JP2002198335A - Polishing pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor wafer polishing pad for a polishing process of flattening micro unevenness of a fine pattern formed on a semiconductor wafer, which meets a need for incompatible properties of uniformity of an amount of polishing on the whole surface of the wafer and of unevenness- flattening on a minute region, and causes few scratches. SOLUTION: In the polishing pad used for polishing the semiconductor wafer, a polishing layer of the pad is of a porous urethane and mixed with hollow resin particles to make the layer porous, and a polishing surface-active agent of 0.05 wt.%-1 wt.% is added to the urethane resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method for flattening a semiconductor substrate, and more particularly, to a method for forming a fine pattern on a semiconductor wafer and flattening fine irregularities on the pattern. The present invention relates to a polishing pad used in a polishing process.

[0002]

2. Description of the Related Art Generally, a semiconductor wafer is subjected to a so-called chemical mechanical polishing method in a finishing process or a multi-layer wiring process for device fabrication.
According to g), mirror polishing and planarization of an interlayer insulating film and a conductive film are performed. In such polishing, characteristics such as uniformity of the amount of polishing over the entire surface of the wafer, selective polishing of the convex portions of the uneven steps, and flatness of the uneven portions after polishing are required. The following polishing pads have been developed and studied to meet these requirements, but each has its own problems.

[0003] For example, US Pat. No. 3,504,457 discloses a polishing pad in which a synthetic leather layer as a polishing layer is laminated on an elastic polyurethane layer. Plays a role in equalizing the load applied to the wafer,
Since soft synthetic leather is used for the outermost polishing layer, there is no problem such as scratching, but there is a problem that flattening characteristics in a minute area are not good.

Japanese Patent Application Laid-Open No. Hei 6-21028 discloses a polishing pad having a structure in which a polyurethane impregnated nonwoven fabric is bonded to a foamed polyurethane layer. However, even when a polyurethane and a nonwoven fabric are laminated, the nonwoven fabric layer is equivalent to the above-mentioned elastic polyurethane layer. And achieve uniformity. In addition, since the polishing layer also has a hard foamed polyurethane layer, it has excellent flattening characteristics as compared with synthetic leather. In polishing, the required level has not been reached. Further, the flattening characteristics can be improved by further increasing the hardness of the hard urethane layer. However, in this case, scratches occur frequently, which is not practical.

JP-A-6-77185 provides a polishing surface and a rigid element of selected thickness and rigidity adjacent to the polishing surface, wherein the rigid element has a substantially uniform surface. An elastic element is provided adjacent to the rigid element for applying a force, the rigid element and the elastic element applying an elastic bending force to the polishing surface to induce a controlled bending on the polishing surface. A polishing pad is disclosed that conforms to the overall shape of the workpiece surface and maintains a controlled stiffness with respect to the local shape of the workpiece surface. Layer, rigid layer,
The elastic layer has a structure in which the surface polishing layer has an appropriate hardness that does not cause scratching, and the second rigid layer improves the flattening characteristics that are not increased and deteriorated. This solves the problem of the method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 6-21028. In this case, the thickness of the polishing layer is specified to be 0.003 inches or less. In this case, there is a disadvantage that the polishing layer is also shaved and the product life is short.

[0006] in JP-A 10-156724 has a great surface A of the longitudinal elastic modulus E _A, and a small lower layer B modulus of longitudinal elasticity E _B, both layers A, than the B layer between the B A polishing cloth characterized by providing at least an intermediate layer M having a large longitudinal modulus of elasticity is disclosed, but the basic idea of this method is the same as the method of JP-A-6-77185 described above. Attempts have been made to obtain a more efficient range by limiting the rate range, but there is practically no means of realizing this method, and it is difficult to produce a polishing pad.

Japanese Patent Application Laid-Open No. 11-48131 discloses a polishing layer,
A pad in which the intermediate layer is divided by an intermediate layer having a higher elasticity than the polishing layer and a soft underlayer is disclosed. However, even in this method, the basic idea is disclosed in Japanese Patent Application Laid-Open No. 6-771.
Same as 85, except that the intermediate rigid layer is divided into a predetermined size in order to further improve the uniformity in the wafer plane. However, this dividing step is costly, and an inexpensive polishing pad cannot be supplied.

As described above, at present, a sufficiently satisfactory polishing pad has not been obtained.

[0009]

In the present invention, the urethane resin is made porous in order to improve the polishing rate of the polishing pad. Conventionally, in order to make the porous material porous, bubbles have been taken in by a stirring blade and mechanically foamed. However, it is difficult to obtain a minute and stable foaming state.
Therefore, in the present invention, a stable foaming state is obtained by mixing hollow resin fine particles. As a polishing pad having such a configuration, Japanese Patent No. 3013105 proposes a polishing pad including a polymer microelement. With the manufacturing method described here, fine elements cannot be mixed well,
It takes a long time to stir well without taking in bubbles. In addition, when the semiconductor was polished with the obtained pad, the semiconductor was easily scratched, and had many problems.

Therefore, the present inventors have found that when mixing a prepolymer and hollow microparticles, a surfactant is added in a range of 0.05 wt% to 1 wt% to disperse the particles very well. .

Further, the present inventors have added that, in addition to the above, the addition of a surfactant allows the hollow particles to be rapidly dispersed without agglomeration, so that scratches derived from the aggregates of the particles are less likely to occur. I found it.

The present invention has been completed based on the above findings and further studies.

[0013]

That is, the present invention relates to a semiconductor wafer polishing pad having a polishing layer containing hollow resin particles, wherein the polishing layer contains 0.05 wt% to 1 wt% of a surfactant. And a semiconductor wafer polishing pad.

In a preferred embodiment of the semiconductor wafer polishing pad of the present invention, the surfactant is a silicone-based surfactant.

In a preferred embodiment of the semiconductor wafer polishing pad of the present invention, the silicone-based surfactant mainly comprises a copolymer of silicone and polyether.

In a preferred embodiment of the semiconductor wafer polishing pad of the present invention, when the hardness of the polished surface of the polishing layer is measured by a D-type rubber hardness meter, the hardness is 45 to 65.

In a preferred embodiment of the semiconductor wafer polishing pad according to the present invention, the polishing rate of the polishing layer is 0.5% to 10%.
%.

In a preferred embodiment of the semiconductor wafer polishing pad of the present invention, the polishing layer has a density of 0.5 to 1.2.

In a preferred embodiment of the semiconductor wafer polishing pad of the present invention, the polishing pad comprises at least two layers, and at least one layer other than the polishing layer comprises a material having a lower elastic modulus than the polishing layer.

In a preferred embodiment of the semiconductor wafer polishing pad of the present invention, the material having a low elastic modulus is made of a material selected from a urethane-impregnated polyester nonwoven fabric, a polyurethane foam, and a polyethylene foam.

In a preferred embodiment of the semiconductor wafer polishing pad of the present invention, the respective layers are bonded by a double-sided tape.

In a preferred embodiment of the semiconductor wafer polishing pad of the present invention, the peel strength between the layers formed by laminating the double-sided tape is 300 g / cm or more.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The polishing layer constituting the semiconductor wafer polishing pad of the present invention contains 0.05 to 1 wt% of a surfactant. When the amount of the surfactant is less than 0.05 wt%, the dispersibility of the hollow resin particles is significantly deteriorated. As a result, it takes a long time to complete the dispersion, and the productivity deteriorates. During the stirring, air dissolves in the prepolymer, which appears as bubbles in the pad during the curing reaction, resulting in a pad with many cavities. , Agglomerates (clusters) of particles in the pad increase, scratches on the polished semiconductor (scratch)
May be a problem. When the amount of the surfactant exceeds 1% by weight, bubbles entrained at the time of stirring become difficult to disappear, large cavities derived from the bubbles increase, and the polishing rate decreases or becomes unstable.

The surfactant used in the semiconductor wafer polishing pad of the present invention is preferably a silicone-based surfactant, and more preferably a surfactant of a copolymer of silicone and polyether.

The silicone is not particularly limited, but, for example, the following chemicals 1 to 6 are preferably used.

[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031]

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The polyether is not particularly limited, but may be, for example, polyethylene oxide,
Polypropylene oxide or a copolymer thereof is preferably used.

The polyurethane resin used for the polishing layer constituting the semiconductor wafer polishing pad of the present invention comprises an isocyanate-terminated urethane prepolymer and an organic diamine compound.

The above isocyanate-terminated urethane prepolymer comprises a polyisocyanate, a high molecular polyol and a low molecular polyol.

Examples of the polyisocyanate include 2,4- and / or 2,6-diisocyanatotoluene, 2,2'-, 2,4'- and / or 4,4'-
Diisocyanatodiphenylmethane, 1,5-naphthalene diisocyanate, p- and m-phenylene diisocyanate, dimeryl diisocyanate, xylylene diisocyanate, diphenyl-4,4'- Diisocine
1,3- and 1,4-tetramethylxylidene diisocyanate, tetramethylene diisocyanate,
6-hexamethylene diisocyanate, dodecamethylene diisocyanate, cyclohexane-1,3- and 1,4
Diisocyanate, 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane (=
Isophorone diisocyanate), bis- (4-isocyanatocyclohexyl) methane (= hydrogenated MDI), 2- and 4-isocyanatocyclohexyl-2'-isocyanatocyclohexylmethane, 1,3- and 1,4-bis-
(Isocyanatomethyl) -cyclohexane, bis- (4
-Isocyanato-3-methylcyclohexyl) methane,
And the like.

Examples of the above-mentioned high molecular polyol include hydroxy-terminated polyesters, polycarbonates, polyester carbonates, polyethers, polyether carbonates.
Among them, polyether and polycarbonate having good hydrolysis resistance are preferable, and polyether is particularly preferable from the viewpoint of price and melt viscosity. As the polyether polyol, a reaction product of a starting compound having a reactive hydrogen atom with an alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran, epichlorohydrin or a mixture of these alkylene oxides Is mentioned. Starting compounds having a reactive hydrogen atom include water, bisphenol A and the divalent alcohols described above for producing polyester polyols.

Polycarbonate having a hydroxy group
For example, 1,3-propanediol, 1,
Diols such as 4-butanediol, 1,6-hexanediol, diethylene glycol, polyethylene glycol, polypropylene glycol and / or polytetramethylene glycol and phosgene, diallyl carbonate (E.g., diphenyl carbonate) or a reaction product with a cyclic carbonate (e.g., propylene carbonate). Examples of the polyester polyol include a reaction product of a divalent alcohol and a dibasic carboxylic acid.In order to improve hydrolysis resistance, a longer distance between ester bonds is preferable. Combinations of long chain components are desirable. The divalent alcohol is not particularly limited, but for example, ethylene glycol, 1,3- and 1,2-propylene glycol, 1,4- and 1,3-
And 2,3-butylene glycol, 1,6-hexane glycol, 1,8-octanediol, neopentyl glycol, cyclohexanedimethanol, 1,4-bis- (hydroxymethyl)- Cyclohexane, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentaneddiol, diethylene glycol, dipropylene glycol , Triethylene glycol, tripropylene glycol, dibutylene glycol and the like.

As the dibasic carboxylic acid, there are aliphatic, alicyclic, aromatic and / or heterocyclic ones. From the viewpoint that the resulting terminal NCO prepolymer is required to have a liquid or low melt viscosity, Aliphatic or alicyclic ones are preferable, and when an aromatic type is used, it is preferable to use them together with aliphatic or alicyclic ones. Examples of these carboxylic acids include, but are not limited to, succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid (o-, m-, p-), dimer-fatty acids, such as oleic acid. These polyester polyols may have a part of a carboxyl terminal group. For example, a lactone such as ε-caprolactone or a polyester of a hydroxycarboxylic acid such as ε-hydroxycaproic acid can be used.

Examples of the low-molecular-weight polyol include divalent alcohols used for producing the above-mentioned polyester polyols. The low-molecular-weight polyol of the present invention includes diethylene glycol, 1,3- Butylene glycol, 3-methyl-1,5-pentanediol and 1,6-
It is preferable to use any one of hexamethylene glycol or a mixture thereof. If ethylene glycol or 1,4-butylene glycol, which is a low molecular polyol other than the present invention, is used, the reactivity at the time of casting becomes too fast or the hardness of the finally obtained polyurethane abrasive molding becomes high. Because too much, as the abrasive of the present invention,
It becomes brittle and the IC surface is easily damaged. On the other hand,
When a dihydric alcohol having a longer chain than 1,6-hexamethylene glycol is used, the reactivity at the time of casting and the hardness of the polyurethane abrasive molded product finally obtained may be appropriate. However, it is too expensive and impractical.

The isocyanate component is appropriately selected according to the pot life required at the time of casting, and the terminal NCO prepolymer to be formed must have a low melt viscosity. The above mixture is applied.

Specific examples thereof include, but are not limited to, 2,4- and / or 2,6-diisocyanatotoluene, 2,2'-, 2,4'- and / or 4,4 '.
-Diisocyanatodiphenylmethane, 1,5-naphthalenediisocyanate, p- and m-phenylenediisocyanate, dimeryl diisocyanate, xylylene diisocyanate, diphenyl-4,4 ' -Diisocine-
1,3- and 1,4-tetramethylxylidene diisocyanate, tetramethylene diisocyanate,
6-hexamethylene diisocyanate, dodecamethylene diisocyanate, cyclohexane-1,3- and 1,4
Diisocyanate, 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane (=
Isophorone diisocyanate), bis- (4-isocyanatocyclohexyl) methane (= hydrogenated MDI), 2- and 4-isocyanatocyclohexyl-2'-isocyanatocyclohexylmethane, 1,3- and 1,4-bis-
(Isocyanatomethyl) -cyclohexane, bis- (4
-Isocyanato-3-methylcyclohexyl) methane,
And the like. The organic diamine compound used in the present invention is not particularly limited. For example, 3,3′-dichloro-4,4′-diaminodiphenylmethane, chloroaniline-modified dichlorodiaminodiphenylmethane, 1,2-
Bis (2-aminophenylthio) ethane, trimethylene glycol di-p-aminobenzoate, 3,5-bis (methylthio) -2,6-toluenediamine and the like can be mentioned.

In the present invention, it is essential that the polishing layer contains hollow resin particles for the purpose of stabilizing the polishing rate. The resin particles used in the present invention may be any particles as long as they are hollow, but preferably have a particle diameter of 5 μm or more and 200 μm or less, and particularly preferably 10 μm or more.
00 μm or less is good. Further, the resin constituting the resin particles used in the present invention is not particularly limited,
As an example, an acrylic resin, a vinyl chloride resin, a polyester resin, a vinylidene chloride resin, or a copolymer thereof is exemplified.

When such hollow particles are mixed, the particles are likely to rise because the specific gravity of the particles is small, and it is also preferable that the particles are wetted with a surfactant in advance and charged.

In the present invention, the hardness of the polishing pad polishing layer containing a surfactant is measured by a D-type rubber hardness tester.
It is preferably 5 or more and less than 65. When the D hardness is less than 45, the flattening characteristics deteriorate. When the D hardness is 65 or more, the flatness characteristics are good, but the uniformity deteriorates. Further, in the present invention, the compression rate of the polishing pad is 0.5% or more and 10% or more.
The following is preferred. When the compression ratio is in this range, a polishing pad having excellent uniformity can be obtained.

The compression ratio referred to in the present invention is expressed by equation (7). Compressibility (%) = (T1−T2) / T1 × 100 Equation 7 where T1 = 30 kPa (300 g / c from the no-load state)
m ²⁾ represents the thickness of the sheet when the load was held for 60 seconds stress, show the thickness of the sheet when held 60 seconds the load of T2 = T1 from the state of 180kPa stress.

In the present invention, the density of the multi-hard urethane used for the polishing pad is preferably 0.5 or more and 1.2 or less.
Since the urethane contains hollow resin particles, it is possible to reduce the density, but when the density is 0.5 or less,
Its strength is remarkably reduced and it cannot withstand abrasive friction. Also,
If the density exceeds 1.2, it cannot be realized unless hollow resin particles are almost contained. In this case, there is a problem that the polishing rate when the polishing pad is formed is reduced.

In the present invention, in order to improve the polishing uniformity of the object to be polished, a semiconductor wafer polishing pad having a structure in which a material having a lower elastic modulus than the multi-hard resin urethane layer may be laminated. . In this case, the material layer having a low elastic modulus may be a fibrous nonwoven fabric layer such as a polyester nonwoven fabric, a nylon nonwoven fabric, or an acrylic nonwoven fabric, or a structure in which the nonwoven fabric is impregnated with a urethane resin, or a urethane resin, a polyethylene resin, or the like. Can be used. Among them, urethane-impregnated polyester nonwoven fabric, polyurethane foam, or polyethylene foam is preferable in terms of ease of production, low cost, and stability of physical properties. Particularly preferred is a polyethylene closed-cell foam. By using the foam, an inexpensive pad having excellent repeated load durability can be supplied.

In the present invention, it is preferable to use a double-sided tape as a method of laminating a multi-hard urethane resin polishing layer and a laminated layer having a low elastic modulus subsequent thereto. The double-sided tape used is not particularly limited, but the adhesive strength of the tape in each layer has a peel strength of 300 when measured with a tensile tester at 180 ° peeling with a measuring width of 25 mm.
It is preferably at least g / cm. If the adhesive strength is less than this, there is a risk that the respective layers will peel off between the laminations during polishing.

[0049]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to the examples.

Example 1 A polyether-based urethane prepolymer (Adiprene L-32 manufactured by Uniroyal Co., Ltd.) was placed in a container.
5), 3000 parts by weight, 19 parts by weight of surfactant (dimethylpolysiloxane / polyoxyalkyl copolymer SH192, manufactured by Toray Dow Corning Silicone Co., Ltd.) and 90 parts by weight of hollow resin particles (Expancel 551DE) Parts, and stirred with a stirrer at about 400 rpm to form a mixed solution. Then, the stirrer is replaced and a curing agent (4,4'-methylene-bis [2-chloroaniline]) is charged while stirring 770 parts by weight. .
After stirring for about 1 minute, the mixed solution was poured into a pan-shaped open mold, and post-cured in an oven at 110 ° C. for 6 hours to produce a foamed polyurethane block. The obtained foamed polyurethane has a D hardness of 50, a compressibility of 1.2%, and a specific gravity of 0.
75, and the average bubble diameter was 35 μm. In addition, elemental analysis was performed by X-ray fluorescence, and Si was detected, and it was confirmed that a predetermined surfactant was contained.

Next, this foamed polyurethane block is
Slicer while heating to 50 ° C (Amitec VGW-
At 125), the sheet was sliced to a thickness of 1.27 mm to obtain an abrasive sheet.
Double-sided tape (Sekisui Chemical Co., Ltd.)
Double tack tape # 5673FW) was attached to complete the polishing pad. The adhesive strength of each layer bonded with the double-sided tape was 600 g / cm or more. FIG. 1 shows a schematic configuration diagram of the obtained polishing pad.

The polishing characteristics of the obtained polishing pad were evaluated by a CMP polishing apparatus (SPP-600S manufactured by Okamoto Machine Tool Co., Ltd.) using a silicon wafer on which an oxide film was deposited. At this time, as a slurry, a silica slurry (RD97001 manufactured by Fujimi Incorporated) adjusted to pH 11 was flowed at a flow rate of 150 g / min, and a polishing load of 350 g / cm ² , a polishing pad rotation speed of 35 rpm, and a wafer rotation speed of 33 rpm were used. A polishing experiment was performed. The wafer used for evaluation was a 6-inch silicon wafer on which a thermal oxide film was deposited at 1 μm, and the average polishing rate when polishing was performed at 0.5 μm was determined. At this time, 28 points in each plane of the wafer were measured, and the uniformity in the plane of the wafer was evaluated. Wafer uniformity

Uniformity = (maximum film thickness−minimum film thickness) / (2 × average film thickness) × 100. In the evaluation of the flattening characteristics, a thermal oxide film was deposited on a 6-inch silicon wafer by 0.5 μm, a predetermined patterning was performed, and then an oxide film was deposited by 1 μm by p-TEOS, and a pattern with an initial step difference of 0.5 μm A wafer with a hole was manufactured, and the wafer was polished under the above-mentioned conditions. After polishing, each step was measured to evaluate the flattening characteristics. Two steps were evaluated as the flattening characteristics. One is a local step, which is a step in a pattern in which lines of 500 μm width are arranged in a space of 50 μm, and the other is the amount of shaving at the bottom of the space in 100 μm equally-spaced lines and spaces. Examined.

Table 1 shows the characteristics obtained in this example. It was found that the polishing rate was high and stable, the uniformity was as good as 10% or less, and the flattening characteristics were extremely excellent. .

As a measurement of rubber height, JIS K 6253-1997
Using a compliant D-type rubber altimeter, make the urethane resin foam manufactured to a thickness of 5 mm or more and insert the needle of the hardness meter.
The value after a lapse of 1 minute was defined as hardness.

The adhesive strength was measured by peeling a part of each of the laminated layers formed into a strip cut into a width of 25 mm, and peeling it at 180 ° while pulling at 50 mm / min using a tensile tester, and measuring the strength. did.

The compressibility was determined by applying a load to the produced urethane resin sheet at 25 ° C. with a TMA manufactured by Mac Science Co., Ltd. using a cylindrical indenter having a diameter of 5 mm.
Was measured. Compression rate (%) = (T1−T2) / T1 × 100 where T1 = 30 kPa (300 g / c
m ²⁾ represents the thickness of the sheet when the load was held for 60 seconds stress, show the thickness of the sheet when held 60 seconds the load of T2 = T1 from the state of 180kPa stress.

Example 2 The amount of the surfactant in Example 1 was changed to 30.
The polishing pad was manufactured in the same manner as in Example 1 except that the parts were changed to parts by weight. The resulting foamed polyurethane has a D hardness of 4
7. The compression ratio was 1.4%, the specific gravity was 0.74, and the average bubble diameter was 35 μm. In addition, elemental analysis was performed by X-ray fluorescence, and Si was detected, and it was confirmed that a predetermined surfactant was contained.

As a result, the characteristics are shown in Table 1. It was found that the polishing rate was high and stable, the uniformity was as good as 10% or less, and the flattening characteristics were extremely excellent.

(Example 3) A double-sided tape (double tack tape # 5782 manufactured by Sekisui Chemical Co., Ltd.) was adhered to the polishing sheet obtained in Example 1, and the following layer was laminated as a layer having a low elastic modulus. 3.5 for the lower soft layer
200g / m per unit weight using denier polyester fiber
² of the nonwoven fabric, 30 wt aqueous dispersion polyurethane emulsion
% Impregnated and dried. This nonwoven fabric layer had a compression ratio of about 15%. This non-woven fabric is bonded using the previously manufactured polishing layer and the double-sided tape pasted,
Further, a double-sided tape (double tack tape # 5673FW manufactured by Sekisui Chemical Co., Ltd.) was attached to the nonwoven fabric to complete a polishing pad. The adhesive strength of each layer bonded with the double-sided tape was 600 g / cm or more.

As a result, the characteristics are shown in Table 1. It was found that the polishing rate was high and stable, the uniformity was good at 5% or less, and the flattening characteristics were extremely excellent.

(Example 4) A double-sided tape (double tack tape # 5782 manufactured by Sekisui Chemical Co., Ltd.) was adhered to the polishing sheet obtained in Example 2, and the following layer was laminated as a layer having a low elastic modulus. 3.5 for the lower soft layer
200g / m per unit weight using denier polyester fiber
² of the nonwoven fabric, 30 wt aqueous dispersion polyurethane emulsion
% Impregnated and dried. This nonwoven fabric layer had a compression ratio of about 15%. This non-woven fabric is bonded using the previously manufactured polishing layer and the double-sided tape pasted,
Further, a double-sided tape (double tack tape # 5673FW manufactured by Sekisui Chemical Co., Ltd.) was bonded to the nonwoven fabric to complete a polishing pad. The adhesive strength of each layer bonded with the double-sided tape was 600 g / cm or more.

As a result, although the characteristics are shown in Table 1, it was found that the polishing rate was high and stable, the uniformity was good at 5% or less, and the flattening characteristics were extremely excellent.

Comparative Example 1 The amount of the surfactant in Example 1 was changed to 1.
The polishing pad was manufactured in the same manner as in Example 1 except that the amount was changed to 4 parts by weight. In the foamed polyurethane obtained, the mixed hollow resin particles were agglomerated everywhere. Also, its physical properties
The D hardness was 50, the compression ratio was 1.4%, the specific gravity was 0.74, and the average bubble diameter was 35 μm.

As a result, as shown in Table 1, the polishing rate was unstable and greatly changed every measurement.

(Comparative Example 2) The amount of the surfactant in Example 1 was changed to 10
The polishing pad was manufactured in the same manner as in Example 1 except that the amount was changed to 0 parts by weight. In this case, large bubbles were generated during stirring. In the obtained urethane foam, very large bubbles were observed in addition to the hollow resin particles. Its physical properties are 45 in D hardness, 2.3% compression ratio and 0.70 specific gravity.
It was 5 μm.

The results are shown in Table 1. Although the uniformity was good at 10% or less, the polishing rate was unstable and the flattening characteristics were slightly deteriorated.

Comparative Example 3 The amount of the surfactant in Example 1 was changed to 15
The polishing pad was manufactured in the same manner as in Example 1 except that the amount was changed to 0 parts by weight and the amount of the hollow resin particles was changed to 150 parts by weight. In this case, large bubbles were generated during stirring. In the obtained urethane foam, very large bubbles were observed in addition to the hollow resin particles. In addition, its physical property is 3 in D hardness.
5. The compression ratio was 3.3%, the specific gravity was 0.45, and the average bubble diameter was 60 μm.

The results are shown in Table 1. Although the uniformity was good at 10% or less, the polishing rate was unstable and the flattening characteristics were significantly deteriorated.

Comparative Example 4 The amount of the surfactant in Example 1 was changed to 1.
A polishing pad was manufactured in the same manner as in Example 1 except that the amount was changed to 4 parts by weight and the amount of the hollow resin particles was changed to 40 parts by weight. The resulting urethane foam has reduced air bubbles,
The D hardness was 60, the compression ratio was 0.8%, the specific gravity was 1.25, and the average bubble diameter was 35 μm. The results are shown in Table 1. Although the flattening characteristics were excellent, there were many scratches, the uniformity was deteriorated to 10% or more, and the polishing rate was slightly lowered.

[0071]

[Table 1]

[0072]

According to the present invention, a fine pattern is formed on a semiconductor wafer, and a polishing pad used in a polishing step for flattening fine irregularities of the pattern has a uniform polishing amount over the entire surface of the wafer. The present invention provides a semiconductor wafer polishing pad that meets the conflicting requirements of flatness of unevenness in a minute area and that generates less scratches.

[Procedure amendment]

[Submission date] March 16, 2001 (2001.3.1.
6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Change

[Correction contents]

Next, this foamed polyurethane block is
Slicer while heating to 50 ° C (Amitec VGW-
At 125), the sheet was sliced to a thickness of 1.27 mm to obtain an abrasive sheet.
Double-sided tape (Sekisui Chemical Co., Ltd.)
Double tack tape) was attached to complete the polishing pad. Adhesive strength of each layer bonded with double-sided tape is 60
It was 0 g / cm or more.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0052

[Correction method] Change

[Correction contents]

The polishing characteristics of the obtained polishing pad were evaluated by a CMP polishing apparatus (SPP-600S manufactured by Okamoto Machine Tool Co., Ltd.) using a silicon wafer on which an oxide film was deposited. At this time, the slurry was polished at a polishing load of 350 g / cm2, a polishing pad rotation speed of 35 rpm, and a wafer rotation speed of 33 rpm while flowing a silica slurry (RD97001 manufactured by Fujimi Incorporated) at a flow rate of 150 g / min as a slurry. An experiment was performed. The wafer used for evaluation was a 6-inch silicon wafer on which a thermal oxide film was deposited at 1 μm, and the average polishing rate when polishing was performed at 0.5 μm was determined. At this time, 28 points in each plane of the wafer were measured, and the uniformity in the plane of the wafer was evaluated. The wafer uniformity was calculated by the following equation. Uniformity = (maximum thickness-minimum thickness) / (2 x average thickness) x 10
0

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0053

[Correction method] Change

[Correction contents]

In the evaluation of the flattening characteristics, after a thermal oxide film was deposited on a 6-inch silicon wafer by 0.5 μm, a predetermined patterning was performed, and then an oxide film was deposited by 1 μm by p-TEOS, and an initial step was formed. A wafer having a pattern of μm was manufactured, and the wafer was polished under the above-mentioned conditions. After polishing, each step was measured to evaluate the flattening characteristics. Two steps were evaluated as the flattening characteristics. One is a local step, which is a step in a pattern in which lines of 500 μm width are arranged in a space of 50 μm, and the other is the amount of shaving at the bottom of the space in 100 μm equally-spaced lines and spaces. Examined.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0060

[Correction method] Change

[Correction contents]

(Example 3) A double-sided tape (double tack tape # 5782 manufactured by Sekisui Chemical Co., Ltd.) was adhered to the polishing sheet obtained in Example 1, and the following layer was laminated as a layer having a low elastic modulus. 3.5 for the lower soft layer
200g / m per unit weight using denier polyester fiber
Water-dispersed polyurethane emulsion 30 wt.
% Impregnated and dried. This nonwoven fabric layer had a compression ratio of about 15%. This non-woven fabric is bonded using the previously manufactured polishing layer and the double-sided tape pasted,
Further, a double-sided tape was stuck to the non-woven fabric to complete a polishing pad. The adhesive strength of each layer bonded with the double-sided tape was 600 g / cm or more.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0062

[Correction method] Change

[Correction contents]

(Example 4) A double-sided tape (double tack tape # 5782 manufactured by Sekisui Chemical Co., Ltd.) was adhered to the polishing sheet obtained in Example 2, and the following layer was laminated as a layer having a low elastic modulus. 3.5 for the lower soft layer
200g / m per unit weight using denier polyester fiber
Water-dispersed polyurethane emulsion 30 wt.
% Impregnated and dried. This nonwoven fabric layer had a compression ratio of about 15%. This non-woven fabric is bonded using the previously manufactured polishing layer and the double-sided tape pasted,
Further, a double-sided tape was stuck to the non-woven fabric to complete a polishing pad. The adhesive strength of each layer bonded with the double-sided tape was 600 g / cm or more.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // (C08L 75/04 (C08L 75/04 101: 00 101: 00 83:00) 83:00) ( 72) Inventor Shigeru Komai 2-1-1 Katata, Otsu City, Shiga Prefecture Inside Toyobo Co., Ltd.Research Laboratory (72) Inventor Hiroshi Seyanagi 1-17-18 Edobori, Nishi-ku, Osaka-shi, Osaka Toyo Tire & Rubber Co., Ltd. (72) Inventor Kazuyuki Ogawa 1-17-18 Edobori, Nishi-ku, Osaka-shi, Osaka F-term in Toyo Tire & Rubber Co., Ltd. 4J002 AA00X BD01X BD03X BG00X CF21X CK021 CK041 CP03Y CP18Y FA10X FD31Y GT00

Claims (10)

[Claims] 1. A semiconductor wafer polishing pad having a polishing layer containing hollow resin particles, wherein the polishing layer has a thickness of 0.05%.
A polishing pad for a semiconductor wafer, comprising a wt% to 1 wt% surfactant. 2. The semiconductor wafer polishing pad according to claim 1, wherein the surfactant is a silicone-based surfactant. 3. The semiconductor wafer polishing pad according to claim 2, wherein the silicone-based surfactant mainly comprises a copolymer of silicone and polyether. 4. The semiconductor wafer polishing pad according to claim 1, wherein when the hardness of the polishing surface of the polishing layer is measured by a D-type rubber hardness meter, the hardness is 45 to 65. . 5. The polishing layer has a compression ratio of 0.5% to 10%.
%. The polishing pad for semiconductor wafer according to claim 1, wherein 6. The semiconductor wafer polishing pad according to claim 1, wherein the density of the polishing layer is 0.5 to 1.2. 7. The polishing pad according to claim 1, wherein the polishing pad comprises at least two layers, and at least one layer other than the polishing layer comprises a material having a lower elastic modulus than the polishing layer. Semiconductor wafer polishing pad. 8. The semiconductor wafer polishing pad according to claim 7, wherein the material having a low elastic modulus is made of a material selected from a urethane-impregnated polyester nonwoven fabric, a polyurethane foam, and a polyethylene foam. 9. The pad for polishing a semiconductor wafer according to claim 7, wherein each of the layers is bonded by a double-sided tape. 10. The semiconductor wafer polishing pad according to claim 9, wherein the peel strength between the respective layers formed by laminating the double-sided tape is 300 g / cm or more.