JP2024024760A - Polishing pad and method for manufacturing the same, and method for manufacturing polished products - Google Patents

Abstract

To provide a polishing pad that is excellent in polishing rate and surface quality of a polished object and a manufacturing method for the same, as well as a manufacturing method for a polished product using the polishing pad.SOLUTION: The polishing pad comprises a polishing layer having a plurality of frustum-shaped protruding parts on the same plane, where in the protruding parts, diameters D1 of upper surfaces which act as polishing surfaces are smaller than diameters D2 of bottom surfaces, and breakage rates of the protruding parts are 30% or less.SELECTED DRAWING: Figure 1A

Description

The present invention relates to a polishing pad, a method for manufacturing the same, and a method for manufacturing a polished product.

Polishing pads are used to polish optical materials, semiconductor devices, glass substrates for hard disks, and the like. A polishing pad is also used when polishing a device in which an oxide layer, metal layer, etc. are formed on a semiconductor wafer. Conventional polishing pads have been used that have a polishing layer made of synthetic resin such as polyurethane, and have concentric or lattice grooves on the surface of the polishing layer. Such a groove shape can contribute to the supply and discharge of polishing slurry during polishing.

In recent years, due to the miniaturization of wiring in semiconductor devices, more precise polishing is required, and polishing pads with even finer irregularities on the polishing surface are also required. For example, Patent Document 1 discloses a method of obtaining a polishing pad by performing fine processing on the surface by micromolding using a master mold made of metal. In the method using such a molding method, a fine uneven pattern can be formed by using a mold having a fine uneven pattern.

Japanese Patent Application Publication No. 2005-74614

However, molds are expensive, and if it is desired to change the pattern of protrusions and recesses, it is necessary to remanufacture an expensive mold. Furthermore, instead of using a mold, a method of forming a concavo-convex pattern on a base material using a screen printing method may be considered. However, the screen printing method has the problem that it is difficult to form a high uneven pattern, and it is difficult to obtain a fine uneven pattern.

Furthermore, it has been found that even if a fine pattern of protrusions and recesses can be formed by a molding method, the shape of the formed protrusions may not be as designed and may be damaged. It is thought that such defects are caused by deepening the concavo-convex pattern in order to increase the height of the convex portion to be molded. For example, by making the pattern of protrusions and recesses deep, when the polishing pad is peeled off from the mold, the tips of the convex portions tend to get caught in the mold, which may cause physical damage. Further, by making the uneven pattern deep, it becomes difficult for the resin to fill the fine recesses of the uneven pattern, which may cause air bubbles to be trapped. By curing in such a state, convex portions with bubble-like defects are generated.

When such defects occur in the convex portions, the contact area between the convex portions of the polishing pad and the object to be polished differs from part to part, resulting in non-uniformity. Furthermore, the convex portions that are damaged during polishing may be broken, or the edges may be increased due to the loss. Therefore, it is assumed that the defects in the convex portions affect the polishing rate and the surface quality of the object to be polished.

The present invention has been made in view of the above problems, and aims to provide a polishing pad with excellent polishing rate and surface quality of an object to be polished, a method for manufacturing the same, and a method for manufacturing a polished product using the polishing pad. purpose.

That is, the present invention is as follows.
[1]
A polishing layer having a plurality of frustum-shaped convex portions on the same plane,
In the convex portion, a diameter D1 of an upper surface serving as a polishing surface is smaller than a diameter D2 of a bottom surface,
The defect rate of the convex portion is 30% or less,
polishing pad.
[2]
The defect rate of the convex portion is 15% or less,
The polishing pad according to [1].
[3]
The defect rate is a defect rate of a convex portion in which the outer shape of the upper surface is defective,
The polishing pad according to [1] or [2].
[4]
The convex portion has a truncated cone shape, and the loss rate is a loss rate of a convex portion whose upper surface is crescent-shaped due to a defect.
The polishing pad according to any one of [1] to [3].
[5]
The convex portion has a truncated polygonal pyramid shape,
The polishing pad according to any one of [1] to [3].
[6]
An angle θ between the side surface of the convex portion and the plane is 105 to 135 degrees,
The polishing pad according to any one of [1] to [5].
[7]
The polishing layer has a Shore D hardness of 30 to 70.
The polishing pad according to any one of [1] to [6].
[8]
The plane has a groove in a region where the convex portion is not provided,
The polishing pad according to any one of [1] to [7].
[9]
The method for manufacturing a polishing pad according to any one of [1] to [8],
a pouring step of pouring the curable composition into an intaglio having a plurality of recesses;
a curing step of curing the curable composition poured into the intaglio to obtain a polishing layer,
The polishing layer has a plurality of frustum-shaped convex portions on the same plane,
In the convex portion, a diameter D1 of an upper surface serving as a polishing surface is smaller than a diameter D2 of a bottom surface,
The defect rate of the convex portion is 30% or less,
Method of manufacturing a polishing pad.

According to the present invention, it is possible to provide a polishing pad with excellent polishing rate and surface quality of an object to be polished, a method for manufacturing the same, and a method for manufacturing a polished product using the polishing pad.

It is a perspective view showing an example of a polishing pad of this embodiment. FIG. 3 is a perspective view showing another example of the polishing pad of the present embodiment. FIG. 3 is a perspective view and a cross-sectional view of a convex portion of the present embodiment. This is a plan view of a convex portion of a truncated quadrangular pyramid with a defect. This is a plan view of a convex portion of a truncated pyramid with a defect. FIG. 2 is a schematic diagram showing an example of a plate making process according to the present embodiment. It is a schematic diagram showing an example of a mold manufacturing process of this embodiment. It is a schematic diagram showing an example of a pouring process, a hardening process, and a peeling process of this embodiment. It is a schematic diagram showing other examples of a pouring process, a hardening process, and a peeling process of this embodiment.

Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail, but the present invention is not limited thereto, and various modifications can be made without departing from the gist thereof. It is.

Regarding the numerical values described in this disclosure, a numerical range may be defined by combining any one of a plurality of upper limit candidate values and any one of a plurality of lower limit candidate values. In addition, even if not specifically mentioned, a numerical range may be defined by combining any two of multiple upper limit candidate values, or by combining any two of multiple lower limit candidate values. Numerical ranges may be defined by combinations.

1. Polishing Pad The polishing pad of the present embodiment includes a polishing layer having a plurality of frustum-shaped convex portions on the same plane, and the convex portion has a diameter D1 of the top surface serving as the polishing surface smaller than a diameter D2 of the bottom surface. , the defect rate of the convex portion is 30% or less.

With this configuration, even if the convex portion is worn out as the polishing progresses, the change in diameter can be reduced. Therefore, even if the wear of the convex portion progresses, it is relatively easy to maintain the surface pressure at the polishing point.

FIGS. 1A and 1B show schematic perspective views of the polishing pad of this embodiment. The polishing pad 1 of this embodiment may include a base material 11 and the polishing layer 12 disposed on the base material 11. In FIG. 1, a plurality of convex portions formed by the polishing layer 12 are arranged on the surface of the base material 11 to form an uneven pattern.

1.1. Polishing Layer As shown in FIGS. 1A and 1B, the polishing layer 12 has a plurality of frustum-shaped convex portions on the same plane. The upper surface of the convex portion becomes a polishing surface for polishing the object to be polished. The polishing layer 12 may form an uneven pattern together with the base material 11 as shown in FIGS. 1A and 1B, or the polishing layer 12 alone may form an uneven pattern.

1.1.1. Convex Portion As shown in FIG. 2A, the convex portion has a diameter D1 of the top surface, which is a polished surface, smaller than a diameter D2 of the bottom surface, and the defect rate of the convex portion is 30% or less.

The truncated cone shape of the convex portion is not particularly limited, and includes, for example, truncated cone shapes such as a truncated cone shape, a substantially truncated cone shape, an elliptical truncated cone shape, and a substantially elliptical truncated cone shape; a polygonal truncated pyramid shape, and the like. It is preferable that the convex portions that come into contact with the object to be polished form a regular pattern. By having a regular pattern, uniform polishing is possible and polishing with excellent surface quality can be achieved. Note that the term "regular pattern" refers to a pattern obtained by arranging a plurality of small patterns serving as units.

FIG. 2B shows a plan view of the convex portion of the truncated square pyramid with the defect. Further, FIG. 2C shows a plan view of a convex portion of a truncated circular pyramid with a defect. In this way, defects in the convex portion can be identified from photographs.

The reason why the defect occurs is not particularly limited, but for example, a transfer failure may occur due to the raw material being poured too quickly during the pouring process described below. Another example is the case where physical defects occur due to poor mold releasability during the peeling process described below. In addition to this, the convex portion may be physically damaged during buffing or groove processing.

In addition, when the resin is cured with air bubbles involved during the pouring process or the curing process, air bubbles may appear as defects. In particular, when the shape of the defective portion is circular as shown in FIG. 2C, the defect tends to be caused by air bubbles. Further, if the shape of the defective portion is other than circular, it may be a physical defect or a combination of a physical defect and a defect due to air bubbles.

From the viewpoint of preventing physical defects, examples include using a mold with excellent mold releasability and using a soft mold. As such a mold, a silicone mold is preferable. In addition, by increasing the angle θ of the convex portion, which will be described later, or by providing a region without a convex portion (a groove, which will be described later), defects tend to be less likely to occur.

Furthermore, from the viewpoint of preventing defects due to air bubbles, the pouring process and the curing process may be performed in a manner that does not involve air bubbles. More specifically, examples include lowering the viscosity of the resin composition to be poured and preventing air bubbles from being mixed in during kneading and pouring of the resin composition.

In this embodiment, the loss rate of such convex portions is 30% or less, preferably 27% or less, 24% or less, 21% or less, It may be 18% or less, 15% or less, 12% or less, 9.0% or less, 6.0% or less, 3 It may be .0% or less. The lower limit of the defect rate of the convex portion may be preferably 0%, 1.0%, 2.0%, or 3.0%. .

The loss rate of convex parts is calculated by visually checking the "number of missing convex parts/number of convex parts" within an unspecified area on a plane, for example using an SEM image, or by performing binarization processing. be able to. Here, the defect rate may be the percentage of the number of convex parts in which the outer shape of the upper surface of the convex part is missing. Moreover, a missing convex portion refers to a convex portion in which 10% or more of the surface area of the upper surface of the convex portion is missing. For example, when the convex portion has a truncated cone shape, the defect rate may be the defect rate of a convex portion whose upper surface is crescent-shaped due to the defect.

In addition, "a convex part where 10% or more of the surface area of the top surface of the convex part is missing" is calculated by comparing the area of the top surface of the convex part with no defects and the area of the top surface of the convex part with defects. can do.

The diameter D1 of the upper surface of the convex portion without defects may preferably be 100 μm or more, 125 μm or more, 150 μm or more, or 175 μm or more. Further, the diameter D1 of the upper surface may preferably be 300 μm or less, 275 μm or less, 250 μm or less, or 225 μm or less.

By adjusting the diameter D1 within the above range, the polishing rate and surface quality tend to be further improved.

The diameter D2 of the bottom surface may preferably be 150 μm or more, 180 μm or more, 200 μm or more, 225 μm or more, 250 μm or more, 275 μm or more, and may be 300 μm or more. The diameter D2 of the bottom surface may preferably be 600 μm or less, 575 μm or less, 550 μm or less, 525 μm or less, 500 μm or less, or 475 μm. 450 μm or less, 425 μm or less, or 400 μm or less.

By setting the diameter D2 to be equal to or greater than the above lower limit value, the convex portion tends to be less likely to break during polishing. Further, by setting the diameter D2 to be equal to or less than the above upper limit value, even if the convex portion is worn out as the polishing progresses, the diameter does not change much, and the surface pressure at the polishing point tends to be maintained relatively easily.

The ratio of diameter D2 to diameter D1 (D2/D1) may be preferably 1.0 or more, 1.1 or more, 1.2 or more, 1.3 or more, may be 1.4 or more, may be 1.5 or more, or may be 1.6 or more. Further, the ratio (D2/D1) may preferably be 2.5 or less, 2.4 or less, 2.3 or less, or 2.2 or less. may be 2.1 or less, 2.0 or less, 1.9 or less, 1.8 or less, 1.7 or less Good too.

By setting the ratio (D2/D1) to the above lower limit value or more, the convex portion tends to be less likely to break during polishing. Further, by setting the ratio (D2/D1) to be equal to or less than the above upper limit value, even if the convex portion is worn out as the polishing progresses, there is little change in the diameter, and the surface pressure at the polishing point tends to be maintained relatively easily.

In addition, each range of the diameter D1, the diameter D2, and the ratio (D2/D1) is any one of the plurality of lower limit candidate values mentioned above and any one of the plurality of upper limit candidate values mentioned above. It may be determined by a combination of two.

The diameter D1 and the diameter D2 are determined by arbitrarily extracting 10 convex points, determining the circle-equivalent diameters of the top and bottom surfaces of each convexity, and taking a weighted average of the obtained circle-equivalent diameters. Calculate the average circle equivalent diameter. The average equivalent circle diameters obtained in this way can be used as the diameter D1 and the diameter D2.

The "circular equivalent diameter" is calculated from the radius r calculated by calculating the area S of the top or bottom surface of the convex part when the polishing pad is viewed from the polishing surface side, and using the following formula (1) based on the area S. be able to. Note that the equivalent circle diameter is 2r. Thereby, the diameter can be calculated even if the top surface and bottom surface are not circular.
Area S=(radius r) ² ×π... (1)

The height H of the convex portion may preferably be 50 μm or more, 75 μm or more, or 100 μm or more. Further, the height H of the convex portion may preferably be 300 μm or less, 275 μm or less, 250 μm or less, 225 μm or less, or 200 μm or less. It may be 175 μm or less, 150 μm or less, 140 μm or less, or 130 μm or less.

By setting the height H to the above lower limit, the product life of the polishing pad is extended, and even if the convex part wears out as polishing progresses, there is little change in diameter, making it relatively easy to maintain the surface pressure at the polishing point. There is a tendency. Further, by setting the height H to be less than or equal to the above upper limit value, the convex portion tends to be less likely to break during polishing.

The angle θ between the side surface of the convex portion and the plane may preferably be 90° or more, 95° or more, 100° or more, or 105° or more. The angle may be 110° or more, or 115° or more. Further, the angle θ may preferably be 150° or less, 145° or less, 140° or less, 135° or less, or 130° or less. The angle may be 125° or less.

Note that when the convex portion has a truncated polygonal pyramid shape or the like and the angle θ varies depending on the side surface, the angle θ is the maximum value among the angles θ around the convex portion.

By setting the angle θ to the above lower limit value or more, the convex portion tends to be less likely to break during polishing. In addition, by keeping the angle θ below the above upper limit, the product life of the polishing pad will be extended, and even if the convex part wears out as polishing progresses, the diameter will not change much, and the surface pressure at the polishing point will be relatively maintained. It tends to be easy.

Note that each range of the height H and the angle θ is determined by a combination of any one of the plurality of lower limit candidate values described above and any one of the plurality of upper limit candidate values described above. Good too.

The density of the convex portions may be expressed by an arbitrarily selected distance L between the centers of the bottom surfaces of adjacent convex portions. The center-to-center distance L may preferably be 300 μm or more, 400 μm or more, 500 μm or more, 600 μm or more, or 700 μm or more. Further, the center distance L may preferably be 2000 μm or less, 1800 μm or less, 1600 μm or less, 1400 μm or less, or 1200 μm or less. , 1000 μm or less, or 800 μm or less. Note that the "center of the bottom surface" of the convex portion refers to the geometric center of the bottom surface.

The distance L between the centers may be preferably 2.0 times or more, 2.25 times or more, or 2.5 times or more with respect to the diameter D1 of the upper surface, It may be 2.75 times or more, 3.0 times or more, or 3.25 times or more. The center-to-center distance L may preferably be 5.0 times or less, 4.75 times or less, or 4.5 times or less with respect to the diameter D1 of the upper surface, It may be 4.25 times or less, 4.0 times or less, 3.75 times or less, or 3.5 times or less.

When the center-to-center distance L is within the above range, it is possible to obtain an uneven pattern in which relatively small convex portions are arranged at a relatively high density, so that the polishing rate tends to be further improved.

Note that each range of the center-to-center distance L may be determined by a combination of any one of the plurality of lower limit candidate values described above and any one of the plurality of upper limit candidate values described above.

1.1.2. Groove The flat surface of the polishing pad of this embodiment may have a groove in a region where no convex portion is provided. FIG. 1B shows a perspective view of a polishing pad in which grooves 13 are formed. Due to the presence of such grooves, slurry tends to be easily supplied to the polishing surface, and polishing debris tends to be easily discharged.

1.1.3. Physical Properties The Shore D hardness of the polishing layer may preferably be 20 or more, 25 or more, 30 or more, 35 or more, or 40 or more. good. The Shore D hardness of the polishing layer may preferably be 80 or less, 75 or less, 70 or less, 65 or less, or 60 or less. .

Note that the range of Shore D hardness may be determined by a combination of any one of the plurality of lower limit candidate values described above and any one of the plurality of upper limit candidate values described above.

1.1.3. Composition The polishing layer may be composed of resin. For example, the polishing layer may be a cured product of a thermosetting composition or a photocurable composition. The polishing layer contains resin and may contain other additives as necessary.

The resin constituting the polishing layer is not particularly limited, but includes, for example, polyurethane resins such as polyurethane having ether or ester bonds in the molecule, polyurethane polyurea, polyurethane acrylate, and addition polymers of amide compounds and isocyanate compounds; bisphenol A; Epoxy resins such as type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolac type epoxy resin; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; unsaturated polyester type Resin: Polyamide resins such as polyetheramide, polyetheresteramide, ammonium salt type tertiary nitrogen atom-containing polyamide; Acrylic resins such as polyacrylate and polyacrylonitrile; Polyvinyl chloride, polyvinyl acetate, polyvinylidene fluoride, etc. Vinyl resins; polysulfone resins such as polysulfone and polyethersulfone; acylated cellulose resins such as acetylated cellulose and butyrylated cellulose; and polystyrene resins. Note that the resin constituting the polishing layer may be used alone or in combination of two or more.

Among these, epoxy resins, unsaturated polyester resins, polyamide resins, and polyurethane resins are preferred. By using such a resin, the polishing rate tends to be further improved.

In addition, when preparing a polyurethane resin, the raw material preferably contains a polyisocyanate and a polyol, and may also contain a urethane prepolymer obtained by reacting a polyisocyanate and a polyol. Moreover, the raw material may contain a curing agent as necessary. This tends to further improve the polishing rate and surface quality.

The structural units derived from polyisocyanates are not particularly limited, and include, for example, structural units derived from alicyclic isocyanates, structural units derived from aliphatic isocyanates, and structural units derived from aromatic isocyanates. Among these, aromatic isocyanates are preferred, and diphenylmethane-4,4'-diisocyanate (MDI) is more preferred.

Examples of alicyclic isocyanates include, but are not limited to, 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI), cyclohexylene-1,2-diisocyanate, cyclohexylene-1,4-diisocyanate, Examples include isophorone diisocyanate.

Examples of aliphatic isocyanates include, but are not limited to, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate (PDI), tetramethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, and trimethylene diisocyanate. , trimethylhexamethylene diisocyanate and the like.

Aromatic isocyanates include, but are not particularly limited to, phenylene diisocyanate, 2,6-tolylene diisocyanate (2,6-TDI), 2,4-tolylene diisocyanate (2,4-TDI), xylylene diisocyanate, Examples include naphthalene diisocyanate and diphenylmethane-4,4'-diisocyanate (MDI).

The structural units derived from polyols are not particularly limited, but include, for example, low-molecular polyols with a molecular weight of less than 300 and high-molecular polyols with a molecular weight of 300 or more. Among these, it is preferable to use at least a low-molecular polyol, and it is preferable to use a low-molecular polyol and a high-molecular polyol in combination.

Examples of low-molecular polyols include, but are not limited to, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, and 1,4-butylene glycol. Butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexane glycol, 2,5-hexanediol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, tricyclode Low-molecular polyols having two hydroxyl groups such as candimethanol and 1,4-cyclohexanedimethanol; low-molecular polyols having three or more hydroxyl groups such as glycerin, hexanetriol, trimethylolpropane, isocyanuric acid, and erythritol. One type of low-molecular polyol may be used alone, or two or more types may be used in combination.

Further, examples of the polymer polyol include, but are not limited to, polyether polyol, polyester polyol, polycarbonate polyol, polyether polycarbonate polyol, polyurethane polyol, epoxy polyol, vegetable oil polyol, polyolefin polyol, acrylic polyol, and vinyl monomer-modified polyol. Examples include polyols. The polymer polyols may be used alone or in combination of two or more.

The number average molecular weight of the high molecular weight polyol is preferably 300 to 1200, more preferably 400 to 950, even more preferably 500 to 800. By using such a polymer polyol, the dynamic viscoelastic properties and D hardness tend to be easily adjusted within the above ranges.

1.2. Substrate The substrate is not particularly limited, and examples thereof include resin-impregnated nonwoven fabric, sponge-like resin foam, and resin film. Examples of the resin include polyurethane resins, polyester resins, polyolefin resins, and the like.

The base material is not particularly limited as long as a resin described below can be formed on the upper surface thereof. Among these, resin-impregnated nonwoven fabrics and sponge-like resin foams are preferred from the viewpoints of chemical resistance, heat resistance, economic efficiency, and the like.

2. Method for manufacturing a polishing pad The method for manufacturing a polishing pad according to the present embodiment includes a pouring step of pouring a curable composition into a mold having a plurality of recesses, and curing the curable composition poured into the mold. , and a curing step to obtain a polishing layer, the polishing layer having the above-described configuration.

Further, in the method for manufacturing a polishing pad of the present embodiment, a mask is formed on the photosensitive resin layer of a plate material including a support and a photosensitive resin layer provided on the support, and the photosensitive resin is applied from the mask side. The method further includes a plate making step of producing an intaglio plate having a concavo-convex pattern by irradiating the layer with light and selectively removing the light-irradiated portions or non-irradiated portions of the photosensitive resin layer. You can.

Furthermore, in the method for manufacturing a polishing pad of the present embodiment, the resin composition for molding is cured in a state in which it is brought into contact with the uneven pattern formed on the intaglio plate obtained in the plate making process, and then the intaglio plate is cured. The method may further include a mold manufacturing step of manufacturing a mold to which the concavo-convex pattern is transferred by peeling off the cured product.

Each step will be described below with reference to FIGS. 3A to 3D.

2.1. Plate making process In the plate making process S1, a mask 33 is formed on the photosensitive resin layer 32 of the plate material 30 including a support 31 and a photosensitive resin layer 32 provided on the support 31, and a mask 33 is formed on the photosensitive resin layer 32 from the mask 33 side. In the process of producing an intaglio plate in which an uneven pattern is formed by irradiating the photosensitive resin layer 32 with light and selectively removing the portions of the photosensitive resin layer 32 that are irradiated with light or the portions that are not irradiated with light. be. In the following description, the photosensitive resin layer 32 that is cured by light irradiation will be explained as an example, but the present invention is not limited thereto.

In the plate making step S1, first, a plate material 30 including a support 31, a photosensitive resin layer 32, and a cover sheet 34 is prepared (S11), and light is irradiated from the support 31 side to the photosensitive resin layer 32. Irradiate (S12). As a result, a portion 32a of the photosensitive resin layer 32 on the side of the support 31 is partially cured.

Next, the cover sheet 34 is peeled off to form a mask 33, and the photosensitive resin layer 32 is irradiated with light from the mask 33 side (S13). As a result, the photosensitive resin layer 32 is partially cured by the light passing through the mask 33. At this time, the photosensitive resin layer 32 cured by exposure from the mask 33 side and the photosensitive resin layer 32 cured by exposure from the support 31 side may constitute an integrated cured product.

Thereafter, the mask 33 is peeled off (S14), and the portions not irradiated with light are selectively removed (S15). As a result, an intaglio plate 40 having an arbitrary uneven pattern formed on the support 31 can be obtained. Note that the support 31 may be peeled off from the intaglio 40.

Here, the plate material is not particularly limited as long as it includes a support and a photosensitive resin layer provided on the support. Here, the material having a photosensitive resin layer and the above-mentioned support is not particularly limited, but for example, after peeling off the cover film to expose the photosensitive resin layer, Printite (trade name) manufactured by Toyobo Co., Ltd. ), Toray (product name) manufactured by Toray Industries, etc.

The photosensitive resin is not particularly limited as long as it undergoes a chemical change under the action of light, resulting in a change in solubility or affinity for a solvent. In this embodiment, the photosensitive resin constituting the photosensitive resin layer includes a resin that undergoes chemical or structural changes when exposed to light, as well as a photosensitizer, etc. even if the resin itself does not have photosensitivity. Also included are resin compositions that can exhibit photosensitivity by being mixed therein.

Such photosensitive resins are not particularly limited, but include, for example, polyether amide, polyether ester amide, ammonium salt type tertiary nitrogen atom-containing polyamide, and amide compounds having one or more amide bonds and organic diisocyanate compounds. Examples include polymers and addition polymers of diamines and organic diisocyanate compounds having no amide bond.

In addition, conventionally known photosensitive resins can be used, such as resins that become insolubilized by photodimerization of functional groups, resins that generate radicals by photolysis of functional groups and become insolubilized by radical recombination, and resins that become insolubilized by photo-dimerization. Photo-insolubilized resins such as resins that become insolubilized through polymerization of molecular monomers; resins that become solubilized by cutting crosslinks when exposed to light, resins that have functional groups whose polarity changes when exposed to light, and resins whose main chains are severed when exposed to light. Examples include photo-solubilized resins such as resins that are solubilized by The photosensitive resins may be used alone or in combination of two or more.

Examples of the support include, but are not limited to, plastic plates such as polyethylene films and polyester films; metal plates such as steel and aluminum; and other plates such as glass. In the case of an intaglio, the support may have a function of supporting a concavo-convex pattern formed by selectively removing the photosensitive resin layer.

The mask partially blocks the light irradiated onto the photosensitive resin layer, and in the plate making process, the pattern of the mask is transferred to the photosensitive resin layer by light irradiation. The mask is not particularly limited as long as it can partially block the light irradiated to the photosensitive resin layer. Alternatively, a mask having a desired pattern may be attached after peeling off the cover film to expose the photosensitive resin layer, or a pattern may be formed on a mask that is attached tightly onto the photosensitive resin layer.

The light to be irradiated is not particularly limited as long as it can change the properties of the photosensitive resin, and examples thereof include ultraviolet light. Furthermore, examples of light sources that emit such light include chemical lamps and ultra-high pressure mercury lamps.

The selective removal of the photosensitive resin layer is not particularly limited as long as it is a method suitable for each photosensitive resin, and examples thereof include washing-out treatment using water or an organic solvent. The intaglio plate thus obtained has an uneven pattern in which the portions of the photosensitive resin layer that are irradiated with light or the portions that are not irradiated with light are selectively removed.

In addition, when the photosensitive resin layer is a photo-insolubilizing resin, the parts that are not irradiated with light are selectively removed, and when the photosensitive resin layer is a photo-solubilizing resin, the parts that are not irradiated with light are removed. selectively remove the parts.

The shape of the uneven pattern can be changed as appropriate depending on the mask used, and the height h (depth or thickness) of the uneven pattern depends on the thickness of the photosensitive resin layer used and the intensity of the irradiated (exposed) light. It can be adjusted as appropriate depending on the situation. The height of the concavo-convex pattern is substantially equal to the height H of the convex portions of the polishing layer. Further, the height of the uneven pattern is synonymous with the depth of the selectively removed photosensitive resin layer.

The obtained intaglio plate may be dried after washing and the like, and then the concavo-convex pattern may be irradiated with light (post-exposure). By performing post-exposure, it is possible to improve the adhesion between the support and the concavo-convex pattern, and to further improve the hardness of the concavo-convex pattern.

2.2. Molding mold manufacturing process In the mold manufacturing process S2, the mold resin composition 41 is cured in a state in which it is brought into contact with the uneven pattern formed on the intaglio plate 40 obtained in the plate manufacturing process S1 (S21). , S22), and by peeling off the cured material 43 from the intaglio 40 (S23), a mold 50 having the concavo-convex pattern transferred thereto is produced.

From the viewpoint of the manufacturing method, the resin composition for the mold is preferably one that cures at a relatively low temperature, and one that provides a cured product with excellent heat resistance and flexibility after curing. Such resin compositions are not particularly limited, but include, for example, room-temperature (low-temperature) curable resin compositions and mixed-type resin compositions that are cured by mixing two liquids.

Among these, those that harden at a low temperature of 130° C. or lower or at room temperature to become a solid rubber are preferred, and those that become a silicone rubber are more preferred. A mold made of such solid rubber is preferable because it has appropriate flexibility and is easily peeled off from the intaglio or the cured product of the curable composition. Moreover, since it is easily peeled off from the intaglio, the cured product of the resin composition for molding mold tends to be difficult to remain on the intaglio.

The method of bringing the resin composition into contact with the concavo-convex pattern formed on the intaglio is not particularly limited as long as the resin composition is filled (poured) into the concave portions of the intaglio, but for example, molding at room temperature and pressure is possible. Examples include a gravity casting method in which the mold composition is poured into the recess by its own weight, and a vacuum casting method in which the mold and resin are placed in a vacuum container, the pressure is reduced, and the composition is poured into the recess at atmospheric pressure.

Moreover, the mold may contain a core material. Having a core material tends to further improve the dimensional stability of the mold. The method for producing a mold containing a core material is not particularly limited, but examples include a method in which the resin composition for the mold is cured in a state in which it is in contact with the core material in the mold manufacturing process, and a method in which the mold resin composition is cured while it is in contact with the core material in the mold manufacturing process; An example of this method is to adhere a core material to the surface opposite to the transfer surface of the uneven pattern.

In addition, as an example of a method of curing the resin composition for molds in a state in which the resin composition for molds is in contact with the core material, after bringing the resin composition for molds into contact with the uneven pattern formed on the intaglio, the resin composition for molds Before curing the object, a core material is bonded to the surface of the molding resin composition opposite to the surface in contact with the intaglio, and the exposed surface of the core material is further covered with the molding resin composition. Accordingly, a core material may be embedded inside the mold.

The core material is not particularly limited, but includes, for example, those having higher mechanical strength than the cured product of the resin composition for molding molds.

The method for curing the resin composition for molds is not particularly limited as long as it is a method suitable for each resin composition for molds, but for example, a curing method in which it is cured by leaving it at room temperature, a method in which it is cured by applying heat, etc. Examples include a curing method, and a method of mixing and leaving as is the case with a two-liquid mixture type. Among these, from the viewpoint of considering the heat resistance of the intaglio plate made of a resin material made of photosensitive resin, those that harden at room temperature are preferred.

Further, from the viewpoint of heat resistance and durability of the intaglio, the temperature of the intaglio during curing of the resin composition for molding is preferably 130°C or lower, more preferably 100°C or lower, and still more preferably 75°C. It is as follows. Moreover, the lower limit of the temperature of the intaglio is not particularly limited, but can be set to 15° C. or higher. By setting the temperature of the intaglio in the mold manufacturing process to 130° C. or lower, deformation of the intaglio due to heat can be suppressed.

The temperature of this intaglio plate is determined not only when the intaglio plate and the curable composition in contact with it are heated by a thermosetting method, but also when a photocuring method and a two-component mixed resin are used. It is preferable to take similar considerations into situations where the intaglio plate may be heated due to temperature increase or heat generation due to reaction.

2.3. Pouring Step The pouring step S31 is a step of pouring the curable composition 51 into the mold 50 having a plurality of recesses. The method of bringing the curable composition into contact with the uneven pattern formed on the mold is not particularly limited as long as the curable composition is filled (poured) into the recesses of the mold, but for example, at room temperature. Examples include a gravity casting method in which the curable composition is poured into the recess by its own weight at normal pressure, and a vacuum casting method in which the mold and resin are placed in a vacuum container, the pressure is reduced, and the curable composition is poured into the recess at atmospheric pressure.

In addition, after bringing the curable composition into contact with the uneven pattern formed on the mold, and before curing the curable composition, the surface of the curable resin opposite to the surface in contact with the mold is coated with a base material. It may further include the step of joining. By using a base material, the curable composition is cured with the curable composition sandwiched between the base material and the mold. This tends to improve the uniformity of the thickness of the obtained cured product and further improve the flatness of the back surface (the surface opposite to the surface in contact with the mold) of the obtained cured product.

Further, the positional relationship between the base material 11 and the mold 50 may be such that the base material 11 does not touch the uneven pattern of the mold 50, as shown in FIG. The material 11 may be in contact with the uneven pattern of the mold 50. When the base material 11 is made not to contact the uneven pattern of the mold 50, the obtained cured product will have convex portions forming the uneven pattern and a support region for connecting the convex portions to each other. . Further, when the base material 11 is brought into contact with the uneven pattern of the mold 50, the obtained cured product becomes a convex part that constitutes the uneven pattern, and the convex part is formed on the base material 11. .

2.4. Curing Step The curing step S32 is a step of curing the curable composition 51 poured into the mold to obtain the polishing layer 12. By curing the curable composition while in contact with the uneven pattern formed on the obtained mold, a cured product of the curable composition to which the uneven pattern has been transferred can be obtained. The surface of the concavo-convex pattern of the cured product obtained in this step (the surface of the convex portions) becomes a polishing surface for polishing the object to be polished.

The curable composition is not particularly limited, but includes, for example, a thermosetting resin; a UV curable resin; a photocurable composition containing a photopolymerization initiator and a polymerizable compound; a photocurable composition containing a thermal polymerization initiator and a polymerizable compound. Thermosetting composition: A curable composition containing a two-liquid mixture type curable resin, etc. may be mentioned. Further, the curable composition may contain a crosslinking agent having two or more polymerizable functional groups, etc., if necessary.

The above-mentioned polymerizable compound is not particularly limited, but includes, for example, an unsaturated carboxylic acid having a polymerizable unsaturated group such as (meth)acrylic acid, itaconic acid, crotonic acid, isocrotonic acid, and maleic acid; (meth)acrylate , epoxy (meth)acrylate, urethane (meth)acrylate, polyester (meth)acrylate, and other unsaturated carboxylic acid esters having polymerizable unsaturated groups; polyesters having unsaturated groups; polyethers having polymerizable unsaturated groups; Examples include polyamide having a polymerizable unsaturated group; urethane having a polymerizable unsaturated group; and aromatic compounds having a polymerizable unsaturated group such as styrene.

The photopolymerization initiator is not particularly limited, but includes, for example, benzophenone compounds, acetophenone compounds, and thiothisanthone compounds. Further, examples of the thermal polymerization initiator include, but are not particularly limited to, azo compounds such as 2,2'-azobisbutyronitrile; peroxides such as methyl ethyl ketone peroxide and benzoyl peroxide (BPO). .

Examples of the thermosetting resin include, but are not limited to, phenol resins, epoxy resins, acrylic resins, urethane resins, formaldehyde resins, and the like.

The UV curable resin is not particularly limited, but for example, a prepolymer having a number average molecular weight of about 1,000 to 10,000 is preferable, and examples of the material include acrylic (methacrylic) ester resins, urethane-modified resins thereof, thiocol resins, etc. , a reactive diluent or an organic solvent can be used as appropriate depending on the application.

Furthermore, the two-liquid mixture type cured resin is not particularly limited, but for example, prepolymers with different physical properties can be used, and examples thereof include epoxy resin, unsaturated polyester resin, polyamide resin, and the like.

Among these, from the viewpoint of considering the heat resistance of the mold, those that harden at room temperature are preferred. Such curable compositions are not particularly limited, but include, for example, curable compositions containing a polymerization initiator that act at room temperature, UV curable resins and photocurable compositions that cure by light irradiation, and two-part curable compositions. Examples include mixed-type curable compositions that are cured by mixing.

The method of curing the curable composition is not particularly limited as long as it is a method suitable for each curable composition, but examples include a photo-curing method of irradiating ultraviolet rays, etc., a thermo-curing method of applying heat (such as leaving it at room temperature). (including a method in which the liquid is mixed), or a method in which the mixture is mixed and left as is the case with a two-liquid mixture type.

The curing step may be performed using multiple molds. Similar to the mold manufacturing process, if the size of the polishing pad to be manufactured is larger than one mold, combine multiple molds to create a mold of the desired size, and then combine them. A cured product (polishing layer) can be formed using a mold. Thereby, there is no need to create a mold according to the size of the polishing pad, and it is possible to omit the process of creating molds of various sizes, thereby further reducing manufacturing costs. Further, in the above example, a rectangular mold was used, but in this case, if a circular polishing pad is to be obtained, the obtained cured product (polishing layer) may be cut into a circular shape.

2.5. Peeling Step The peeling step S33 is a step of peeling off the cured product from the mold 50 to obtain the polishing layer 12. The polishing layer 12 obtained in this step has a concavo-convex pattern transferred from the mold 50, and the surface of the convex portions of the concave-convex pattern becomes a polishing surface for polishing the object to be polished. Furthermore, the method may further include a step of attaching the base material 11 to the polishing layer 12 obtained in the peeling step using double-sided tape or the like.

By such a method, in this embodiment, a polishing pad having a concavo-convex pattern with a sufficient height can be easily manufactured at a lower cost without going through a cutting process.

3. Method for manufacturing a polished product The method for manufacturing a polished product according to the present embodiment is not particularly limited as long as it includes a polishing step of polishing an object to be polished using the polishing pad in the presence of free abrasive grains. . The polishing process may be primary lapping (rough lapping), secondary lapping (finish lapping), or polishing. You can.

The object to be polished is not particularly limited, but includes, for example, materials such as semiconductor devices and electronic components, particularly Si substrates (silicon wafers), SiC (silicon carbide) substrates, GaAs (gallium arsenide) substrates, glass, hard disks, and LCDs. Examples include thin substrates (objects to be polished) such as substrates for (liquid crystal displays). Among these, the method for manufacturing a polished product of the present embodiment is a method for manufacturing difficult-to-process materials that are difficult to polish, such as materials that can be applied to power devices, LEDs, etc., such as sapphire, SiC, GaN, and diamond. It can be suitably used as Among these, a semiconductor wafer is preferred, and a SiC substrate, a sapphire substrate, or a GaN substrate is preferred, from the viewpoint of more effectively utilizing the effects of the polishing pad of this embodiment. As for the material, difficult-to-cut materials such as SiC single crystal and GaN single crystal are preferred, but single crystals such as sapphire, silicon nitride, and aluminum nitride may also be used.

3.1. Polishing Process The polishing process is a process of polishing an object to be polished using the polishing pad described above in the presence of free abrasive grains. As the polishing method, a conventionally known method can be used and is not particularly limited.

In the polishing method, first, a polishing pad is attached to a predetermined position of a polishing device. During this mounting, the polishing pad is fixed to the polishing device via the adhesive layer described above. Then, the object to be polished, which is held on a holding surface plate arranged to face the polishing pad as a polishing surface plate, is pressed against the polishing surface side, and while a polishing slurry containing abrasive grains is supplied from the outside, the polishing pad is and/or rotating the holding surface plate. As a result, the processed surface (surface to be polished) of the object to be polished is polished by the action of the abrasive grains supplied between the polishing pad and the object to be polished.

The present invention has industrial applicability as a polishing pad for polishing semiconductor devices and the like.

DESCRIPTION OF SYMBOLS 1... Polishing pad, 11... Base material, 12... Polishing layer, 13... Groove, 30... Plate material, 31... Support body, 32... Part, 32... Photosensitive resin layer, 32a... Part, 33... Mask, 34 ... cover sheet, 40 ... intaglio, 41 ... resin composition for molding mold, 43 ... cured product, 50 ... mold, 51 ... curable composition

Claims (9)

A polishing layer having a plurality of frustum-shaped convex portions on the same plane,
In the convex portion, a diameter D1 of an upper surface serving as a polishing surface is smaller than a diameter D2 of a bottom surface,
The defect rate of the convex portion is 30% or less,
polishing pad. The defect rate of the convex portion is 15% or less,
The polishing pad according to claim 1. The defect rate is a defect rate of a convex portion in which the outer shape of the upper surface is defective,
The polishing pad according to claim 1. The convex portion has a truncated cone shape, and the loss rate is a loss rate of a convex portion whose upper surface is crescent-shaped due to a defect.
The polishing pad according to claim 1. The convex portion has a truncated polygonal pyramid shape,
The polishing pad according to claim 1. An angle θ between the side surface of the convex portion and the plane is 105 to 135 degrees,
The polishing pad according to claim 1. The polishing layer has a Shore D hardness of 30 to 70.
The polishing pad according to claim 1. The plane has a groove in a region where the convex portion is not provided,
The polishing pad according to claim 1. A method for manufacturing a polishing pad according to any one of claims 1 to 8, comprising:
a pouring step of pouring the curable composition into an intaglio having a plurality of recesses;
a curing step of curing the curable composition poured into the intaglio to obtain a polishing layer,
The polishing layer has a plurality of frustum-shaped convex portions on the same plane,
In the convex portion, a diameter D1 of an upper surface serving as a polishing surface is smaller than a diameter D2 of a bottom surface,
The defect rate of the convex portion is 30% or less,
Method of manufacturing a polishing pad.