JP2003324087A - Polishing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor wafer polishing pad corresponding to a slurryless state and being capable of reducing occurrence of scratches and eliminating aggregation of grinding particles in the pad and holding the intra- surface uniformity of polishing rates of a polishing target at an extremely excellent state to use the polishing pad for a polishing process for flattening the fine ruggedness of fine patterns formed on a semiconductor wafer. <P>SOLUTION: A resin base material is coated with a polishing material in which fine grinding particles are scattered in resin containing ionic groups in a range of 20 to 1500 eq/ton and the resin base material consists of resin whose Shore A hardness is ≤75. <P>COPYRIGHT: (C)2004,JPO

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 in particular, a fine pattern is formed on a semiconductor wafer and fine irregularities of the pattern are flattened. The present invention relates to a polishing pad used in the polishing process.

[0002]

2. Description of the Related Art Generally, a semiconductor wafer is subjected to a so-called chemical mechanical polishing method (Chemical Mechanical Polishing) in a finishing process step or a multi-layer wiring process in device formation.
mirror polishing and flattening of the interlayer insulating film and the conductive film are performed by means of the nickel polishing. Such polishing requires properties such as uniformity of the polishing amount on the entire surface of the wafer, selective polishing of the convex portions of the uneven steps, and flatness of the concave and convex portions after polishing. In response to these requirements, as a polishing pad, those having the following constitution have been conventionally developed and studied.

A synthetic leather layer as a polishing layer laminated on an elastic polyurethane layer (US Pat. No. 3,504,4)
57)

A structure in which a polyurethane-impregnated non-woven fabric is bonded to a polyurethane foam layer (Japanese Patent Laid-Open No. 6-2102).
(Gazette No. 8)

A polishing surface is provided, and a rigid element of a selected thickness and rigidity is provided adjacent the polishing surface, the rigid element for imparting a substantially uniform force to the rigid element. An elastic element is provided adjacent to the element, the rigid element and the elastic element imparting an elastic bending force to the polishing surface to induce a controlled bending of the polishing surface, which causes the workpiece to A polishing pad adapted to the general shape of a surface and maintaining a controlled stiffness with respect to the local shape of the workpiece surface. (Japanese Patent Laid-Open No. 06-077185)

An intermediate layer having a surface layer A having a large longitudinal elastic modulus E _A and a lower layer B having a small longitudinal elastic modulus E _B , and an intermediate layer having a longitudinal elastic coefficient at least larger than that of the B layer between the two layers A and B. A polishing cloth characterized by having M (Japanese Patent Laid-Open No. 10-
No. 156724)

A pad having a polishing layer, an intermediate layer having a higher elasticity than the polishing layer, and a soft underlayer, in which the intermediate layer is divided (JP-A-11-48131).

A polishing pad composed of urethane foam resin mixed with cerium oxide particles. (JP 2000-354950 and JP 2001-9697)

Abrasive grains are dispersed in a binder solution dissolved in a solvent and coated on a film.

Abrasive grains are dispersed in a binder resin, coated on a resin substrate, and the coated resin substrate is laminated with a member softer than the coating layer. Polishing pad (Japanese Patent Publication No. 2001-505489) Gazette and special table 2001-512375 gazette)

[0011]

The various polishing pads described above have the following problems. In this method, regarding the uniformity of the entire surface, the elastic polyurethane layer plays a role of equalizing the load applied to the wafer, but since soft synthetic leather is used for the outermost polishing layer, problems such as scratches occur. However, there is a problem that the flattening characteristic in a minute area is not good.

Even in the case of laminating polyurethane and non-woven fabric, the non-woven fabric layer plays the same role as the elastic polyurethane layer described above and obtains uniformity. In addition, since the polishing layer also has a hard polyurethane foam layer, it has superior flattening characteristics as compared with synthetic leather, but in recent years, the required level of flattening characteristics in a minute region has been improved and metal flatness has been improved. 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, but in this case, scratches frequently occur, which is not practical.

The structure of the polishing layer, the rigid layer, and the elastic layer is such that the surface polishing layer has an appropriate hardness that does not cause scratches, and the second rigid layer has a flattening characteristic that the hardness is not increased and deteriorates. It is a structure to improve by. This solves the problem of the above method, but in this case,
The thickness of the polishing layer is specified to be 0.003 inches or less, and when this thickness is actually used, the polishing layer is also scraped off, resulting in a short product life.

This method has the same basic idea as the above-mentioned method and tries to obtain a more efficient range by limiting the range of the elastic modulus of each layer. It is difficult to manufacture a polishing pad without any means for achieving it.

Also in this method, the basic idea is the same as that described above, but the intermediate rigid layer is divided into a predetermined size in order to further improve the uniformity in the wafer surface. However, this dividing step is costly and it is impossible to supply an inexpensive polishing pad. Further, polishing pads from these require expensive slurry to flow during polishing, leading to increased manufacturing costs.

In the methods 1 and 2, the abrasive grains are contained in the pad, but the concentration of the abrasive grains is not high, and it may be unavoidable to use it together with the slurry. Further, in, since the resin and the abrasive grains are simply mixed in the solvent, the particles agglomerate and cause scratches.

In the case of (1), the uniformity is improved by stacking layers, but the thickness of the coated fixed abrasive layer cannot be increased, or fine irregularities are formed on the surface. Has disappeared during use, and there is a problem that the life is not long. Also, these pads have similar problems to.

In addition, Japanese Patent Laid-Open No. 2001-505489 discloses an invention relating to a pad in which a fixed abrasive grain layer having a three-dimensional pattern is formed on a hard resin substrate and the substrate is supported by a layer softer than the substrate. Although disclosed, in the present invention, the hard resin substrate may impair the uniformity of the wafer polished using the polishing pad. On the contrary,
In the present invention, the hard resin substrate is abolished and the fixed abrasive layer is directly formed on the cushion layer to achieve extremely excellent in-plane uniformity.

According to the present invention, a fine pattern is formed on a semiconductor wafer, and in a polishing pad used in a polishing process for flattening fine irregularities of the pattern, a semiconductor that is slurryless and has less scratches. A wafer polishing pad is provided.

[0020]

That is, the present invention provides 20 to 1
In an abrasive material, characterized in that fine particle abrasive grains are dispersed in a resin containing an ionic group in the range of 500 eq / ton, the abrasive material is coated on a resin substrate, and the resin substrate is It is an abrasive characterized by being a resin having an A hardness of 90 or less.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a soft cushion layer is used as a resin base material that supports a resin layer (polishing layer) in which abrasive grains are dispersed, so that the entire surface of a silicon wafer after polishing is covered. The uniformity of the polishing rate is improved. It is essential that the resin base material (cushion layer) used in the present invention has Shore A hardness of 90 or less in order to ensure the uniformity of the wafer.

The cushion layer of the present invention has Shore A hardness.
In order to achieve 90 or less, it is preferable to use polyurethane resin foam or polyethylene resin foam, and rubber such as styrene-butadiene resin may be used.

The hardness of the cushion layer is preferably Shore A hardness of 40 to 85, particularly preferably 50 to 80. When the Shore A hardness is 90 or more, the uniformity of the polishing rate on the wafer surface when polished is impaired. Also, Short
When the eA hardness is 40 or less, the polishing layer may be peeled off and may not be polished simply by applying a slight stress to the laminated polishing body after coating the polishing layer.

Grooves are preferably formed in the polishing layer coated with the abrasive of the present invention. As the groove shape in the present invention, the groove pitch is preferably 10 mm or less. More preferably, the groove pitch is 10 mm or less, the groove width is 0.5 mm or more, and the groove depth is at least 0.8 times the thickness of the coating layer. More particularly preferably, the groove pitch is in the range of 4 mm to 8 mm, and the groove width is 0.
In the range of 5 mm to 2 mm, and the groove depth is the coating thickness.
0.8 times to 1.1 times is preferable.

If the groove pitch is 10 mm or more, the contact area between the wafer and the polishing pad becomes large, and vibration or noise may occur during polishing, or the wafer may come off the wafer holder in some cases. Similarly, if the groove width becomes too small, the contact area also increases and the above-mentioned situation occurs.
Further, if the groove depth is not more than a predetermined magnification, the groove of the pad disappears immediately after polishing, and the life of the pad is substantially shortened.

The method of forming the groove in the present invention is not particularly limited, and for example, an embossing molding method or a mechanical cutting method is preferably used. In the mechanical cutting method, the groove can be formed by, for example, cutting with a ceramic or metal blade or grinding with a ceramic grindstone or the like.

In the present invention, it is preferable that the opposite surface of the resin base material is laminated with a double-sided tape on a polyester resin film having a thickness of 150 μm or more, a polycarbonate plate, an ABS resin plate, a vinyl chloride resin plate or the like. . When not attached to the resin substrate, the pad itself may be greatly deformed when carried by only the coated polishing layer and the soft resin base material, and the deformation may cause cracks in the coated polishing layer. May occur or the coating layer may peel off.

The polyester resin film used in the present invention preferably has a thickness of 150 μm or more, more preferably 250 μm or more. The polyester resin film is preferably a stretched film, more preferably a biaxially stretched film.

In the present invention, it is preferable that a double-sided tape is laminated on the opposite surface of the polyester film on which the resin substrate is adhered with a double-sided tape. By using this double-sided tape, it becomes possible to attach the polishing material of the present invention to an ordinary rotary polishing device and easily polish it.

Further, in the present invention, the adhesive force of the double-sided tape to be attached to the polishing device is the adhesive force of the polyester resin film side rather than the adhesive force of the side attached to the polishing device. Is preferably large. If the strength of the adhesive force applied to the polishing machine side is greater than the adhesive force of the resin substrate side, after using the polishing pad, peel off the unnecessary pad from the device again, leaving only the double-sided tape on the device side. Therefore, it is necessary to peel off the remaining double-sided tape again, which deteriorates workability.

The thickness of this resin substrate (cushion layer) also affects the uniformity of polishing in polishing, and is preferably 0.
A thickness in the range of 3 mm to 2 mm is good. When the thickness of the cushion layer is 0.3 mm or less, the amount of deformation is small and the uniformity deteriorates. On the other hand, if the thickness is 2 mm or more, the amount of deformation becomes large, and the flatness of the wafer surface is deteriorated by polishing.

The resin that disperses the abrasive grains used in the present invention has a constitution in which two or more kinds of resins having a glass transition temperature of 60 ° C. or higher and resins having a glass transition temperature of 30 ° C. or lower are mixed. preferable. When only a resin having a glass transition temperature of 60 ° C. or higher, the coating film shrinks when coating and drying, the coating film cannot withstand the stress, and wrinkles occur on the surface. Further, when the coating is performed with a resin having a glass transition temperature of 30 ° C. or less, the coating film surface is good, but the surface becomes sticky, and the frictional resistance during polishing is remarkably increased, so that stable polishing cannot be performed. Therefore, it is necessary to mix two or more kinds of resins having different glass transition temperatures and balance them.

As the resin for dispersing abrasive grains used in the present invention, polyester resin, polyurethane resin and acrylic resin are mentioned as preferable examples, and polyester resin or polyester polyurethane resin is particularly preferable.
This polyester resin may be modified with urethane, acrylic or the like.

The polyester resin in the present invention is obtained by polycondensing a polyvalent carboxylic acid and a polyvalent alcohol.

The polycarboxylic acid in the present invention is mainly composed of dicarboxylic acids. As dicarboxylic acids,
For example, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid and 1,5-naphthalic acid, p
Aromatic oxycarboxylic acids such as -oxybenzoic acid p- (hydroxyethoxy) benzoic acid and the like can be used. Aromatic dicarboxylic acid is 40m of polyvalent carboxylic acid component
It is preferable to use ol% or more, and more preferably 60 mol% or more. If the content of the aromatic dicarboxylic acid is less than this range, the glass transition temperature of the resin is lowered. The dicarboxylic acids preferably used in the present invention are terephthalic acid and isophthalic acid. These are preferably used in an amount of 50 mol% or more of the aromatic dicarboxylic acid.

In the present invention, other dicarboxylic acids include succinic acid, adipic acid, azelaic acid, sebacic acid,
Aliphatic dicarboxylic acid such as dodecanedicarboxylic acid, fumar
Unsaturated aliphatic dicarboxylic acids such as acid, maleic acid, itaconic acid, hexahydrophthalic acid, tetrahydrophthalic acid, and (unsaturated cyclohexanedicarboxylic acid, cyclohexenedicarboxylic acid, dimer acid, trimer acid, tetramer acid, etc. ) Alicyclic dicarboxylic acids and the like can be used. In the present invention, a small amount of tri- and tetracarboxylic acids such as trimellitic acid, trimesic acid and pyromellitic acid may be contained if necessary.

Examples of the polyhydric alcohol component in the present invention include ethylene glycol and propylene glycol.
1,3-propanediol, 1,4-butanedio-
1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol
, Dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, 1,4-cyclohexanedimethanol, spiroglycol, 1,4-phenyleneglycol, 1,4 -Ethylene oxide adduct of phenylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, tricyclodecane dimethanol, dimer diol, hydrogenated dimer diol, etc. Diol, bisphenol Of ethylene oxide adduct and propylene oxide adduct of hydrogen A, ethylene oxide adduct of hydrogenated bisphenol A and propylene oxide adduct, and the like.
And, if necessary, ring-opening polymerization of trimethyls such as trimethylolethane, trimethylolpropane and glycerol, tetraols such as pentaerythritol, and lactones such as ε-caprolactone. The resulting lactone polyester polyols can be used.

In the present invention, the resin preferably has an ionic group. As the ionic group contained in the resin, an anionic group such as a carboxyl group, a sulfonic acid group, a sulfuric ester group, a phosphoric acid group, or a salt thereof (hydrogen salt, metal salt, ammonium salt) group, or a first group Grade 3rd
It is a cationic group such as a primary amine group, and preferably a carboxyl group, an ammonium carboxylate group, a sulfonic acid group, an alkali metal sulfonate group or the like can be used.

Taking the case of polyester resin as an example,
The ionic group-containing resin will be described. These ionic groups are preferably contained in the resin in a copolymerized form.
Examples of the sulfonic acid metal group-containing compound copolymerizable with the polyester resin include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7dicarboxylic acid and 5 [4-sulfophenoxy].
A metal salt such as isophthalic acid can be used. Further, an ionic group can be introduced at the terminal of the polymer by using a monocarboxylic acid such as sulfobenzoic acid and its metal salt. Of course, the carboxyl group remaining at the terminal of the polyester resin can be effectively used. In addition,
Furthermore, trimellitic anhydride is added at the end of polymerization of the polyester resin. By adding a polyvalent carboxylic acid anhydride such as pyromellitic anhydride and phthalic anhydride, it is possible to introduce more carboxyl groups into the resin terminal. The carboxyl group can be effectively used as an ionic group by post-treatment and neutralization with ammonia, alkali metal, amines or the like. As the metal salt, Li, Na,
Examples thereof include salts of K, Mg, Ca, Cu, Fe and the like.

The content of these ionic groups is 2 with respect to the resin, including the groups of sulfonic acid groups and / or salts thereof.
It is 0 to 1000 eq / ton. Such an ionic group is required for developing the solubility and water dispersibility of the resin.

In the present invention, the resins may be used alone or in combination of two or more if necessary. Further, it can be mixed with an amino resin, an epoxy resin, an isocyanate compound or the like in a molten state or a solution state, and further, it can be partially reacted with these compounds.

(Water Dispersion Manufacturing Method) The resin used in the present invention is
Since it has water dispersibility, it is possible to obtain a micro water dispersion by self-emulsifying. The particle size of such a microdispersion is about 0.01 to 1 μm.

As a concrete method of self-emulsification, in the case of a polyester resin having a carboxyl group, a sulfonic acid group, a sulfuric acid ester group or a phosphoric acid group as an ionic group, (1) the polyester resin is dissolved in a water-soluble organic compound. . (2) Add cations for neutralization. (3) Add water. (4) Remove water-soluble organic compounds by azeotropic distillation, dialysis, etc.

As an ionic group, an anionic group such as a group of a carboxyl group, a sulfonic acid group, a sulfuric acid ester group, a salt of a phosphoric acid group (metal salt, ammonium salt), or a primary to tertiary amine group, etc. In the case of a polyester resin having a cationic group, (1) the polyester resin is dissolved in a water-soluble organic compound. (2) Add water. (3) Water-soluble organic compounds are removed by azeotropic distillation, dialysis, etc. The following procedure can be illustrated. Emulsifier during emulsification,
It is also possible to use a surfactant and the like together.

As the water-soluble organic compound, a water-soluble solvent having a relatively low boiling point such as methanol, ethanol, propanol, butanol, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, butyl cellosolve or ethyl cellosolve can be preferably used.

Sources of cations for neutralization include alkali metal hydroxides, alkali metal carbonates,
Alkali metal hydrogen carbonate, ammonia, triethylamine, monoethanolamine, diethanolamine, triethanolamine, dimethylethanolamine, diethylethanolamine, monomethyldiethanolamine, monoethylethanolamine, isophorone, and other amines, amino alcohols, cyclic amines Etc. can be used.

Further, in the present invention, it is preferable to mix two or more kinds of resins having an ionic group. The cousin preferably has a glass transition temperature of 60 ° C. or higher, and the other glass transition temperature of 30 ° C. or lower. If the resin plate is coated with only the resin having a glass transition temperature of 60 ° C. or higher, a crack is generated on the coated surface during drying, and a good coating film cannot be obtained.

The fine-grained abrasive grains used in the present invention are 5n.
It is preferably from m to 1000 nm. Particle size is 5
When it is less than nm, when it is dispersed with the polyester resin, it becomes very difficult to mix the polyester resin and it cannot be substantially manufactured. Further, when the particle diameter exceeds 1000 nm, there is a possibility that the object to be polished may be seriously damaged when polishing is performed with an abrasive manufactured using the particle.

The types of abrasive grains are preferably zirconium oxide, ferric chloride, chromium oxide, diamond and the like, and particularly preferably cerium oxide, silicon oxide and aluminum oxide. For these abrasives, the optimum abrasive grains can be appropriately selected for polishing the silicon wafer itself, the silicon oxide film deposited on the silicon wafer, and various metal films such as AL and Cu. Especially for the silicon oxide film, cerium oxide and silicon oxide are preferable, and for the metal film, aluminum oxide is preferable.

In the present invention, the content of the abrasive grains in the dispersed resin is preferably 60 wt% to 95 wt%, and particularly preferably 75 wt% to 95 wt%. When the content of abrasive grains is 60 wt% or less, the volume content of the abrasive grains decreases,
The polishing rate may decrease or the polishing rate may not be achieved. Further, when the content of the abrasive grains is 95 wt% or more, the strength of the coating film obtained by the coating cannot be obtained, and the coating film peels off during polishing, which causes scratches.

In the present invention, the thickness of the abrasive grain coating layer is preferably 350 μm or more and 2 mm,
Particularly preferably, it is 400 μm or more and 1 mm or less. When the coating thickness is 350 μm or less, when the polishing is actually performed, the coating layer is also worn away and the life of the abrasive is shortened, which is not practical. On the other hand, when the coating thickness exceeds 2 mm, when the coating is dried after coating, large cracks occur on the surface, and a beautiful coating film cannot be obtained.

Furthermore, in the present invention, the adhesion strength of the polishing coating film to the resin substrate is 1 m in accordance with JIS K-5400.
When a cross cut test of 100 square meters is used, it is preferably 90 or more, and particularly preferably 100.
A film having a value of less than 90 has a weak adhesive force, and when polished, peeling of the coating film occurs, which causes scratches.

In the present invention, the soft substrate coated with the abrasive and the hard resin layer are laminated, but the coated soft resin substrate and the hard resin layer are bonded by an adhesive or a double-sided tape. It is preferable to stick together.

The adhesive or the double-sided tape in this case is not particularly limited, but acrylic resin type, styrene-butadiene rubber type and the like are preferable. In addition, the adhesive strength of the layer according to JIS Z 0237 must be 600 g / cm or more in a 180 degree peel test.
If the adhesive strength is less than 600 g / cm, peeling between the resin substrate and the cushion layer may occur during polishing.

Further, in the present invention, it is preferable that the abrasive material has a structure in which a resin in which fine particle abrasive particles are dispersed is coated on a resin substrate.

The base material used for coating the base material is also polyester-based, polyamide-based, polyimide-based, polyamide-imide-based, acrylic-based, cellulose-based, polyethylene-based, polypropylene-based, polyolefin-based, polyvinyl chloride-based, Examples include polycarbonate, phenol-based, urethane-based resins, silicone-based resins and the like.

Further, in order to obtain the above-mentioned suitable hardness, a foam of those resins may be used. Further, if the resin body is a resin having a hardness within the above range, it is not necessary to contain bubbles. When a foam is used, the foaming method is not particularly limited, and examples thereof include a water foaming method, a hot gas generating method, and a method of mixing microballoons.

When polishing an uneven silicon wafer having a pattern formed on its surface with the polishing material of the present invention, the polishing material is brought into contact with the silicon wafer to be polished by applying a certain load and moves relatively. The silicon wafer can be planarized by polishing with. In this case, the movement of the silicon wafer and the polishing material may be linear movement or curved movement.

When polishing a silicon wafer according to the present invention, it is possible to perform polishing without any intervention between the silicon wafer and the polishing material, but it is preferable to reduce scratches and the like. May be polished while flowing pure water. When the object to be polished is silicon oxide on a silicon wafer, an alkaline aqueous solution may be flowed, and when the object to be polished on the silicon wafer is a metal such as aluminum, tungsten, or copper, those metal surfaces are used. The polishing may be carried out while flowing an acidic aqueous solution capable of oxidizing. In these cases, pure water to be supplied, alkaline aqueous solution,
Acidic aqueous solution should be at least 15 mg / cm ² · m per pad area
It is better to supply the amount of in.

In the present invention, polishing may be carried out while dropping a surfactant for the purpose of reducing the frictional resistance between the wafer and the polishing material, reducing scratches, and controlling the polishing rate. The surfactant may be dropped alone on the abrasive material of the present invention, or may be previously mixed and dropped into the above-mentioned pure water or an alkaline aqueous solution or an acidic aqueous solution.

[0061]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 In a flask equipped with a stirring blade,
30 parts by weight of water-dispersion polyester resin TAD1000 (manufactured by Toyobo Co., Ltd., glass transition temperature 65 ° C., ionic group amount 816 eq / ton, solid content concentration 30 wt%), water dispersion polyester resin TAD3000 (manufactured by Toyobo Co., Ltd. glass transition temperature 3
0 ℃ Ionic group amount 815eq / ton Solid content concentration 30wt%) 40
By weight, 3 parts by weight of the cross-linking agent Cymel 325 (manufactured by Mitsui Cytec Co., Ltd.) and 0.7 part by weight of the defoaming agent Surfynol DF75 (manufactured by Nisshin Chemical Co., Ltd.) were mixed with stirring, and then cerium oxide powder (manufactured by Baikowski Co., Ltd. average). 100 parts by weight of a particle diameter of 0.2 μm) were sequentially added, and the mixture was stirred so as to be uniform. The obtained coating liquid was in the form of paste and was used as a polishing layer coating liquid. Next, a 0.8 mm thick polyurethane foam sheet (THM ShoreA hardness 67 made by Sekisui Chemical Co., Ltd.) and a 0.5 mm thick polycarbonate substrate (Shore A95 or more made by Mitsubishi Engineering Plastics Co., Ltd.) double-sided tape # 5782 (Sekisui Chemical Co., Ltd. made) ) To apply a surface load of 1 kg / cm 2 to produce a bonded base material, and on the foamed polyurethane side of the base material,
The coating liquid prepared above was coated with a table die coater to a thickness of about 400 μm. The substrate coated with the polishing layer was dried in a hot air oven at 110 ° C. for about 20 minutes, gradually cooled, and taken out.

The obtained polishing layer had a thickness of about 350 μm on the layered polycarbonate substrate laminated polyurethane substrate, and its cross section was observed with a scanning electron microscope to find that the cerium oxide fine particles did not aggregate. It was confirmed that they were uniformly dispersed. Moreover, when the cross-cut tape was peeled off from the obtained coating film, the remaining number was 100.
No peeling was observed. Next, a double-sided tape was applied again to the non-coated surface of this coating film sheet while applying a surface load of 1 kg / cm 2 to obtain a bonded abrasive. The adhesive strength between the coating film substrate and the polycarbonate substrate was subjected to a 180-degree peeling test with a tensile tester, and as a result, an adhesive force of 1000 g / cm or more was found. The polishing characteristics of the obtained abrasive are shown in Table 1. It was confirmed that the obtained abrasive had a high polishing rate, had extremely excellent flattening characteristics, and had good uniformity.

(Example 2) As in Example 1, the water-dispersed polyester resin TAD3000 was used instead of TAD2000.
(Made by Toyobo Co., Ltd. glass transition temperature 20 ° C, amount of ionic group 10
An abrasive was manufactured in the same manner as in Example 1 except that 20 eq / ton solid content concentration of 30 wt%) was used, and the substrate to be coated was changed from polyurethane foam resin to styrene butadiene rubber (Shore A55). Similarly, the results are also shown in Table 1. It was confirmed that the polishing rate was high, the flattening characteristics were extremely excellent, and the uniformity was also good.

(Example 3) As in Example 1, the water-dispersed polyester resin TAD1000 was used instead of MD1200 (manufactured by Toyobo Co., Ltd., glass transition temperature 67 ° C., ionic group amount 300 eq /
A ton solid content concentration of 34 wt% was used, and an abrasive was manufactured in the same manner as in Example 1 except for the above. Similarly, the results are also shown in Table 1. It was confirmed that the polishing rate was high, the flattening characteristics were extremely excellent, and the uniformity was also good.

(Example 4) After coating the foamed polyurethane resin in the same manner as in Example 1, the coated surface was again coated with a thickness of about 400 µm, and thereafter the same production was carried out. The thickness of the obtained coating film is
The film thickness was about 700 μm, and the number of remaining sheets subjected to the cross-cut tape test was 100, showing no change in the coating film. When polishing was performed using this abrasive, it was confirmed that the polishing rate was high, the flattening characteristics were extremely excellent, and the uniformity was also good.

(Example 5) The same procedure as in Example 1 was repeated except that the hard resin layer laminated with the soft resin substrate in Example 1 was changed from polycarbonate to a biaxially stretched polyester film having a thickness of 250 μm. I did. When polishing was performed using this abrasive, it was confirmed that the polishing rate was high, the flattening characteristics were extremely excellent, and the uniformity was also good.

Comparative Example 1 An abrasive was manufactured in the same manner as in Example 1 except that the water-dispersed polyester resin TAD3000 was not mixed in Example 1 and the surface of the abrasive layer after drying was greatly cracked. . When polishing was carried out with such an abrasive, a part of the coating film was peeled off, and many scratches were observed on the polished wafer.

(Comparative Example 2) An abrasive material was prepared in the same manner as in Example 1 except that the water-dispersed polyester resin TAD1000 was not mixed in Example 1, and a good coating film was obtained, but the surface was It was a little sticky. When polishing was carried out with such an abrasive, the wafer adhered to the surface of the abrasive, violent vibration occurred during polishing, and finally the wafer came off the wafer holder.

(Comparative Example 3) In Example 1, a bonded abrasive was produced by applying a urethane foam resin substrate and a polycarbonate substrate with almost no surface load. The adhesive strength between the foamed polyurethane resin substrate and the polycarbonate substrate of the produced abrasive was measured by the 180-degree peel test to be 400 g / c.
There was only an adhesive force of m. When a polishing test was performed with such an abrasive, after processing several wafers,
Peeling occurred between the foamed polyurethane resin substrate coated with the polishing fine particles and the polycarbonate substrate during polishing, and polishing could not be performed.

(Comparative Example 4) In Example 1, cerium oxide powder (produced by Baikowski Co., Ltd. average particle diameter 1.5 μm) was used.
m) The abrasive was manufactured in the same manner except that the amount was changed to 500 parts by weight. The obtained polishing layer has very weak adhesion and film strength, and when the substrate material is bent, the coating film peels off,
The polyethylene foam layer could not be laminated.

Comparative Example 5 600 parts by weight of a thermoplastic polyester resin (Vylon RV200 manufactured by Toyobo Co., Ltd.) and 400 parts by weight of silica powder having a diameter of 0.5 μm were melt-mixed at a temperature of Tg or higher of the resin. The viscosity was so high that mixing was impossible.

COMPARATIVE EXAMPLE 6 800 parts by weight of a thermoplastic polyester resin (Vylon RV200 manufactured by Toyobo Co., Ltd.) and 200 parts by weight of silica powder having a diameter of 0.5 μm were melt-mixed at a temperature not lower than the Tg of the resin, and a release agent. Was poured or poured into a coated container to obtain a disc-shaped polishing pad having a thickness of 10 mm and a diameter of 60 cm. When the cross section of the obtained polishing pad was observed with a scanning electron microscope, it was observed that silica particles were aggregated into lumps of several microns.

(Comparative Example 7) Polyether 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 a surfactant (dimethylpolysiloxane / polyoxyalkyl copolymer SH192 manufactured by Toray Dow Corning Silicone Co., Ltd.) and cerium oxide (Siebel Hegner nanoscale ceria) 5000
After adding the parts by weight, the stirrer was replaced and the curing agent (4,4 '
770 parts by weight of methylene-bis [2-chloroaniline] was added while stirring, and an attempt was made to stir at about 400 rpm with a stirrer, but the viscosity rapidly increased, and stirring was impossible.

(Comparative Example 8) 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 a surfactant (dimethylpolysiloxane / polyoxyalkyl copolymer SH192 manufactured by Toray Dow Corning Silicone Co., Ltd.) and cerium oxide (Siebel Hegner nanoscale ceria) 600
Add parts by weight and stir at about 400 rpm with a stirrer to make a mixed solution, then replace the stirrer and add 770 parts by weight of a hardening agent (4,4′-methylene-bis [2-chloroaniline] while stirring. After stirring for about 1 minute, the mixed solution was put into a pan-type open mold and post-cured in an oven at 110 ° C. for 6 hours to produce a polyurethane foam block.The obtained polyurethane foam had a Shore A hardness of 65. ,
The compressibility was 0.5%, the specific gravity was 0.95, and the average bubble diameter was 35 μm. When the cross section of the obtained polishing pad was observed with a scanning electron microscope, it was observed that the cerium oxide particles were aggregated to form a lump of several microns.

(Comparative Example 9) In Example 1, when a foamed polyurethane resin substrate which is not laminated with a polycarbonate substrate was coated, a large warp occurred in the drying step and a good polishing pad could not be obtained. It was

[0077]

[Table 1]

(Evaluation of Polishing Characteristics) SPP600S manufactured by Okamoto Machine Tool Co., Ltd. was used as a polishing apparatus to evaluate polishing characteristics. An interference-type film thickness measuring device manufactured by Otsuka Electronics Co., Ltd. was used for measuring the film thickness of the oxide film. As the polishing conditions, a chemical solution was used, and only ultrapure water or KOH added to ultrapure water to adjust the pH to 11 was dropped during polishing at a flow rate of 150 ml / min.
The polishing load is 350 g / cm2, the number of rotations of the polishing plate is 3
The rotation speed was 5 rpm and the wafer rotation speed was 30 rpm.

In the evaluation of polishing characteristics, a thermal oxide film of 0.5 μm was deposited on an 8-inch silicon wafer, predetermined patterning was performed, and then the oxide film of 1 μm was formed by p-TEOS.
m was deposited to produce a patterned wafer having an initial step difference of 0.5 μm, 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 flattening characteristics. One is a local step, which is a step in a pattern in which lines with a width of 270 μm are arranged in a space of 30 μm, and the other is to examine the amount of abrasion of the bottom part of the space in which a line with 30 μm lines is arranged in a space of 270 μm. It was The average polishing rate was the average value of the 270 μm line portion and the 30 μm line portion. For scratch evaluation, the oxide film surface of the polished 6-in silicon wafer was 0.2 μm using Topcon Wafer Surface Inspection System WM2500.
The number of streaks of m or more was evaluated.

[0080]

According to the present invention, since the polishing layer contains abrasive grains, it is not necessary to use an expensive slurry for polishing, and low-cost processing can be provided. Further, there is no aggregation of abrasive grains in the polishing layer, scratches are less likely to occur, and the in-plane uniformity of the polishing rate of the object to be polished is extremely good.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) B24D 11/00 B24D 11/00 M P C09K 3/14 550 C09K 3/14 550C 550K 550L F term (reference) 3C058 AA02 AA09 CB02 CB04 DA02 DA17 3C063 AA10 BA24 BB01 BB03 BC03 BF02 BG01 BG08 BG22 BH12 BH19 EE10 EE26 FF23

Claims (9)

[Claims] 1. An abrasive material comprising a polishing layer in which fine particle abrasive grains are dispersed in a resin containing an ionic group of 20 to 1500 eq / ton, and a cushion layer formed by coating the polishing layer. The Shore A hardness of the cushion layer is 90 or less. 2. A polishing material comprising a resin substrate having a thickness of 150 μm or more bonded to the surface of the cushion layer opposite to the surface coated with the polishing layer, wherein the hardness of the resin substrate is the cushion. The abrasive according to claim 1, which has a hardness higher than that of the layer. 3. An abrasive material, wherein the resin substrate and the cushion layer are attached to each other with a double-sided tape, and another double-sided tape is attached to the other surface of the resin substrate. The abrasive material according to claim 1 or 2, wherein the adhesive strength is different, and the adhesive strength between the back surface and the front surface of each double-sided tape is different. 4. The resin constituting the polishing layer is made of a resin selected from polyester resin, polyurethane resin, polyester polyurethane resin and acrylic resin,
A resin having a glass transition temperature of 60 ° C. or higher and a resin having a glass transition temperature of 30 ° C. or lower are mixed together.
Abrasive according to. 5. The polishing material according to claim 1, wherein the polishing layer has a large number of grooves. 6. The thickness of the cushion layer is 0.3 mm
The abrasive according to any one of claims 1 to 5, wherein the abrasive has a diameter of 2 mm. 7. The resin according to any one of claims 1 and 6 to 11, wherein the content of the fine particle abrasive grains in the resin is 60 wt% to 95 w.
Abrasive material characterized by being t%. 8. A polishing method for flattening the surface of a silicon wafer using the polishing material according to any one of claims 1 to 7, wherein the polishing is performed while flowing a liquid between the polishing material and the silicon wafer. Polishing method. 9. The polishing method according to claim 8, wherein the liquid is an acid or alkali liquid.