A soft, porous, foamed polishing layer and polishing pads and applications containing same
By controlling the density and recovery rate of the polishing layer and using specific materials and processes to prepare a porous foam polishing layer, the performance degradation problem of soft polishing pads under high temperature and long-term stress was solved, achieving stability of polishing performance and extension of service life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WANHUA CHEM GRP ELECTRONIC MATERIALS CO LTD
- Filing Date
- 2024-11-26
- Publication Date
- 2026-05-19
AI Technical Summary
Existing soft polishing pads experience a decline in polishing performance and reduced slurry storage and pumping efficiency during use due to increased temperature and prolonged stress, resulting in a shortened lifespan and increased costs.
By controlling the density of the polishing layer and the porous foam polishing layer with a recovery rate of >90% after 40 hours under 50℃ and 18Kpa force, the polishing layer is prepared using materials such as polyurethane resin and combined with a non-solvent phase inversion method. The adhesive layer is then connected to the intermediate support layer and the backing release layer through surface sanding and pressing groove treatment.
It ensures sufficient slurry storage and stability of the polishing layer substrate structure during the polishing process, extends the service life of the polishing pad, and reduces the cost of use.
Smart Images
Figure CN119369313B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical mechanical polishing technology, specifically to a soft porous foam polishing layer, a polishing pad containing the same, and its applications. Background Technology
[0002] Chemical mechanical polishing (CMP) combines the abrasive action of nanoscale particles with the chemical etching effect of a polishing slurry to planarize the surface of a workpiece on a polishing pad. CMP is widely used in the planarization process of semiconductor wafers and is an indispensable processing step in the production of wafers used to manufacture electronic components.
[0003] As a key consumable in the chemical mechanical polishing process, soft polishing pads are often used as finishing or final polishing to achieve a low defect rate for polishing materials.
[0004] Current adjustments to soft polishing pads mostly focus on modifying the pore shape to improve polishing speed. For example, patent CN102029577A provides a polishing pad with a dual-pore structure, and patent CN113524026A provides an offset multi-pore polishing pad. However, for soft polishing pads, during use, the surface temperature increases as the polishing process progresses, and prolonged pressure causes deformation of the pad matrix, compression of the pore structure, and a decrease in slurry storage and pumping efficiency, leading to a decline in polishing performance and a reduced lifespan. Frequent pad replacements increase operating costs. Summary of the Invention
[0005] The inventors of this invention unexpectedly discovered that by controlling the density of the polishing layer and the recovery rate after 40 hours under a force of 18 kPa within a specific range, sufficient slurry storage can be guaranteed during the polishing process, while ensuring the stability of the polishing layer substrate structure. This allows the substrate to have better elastic recovery under high temperature and long-term stress, ensuring the pumping efficiency of slurry, effectively extending the service life of the polishing pad, and reducing the cost of use, thus completing this invention.
[0006] One object of the present invention is to provide a soft porous foam polishing layer having a specific polishing layer density and a recovery rate of 40 hours under a force of 18 kPa at 50°C.
[0007] Another object of the present invention is to provide a polishing pad containing such a soft, porous foam polishing layer.
[0008] Another object of the present invention is to provide the application of such polishing pads in chemical mechanical polishing.
[0009] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:
[0010] A soft, porous foam polishing layer, the density of which is greater than or equal to 0.20 g / cm³. 3 Less than or equal to 0.23 g / cm³ 3 Furthermore, the recovery rate is >90% after 40 hours at 50℃ and under a force of 18 kPa.
[0011] In one specific embodiment, the polishing layer material is one or more of polyurethane resin, polyvinyl chloride resin, and epoxy resin, preferably polyurethane resin, preferably with a 100% modulus of 4-9 MPa, more preferably 5-8 MPa, and the elongation at break of the polyurethane resin is 400-700%, more preferably 500-600%.
[0012] In a preferred embodiment, the polished layer exhibits a recovery rate of >95% after 40 hours at 50°C and under a force of 18 kPa.
[0013] In one specific implementation, the polishing layer is prepared by a solvent-free phase inversion method.
[0014] In one specific implementation, the non-solvent phase inversion method includes the following steps:
[0015] i) Formulate the resin, additives, and solvents into a uniform coating slurry;
[0016] ii) Apply the coating slurry evenly onto the support layer and cure it in the coagulation bath;
[0017] iii) Wash and dry.
[0018] On the other hand, a chemical mechanical polishing pad includes the aforementioned soft porous foam polishing layer, wherein the polishing layer is surface sanded and grooved, and is sequentially connected to an intermediate support layer and a backing release layer via an adhesive layer.
[0019] In one specific implementation, the intermediate support layer material comprises any one of textile materials, non-woven materials, and rigid film materials; the backing release layer is a double-sided adhesive material with release paper.
[0020] On the other hand, the aforementioned chemical mechanical polishing pads are used in chemical mechanical polishing.
[0021] Compared with the prior art, the polishing layer and chemical mechanical polishing pad of the present invention have the following beneficial effects:
[0022] The polishing layer prepared by the method of the present invention has a moderate density, which can ensure sufficient slurry storage during the polishing process. On the other hand, it ensures the structural stability of the polishing layer substrate, so that it has better elastic recovery under high temperature and long-term stress, effectively extending the service life of the polishing pad and reducing the cost of use. Attached Figure Description
[0023] Figure 1 This is a comparison chart of the removal rates of the polishing pads in the embodiments and comparative examples of the present invention. Detailed Implementation
[0024] To better understand the technical solution of the present invention, the following embodiments will further illustrate the method provided by the present invention. However, the present invention is not limited to the listed embodiments, but should also include any other known modifications within the scope of the claims of the present invention.
[0025] A chemical mechanical polishing pad comprising a soft, porous foam polishing layer, the surface of which is sanded and grooved, 0.20 g / cm³. 3 ≤Polished layer density≤0.23g / cm³ 3 Furthermore, the recovery rate is >90% after 40 hours under 50℃ and 18Kpa force; the polishing layer is sequentially connected to the intermediate support layer and the backing release layer through the adhesive layer to obtain the chemical mechanical polishing pad.
[0026] Specifically, the polishing layer material is one or a mixture of polyurethane resin, polyvinyl chloride resin, and epoxy resin, preferably polyurethane resin, and more preferably wet-process polyurethane resin; the solid content of the wet-process polyurethane resin is not particularly limited, for example, generally 30%. Preferably, the 100% modulus of the wet-process polyurethane resin used in this invention is 4-9 MPa, wherein 100% modulus can also be referred to as 100% mold or 100% modulus, which have the same meaning in this invention, for example including but not limited to 4 MPa, 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, preferably 5-8 MPa. The elongation at break of the polyurethane resin is 400-700%, for example including but not limited to 400%, 500%, 600%, 700%, preferably 500-600%.
[0027] Specifically, the polishing layer is prepared by a non-solvent phase inversion method. Specifically, a polyurethane resin coating slurry of a certain thickness is applied to a support layer, cured in a coagulation bath, and then washed and dried to obtain the polishing layer. The density of the polishing layer can be adjusted by regulating the formulation and process. For example, the composition of the polyurethane coating slurry can be adjusted by adding suitable surfactants, such as anionic or nonionic surfactants, but not limited to these. The concentration and temperature of the coagulation bath can also be adjusted. The coagulation bath is preferably an aqueous solution containing DMF with a mass concentration of 10-16%, including but not limited to 10%, 11%, 12%, 13%, 14%, 15%, and 16%, preferably 12-15%. The coagulation bath temperature is 20-25°C, including but not limited to 20°C, 21°C, 22°C, 23°C, 24°C, and 25°C, preferably 22-24°C, and preferably 0.20 g / cm³. 3 ≤Polished layer density≤0.23g / cm³ 3 For example, including but not limited to 0.20 g / cm³ 3 0.21 g / cm 3 0.22g / cm 3 0.23g / cm 3 etc.
[0028] Specifically, the polished layer is pressurized at 50°C with a force of 18 kPa. Every 2 hours, the pressure is removed, and the thickness recovery amount is recorded 5 seconds and 10 seconds after the pressure is removed. The ratio of the thickness recovery amount in 10 seconds to the thickness reduction due to pressure is recorded as the recovery rate. This is done for a total of 40 hours, and the average recovery rate is recorded. Preferably, the average recovery rate is >90%, such as including but not limited to 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc., and more preferably >95%.
[0029] Specifically, the surface of the polished layer is sanded, and there are no special restrictions on the sanding method. For example, a horizontal belt sander, a vertical belt sander, etc. can be used.
[0030] Specifically, the polished layer surface is pressed with grooves. There are no special restrictions on the groove forming method. For example, it can be formed by hot pressing mold, mechanical grooving, etc. There are also no special restrictions on the groove shape. For example, it can be straight, grid, spiral, etc.
[0031] Specifically, the polishing layer is sequentially connected to the intermediate support layer and the backing release layer via an adhesive layer. The intermediate support layer is made of textile materials, non-woven materials, or rigid film materials, such as polyurethane-impregnated felt, textile materials such as thick flannel, and rigid film materials such as PET film, PC film, etc. The backing release layer is preferably a double-sided adhesive material with release paper.
[0032] Specifically, polishing pads can be used in the field of chemical mechanical polishing, including but not limited to the chemical mechanical polishing of silicon wafers, SiC, sapphire, etc.
[0033] The present invention will be further explained and illustrated below through more specific embodiments, but these do not constitute any limitation.
[0034] The main sources of raw materials used in the embodiments and comparative examples of the present invention are shown below:
[0035] Table 1. Sources of main raw materials for examples and comparative examples
[0036] Raw material name factory MDI-100 Wanhua Chemical WHP-202 Wanhua Chemical WHP-204 Wanhua Chemical CMA-44 BGI Chemistry CMA-2085 BGI Chemistry ODX-218 BGI Chemistry HDW-3050T BGI Chemistry N,N-Dimethylformamide Hualu Hengsheng
[0037] Unless otherwise specified, all other raw materials or reagents are obtained through commercially available channels.
[0038] Polishing test: Using an EBARAFREX 300 polisher, CMC D3586 polishing fluid, Oxide (PETEOS), Saesol AG62 dresser, and a 775mm diameter polishing pad.
[0039] The polishing parameters are as follows: polishing pressure 1.7 psi, polishing speed TT / TR: 95 / 86 rpm, polishing fluid flow rate 300 mL / min, and polishing time 60 s.
[0040] Polishing rate RR (angstroms / minute) test: After PETEOS is chemically and mechanically polished, the thickness difference and mass difference before and after polishing are measured using a thickness gauge and a balance to evaluate the polishing rate;
[0041] 100% Modulus Test of Polyurethane Resin: Prepare a tensile specimen with a length of 75 mm and a width of 25 mm according to the method in QB / T 4197-2011. Perform a tensile test using a tensile testing machine at a speed of 100 ± 5 mm / min. Calculate the 100% modulus value of the resin using the tensile force value when the elongation is 100%.
[0042] Polyurethane resin elongation at break test: Prepare a tensile specimen with a length of 75 mm and a width of 25 mm according to the method in QB / T 4197-2011. Perform tensile test using a tensile testing machine at a speed of 100±5 mm / min. Calculate the elongation at break of the specimen according to the distance difference between the scales before and after the specimen breaks.
[0043] Polishing layer density test: Cut a 10cm×10cm sanded polishing layer, measure the thickness of the polishing layer with a micrometer, weigh the polishing layer with a balance, calculate the density, and take 3 samples for each sample and take the average density.
[0044] 40-hour average recovery rate test of polished layer: A compressibility measuring device was used in a 50℃ constant temperature and humidity oven. The pressure surface was set to 1cm, the initial load was 18g, and the thickness was measured and recorded as t after 30s of pressure application. 0， The final load was 180g, and the thickness was measured and recorded as t after 30 seconds of pressure application. 1， After applying pressure for 40 hours, the final load was removed. The thickness after 30 seconds of testing was recorded as t2. The recovery rate (%) =
[0045] 100×(t2-t1) / (t0-t1).
[0046] Example 1
[0047] Polyurethane resin preparation: 1050g DMF, 99g BDO, 1000g WHP-202, 4.2g antioxidant 1135, and 2.4g stannous octoate were added to a reactor and stirred while maintaining the temperature at 70-80℃. MDI 100 (total 401g) was added in 5 portions, and the remaining 2332g DMF was added in 6 portions. When the resin viscosity reached 80000-10000cp, 2g methanol was added at 25℃, and the mixture was stirred evenly before discharging. The 100% modulus of the resin was tested to be 4MPa, and the elongation at break was 526%.
[0048] Polishing layer preparation: 100 parts of the above polyurethane resin, 3 parts of Span-83, and 50 parts of N,N-dimethylformamide were formulated into a polyurethane slurry. The slurry was uniformly coated onto a PET film with a thickness of 1.4 mm using a coating machine. The film was then immersed in a 20°C, 10% DMF aqueous solution for curing and molding for 50 min. After washing and drying, the surface was sanded with 180-grit sandpaper using a vertical belt sander, with the removal amount controlled to be within 0.20 mm. The polishing layer was obtained by embossing a grid-type groove using a 130°C hot press mold.
[0049] The polishing layer is then combined with polyurethane-impregnated felt material, adhesive backing is applied, and a release layer is attached to obtain a chemical mechanical polishing pad.
[0050] Example 2
[0051] Polyurethane resin preparation: 1077g DMF, 82g EG, 1000g WHP-204, 11354.2g antioxidant, and 2.4g stannous octoate were added to a reactor and stirred while maintaining the temperature at 70-80℃. MDI 100 (total 456g) was added in 5 portions, and the remaining 2512g DMF was added in 6 portions. When the resin viscosity reached 80000-10000cp, 2g methanol was added at 25℃, and the mixture was stirred evenly before discharging. The 100% modulus of the resin was tested to be 5MPa, and the elongation at break was 560%.
[0052] Polishing layer preparation: 100 parts of the above polyurethane resin, 1 part of Tween 20, and 45 parts of N,N-dimethylformamide were mixed to form a polyurethane slurry. The slurry was uniformly coated onto a PET film with a thickness of 1.3 mm using a coating machine. The film was then immersed in a 23°C, 14% DMF aqueous solution for curing and shaping for 50 min. After washing and drying, the surface was sanded with 180-grit sandpaper using a vertical belt sander, with the removal amount controlled to be within 0.20 mm. The polishing layer was obtained by embossing a grid-like groove using a 130°C hot press mold.
[0053] The polishing layer is then combined with a 0.188mm thick PET film, adhesive backing is applied, and a release layer is attached to obtain a chemical mechanical polishing pad.
[0054] Example 3
[0055] Polyurethane resin preparation: 1147g DMF, 102g BDO, 1000g CMA-44, 4.2g antioxidant 1135, and 2.4g stannous octoate were added to a reactor and stirred while maintaining the temperature at 70-80℃. MDI 100 (total 537g) was added in 5 portions, and the remaining 2677g DMF was added in 6 portions. When the resin viscosity reached 80000-10000cp, 2g methanol was added at 25℃, and the mixture was stirred evenly before discharging. The 100% modulus of the resin was tested to be 8MPa, and the elongation at break was 510%.
[0056] Polishing layer preparation: 100 parts of the above polyurethane resin, 2 parts of OP-7, and 50 parts of N,N-dimethylformamide were formulated into a polyurethane slurry. The slurry was uniformly coated onto the PET film with a thickness of 1.5 mm using a coating machine. The film was then immersed in a 25°C, 15% DMF aqueous solution for curing and molding for 50 min. After washing and drying, the surface was sanded with 180-grit sandpaper using a vertical belt sander, with the removal amount controlled to be within 0.20 mm. The polishing layer was obtained by embossing a grid-type groove using a 130°C hot press mold.
[0057] The polishing layer is then combined with a 0.188mm thick PC film, and an adhesive backing is applied, followed by a release layer to obtain a chemical mechanical polishing pad.
[0058] Example 4
[0059] Polyurethane resin preparation: 1093g DMF, 102g EG, 510g WHP-202, 490g WHP-204, 4.2g antioxidant 1135, and 2.4g stannous octoate were added to a reactor and stirred while maintaining the temperature at 70-80℃. MDI 100 (total 537g) was added in 5 portions, and the remaining 2552g DMF was added in 6 portions. When the resin viscosity reached 80000-10000cp, 2g methanol was added at 25℃, and the mixture was stirred evenly before discharging. The 100% modulus of the resin was tested to be 8.5MPa, and the elongation at break was 570%.
[0060] Polishing layer preparation: 100 parts of the above polyurethane resin, 2 parts of polyethylene glycol (400) monostearate, and 65 parts of N,N-dimethylformamide were formulated into a polyurethane slurry. The slurry was uniformly coated on a PET film with a thickness of 1.3 mm, and then immersed in a 21°C, 13% DMF aqueous solution to cure for 50 min. After washing and drying, the surface was sanded with 180-grit sandpaper using a vertical belt sander, with the removal amount controlled to be within 0.20 mm. The polishing layer was obtained by embossing a grid-type groove using a 130°C hot press mold.
[0061] The polishing layer is then combined with polyurethane-impregnated felt material, adhesive backing is applied, and a release layer is attached to obtain a chemical mechanical polishing pad.
[0062] Comparative Example 1
[0063] The polyurethane resin was prepared using the same steps as in Example 1.
[0064] The polished layer was prepared using the same steps as in Example 1, except that the concentration of the coagulation bath was 6%.
[0065] The polishing layer is then combined with polyurethane-impregnated felt material, adhesive backing is applied, and a release layer is attached to obtain a chemical mechanical polishing pad.
[0066] Comparative Example 2
[0067] Polyurethane resin preparation: 1000g DMF, 60g EG, 1000g WHP-204, 11354.2g antioxidant, and 2.4g stannous octoate were added to a reactor and stirred while maintaining the temperature at 70-80℃. MDI 100 (total 368g) was added in 5 portions, and the remaining 2333g DMF was added in 6 portions. When the resin viscosity reached 80000-10000cp, 2g methanol was added at 25℃, and the mixture was stirred evenly before discharging. The 100% modulus of the resin was tested to be 3MPa, and the elongation at break was 590%.
[0068] The polishing layer was prepared using the same steps as in Example 2.
[0069] The polishing layer is then combined with a 0.188mm thick PET film, adhesive backing is applied, and a release layer is attached to obtain a chemical mechanical polishing pad.
[0070] Comparative Example 3
[0071] Polyurethane resin preparation: 1093g DMF, 115.8g BDO, 100g CMA-44, 900g CMA-2085, 4.2g antioxidant 1135, and 2.4g stannous octoate were added to a reactor and stirred while maintaining the temperature at 70-80℃. MDI 100 (total 447g) was added in 5 portions, and the remaining 2552g DMF was added in 6 portions. When the resin viscosity reached 80000-10000cp, 2g methanol was added at 25℃, and the mixture was stirred evenly before discharging. The 100% modulus of the resin was tested to be 7MPa, and the elongation at break was 380%.
[0072] The polishing layer was prepared using the same steps as in Example 2.
[0073] The polishing layer is then combined with a 0.188mm thick PET film, adhesive backing is applied, and a release layer is attached to obtain a chemical mechanical polishing pad.
[0074] Comparative Example 4
[0075] Polyurethane resin preparation: 1206g DMF, 158g BDO, 1000g ODX-218, 4.2g antioxidant 1135, and 2.4g stannous octoate were added to a reactor and stirred while maintaining the temperature at 70-80℃. MDI 100 (total 565g) was added in 5 portions, and the remaining 2814g DMF was added in 6 portions. When the resin viscosity reached 80000-10000cp, 2g methanol was added at 25℃, and the mixture was stirred evenly before discharging. The 100% modulus of the resin was tested to be 11MPa, and the elongation at break was 360%.
[0076] The polishing layer was prepared using the same steps as in Example 2.
[0077] The polishing layer is then combined with a 0.188mm thick PET film, adhesive backing is applied, and a release layer is attached to obtain a chemical mechanical polishing pad.
[0078] Comparative Example 5
[0079] The polished layer was prepared using the same steps as in Example 3, except that the resin HDW-3050T was used (the resin had a 100% modulus of 6 MPa and an elongation at break of 800%).
[0080] The polishing layer is then combined with a 0.188mm thick PC film, and an adhesive backing is applied, followed by a release layer to obtain a chemical mechanical polishing pad.
[0081] The test results of the polished layer density and average recovery rate over 40 hours obtained from the examples and comparative examples are shown in Table 2.
[0082] Table 2. Test results of polishing layer density and average recovery rate after 40 hours.
[0083]
[0084] The removal rates were obtained by polishing tests on the polishing pads prepared in the examples and comparative examples. The test results are as follows: Figure 1 As shown.
[0085] pass Figure 1 Test results show that the polishing pad prepared by this invention can maintain the stability of the polishing rate and effectively extend its service life.
[0086] Although the present invention has been described in detail through the preferred embodiments described above, it should be understood that the above description should not be considered as a limitation of the present invention. Those skilled in the art will understand that modifications or adjustments can be made to the present invention based on the teachings of this specification. These modifications or adjustments should also be within the scope defined by the claims of the present invention.
Claims
1. A soft, porous foam polishing layer, characterized in that, The density of the polished layer is greater than or equal to 0.20 g / cm3 and less than or equal to 0.23 g / cm3, and the average recovery rate is greater than 90% after 40 hours at 50°C and under a force of 18 kPa. The polished layer is prepared by a non-solvent phase inversion method, including the following steps: i) Formulate a uniform coating slurry by mixing resin, additives, and solvent; wherein the resin is a polyurethane resin, and the 100% modulus of the polyurethane resin is 4-9 MPa, and the elongation at break is 400-700%; ii) The coating slurry is evenly applied to the support layer and cured in a coagulation bath; the coagulation bath is an aqueous solution containing DMF with a mass concentration of 10-16%; iii) Wash and dry.
2. The porous foam polishing layer according to claim 1, characterized in that, The 100% modulus of the polyurethane resin is 5-8 MPa.
3. The porous foam polishing layer according to claim 1, characterized in that, The elongation at break of the polyurethane resin is 500-600%.
4. The porous foam polishing layer according to any one of claims 1 to 3, characterized in that, The polished layer has an average recovery rate of >95% after 40 hours at 50°C and under a force of 18 kPa.
5. A chemical mechanical polishing pad, characterized in that, The invention includes a soft porous foam polishing layer as described in any one of claims 1 to 4, wherein the polishing layer is surface sanded and grooved, and is sequentially connected to an intermediate support layer and a backing release layer via an adhesive layer.
6. The chemical mechanical polishing pad according to claim 5, characterized in that, The intermediate support layer material includes any one of textile materials, non-woven materials, and rigid film materials; the backing release layer is a double-sided adhesive material with release paper.
7. The application of the chemical mechanical polishing pad according to claim 5 or 6 in chemical mechanical polishing.