JP2002324770A - Polishing pad for semiconductor wafer, polishing multilayer body for semiconductor wafer including the same, and method for polishing semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing pad for a semiconductor wafer, a polishing multilayer body for a semiconductor wafer, and a method for polishing a semiconductor wafer using the same, which can detect an optical end point without deteriorating polishing performance. I will provide a. SOLUTION: 80% by volume of 1,2-polybutadiene serving as a matrix material and 20% by volume of β-cyclodextrin serving as water-soluble particles are kneaded in a heated kneader, and further kneaded by adding a crosslinking agent. After that, a crosslinking reaction was performed in a press mold for a predetermined time, followed by molding to obtain a polishing pad. When the obtained polishing pad has a thickness of 2 mm, the transmittance at any wavelength between 400 and 800 nm is 0.1% or more, or the wavelength is 400 to 800 nm.
The integrated transmittance in any wavelength range between 800 nm is 0.1% or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing pad for a semiconductor wafer, a polishing multilayer body for a semiconductor wafer provided with the polishing pad, and a method for polishing a semiconductor wafer. More specifically,
The present invention relates to a polishing pad for a semiconductor wafer through which light can be transmitted without deteriorating polishing performance, a polishing multilayer body for a semiconductor wafer provided with the polishing pad, and a method for polishing a semiconductor wafer using the same.

[0002]

2. Description of the Related Art In the polishing of a semiconductor wafer, the purpose of polishing is achieved, and the polishing end point at which the polishing is completed can be determined on the basis of empirically obtained time. However, there are various materials constituting the surface to be polished, and the polishing times are all different depending on these. Further, it is conceivable that the material constituting the surface to be polished will change in the future. Furthermore,
The same applies to the slurry used for polishing and the polishing apparatus. For this reason, it is very inefficient to obtain all the polishing times from various polishings. On the contrary,
In recent years, for example, JP-A-9-7985 and JP-A-20
As disclosed in JP-A-00-326220 and the like,
Research is progressing on an optical end point detecting device and method using an optical method that can directly measure the state of the surface to be polished. In the optical end point detection apparatus and method, generally,
For example, a window having no polishing ability made of a hard and uniform resin through which light for end point detection can be transmitted as disclosed in Japanese Patent Publication No. 11-512977 or the like is formed on a polishing pad. To be polished is measured.

[0003]

However, in the above-mentioned polishing pad, since the window has no polishing ability, there is a concern that the provision of the window may lower the polishing performance of the polishing pad. In addition, it is difficult to increase the size of the window or to provide the window in a ring shape. The present invention solves the above problems,
In polishing a semiconductor wafer using an optical end point detection apparatus, a polishing pad for a semiconductor wafer capable of transmitting end point detection light without deteriorating polishing performance, a polishing multilayer body for a semiconductor wafer provided with the polishing pad, and a semiconductor An object of the present invention is to provide a method for polishing a wafer.

[0004]

The present inventors have studied a polishing pad for a semiconductor wafer used for polishing using an optical end point detecting device. Even if it is not a polishing pad provided as a, if the matrix material itself has translucency, sufficient translucency can be secured as a window, and furthermore, it is possible to detect the polishing end point using an optical end point detector. I found that.
At the same time, they have found that sufficient translucency can be ensured even when light is scattered due to inclusion of inclusions in the matrix material, and completed the present invention.

[0005] A polishing pad for a semiconductor wafer of the present invention (hereinafter simply referred to as a "polishing pad") comprises a water-insoluble matrix material and water-soluble particles dispersed in the water-insoluble matrix material. It has characteristics.

The above "water-insoluble matrix material" (hereinafter referred to as "matrix material")
The “matrix material” simply has a role of maintaining the shape of the polishing pad and retaining water-soluble particles described below in the polishing pad. As the matrix material, a thermoplastic resin capable of imparting a light-transmitting property, a thermosetting resin,
It is preferable to use an elastomer and a rubber alone or in combination. There is no particular limitation on the method by which the light-transmitting property can be imparted. For example, a material that can have light-transmitting property by controlling the crystallinity or the like can be used. The matrix material does not need to be transparent itself (including translucent) as long as it can be provided with a light-transmitting property (regardless of whether or not visible light is transmitted), but the light-transmitting property is preferably higher. More preferably, it is transparent.

Examples of the thermoplastic resin include polyolefin resin, polystyrene resin, polyacrylic resin (such as (meth) acrylate resin), vinyl ester resin (excluding acrylic resin), polyester resin, and polyamide resin. Resins, fluorine resins, polycarbonate resins, polyacetal resins, and the like can be given. Further, as the thermosetting resin, for example, phenolic resin, epoxy resin, unsaturated polyester resin, polyurethane resin, polyurethane-urea resin and urea resin,
Silicon resin and the like can be mentioned.

Further, as such an elastomer,
Styrene-butadiene-styrene block copolymer (S
BS), styrene-based elastomers such as hydrogenated block copolymers (SEBS), polyolefin elastomers (TPO), thermoplastic polyurethane elastomers (T
PU), thermoplastic polyester elastomer (TPE)
E), a thermoplastic elastomer such as a polyamide elastomer (TPAE), a diene elastomer (eg, 1,2-polybutadiene), a silicone resin elastomer, a fluororesin elastomer, and the like. Examples of the rubber include butadiene rubber, styrene / butadiene rubber, isoprene rubber, isobutylene / isoprene rubber, acrylic rubber, acrylonitrile / butadiene rubber, ethylene / propylene rubber, ethylene / propylene / diene rubber, silicone rubber, and fluoro rubber. Can be mentioned.

These matrix materials include acid anhydride groups,
It may be modified with at least one of a carboxyl group, a hydroxyl group, an epoxy group and an amino group.
By the modification, affinity with water-soluble particles, abrasive grains, an aqueous medium and the like described later can be adjusted. These matrix materials can be used in combination of two or more.

The matrix material is not particularly limited as to whether it is a crosslinked polymer or a non-crosslinked polymer, but at least a part thereof (a mixture of two or more materials,
When at least one part of at least one of them is a crosslinked polymer, and
(Including the case where the part is a crosslinked polymer) is preferably a crosslinked polymer.

When at least a part of the matrix material has a crosslinked structure, the matrix material can be provided with an elastic recovery force. Therefore, displacement due to shear stress applied to the polishing pad during polishing can be suppressed to a small extent, and it is possible to prevent the matrix material from being excessively stretched during polishing and dressing, thereby preventing the pores from being filled by plastic deformation. Also, it is possible to prevent the polishing pad surface from being excessively fluffed. For this reason, the holding property of the slurry during polishing is good,
It is easy to recover the slurry retention by dressing, and it is also possible to prevent the occurrence of scratches.

Among the above-mentioned crosslinked polymers, among the thermoplastic resins, thermosetting resins, elastomers and rubbers capable of imparting the above-mentioned light-transmitting properties, polyurethane resins, epoxy resins, polyacryl resins, unsaturated polyester resins , Vinyl ester resin (excluding polyacrylic resin), diene elastomer (1,2-polybutadiene), butadiene rubber, isoprene rubber, acrylic rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber , Silicone rubber, fluoro rubber, styrene-isoprene rubber, etc., cross-linked polymer, polyethylene, polyvinylidene fluoride, etc. cross-linked (by irradiation with a cross-linking agent, ultraviolet ray or electron beam), etc. Can be. In addition, ionomers and the like can be used.

[0013] Among these crosslinked polymers, they can impart sufficient translucency, are stable to strong acids and strong alkalis contained in many slurries, and have little softening due to water absorption. It is particularly preferable to use the crosslinked 1,2-polybutadiene, and the crosslinked 1,2-polybutadiene can be used by being blended with another rubber such as butadiene rubber or isoprene rubber. Further, 1,2-polybutadiene can be used alone as the matrix material.

In such a matrix material at least a part of which is a crosslinked polymer, according to JISK6251
When a test piece made of a matrix material is fractured at 80 ° C., the elongation remaining after fracture (hereinafter, simply referred to as “residual fracture elongation”) can be reduced to 100% or less. That is, it is a matrix material in which the total distance between the marked lines of the test piece after breaking is not more than twice the distance between the marked lines before breaking. This residual elongation at break is more preferably 30% or less (more preferably 10% or less, particularly preferably 5% or less, and usually 0% or more). As the residual elongation at break increases beyond 100%, the fine pieces scraped or elongated from the polishing pad surface during polishing and surface renewal tend to block the pores.

The residual elongation at break is defined in JIS K62.
In accordance with 51 "Tensile test method for vulcanized rubber", when the test piece was broken in a tensile test at a test piece shape dumbbell-shaped No. 3, a tensile speed of 500 mm / min, and a test temperature of 80 ° C,
It is the elongation obtained by subtracting the distance between the marked lines before the test from the total distance from each marked line to the broken part of the test piece that has been broken and divided. The test temperature was set at about 80 ° C. because the temperature reached by sliding in actual polishing was about 80 ° C.

The above-mentioned "water-soluble particles" are dispersed in a matrix material, dissolved or swelled by contact with an aqueous medium supplied from the outside during polishing, and are separated from the surface of the polishing pad (by dissolution or swelling, etc.). ) Are particles that can form a pore that can hold a slurry at the trace of the detachment and temporarily retain polishing dust. The shape of the water-soluble particles is not particularly limited, but is generally preferably more spherical, and more preferably spherical. Further, it is preferable that each water-soluble particle has a more uniform shape. The properties of the pores formed by this are uniform,
Good polishing can be performed.

Although the size of the water-soluble particles is not particularly limited, it is usually 0.1 to 500 μm (more preferably 0.5 to 100 μm, and still more preferably 1 to 80 μm).
The particle size is preferably If the particle size is less than 0.1 μm, the size of the pores may be smaller than that of the abrasive grains, and it may not be possible to sufficiently hold the abrasive grains in the pores, which is not preferable. On the other hand, if it exceeds 500 μm, the size of the formed pore becomes excessive, and the mechanical strength and polishing rate of the polishing pad tend to decrease.

The water-soluble particles contained in the polishing pad have a total of 100% of the matrix material and the water-soluble particles.
10% to 90% by volume of water-soluble particles
(More preferably 15 to 60% by volume, further preferably 2
(0 to 40% by volume). If the content of the water-soluble particles is less than 10% by volume, a sufficient amount of pores will not be formed, and the polishing rate tends to decrease. On the other hand, if it exceeds 90% by volume, it tends to be difficult to prevent unintentionally dissolving or swelling not only the water-soluble particles exposed on the polishing pad surface but also the water-soluble particles present inside. . Therefore, it is difficult to maintain the hardness and mechanical strength of the polishing pad at appropriate values during polishing.

The water-soluble particles are not particularly limited, and various materials can be used. For example, organic water-soluble particles and inorganic water-soluble particles can be used. Organic water-soluble particles include dextrin, cyclodextrin, mannitol, sugars (such as lactose), celluloses (such as hydroxypropylcellulose and methylcellulose), starch, proteins, polyvinyl alcohol,
Examples thereof include those formed from polyvinylpyrrolidone, polyacrylic acid, polyethylene oxide, a water-soluble photosensitive resin, sulfonated polyisoprene, sulfonated polyisoprene copolymer, and the like. Further, examples of the inorganic water-soluble particles include particles formed from potassium acetate, potassium nitrate, potassium carbonate, potassium hydrogen carbonate, potassium chloride, potassium bromide, potassium phosphate, magnesium nitrate, and the like. These water-soluble particles may contain each of the above materials alone or in combination of two or more. Furthermore, one kind of water-soluble particles made of a predetermined material may be used, or two or more kinds of water-soluble particles made of different materials may be used.

It is preferable that only the water-soluble particles exposed on the surface of the polishing pad are water-soluble, and those present inside the polishing pad without being exposed do not absorb or swell. For this reason, an outer shell made of an epoxy resin, a polyimide, a polyamide, a polysilicate, or the like that suppresses moisture absorption may be formed on at least a part of the outermost part of the water-soluble particles.

The water-soluble particles have a function of increasing the indentation hardness of the polishing pad in the polishing pad in addition to the function of forming pores (for example, Shore D).
Hardness 35-100). Due to the large indentation hardness, the pressure applied to the surface to be polished in the polishing pad can be increased, and not only the polishing rate can be improved, but also high polishing flatness can be obtained. Therefore, it is preferable that the water-soluble particles are solid bodies capable of securing sufficient indentation hardness in the polishing pad.

The method of dispersing the water-soluble particles in the matrix material is not particularly limited, but it can be usually obtained by kneading the matrix material, the water-soluble particles and other additives. In this kneading, the matrix material is heated and kneaded so as to be easily processed. At this temperature, the water-soluble particles are preferably solid. By being solid, it becomes easy to disperse the water-soluble particles in a state of exhibiting the preferred average particle size, regardless of the degree of compatibility with the matrix material. Therefore, it is preferable to select the type of the water-soluble particles depending on the processing temperature of the matrix material to be used.

In the polishing pad of the present invention, the slurry is held by the above-mentioned pores, and the polishing waste can be temporarily retained. The planar shape of the polishing pad is not particularly limited, and may be, for example, a circular shape (a disk shape or the like) or a polygon {a quadrangle or the like (belt shape, roller shape)}. The size is not particularly limited. For example, in the case of a disk shape, the diameter may be 500 to 900 mm.

Although the polishing pad of the present invention does not have to have a thin portion, in general, when light is transmitted through a light-transmitting object, the intensity of the light is the square of the length of the transmitting object. Attenuates in proportion to Therefore, the transmittance can be dramatically improved by reducing the thickness of the transmitting portion. For example, in a polishing pad used for polishing for optically detecting an end point, even if light having sufficient intensity for end point detection is hardly transmitted except for the thinned portion, the end point detection is performed for a thin portion. It is possible to secure sufficient light intensity.

Therefore, it is preferable to have a thin portion.
The thin portion is a portion formed thinner than the maximum thickness of the polishing pad (for example, FIGS. 1 to 4 and the like). The planar shape of the thin portion is not particularly limited, and may be, for example, a circle, a sector (a shape obtained by cutting a circle or a ring at a predetermined angle), a polygon (a square, a rectangle, a trapezoid, or the like), a ring, or the like. Further, the cross-sectional shape of the thin portion can be, for example, a polygon (a quadrangle, a pentagon, or the like), a dome, or another shape (see FIGS. 1 to 4, and the upper side in each drawing is a polished surface). Shall be).

Further, the number of thin portions provided in the polishing pad is not particularly limited, and may be one, or two or more. The arrangement is not particularly limited. For example,
When one thin portion is provided, it can be arranged as shown in FIGS. Further, when two or more thin portions are provided, they may be formed concentrically (FIG. 7) or the like.

Although the thickness of the thin portion is not particularly limited, it is usually preferable that the thinnest portion in the thin portion is 0.1 mm or more (more preferably 0.3 mm or more, usually 3 mm or less). If it is less than 0.1 mm, it tends to be difficult to secure sufficient mechanical strength in this portion. Also, the size of the thin portion is not particularly limited,
For example, in the case of a circular shape, the diameter is preferably 20 mm or more. In the case of a circular shape, the width is preferably 20 mm or more.
mm or more and 10 mm or more in width.

Further, the thin portion may be formed by recessing the surface side of the polishing pad (see FIG. 2).
However, it is preferable that the rear surface side be formed with a concave portion (see FIG. 1). Since the back surface is concavely recessed, good light transmittance can be obtained without affecting polishing performance.

In addition to the concave portion for obtaining the thin portion, the surface (polishing surface) of the polishing pad of the present invention is provided for the purpose of improving the retention of slurry and the discharging of used slurry. If necessary, a predetermined width (for example, 0.1 to 2
mm), a groove can be formed at a depth and an interval, and a dot pattern can be provided. These grooves and dot patterns can be formed in a predetermined shape (for example, concentric shape, lattice shape, spiral shape, radial shape, etc.). In addition, the groove and the dot pattern can be also used by a concave portion which is notched to form the thin portion.

The above-mentioned “light-transmitting property” is not particularly limited as long as it can transmit light. Usually, when the thickness of the polishing pad is 2 mm, the light-transmitting property is any one of wavelengths between 100 and 3000 nm. Preferably, the transmittance is 0.1% or more, or the integrated transmittance in any wavelength range between 100 and 3000 nm is 0.1% or more. The transmittance or the integrated transmittance is preferably 1% or more, more preferably 2% or more. However, the transmittance or the integrated transmittance does not need to be higher than necessary, and may be generally 50% or less.
It may be 0% or less, particularly 20% or less.

Further, in the polishing pad used for polishing using the optical end point detector, it is preferable that the transmittance at 400 to 800 nm, which is a particularly frequently used region as end point detection light, is high. Therefore, when the thickness is 2 mm, the transmittance at any wavelength between 400 and 800 nm is 0.1% or more (more preferably 1% or more, further preferably 2% or more, particularly preferably 3% or more, usually 50% or less) or wavelength 4
0.1% or more (more preferably 1% or more, further preferably 2% or more, particularly preferably 3% or more, usually 5% or more) in any wavelength range between 00 and 800 nm.
0% or less). However, the transmittance or the integrated transmittance does not need to be higher than necessary.
% Or less, further may be 10% or less, and particularly may be 5% or less.

The transmittance is a value obtained by measuring the transmittance at each wavelength using a device such as a UV absorbance meter capable of measuring the absorbance at a predetermined wavelength on a test piece having a thickness of 2 mm. The integrated transmittance can also be obtained by integrating the transmittance in a predetermined wavelength range measured similarly.

Further, in addition to the matrix material and the water-soluble particles, the polishing pad of the present invention further comprises abrasive grains, oxidizing agents, alkali metal hydroxides and acids, pH adjusting agents, At least one of a surfactant, an anti-scratch agent, and the like can be contained in a range that can maintain light-transmitting properties. Thereby, it becomes possible to perform polishing by supplying only water during polishing.

Further, a compatibilizer can be blended to improve the affinity between the matrix material and the water-soluble particles and the dispersibility of the water-soluble particles in the matrix material. Examples of the compatibilizer include polymers modified with acid anhydride groups, carboxyl groups, hydroxyl groups, epoxy groups, oxazoline groups and amino groups, block copolymers, random copolymers, and various nonionics. Surfactants, coupling agents and the like can be mentioned.

Further, the polishing pad of the present invention may contain various additives such as a filler, a softener, an antioxidant, an ultraviolet absorber, an antistatic agent, a lubricant, and a plasticizer, if necessary. it can. Further, a reactive additive such as sulfur or a peroxide may be added to cause a reaction to be crosslinked. In particular, as a filler, a material for improving rigidity such as calcium carbonate, magnesium carbonate, talc, and clay, and a polishing effect of silica, alumina, ceria, zirconia, titania, manganese dioxide, manganese trioxide, barium carbonate, etc. are provided. A material or the like may be used.

The term "slurry" as used in the present specification means an aqueous dispersion containing at least abrasive grains. The slurry may be supplied from the outside during polishing. May be used alone.
When only the aqueous medium is supplied, for example, the slurry is formed by mixing the abrasive particles and the like discharged from the inside of the polishing pad and the aqueous medium in the polishing process.

The polishing multilayer body for a semiconductor wafer of the present invention (hereinafter also simply referred to as “polishing multilayer body”) is laminated on the polishing pad for a semiconductor wafer of the present invention and the back side of the polishing pad for the semiconductor wafer. And a light-transmitting property in the stacking direction.

The "support layer" is a layer laminated on the back surface of the polishing pad opposite to the polishing surface. The planar shape of the support layer is not particularly limited, and may be, for example, a circle, a polygon (a square or the like), etc., and is usually the same planar shape as the polishing pad, and further, is a thin plate. Also,
The number of layers of the support layer is not limited.
It may have more than one layer. Further, when two or more support layers are laminated, each layer may be the same or different.

Although the total thickness of the support layer is not particularly limited, it can usually be 0.1 to 2 times the thickness of the polishing pad. Also, the hardness of the support layer is not particularly limited, but by setting the Shore D hardness to 10 to 80 (more preferably 20 to 50), even when the Shore D hardness of the polishing pad is as high as 60 to 90. At the time of polishing, the polishing multilayer body as a whole has sufficient flexibility and can have appropriate followability to the unevenness of the surface to be polished. This support layer, in order not to impair the translucency of the polishing pad,
It is preferable that the support layer itself also has a light-transmitting property. Therefore,
A part of the support layer may be thinned or cut out, or a member having a light transmitting property may be joined to the cutout.

Since the polishing pad and the polishing multilayer body of the present invention have a light transmitting property, they can be used in a semiconductor wafer polishing apparatus having an optical end point detector. The optical end point detector is an apparatus that transmits light from the back surface side of the polishing pad to the polishing surface side and can detect the polishing end point of the surface to be polished from the light reflected on the surface of the object to be polished. Other measurement principles are not particularly limited.

The method for polishing a semiconductor wafer according to the present invention is a method for polishing a semiconductor wafer using the polishing pad or the polishing multilayer body according to the present invention, wherein the polishing end point of the semiconductor wafer is detected by using an optical end point detector. It is characterized by performing.

The "optical end point detector" is the same as described above. According to the method for polishing a semiconductor wafer of the present invention, polishing can be performed while constantly observing the polishing end point, and polishing can be reliably completed at the optimum polishing end point. As a method for polishing a semiconductor wafer of the present invention, for example, a polishing apparatus as shown in FIG. 8 can be used. That is, a rotatable platen 2, a pressurizing head 3 capable of rotating and moving vertically and horizontally, a slurry supply unit 5 capable of dropping a predetermined amount of slurry per unit time on the platen, This is an apparatus including the installed optical end point detector 6.

In this polishing apparatus, the polishing pad (polishing multilayer body) 1 of the present invention is fixed on a surface plate, while the semiconductor wafer 4 is fixed on the lower end face of a pressure head, and the semiconductor wafer is polished. The pad is brought into contact with the pad while pressing it with a predetermined pressure. Then, while the slurry or water is dropped on the surface plate by a predetermined amount from the slurry supply portion, the surface wafer and the pressure head are rotated to slide the semiconductor wafer and the polishing pad to perform polishing.

At the time of this polishing, light R ₁ for detecting an end point of a predetermined wavelength or wavelength range is supplied from an optical end point detector.
Irradiation is performed from below the platen (the platen itself has a light-transmitting property or a part of the platen is cut out so that light for end point detection can be transmitted) toward the surface to be polished of the semiconductor wafer. Then, capture the reflected light R ₂ reflected by the polished surface of the end-point detection light semiconductor wafer with optical end-point detector, it can be polished while observing the condition of the surface to be polished from this reflected light .

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to examples. [1] 1,2-Polybutadiene (manufactured by JSR Corporation, product name “JSR RB83”), which is crosslinked and becomes a matrix material after the production of the polishing pad
0 ") 80% by volume, and 20% by volume of β-cyclodextrin (Yokohama International Bio-Laboratory Co., Ltd., product name“ Dexy Pearl β-100 ”) as water-soluble particles are kneaded in a kneader heated to 120 ° C. did. Then, 0.2 parts by mass of dicumyl peroxide (manufactured by NOF CORPORATION, product name "Parkmill D") was added, in which the total of 1,2-polybutadiene and β-cyclodextrin was calculated as 100 parts by mass. After further kneading, 1
Cross-linking reaction at 70 ° C for 20 minutes, molding, diameter 60c
Thus, a polishing pad having a thickness of 2 mm and a thickness of 2 mm was obtained.

[2] Measurement of transmittance UV absorbance meter (manufactured by Hitachi, Ltd., model “U-20”)
10 "), the transmittance at a wavelength of 400 to 800 nm was measured at five different points on the polishing pad, and the average value was calculated. As a result, the average integrated transmittance of the five measurements was 7%. In addition, 633 nm (general He-Ne
The transmittance at (laser wavelength) was 6.5%.

[0047]

According to the polishing pad and polishing multilayer body of the present invention and the method for polishing a semiconductor wafer of the present invention, an optical end point can be detected without lowering the polishing performance. Further, according to the polishing pad and the polishing multilayer body of the present invention, not only the polishing end point but also the entire polishing state can be optically observed at all times.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating an example of a cross section of a thin portion of a polishing pad of the present invention.

FIG. 2 is a schematic diagram illustrating an example of a cross section of a thin portion of the polishing pad of the present invention.

FIG. 3 is a schematic view illustrating an example of a cross section of a thin portion of the polishing pad of the present invention.

FIG. 4 is a schematic view illustrating an example of a cross section of a thin portion of the polishing pad of the present invention.

FIG. 5 is a schematic view illustrating an example of a planar shape of a thin portion according to the present invention, as viewed from a rear surface direction.

FIG. 6 is a schematic diagram illustrating an example of a planar shape of a thin portion according to the present invention, as viewed from a back surface direction.

FIG. 7 is a schematic diagram illustrating an example of a planar shape of a thin portion according to the present invention, as viewed from a back surface direction.

FIG. 8 is a schematic diagram illustrating a polishing apparatus using the polishing pad or the polishing multilayer body of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1; Polishing pad (polishing multilayer body), 11; Thin part, 2; Surface plate, 3; Pressure head, 4; Semiconductor wafer, 5; Slurry supply part, 6; Optical end point detector, R ₁ ; Detection light,
R ₂ : reflected light.

Claims (9)

[Claims] 1. A polishing pad for a semiconductor wafer, comprising: a water-insoluble matrix material; and water-soluble particles dispersed in the water-insoluble matrix material, and having translucency. 2. The polishing pad for a semiconductor wafer according to claim 1, wherein at least a part of the water-insoluble matrix material is a crosslinked polymer. 3. The crosslinked polymer of claim 1, wherein the crosslinked polymer is
3. The polishing pad for a semiconductor wafer according to claim 2, wherein the polishing pad is polybutadiene. 4. The polishing pad for a semiconductor wafer according to claim 1, further comprising a thin portion, through which the light for detecting an end point passes. 5. The polishing pad for a semiconductor wafer according to claim 4, wherein the thin portion is formed by recessing a back surface side. 6. When the thickness is 2 mm, a wavelength of 400
2. The transmittance at any wavelength between 800 nm and 800 nm is 0.1% or more, or the integrated transmittance at any wavelength between 400 nm and 800 nm is 0.1% or more. 3. 6. The polishing pad for a semiconductor wafer according to any one of items 1 to 5. 7. A polishing pad for a semiconductor wafer according to any one of claims 1 to 6, and a support layer laminated on the back side of the polishing pad for a semiconductor wafer, wherein the polishing pad is transparent in the laminating direction. A polishing multilayer body for a semiconductor wafer, which has optical properties. 8. The polishing pad for a semiconductor wafer according to claim 1, wherein the polishing pad is used for a semiconductor wafer polishing apparatus provided with an optical end point detector. body. 9. A method for polishing a semiconductor wafer using the polishing pad for a semiconductor wafer according to any one of claims 1 to 6 or the polishing multilayer body for a semiconductor wafer according to claim 7. A method for polishing a semiconductor wafer, wherein the detection of the polishing end point of the semiconductor wafer is performed using an optical end point detector.