JP2002137160A - Pad for polishing, polishing device, and polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce adhesion of dust to the surface of a material to be polished, to reduce the occurrence of a scratch flaw, to make flattening characteristics compatible, and further to remove fine recess and protrusion of a semiconductor wafer itself before machining a recess and a protrusion, that is, a defect represented into waviness and nanotopology, by a simple polishing method. SOLUTION: A polishing pad is formed mainly of urethane resin having surface D hardness of 65 or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a workpiece is pressed against a rotating elastic pad while supplying a polishing liquid containing processing abrasive grains and / or while supplying a polishing liquid containing no abrasive grains. A polishing pad used for chemical mechanical polishing (CMP) or the like for finishing the surface of the workpiece to a mirror surface while performing the polishing, or for preferentially polishing the convex portion of the unevenness on the surface of the workpiece with an abrasive. And a polishing apparatus and a polishing method using the same.

[0002]

2. Description of the Related Art In order to realize a multi-layer wiring in manufacturing a semiconductor with a high degree of integration, it is necessary to completely flatten the surface of an insulating film. Heretofore, SOG (Spin-On-Glass) method and etch-back method (P. Elikins, K. Reinhardt, and R. La.
yer, "A planarization process for double metalCMOSu
sing Spin-on Glass as a sacrificial layer, "Proceed
ing of 3rd International IEEE VMIC Conf., 100 (198
6)) and the lift-off method (K. Ehara, T. Morimoto, SM
uramoto, and S.Matsuo, "Planar Interconnection Techn
ology for LSI FabricationUtilizing Lift-off Proces
s ", J. Electrochem Soc., Vol. 131, No. 2, 419 (1984).

[0003] As for the SOG method, this is a flattening method utilizing the fluidity of the SOG film, but it is impossible to carry out complete flattening by itself. The etch-back method is the most frequently used technique, but has a problem of dust generation due to simultaneous etching of a resist and an insulating film, and is not an easy technique in terms of dust management. Then, the lift-off method has a problem that the stencil material to be used cannot be lifted off because the stencil material is not completely dissolved at the time of lift-off, and the controllability and the yield are incomplete.

Therefore, the CMP method has recently attracted attention. This is a method of pressing a workpiece against a rotating elastic pad and performing preferential polishing with a polishing pad on the surface of the workpiece with relative movement while performing relative movement. Widely used. In recent years, fine unevenness of a semiconductor wafer itself before unevenness processing is performed, that is, a wafer or nanotopology.
A surface defect, which has not been a problem in the past such as y, has become a problem, and a double-side polishing method, a method of polishing while flowing an alkali, and the like have been performed.

[0005]

However, in such a CMP method, there are problems such as scratches, dust adhesion, poor global flatness, etc., which occur on the surface of the object to be polished. For example, if such dust adheres or scratches occur on the surface to be polished such as an interlayer insulating film, when a wiring made of an Al or Cu-based metal or the like is formed thereon in a later process, a step breakage or the like occurs. In addition, there is a possibility that a decrease in reliability such as deterioration of electromigration resistance may occur. In addition, in polishing of a non-magnetic substrate for an HDD (Hard Disk Drive) or the like, a dropout or the like may cause a loss of a reproduced signal. It is considered that the occurrence of scratches is caused by agglomerates due to poor dispersion of the abrasive particles. In particular, a polishing slurry that employs alumina as polishing particles used for CMP of a metal film has poor dispersibility, and has not completely prevented scratch damage. At present, the cause of dust adhesion is not well understood. It is common sense that a hard polishing pad is desirable to improve global flatness, but conversely, it is considered that both can not be compatible because dust tends to adhere and scratches are likely to occur.

For example, Japanese Patent Application Laid-Open Publication No. Hei 8-500622 and Japanese Patent Laid-Open Publication No. 2000-34416 have attempted to do so, but have failed to achieve both dust adhesion / scratch flaws and flattening characteristics. In particular, urethane material has been attracting attention and has been studied.
Only those having a hardness of about 63 exist on the market. If it is more than this, scratches are likely to occur, so there is room for improvement in the flattening characteristics, but conventionally no improvement was possible.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce dust adhering to the surface of an object to be polished, to reduce scratches, and to achieve flattening characteristics.

[0008] Further, fine irregularities of the semiconductor wafer itself before the irregularity processing, that is, waveguide, n
An object of the present invention is to provide a polishing pad, a polishing apparatus, and a polishing method capable of removing a defect expressed as an antoology by a simple polishing method.

[0009]

In order to solve the above-mentioned problems, the present invention has the following arrangement. That is, (1) a polishing pad characterized by being mainly composed of a urethane resin having a surface D hardness of 65 or more. (2) The polishing pad according to the above (1), wherein the surface D hardness is 70 or more. (3) The polishing pad according to the above (1) or (2), comprising a filler which is hydrophilic and substantially insoluble in water. (4) The polishing pad according to any one of the above (1) to (3), further having a void apart from the particles formed of the fibrous material and / or the composite thereof. (5) The polishing pad according to any one of the above (1) to (4), comprising inorganic fine particles. (6) The polishing pad according to any one of (1) to (5), further including a water-soluble substance. (7) The polishing pad according to the above (6), wherein the polishing pad contains 0.01 wt% to 10 wt% of a water-soluble substance. (8) The polishing pad according to any one of the above (1) to (7), wherein the water absorption is 2.0% by weight or more. (9) A polishing apparatus using the polishing pad according to any one of (1) to (8). (10) A polishing method using the polishing pad according to any one of (1) to (8). (11) A method for manufacturing a semiconductor wafer or a semiconductor chip, characterized by processing using the polishing pad according to any one of the above (1) to (8).

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. In the present invention, by providing a polishing pad mainly made of a urethane resin having a surface D hardness of 65 or more, the polishing pad itself can be kept at a high level without causing dust adhesion and scratching, which have conventionally been in a trade-off relationship. Since the hardness can be increased, very good flattening characteristics can be realized.

Since the surface D hardness is mainly made of urethane resin of 65 or more, the wettability of the polishing pad surface is improved, and the adhesion of dust to the surface of the object to be polished is reduced although the detailed mechanism is unknown. In connection with that, it is thought that scratch damage can be reduced. At this time, for example, the mixed hydrophilic and substantially water-insoluble filler is insoluble in water, and therefore, changes in the properties of the dispersion regardless of whether or not it contains free abrasive grains used for polishing. , And can be satisfactorily polished.

The term "substantially insoluble in water" means that the solubility in water at 25 ° C. is 1% or less. Hydrophilicity is basically an expression of the property of absorbing water in a resin, and does not mean that water is held in voids between macroscopic resins. That is, when evaluating hydrophilicity, a test piece taken out of water after immersion in water for 24 hours was placed in a sealed container, and centrifugal force of 1400 G to 1450 G was applied for 30 seconds, and moisture absorption was measured in a state where water was shaken off. The weight increase rate is determined according to the following equation 1. Weight increase rate (%) = {(moisture absorption weight−dry weight) / dry weight} × 100 (Equation 1) Here, the hydrophilicity of the filler means the weight increase rate when immersed in 50 ° C. water for 24 hours. Refers to characteristics of 2.0% or more. In the present invention, the weight increase rate is more preferably about 5 to 20%. If the height is too high, the polishing pad swells during polishing, and the flatness of the polishing pad surface is impaired. It is also possible to use a water-absorbing polymer of 10000%.

The mixing amount of the filler depends on the above-mentioned weight increase rate. Basically, it can be reduced when the weight increase rate is large, and increased when the weight increase rate is small. The mixing amount of the filler is preferably 0.1% by weight or more. If the amount of the filler is less than 0.1% by weight, the effect cannot be sufficiently confirmed. However, if the amount is more than 0.1% by weight, adhesion of dust and scratches can be reduced. When the mixing ratio is small, the effect is small, and when the mixing ratio is large, the effect is large, but the physical properties of the pad are often deteriorated. That is, the hardness of the pad decreases, the bending strength is weak, and the pad is easily brittle. For this reason, it is preferably used in an amount of 3 to 60% by weight, more preferably 20 to 55% by weight.

As the resin constituting the polishing pad, a polyurethane resin is preferably used, and derivatives, copolymers, grafts and the like can be used. These may be mixed, but it is important to mix them so that hardness is obtained. For this reason, it is preferable that the introduction of the isocyanate is also polyfunctionalized. Commonly used bifunctional diisocyanates such as diphenylmethane diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, dicyclohexylmethane diisocyanate (MDI, TDI,
NDI, XDI, HMDI) and the like are preferably used. It is preferable to use a polyol component for the urethane reaction. Similarly, the polyol component is preferably polyfunctional rather than difunctional. A cross-linking agent such as methylenebischloroaniline (MOCA) can be used in place of the polyol component, but in this case, the problem of dust adhesion and scratching is likely to occur, and the hydrophilicity is substantially insoluble in water. This problem can be improved by including the filler of (1). Similarly, methylenebischloroaniline can be additionally used together with the polyol component. It is also possible to control the molding speed and structure of the resin plate by utilizing the fact that the addition of an amine component increases the gel acceleration during curing of urethane.
The isocyanate may be in the form of a prepolymer, but when impregnating into the filler or mixing with the filler, it is better to design the isocyanate having a low viscosity. As can be seen from the above, a mixture of various isocyanate components and polyol components may be used. There are infinite combinations of urethane chemical structures to be selected. In short, it is important that the D hardness after curing after molding is 65 or more.

As another method, for example, it is also effective to mix inorganic fine particles to improve the hardness. The technology disclosed in nanocomposites and the like can also be applied and developed. Specifically, silica, ceria, alumina, zirconia, titanium, tungsten, barium carbonate, manganese dioxide, barium sulfate, carbon black, clay such as montmorillonite, crystals of zeolite and the like can be used as the inorganic fine particles. Also, a mixture of these is also possible. It is also possible to modify the surface in advance to improve the familiarity with urethane. As the particle diameter, a particle diameter of about 3 nm to about 50 μm can be used, but if it is too large, the risk of scratching increases. For this reason, it is more preferable that the thickness be 20 μm or less, more preferably 5 μm or less. Silica, ceria, alumina, zirconia, titanium, tungsten, barium carbonate, manganese dioxide, barium sulfate, carbon black, clay such as montmorillonite, fine particles such as zeolite, etc. Yes, it can be mixed up to about 80%. When mixed at a high concentration, not only the effect of increasing the hardness of the polishing pad,
This is effective as a so-called fixed abrasive polishing pad containing abrasive grains. In this case, the effect is small if the particle size is small,
The particle diameter is preferably 30 nm or more, and more preferably 100 nm or more from the viewpoint of improving the polishing rate. By changing the particle size and mixing amount of these fine particles, it is possible to manufacture a polishing pad that matches the characteristics of the object to be polished. Here, in the case of secondary aggregated particles, the particle diameter refers to the aggregated diameter. Of course, monodispersed particles (such as colloidal particles) refer to the single particle diameter.

The D hardness after forming the polishing pad of the present invention is 65.
It is important that this is the case. If it is less than 65, it becomes too soft, and dishing and erosion are likely to occur. In order to further increase the polishing rate, it is preferably 70 or more, and more preferably 80 or more. However, when the D hardness is 90 or more, the good abrasion resistance and toughness specific to urethane tend to decrease and tend to become brittle. Therefore, the higher the D hardness, the better the handleability when a sheet-like filler is mixed. Leads to
The water absorption of the polishing pad decreases. Urethane resin is
It is well compatible with the hydrophilic filler and coats the entire surface of the filler, so that the water absorption of the resin as a whole is greatly reflected in the water absorption of the entire polishing pad.

The water absorption of the polishing pad itself can be measured in the same manner as the measurement of the rate of weight increase. In this case, the formed polishing pad piece is immersed in water at 25 ° C., the weight change after 5 hours is obtained, and the weight change can be calculated based on Equation 2. Water absorption (wt%) =
{(Moisture absorption weight-dry weight) / dry weight} x 100 (Equation 2) Therefore, when using urethane having high hardness, a small amount of a hydrophilic prepolymer such as polyalkylene glycol (polyethylene glycol, polypropylene glycol, etc.) is used. By suppressing the decrease in hardness and increasing the water absorption, a material having a water absorption of 2.0% by weight or more can be produced. With this improved policy and method, the problems of dust adhesion and scratches can be avoided. In order to improve brittleness, it is convenient to introduce a rubber component having a carbon double bond.

In the present invention, even if the hardness is further increased and the D hardness exceeds 90, problems such as scratches and dust adhesion do not occur, and the present invention can be used. For this reason, it is possible to exhibit good polishing and flattening characteristics which could not be obtained conventionally.

Used in the polishing pad of the present invention,
Fillers that are hydrophilic and substantially insoluble in water include, for example, celluloses, starches, polysaccharides such as chitin, proteins, acrylics such as polyacrylic acid and polymethacrylic acid, aramids, polyamides, and polyvinyl alcohols. And a resin such as ethylene-vinyl alcohol copolymer or polyvinyl polypyrrolidone, or a crosslinked product or copolymer containing the resin as a main component. Natural fibers such as silk, wool, cotton, hemp, and polyvinylpyrrolidone /
Polyvinyl imidazole copolymers, superabsorbent resins, pulp, rayon, paper, and various charged celluloses for cellulose ester ion exchange are also commercially available and can be effectively used. Further, a resin obtained by introducing a sulfone group, an amino group, a carboxy group, or a hydroxyl group into a resin which is originally hydrophobic can also be used. The term "hydrophobic" refers to a substance having a weight increase rate of less than 2% determined by the above-described formula 1. 400 ppm
In the following, it is preferable to use one in which mixing of sodium ions is suppressed. More preferably, it is 50 ppm or less, more preferably 10 ppm or less.

The polishing pad of the present invention may further contain a water-soluble substance. Various commercially available polyalkylene glycol, polyvinyl vinylidone, polyvinyl alcohol, polyvinyl acetate, chitosan, polyvinyl pyrrolidone, polyvinyl imidazole,
There are water-soluble polysaccharides and the like, and these polymers can be used. In addition, low molecular substances such as various inorganic salts can be mixed. When molding a polishing pad,
In the present invention, since it contains a hydrophilic filler substantially insoluble in water, the risk of urethane foaming excessively increases,
This can be avoided by utilizing the fact that the reactivity of the polyol component and the amine component is higher than the reactivity with water. Of course, the filler is used after being dried, but it is difficult to completely remove the water. Therefore, at the time of molding, voids can be formed in portions other than the filler by foaming with the water. To control the size of the voids, for example, pressurizing during molding, using an antifoaming agent (such as a silicone foam stabilizer), or introducing a functional group such as an amine highly reactive with isocyanate. Can be adjusted with.

Furthermore, when these water-soluble substances dissolve during polishing, voids are formed only on the surface of the polishing pad, and these voids increase the retention of free abrasive grains in the polishing slurry and reduce the amount of polishing dust. It is effective in removing, and consequently works to improve the polishing rate. Further, when this water-soluble substance is dissolved in the dispersion liquid of the polishing liquid, its viscosity can be changed. For example, when xanthan gum, one of the water-soluble polysaccharides, is mixed, the polishing liquid dissolves, causing the polishing liquid to have a Bingham fluid-like property, possibly suppressing the diffusion of abrasive particles in the concave portions of the uneven semiconductor wafer. Therefore, the effect of improving the flatness when polished, particularly the global flatness, can be obtained. In order to exhibit these effects, a water-soluble substance should be added in an amount of 0.
It is preferable to add from 01 wt% to 10 wt%. The effect is obtained even when the water-soluble substance is added in an amount of about 0.01% by weight, but preferably the added amount is 0.1% by weight or more and 5% by weight or less. If it exceeds 10% by weight, the properties of the polishing dispersion are changed too much, which is not preferable. If a low-molecular substance having little effect on the viscosity of the dispersion is used, a larger amount can be mixed, but it is not practical from the viewpoint of cost.

As a method of forming the polishing pad, a filler, and in some cases, inorganic fine particles and / or a water-soluble substance are preliminarily mixed, mixed with the polyurethane before curing, defoamed, placed in a mold, and subjected to hot compression molding. It can also be extruded. A method such as an injection press is also possible. Since particles and / or fibrous materials are used, the mixing can be performed efficiently, and thus the variation in the physical properties of the finished polishing pad can be reduced. If no filler is mixed, the moldability is further improved.

Specifically, it depends on the compatibility between the polyurethane and the filler, and the physical properties such as the individual heat resistance, polymerization characteristics, and viscosity, but it is easy for those skilled in the art to select the combination. As for the polishing pad of the present invention, a combination of known techniques can be used for the manufacturing method.

The hydrophilic and substantially water-insoluble filler is selected from at least one of non-woven fabric, woven fabric, knitted fabric, felt, porous membrane, sponge, film, particle, and fiber. It is preferred that it is not.
The nonwoven fabric refers to a cloth in a broad sense in which fibers are entangled, but may be distorted or have irregularities. Non-woven, woven,
Knitted and felt-like materials are also obtained from fibrous materials. The porous film or sponge shape means a film having a large porosity in a broad sense that is opened two-dimensionally and / or three-dimensionally, and the film shape means a film having substantially no holes. The term “particulate” basically refers to a sphere, but may be distorted or have irregularities. An intricately shaped shape such as so-called fumed silica can also be preferably used. Also, long fibers may be cut short. The fibrous material refers to a long and thin shape in which the ratio of the major axis to the minor axis exceeds 3.

The diameter of the fibers constituting these fibers (the maximum diameter in the case of other than spheres) is preferably 100 μm or less.
μm or less is more preferably used, and about 2 to 20 μm is preferably used. Some ultrafine fibers have a diameter of less than 2 μm, and it is convenient to use these. If the diameter is large, separation from the matrix increases, and the durability as a polishing pad tends to decrease, which is not preferable. The fibrous material may be a hollow fiber. The cross-sectional shape may be any shape proposed as a synthetic fiber such as a circle, an ellipse, or a star, or a new synthetic fiber. Porous membrane,
In the sponge-like material, the holes are connected by thin columns, and usually have a diameter of about 10 nm to about 1 mm, but the size does not matter. By using a material that occupies a void in the total volume, that is, a void having a high porosity of more than 25%, and compressing in the thickness direction to mold,
It is preferably used because it can suppress variations in the thickness direction. Further, the film-like material is suitably used for forming a layer (separation layer) for separating individual layers of the laminate. Particularly, an ultrathin film of less than 1 μm can be used in the same manner as a nonwoven fabric, woven, knitted, felt, porous membrane, or sponge sheet.

A plurality of sheet-like layers formed by mixing these fillers are laminated to form one polishing pad. For this reason, the polishing pad according to the present invention using a sheet-like material as the filler has extremely high bending strength and is unlikely to crack. By using a sheet having a large thickness, it is of course possible to form a single polishing pad. In addition, it can be combined with a sheet-like layer in which no filler is mixed. The formation of a layer having a thickness of about 1 μm per sheet and / or a thicker layer and the superposition of a plurality of layers make it easier to form a polishing pad that has high stability of polishing characteristics and that can precisely control the state of the polished surface. Become. Usually, 5 μm or more is used, and optimally 100 to 300 μm is used. The thickness and the material of each layer need not be the same, and the polishing pad can be changed by changing the resin content and / or type of the matrix resin for each layer, or by changing the thickness and / or type of the sheet material for each layer. Can be designed precisely.

For example, a polishing layer, a cushion layer portion and a separation layer portion are set as a cushion layer made of foamed polyurethane, a rubber sheet, or the like, and a plurality of such layers are laminated. If you stick it
It is possible to provide a long-life polishing pad that does not need to be replaced for many times as long as the conventional polishing pad. By providing a separation layer, the polishing layer portion can be polished with the virgin surface formed by dressing without contacting the polishing liquid or the polishing dispersion liquid infiltrated from the polishing surface, so that extremely high polishing stability Can be obtained. Also, when the interlayer insulating film and metal polishing are required alternately, the order is determined so that the most suitable for the application, for example, use a very hard layer for polishing the interlayer insulating film and use a soft layer for metal polishing. You can also. As described above, according to the present invention, it is possible to improve the throughput for manufacturing and to reduce the total cost.

As described above, the bending elastic modulus of the polishing pad can be made larger than that of the conventional polishing pad. In order to improve the flattening characteristics, it is preferably 0.5 GPa or more, more preferably 2 GPa or more. In the polishing pad of the present invention, since there is no problem of dust adhesion and scratch damage, a larger 5 GPa or more and 20 GPa or more.
a or less is more preferable. However, if it is too large, it becomes difficult to mount the polishing pad.

It is preferable that grooves or holes are provided on the polishing pad surface for the purpose of promoting the supply of the polishing slurry to the polishing surface and discharging the slurry therefrom. As the shape of the groove, various shapes such as concentric circles, spirals, radiation, and grids can be adopted. As the cross-sectional shape of the groove, a shape such as a square, a triangle, and a semicircle can be adopted. The groove depth can be selected from 0.1 mm to the thickness of the polishing layer, the groove width can be selected from 0.1 to 5 mm, and the groove pitch can be selected from 0.2 to 100 mm. The holes may or may not penetrate the polishing layer. The diameter of the holes can be selected in the range of 0.2-5 mm. The pitch of the holes is 1 to 100 mm
You can choose from a range. These shapes may be sufficient to supply the polishing liquid to the polishing surface successfully, to enhance the holding ability of the polishing liquid, and to satisfactorily discharge and / or promote the polishing liquid from the polishing liquid. The shape of the polishing pad itself can be processed into various shapes such as a disk shape, a donut shape, and a belt shape. Thicknesses of about 0.1 mm to about 50 mm or more can also be manufactured. As for the diameter when processed into a disk shape or a donut shape, the diameter is manufactured from about 1/5 to about 5 times based on the size of the object to be polished, but if it is too large, the processing efficiency is reduced. Therefore, it is not preferable.

The polishing pad obtained in the present invention can be used as a composite polishing pad by laminating it with a cushion sheet having cushioning properties. A semiconductor substrate has slightly larger undulations apart from local irregularities, and a polishing sheet is often polished with a cushion sheet below a hard polishing pad (on the polishing platen side) as a layer for absorbing the undulations. As the cushion sheet, a urethane foam-based or rubber-based one can be used in combination.

When the polishing pad of the present invention is used, for example, in the manufacture of a semiconductor chip, firstly, it is employed for polishing a semiconductor wafer (bare wafer and / or wafer with an oxide film) before being subjected to unevenness processing. Has fine irregularities, ie, waviness and nanotop
It is preferable to eliminate surface defects expressed as “ology” or the like. Thereafter, a surface pattern is processed by lithography or the like, and CMP polishing is performed. By performing this process using the polishing apparatus according to the present invention, processing with extremely high flatness becomes possible, and it is possible to easily meet the demands for multilayered semiconductor chips, high integration, and fine wiring. become.

The optical member used for the flat panel display is very thin itself, so that surface irregularities and adhesion of foreign matter have a great effect on the image quality of the screen display of the flat panel display. Is required. Optical members used in such flat panel displays, such as color filters for liquid crystal displays and PDP back plates for plasma displays, require chemical treatment to flatten surface irregularities and remove foreign substances adhering to the surface. A method of polishing the entire surface by mechanical polishing has been performed.

The polishing pad of the present invention has a polishing pad content of 400 ppm.
In the following, it is preferable to use one in which mixing of sodium ions is suppressed. More preferably, it is 50 ppm or less, more preferably 10 ppm or less.

[0034]

EXAMPLES The present invention will be described below with reference to examples. The evaluation of the flexural modulus, the D hardness, the amount of dust attached, the oxide film polishing rate, the flattening characteristics, and the dishing was performed as follows.

(Measurement of bending elastic modulus)
Length of 1.0 mm to 1.5 mm, length of 1 x 8.5 cm
A rectangular test piece was prepared. For this test piece, the ORI
ENTEC's material testing machine (Tensilon RTM-10
0) and the flexural modulus of elasticity according to JIS-7203.
A measurement was made. The flexural modulus was calculated according to the following equation.
It is. Flexural modulus = ｛(distance between supporting points)^Three× (load-deflection curve
Load at any point on the first straight line (kg
f))｝ / ｛4 × (width of test piece) × (thickness of test piece) ^Three
× Deflection under load F｝

(Measurement of D hardness) Thickness 1.0 mm to 1.5
Samples in the range of mm (size is 1cm square or more)
Is placed on a plane having a surface hardness of D hardness 90 or more,
Durometer type D (actually manufactured by Kobunshi Keiki Co., Ltd.) based on JIS standard (hardness test) K6253
Using an Asker D-type hardness meter "), five points were measured, and the average value was defined as D hardness. The measurement was performed at room temperature (25 ° C.).

(Measurement of Dust Adhesion Amount) Thickness 1.2 mm,
A circular polishing pad having a diameter of 38 cm was prepared, and the surface was subjected to so-called XY groove processing (grid-like groove processing) having a width of 2.0 mm, a depth of 0.5 mm, and a pitch of 15 mm. This pad is polished with a polishing machine (Lap Master SFT, "L / M-
15E ″) as a cushion layer, a Suba400 manufactured by Rodale, and a double-sided adhesive tape (3M
"442J"). Conditioner (“CMP-M”, diameter 1) of Asahi Diamond Industry Co., Ltd.
4.2cm), pressing pressure 0.04MPa, platen rotation speed 25rpm, conditioner rotation speed 25rpm
m, the polishing pad was conditioned for 5 minutes while supplying pure water at 10 ml / min. The polishing pad was washed for 2 minutes while flowing pure water at 100 ml / min through the polishing machine, and then the wafer with an oxide film (4
Inch dummy wafer CZP type, Shin-Etsu Chemical Co., Ltd.) was set on a polishing machine, and a slurry dispersion liquid (“SC-1”) manufactured by Cabot Co., Ltd. with the concentration described in the instruction manual was 100 ml / min.
Pressing pressure 0.04 while supplying on the polishing pad with
Polishing was performed for 5 minutes by rotating in the same direction at a rotational speed of 45 rpm for the platen and a rotational speed of 45 rpm for the conditioner. The surface of the wafer was not dried, and the surface of the wafer was washed with a polyvinyl alcohol sponge while being immediately sprayed with pure water, and dried by blowing dry compressed air. After that, wafer surface dust inspection equipment (Topcon Co., Ltd., "WM-
3 ″) was used to measure the number of surface dusts having a diameter of 0.5 μm or more. In this test method, a value of 400 or less was acceptable without causing any problem in semiconductor production. The number of scratches on the surface was counted with a Keyence digital microscope (VH6300) equipped with an automatic XY stage.

(Measurement of Oxide Film Polishing Rate) The thickness of the oxide film on the surface of a wafer (4-inch dummy wafer CZP type, Shin-Etsu Chemical Co., Ltd.) was previously determined by "Lambda Ace" (VM-2000) manufactured by Dainippon Screen Co., Ltd. 196 points determined by using are measured. Polishing machine (Lap Master SF
Polishing pad to be tested with double-sided adhesive tape (3M, "442J"), with Rodale's "Suba400" applied as a cushion layer to the surface plate of "L / M-15E", manufactured by T. Was stuck. Asahi Diamond Industry Co., Ltd.
Conditioner ("CMP-M", diameter 14.2c)
m), the polishing pad was rotated in the same direction at a pressing pressure of 0.04 MPa, a platen rotation speed of 25 rpm, and a conditioner rotation speed of 25 rpm, and the polishing pad was conditioned for 5 minutes while supplying pure water at 10 ml / min. The polishing pad was washed for 2 minutes while flowing 100 ml / min of pure water through the polishing machine. Then, the wafer with the oxide film whose oxide film thickness had been measured was set in the polishing machine, and the concentration described in the instruction manual was used by Cabot Corporation. Add the slurry dispersion (“SC-1”) to 1
While supplying onto the polishing pad at 00 ml / min, the plate was rotated in the same direction at a pressing pressure of 0.04 MPa, a platen rotation speed of 45 rpm, and a conditioner rotation speed of 45 rpm.
Polishing was performed for a minute. The surface of the wafer was not dried, and the surface of the wafer was washed with a polyvinyl alcohol sponge while being immediately sprayed with pure water, and dried by blowing dry compressed air. The thickness of the oxide film on the wafer surface after the polishing is determined by "Lambda Ace" (VM-20, manufactured by Dainippon Screen Co., Ltd.).
196 points determined by using (00), the polishing rate at each point was calculated, and the average value was taken as the oxide film polishing rate.

(Evaluation of Flattening Characteristics) First, a test wafer for evaluating a global step was prepared in the following procedure. Test wafer for global level difference evaluation: A 10 mm square die is arranged on a 4-inch silicon wafer with an oxide film (oxide film thickness: 2 μm). Perform a mask exposure using a photoresist, and RIE to 20 μm in a 10 mm square die.
A line with a width and height of 0.7 μm and a space of 230 μm are arranged on the left half in a line and space, and
A line having a width and a height of 0.7 μm is arranged in a line and space on the right half in a space of 20 μ.

Next, a circular polishing layer having a diameter of 38 cm was formed, and a surface having a width of 2.0 mm, a depth of 0.5 mm and a pitch of 15 mm was formed.
mm XY groove processing (grid-like groove processing). A polishing machine (Lapmaster SF)
As a cushion layer, "Suba400" manufactured by Rodale was pasted on a surface plate of L / M-15E manufactured by T Company, and a double-sided adhesive tape ("442J" manufactured by 3M) was pasted thereon. Using a conditioner (“CMP-M”, diameter 14.2 cm) of Asahi Diamond Industrial Co., Ltd., rotate in the same direction at a pressing pressure of 0.04 MPa, a platen rotation speed of 25 rpm, and a conditioner rotation speed of 25 rpm, and pure water of 10 ml. The polishing pad was conditioned for 5 minutes while supplying at a rate of / min. 100m of pure water in polishing machine
The polishing pad was washed for 2 minutes while flowing at a rate of 1 / min. Then, a test wafer for evaluating a global level difference was set on the polishing machine, and a slurry (“SC-1”) manufactured by Cabot Co., having the concentration described in the instruction manual, at 100 ml / min While supplying on the polishing pad with a pressure of 0.04 MPa and a platen rotation speed of 45 rpm (linear velocity at the center of the wafer is 3000
(Cm / min)), the sample stage holding the semiconductor wafer was rotated at 45 rpm.
It was rotated in the same direction at rpm and polished for a predetermined time.
The surface of the semiconductor wafer was not dried, and the surface of the wafer was washed with a polyvinyl alcohol sponge while being immediately sprayed with pure water, and dried by blowing dry compressed air. The oxide film thickness of the 20 μm line and the 230 μ line in the center 10 mm die of the test wafer for global level difference evaluation was changed to a lambda ace (“VM-200” manufactured by Dainippon Screen Co., Ltd.).
0 ″), and the difference between the thicknesses was evaluated as a global step.
Other shapes were performed in the same procedure as above. 20μ
A global step between the m-width wiring region and the 230 μm-width wiring region was judged to be acceptable if the polishing time was 5 minutes and 450 nm or less.

(Evaluation of dishing) Tungsten wiring dishing evaluation test wafer: 100 μm on 4-inch silicon wafer with oxide film (oxide film thickness: 2 μm)
Grooves having a width and a depth of 0.7 μm are formed at intervals of 100 μm. A tungsten film having a thickness of 2 μm was formed thereon by sputtering to prepare a test wafer for evaluating dishing of tungsten wiring.

Next, a circular polishing layer having a diameter of 38 cm was formed, and a surface having a width of 2.0 mm, a depth of 0.5 mm and a pitch of 15 mm was formed.
mm XY groove processing (grid-like groove processing). A polishing machine (Lapmaster SF)
As a cushion layer, "Suba400" manufactured by Rodale was pasted on a surface plate of L / M-15E manufactured by T Company, and a double-sided adhesive tape ("442J" manufactured by 3M) was pasted thereon. Using a conditioner (“CMP-M”, diameter 14.2 cm) of Asahi Diamond Industrial Co., Ltd., rotate in the same direction at a pressing pressure of 0.04 MPa, a platen rotation speed of 25 rpm, and a conditioner rotation speed of 25 rpm, and pure water of 10 ml. The polishing pad was conditioned for 5 minutes while supplying at a rate of / min. 100m of pure water in polishing machine
The polishing pad was washed for 2 minutes while flowing at 1 / min. Then, a test wafer for evaluating tungsten wiring dishing was set on the polishing machine, and a slurry manufactured by Cabot Corporation (“SEMI-SPERSE W-A40”) having the concentration described in the instruction manual was used.
0 ”) and an oxidizing agent manufactured by Cabot (“ SEMI-SPER
SEFE-400 ") at a pressure of 0.04 MPa and a platen rotation speed of 45 rpm while supplying a slurry solution mixed at 1: 1 onto the polishing pad at 100 ml / min.
m (linear velocity at the center of the wafer is 3000 (cm /
Min)), the semiconductor wafer holding sample stage was rotated in the same direction at a rotation speed of 45 rpm, and polishing was performed for 2 minutes. The surface of the semiconductor wafer was not dried, and the surface of the wafer was washed with a polyvinyl alcohol sponge while being immediately sprayed with pure water, and dried by blowing dry compressed air. The dishing state of the tungsten surface was measured with an ultra-depth shape measuring microscope “VK-8500” manufactured by Keyence Corporation. In addition, about the surface processing form of a polishing layer, the thing of another shape was performed in the same procedure as the above. The center depth of the tungsten wiring was measured.

Example 1 Two-component polyurethane resin C-4403 (manufactured by Nippon Polyurethane Co., Ltd.) 62% by weight and N-4276 (manufactured by Nippon Polyurethane Co., Ltd.) 38% by weight were kneaded and formed into a 40 cm square mold. Then, the resultant was vacuum-degassed and formed into a thickness of 1.2 mm to form a polishing pad.

Example 2 51% by weight of a two-component polyurethane resin C-4421 (manufactured by Nippon Polyurethane Co., Ltd.) and 49% by weight of N-4276 (manufactured by Nippon Polyurethane Co., Ltd.) were kneaded and formed into a 40 cm square mold. Then, the resultant was vacuum-degassed and formed into a thickness of 1.2 mm to form a polishing pad.

Example 3 Two-component polyurethane resin KC-362 (manufactured by Nippon Polyurethane Co., Ltd.) 51% by weight and N-4276 (manufactured by Nippon Polyurethane Co., Ltd.) 49% by weight were kneaded, and the mixture was molded into a 40 cm square mold. Then, the resultant was vacuum-degassed and formed into a thickness of 1.2 mm to form a polishing pad.

Example 4 53% by weight of a two-component polyurethane resin C-4421 (manufactured by Nippon Polyurethane Co., Ltd.) and 47% by weight of KN-569 (manufactured by Nippon Polyurethane Co., Ltd.) were kneaded and formed into a 40 cm square mold. Then, the resultant was vacuum-degassed and formed into a thickness of 1.2 mm to form a polishing pad.

Examples 5 to 7 The urethanes of Examples 2 to 4 were kneaded, respectively, to a thickness of 0.1 kPa.
Impregnated in 18mm kraft paper (official moisture content 10%)
Six sheets were stacked and placed in a mold of 40 cm square, vacuum-degassed, and then molded to a thickness of 1.2 mm to form a polishing pad. Each cross section was observed with an optical microscope, but no void was found in the kraft paper.

Examples 8 to 10 Each of the urethanes of Examples 2 to 4 was kneaded to a thickness of 0.1 kPa.
Impregnated in 18mm kraft paper (official moisture content 10%)
Six sheets were placed in a mold of 40 cm square and formed into a thickness of 1.2 mm to form a polishing pad. Each cross section was observed with an optical microscope, but no void was found in the kraft paper. Some foaming was observed in each of the polyurethane matrices.

Example 11 A polishing pad was prepared using a resin mixed with 3% by weight of silica particles having a pore size of 1 μm and dried sufficiently in Example 7. When the cross section was observed with an optical microscope, no void was found in the kraft paper.

Example 12 A polishing pad was prepared using a resin mixed with 15% by weight of silica particles having a pore size of 1 μm and dried sufficiently in Example 7. When the cross section was observed with an optical microscope, no void was found in the kraft paper.

Example 13 In Example 11, a polishing resin plate was prepared by further adding 0.8 wt% of xanthan gum as a hydrophilic water-soluble resin.
When the cross section was observed with an optical microscope, no void was found in the kraft paper.

Example 14 In Example 12, 0.8 wt% of xanthan gum was further added as a hydrophilic water-soluble resin to prepare a polished resin plate.
When the cross section was observed with an optical microscope, no void was found in the kraft paper.

Example 15 In Example 11, a polished resin plate was produced without performing vacuum degassing. When the cross section was observed with an optical microscope, no void was found in the kraft paper. Voids were found in the polyurethane matrix.

Example 16 In Example 5, a polished resin plate was produced without performing vacuum defoaming.
When the cross section was observed with an optical microscope, voids were found in the kraft paper and in the polyurethane matrix.

Example 17 A two-component polyurethane resin C-4421 (manufactured by Nippon Polyurethane Co., Ltd.) 51% by weight and N-4276 (manufactured by Nippon Polyurethane Co., Ltd.) 49% by weight were kneaded, and a nylon nonwoven fabric (having a basis weight of 300 g / (m ² , official moisture content: 4.5%), placed in a 40 cm square mold, degassed under vacuum, and formed into a 1.2 mm thick polishing pad. No void was observed in the nylon nonwoven fabric.

Example 18 A two-component polyurethane resin KC-384 (manufactured by Nippon Polyurethane Co., Ltd.) of 71% by weight and KN-590 (manufactured by Nippon Polyurethane Co., Ltd.) of 29% by weight were kneaded to make up to 75% by weight. Was mixed with 25% by weight of powder filter paper (KC Floc, 400 mesh, Nippon Paper Industries Co., Ltd., 400 mesh) vacuum-dried at 80 ° C. for 3 hours, defoamed, sandwiched between polyethylene plates of 50 cm width, and molded to a thickness of 1.2 mm A polishing pad was made.
Voids were found in the polyurethane matrix.

Example 19 Two-component polyurethane resin KC-384 (manufactured by Nippon Polyurethane Co., Ltd.) of 71% by weight and KN-590 (manufactured by Nippon Polyurethane Co., Ltd.) of 29% by weight were kneaded to make 75% by weight. Mixed with 15% by weight of powder filter paper (KC Floc, 400 mesh, Nippon Paper Industries Co., Ltd., 400 mesh) vacuum-dried at 80 ° C. for 3 hours, defoamed, sandwiched between 50 cm wide polyethylene plates, and molded to a thickness of 1.2 mm. A polishing pad was made.
Voids were found in the polyurethane matrix.

Example 20 In Example 19, 0.8 wt% of xanthan gum was further added as a hydrophilic water-soluble resin to prepare a polished resin plate. Voids were found in the polyurethane matrix.

Comparative Example 1 A polishing pad made of commercially available urethane foam (Rodale, Inc.)
IC-1000) was processed to a diameter of 38 cm to prepare a polishing pad.

Comparative Example 2 A polyurethane film (1 mm
Was processed to a diameter of 38 cm to prepare a polishing pad.

Comparative Example 3 70% by weight of a two-component polyurethane resin KC-380 (manufactured by Nippon Polyurethane Co., Ltd.) and 30% by weight of KN-584 (manufactured by Nippon Polyurethane Co., Ltd.) were kneaded to become 75% by weight. Filter paper (KC Floc, 400 mesh, Nippon Paper Industries Co., Ltd., 400 mesh) 5% by weight
After defoaming, the mixture was sandwiched between polyethylene plates having a width of 50 cm and molded to a thickness of 1.2 mm to prepare a polishing pad. Voids were found in the polyurethane matrix.

[0062]

[Table 1]

[0063]

According to the present invention, dust adhesion to the surface of the object to be polished can be reduced.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) B24D 3/32 B24D 3/32 C08J 5/14 CFF C08J 5/14 CFF C08K 3/00 C08K 3/00 7 / 02 7/02 C08L 75/04 C08L 75/04 101/00 101/00 101/14 101/14 H01L 21/304 622 H01L 21/304 622F F term (reference) 3C058 AA09 CB02 CB10 DA12 DA17 3C063 AA10 BA22 BB01 BC03 BD01 BD02 EE10 4F071 AA53 AE13 AE17 AH19 DA09 DA17 DA22 4J002 AB00Y AB01X AB04W AB05X AB05Y AD00X AH00X BE02X BE02Y BE03X BF02X BF02Y BF02Y BG01X BJ00X BJ00Y CH02Y CK02DE096 CK02W 006

Claims (11)

[Claims] 1. A polishing pad comprising mainly a urethane resin having a surface D hardness of 65 or more. 2. The polishing pad according to claim 1, wherein the surface D hardness is 70 or more. 3. The polishing pad according to claim 1, further comprising a hydrophilic filler substantially insoluble in water. 4. The polishing pad according to claim 1, wherein the polishing pad further has voids apart from the particles formed of the fibrous material and / or the composite thereof. 5. The polishing pad according to claim 1, further comprising inorganic fine particles. 6. The polishing pad according to claim 1, further comprising a water-soluble substance. 7. The water-soluble substance is contained in an amount of 0.01 wt% to 10 w%.
The polishing pad according to claim 6, wherein the polishing pad contains t%. 8. The polishing pad according to claim 1, wherein a water absorption rate is 2.0 wt% or more. 9. A polishing apparatus using the polishing pad according to claim 1. Description: 10. A polishing method using the polishing pad according to claim 1. Description: 11. A method for manufacturing a semiconductor wafer or a semiconductor chip, wherein the method is performed by using the polishing pad according to claim 1.