A method for improving the performance of a cmp polishing pad

Abstract

The application discloses a method for improving polishing performance of a CMP polishing pad and relates to the technical field of the CMP polishing pad. The method comprises the following steps: immersing non-woven polishing leather in a solvent containing dimethylformamide or dimethylacetamide for 10-30 min, cleaning the non-woven polishing leather, and obtaining microporous non-woven fabric; under a printing pressure of 1.2-1.8 MPa, printing filling slurry on the surface of the microporous non-woven fabric, and the filling slurry completely covers the surface of the microporous non-woven fabric; and after drying, a CMP polishing pad is obtained. The CMP polishing pad prepared by the method has a more compact surface, and the softness is reduced, which helps to reduce scratches on the surface of a polished part, improves the smoothness and flatness of the surface of the polished part, and thus improves the polishing effect and polishing efficiency of the CMP polishing pad.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of CMP polishing pads, and particularly to a method for improving polishing performance of a CMP polishing pad. BACKGROUND

[0002] Chemical mechanical polishing (CMP) is a micro-nano processing technology that combines mechanical grinding and chemical oxidation to remove the material on the surface of a workpiece being processed, so as to obtain a smooth surface to achieve super-precision non-damage surface processing and meet the flatness requirements of circuits at 0.35 μm, and is mainly used for processing of super-precision surfaces such as silicon wafers, micro integrated circuits, and memories.

[0003] The polishing step is a process combining chemical corrosion and mechanical friction. The workpiece being processed is fixed on a downward-facing polishing head and on a rotating machine table. The surface of the rotating machine table is covered with a polishing pad, and abrasive slurry with small abrasive particles flows onto the table. The material on the surface of the workpiece being processed is attacked by the abrasive particles and is ground away little by little and then washed away by the abrasive slurry. The polishing pad plays a very important role in the CMP process, and therefore, a large amount of research has been carried out on the characteristics of the polishing pad and the law of its effect on the CMP process.

[0004] Polyurethane polishing pads are widely used in the field of chemical mechanical polishing due to their excellent performance. The main factors affecting mechanical polishing include the surface roughness of the polishing pad, the composition of the polishing liquid, the concentration and flow rate of the polishing liquid, and the rotation speed of the machine table. During the polishing process, in addition to contacting the wafer surface, the polishing pad also needs to be continuously ground by a diamond grinding disc at a certain speed to maintain a certain roughness on the surface of the polishing pad while scraping away excess abrasive liquid. Polyurethane polishing pads produced with non-woven substrates are widely used in the field of chemical mechanical polishing due to their excellent performance.

[0005] In related technologies, a non-woven polishing pad is produced using an impregnation method, which includes the following components by weight percentage: solvent 40%, polyurethane resin 50%, castor oil 1%, sodium carboxymethyl cellulose 3%, silane coupling agent 2%, and talc powder 4%. After high-speed stirring of the above components, a liquid is formed, and various different non-woven polishing pads are produced by impregnating non-woven fabrics of different specifications.

[0006] However, since the non-woven fabric has pores, when the abrasive and polishing debris block the pores, scratches are easily produced on the polished surface. In addition, when the abrasive and polishing debris enter the deep pores of the non-woven fabric, they are not easy to remove. Therefore, the above non-woven polishing pad has the negative abnormalities of scratches and a rough polished surface during polishing. SUMMARY

[0007] In order to improve the polishing effect of the polishing pad, the application provides a method for improving the polishing performance of CMP polishing pad.

[0008] The application provides a method for improving the polishing performance of CMP polishing pad, which adopts the following technical scheme:

[0009] The method for improving the polishing performance of CMP polishing pad comprises the following steps:

[0010] Surface treatment: after the non-woven polishing leather is immersed in the solvent containing dimethylformamide or dimethylacetamide for 10-30 min, the non-woven polishing leather is cleaned to obtain the microporous non-woven fabric;

[0011] Printing treatment: the surface of the microporous non-woven fabric is printed with the filling slurry under the printing pressure of 1.2-1.8 MPa, the filling slurry completely covers the surface of the microporous non-woven fabric, and after drying, the CMP polishing pad is obtained.

[0012] By adopting the above technical scheme, the solvent containing dimethylformamide or dimethylacetamide can erode the surface of the non-woven polishing leather, so as to form a plurality of micropores on the surface of the non-woven polishing leather. The application controls the immersion time in the above range, which helps to control the erosion degree of the surface of the non-woven polishing leather in a suitable range, so that the microporous non-woven fabric not only has uniformly distributed micropores, but also retains good mechanical properties and softness. Cleaning can remove the residual solvent containing dimethylformamide or dimethylacetamide on the non-woven polishing leather, which is convenient for subsequent printing treatment. The filling slurry can penetrate into the micropores and pores on the surface of the microporous non-woven fabric, so as to fill the micropores on the surface and the internal pores of the microporous non-woven fabric. The existence of micropores and the above printing pressure both help the filling slurry to better penetrate into the internal pores of the microporous non-woven fabric. Moreover, since the filling slurry penetrates into the micropores and pores, it helps the filling slurry to better combine with the microporous non-woven fabric. After drying, the filling slurry is reduced to fall off, at the same time, the CMP polishing pad not only obtains a more dense surface, but also reduces the softness, which helps to reduce the surface scratching of the polished part, improves the surface smoothness and flatness of the polished part, and thus improves the polishing effect and efficiency of the CMP polishing pad.

[0013] In a specific embodiment, the printing slurry comprises the following components by weight percentage: alcohol solvent 45-55%, polyurethane resin 40-50%, castor oil 0.1-0.3%, polishing powder 0.1-0.3%, and white carbon black 0.1-0.3%.

[0014] By adopting the technical scheme, the castor oil can reduce the surface tension of the printing paste, improve the emulsification of the printing paste, and facilitate the printing paste to enter the micropores and pores of the microporous non-woven fabric. The polishing powder and the white carbon black can enter the micropores and pores of the microporous non-woven fabric and fill the micropores and pores, and the polyurethane resin can block the micropores and pores and be bonded with the non-woven fabric, which helps to prevent the printing paste from falling off after the printing paste is dried.

[0015] In one specific implementation, the alcohol solvent is an ethanol aqueous solution with a mass concentration of 50-55%.

[0016] By adopting the technical scheme, the ethanol aqueous solution with the above mass concentration can not only sufficiently dissolve the polyurethane resin, but also form a filling paste with high flowability and good permeability, which facilitates the filling paste to penetrate into the micropores and pores of the microporous non-woven fabric, and the peeling strength is higher after drying, and the filling paste is not easy to fall off.

[0017] In one specific implementation, the polishing powder includes at least one of cerium oxide, zirconium oxide, and aluminum oxide.

[0018] By adopting the technical scheme, the polishing powder can not only fill the micropores and pores of the microporous non-woven fabric, but also has the advantages of small amount, fast polishing speed, and high polishing efficiency, which helps to further improve the polishing efficiency and polishing effect of the CMP polishing pad. Moreover, the polishing powder has little pollution to the environment, which helps to improve the environmental protection of the method.

[0019] In one specific implementation, the polishing powder is a mixture of cerium oxide and zirconium oxide with a weight ratio of 1:(0.8-1.2).

[0020] By adopting the technical scheme, the zirconium oxide has high hardness and good wear resistance, the cerium oxide has lower hardness than the zirconium oxide, but the cerium oxide has certain toughness. The present application finds through experiments that the cerium oxide and the zirconium oxide with the above ratio not only help to improve the compactness of the surface of the CMP polishing pad and reduce the scratches on the surface of the polished part, but also help the CMP polishing pad to obtain excellent mechanical properties and improve the flatness and polishing effect of the CMP polishing pad.

[0021] In one specific implementation, the particle size of the polishing powder and the white carbon black is 0.5-1 μm.

[0022] By adopting the technical scheme, the polishing powder and the white carbon black with the above particle size range can better penetrate into the micropores and pores of the microporous non-woven fabric, and further improve the compactness of the surface of the CMP polishing pad, thereby further improving the polishing effect of the CMP polishing pad.

[0023] In one specific implementation, the printing paste includes the following components in the following weight percentages: alcohol solvent 45-55%, polyurethane resin 40-50%, castor oil 0.1-0.3%, polishing powder 0.1-0.3%, white carbon black 0.1-0.3%, and colorant 0.1-0.3%.

[0024] By using the above technical solution, the colorant is added, the color of the printing paste can be changed as needed, and thus a CMP polishing pad with a desired color can be obtained.

[0025] In one specific implementation, the dimethylformamide or dimethylacetamide-containing solvent further includes at least one of tetrahydrofuran or acetone.

[0026] By using the above technical solution, the tetrahydrofuran or acetone can form a solution with the dimethylformamide or dimethylacetamide, and using the above solvent not only facilitates adjustment of the etching speed, but also improves the etching effect, so that the surface of the non-woven polishing leather can form uniform micropores, the micropores are connected to the pores of the non-woven polishing leather, and the slurry can penetrate into the pores.

[0027] In one specific implementation, the dimethylformamide or dimethylacetamide-containing solvent includes dimethylformamide and acetone in a weight ratio of 1:(1-3).

[0028] By using the above technical solution, it is found through experiments that using the above proportion of dimethylformamide and acetone helps to further improve the polishing effect of the CMP polishing pad, and the solvent has low toxicity, which helps to improve the safety of the method.

[0029] In one specific implementation, in the surface treatment step, the non-woven polishing leather is immersed in the dimethylformamide or dimethylacetamide-containing solvent for 15-30 min, and then the non-woven polishing leather is cleaned with an aqueous ammonium chloride solution and deionized water alternately for 1-3 times.

[0030] By using the above technical solution, using the aqueous ammonium chloride solution and deionized water alternately for cleaning facilitates improvement of the cleaning effect and reduction of the residual dimethylformamide or dimethylacetamide-containing solvent, thereby improving the printing effect of the subsequent printing treatment step.

[0031] In summary, the present application has at least one of the following beneficial technical effects:

[0032] 1. The CMP polishing pad prepared by the method of the present application not only has a more compact surface, but also has reduced softness, which helps to reduce scratches on the surface of the polished part and improve the smoothness and flatness of the polished part, thereby improving the polishing effect and efficiency of the CMP polishing pad.

[0033] 2. The method of this application, by optimizing the composition ratio of the printing paste, helps to prevent the printing paste from falling off, improves the safety of the method, and further improves the polishing effect of the CMP polishing pad;

[0034] 3. The method of this application can reduce the residual solvent containing dimethylformamide or dimethylacetamide by improving the cleaning method in the surface treatment step, thereby improving the printing effect of subsequent printing processing steps. Detailed Implementation

[0035] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0036] Example

[0037] Example 1

[0038] This embodiment provides a method for improving the polishing performance of CMP polishing pads, comprising the following steps:

[0039] The nonwoven polished leather was moved at a linear speed of 7 m / min and entered the A immersion tank containing pure dimethylformamide. The pure dimethylformamide completely immersed the nonwoven polished leather in the A immersion tank. After moving in the A immersion tank for 20 minutes, the nonwoven polished leather was removed from the A immersion tank. Then, the nonwoven polished leather was washed three times alternately with an ammonium chloride aqueous solution with a mass concentration of 3.82 g / L and deionized water to obtain microporous nonwoven fabric.

[0040] 50 kg of 50% ethanol aqueous solution, 49.4 kg of polyurethane resin, 0.2 kg of castor oil, 0.2 kg of zirconium oxide with a particle size of 0.5-1 μm and 0.2 kg of silica with a particle size of 0.5-1 μm were mixed evenly to obtain a filler slurry.

[0041] Under a printing pressure of 1.5 MPa, a filling paste is printed onto the surface of the microporous nonwoven fabric. The filling paste completely covers the surface of the microporous nonwoven fabric. Then, after vacuum drying at 100°C, a CMP polishing pad is obtained.

[0042] Example 2

[0043] This embodiment provides a method for improving the polishing performance of CMP polishing pads. The only difference between this embodiment and Embodiment 1 is that the non-woven polishing leather is moved in the A immersion tank for 10 minutes and then removed from the A immersion tank.

[0044] Example 3

[0045] This embodiment provides a method for improving the polishing performance of CMP polishing pads. The only difference between this embodiment and Embodiment 1 is that the non-woven polishing leather is moved in the A immersion tank for 30 minutes and then removed from the A immersion tank.

[0046] Example 4

[0047] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the difference between the embodiment and the embodiment 1 is that the filling slurry is printed on the surface of the microporous non-woven fabric under a printing pressure of 1.8 MPa.

[0048] Embodiment 5

[0049] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the difference between the embodiment and the embodiment 1 is that the filling slurry is printed on the surface of the microporous non-woven fabric under a printing pressure of 1.8 MPa.

[0050] Embodiment 6

[0051] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the difference between the embodiment and the embodiment 1 is that the non-woven fabric polishing leather is moved out of the A tank after being moved in the A tank for 20 min, and then the non-woven fabric polishing leather is cleaned with the ammonium chloride aqueous solution with a mass concentration of 3.82 g / L and deionized water alternately once to obtain the microporous non-woven fabric.

[0052] Embodiment 7

[0053] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the difference between the embodiment and the embodiment 1 is that the non-woven fabric polishing leather is moved out of the A tank after being moved in the A tank for 20 min, and then the non-woven fabric polishing leather is cleaned with the ammonium chloride aqueous solution with a mass concentration of 3.82 g / L and deionized water alternately four times to obtain the microporous non-woven fabric.

[0054] Embodiment 8

[0055] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the difference between the embodiment and the embodiment 1 is that the non-woven fabric polishing leather is moved out of the A tank after being moved in the A tank for 20 min, and then the non-woven fabric polishing leather is cleaned with the ammonium chloride aqueous solution with a mass concentration of 3.82 g / L and deionized water alternately four times to obtain the microporous non-woven fabric.

[0056] Embodiment 9

[0057] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the difference between the embodiment and the embodiment 1 is that the non-woven fabric polishing leather is moved out of the A tank after being moved in the A tank for 20 min, and then the non-woven fabric polishing leather is cleaned with the ammonium chloride aqueous solution with a mass concentration of 3.82 g / L and deionized water alternately four times to obtain the microporous non-woven fabric.

[0058] Embodiment 10

[0059] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the only difference between the embodiment and the embodiment 1 is that 55 kg of an ethanol aqueous solution with a mass concentration of 50%, 44.1 kg of a polyurethane resin, 0.3 kg of castor oil, 0.3 kg of zirconium oxide with a particle size of 0.5-1 μm and 0.3 kg of white carbon black with a particle size of 0.5-1 μm are uniformly mixed to obtain a filling slurry.

[0060] Embodiment 11

[0061] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the only difference between the embodiment and the embodiment 1 is that 45 kg of an ethanol aqueous solution with a mass concentration of 50%, 44.1 kg of a polyurethane resin, 0.1 kg of castor oil, 0.1 kg of zirconium oxide with a particle size of 0.5-1 μm and 0.1 kg of white carbon black with a particle size of 0.5-1 μm are uniformly mixed to obtain a filling slurry.

[0062] Embodiment 12

[0063] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the only difference between the embodiment and the embodiment 1 is that 56 kg of an ethanol aqueous solution with a mass concentration of 50%, 42.8 kg of a polyurethane resin, 0.4 kg of castor oil, 0.4 kg of zirconium oxide with a particle size of 0.5-1 μm and 0.4 kg of white carbon black with a particle size of 0.5-1 μm are uniformly mixed to obtain a filling slurry.

[0064] Embodiment 13

[0065] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the only difference between the embodiment and the embodiment 1 is that 44 kg of an ethanol aqueous solution with a mass concentration of 50%, 55.85 kg of a polyurethane resin, 0.05 kg of castor oil, 0.05 kg of zirconium oxide with a particle size of 0.5-1 μm and 0.05 kg of white carbon black with a particle size of 0.5-1 μm are uniformly mixed to obtain a filling slurry.

[0066] Embodiment 14

[0067] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the only difference between the embodiment and the embodiment 1 is that the ethanol aqueous solution with a mass concentration of 50% is replaced by an equal amount of an ethanol aqueous solution with a mass concentration of 55%.

[0068] Embodiment 15

[0069] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the only difference between the embodiment and the embodiment 1 is that the ethanol aqueous solution with a mass concentration of 50% is replaced by an equal amount of an ethanol aqueous solution with a mass concentration of 56%.

[0070] Example 16

[0071] This example provides a method for improving the polishing performance of a CMP polishing pad, which differs from Example 1 only in that an equal amount of a 49% mass concentration aqueous ethanol solution is used instead of a 50% mass concentration aqueous ethanol solution.

[0072] Example 17

[0073] This example provides a method for improving the polishing performance of a CMP polishing pad, which differs from Example 1 only in that an equal amount of a 1:1 weight ratio mixed solvent of dimethylformamide and acetone is used instead of pure dimethylformamide.

[0074] Example 18

[0075] This example provides a method for improving the polishing performance of a CMP polishing pad, which differs from Example 1 only in that an equal amount of a 1:3 weight ratio mixed solvent of dimethylformamide and acetone is used instead of pure dimethylformamide.

[0076] Example 19

[0077] This example provides a method for improving the polishing performance of a CMP polishing pad, which differs from Example 1 only in that an equal amount of a 1:4 weight ratio mixed solvent of dimethylformamide and acetone is used instead of pure dimethylformamide.

[0078] Example 20

[0079] This example provides a method for improving the polishing performance of a CMP polishing pad, which differs from Example 1 only in that an equal amount of a 1:0.8 weight ratio mixed solvent of dimethylformamide and acetone is used instead of pure dimethylformamide.

[0080] Example 21

[0081] This example provides a method for improving the polishing performance of a CMP polishing pad, which differs from Example 1 only in that an equal amount of a 1:1 weight ratio mixed solvent of dimethylformamide and tetrahydrofuran is used instead of pure dimethylformamide.

[0082] Example 22

[0083] This example provides a method for improving the polishing performance of a CMP polishing pad, which differs from Example 1 only in that an equal amount of cerium oxide with a particle size of 0.5-1 μm is used instead of zirconium oxide with a particle size of 0.5-1 μm.

[0084] Example 23

[0085] The present embodiment provides a method for improving the polishing performance of a CMP polishing pad. The only difference between the present embodiment and embodiment 1 is that the 0.5-1 μm zirconium oxide is replaced with an equal amount of 0.5-1 μm aluminum oxide.

[0086] Embodiment 24

[0087] The present embodiment provides a method for improving the polishing performance of a CMP polishing pad. The only difference between the present embodiment and embodiment 1 is that the 0.5-1 μm zirconium oxide is replaced with an equal amount of a mixture of 0.5-1 μm cerium oxide and 0.5-1 μm zirconium oxide in a weight ratio of 1:1.

[0088] Embodiment 25

[0089] The present embodiment provides a method for improving the polishing performance of a CMP polishing pad. The only difference between the present embodiment and embodiment 1 is that the 0.5-1 μm zirconium oxide is replaced with an equal amount of a mixture of 0.5-1 μm cerium oxide and 0.5-1 μm zirconium oxide in a weight ratio of 1:0.8.

[0090] Embodiment 26

[0091] The present embodiment provides a method for improving the polishing performance of a CMP polishing pad. The only difference between the present embodiment and embodiment 1 is that the 0.5-1 μm zirconium oxide is replaced with an equal amount of a mixture of 0.5-1 μm cerium oxide and 0.5-1 μm zirconium oxide in a weight ratio of 1:1.2.

[0092] Embodiment 27

[0093] The present embodiment provides a method for improving the polishing performance of a CMP polishing pad. The only difference between the present embodiment and embodiment 1 is that the 0.5-1 μm zirconium oxide is replaced with an equal amount of a mixture of 0.5-1 μm cerium oxide and 0.5-1 μm zirconium oxide in a weight ratio of 1:0.7.

[0094] Embodiment 28

[0095] The present embodiment provides a method for improving the polishing performance of a CMP polishing pad. The only difference between the present embodiment and embodiment 1 is that the 0.5-1 μm zirconium oxide is replaced with an equal amount of a mixture of 0.5-1 μm cerium oxide and 0.5-1 μm zirconium oxide in a weight ratio of 1:1.3.

[0096] Embodiment 29

[0097] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the only difference between the embodiment and the embodiment 1 is that the zirconium oxide with a particle size of 0.5-1 micron is replaced by an equal amount of zirconium oxide with a particle size of 0.1-0.5 micron, and the white carbon black with a particle size of 0.5-1 micron is replaced by an equal amount of white carbon black with a particle size of 0.1-0.5 micron.

[0098] Embodiment 30

[0099] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the only difference between the embodiment and the embodiment 1 is that the zirconium oxide with a particle size of 0.5-1 micron is replaced by an equal amount of zirconium oxide with a particle size of 1-1.5 micron, and the white carbon black with a particle size of 0.5-1 micron is replaced by an equal amount of white carbon black with a particle size of 1-1.5 micron.

[0100] Embodiment 31

[0101] The embodiment provides a method for improving polishing performance of a CMP polishing pad, and the only difference between the embodiment and the embodiment 1 is that 50 kg of an ethanol aqueous solution with a mass concentration of 50%, 49.2 kg of a polyurethane resin, 0.2 kg of castor oil, 0.2 kg of zirconium oxide with a particle size of 0.5-1 micron, 0.2 kg of white carbon black with a particle size of 0.5-1 micron and 0.2 kg of titanium white with a particle size of 0.5-1 micron are uniformly mixed to obtain a filling slurry.

[0102] Comparative Example

[0103] Comparative Example 1

[0104] The comparative example provides a method for improving polishing performance of a CMP polishing pad, and the only difference between the comparative example and the embodiment 1 is that 50 kg of an ethanol aqueous solution with a mass concentration of 50%, 49.4 kg of a polyurethane resin, 0.2 kg of castor oil, 0.2 kg of zirconium oxide with a particle size of 0.5-1 micron and 0.2 kg of white carbon black with a particle size of 0.5-1 micron are uniformly mixed to obtain a filling slurry.

[0105] Under a printing pressure of 1.5 MPa, the filling slurry is printed on the surface of the non-woven polishing leather, the filling slurry completely covers the surface of the non-woven polishing leather, and then, after vacuum drying at 100 DEG C, a CMP polishing pad is obtained.

[0106] Comparative Example 2

[0107] The comparative example provides a method for improving the polishing performance of a CMP polishing pad. The only difference between the comparative example and Example 1 is that the non-woven polishing leather is moved at a linear speed of 7 m / min. After the non-woven polishing leather enters the A immersion tank containing pure dimethylformamide, the pure dimethylformamide completely immerses the non-woven polishing leather. The non-woven polishing leather is moved out of the A immersion tank after being moved in the A immersion tank for 20 min. Then, the non-woven polishing leather is cleaned with an aqueous solution of ammonium chloride having a mass concentration of 3.82 g / L and deionized water alternately for 3 times to obtain a CMP polishing pad.

[0108] Comparative Example 3

[0109] The comparative example provides a method for improving the polishing performance of a CMP polishing pad. The only difference between the comparative example and Example 1 is that the non-woven polishing leather is moved out of the A immersion tank after being moved in the A immersion tank for 9 min. The surface of the non-woven polishing leather is printed with the filling slurry under a printing pressure of 1.1 MPa.

[0110] Comparative Example 4

[0111] The comparative example provides a method for improving the polishing performance of a CMP polishing pad. The only difference between the comparative example and Example 1 is that the non-woven polishing leather is moved out of the A immersion tank after being moved in the A immersion tank for 31 min. The surface of the non-woven polishing leather is printed with the filling slurry under a printing pressure of 1.9 MPa.

[0112] Performance detection test

[0113] The CMP polishing pads prepared according to Examples 1-31 and Comparative Examples 1-4 are subjected to performance detection.

[0114] Defect rate: The Surfscan™ SP2 unpatterned wafer surface inspection tool (KLA-Tencor Corporation, Milpitas, CA) is used to determine the defect rate with a threshold of 0.049 um. The average scratch / wobble scratch defect count in the polished copper wafer under a polishing downward force of 1.135 kg (2.5 psi) is shown in Table 1.

[0115] Table 1

[0116]

[0117] It can be seen from Examples 1 and Comparative Examples 1-4 in combination with Table 1 that, compared with Example 1, the average scratch / wobble scratch defect count of Comparative Example 1 and Comparative Example 2 is significantly increased, and the average scratch / wobble scratch defect count of Comparative Example 3 and Comparative Example 4 is also increased, which indicates that the synergistic effect under the method steps and process conditions of Example 1 helps to improve the polishing effect of the polishing pad.

[0118] As can be seen from Examples 1-31 and Comparative Example 1 in combination with Table 1, the average scratch / dimpling scratch defect counts of Examples 1-31 are all less than that of Comparative Example 1, which indicates that the method steps and process conditions of Examples 1-31 are all helpful to improve the polishing effect of the polishing pad.

[0119] The specific embodiments described herein merely illustrate the application and should not be construed to limit the scope of the application. Persons skilled in the art will be able to modify the embodiments described herein without creative effort and the modifications are intended to fall within the scope of the application.

Claims

1. A method for improving the polishing performance of CMP polishing pads, characterized in that, Includes the following steps: Surface treatment: Immerse the non-woven polished leather in a solvent containing dimethylformamide or dimethylacetamide for 10-30 minutes, then clean the non-woven polished leather to obtain microporous non-woven fabric; Printing process: Under a printing pressure of 1.2-1.8 MPa, a filling paste is printed onto the surface of the microporous nonwoven fabric. The filling paste completely covers the surface of the microporous nonwoven fabric. After drying, a CMP polishing pad is obtained. The filling paste includes the following components by weight percentage: 45-55% alcohol solvent, 40-50% polyurethane resin, 0.1-0.3% castor oil, 0.1-0.3% polishing powder, and 0.1-0.3% silica.

2. The method for improving the polishing performance of a CMP polishing pad according to claim 1, characterized in that, The alcohol solvent is an aqueous solution of ethanol with a mass concentration of 50-55%.

3. The method for improving the polishing performance of a CMP polishing pad according to claim 1, characterized in that, The polishing powder includes at least one of cerium oxide, zirconium oxide, and aluminum oxide.

4. The method for improving the polishing performance of a CMP polishing pad according to claim 3, characterized in that, The polishing powder is a mixture of cerium oxide and zirconium oxide in a weight ratio of 1:(0.8-1.2).

5. The method for improving the polishing performance of a CMP polishing pad according to claim 1, characterized in that, The particle size of both the polishing powder and the silica is 0.5-1 μm.

6. The method for improving the polishing performance of a CMP polishing pad according to claim 1, characterized in that, The filler slurry comprises the following components by weight percentage: 45-55% alcohol solvent, 40-50% polyurethane resin, 0.1-0.3% castor oil, 0.1-0.3% polishing powder, 0.1-0.3% silica, and 0.1-0.3% colorant.

7. The method for improving the polishing performance of a CMP polishing pad according to claim 1, characterized in that, The solvent containing dimethylformamide or dimethylacetamide also includes at least one of tetrahydrofuran or acetone.

8. The method for improving the polishing performance of a CMP polishing pad according to claim 7, characterized in that, The solvent containing dimethylformamide or dimethylacetamide includes dimethylformamide and acetone in a weight ratio of 1:(1-3).

9. The method for improving the polishing performance of a CMP polishing pad according to claim 1, characterized in that, In the surface treatment step, the non-woven polished leather is immersed in a solvent containing dimethylformamide or dimethylacetamide for 15-30 minutes, and then cleaned with ammonium chloride aqueous solution and deionized water alternately 1-3 times.

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