WO2015101316A1

WO2015101316A1 - Polishing pad and preparation method thereof

Info

Publication number: WO2015101316A1
Application number: PCT/CN2014/095804
Authority: WO
Inventors: 张莉娟
Original assignee: 成都时代立夫科技有限公司
Priority date: 2014-01-06
Filing date: 2014-12-31
Publication date: 2015-07-09
Also published as: CN103753382B; CN103753382A

Abstract

A polishing pad and preparation method thereof, the polishing pad comprising more than two grooves (5), a polyurethane base material (1), a polyurethane fiber substrate (2), a polyurethane-ethylene adhesive PSA-A layer (3) and PSA-B layer (4); the grooves (5) are uniformly arranged on one surface of the polyurethane base material (1); the other surface of the polyurethane base material (1) adheres to one surface of the polyurethane fiber substrate (2) via the polyurethane-ethylene adhesive PSA-A layer (3); the other surface of the polyurethane fiber substrate (2) is connected to the polyurethane-ethylene adhesive PSA-B layer (4); and ultra-short polyester fiber and ultra-short aramid fiber are added to the polyurethane base material (1). The polishing pad exhibits high polishing speed, evenness and long service life in chemical mechanical polishing.

Description

Polishing pad and preparation method thereof

Technical field

The invention relates to a polishing pad and a preparation method thereof, in particular to a polishing pad with a fiber-filled solid polyurethane and a preparation method thereof, and belongs to the field of precision polishing of a semiconductor chip, polishing of an LED substrate, and polishing of sapphire.

Background technique

The semiconductor industry is at the heart of the modern electronics industry, and the semiconductor industry is based on the silicon materials industry. Although a variety of new semiconductor materials are emerging, more than 90% of semiconductor devices and circuits, especially ultra-large scale integrated circuits (ULSI), are fabricated on high-purity, high-quality silicon single crystal polishing wafers and epitaxial wafers. At present, VLSI manufacturing technology has been developed to the 0.25nm and 300mm eras. With the further miniaturization of the feature line width, higher requirements are placed on the degree of planarization of the silicon wafer surface. CMP is recognized as the best material global planarization method in the ULSI stage, which can obtain a perfect surface. Moreover, a higher polishing rate can be obtained, which has basically replaced the conventional heat flow method, the rotary glass method, the etch back method, the electron surround resonance method and the like.

The chemical mechanical polishing pad plays an important role in the whole polishing process. In addition to the effective uniform distribution of the polishing liquid, it can also provide a new supplementary polishing liquid, and can smoothly carry out the polishing liquid and product after the reaction. discharge. Hardness is an important parameter to characterize the performance of the polishing pad. A hard polishing pad can be used to obtain better overall and local flatness, while a soft polishing pad can achieve better surface quality and activity. The porosity and surface roughness of the polishing pad are important parameters affecting the transmission efficiency of the polishing liquid. As the use time increases, the surface of the polishing pad will become smooth, the pores will be blocked and reduced, and the polishing speed will decrease. It must be corrected to restore it as much as possible. At the same time, the effect of pressure and other mechanical forces in chemical mechanical polishing, after polishing for a certain period of time, the polishing pad is mechanically twisted and deformed, the effect of the polishing effect caused by the problem and the shortening of the service life of the polishing pad, Rohma In the chemical mechanical polishing pad invented in the early 2000s, the company added other chemicals to alleviate the negative effects caused by polishing distortion. Because the chemical is elastic, the pressure resistance is above 30Mpa, and it has good mechanical strength. Mechanical distortion is highly resilient. However, the substance is extremely light in weight. Once the package is opened, it is easy to fly in the process of adding. When operating, it is necessary to wear protective glasses, protective tools such as hand protection and protective mask, and it is not easy to stir. In addition, the substance manufacturer is single and must rely on foreign imports. In order to solve this problem, mass production is facilitated, and the service life and mechanical properties of the polishing pad are improved.

Summary of the invention

The technical problem to be solved by the present invention is to provide a polishing pad which can be mass-produced, has improved service life and mechanical properties, and a preparation method thereof.

The technical solution of the present invention to solve the above technical problems is as follows: a polishing pad comprising two or more grooves, a polyurethane substrate, a polyurethane fiber substrate, a polyurethane rubber PSA-A layer and a polyurethane vinyl PSA-B layer. The groove is evenly arranged on one surface of the polyurethane substrate, and the other surface is bonded to a surface of the polyurethane fiber substrate through the polyurethane vinyl PSA-A layer, and the polyurethane fiber substrate is further A surface is attached to the layer of polyurethane vinyl PSA-B.

The invention has the beneficial effects that: the groove serves to transport the new polishing liquid, discharge the old polishing liquid and the debris generated after the grinding; the polyurethane substrate acts as a polishing; the polyurethane fiber substrate mainly serves as a buffering and heat dissipating effect; Vinyl rubber PSA-A layer, used as the upper layer substrate and substrate bonding; polyurethane vinyl adhesive PSA-B layer, polishing pad and polishing platform Bonding effect.

Based on the above technical solutions, the present invention can also be improved as follows.

Further, the polyurethane substrate, the polyurethane fiber substrate, the urethane vinyl adhesive PSA-A layer and the urethane vinyl adhesive PSA-B layer are all circular in shape, and the radius of the polyurethane substrate is smaller than that of the polyurethane fiber substrate. The radius, the central region thereof forms a grooveless region, the grooveless region being circular in shape and having the same center as the polyurethane fiber substrate.

Further, the polyurethane fiber substrate has a diameter of 350 mm to 1100 mm.

Further, the groove-free area is provided with a coded mark area, the groove-free area has a diameter of 10 mm to 60 mm, and the coded mark area and the groove-free area have the same center, and the diameter thereof is 2 mm. ~20mm.

Further, the groove has a depth of 0.5 mm to 1.5 mm and a width of 0.2 mm to 1.0 mm.

Further, the polyurethane substrate has a thickness of 1.1 mm to 3.0 mm; the polyurethane fiber substrate has a thickness of 0.8 mm to 2.2 mm; and the polyurethane vinyl Glue PSA-A layer has a thickness of 0.8 mm to 2.0 mm; The thickness of the polyurethane vinyl Glue PSA-B layer is from 0.8 mm to 2.0 mm.

Another technical solution to solve the above technical problem is as follows: a method for preparing a polishing pad, comprising the following steps:

1) heating the prepolymer reactant to 75 ° C, heating the MOCA to 115 ° C, and then performing the gel at a temperature of 75 ° C to 115 ° C for a gel time of about 5 to 15 minutes, wherein the prepolymerization The weight ratio of the bulk reactant to the MOCA is 3.58:1;

2) adding 1% to 8% by weight of ultra-short polyester fiber or ultra-short aramid fiber to the prepolymer reactant, and pre-polymerizing the reactant with a stirring tank at a rotation speed of 1500 rpm to 3500 rpm MOCA is thoroughly stirred and mixed to obtain a mixture A;

3) The mixture A is placed in a centrifuge at 92 ° C to 110 ° C for high temperature gelation, gel for 30 minutes to 90 minutes to obtain a polyurethane sheet after gelation;

4) transferring the gelled polyurethane sheet obtained in the step 3) to a vulcanization oven, and vulcanizing at a temperature of 100 ° C to 120 ° C for 10 to 17 hours to obtain a vulcanized polyurethane sheet;

5) The vulcanized polyurethane sheet obtained in the step 4) is used as a polyurethane substrate, the polyurethane fiber is made into a polyurethane fiber substrate, and the polyurethane rubber PSA-A is bonded as a backing phase, and then the polyurethane fiber lining is used. The other surface of the bottom is further coated with a layer of polyurethane vinyl PSA-B, which is then stamped and formed. After molding, more than two grooves are dug on the surface of the polyurethane substrate to obtain the polishing pad.

Further, the preparation steps of the ultra-short polyester fiber or the ultra-short aramid fiber are as follows: esterification or transesterification reaction and polycondensation reaction using terephthalic acid or dimethyl terephthalate and ethylene glycol as raw materials. Obtaining polyethylene terephthalate, and then spinning and post-treating to form the ultra-short polyester fiber or ultra-short aramid fiber; wherein the ultra-short polyester fiber or ultra-short aramid fiber is in diameter 0.1 μm to 15 μm, uniformly arranged without polymerized powdery fibers.

Further, the prepolymer reactant is an isocyanate-terminated reaction product formed by the reaction of a prepolymer polyol and a polyfunctional aromatic isocyanate, the isocyanate-terminated reaction product comprising 7.5% to 9.9 weight percent unreacted NCO.

Further, the prepolymer polyol includes any one of polytetramethylene ether glycol, polypropylene ether glycol, ethylene glycol diacetate or butylene glycol diacrylate.

Among them, the polytetramethylene ether glycol (PTMEG) is commercially available from DuPont Terathane 2900, 2000, 1800, 1400, 1600, 650, 250 series.

Polypropylene ether glycol (PPG) is available from BASF's PolyTHF 650, 1000, 1800, 2000 series and Lyondell Polymeg2000, 1000, 1500, 650 series.

The polyfunctional aromatic isocyanate has one or more aromatic rings and one or more isocyanate groups attached directly or indirectly to one or different aromatic rings.

Including 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4'4-diphenylmethane diisocyanate, benzene-1,5-diisocyanate, dimethylamine diisocyanate, p-phenylene diisocyanate or Any one of xylene diisocyanate and the like.

The polyurethane substrate of the invention is added with ultra-short polyester fiber or ultra-short aramid fiber. Polyester is an important variety in synthetic fiber and is the trade name of polyester fiber in China. Polyester fiber has high strength, good elasticity, good wear resistance, acid and alkali resistance, moisture absorption, and deformation, which are suitable for chemical mechanical polishing pad. The melting point of polyester first is usually 255 ° C to 260 ° C. Since the isocyanate-terminated polyurethane prepolymer has a temperature below 150 ° C in the whole process of synthesizing chemical mechanical polishing pad, it can be used safely in production.

Polyester fiber not only has unique physical and chemical properties, but also has a suitable specific gravity, which is easy to operate and add. It has no adverse effects on people and the surrounding environment during operation. At the same time, through the plasticity study of polyurethane materials, adding polyurethane with proper proportion of polyester fiber can greatly increase the elasticity of polyurethane itself. The improvement of elasticity enhances the polishing pad itself resisting the deformation ability caused by mechanical extrusion, and the self-repairing ability of the material. Enhanced. The polishing data proves that the global flatness of the polishing pad with ultra-short polyester fiber added in the chemical mechanical polishing is significantly enhanced compared with the global flatness of the polishing pad without the addition of polyester.

Polyurethane polishing pad with polyester fiber added, because it has no expansion during casting process, can also be called solid hard polyurethane polishing pad, which makes the chemical mechanical polishing pad have the hardness and elasticity and mechanical properties required for trial and semiconductor chip polishing in semiconductor chips. Tungsten wire polishing, oxide layer polishing, and copper polishing show good polishing rate and flatness. A higher quality surface smoothness and cleanliness.

Due to the high strength and high wear resistance of polyester fiber itself, the polyurethane polishing pad with polyester fiber has a significantly higher service life than the polyurethane polishing pad without added fiber. The test data shows that the polyurethane polishing with polyester fiber is added. The life of the pad is up to 70 to 75 hours in the oxide layer, which is 1.7 times the service life of the Dow IC1010 polishing pad on the market. The polyurethane polishing pad with polyester fiber has a service life of up to 40 in the metal layer. Up to 45 hours is 2.2 times the life of the typical Dow IC1000 polishing pad on the market today.

The polishing process parameters are as follows:

DRAWINGS

Figure 1 is a plan top view of the polishing pad of the present invention;

Figure 2 is a half cross-sectional view of the polishing pad of the present invention;

3 is a diagram showing the service life of the polishing pad of the present invention in an 8-inch chip oxide layer;

4 is a diagram showing the service life of the polishing pad of the present invention in an 8-inch chip metal tungsten wire layer;

In the drawings, the list of parts represented by each label is as follows:

1, polyurethane substrate, 2, polyurethane fiber substrate, 3, polyurethane vinyl PSA-A Layer, 4, polyurethane vinyl PSA-B layer, 5, groove, 6, no groove area, 7, code identification area.

detailed description

The principles and features of the present invention are described in the following with reference to the accompanying drawings.

A polishing pad, as shown in FIG. 1 and FIG. 2, comprises two or more grooves 5, a polyurethane substrate 1, a polyurethane fiber substrate 2, a polyurethane rubber PSA-A layer 3, and a polyurethane rubber PSA-B layer. 4. The groove 5 is evenly arranged on one surface of the polyurethane substrate 1, and the other surface is bonded to a surface of the polyurethane fiber substrate 2 through the urethane vinyl PSA-A layer 3. The other surface of the polyurethane fiber substrate 2 is joined to the polyurethane vinyl PSA-B layer 4.

The polyurethane substrate 1, the polyurethane fiber substrate 2, the urethane vinyl adhesive PSA-A layer 3, and the urethane vinyl adhesive PSA-B layer 4 are all circular in shape, and the polyurethane substrate 1 has a radius smaller than the polyurethane fiber. The radius of the substrate 2, the central portion thereof forms a grooveless region 6, which is circular in shape and has the same center as the polyurethane fiber substrate 2.

The polyurethane fiber substrate 2 has a diameter of 350 mm to 1100 mm. The grooveless area 6 is provided with a coded identification area 7 having a diameter of 10 mm to 60 mm, and the coded identification area 7 and the grooveless area 6 have the same center and diameter. It is 2mm to 20mm.

The groove 5 has a depth of 0.5 mm to 1.5 mm and a width of 0.2 mm to 1.0 mm. The polyurethane substrate 1 has a thickness of 1.1 mm to 3.0 mm; the polyurethane fiber substrate 2 has a thickness of 0.8 mm to 2.2 mm; and the polyurethane vinyl adhesive PSA-A layer 3 has a thickness of 0.8 mm to 2.0 mm; The thickness of the polyurethane vinyl PSA-B layer 4 is 0.8mm to 2.0mm.

A method for preparing a polishing pad, comprising the following steps,

The preparation steps of the ultra-short polyester fiber or the ultra-short aramid fiber are as follows: esterification or transesterification reaction and polycondensation reaction using terephthalic acid or dimethyl terephthalate and ethylene glycol as raw materials to obtain a poly The ultra-short polyester fiber or the ultra-short aramid fiber is prepared by spinning and post-treating ethylene terephthalate; wherein the ultra-short polyester fiber or ultra-short aramid fiber has a diameter of 0.1 μm ～15 μm, uniformly arranged without polymerized powdery fibers.

The prepolymer reactant is a prepolymer polyol and a polyfunctional aromatic isocyanate The isocyanate-terminated reaction product should be formed, the isocyanate-terminated reaction product comprising 7.5% to 9.9 weight percent unreacted NCO.

The prepolymer polyol includes any one of polytetramethylene ether glycol, polypropylene ether glycol, ethylene glycol diacetate or butylene glycol diacrylate;

The polyfunctional aromatic isocyanate comprises 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4'4-diphenylmethane diisocyanate, benzene-1,5-diisocyanate, dimethylamine diisocyanate Any one of p-phenylene diisocyanate or xylene diisocyanate.

Example 1 Test Data and Results of Oxide Polishing

1. Polishing mechanical parameter setting

Polishing results:

Polishing rate and polishing flatness:

From the above test results and Figure 3, the overall polishing rate of the polyester-polished polyurethane polishing pad can be improved by fine-tuning the polishing pressure, and the polishing flatness rate is very stable and maintained at about 2%. This flatness ratio is generally less than or equal to the current market. The flatness value of 7% is greatly reduced. In chemical mechanical polishing, the lower the global polishing flatness, the better the overall polishing effect and the higher the yield of the chip.

Example 2 Test Data and Results of Metal Layer Polishing

Polishing results:

Polishing rate and polishing flatness:

It can be seen from the above test results and Fig. 4 that no matter how the polishing test parameters are adjusted, the polishing pad is increased or decreased with the change of the polishing parameters, and the polyurethane polishing pad with 0.5% to 7% of the polyester fiber powder is always expressed. Excellent and very smooth global flatness (NU%). And polishing life is greatly increased.

Example 3 AF test results of polishing surface flatness:

The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalents, improvements, etc., which are within the spirit and scope of the present invention, should be included in the protection of the present invention. Within the scope.

Claims

A polishing pad comprising two or more grooves, a polyurethane substrate, a polyurethane fiber substrate, a urethane vinyl PSA-A layer, and a urethane vinyl PSA-B layer, one surface of the polyurethane substrate The groove is uniformly arranged on the other surface, and the other surface is bonded to a surface of the polyurethane fiber substrate through the urethane vinyl PSA-A layer, and the other surface of the polyurethane fiber substrate and the polyurethane ethylene The glue PSA-B layers are connected.
The polishing pad according to claim 1, wherein the polyurethane substrate, the polyurethane fiber substrate, the urethane vinyl adhesive PSA-A layer and the urethane vinyl adhesive PSA-B layer are all in the shape of a circle, and the polyurethane The radius of the substrate is smaller than the radius of the polyurethane fiber substrate, and the central portion thereof forms a groove-free region having a circular shape and having the same center as the polyurethane fiber substrate.
The polishing pad according to claim 2, wherein the polyurethane fiber substrate has a diameter of from 350 mm to 1100 mm.
The polishing pad according to claim 3, wherein the groove-free area is provided with a coded mark area, the groove-free area has a diameter of 10 mm to 60 mm, and the coded mark area and the grooveless area. The groove regions have the same center and have a diameter of 2 mm to 20 mm.
The polishing pad according to any one of claims 1 to 4, wherein the groove has a depth of 0.5 mm to 1.5 mm and a width of 0.2 mm to 1.0 mm.
The polishing pad according to any one of claims 1 to 4, wherein the polyurethane substrate has a thickness of 1.1 mm to 3.0 mm; and the polyurethane fiber substrate has a thickness of 0.8 mm to 2.2 mm; The thickness of the polyurethane vinyl Glue PSA-A layer is 0.8 mm to 2.0 mm; the thickness of the polyurethane vinyl Glue PSA-B layer is 0.8 mm~ 2.0mm.
A method for preparing a polishing pad, comprising the steps of:

1) heating the prepolymer reactant to 75 ° C, heating the MOCA to 115 ° C, and then performing the gel at a temperature of 75 ° C to 115 ° C for a gel time of about 5 to 15 minutes, wherein the prepolymerization The weight ratio of the bulk reactant to the MOCA is 3.58:1;

2) adding 1% to 8% by weight of ultra-short polyester fiber or ultra-short aramid fiber to the prepolymer reactant, and pre-polymerizing the reactant with a stirring tank at a rotation speed of 1500 rpm to 3500 rpm MOCA is thoroughly stirred and mixed to obtain a mixture A;

3) The mixture A is placed in a centrifuge at 92 ° C to 110 ° C for high temperature gelation, gel for 30 minutes to 90 minutes to obtain a polyurethane sheet after gelation;

4) transferring the gelled polyurethane sheet obtained in the step 3) to a vulcanization oven, and vulcanizing at a temperature of 100 ° C to 120 ° C for 10 to 17 hours to obtain a vulcanized polyurethane sheet;

5) The vulcanized polyurethane sheet obtained in the step 4) is used as a polyurethane substrate, the polyurethane fiber is made into a polyurethane fiber substrate, and the polyurethane rubber PSA-A is bonded as a backing phase, and then the polyurethane fiber lining is used. The other surface of the bottom is further coated with a layer of polyurethane vinyl PSA-B, which is then stamped and formed. After molding, more than two grooves are dug on the surface of the polyurethane substrate to obtain the polishing pad.
The method for preparing a polishing pad according to claim 7, wherein the preparation steps of the ultra-short polyester fiber or the ultra-short aramid fiber are as follows: terephthalic acid or dimethyl terephthalate and ethylene The alcohol is used as a raw material through esterification or transesterification reaction and polycondensation reaction to obtain polyethylene terephthalate, which is then spun and post-treated to form the ultra-short polyester fiber or ultra-short aramid fiber;

The ultra-short polyester fiber or ultra-short aramid fiber has a diameter of 0.1 μm to 15 μm. A uniform, non-polymeric, powdered fiber.
The method of preparing a polishing pad according to claim 7 or 8, wherein the prepolymer reactant is an isocyanate-terminated reaction product formed by reacting a prepolymer polyol and a polyfunctional aromatic isocyanate, the isocyanate terminated The reaction product contains unreacted NCO in a weight percentage of 7.5% to 9.9.
The method of preparing a polishing pad according to claim 9, wherein the prepolymer polyol comprises polytetramethylene ether glycol, polypropylene ether glycol, ethylene glycol diacid or adipic acid Any one of butanediols; the polyfunctional aromatic isocyanate comprises 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4'4-diphenylmethane diisocyanate, benzene-1,5- Any of diisocyanate, dimethylamine diisocyanate, p-phenylene diisocyanate or xylene diisocyanate.