A cmp polishing pad and method of making the same

Abstract

The application relates to a polishing material, and particularly discloses a CMP polishing pad and a preparation method thereof. The preparation method of the CMP polishing pad comprises the following steps: firstly, stirring part of solvent, adding part of an additive, uniformly stirring, increasing the rotating speed, then adding part of the additive, uniformly stirring, and obtaining a mixture A; uniformly stirring the remaining solvent and the remaining additive, slowly adding part of polyurethane resin in the stirring process, uniformly stirring, slowly adding carbon powder again, uniformly stirring, increasing the rotating speed, continuously stirring, then adding part of the polyurethane resin again, uniformly stirring, and obtaining a mixture B; adding the mixture A into the mixture B, uniformly stirring, adding the remaining polyurethane resin, uniformly stirring and mixing, obtaining a mixture C, filtering, vacuum degassing, and obtaining a polyurethane slurry; and coating the polyurethane slurry on non-woven fabric to obtain the CMP polishing pad.

Description

TECHNICAL FIELD

[0001] The application relates to a polishing material, in particular to a CMP polishing pad and a preparation method thereof. BACKGROUND

[0002] CMP is a chemical mechanical polishing technology, which uses the mechanical grinding of abrasive particles and the chemical action of oxidizing agents to cooperate to remove the chemical reaction products on the surface of the polished part, so that a smooth surface is obtained to realize ultra-precision non-damage surface processing and meet the flatness requirements of circuits under 0.35 mu m. The polishing step is a process combining chemical corrosion and mechanical friction. The workpiece to be processed is fixed on the downward-facing grinding head and on the rotating machine table. The surface of the rotating machine table is covered with a polishing pad, and the abrasive slurry with small abrasive particles flows onto the table. The surface material of the workpiece to be processed is attacked by the abrasive particles and polished, and then washed away by the abrasive slurry. The workpiece surface is polished due to the combined action of the rotation friction of the two tracks and the abrasive slurry. The polishing pad plays a very important role in the CMP process. The polyurethane polishing pad produced by the non-woven fabric substrate is widely used in the field of chemical mechanical polishing due to its excellent performance.

[0003] The commonly used non-woven fabric polishing pad is produced by coating. Specifically, after the solvent, polyurethane resin, carbon powder and additives are fully stirred, a viscous liquid is formed, which is coated on the surface of non-woven fabric of different specifications through the production line. After immersion and solidification, various non-woven fabric polishing pads of different specifications are produced. However, although the traditional polishing pad can realize polishing and has long service life, the polishing efficiency is not high. SUMMARY

[0004] In order to improve the polishing efficiency of the prepared polishing pad, the application provides a CMP polishing pad and a preparation method thereof.

[0005] In a first aspect, the application provides a preparation method of a CMP polishing pad, which adopts the following technical scheme:

[0006] A preparation method of a CMP polishing pad comprises the following steps:

[0007] Preparation of the mixed material A: under the rotation speed of 900-1100 r / min, part of the solvent is stirred, and part of the additive is added in the stirring process. After uniform stirring, the rotation speed is increased to 1100-1300 r / min, and then part of the additive is added and stirred uniformly to obtain the mixed material A;

[0008] Mixing material B preparation: the rest of the solvent and the rest of the auxiliary are stirred uniformly at a rotating speed of 900-1100 r / min, and part of the polyurethane resin is slowly added in the stirring process, and stirred uniformly, and then the carbon powder is slowly added, and stirred uniformly, and then the rotating speed is increased to 1400-1600 r / min, and the stirring is continued, and then part of the polyurethane resin is added, and stirred uniformly, to obtain the mixing material B;

[0009] Slurry preparation: the mixing material A is added to the mixing material B at a rotating speed of 1100-1300 r / min, and stirred uniformly, and then the rest of the polyurethane resin is added, and stirred and mixed uniformly, to obtain the mixing material C, and filtered, and vacuum degassed, to obtain the polyurethane slurry; coating: the polyurethane slurry is coated on the non-woven fabric, to obtain the CMP polishing pad.

[0010] By adopting the technical scheme, the polyurethane resin and the auxiliary are added in batches when the polyurethane slurry is prepared, so that the raw materials in the polyurethane slurry are mixed uniformly, thereby improving the strength and performance of the polishing pad prepared, and thus improving the polishing efficiency of the polishing pad.

[0011] In a specific implementation, the weight ratio of the three batches of polyurethane resin is 1:(2.5-3.5):(5.5-6.5).

[0012] In a specific implementation, the weight ratio of the three batches of auxiliary is 1:(0.1-0.15):(0.2-0.3).

[0013] By adopting the technical scheme, the amount of the polyurethane resin and the auxiliary added in batches is further limited in the application, so that the raw materials in the polyurethane slurry are more uniformly mixed, and the polishing efficiency of the polishing pad prepared can be further improved.

[0014] In a specific implementation, the coating step is: the non-woven fabric is first immersed in the polyurethane slurry, taken out, then added to the N,N-dimethylformamide aqueous solution, taken out again, and finally dried at 155-165 ℃, to obtain the CMP polishing pad.

[0015] By adopting the technical scheme, the polishing pad is first added to the N,N-dimethylformamide aqueous solution for pre-coagulation, and then dried, so that the polyurethane is tightly combined with the non-woven fabric fibers, thereby improving the strength of the polishing pad prepared.

[0016] In a second aspect, the application provides a CMP polishing pad, which adopts the following technical scheme:

[0017] A CMP polishing pad is prepared by the method for preparing the CMP polishing pad.

[0018] By adopting the technical scheme, the CMP polishing pad prepared by the preparation method of the CMP polishing pad has high polishing efficiency.

[0019] In a specific embodiment, the raw material of the polishing pad comprises the following components by weight: 30-50 parts of solvent, 40-50 parts of polyurethane resin, 0.3-0.9 parts of carbon powder, and 10-20 parts of additives.

[0020] In a specific embodiment, the additives comprise surfactants, diluents, and inorganic fillers.

[0021] In a specific embodiment, the diluents comprise a mixture of formyl dimethyl amine and hexahydrobenzene.

[0022] By adopting the technical scheme, the combination of formyl dimethyl amine and hexahydrobenzene makes the pore structure of the prepared polishing pad complete and uniform, thereby further improving the polishing efficiency of the prepared polishing pad.

[0023] In a specific embodiment, the inorganic fillers comprise one or more of zirconium oxide, cerium oxide, aluminum oxide, and silicon dioxide.

[0024] In summary, the present application has at least one of the following beneficial technical effects:

[0025] 1. In the present application, the polyurethane resin and the additives are added in batches when preparing the polyurethane slurry, so that the raw materials in the polyurethane slurry are uniformly mixed, thereby improving the strength and performance of the prepared polishing pad, and thus improving the polishing efficiency of the polishing pad.

[0026] 2. In the present application, the polishing pad is first pre-coagulated in an aqueous N,N-dimethylformamide solution, and then dried, which can make the polyurethane tightly combined with the non-woven fabric fibers, thereby improving the strength of the prepared polishing pad.

[0027] 3. In the present application, the combination of formyl dimethyl amine and hexahydrobenzene makes the pore structure of the prepared polishing pad complete and uniform, thereby further improving the polishing efficiency of the prepared polishing pad. DETAILED DESCRIPTION

[0028] The present application is further described in detail below in conjunction with the examples.

[0029] All raw materials in the examples can be obtained by market purchase. The polyurethane resin has a CAS number of 9009-54-5; the particle size of the carbon powder is 7-10 microns; the particle size of the zirconium oxide is 8-10 nanometers; and the non-woven fabric is a regular mesh woven structure of non-woven polyester fabric with a void ratio of 60-80% and a fiber gap of 90-110 microns.

[0030] Example

[0031] Example 1

[0032] Example 1 provides a preparation method of CMP polishing pad, comprising the following steps:

[0033] Preparation of mixture A: under the rotation speed of 900 r / min, part of the solvent is stirred, and part of the additive is added in the stirring process. After uniform stirring, the rotation speed is increased to 1100 r / min, then part of the additive is added, and the material is uniformly stirred for 20 min to obtain mixture A;

[0034] Preparation of mixture B: under the rotation speed of 900 r / min, the remaining solvent and the remaining additive are stirred uniformly, and part of the polyurethane resin is slowly added in the stirring process. After stirring for 10 min, 0.3 kg of carbon powder is slowly added, and then stirred for 10 min until the material is uniform. The rotation speed is increased to 1400 r / min, and the stirring is continued for 20 min. Then part of the polyurethane resin is added, and the material is uniformly stirred for 20 min to obtain mixture B; wherein the solvent is N,N-dimethylformamide, the weight is 30 kg, and the weight ratio of the two batches of solvent added is 62.3:37.6; the weight of the polyurethane resin is 40 kg, and the weight ratio of the three batches of polyurethane resin added is 1:2:5; the weight of the additive is 10 kg, and the weight ratio of the three batches of additive added is 1:0.05:0.15, the additive includes surfactant, diluent, and inorganic filler, and the weight ratio of the surfactant, diluent, and inorganic filler is 1:1:8, the surfactant is polysiloxane-polyoxyalkylene ether block copolymer, the diluent is a mixture of formyldimethylamine and hexahydrobenzene, and the weight ratio of the mixture of formyldimethylamine and hexahydrobenzene is 1:1, and the inorganic filler is zirconium oxide;

[0035] Preparation of slurry: under the rotation speed of 1100 r / min, mixture A is added to mixture B, and stirred for 20 min until the material is uniform. Then the remaining polyurethane resin is added, and stirred for 20 min until the material is uniform to obtain mixture C. The mixture C is filtered with a 40 mesh filter screen, and then added into a vacuum barrel for vacuum degassing for 1.5 h to obtain a polyurethane slurry;

[0036] Coating: the non-woven fabric is first immersed in the polyurethane slurry, and then extruded by a metal roller. The excess polyurethane slurry on the surface is removed by a scraper, and then added into an N,N-dimethylformamide aqueous solution. After 35 min, the non-woven fabric is taken out and dried at 160°C to obtain a CMP polishing pad; wherein the weight fraction of N,N-dimethylformamide in the N,N-dimethylformamide aqueous solution is 20%.

[0037] Example 2

[0038] Example 2 differs from Example 1 in that the weight ratio of the polyurethane resin added in three batches is 1 : 2.5 : 5.5 in turn; the remaining steps are consistent with Example 1.

[0039] Example 3

[0040] Example 3 differs from Example 1 in that the weight ratio of the polyurethane resin added in three batches is 1 : 3 : 6 in turn; the remaining steps are consistent with Example 1.

[0041] Example 4

[0042] Example 4 differs from Example 1 in that the weight ratio of the polyurethane resin added in three batches is 1 : 3.5 : 6.5 in turn; the remaining steps are consistent with Example 1.

[0043] Example 5

[0044] Example 5 differs from Example 1 in that the weight ratio of the polyurethane resin added in three batches is 1 : 4 : 7 in turn; the remaining steps are consistent with Example 1.

[0045] Example 6

[0046] Example 6 differs from Example 3 in that the weight ratio of the auxiliary added in three batches is 1 : 0.1 : 0.2 in turn; the remaining steps are consistent with Example 3.

[0047] Example 7

[0048] Example 7 differs from Example 3 in that the weight ratio of the auxiliary added in three batches is 1 : 0.12 : 0.25 in turn; the remaining steps are consistent with Example 3.

[0049] Example 8

[0050] Example 8 differs from Example 3 in that the weight ratio of the auxiliary added in three batches is 1 : 0.15 : 0.3 in turn; the remaining steps are consistent with Example 3.

[0051] Example 9

[0052] Example 9 differs from Example 3 in that the weight ratio of the auxiliary added in three batches is 1 : 0.2 : 0.35 in turn; the remaining steps are consistent with Example 3.

[0053] Example 10

[0054] Example 10 differs from Example 7 in that the preparation of the mixed material A: part of the solvent is stirred at a speed of 1000 r / min, part of the auxiliary is added in the stirring process, the stirring speed is increased to 1200 r / min after uniform stirring, then part of the auxiliary is added, and the material is uniformly stirred for 20 min to obtain the mixed material A.

[0055] Mixing material B preparation: under the rotation speed of 1000 r / min, the rest of the solvent and the rest of the auxiliary agent are stirred uniformly, and part of the polyurethane resin is slowly added in the stirring process. After stirring for 10 min, 0.6 kg of carbon powder is slowly added, and after stirring for 10 min, the rotation speed is increased to 1500 r / min, and the stirring is continued for 20 min. Then part of the polyurethane resin is added, and the stirring is continued for 20 min until the material is uniform. Thus, mixing material B is obtained; wherein the solvent is N,N-dimethylformamide, and the weight is 40 kg; the weight of the polyurethane resin is 45 kg; and the weight of the auxiliary agent is 15 kg;

[0056] Slurry preparation: under the rotation speed of 1200 r / min, mixing material A is added to mixing material B, and stirred for 20 min until the material is uniform. Then the rest of the polyurethane resin is added, and stirred for 20 min until the material is uniform. Thus, mixing material C is obtained. Then, it is filtered with a 40-mesh filter screen, and then added to a vacuum barrel for vacuum degassing for 1.5 h to obtain a polyurethane slurry. The remaining steps are consistent with example 7.

[0057] Example 11

[0058] Example 11 is different from example 7 in that mixing material A preparation: under the rotation speed of 1100 r / min, part of the solvent is stirred, and part of the auxiliary agent is added in the stirring process. After stirring uniformly, the rotation speed is increased to 1300 r / min, and then part of the auxiliary agent is added. After stirring for 20 min, the material is uniform, and mixing material A is obtained.

[0059] Mixing material B preparation: under the rotation speed of 1100 r / min, the rest of the solvent and the rest of the auxiliary agent are stirred uniformly, and part of the polyurethane resin is slowly added in the stirring process. After stirring for 10 min, 0.6 kg of carbon powder is slowly added, and after stirring for 10 min, the rotation speed is increased to 1500 r / min, and the stirring is continued for 20 min. Then part of the polyurethane resin is added, and the stirring is continued for 20 min until the material is uniform. Thus, mixing material B is obtained; wherein the solvent is N,N-dimethylformamide, and the weight is 40 kg; the weight of the polyurethane resin is 45 kg; and the weight of the auxiliary agent is 15 kg;

[0060] Slurry preparation: under the rotation speed of 1300 r / min, mixing material A is added to mixing material B, and stirred for 20 min until the material is uniform. Then the rest of the polyurethane resin is added, and stirred for 20 min until the material is uniform. Thus, mixing material C is obtained. Then, it is filtered with a 40-mesh filter screen, and then added to a vacuum barrel for vacuum degassing for 1.5 h to obtain a polyurethane slurry. The remaining steps are consistent with example 7.

[0061] Example 12

[0062] Example 12 differs from Example 10 in that the diluent is formdimethylamine; the remaining steps are consistent with Example 10.

[0063] Example 13

[0064] Example 13 differs from Example 10 in that the diluent is hexahydrobenzene; the remaining steps are consistent with Example 10.

[0065] Comparative Example

[0066] Comparative Example 1

[0067] Comparative Example 1 differs from Example 1 in that 30 kg of solvent, 40 kg of polyurethane resin, 0.3 kg of carbon powder, and 10 kg of auxiliary agent are stirred at a speed of 1200 r / min until the materials are uniform, then filtered with a 40-mesh screen, and then added to a vacuum barrel for vacuum degassing for 1.5 h to obtain a polyurethane slurry; the remaining steps are consistent with Example 1.

[0068] Performance detection test removal rate: the polishing pad in each example is used to polish K9 optical glass, and the removal rate is calculated, removal rate = mass difference / (glass density * polishing area * time), the higher the removal rate, the higher the polishing efficiency of the polishing pad.

[0069] Table 1 Performance detection results of the polishing pad

[0070] Sample Removal rate (nm / min) Example 1 20.16 Example 2 26.78 Example 3 27.45 Example 4 27.01 Example 5 21.22 Example 6 31.56 Example 7 32.33 Example 8 31.98 Example 9 26.97 Example 10 33.12 Example 11 32.76 Example 12 28.17 Example 13 28.66 Comparative Example 1 13.95

[0071] In combination with Example 1 and Comparative Example 1, the polishing efficiency of the polishing pad in Example 1 is higher, and it can be seen that when preparing the polyurethane slurry, the polyurethane resin and the auxiliary agent are added in batches, so that the various raw materials in the polyurethane slurry are mixed more uniformly, which can improve the strength and performance of the prepared polishing pad, and thus improve the polishing efficiency of the polishing pad.

[0072] In combination with Examples 1-5, the polishing efficiency of the polishing pad in Examples 2-4 is higher, and it can be seen that when preparing the polyurethane slurry, the weight ratio of the three times of adding the polyurethane resin in batches is preferably 1: (2.5-3.5): (5.5-6.5) in turn, and the raw materials in the prepared polyurethane slurry are mixed more uniformly.

[0073] In combination with Example 3 and Examples 6-9, the polishing efficiency of the polishing pad in Examples 6-8 is higher, and it can be seen that when preparing the polyurethane slurry, the weight ratio of the three times of adding the auxiliary agent in batches is preferably 1: (0.1-0.15): (0.2-0.3) in turn, and the raw materials in the prepared polyurethane slurry are mixed more uniformly.

[0074] In combination with Embodiment 7, Embodiment 10 and Embodiment 11, the polishing efficiency of the polishing pads in Embodiment 7, Embodiment 10 and Embodiment 11 is not much different, which shows that when preparing the polyurethane slurry, increasing the usage amount of the raw materials and increasing the stirring speed at the same time has little effect on the performance of the prepared polyurethane slurry.

[0075] In combination with Embodiment 10, Embodiment 12 and Embodiment 13, the polishing efficiency of the polishing pad in Embodiment 10 is the highest, which shows that when preparing the polyurethane slurry, using the mixture composed of formamidine and hexahydrobenzene as the diluent makes the pore structure of the formed polishing pad complete and uniform, thus further improving the polishing efficiency of the prepared polishing pad.

[0076] The specific embodiments are only an explanation of the present application, which is not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method of making a CMP polishing pad, characterized by: The method comprises the following steps: Preparation of mixture A: part of the solvent is stirred at a rotation speed of 900-1100 r / min, and part of the auxiliary agent is added during the stirring process; after uniform stirring, the rotation speed is increased to 1100-1300 r / min, and then part of the auxiliary agent is added and stirred uniformly; mixture A is obtained; Preparation of mixture B: the remaining solvent and the remaining auxiliary agent are stirred uniformly at a rotation speed of 900-1100 r / min, and part of the polyurethane resin is slowly added during the stirring process; after uniform stirring, the carbon powder is slowly added, and the rotation speed is increased to 1400-1600 r / min for continuous stirring; then part of the polyurethane resin is added and stirred uniformly; mixture B is obtained; Preparation of slurry: mixture A is added to mixture B at a rotation speed of 1100-1300 r / min, and then the remaining polyurethane resin is added and stirred uniformly; mixture C is obtained, filtered, and vacuum degassed to obtain a polyurethane slurry; Coating: the non-woven fabric is first immersed in the polyurethane slurry, taken out, and then added to an aqueous N,N-dimethylformamide solution; after being taken out again, the CMP polishing pad is obtained by drying at 155-165°C; the weight ratio of the three batches of polyurethane resin added is 1:(2.5-3.5):(5.5-6.5); the weight ratio of the three batches of auxiliary agent added is 1:(0.1-0.15):(0.2-0.3).

2. A CMP polishing pad, characterized by: The CMP polishing pad is prepared by the method for preparing the CMP polishing pad according to claim 1.

3. The CMP polishing pad of claim 2, wherein: The raw material of the polishing pad comprises the following components in parts by weight: solvent 30-50 parts, polyurethane resin 40-50 parts, carbon powder 0.3-0.9 parts, and auxiliary agent 10-20 parts.

4. The CMP polishing pad of claim 3, wherein: The auxiliary agent comprises a surfactant, a diluent, and an inorganic filler.

5. The CMP polishing pad of claim 4, wherein: The diluent comprises a mixture of formyldimethylamine and hexahydrobenzene.

6. The CMP polishing pad of claim 4, wherein: The inorganic filler comprises one or more of zirconium oxide, cerium oxide, aluminum oxide, and silicon dioxide.