal 31 composing the negative daughter mold 18, and for example, nickel, gold, silver, or copper can be used. Next, on the electrode layer 30 (with a surface of the electrode layer 30 as a base surface), the plated metal 31 having a thickness of, for example, 0.1 to 5 mm is formed by electroplating. Thereby, the negative daughter mold 18 is obtained.
Thereafter, the negative daughter mold 18 is detached from the positive daughter mold 27, and a thickness of the negative daughter mold 18 is adjusted by polishing a surface (opposite to the electrode layer 30) of the plated metal 31. Here, the micro pattern γ of the positive daughter mold 27 is transferred onto the electrode layer 30 formed on the positive daughter mold 27. Thus, on the negative daughter mold 18, the regular quadrangular pyramid micro depressions 19 having the inverted protrusion-depression shapes with respect to the regular quadrangular pyramid micro protrusions 29 (the regular quadrangular pyramid micro protrusions 12) are arranged and disposed. Here, the depression 19 has the depth K to the bottom of 0.1 to 20 μm and the length M of one side of the opening 20, the interval J between the openings 20 is 1 to 30 μm, and the interval E between the bottoms of the adjacent depressions 19 is 1.1 to 60 μm. Namely, on positions corresponding to the regular quadrangular pyramid micro protrusions 29, the regular quadrangular pyramid micro depressions 19 having the same sizes as the protrusions 29 are distributed and disposed. Thus, the micro pattern δ is formed.
(4) Assembly Step
As shown in FIG. 5(C), to configure the upper mold 14 with the negative daughter molds 18, the negative daughter molds 18 are arranged and fixed on a lower surface of the upper mold body 17 while surfaces of the negative daughter molds 18 having the micro pattern δ are faced up and lateral sides of the molds 18 are contacted with each other. Here, to dispose the negative daughter molds 18 closely-contacted with each other on the upper mold body 17, an interval E′ between the bottoms of the adjacent regular quadrangular pyramid micro depressions 19 over a border between the adjacent molds 18 must be adjusted to the same value as the interval E between the bottoms of the adjacent depressions 19 inside the mold 18. Thereby, continuity of the micro pattern δ is ensured between the adjacent negative daughter molds 18.
Hereinafter, a function of the polishing pad 13 manufactured by using the polishing pad mold 10 will be described.
Since the polishing pad 13 is manufactured by holding and pressing the deformable flat plate in the vertical direction by using the upper mold 14 and the lower mold 15, the polishing pad 13 is provided with high flatness. Also, as shown in FIGS. 2(A), 2(B), and 3, the micro pattern α is formed on the one side of the polishing pad 13. Here, the micro pattern α includes the regular quadrangular pyramid micro protrusions 12 (slope angle θ=30 to 80 degrees) having the heights H to the tops of 0.1 to 20 μm, and the lengths L of the one sides of the bases of 0.1 to 30 μm. The protrusions 12 are arranged and disposed on the micro pattern α at the interval D of 1.1 to 60 μm between the tops of the adjacent protrusions 12, and at the interval G of 1 to 30 μm between the adjacent protrusions 12. Accordingly, a series of operations including cutting a flat plate used as a base material for a polishing pad out of a material for the polishing pad and performing dressing (ensuring flatness of the polishing pad and forming a micro indented pattern) which requires a good skill are no longer necessary. As a result, planarization of the semiconductor substrate 11 can be performed promptly, and polishing performance of the polishing pad 13 can always be maintained constant.
When planalizing the semiconductor substrate 11, the semiconductor substrate 11 is supported by the tops of the regular quadrangular pyramid micro protrusions 12 composing the micro pattern α of the polishing pad 13, and slurry (including a polishing agent) added dropwise from above to a center of the polishing pad 13 exists in gaps between the protrusions 12. Thus, the slurry can always be contacted with a lower surface (polished surface) of the semiconductor substrate 11. Also, since the gaps between the protrusions 12 are continuous, by feeding the fresh slurry to the polishing pad 13, scrapings produced during polishing is moved with the used slurry to a circumference of the polishing pad 13, and then can be discharged from the polishing pad 13. Here, since no pore exists in the material forming the polishing pad 13, the scrapings do not enter into the polishing pad 13. As a result, feeding of the fresh slurry to and removal of the scrapings from the polished surface of the semiconductor substrate 11 can be efficiently performed. Thus, the semiconductor substrate 11 can be stably planarized with high precision while a high polishing rate is maintained.
As shown in FIG. 6, a polishing pad mold 32 according to a second embodiment of the present invention is used to manufacture a polishing pad strip 34. The polishing pad strip 34 having a micro pattern α is used to planarize a semiconductor substrate 11 (see FIG. 3), an example of a plate-like polished material. The micro pattern α is formed on one side (i.e., side in contact with a processed surface of the semiconductor substrate 11) of the polishing pad strip 34 by arranging regular quadrangular pyramid micro protrusions 33, which are examples of a micro protrusions P, having a height H to a top of 0.1 to 20 μm (slope angle θ=30 to 80 degrees) and a length L of one side of a base of 0.1 to 30 μm. Here, the regular quadrangular pyramid micro protrusions 33 are arranged and disposed at intervals D of 1.1 to 60 μm between the tops of the adjacent protrusions 33 and at intervals G of 1 to 30 μm between the bases of the adjacent protrusions 33. Hereinafter, details will be described.
The polishing pad mold 32 includes a pair of an upper roll 36 and a lower roll 37 holding and pressing a deformable strip-like plate 35 in a vertical direction. Here, the strip-like plate 35 (e.g., heated and softened strip-like plate of polyether ether ketone (PEEK), an example of thermoplastic resin) is a material for the polishing pad strip 34, and the micro pattern α is formed on one side of the strip-like plate 35, for example, an upper surface of the strip-like plate 35 by the upper roll 36 and the lower roll 37. Here, a gap corresponding to a thickness of the polishing pad strip 34 is provided between the upper roll 36 and the lower roll 37, and the upper roll 36 and the lower roll 37 revolve in opposite directions during pressing. The upper roll 36 includes a pattern molding portion 38 pressing the upper surface of the strip-like plate 35 to form the micro pattern α on the upper surface by deformation processing, and a roll body 39 retaining the pattern molding portion 38. Further, the pattern molding portion 38 includes a plurality of negative daughter molds 40 disposed (fixed) on a periphery of the roll body 39 with lateral sides of the negative daughter molds 40 closely contacting each other, and the negative daughter molds 40 press the strip-like plate 35 in an integrated fashion to form the micro pattern α.
In each of the negative daughter molds 40, a micro pattern δ (pattern having an inverted protrusion-depression shape with respect to the micro pattern α) including regular quadrangular pyramid micro depressions 41, examples of micro depressions S, is formed. Here, the regular quadrangular pyramid micro depressions 41 having inverted protrusion-depression shapes with respect to the regular quadrangular pyramid micro protrusions 33 and having a depth K to a bottom of 0.1 to 20 μm are arranged and disposed at intervals E of 1.1 to 60 μm between the bottoms of the adjacent regular quadrangular pyramid micro depressions 41. Also, a length M of one side of an opening 42 of the regular quadrangular pyramid micro depression 41 arranged on a surface of the negative daughter mold 40 (the pattern molding portion 38), the periphery of the upper roll 36, is 0.1 to 30 μm, and an interval J between the openings 42 is 1 to 30 μm.
In the above-described configuration, by pressing the upper roll 36 from above onto the softened strip-like plate 35 inserted between the upper roll 36 and the lower roll 37 revolving in opposite directions, a part of material composing the strip-like plate 35 enters the regular quadrangular pyramid micro depressions 41 via the openings 42 of the depressions 41 forming the micro pattern δ. Thus, on the upper surface of the strip-like plate 35 passed between the upper roll 36 and the lower roll 37, the regular quadrangular pyramid micro protrusions 33 formed by the material entered the regular quadrangular pyramid micro depressions 41 are arranged and disposed, and thereby the micro pattern α is formed. After the strip-like plate 35 (the polishing pad strip 34) having the micro pattern α is cooled and cured, the plate 35 is cut into a predetermined size, and thus the polishing pad 34 a is made.
Further, by maintaining a constant gap between the upper roll 36 and the lower roll 37, a distance between the top of each of the regular quadrangular pyramid micro protrusions 33 and a lower surface of the polishing pad strip 34 can be constant (i.e., a thickness of the polishing pad 34 a can be uniform). Thereby, when the semiconductor substrate 11 and the polishing pad 34 a are in contact with each other, a contacting surface of the semiconductor substrate 11 with the polishing pad 34 a can be parallel to the lower surface of the polishing pad 34 a.
Hereafter, a method of manufacturing the polishing pad mold 32 according to the second embodiment of the present invention will be described. As shown in FIGS. 7(A) and 7(B), the method of manufacturing the polishing pad mold 32 includes a mother mold manufacturing step. In the mother mold manufacturing step, a monocrystalline substrate, for example, a silicon plate 43 is cut out from a monocrystalline silicon rod grown in a [100] direction with a (100) plane as a cutting surface. Thereafter, on one side of the silicon plate 43, a resist mask 45 having a square hole 44 of a same size as the base of the regular quadrangular pyramid micro protrusion 33 in a region corresponding to the base of the protrusion 33 is provided, and via the resist mask 45, etching is performed using a difference in a removal rate defined by each crystal plane of the silicon plate 43. Thereby, a mother mold 48 provided with a micro pattern β having an inverted protrusion-depression shape with respect to the micro pattern α is manufactured. Here, the micro pattern β includes regular quadrangular pyramid micro depressions 46 (slope angle φ=30 to 80 degrees), which are examples of micro depressions Q, having inverted protrusion-depression shapes with respect to the regular quadrangular pyramid micro protrusions 33 and formed by etch pits having depths to bottoms of 0.1 to 20 μm. The depressions 46 are arranged at intervals E of 1.1 to 60 μm between the bottoms of the adjacent depressions 46, with a length M of a side of an opening 47 of the depression 46 of 0.1 to 30 μm, and at intervals J of 1 to 30 μm between the openings 47.
As shown in FIGS. 8(A) to 8(C), the method of manufacturing the polishing pad mold 32 also includes a positive daughter mold manufacturing step, a negative daughter mold manufacturing step, and an assembly step. In the positive daughter mold manufacturing step, by using the mother mold 48, a positive daughter mold 49 made of a plate-like resin material is molded and manufactured. Here, the micro pattern β is transferred (with an inverted protrusion-depression shape with respect to the micro pattern β) and formed as a micro pattern γ onto one surface of the plate-like resin material. In the negative daughter mold manufacturing step, the obtained positive daughter mold 49 is bent in a way that the surface having the micro pattern γ is radially inward. By plating, a micro pattern δ having an inverted protrusion-depression shape with respect to the micro pattern γ is formed on the radially inward surface, and a plated metal 53 (e.g., nickel, cobalt, cobalt-nickel alloy, cobalt-phosphorus alloy), an example of a arc-like metal material, including the micro pattern δ on the surface is formed. Thereby, a negative daughter mold 40 including the plated metal 53 is manufactured. In the assembly step, while surfaces of the negative daughter molds 40 having the micro pattern δ are faced up and lateral sides of the molds 40 are contacted with each other, the molds 40 are arranged and fixed on the roll body 39 (e.g., stainless-steel roll, plain steel roll, alloy steel roll, cast iron roll, and non-ferrous metal roll such as aluminum), an example of a basis. Thereby, the upper roll 36 of the polishing pad mold 32 is configured. Details will be described hereinafter.
(1) Mother Mold Manufacturing Step
As shown in FIG. 7(A), the resist mask 45 is formed by forming a resist layer (e.g., acrylic resin, epoxy resin) and forming the holes 44 by lithography on one (100) plane of the cut-out silicon plate 43. Here, the resist layer is also formed on each of the other (100) planes and a lateral side of the silicon plate 43. Thereafter, etchant is contacted with the one (100) plane of the silicon plate 43 via the resist mask 45. As the etchant, potassium hydroxide, tetramethylammonium hydroxide, etc. is used. The etchant contacts an exposed area of the silicon plate 43 exposed from the hole 44 of the resist mask 45, the exposed area is then etched as silicon hydroxide formed by reaction with the etchant is dissolved in the etchant, and thus the etch pit is formed.
Here, the (100) plane of the silicon plate 43 is etched at a rate limited by an etching rate of a (111) plane, because the etching rate of the (111) plane is the lowest. Thus, the etch pit is formed with a regular quadrangular pyramidal shape having a length of a side of the bottom identical to a length of a side of the square hole 44 and a slope formed by the (111) plane. After etching is performed for a predetermined period of time, the etchant is removed from the silicon plate 43, and the silicon plate 43 is cleaned. Thereby, the micro pattern β including the regular quadrangular pyramid micro depressions 46 having the inverted protrusion-depression shapes with respect to the regular quadrangular pyramid micro protrusions 33 forming the micro pattern α can be formed on the one (100) plane of the silicon plate 43. Thereafter, the resist mask 45 is dissolved in an organic solvent (e.g., acetone) and removed. Thus, the mother mold 48 is obtained as shown in FIG. 7(B).
(2) Positive Daughter Mold Manufacturing Step
As shown in FIG. 8(A), when the positive daughter mold 49 is manufactured from the plate-like resin material by using the mother mold 48, in a case where a thermoplastic resin (e.g., silicone, fluorine resin, PEEK (polyether ether ketone)) is used as the resin material, the plate-like resin material heated to a softening temperature is placed on an unillustrated molding board, and then the mother mold 48 is pressed on from above. Thereby, a part of the plate-like resin material enters the regular quadrangular pyramid micro depressions 46 via the openings 47 of the depressions 46. After the depressions 46 are filled with the part of the resin material, by moving the mother mold 48 above to detach the mother mold 48 from the resin material, regular quadrangular pyramid micro protrusions 51 formed by the resin material entered the regular quadrangular pyramid micro depressions 46 are arranged and disposed on an upper surface of the resin material. Here, the regular quadrangular pyramid micro protrusions 51, examples of the micro protrusions R, have inverted protrusion-depression shapes with respect to the regular quadrangular pyramid micro depressions 46 forming the micro pattern β, i.e., have the same shapes as the regular quadrangular pyramid micro protrusions 33. Thus, the positive daughter mold 49 provided with the micro pattern γ is formed.
Further, in a case where a curable resin (e.g., silicone, fluorine resin) or a photocurable resin (e.g., acrylic resin curable by ultraviolet irradiation) is used as the resin material, an unillustrated casting mold is configured by using the mother mold 48, the resin material is injected into the casting mold, and a part of the resin material enters the regular quadrangular pyramid micro protrusions 46 via the openings 47 of the depressions 46. After the resin material is cured and removed from the casting mold, the regular quadrangular pyramid micro protrusions 51 formed by the resin material entered the regular quadrangular pyramid micro depressions 46 forming the micro pattern β are arranged and disposed on an upper surface of the resin material. Thereby, the positive daughter mold 49 provided with the micro pattern γ is formed.
(3) Negative Daughter Mold Manufacturing Step
As shown in FIG. 8(B), to manufacture the negative daughter mold 40 from the positive daughter mold 49, firstly, the positive daughter mold 49 is bent in a way that a surface having the micro pattern γ is radially inward, and then an electrode layer 52 made of a metal is formed by PVD (e.g., vapor deposition) on the surface. Here, the metal composing the electrode layer 52 must have good adhesion to the plated metal 53 composing the negative daughter mold 40, and for example, nickel, gold, silver, or copper can be used. Next, on the electrode layer 52 as a base layer, the plated metal 53 having a thickness of, for example, 0.1 to 5 mm is formed by electroplating. Thereby, the negative daughter mold 40 is obtained.
Thereafter, the negative daughter mold 40 is removed from the positive daughter mold 49, and a thickness of the negative daughter mold 40 is adjusted by polishing a surface (opposite to the electrode layer 52) of the plated metal 53. Here, the micro pattern γ of the positive daughter mold 49 is transferred onto the electrode layer 52 formed on the positive daughter mold 49. Thus, on the negative daughter mold 40, the regular quadrangular pyramid micro depressions 41 having inverted protrusion-depression shapes with respect to the regular quadrangular pyramid micro protrusions 51 (the regular quadrangular pyramid micro protrusions 33) are arranged and disposed. Here, the depression 41 has a depth K to a bottom of 0.1 to 20 μm and a length M of one side of the opening 42, the interval J between the openings 42 is 1 to 30 μm, and the interval E between the bottoms of the adjacent depressions 41 is 1.1 to 60 μm. Thus, the micro pattern δ is formed.
(4) Assembly Step
As shown in FIG. 8(C), to configure the upper roll 36 with the negative daughter molds 40, the negative daughter molds 40 are arranged and fixed on a surface of the roll body 39 while surfaces of the negative daughter molds 40 having the micro pattern δ are faced up and lateral sides of the molds 40 are contacted with each other. Here, a radius of the roll body 39 is adjusted in a way that a curvature of the radius is the same as a curvature of a radially-inward side of the mold 40 (the plated metal 53). To dispose the negative daughter molds 40 closely-contacted with each other on the roll body 39, an interval E′ between the bottoms of the adjacent regular quadrangular pyramid micro depressions 41 over a border between the adjacent molds 40 must be adjusted to the same value as the interval E between the bottoms of the adjacent depressions 41 inside the mold 18. Thereby, continuity of the micro pattern δ is ensured between the adjacent negative daughter molds 40.
Note that descriptions about a function of the polishing pad 34 a manufactured by using the polishing pad mold 32 are omitted because the function of the polishing pad 34 a is the same as the function of the polishing pad 13 manufactured by using the polishing pad mold 10.
As shown in FIGS. 9, 10(A), 10(B), and 11, a polishing pad mold 60 according to a third embodiment of the present invention is used to manufacture a polishing pad 63. The polishing pad 63 having a micro pattern A is used to planarize a semiconductor substrate 61 (e.g., silicon wafer), an example of a plate-like polished material. The micro pattern A is formed on one of surfaces (i.e., surface in contact with a processed surface of a semiconductor substrate 11 during planarization) of the polishing pad 63 by arranging, for example, regular quadrangular pyramid micro protrusions 62, which are examples of micro protrusions having a height H2 to a top of 0.1 to 20 μm (slope angle θ=30 to 80 degrees) and a length L2 of one side of a base of 0.1 to 30 μm. Here, the regular quadrangular pyramid micro protrusions 62 are arranged and disposed (distributed) at intervals D2 of 1.1 to 60 μm between the tops of the adjacent protrusions 62 and at intervals G2 of 1 to 30 μm between the bases of the adjacent protrusions 62. Hereinafter, details will be described.
The polishing pad mold 50 includes an upper mold 64 and a lower mold 65 holding and pressing a deformable flat plate in a vertical direction. Here, the deformable flat plate (e.g., heated and softened plate of polyether ether ketone (PEEK), an example of thermoplastic resin) is a material for the polishing pad 63, and the micro pattern A is formed on one side of the flat plate, for example, an upper surface of the flat plate by the upper mold 64 while the flat plate is being placed on and supported by the lower mold 65. The upper mold 64 includes a pattern molding portion 66 pressing the upper surface of the flat plate to form the micro pattern A on the upper surface by deformation processing, and an upper mold body 67 retaining the pattern molding portion 66. Further, the pattern molding portion 66 includes a plurality of negative molds 68 disposed (fixed) on the upper mold body 67 with lateral sides of the negative molds 68 closely contacting each other, and the negative molds 68 press the flat plate in an integrated fashion to form the micro pattern A.
In each of the negative molds 68, a micro pattern C (pattern having an inverted protrusion-depression shape with respect to the micro pattern A) including regular quadrangular pyramid micro depressions 69, examples of micro depressions, is formed. Here, the regular quadrangular pyramid micro depressions 69 having inverted protrusion-depression shapes with respect to the regular quadrangular pyramid micro protrusions 62 and having a depth K2 to a bottom of 0.1 to 20 μm are arranged and disposed at intervals E2 of 1.1 to 60 μm between the bottoms of the adjacent regular quadrangular pyramid micro depressions 69. Also, a length M2 of one side of an opening 70 of the regular quadrangular pyramid micro depression 69 arranged on a surface of the negative mold 68 (the pattern molding portion 66), a lower surface of the upper mold 64, is 0.1 to 30 μm, and an interval J2 between the openings 70 is 1 to 30 μm.
In the above-described configuration, by pressing the upper mold 64 from above onto the softened flat plate placed on the lower mold 65, a part of material composing the flat plate enters the regular quadrangular pyramid micro depressions 69 via the openings 70 of the depressions 69 forming the micro pattern C. After the depressions 69 are filled with the part of the material composing the flat plate, by moving the upper mold 64 above to detach the upper mold 64 from the flat plate, the regular quadrangular pyramid micro protrusions 62 formed by the material entered the regular quadrangular pyramid micro depressions 69 are arranged and disposed on the upper surface of the flat plate, and thereby the micro pattern A is formed. Thereafter, by cooling and curing the flat plate having the micro pattern A, the polishing pad 63 is made. Further, when the upper mold 64 is pressed onto the flat plate, by maintaining a constant distance between an upper surface of the lower mold 65 and a lower surface of the upper mold 64, a distance between the top of each of the regular quadrangular pyramid micro protrusions 62 and a lower surface of the polishing pad 63 can be constant (a thickness of the polishing pad 63 can be uniform). Also, a flat surface contacting with each of the tops of the protrusions 62 can be parallel to the lower surface of the polishing pad 63.
Hereafter, a method of manufacturing the polishing pad mold 60 according to the third embodiment of the present invention will be described.
As shown in FIGS. 12(A) to 12(C), the method of manufacturing the polishing pad mold 60 includes a positive mold manufacturing step. In the positive mold manufacturing step, a processed layer 72 having a thickness corresponding to the height of the regular quadrangular pyramid micro protrusion 62 is formed on one surface of a silicon plate 71, an example of a substrate, by using a material (e.g., ultraviolet curable resin) chemically reactive with ultraviolet irradiation, an example of an energy ray for accelerating reaction. Next, by changing an energy amount of the ultraviolet irradiation depending on a position in the processed layer 72, regular quadrangular pyramid micro protruding portions 73, examples of micro reactive protrusions, having the same sizes as the regular quadrangular pyramid micro protrusions 62 are formed by a chemical reaction in the processed layer 72 in accordance with locations of the protrusions 62 forming the micro pattern A. Thereafter, by removing chemically non-reactive regions 74 from the processed layer 72, a micro pattern B including the distributed regular quadrangular pyramid micro protruding portions 73 is formed on the one surface of the silicon plate 71. Thus, a positive mold 75 including the silicon plate 71 is manufactured.
Further, as shown in FIGS. 13(A) to 13(C), the method of manufacturing the polishing pad mold 60 includes a negative mold manufacturing step and an assembly step. In the negative mold manufacturing step, by transferring the micro pattern B of the positive mold 75, the micro pattern C is formed. Here, the micro pattern C includes the regular quadrangular pyramid micro depressions 69, examples of micro depressions, having the same sizes as the regular quadrangular pyramid micro protruding portions 73 and having inverted protrusion-depression shapes with respect to the protruding portions 73, distributed and disposed at locations corresponding to the protruding portions 73. Thus, a negative mold 68 including the micro pattern C is manufactured. In the assembly step, while surfaces of the negative molds 68 having the micro pattern C are faced outward and lateral sides of the molds 68 are contacted with each other, the molds 68 are arranged and fixed on the upper mold body 67 made of a flat plate (e.g., stainless-steel plate, plain steel plate, alloy steel plate, cast iron plate, and non-ferrous metal plate such as aluminum), an example of a basis. Thereby, the upper mold 64 of the polishing pad mold 60 is configured. Details will be described hereinafter.
To form the regular quadrangular pyramid micro protruding portions 73 in the processed layer 72 formed on the silicon plate 71 shown in FIG. 12 (A) by changing the energy amount of the ultraviolet irradiation depending on the position in the processed layer 72, an ultraviolet beam 76 generated from an unillustrated ultraviolet light source (e.g., a laser beam generator which generates ultraviolet-range light) is reflected by a digital mirror device (also referred to as digital micromirror device, DMD) 77 shown in FIG. 12(B) and irradiated at an intended position in the processed layer 72. In other words, micro mirrors 78 are arranged and disposed on a plane of the DMD 77, and a reflective surface of each of the micro mirrors 78 can be tilted in a given direction. Thus, by adjusting a tilting angle of the reflective surface of each of the micro mirrors 78, a part of ultraviolet rays composing the ultraviolet beam 76 can be reflected by a plurality of the micro mirrors 78 and can be simultaneously entered into the processed layer 72 with each of a plurality of predetermined positions in the processed layer 72 as a focal point, and the other part of the ultraviolet rays composing the ultraviolet beam 76 can be reflected by the other micro mirrors 78 toward an outside of the processed layer 72. Also, by adjusting an ultraviolet irradiation time (by changing the number of laser shots by the laser beam generator), the energy amount of the ultraviolet irradiation can be changed depending on the predetermined position in the processed layer 72.
Thereby, the regular quadrangular pyramid micro protruding portions 73 can be formed in a short time with a high processing accuracy (e.g., each of locational accuracy and dimensional accuracy is 0.01 to 1 μm) in the processed layer 72 corresponding to the locations of the regular quadrangular pyramid micro protrusions 62 in the micro pattern A. Accordingly, as shown in FIG. 12(B), the processed layer 72 is composed of a plurality of the regular quadrangular pyramid micro protruding portions 73 fixed on the silicon plate 71 and the chemically non-reactive regions 74 existing between the protruding portions 73. Thereafter, the chemically non-reactive regions 74 are dissolved in a chemical (e.g., TMAH (tetramethylammonium hydroxide solution), KOH (potassium hydroxide solution), EDP (ethylenediamine pyrocatechol solution)) and removed. Thus, as shown in FIG. 12(C), the positive mold 75 having the micro pattern B including the protruding portions 73 distributed and disposed on the one surface of the silicon plate 71 is obtained. (Positive mold manufacturing step)
To manufacture the negative mold 68 by using the positive mold 75, firstly, as shown in FIG. 13(A), an electrode layer 79 made of a metal having a thickness of, for example, 0.01 to 1 μm is formed by PVD (e.g., vapor deposition) on a surface having the micro pattern B of the positive mold 75. Next, as shown in FIG. 13(B), on a surface of the electrode layer 79 formed along the surface having the micro pattern B of the positive mold 75 as a base surface, a metal plate 80 having a predetermined thickness of, for example, 0.1 to 5 mm is formed by electroplating. Here, the metal composing the electrode layer 79 must have good adhesion to the metal plate 80 composing the negative mold 68. For example, when an acrylic resin or an epoxy resin, etc. is used as the ultraviolet curable resin, the electrode layer 79 is preferably formed by nickel, gold, silver, or copper, etc., and the metal plate 80 is formed by nickel, cobalt, cobalt-nickel alloy, or nickel-phosphorus alloy, etc.
Thereafter, the negative mold 68 is detached from the positive mold 75, and a thickness of the negative mold 68 is adjusted by polishing a surface (opposite to the electrode layer 79) of the metal plate 80. Here, the micro pattern B of the positive mold 75 is transferred onto the electrode layer 79 formed on the positive mold 75. Thus, on the negative mold 68, the regular quadrangular pyramid micro depressions 69 having inverted protrusion-depression shapes with respect to the regular quadrangular pyramid micro protruding portions 73 (the regular quadrangular pyramid micro protrusions 62) are arranged and disposed. Here, the depression 69 has a depth K2 to a bottom of 0.1 to 20 μm and a length M2 of one side of the opening 70 of 0.1 to 30 μm, an interval J2 between the openings 70 is 1 to 30 μm, and an interval E2 between the bottoms of the adjacent depressions 69 is 1.1 to 60 μm. Thus, the micro pattern C is formed.

(Negative Mold Manufacturing Step)

As shown in FIG. 13(C), to configure the upper mold 64 with the negative molds 68, the negative molds 68 are arranged and fixed on a lower surface of the upper mold body 67 while surfaces of the negative molds 68 having the micro pattern C are faced up and lateral sides of the molds 68 are contacted with each other. Here, to dispose the negative molds 68 closely-contacted with each other on the upper mold body 67, an interval E2′ between the bottoms of the adjacent regular quadrangular pyramid micro depressions 69 over a border between the adjacent molds 68 must be adjusted to the same value as the interval E2 between the bottoms of the adjacent depressions 69 inside the mold 68. Thereby, continuity of the micro pattern C is ensured between the adjacent negative molds 68. (Assembly step)
Hereinafter, a function of the polishing pad 63 manufactured by using the polishing pad mold 60 will be described.
Since the polishing pad 63 is manufactured by holding and pressing the deformable flat plate in the vertical direction by using the upper mold 64 and the lower mold 65, the polishing pad 63 is provided with high flatness. Also, the micro pattern A is formed on one side of the polishing pad 63. Here, the micro pattern A includes the regular quadrangular pyramid micro protrusions 62 (slope angle θ=30 to 80 degrees), where each of the protrusions 62 having a height H2 to a top of 0.1 to 20 μm, and a length L2 of one side of a base of 0.1 to 30 μm. The protrusions 62 are arranged and disposed on the micro pattern A at an interval D2 of 1.1 to 60 μm between the tops of the adjacent protrusions 62, and at an interval G2 of 1 to 30 μm between bases of the adjacent protrusions 62. Accordingly, a series of operations including cutting a flat plate used as a base material for a polishing pad out of a material for the polishing pad and performing dressing (ensuring flatness of the polishing pad and forming a micro indented pattern) which requires a good skill are no longer necessary. As a result, planarization of the semiconductor substrate 61 can be performed promptly, and polishing performance of the polishing pad 63 can always be maintained constant.
When planalizing the semiconductor substrate 61 by using the polishing pad 63, the polishing pad 63 contacts with a polished surface of the semiconductor substrate 61 via the tops of the regular quadrangular pyramid micro protrusions 62 formed on the polishing pad 63. Thus, slurry including a polishing agent existing in gaps between the protrusions 62 can be efficiently contacted with the polished surface of the semiconductor substrate 61. Further, by feeding the slurry continuously during polishing, the fed slurry passes through the gaps between the protrusions 62, thereby the fresh slurry can always be contacted with the polished surface of the semiconductor substrate 61, and scrapings generated during polishing can be mixed into a flow of the slurry and removed. Here, since no pore exists in a material forming the polishing pad 63, it is possible to prevent the scrapings from entering into the polishing pad 63. As a result, the semiconductor substrate 61 can be planarized stably and efficiently with high precision while a high polishing rate is maintained.
As shown in FIG. 14, a polishing pad mold 81 according to a fourth embodiment of the present invention is used to manufacture a polishing pad strip 83. The polishing pad strip 83 having a micro pattern A is used to planarize a semiconductor substrate 61 (see FIG. 11), an example of a plate-like polished material. The micro pattern A is formed on one side (i.e., side in contact with a processed surface of the semiconductor substrate 61) of the polishing pad strip 83 by arranging regular quadrangular pyramid micro protrusions 82, which are examples of micro protrusions, where each of the protrusions 82 having a height H2 to a top of 0.1 to 20 μm (slope angle θ=30 to 80 degrees) and a length L2 of one side of a base of 0.1 to 30 μm. Here, the regular quadrangular pyramid micro protrusions 82 are arranged and disposed at intervals D2 of 1.1 to 60 μm between the tops of the adjacent protrusions 82 and at intervals G2 of 1 to 30 μm between the bases of the adjacent protrusions 82. Hereinafter, details will be described.
The polishing pad mold 81 includes a pair of an upper roll 85 and a lower roll 86 holding and pressing a deformable strip-like plate 84 in a vertical direction. Here, the strip-like plate 84 (e.g., heated and softened strip-like plate of polyether ether ketone (PEEK), an example of thermoplastic resin) is a material for the polishing pad strip 83, and the micro pattern A is formed on one side of the strip-like plate 84, for example, an upper surface of the strip-like plate 84 by the upper roll 85 and the lower roll 86. Here, a gap corresponding to a thickness of the polishing pad strip 84 is provided between the upper roll 85 and the lower roll 86, and the upper roll 85 and the lower roll 86 revolve in opposite directions during pressing. The upper roll 85 includes a pattern molding portion 87 pressing the upper surface of the strip-like plate 84 to form the micro pattern A on the upper surface by deformation processing, and a roll body 88 retaining the pattern molding portion 87. Further, the pattern molding portion 87 includes a plurality of negative molds 89 disposed (fixed) on a periphery of the roll body 88 with lateral sides of the negative molds 89 closely contacting each other, and the negative molds 89 press the strip-like plate 84 in an integrated fashion to form the micro pattern A.
In each of the negative molds 89, a micro pattern C (pattern having an inverted protrusion-depression shape with respect to the micro pattern A) including regular quadrangular pyramid micro depressions 90, examples of micro depressions, is formed. Here, the regular quadrangular pyramid micro depressions 90 having the inverted protrusion-depression shapes with respect to the regular quadrangular pyramid micro protrusions 82, where each of the depressions 90 having a depth K2 to a bottom of 0.1 to 20 μm, are arranged and disposed at intervals E2 of 1.1 to 60 μm between the bottoms of the adjacent regular quadrangular pyramid micro depressions 90. Also, a length M2 of one side of an opening 91 of the regular quadrangular pyramid micro depression 90 arranged on a surface of the negative mold 89 (the pattern molding portion 87), the periphery of the upper roll 85, is 0.1 to 30 μm, and an interval J2 between the openings 91 is 1 to 30 μm.
In the above-described configuration, by pressing the upper roll 85 from above onto the softened strip-like plate 84 inserted between the upper roll 85 and the lower roll 86 revolving in opposite directions, a part of material composing the strip-like plate 84 enters the regular quadrangular pyramid micro depressions 90 via the openings 91 of the depressions 90 forming the micro pattern C. Thus, on the upper surface of the strip-like plate 84 passed between the upper roll 85 and the lower roll 86, the regular quadrangular pyramid micro protrusions 82 formed by the material entered the regular quadrangular pyramid micro depressions 90 are arranged and disposed, and thereby the micro pattern A is formed. After the strip-like plate 84 (the polishing pad strip 83) having the micro pattern A is cooled and cured, the plate 84 is cut into a predetermined size, and thus the polishing pad 92 is made.
Further, by maintaining a constant gap between the upper roll 85 and the lower roll 86, a distance between the top of each of the regular quadrangular pyramid micro protrusions 82 and a lower surface of the polishing pad strip 83 can be constant (i.e., a thickness of the polishing pad 92 can be uniform). Also, a flat surface contacting with each of the tops of the protrusions 82 can be parallel to the lower surface of the polishing pad strip 83 (i.e., the polishing pad 92).
Hereafter, a method of manufacturing the polishing pad mold 81 according to the fourth embodiment of the present invention will be described. As shown in FIG. 15(A), the method of manufacturing the polishing pad mold 81 includes a positive mold manufacturing step. In the positive mold manufacturing step, regular quadrangular pyramid micro protruding portions 94, examples of micro reactive protrusions, made of ultraviolet curable resin and having the same sizes as the regular quadrangular pyramid micro protrusions 82 are formed on one surface of a flexible flat plate 93 (e.g., silicone resin flat plate, acrylic resin flat plate, glass flat plate), an example of a substrate, in accordance with locations of the protrusions 82 forming the micro pattern A. The micro pattern B including the protruding portions 94 distributed and disposed is thus formed on the one surface of the flat plate 93. Thereafter, the flat plate 93 is bent in an arc in a way that the surface having the micro pattern B is radially inward. Thereby, a positive mold 95 is manufactured. Here, detailed descriptions of a method of forming the regular quadrangular pyramid micro protruding portions 94 are omitted because the method is the same as the method of forming the regular quadrangular pyramid micro protruding portions 73 in the method of manufacturing the polishing pad mold 60 according to the third embodiment of the present invention.
Further, as shown in FIGS. 15(B) and 15(C), the method of manufacturing the polishing pad mold 81 includes a negative mold manufacturing step and an assembly step. In the negative mold manufacturing step, by transferring the micro pattern B of the positive mold 95, the micro pattern C is formed. Here, the micro pattern C includes the regular quadrangular pyramid micro depressions 90, examples of micro depressions, having the same sizes as the regular quadrangular pyramid micro protruding portions 94 and having inverted protrusion-depression shapes with respect to the protruding portions 94, distributed and disposed at locations corresponding to the protruding portions 94. Thus, a negative mold 89 including the micro pattern C is manufactured. In the assembly step, while surfaces of the negative molds 89 having the micro pattern C are faced outward and lateral sides of the molds 89 are contacted with each other, the molds 89 are arranged and fixed on the roll body 88 (e.g., stainless-steel roll, plain steel roll, alloy steel roll, cast iron roll, and non-ferrous metal roll such as aluminum), an example of a basis. Thereby, the upper roll 85 of the polishing pad mold 81 is configured. Details will be described hereinafter.
To manufacture the negative mold 89 by using the positive mold 95, firstly, as shown in FIG. 15(A), an electrode layer 97 made of a metal is formed by PVD (e.g., vapor deposition) on surface having the micro pattern B of the positive mold 95. Next, as shown in FIG. 15(B), on a surface of the electrode layer 97 formed along the surface bent in an arc having the micro pattern B of the positive mold 95 as a base surface, an arc-like metal member 98 having a predetermined thickness of, for example, 0.1 to 5 mm is formed by electroplating. Here, the metal composing the electrode layer 97 must have low adhesion to the ultraviolet curable resin forming the protruding portions 94 and have good adhesion to the arc-like metal member 98. For example, when an acrylic resin or an epoxy resin, etc. is used as the ultraviolet curable resin, the electrode layer 97 is preferably formed by nickel, gold, silver, or copper, etc., and the arc-like metal member 98 is formed by nickel, cobalt, cobalt-nickel alloy, or nickel-phosphorus alloy, etc.
Thereafter, the negative mold 89 is detached from the positive mold 95, and a thickness of the negative mold 89 is adjusted by polishing a surface (opposite to the electrode layer 97) of the arc-like metal member 98. Here, the micro pattern B of the positive mold 95 is transferred onto the electrode layer 97 formed on the positive mold 95. Thus, on the negative mold 89, the regular quadrangular pyramid micro depressions 90 having the inverted protrusion-depression shapes with respect to the regular quadrangular pyramid micro protruding portions 94 (the regular quadrangular pyramid micro protrusions 82) are arranged and disposed. Here, the depression 90 has a depth K2 to a bottom of 0.1 to 20 μm and a length M2 of one side of the opening 91 of 0.1 to 30 μm, an interval J2 between the openings 91 is 1 to 30 μm, and an interval E2 between the bottoms of the adjacent depressions 90 is 1.1 to 60 μm. Thus, the micro pattern C is formed.
To configure the upper roll 85 with the negative molds 89, as shown in FIG. 15(C), the negative molds 89 are arranged and fixed on a periphery of the roll body 88 while surfaces of the negative molds 89 having the micro pattern C are faced up and lateral sides of the molds 89 are contacted with each other. The roll body 88 on which the negative molds 89 are fixed has the same curvature as a curvature of a radially-inward side of the arc-like metal member 98. Here, to dispose the negative molds 89 closely-contacted with each other on the roll body 88, an interval E2′ between the bottoms of the adjacent regular quadrangular pyramid micro depressions 90 over a border between the adjacent molds 89 must be adjusted to the same value as the interval E2 between the bottoms of the adjacent depressions 90 inside the mold 89. Thereby, continuity of the micro pattern C is ensured between the adjacent negative daughter molds 89.

Experimental Example 1

Hereafter, an experimental example to confirm a function and an effect of the method of manufacturing the polishing pad mold according to the first embodiment of the present invention will be described.
A silicon plate having a length of 200 mm, a width of 200 mm, and a thickness of 3 mm was cut out from a monocrystalline silicon rod grown in a [100] direction with a (100) plane as a cutting surface. A resist mask was then formed by using PLP-30 (a commercial product of AZ Electronic Materials) on one side of the silicon plate. Here, the resist mask included a plurality of square holes formed corresponding to shapes and locations of bases of regular quadrangular pyramid micro protrusions of a micro pattern α provided for a polishing pad to be manufactured, a length of one side of the hole was 7 μm, and an interval between the holes was 5 μm. Next, the silicon plate was etched by immersing the silicon plate in an etchant (a tetramethylammonium hydroxide solution of 2.38 wt %) for a predetermined period of time to form regular quadrangular pyramid micro depressions having depths of 4.94 μm and slope angles of 55 degrees. After the silicon plate was removed from the etchant and cleaned, the resist mask was dissolved in acetone and removed. Thereby, a mother mold provided with a micro pattern β having the regular quadrangular pyramid micro depressions arranged with a length of one side of an opening of the depression of 7 μm and an interval between the openings of the adjacent depressions of 5 μm (having an inverted protrusion-depression shape with respect to the micro pattern α) was obtained.
Next, a polypropylene resin plate was heated to 150 to 250° C. to be plastic, and placed on a molding board. The mother mold was then pressed from above to form a micro pattern γ on an upper surface of the polypropylene resin plate by transferring the micro pattern β. Thereby, a positive daughter mold having a length of 200 mm, a width of 200 mm, and a thickness of 3 mm was manufactured.
Thereafter, an electrode layer made of nickel was formed by vapor deposition on a surface having the micro pattern γ of the positive daughter mold, and then a plated metal made of nickel having a thickness of 1 mm was formed by electroplating. Thereby, a negative daughter mold including a micro pattern δ having a length of 200 mm, a width of 200 mm, and a thickness of 1 mm was manufactured.
Next, the manufactured negative daughter molds were arranged and fixed on a lower surface of an upper mold body made of stainless steel while surfaces of the negative daughter molds having the micro pattern δ were faced up and lateral sides of the negative daughter molds were contacted with each other, and thus an upper mold including a pattern molding portion having a length of 1000 mm and a width of 1000 mm was manufactured. Thereafter, by manufacturing a lower mold made of stainless steel having a size corresponding to a size of the upper mold, a polishing pad mold was obtained.
A polyether ether ketone plate (length: 1000 mm, width: 1000 mm, thickness: 4 mm) heated to 400° C. and softened was placed on the lower mold of the polishing pad mold, and then pressed by the upper mold lowered from above to transfer the micro pattern δ on an upper surface of the polyether ether ketone plate. Thereby, a polishing pad including the micro pattern α composed of the regular quadrangular pyramid micro protrusions and having a length of 1000 mm, a width of 1000 mm, and a thickness of 3 mm was made.
A shape of the regular quadrangular pyramid micro protrusion in the micro pattern α formed on the obtained polishing pad was measured. A height of the protrusion was 4.8 to 5.1 μm where a target height was 4.94 μm, a length of one side of a base of the protrusion was 6.8 to 7.2 μm where a target length was 7 μm, and an interval between the protrusions was 4.8 to 5.2 μm where a target interval was 5 μm.
By using the obtained polishing pad, a silicon wafer provided with SiO₂(diameter: 20 mm) was polished by a small polishing machine. Polishing was performed in a way that a surface having the micro pattern α of the polishing pad was rotatably contacted with an upper surface of the silicon wafer with an pressure of 34.5 kPa, and slurry was fed at a rate of 100 ml per minute while the silicon wafer was rotated with a rotation rate of 60 rpm. Here, in the slurry, silica microparticles (polishing agent) of 12.5 mass % were dispersed in potassium hydroxide solution adjusted to pH 11. As a result, a polishing rate was 60 μm/min.
Further, by using a commercially available polishing pad, a silicon wafer of the same size as above was polished under the same polishing conditions as above. Here, a polishing rate was 50 μm/min., and thus polishing performance was almost the same as the polishing pad of the present invention.

Experimental Example 2

Hereafter, an experimental example to confirm a function and an effect of the method of manufacturing the polishing pad mold according to the third embodiment of the present invention will be described.
On one side of a silicon plate having a length of 100 mm, a width of 100 mm, and a thickness of 0.3 mm, a processed layer having a thickness corresponding to a height of a regular quadrangular pyramid micro protrusion in a micro pattern A provided in a polishing pad to be manufactured was formed by using ultraviolet curable resin. Thereafter, by changing an energy amount of ultraviolet irradiation depending on a position in the processed layer, regular quadrangular pyramid micro protruding portions having the same sizes as the regular quadrangular pyramid micro protrusions were formed by a chemical reaction in the processed layer in accordance with locations of the regular quadrangular pyramid micro protrusions. Next, chemically non-reactive regions in the processed layer was dissolved in TMAH and removed. Thereby, a positive mold including the silicon plate having a micro pattern B formed on the one side having the regular quadrangular pyramid micro protruding portions distributed and disposed was manufactured.
Next, after an electrode layer made of nickel having a thickness of 0.1 μm was formed by vapor deposition on a surface of the positive mold having the micro pattern B, a plated metal (a metal plate) made of nickel having a thickness of 0.5 mm was formed by electroplating. Thereby, a negative mold having a length of 100 mm, a width of 100 mm, and a thickness of 0.8 mm and including a micro pattern C was manufactured. Thereafter, the manufactured negative molds were arranged and fixed on a lower surface of an upper mold body made of stainless steel while surfaces of the negative molds having the micro pattern C were faced outward and lateral sides of the negative molds were contacted with each other, and thus an upper mold including a pattern molding portion having a length of 1000 mm and a width of 1000 mm was manufactured. Further, by manufacturing a lower mold made of stainless steel having a size corresponding to a size of the upper mold, a polishing pad mold was obtained.
A polyether ether ketone plate (length: 1000 mm, width: 1000 mm, thickness: 4 mm) heated to 400° C. and softened was placed on the lower mold of the polishing pad mold, and then pressed by the upper mold lowered from above to transfer the micro pattern C on an upper surface of the polyether ether ketone plate. Thereby, a polishing pad including the micro pattern A composed of the regular quadrangular pyramid micro protrusions and having a length of 1000 mm, a width of 1000 mm, and a thickness of 3 mm was made.
A shape of the regular quadrangular pyramid micro protrusion in the micro pattern A formed on the obtained polishing pad was measured. A height of the protrusion was 4.8 to 5.1 μm where a target height was 4.94 μm, a length of one side of a base of the protrusion was 6.8 to 7.2 μm where a target length was 7 μm, and an interval between the protrusions was 4.8 to 5.2 μm where a target interval was 5 μm.
By using the obtained polishing pad, a silicon wafer provided with SiO₂(diameter: 20 mm) was polished by a small polishing machine. Polishing was performed in a way that a surface having the micro pattern A of the polishing pad was rotatably contacted with an upper surface of the silicon wafer with an pressure of 34.5 kPa, and slurry was fed at a rate of 100 ml per minute while the silicon wafer was rotated with a rotation rate of 60 rpm. Here, in the slurry, silica microparticles (polishing agent) of 12.5 mass % were dispersed in potassium hydroxide solution adjusted to pH 11. As a result, a polishing rate was 60 μm/min.
Further, by using a commercially available polishing pad, a silicon wafer of the same size as above was polished under the same polishing conditions as above. Here, a polishing rate was 50 μm/min., and thus polishing performance was almost the same as the polishing pad of the present invention.
Although the present invention is described above by referring to the embodiments, the present invention is not limited to the configurations of the above-described embodiments, and other embodiments and modifications may be made without departing from the scope of claims of the present invention.
Further, the present invention also includes combinations of the components included in each of the above-described embodiments, and other embodiments and modifications.
For example, although the flat plate cut out from the monocrystalline silicon rod grown in the [100] direction is used as the monocrystalline substrate in the polishing pad mold according to the first and the second embodiments, a flat plate cut out from a block of monocrystalline quartz, a flat plate cut out from a block of sapphire, etc. may also be used. Also, although the processed layer is formed by using the ultraviolet curable resin in the polishing pad mold according to the third and the fourth embodiments, acrylic resin, etc. which starts curing by visible light, photocurable glass, etc. which starts curing by infrared, or fluorine resin, etc. which starts curing by electron beam may also be used to form the processed layer. Additionally, the processed layer may also be formed by a process of bond breaking by ultraviolet radiation or by electron beam radiation. Further, although the functions and the effects of the methods of manufacturing the polishing pad molds according to the first and the third embodiments of the present invention are confirmed in the experimental examples 1 and 2, the methods of manufacturing the polishing pad molds according to the second and the fourth embodiments of the present invention also include the same functions and the same effects as above.

REFERENCE SIGNS LIST

10: polishing pad mold, 11: semiconductor substrate, 12: regular quadrangular pyramid micro protrusion, 13: polishing pad, 14: upper mold, 15: lower mold, 16: pattern molding portion, 17: upper mold body, 18: negative daughter mold, 19: regular quadrangular pyramid micro depression, 20: opening, 21: silicon plate, 22: hole, 23: resist mask, 24: regular quadrangular pyramid micro depression, 25: opening, 26: mother mold, 27: positive daughter mold, 29: regular quadrangular pyramid micro protrusion, 30: electrode layer, 31: plated metal, 32: polishing pad mold, 33: regular quadrangular pyramid micro protrusion, 34: polishing pad strip, 34 a: polishing pad, 35: strip-like plate, 36: upper roll, 37: lower roll, 38: pattern molding portion, 39: roll body, 40: negative daughter mold, 41: regular quadrangular pyramid micro depression, 42: opening, 43: silicon plate, 44: hole, 45: resist mask, 46: regular quadrangular pyramid micro depression, 47: opening, 48: mother mold, 49: positive daughter mold, 51: regular quadrangular pyramid micro protrusion, 52: electrode layer, 53: plated metal, 60: polishing pad mold, 61: semiconductor substrate, 62: regular quadrangular pyramid micro protrusion, 63: polishing pad, 64: upper mold, 65: lower mold, 66: pattern molding portion, 67: upper mold body, 68: negative mold, 69: regular quadrangular pyramid micro depression, 70: opening, 71: silicon plate, 72: processed layer, 73: regular quadrangular pyramid micro protruding portion, 74: chemically non-reactive region, 75: positive mold, 76: ultraviolet beam, 77: digital mirror device (DMD), 78: micro mirror, 79: electrode layer, 80: metal plate, 81: polishing pad mold, 82: regular quadrangular pyramid micro protrusion, 83: polishing pad strip, 84: strip-like plate, 85: upper roll, 86: lower roll, 87: pattern molding portion, 88: roll body, 89: negative mold, 90: regular quadrangular pyramid micro depression, 91: opening, 92: polishing pad, 93: flat plate, 94: regular quadrangular pyramid micro protruding portion, 95: positive mold, 97: electrode layer, 98: arc-like metal member

Claims

1. A method of manufacturing a polishing pad mold, the polishing pad mold for manufacturing a polishing pad for planarizing a plate-like material to be polished, one surface of the polishing pad including a micro pattern α having micro protrusions P distributed and disposed at a predetermined interval, the method comprising:

(a) a mother mold manufacturing step, including:

providing a resist mask on one surface of a monocrystalline substrate, the resist mask including holes having the same sizes as sizes of bases of the micro protrusions P, the holes formed in accordance with locations of the micro protrusions P in the micro pattern α; and

etching the one surface of the substrate via the resist mask to form a micro pattern β on the one surface of the substrate, the micro pattern β having micro depressions Q having inverted protrusion-depression shapes with respect to the micro protrusions P, the micro depressions Q distributed and disposed in accordance with the locations of the micro protrusions P in the micro pattern α,

whereby the mother mold including the micro pattern β is manufactured;

(b) a positive daughter mold manufacturing step, including:

transferring the micro pattern β of the mother mold to form a micro pattern γ including micro protrusions R, the micro protrusions R having the same sizes as the micro depressions Q and having inverted protrusion-depression shapes with respect to the micro depressions Q, the micro protrusions R distributed and disposed at locations corresponding to the micro depressions Q,

whereby the positive daughter mold including the micro pattern γ is manufactured;

(c) a negative daughter mold manufacturing step, including:

transferring the micro pattern γ of the positive daughter mold to form a micro pattern δ including micro depressions S, the micro depressions S having the same sizes as the micro protrusions R and having inverted protrusion-depression shapes with respect to the micro protrusions R, the micro depressions S distributed and disposed at locations corresponding to the micro protrusions R,

whereby the negative daughter mold including the micro pattern δ is manufactured; and

(d) an assembly step, including:

arranging and fixing the negative daughter molds on a basis while surfaces of the negative daughter molds having the micro pattern δ being faced outward and while lateral sides of the negative daughter molds being contacted with each other,

whereby the polishing pad mold is configured.

2. The method according to claim 1, wherein the negative daughter mold comprises a metal plate formed by plating on a surface having the micro pattern γ of the positive daughter mold as a base surface, and the basis with the negative daughter mold fixed thereon is a flat plate.

3. The method according to claim 1, wherein the negative daughter mold comprises an arc-like metal member, the arc-like metal member formed by plating on a surface having the micro pattern γ of the positive daughter mold as a base surface, the positive daughter mold being bent in an arc in a way that the surface having the micro pattern γ is radially inward, and the basis with the negative daughter mold fixed thereon is a roll having the same curvature as a curvature of a radially-inward side of the arc-like metal member.

4. A polishing pad mold manufactured by the method according to claim 1.

5. A polishing pad manufactured by using the polishing pad mold according to claim 4.

6. The polishing pad according to claim 5, wherein the substrate is a silicon plate cut out from a monocrystalline silicon rod grown in a [100] direction with a (100) plane as a cutting surface, the resist mask is formed on the (100) plane of the silicon plate, the micro protrusion P is a regular quadrangular pyramid micro protrusion, a length of one side of a base of the regular quadrangular pyramid micro protrusion is 0.1 to 30 μm, and an interval between the adjacent regular quadrangular pyramid micro protrusions is 1 to 30 μm.

7. A method of manufacturing a polishing pad mold, the polishing pad mold for manufacturing a polishing pad for planarizing a plate-like material to be polished, one surface of the polishing pad including a micro pattern A having micro protrusions distributed and disposed at a predetermined interval, the method comprising:

(a) a positive mold manufacturing step, including:

forming a processed layer on one surface of a substrate by using a material chemically reactive with an energy ray for accelerating reaction, the processed layer having a thickness corresponding to a height of the micro protrusion;

forming micro reactive protrusions by a chemical reaction in the processed layer by changing an energy amount of the energy ray for accelerating reaction depending on a position in the processed layer, the micro reactive protrusions having the same sizes as sizes of the micro protrusions, the micro reactive protrusions disposed in accordance with locations of the micro protrusions; and

removing chemically non-reactive regions from the processed layer to form a micro pattern B including the micro reactive protrusions distributed and disposed on the one surface of the substrate,

whereby the positive mold including the micro pattern B is manufactured;

(b) a negative mold manufacturing step, including:

transferring the micro pattern B of the positive mold to form a micro pattern C including micro depressions, the micro depressions having the same sizes as the sizes of the micro reactive protrusions and having inverted protrusion-depression shapes with respect to the micro reactive protrusions, the micro depressions distributed and disposed at locations corresponding to the micro reactive protrusions,

whereby the negative mold including the micro pattern C is manufactured; and

(c) an assembly step, including:

arranging and fixing the negative molds on a basis while surfaces of the negative molds having the micro pattern C being faced outward and while lateral sides of the negative molds being contacted with each other,

whereby the polishing pad mold is configured.

8. The method according to claim 7, wherein the substrate is a flat plate, the negative mold comprises a metal plate formed by plating on a surface having the micro pattern B of the positive mold as a base surface, and the basis with the negative mold fixed thereon is a flat plate.

9. The method according to claim 7, wherein the substrate is a flexible flat plate, the negative mold comprises an arc-like metal member, the arc-like metal member formed by plating on a surface having the micro pattern B of the positive mold as a base surface, the positive mold being bent in an arc in a way that the surface having the micro pattern B is radially inward, and the basis with the negative mold fixed thereon is a roll having the same curvature as a curvature of a radially-inward side of the arc-like metal member.

10. A polishing pad mold manufactured by the method according to claim 7.

11. A polishing pad manufactured by using the polishing pad mold according to claim 10.

12. The polishing pad according to claim 11, wherein a shape of the micro protrusion is a regular quadrangular pyramid, a length of one side of a base of the regular quadrangular pyramid is 0.1 to 30 μm, and an interval between the adjacent regular quadrangular pyramids is 1 to 30 μm.