Polishing pad and method of manufacturing same

Abstract

To provide a method for manufacturing a polishing pad, which can easily manufacture a polishing pad at lower cost without going through a cutting step, and to provide the polishing pad. [Solution] A method for manufacturing a polishing pad, comprising: a plate making step of forming a mask 4 on the photosensitive resin layer of a plate material having a support 2 and a photosensitive resin layer 1 provided on the support, irradiating light from the mask side onto the photosensitive resin layer, and selectively removing the light-irradiated portions 1a or the non-light-irradiated portions 1b of the photosensitive resin layer to form an embossed plate 5 on which an embossed pattern 6 is formed; a curing step of contacting a curable composition 7 with the embossed pattern formed on the obtained embossed plate and curing the composition to obtain a cured product of the curable composition to which the embossed pattern has been transferred; and a peeling step of peeling the cured product from the embossed plate to obtain a polishing layer.

Description

[Technical field]

[0001] The present invention relates to a polishing pad and a method for manufacturing the same. [Background technology]

[0002] For lapping and polishing of optical materials, semiconductor devices, glass substrates for hard disks, etc. In this case, polishing is performed using a polishing pad. Polishing pad, polishing pad using foamed or non-foamed polyurethane, polishing pad having fixed abrasive grains Various types of polishing pads are available, including polishing pads that use a resin layer with a concave-convex pattern as the polishing surface. Things are known.

[0003] Among these, the polishing pad using a resin layer having a concave-convex pattern as a polishing surface is called the concave-convex pattern. The grooves formed by the turns affect the fluidity of the slurry, resulting in uniform polishing of the workpiece. The advantage of this method is that the surface of the flat base material can be polished. A method of forming grooves by cutting the surface, or a method of applying screen printing to create a concave and convex pattern on the substrate. A method for forming a mold by using a mold having a concave-convex pattern is provided. A molding method is mentioned.

[0004] For example, in Patent Document 1, in a method of forming grooves by cutting, the groove width and groove depth are There is a limit to how much smaller dimensions can be made, so a metal master mold is used to create a microphone. A method for manufacturing a polishing pad by micro-machining the surface using a romolding method is disclosed. In such a molding method, a mold having a fine concave-convex pattern is used. This allows the creation of fine uneven patterns that require micromachining, which is difficult to achieve using conventional cutting processes. It is believed that this can be achieved. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2005-74614 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, when using a metal mold as in Patent Document 1, the manufacturing process of the mold is In order to manufacture the product, fine machining such as cutting is required, and in the end, cutting is completely eliminated. In addition, the mold is expensive and difficult to use. In addition to the disadvantage of this, when you want to change the unevenness pattern, such as the width or depth of the groove, In such a case, it would be necessary to create a new expensive mold, making this unrealistic.

[0007] In addition, the method of forming a concave-convex pattern on a substrate by screen printing involves a cutting process. It is possible to form a concave-convex pattern without applying any adhesive to the substrate by screen printing. The dot-shaped resin (protrusions) formed on the substrate tend to spread over the substrate due to their own weight and viscosity. Therefore, there is a limit to obtaining a concave-convex pattern having high convexities. The convex parts of the polishing surface tend to be worn away during polishing, and the polishing rate gradually decreases. If the groove depth is shallow, the polishing rate drops quickly, shortening the product life of the polishing pad. There is a problem of not being able to secure enough life.

[0008] The present invention has been made in consideration of the above problems, and is a method for manufacturing a metal mold without a cutting process and at a lower cost. Method for manufacturing a polishing pad capable of easily forming a concave-convex pattern having a sufficient height in a test The present invention provides a method for producing a polishing pad using the method. [Means for solving the problem]

[0009] The present inventors have conducted extensive research into the above-mentioned problems. It has been found that the above problems can be solved by a method for forming a relief plate using a material. The invention has been completed.

[0010] That is, the present invention is as follows. [1] A method for producing a polishing pad having a polishing layer formed by curing a curable composition, comprising the steps of: A plate material including a support and a photosensitive resin layer provided on the support, A mask is formed on the photosensitive resin layer, and light is irradiated onto the photosensitive resin layer from the mask side. By selectively removing the areas where light was irradiated or where light was not irradiated, a concave-convex pattern is created. a plate making process for making a relief plate having a turn formed thereon; The curable composition is brought into contact with the concave-convex pattern formed on the obtained concave-convex plate. The curable composition having the concave-convex pattern transferred thereto is then cured in the above-mentioned state. a curing step for obtaining a cured product; a peeling step of peeling the cured product from the relief plate to obtain an abrasive layer; having A method for manufacturing a polishing pad. [2] In the curing step, the temperature of the relief plate is 130° C. or less. A method for producing the polishing pad described in [1]. [3] A polishing layer is provided which is formed by curing a curable composition, The bending strength of the polishing layer is 50 MPa or more. Polishing pad. [4] The polishing layer is a concave-convex plate having a support area and a convex portion formed on the support area. having a turn, The polishing pad according to [3]. Effect of the Invention

[0011] According to the present invention, a recess having a sufficient height can be easily formed at low cost without a cutting process. Method for manufacturing a polishing pad capable of forming a convex pattern, and a polishing pad manufactured by the method In accordance with the present invention, a polishing pad having a polishing surface can be provided. [Brief description of the drawings]

[0012] [Figure 1] 3A to 3C are process diagrams of a method for manufacturing a polishing pad according to the present embodiment. [Diagram 2] FIG. 11 is a process diagram showing another embodiment of the curing process. [Diagram 3] FIG. 13 is a top view showing an example of use of a relief plate when multiple relief plates are used. [Figure 4] FIG. 11 is a process diagram showing an example of a curing process using a plurality of relief plates. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention (hereinafter, referred to as "the present embodiment") will be described in detail. However, the present invention is not limited to this, and various modifications can be made without departing from the spirit and scope of the present invention. It is possible.

[0014] [Method of manufacturing polishing pad] The method for producing a polishing pad of the present embodiment includes producing a polishing pad having a polishing layer formed by curing a curable composition. A method for manufacturing a polishing pad, comprising: A mask is formed on the photosensitive resin layer of the printing plate, and light is applied to the photosensitive resin layer from the mask side. and selectively removing the irradiated and non-irradiated portions of the photosensitive resin layer. a plate making process for making a relief plate having a relief pattern formed thereon by removing the A state in which the curable composition is brought into contact with the relief pattern formed on the relief plate. and curing the curable composition with the concave-convex pattern transferred thereto. and peeling the cured product from the relief plate to obtain an abrasive layer. and a peeling step.

[0015] As described above, in the conventional method using a metal mold, cutting work is completely eliminated. This is problematic from the viewpoint of cost, and the width and depth of the grooves cannot be adjusted. In addition, the method using screen printing, etc. However, there is a problem in that it is difficult to obtain a concave-convex pattern having high convexities.

[0016] In contrast, in the method for producing a polishing pad according to the present embodiment, a photosensitive resin layer is provided. A relief plate having a desired relief pattern can be obtained relatively easily from the plate material, and the obtained relief plate is By using it as a mold, it is possible to efficiently obtain a polishing layer having any desired uneven pattern. In addition, the concave and convex patterns can be easily changed. In the manufacturing method of the polishing pad, the relief plate once produced is repeatedly subjected to the curing process. This allows the production efficiency to be further improved.

[0017] FIG. 1 shows a flow chart of the method for manufacturing a polishing pad according to the present embodiment. As shown in FIG. In the method for producing a polishing pad according to the present embodiment, a photosensitive resin layer 1 and a support 2 are provided. A printing plate 3 is used, and light is irradiated onto the printing plate 3 through a mask 4, thereby performing cutting processing, etc. The relief plate 5 can be obtained without going through the above steps. In accordance with the present invention, various uneven patterns 6 can be formed. In the subsequent curing step, the uneven pattern of the uneven plate 5 is The pattern 6 is transferred with high accuracy to the cured product of the curable composition 7. The polishing pad 10 having the polishing layer 9 obtained by the method is much more It is possible to form a concave-convex pattern 11 having deep grooves. In the embodiment shown, the light irradiated portion 1a remains to form the concave-convex pattern 6 of the concave-convex plate 5. However, as will be described later, the portion 1b that is not irradiated with light remains, and the uneven pattern of the relief plate 5 is not formed. Alternatively, a step 6 may be formed. Each step will be described in more detail below.

[0018] [Plate making process] The plate making process is a process for producing a plate material having a support and a photosensitive resin layer provided on the support. A mask is formed on the oil layer, and the photosensitive resin layer is irradiated with light from the mask side. By selectively removing the areas where light was irradiated or the areas where light was not irradiated, a concave-convex pattern is obtained. This is the process of producing a relief plate on which patterns are formed.

[0019] The printing plate may be any material having a support and a photosensitive resin layer provided on the support. Here, the photosensitive resin layer and the support are not particularly limited. For example, after peeling off the cover film to expose the photosensitive resin layer, Examples of such products include Printite (product name) manufactured by Toray Industries, Inc., and Toray Relief (product name) manufactured by Toray Industries, Inc.

[0020] Photosensitive resins undergo chemical changes when exposed to light, resulting in a decrease in solubility in solvents. There are no particular limitations as long as the affinity is changed. The photosensitive resin that constitutes the resin layer is a resin that undergoes chemical or structural changes when exposed to light. In addition to fats, even if the resin itself does not have photosensitivity, it can be made photosensitive by mixing a photosensitizer. The resin composition also includes a resin composition capable of exerting the above-mentioned effects.

[0021] Such photosensitive resins are not particularly limited, but examples thereof include polyether amides, Polyether ester amide, ammonium salt type tertiary nitrogen atom-containing polyamide, amide bond Addition polymer of an amide compound having one or more bonds and an organic diisocyanate compound, an amide bond Examples of the copolymer include an addition polymer of a diamine having no copolymer and an organic diisocyanate compound.

[0022] The photosensitive resin may be a conventionally known one, and may be rendered insoluble by photodimerization of the functional group. Resins that become insoluble through photolysis of functional groups to generate radicals and then recombine radicals to become insoluble. photoinsolubilizable resins, such as resins in which low molecular weight monomers are polymerized and insolubilized by exposure to light; Resins that become soluble by breaking cross-linking bonds, and resins that have functional groups whose polarity changes when irradiated with light. Photosolubilizable resins, such as resins that are soluble when the main chain is cut by irradiation with light. The photosensitive resin may be used alone or in combination of two or more kinds.

[0023] The support is not particularly limited, but may be, for example, a polyethylene film or a polyester film. Plastic plates such as films; metal plates such as steel and aluminum; glass and other When the support is used as a relief plate, the photosensitive resin layer is selectively It may have a function of supporting the concave-convex pattern that is formed by removing it.

[0024] The mask partially blocks the light irradiated onto the photosensitive resin layer and is used in the plate making process. The pattern of the mask is transferred to the photosensitive resin layer by light irradiation. There are no particular limitations as long as the light irradiated to the photosensitive resin layer can be partially blocked. In addition, the cover film is peeled off to expose the photosensitive resin layer, and then a mask having a desired pattern is formed. The mask is attached to the photosensitive resin layer, and a pattern is formed on the mask attached to the photosensitive resin layer. So that's fine.

[0025] The light to be irradiated may be any light capable of changing the properties of the photosensitive resin. Examples of the light include, but are not limited to, ultraviolet light. Examples of the light source include a chemical lamp and an ultra-high pressure mercury lamp.

[0026] The selective removal of the photosensitive resin layer can be carried out by any method suitable for each photosensitive resin. Although not limited thereto, examples thereof include a washing treatment using water or an organic solvent. The relief plate obtained by this method has a photosensitive resin layer in which the light is irradiated and the light is not irradiated. The uneven pattern has a portion where the uneven portion is selectively removed. The height h (depth or thickness) of the concave-convex pattern can be changed appropriately by using a mask. ) should be adjusted appropriately depending on the thickness of the photosensitive resin layer used and the intensity of the irradiated (exposed) light. The height h of the uneven pattern is substantially equal to the height of the protrusions 11a of the polishing layer ( In addition, the height h of the concave-convex pattern is equivalent to the depth of the selectively removed photosensitive resin layer. become.

[0027] The obtained relief plate is washed out and then dried. It is also possible to irradiate the substrate with light (post-exposure). Post-exposure improves adhesion between the substrate and the concave-convex pattern. This can improve the adhesion and hardness of the concave-convex pattern.

[0028] [Curing process] In the curing step, a curable composition is brought into contact with the concave-convex pattern formed on the obtained concave-convex plate. By curing the curable composition in this state, a cured product having a concave-convex pattern transferred thereto is obtained. The surface of the concave-convex pattern of the cured product obtained in this step (the surface of the convex portions) is It serves as an abrasive surface for abrading an object.

[0029] The curable composition is not particularly limited, but may be, for example, a thermosetting resin; a UV-curable resin; Photocurable compositions containing a photopolymerization initiator and a polymerizable compound; Thermal polymerization initiator and a polymerizable compound and a curable composition containing a two-liquid mixed curable resin. The curable composition may contain, as necessary, a crosslinking agent having two or more polymerizable functional groups. .

[0030] The polymerizable compound is not particularly limited, but examples thereof include (meth)acrylic acid, ita Unsaturated acids having polymerizable unsaturated groups such as crotonic acid, crotonic acid, isocrotonic acid, and maleic acid Saturated carboxylic acids; (meth)acrylates, epoxy (meth)acrylates, urethane (meth)acrylates (p) Unsaturated acrylates having polymerizable unsaturated groups such as polyester (meth)acrylates Polyesters containing unsaturated groups; Polyesters containing polymerizable unsaturated groups Polyamides having polymerizable unsaturated groups; Urethanes having polymerizable unsaturated groups; Styrene Examples of the aromatic compounds include aromatic compounds having a polymerizable unsaturated group such as phenylene.

[0031] The photopolymerization initiator is not particularly limited, but examples thereof include benzophenone-based compounds, Acetophenone compounds and thioxanthones. Thermal polymerization initiators and Examples of the azo bisbutyronitrile include, but are not limited to, azo bisbutyronitrile such as 2,2'-azobisbutyronitrile. Compounds; peroxides such as methyl ethyl ketone peroxide and benzoyl peroxide (BPO) Examples include:

[0032] The thermosetting resin is not particularly limited, but examples thereof include phenol resin and epoxy resin. , acrylic resin, urethane resin, formaldehyde resin, etc.

[0033] The UV-curable resin is not particularly limited, but may be, for example, a resin having a number average molecular weight of 1000 to 10 A prepolymer with a molecular weight of about 000 is preferable, and the material is an acrylic (methacrylic) ester. Resins, urethane modified resins, thiokol resins, etc. are available, and the reactivity can be adjusted according to the application. A diluent or organic solvent may be used.

[0034] In addition, the two-liquid mixed curable resin is not particularly limited, but may be, for example, a polymer having different physical properties. Repolymers can be used, such as epoxy resins, unsaturated polyester resins, and polyamides. Resins and the like.

[0035] Among these, from the viewpoint of the heat resistance of the relief printing plate, those which harden at room temperature are preferred. Such a curable composition is not particularly limited, but for example, Curable composition containing a polymerization initiator, UV-curable resin cured by irradiation with light, and photocurable composition and mixed-type curable compositions which are cured by mixing two liquids.

[0036] The method for contacting the curable composition with the concave-convex pattern formed on the concave-convex plate is as follows: There are no particular limitations as long as the curable composition is filled (poured) into the recesses of the plate. For example, For example, a gravity casting method is used in which the hardening composition is poured into the recess by its own weight at room temperature and normal pressure, and a mold and resin are used. One method is vacuum casting, in which the fat is placed in a vacuum container, the pressure is reduced, and the fat is poured into the recesses at atmospheric pressure.

[0037] In addition, after the concave-convex pattern formed on the concave-convex plate is brought into contact with the curable composition, Before the composition is cured, a substrate is bonded to the surface of the curable resin opposite to the surface that contacts the relief plate. By using a substrate, the curable composition may be bonded to the substrate and the relief plate. The curable composition is cured in the state where the two are sandwiched. The thickness uniformity is improved, and the back surface of the resulting cured product (the surface opposite to the surface in contact with the relief plate) The flatness tends to be improved. The positional relationship between the substrate and the relief plate is as shown in Figure 1. As shown in FIG. 2, the substrate 8 may be prevented from contacting the concave-convex pattern 6 of the concave-convex plate 5. In this way, the substrate 8 may be in contact with the concave-convex pattern 6 of the concave-convex plate 5. When the plate 5 is not in contact with the concave-convex pattern 6, the resulting cured product is 1, and a support region 11b for connecting the protrusions to each other. In addition, when the substrate 8 is in contact with the concave-convex pattern 6 of the concave-convex plate 5, the obtained The cured product becomes the convex portions 11a that constitute the concave-convex pattern 11, and the convex portions 11a are formed on the substrate 8. It will be something that is done.

[0038] The method for curing the curable composition may be any method suitable for each curable composition. However, the present invention is not limited to the above. For example, the photo-curing method includes irradiating ultraviolet rays, and the thermal curing method includes applying heat. (including leaving it at room temperature) or mixing two-liquid mixtures and leaving them alone. can be.

[0039] The relief pattern of the relief plate of this embodiment is made of a resin material made of a photosensitive resin. Therefore, from the viewpoint of heat resistance and durability of the relief printing plate, The temperature is preferably 130° C. or less, more preferably 100° C. or less, and The temperature is preferably 75° C. or less. The lower limit of the temperature of the relief plate is not particularly limited, but is preferably 15° C. The temperature of the relief plate in the curing step is 130°C or less. This makes it possible to suppress deformation of the relief plate due to heat. In addition to the case where the relief plate and the curable composition in contact with it are heated by the photo-curing method, When using a two-liquid mixed resin, heat is generated by heating due to light irradiation or reaction. It is preferable that the same consideration be given to a situation in which the relief plate may be heated by the opening of the recess.

[0040] The curing step may be performed using a plurality of relief plates. A top view showing an example of the use of is shown in FIG. 3, and an example of a curing process using multiple relief plates is shown in FIG. As shown in FIG. 3, the size of the polishing pad to be produced is larger than one of the relief plates 5a to 5i. In this case, a plurality of relief plates 5a to 5i are used in combination to produce a relief plate of a desired size. After that, the combined relief plates can be used to form a hardened material (abrasive layer) (Fig. 3). This eliminates the need to create a embossed plate according to the size of the polishing pad. This makes it possible to omit the process of producing various sizes of relief plates, further reducing manufacturing costs. In the above example, the rectangular relief plates 5a to 5i are illustrated. In the case of the above, when a circular polishing pad is to be obtained, the obtained cured product (polishing layer) is cut into a circular shape. You may cut it out.

[0041] [Peeling process] The peeling step is a step of obtaining an abrasive layer by peeling off the cured product from the relief plate. The polishing layer obtained in this step has a concave-convex pattern transferred from the concave-convex plate. The surface of the convex portion of the turn becomes the polishing surface for polishing the workpiece.

[0042] [Polishing pad] The polishing pad of the present embodiment is obtained by the above-mentioned manufacturing method, and is a curable composition The polishing layer has an uneven pattern having an arbitrary shape and a sufficient height. The bending strength of the polishing layer is 50 MPa, preferably 50 to 1000. MPa, more preferably 55 to 900 MPa, and further preferably 60 to 80 The bending strength is measured according to JIS K7203. By having the bending strength within the above range, the polishing layer can be easily peeled off from the relief plate during the peeling step. This makes it possible to suppress damage and deformation of the polishing layer when peeling it off.

[0043] The polishing layer may have a projection-recess structure in which the support area and the projections formed on the support area are integrally molded. It is preferable that the protrusion and the support area are integrally molded. This eliminates the need for a process for joining the protrusions and the support area, thereby reducing costs. Compared to when the protrusion and the support area are bonded together, the bond strength is higher and the protrusion cannot be removed from the support area. It becomes more difficult. EXAMPLES

[0044] The following describes the height of the uneven pattern, the degree of freedom in designing the uneven pattern, and the simplicity of the manufacturing method ( From the viewpoint of the above, the method for manufacturing a polishing pad according to the present embodiment, Qualitative description of the method for producing a polishing pad by screen printing was rated.

[0045] As a result, in the manufacturing method that involves a step using a mold, a relatively high concave-convex pattern is produced. However, the design freedom of the concave-convex pattern is low, and it is difficult to create a precise metal pattern. Since it is necessary to create a mold, the manufacturing process is not very simple. This is not limited to a metal mold, but is similar to the case where a resin mold that does not use a photosensitive resin is used.

[0046] In addition, the screen printing method has a limit to the height of the uneven pattern, From the viewpoint of life, it is difficult to form the desired concave-convex pattern.

[0047] In comparison, the method for producing a polishing pad according to the present embodiment is simple and inexpensive. It was possible to form a concave-convex pattern having a sufficient height. [Industrial Applicability]

[0048] The method for producing a polishing pad of the present invention is for producing a polishing pad for optical materials, semiconductor devices, and hard disks. The present invention has industrial applicability as a method for producing polishing pads for use in lapping and polishing glass substrates, etc. It has potential. [Explanation of symbols]

[0049] 1: photosensitive resin layer, 1a: light irradiated portion, 1b: non-light irradiated portion, 2: support Body, 3... printing material, 4... mask, 5, 5a to 5i... relief plate, 6... relief pattern, 7... curable composition object, 8...substrate, 9...polishing layer, 10...polishing pad, 11...concave-convex pattern, 11a...convex portion, 1 1b…Support area

Claims

1. The polishing layer is formed by curing a curable composition (excluding those formed from foamed polyurethane), The curable composition contains a thermosetting resin, a photocurable composition, a thermosetting composition, or a two-liquid mixed curable resin (excluding acetyl cellulose), The polishing layer has a concave-convex pattern, the surface of the concave-convex pattern is a polishing surface for polishing an object to be polished, The bending strength of the polishing layer is 50 MPa or more. Polishing pad.

2. The polishing layer has a concave-convex pattern in which a support region and a convex portion formed on the support region are integrally molded.

2. The polishing pad of claim 1.

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