A long-life chemical mechanical polishing pad

Abstract

This invention provides a long-life chemical mechanical polishing (CMP) pad. The polishing pad includes at least a polishing layer comprising the following raw material components: polyurethane prepolymer, silicone modifier, expanded microspheres, and curing agent. Based on the total mass of the polyurethane prepolymer, the content of the silicone modifier is 0.05~8 wt%. The silicone modifier is selected from polydimethylsiloxane with multifunctional end groups selected from one or more of amino, hydroxyl, and isocyanate groups. When applied to the rough polishing of silicon oxide wafers, this polishing pad exhibits a high removal rate, resulting in a high-quality wafer surface with few scratches. Furthermore, the polishing pad has high hardness and good wear resistance, thus minimizing wear on the grooves during use and achieving a long service life.

Description

Technical Field

[0001] This invention relates to the field of chemical mechanical polishing technology, and in particular to a chemical mechanical polishing pad with a long service life. Background Technology

[0002] Chemical mechanical planarization (CMP) is a crucial polishing process widely used in integrated circuit manufacturing and is currently the only technology to achieve global planarization of the wafer surface. As semiconductor device feature sizes continue to shrink and integration density continues to increase, the requirements for wafer surface flatness are becoming increasingly stringent, highlighting the growing importance of CMP. The core purpose of CMP is to remove excess material from the wafer surface to achieve uniform wafer thickness control, thereby providing a flat processing interface for subsequent photolithography, deposition, and other processes. To achieve this goal, a CMP system typically consists of key components such as polishing pads, polishing slurries, polishing heads, and diamond disks working together.

[0003] The polishing pad, as an essential consumable in the CMP process, directly determines the polishing efficiency and effect based on its surface condition. During the actual polishing process, the diamond disk continuously trims the surface of the polishing pad to maintain the stability and roughness of its microstructure, thereby ensuring the uniformity and repeatability of the polishing process. The polishing pad surface is typically designed with grooves of specific shapes and arrangements to assist in the transport and distribution of the polishing slurry and enhance material removal efficiency. As the polishing process continues, the polishing pad is continuously consumed under the combined effects of mechanical wear and trimming, and the depth of the surface grooves gradually decreases. When the groove depth falls below a certain threshold, the transport efficiency of the polishing slurry decreases significantly, the pressure distribution on the wafer surface becomes uneven, and the polishing results become unstable, failing to meet process control requirements. At this point, the polishing pad is considered to have reached the end of its service life and needs to be replaced.

[0004] In existing technologies, increasing the initial depth of the grooves is commonly used to extend the service life of polishing pads. However, this method has limited effect on improving service life, typically only extending it by 20% to 30%. At the same time, increasing the groove depth significantly increases the manufacturing difficulty of the polishing pad, placing higher demands on mold design, molding processes, and material consistency, thus posing significant process challenges. Furthermore, excessively deep groove structures may also cause problems such as polishing fluid leakage and exacerbated edge effects during polishing, affecting overall polishing performance.

[0005] Therefore, how to provide a polishing pad that can effectively extend the service life of the polishing pad without increasing the groove depth, while maintaining its stable polishing performance, remains a key research focus. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a chemical mechanical polishing pad with a long service life to solve the problems in the prior art.

[0007] To achieve the above and other related objectives, the present invention is obtained through the following technical solution.

[0008] A first aspect of this invention provides a long-life chemical mechanical polishing pad, the polishing pad comprising at least a polishing layer, the polishing layer comprising the following raw material components: polyurethane prepolymer, silicone modifier, expanded microspheres, and curing agent; the content of the silicone modifier is 0.05~8 wt% based on the total mass of the polyurethane prepolymer; the silicone modifier is selected from polydimethylsiloxane with multifunctional end groups, wherein the end groups are selected from one or more of amino, hydroxyl, and isocyanate groups. Preferably, the silicone modifier is selected from polydimethylsiloxane with multifunctional end groups, wherein the end groups are selected from one or more of amino and isocyanate groups. More preferably, the end groups are selected from amino groups.

[0009] Preferably, the polyurethane prepolymer is an isocyanate-terminated polyurethane prepolymer, which is generated by the reaction of polyisocyanate and polyol.

[0010] Specifically, the polyisocyanate can be toluene diisocyanate, diphenylmethane diisocyanate, or naphthalene diisocyanate; the polyol can be polytetramethylene ether glycol, polypropylene glycol, etc. The polyurethane prepolymers used in this application are common industrial chemicals and are commercially available, such as Imuthane™ prepolymers (supplied by COIM Inc., USA, with models PET-80A, PET-85A, PET-90A, PET-93A, PET-95A, PET-60D, PET-70D, PET-75D); and Adiprene™ prepolymers (supplied by Chemtura Inc., with models LF-800A, LF-900A, LF-910A, LF-930A, LF-931A, LF-939A, LF-950A, LF-952A, LF-600D, LF-601D, LF-650D, LF-667, LF-700D, LF-750D, LF-751D, LF-752D, LF-753D).

[0011] The polyurethane prepolymer used in this application is obtained by reacting toluene diisocyanate and / or diphenylmethane diisocyanate with polytetramethylene ether glycol.

[0012] Preferably, the NCO value of the polyurethane prepolymer is 5.0~12.5%. For example, it can be 5.0~10%, 6.0~10%, or 6.2~9.5%.

[0013] Preferably, the number average molecular weight of the organosilicon modifier is 200~10000 Da. For example, it can be 300~8000 Da, 500~5000 Da, 800~4000 Da, 840~3500 Da, or 1700~3500 Da, 2000~3000 Da, 840~1400 Da.

[0014] Specifically, when the end-capping group of the organosilicon modifier is amino, the organosilicon modifier is selected from one or more of the structures shown in the following schematic diagram:

[0015] Formula I: Where n is 1~135, as mentioned above, n can be 1~110, 1~100, 1~80, 1~60, 1~50, 10~30;

[0016] Formula II: Where n is 1 to 135, the structural formula of R can be: It can also be: As mentioned above, n can be 1~110, 1~100, 1~80, 1~60, 1~50, 10~50, or 20~40;

[0017] Formula III: , where n is 1~110, as mentioned above, n can be 1~100, 1~80, 1~60, 1~50, 10~50, 20~45.

[0018] Specifically, when the end group of the organosilicon modifier is a hydroxyl group, the organosilicon modifier is selected from one or more of the structures shown in the following schematic diagram:

[0019] Formula IV: Where n is 1~100, as mentioned above, n can be 1~80, 1~50, 1~40, or 10~30;

[0020] Formula V: Where n is 1~100, as mentioned above, n can be 1~80, 20~80, 30~70, or 30~60;

[0021] Formula VI: Where n is 1~100, as mentioned above, n can be 1~80, 20~80, 30~70, or 30~60.

[0022] Specifically, when the end-capping group of the organosilicon modifier is an isocyanate group, the organosilicon modifier is selected from one or more of the structures shown in the following schematic diagram:

[0023] Formula VII: , where n is 1~100, such as 1~80, 1~50, 1~40, 5~30, 1~20.

[0024] Preferably, the particle size of the expanded microspheres is 10~80μm. For example, it can be 10~70μm, 20~70μm, 20~60μm, or 30~50μm.

[0025] Preferably, the amount of expanded microspheres added is 0.3~5.0 wt% based on the total mass of the polyurethane prepolymer and the silicone modifier. For example, it can be 1~3 wt%, 1~2 wt%, or 0.8~2 wt%.

[0026] Preferably, the initial expansion temperature of the expanded microspheres is greater than 80°C.

[0027] This application does not limit the specific composition of the expanded microspheres, as long as they can achieve foaming and establish a microporous structure in the material. The expanded microspheres used in this application are hollow spheres with a core-shell structure. The shell is a thermoplastic material polymerized from acrylonitrile, methyl methacrylate, and vinylidene chloride, while the interior contains isobutane gas. Its industrial manufacturing includes polymerization, drying, and expansion steps. Expanded microspheres with diameters of approximately 20 μm and 40 μm are commonly used in the manufacture of polishing pads. For example, commercially available brands include Nouryon 461DET20D70, with a diameter of approximately 20 micrometers and a specific gravity of approximately 70 kg / m³. 3 And 551DE40D42, with a diameter of approximately 40 micrometers and a specific gravity of approximately 42 kg / m³. 3 Acquired through commercial purchase.

[0028] Preferably, the curing agent is an aromatic diamine compound, comprising one or more of 3,3'-dichloro-4,4'-diphenylmethane diamine (MOCA), 3,5-dimethylthiotoluene diamine (DMTDA), 3,5-diethyltoluene diamine (DETDA), 4,4'-methylenebis(3-chloro-2,6-diethylaniline) (M-CDEA), 4,4'-methylenebis(2,6-diethylaniline) (M-DEA), and 1,3-propanediol bis(4-aminobenzoate) (740M), more preferably MOCA. More specifically, the purity of the curing agent is greater than 90%.

[0029] Preferably, the amount of curing agent added is 15.0~35.0 wt%, based on the total mass of the polyurethane prepolymer and the silicone modifier. For example, it can be 15~32 wt%, 18~30 wt%, or 18.49~28.32 wt%.

[0030] Preferably, the polished layer includes one or more of the following features:

[0031] Thickness: 1.5~2.5 mm; Density: 0.700~0.900 g / cm³ 3 Hardness 40~80 Shore A; Abrasion test was conducted using a TABLE abrasion tester with a load of 1~2kg and a speed of 70~95rpm for 1~3 hours, with the wear amount not exceeding 350mg.

[0032] The thickness can be 1.8~2.0 mm or 1.8~2.2 mm; the density can be 0.750~0.850 g / cm³. 3 0.792~0.850 g / cm³ 3 0.792~0.825g / cm 3 0.815~0.825g / cm 3 The hardness can be 45~70 Shore A, 45~65 Shore A, or 49~64 Shore A; the wear amount can be 156~234 mg, 120~350 mg, 140~350 mg, or 156~340 mg.

[0033] Preferably, the polishing pad further includes a buffer layer disposed at the bottom of the polishing layer; the buffer layer is prepared using a polymer material with shock-absorbing properties. Specifically, the polymer material with shock-absorbing properties can be a non-woven polyurethane material, a porous polyurethane foam, a porous ethylene-vinyl acetate copolymer, a porous silicone material, etc.

[0034] Preferably, the bottom of the polishing pad is a bottom adhesive layer; the bottom adhesive layer is a double-sided pressure-sensitive adhesive.

[0035] Preferably, the thickness of the buffer layer is 0.8~2.0 mm. For example, it can be 0.8~1.8 mm or 1.0~1.5 mm.

[0036] A second aspect of the present invention provides a method for preparing a long-life chemical mechanical polishing pad as described above, comprising the following steps:

[0037] 1) The polyurethane prepolymer is contacted with the organosilicon modifier to carry out a first reaction to obtain a modified prepolymer;

[0038] 2) After adding expanded microspheres to the modified prepolymer for a second treatment, a curing agent is added for curing treatment to obtain the polished layer.

[0039] Preferably, the first reaction includes one or more of the following conditions:

[0040] The temperature of the first reaction is 60~90℃;

[0041] The first reaction is carried out under a protective gas, which includes nitrogen.

[0042] The time for the first reaction is 1 to 3 hours.

[0043] For example, the temperature of the first reaction can be 70~80℃ or 72~78℃; the time of the first reaction can be 1h, 2h or 3h.

[0044] Preferably, the foaming treatment includes one or more of the following conditions:

[0045] Add expanded microspheres under vacuum conditions;

[0046] The temperature for the second treatment is 40~90℃;

[0047] The pressure for the second treatment is 0.01~2.00 MPa;

[0048] The second processing time is 1-3 hours.

[0049] For example, the temperature of the second reaction can be 40~80℃, 40~60℃, or 45~55℃; the time of the second reaction can be 1h, 2h, or 3h; and the pressure of the second reaction can be 0.01~1.5 MPa, 0.01~1.0 MPa, 0.01~0.5 MPa, or 0.01~0.1 MPa.

[0050] Preferably, the curing temperature is 100~120℃ and the time is 16~20h. For example, the curing temperature can be 105~115℃ or 110℃; the time can be 16h, 18h or 20h.

[0051] Preferably, after the curing process, the polishing surface of the polishing layer is subjected to one or more processes selected from slicing, surface sanding, and grooving.

[0052] Preferably, a buffer layer is provided, and the polishing layer and the buffer layer are bonded together. This application does not specifically limit the bonding method; it can be achieved using one or more of pressure-sensitive adhesives, hot melt adhesives, and reactive hot melt adhesives.

[0053] A third aspect of the present invention provides an application of the long-life chemical mechanical polishing pad described above in chemical mechanical polishing.

[0054] Preferably, the chemical mechanical polishing pad is used as a polishing pad for polishing silicon oxide wafers in chemical mechanical polishing. Beneficial effects:

[0055] This application provides a specific polishing pad by adding a specific type and amount of organosilicon modifier, combined with other technical means. When used for rough polishing of silicon oxide wafers, this polishing pad exhibits a high removal rate, resulting in high-quality wafer surface with few scratches. Furthermore, the polishing pad has high hardness and good wear resistance, thus minimizing wear on the grooves during use and extending its service life. Attached Figure Description

[0056] Figure 1 The image shows scratches on the wafer surface after polishing with a commercially available polishing pad.

[0057] Figure 2 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Embodiment 1 of the present invention.

[0058] Figure 3 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Comparative Example 1 of this invention.

[0059] Figure 4 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Embodiment 2 of the present invention.

[0060] Figure 5 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Embodiment 3 of the present invention.

[0061] Figure 6 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Comparative Example 5 of this invention.

[0062] Figure 7 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Embodiment 4 of the present invention.

[0063] Figure 8 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Embodiment 5 of the present invention.

[0064] Figure 9 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Embodiment 6 of the present invention.

[0065] Figure 10 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Embodiment 7 of the present invention.

[0066] Figure 11 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Embodiment 8 of the present invention.

[0067] Figure 12 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Embodiment 9 of the present invention.

[0068] Figure 13 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Comparative Example 2 of this invention.

[0069] Figure 14 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Embodiment 10 of the present invention.

[0070] Figure 15 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Embodiment 11 of the present invention.

[0071] Figure 16 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Comparative Example 3 of this invention.

[0072] Figure 17 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Embodiment 12 of the present invention.

[0073] Figure 18 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Embodiment 13 of the present invention.

[0074] Figure 19 The image shown is a scratch pattern on the surface of a wafer after polishing using the polishing pad provided in Comparative Example 4 of this invention.

[0075] Figure 20 The graph shows the cut rate statistics after polishing using the polishing pads provided in the embodiments and comparative examples of this invention. Detailed Implementation

[0076] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0077] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the respective manufacturers.

[0078] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. In addition to the specific methods, apparatus, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description of this invention, any prior art methods, apparatus, and materials similar to or equivalent to those described, apparatus, and materials in the embodiments of this invention may be used to implement the present invention.

[0079] This application provides a method for introducing organosilicon modifiers containing specific silicon-oxygen bonds. By controlling their content and combining them with other technical means, the polishing pads provided by this application have a long service life and good polishing effect. This is partly because the introduction of specific organosilicon modifiers enhances the rigidity of the molecular chains, making the molecules less prone to breakage or detachment, thus delaying wear on the surface of the polishing pad. On the other hand, it can form a low-friction lubricating film on the surface of the polishing pad, reducing direct micro-protrusion contact and adhesive wear between the polishing pad and the wafer / polishing fluid, thereby reducing friction on the polishing pad itself and increasing its service life. In this application, the applicant discovered that organosilicon modifiers with different specific structures can significantly improve the wear resistance of the polishing pad, and the degree of improvement in wear resistance varies depending on the organosilicon modifier with different end groups. Specifically, when the end group of the organosilicon modifier is hydroxyl, its improvement on the wear resistance of the polishing pad is the weakest, while when the end group of the organosilicon modifier is amino, its improvement on the wear resistance of the polishing pad is the best, followed by isocyanate groups. This is closely related to the reactivity of the end-capping groups, interfacial compatibility, and the strength of the chemical bonds formed.

[0080] When using an organosilicon modifier with an amino end group, it forms the strongest and most stable covalent bond with the polyurethane prepolymer (the amino group can form a urea bond with the isocyanate in the polyurethane prepolymer), thus allowing the organosilicon modifier to bind tightly with the polyurethane prepolymer and preventing its migration and precipitation. At the same time, the amino group is a strongly polar group, which helps to improve the compatibility between the organosilicon modifier and the polyurethane prepolymer, making its dispersion more uniform and improving the overall wear resistance of the polishing pad.

[0081] When using organosilicon modifiers with isocyanate end groups, they can also form covalent bonds with polyurethane prepolymers. However, isocyanate groups react readily with water, leading to bubble defects. Furthermore, isocyanate groups are prone to self-polymerization, resulting in uneven crosslinking during the reaction. Consequently, the polishing pads produced have uneven hardness, with some areas becoming brittle or too soft. This makes the wear resistance of the polishing pads inferior to those with amino-terminated organosilicon modifiers.

[0082] When using organosilicon modifiers with hydroxyl end groups, although they can improve the wear resistance of polishing pads to some extent, the urethane bonds formed by hydroxyl groups and polyurethane prepolymers are far less energetic than urea bonds compared to amino groups, making them more prone to breakage and loss. Moreover, compared to isocyanate groups, hydroxyl groups have lower reactivity, resulting in fewer covalent bonds and a lower degree of crosslinking. At the same time, the polarity of hydroxyl groups is weak, which is insufficient to improve the compatibility between organosilicon modifiers and polyurethane prepolymers, making them prone to phase separation and weak interfaces, and easily generating microcracks and wear during friction.

[0083] The first polyurethane prepolymer used in the following embodiments of this application is branded by Chemtura and model number Adiprene LF-750D; the second polyurethane prepolymer is branded by COIM and model number Imuthane™ PET-75D; the third polyurethane prepolymer is branded by COIM and model number Imuthane™ PET-95A; the expanded microspheres are branded by Noryon and model number Expansionl 551DE40D42 with a particle size of 40μm; and the curing agent has a purity of 99.7%.

[0084] Example 1

[0085] This embodiment provides a specific chemical mechanical polishing pad and its preparation method. The raw material components of the chemical mechanical polishing pad are as follows: a first polyurethane prepolymer (NCO value of 9.1%), an organosilicon modifier: double-terminated hydroxyl PDMS, whose molecular structure is formula IV and molecular weight is 1700 g / mol (n=21), expanded microspheres, and curing agent MOCA; the mass ratio of the first polyurethane prepolymer to the organosilicon modifier is 100:1.

[0086] Includes the following steps:

[0087] 1) Under a nitrogen atmosphere and at 75°C, the first polyurethane prepolymer and the organosilicon modifier are mixed for 2 hours to undergo a first reaction to obtain a modified prepolymer.

[0088] 2) Add the expanded microspheres (the mass ratio of modified prepolymer to expanded microspheres is 100:1.5) to the modified prepolymer, stir and mix for 2 hours under vacuum conditions of 51℃ and 0.06MPa, then add the curing agent MOCA (the mass ratio of modified prepolymer to MOCA is 100:27.13), and cure at 110℃ for 18 hours to obtain a polished block;

[0089] 3) After cutting the polishing block into thin slices with a thickness of 2mm, the surface is sanded with sandpaper of 160 grit, so that the roughness Ra after sanding is 1.0μm; then, a CNC machine is used to process the polished surface into the required groove shape (such as a square groove), with a groove width of 1mm and a groove depth of 1mm, to obtain the polishing layer;

[0090] 4) A layer of double-sided pressure-sensitive adhesive is bonded to the non-grooved surface of the polishing layer to obtain the polishing pad.

[0091] Example 2

[0092] The amount of raw material components of the chemical mechanical polishing pad is modified as follows: the mass ratio of the first polyurethane prepolymer to the organosilicon modifier is 100:0.05, and the remaining steps are exactly the same as in Example 1.

[0093] Example 3

[0094] The amount of raw material components of the chemical mechanical polishing pad is modified as follows: the mass ratio of the first polyurethane prepolymer to the organosilicon modifier is 100:5, and the remaining steps are exactly the same as in Example 1.

[0095] Example 4

[0096] In the raw material composition of the chemical mechanical polishing pad, the type of organosilicon modifier is modified to double-terminated hydroxyl PDMS, which has the molecular structure of formula V and a molecular weight of 3500 g / mol (n=46). The remaining steps are exactly the same as in Example 1.

[0097] Example 5

[0098] In the raw material composition of the chemical mechanical polishing pad, the type of organosilicon modifier is modified to double-terminated amino PDMS, which has the molecular structure of Formula I and a molecular weight of 2000 g / mol (n=24). The remaining steps are exactly the same as in Example 1.

[0099] Example 6

[0100] In the raw material composition of the chemical mechanical polishing pad, the type of organosilicon modifier is modified to double-terminated amino PDMS, which has the molecular structure of Formula II and a molecular weight of 3000 g / mol (n=38). The remaining steps are exactly the same as in Example 1.

[0101] Example 7

[0102] In the raw material composition of the chemical mechanical polishing pad, the type of organosilicon modifier is modified to double-terminated isocyanate oxydimethyl PDMS, which has the molecular structure of formula VII and an NCO value of 3%. The remaining steps are exactly the same as in Example 1.

[0103] Example 8

[0104] In the raw material composition of the chemical mechanical polishing pad, the type of organosilicon modifier is modified to double-terminated isocyanate oxydimethyl PDMS, with a molecular structure of formula VII and an NCO value of 5%. The remaining steps are exactly the same as in Example 1.

[0105] Example 9

[0106] The raw material composition of the chemical mechanical polishing pad is as follows: a second polyurethane prepolymer (NCO value of 9.5%), an organosilicon modifier: PDMS with double-terminated hydroxyl groups and a molecular weight of 1700 g / mol, expanded microspheres, and a curing agent MOCA; the mass ratio of the second polyurethane prepolymer to the organosilicon modifier is 100:1; and in step 2), when the curing agent MOCA is added, the mass ratio of the modified prepolymer to MOCA is 100:28.32, and the remaining steps are exactly the same as in Example 1.

[0107] Example 10

[0108] In the raw material composition of the chemical mechanical polishing pad, the type of organosilicon modifier is modified to double-terminated amino PDMS, which has the molecular structure of Formula I and a molecular weight of 2000 g / mol. The remaining steps are exactly the same as in Example 9.

[0109] Example 11

[0110] The raw material composition of the chemical mechanical polishing pad is as follows: a third polyurethane prepolymer (NCO value of 6.2%), an organosilicon modifier: double-terminated hydroxyl PDMS with molecular structure of formula V and molecular weight of 3500 g / mol, expanded microspheres, and a curing agent MOCA; the mass ratio of the third polyurethane prepolymer to the organosilicon modifier is 100:1; and in step 2), when the curing agent MOCA is added, the mass ratio of the modified prepolymer to MOCA is 100:18.49, and the remaining steps are exactly the same as in Example 1.

[0111] Example 12

[0112] In the raw material composition of the chemical mechanical polishing pad, the type of organosilicon modifier is modified to double-terminated amino PDMS, which has the molecular structure of Formula III and a molecular weight of 3000 g / mol (n=38). The remaining steps are exactly the same as in Example 11.

[0113] Example 13

[0114] The raw material composition of the chemical mechanical polishing pad is as follows: a first polyurethane prepolymer (NCO value of 9.1%) and a second polyurethane prepolymer (NCO value of 9.5%) (mass ratio of 1:1), an organosilicon modifier: dihydroxyl-terminated PDMS, whose molecular structure is Formula I and molecular weight is 1700 g / mol, expanded microspheres, and a curing agent MOCA; the total mass ratio of the first polyurethane prepolymer and the third polyurethane prepolymer to the organosilicon modifier is 100:1; and in step 2), when the curing agent MOCA is added, the mass ratio of the modified prepolymer to MOCA is 100:27.72, and the remaining steps are exactly the same as in Example 1.

[0115] Comparative Example 1

[0116] This comparative example is the same as Example 1, except that no organosilicon modifier is added; all other steps are the same.

[0117] Comparative Example 2

[0118] This comparative example is the same as Example 9, except that no organosilicon modifier is added; all other steps are the same.

[0119] Comparative Example 3

[0120] This comparative example is the same as Example 11, except that no organosilicon modifier is added, and the other steps are the same.

[0121] Comparative Example 4

[0122] This comparative example is the same as Example 13, except that no organosilicon modifier is added, and the other steps are the same.

[0123] Comparative Example 5

[0124] This comparative example is the same as Example 1, except that the mass ratio of the first polyurethane prepolymer to the silicone modifier is 100:10 and a silicone modifier is added; the other steps are the same.

[0125] The applicant conducted performance tests on the polished layers provided in Examples 1-13 and Comparative Examples 1-5, specifically,

[0126] Density: The sample after abrasion was punched into a circle with a diameter of 10 cm. Its mass m was measured using an analytical balance (0.0001 g accuracy), and its thickness h was measured using a thickness gauge (0.001 mm accuracy). The density was calculated using the formula density = m / (3.145 * 5 * 5 * h / 10), with units of g / cm³. 3 .

[0127] Hardness: This indicator refers to Shore hardness, also known as Shore scale hardness, or Shore scale hardness. It is a method for expressing the hardness grade of metals, plastics, and rubber materials. Hardness is the ability to resist indentation by an external force; its numerical value reflects the degree of softness or hardness of the material. When measured with a Shore hardness tester, the indenter of the hardness tester is pressed against the surface of the sample, and the depth of indentation is measured. In this example, a type D (indicating) hardness tester was used for measurement.

[0128] Abrasion: The abrasion resistance of different samples was evaluated using a TABLE abrasion tester. Samples were prepared as 2mm thick discs, cut into 110mm diameter round pieces, fixed on the TABLE abrasion tester, with a counterweight of 1500g, a pulse rate of 84RPM, and an abrasion time of 2 hours. The weight difference (mg) of the sample before and after the test was calculated; this value is the abrasion value. A lower abrasion value indicates better abrasion resistance.

[0129] The specific test results are shown in Table 1.

[0130] Table 1

[0131]

[0132] As shown in Table 1, the density of the polishing pad provided by this application is 0.792~0.825 g / cm³. 3 It has a hardness of 49~65 Shore D and an abrasion rate of 156~340 mg.

[0133] As can be seen from Comparative Example 1 and Example 1, with almost the same hardness and density, the polished layer provided in Comparative Example 1 has an abrasion of 388 mg under the same conditions, which is much higher than the 322 mg of Example 1.

[0134] As can be seen from Comparative Example 2 and Example 9, with almost the same hardness and density, the polished layer provided in Comparative Example 2 has a wear of 366 mg under the same conditions, which is significantly higher than the 331 mg of Example 9.

[0135] As can be seen from Comparative Example 3 and Example 11, with almost the same hardness and density, the polished layer provided in Comparative Example 3 has a wear of 312 mg under the same conditions, which is significantly higher than the 282 mg of Example 11.

[0136] As can be seen from Comparative Example 4 and Example 13, with almost the same hardness and density, the polished layer provided in Comparative Example 4 has a wear of 423 mg under the same conditions, which is much higher than the 248 mg of Example 13.

[0137] This indicates that the technical solution of this application effectively improves the wear resistance of the polishing layer by mixing a specific organosilicon modifier with other technical means, resulting in better wear resistance of the polishing layer under the same wear environment, thereby enabling it to have a longer service life.

[0138] Meanwhile, as can be seen from Examples 1-3 and Comparative Example 5, the amount of silicone modifier added in this application is specific. Within the scope of this application, the wear of the polished layer decreases as the amount added increases. However, the content of the silicone modifier cannot be too high. If the content of the added silicone modifier is too high, the product hardness will be significantly reduced, and the wear performance will be significantly worsened.

[0139] As can be seen from Examples 1, 5-6, and 7-8, the end-capping groups of the organosilicon modifier in this application affect the wear resistance of the final polishing pad. When the end-capping group of the organosilicon modifier is amino, the corresponding polishing pad has good wear resistance; when the end-capping group of the organosilicon modifier is isocyanate oxy, it is next; and when hydroxyl is used, the corresponding polishing pad shows the least improvement in wear resistance.

[0140] The applicant also conducted polishing performance tests on the polishing pads provided by DuPont IC1000, which are commercially available in Examples 1-13, Comparative Examples 1-5, and the prior art. Specifically:

[0141] The object being polished was a silicon oxide wafer, specifically a TEOS oxide wafer (TEOS stands for tetraethoxysilane) formed by chemical vapor deposition. The equipment used was a Huahai Qingke machine, with Anji D2000E (1:1 diluted) as the polishing slurry. A Saesol Disk was used, and the rotation speed was set to 93 / 87 r / min (disk surface / polishing head surface). The polishing slurry flow rate was set to 250 ml / min, the polishing pressure was set to 3.5 psi, and the polishing time was 60 s.

[0142] The specific results are shown in Table 2.

[0143] The Cut rate, calculated by dividing the groove depth decrease by the polishing time, represents the wear rate of the groove depth. A lower rate is better, indicating a longer polishing pad lifespan. Cut rate data was obtained by continuously abrading the pad using a Saesol AK45 disk at a speed of 93:100 r / min (disk surface / disk) under DIW conditions for 2 hours, simulating aging. The groove depth was then measured using a depth gauge (Mitutoyo ABSOLUTE digital depth 547-252 model, accuracy 0.001 mm) to obtain the groove change data. Cut rate statistics for various embodiments and comparative examples are shown in the attached graphs. Figure 20 .

[0144] The method for testing the removal rate (MRR) is as follows: the film thickness before and after wafer polishing is measured using a film thickness gauge, and the difference is divided by the polishing time to obtain the MRR, which is expressed in Å / min and represents the efficiency of the polishing process.

[0145] After polishing, scanning electron microscopy (SEM) was used to observe and record the surface scratches on the wafer to evaluate the surface quality of the polished wafer. Specific results are shown in [link to SEM]. Figures 1-19 .

[0146] Table 2

[0147]

[0148] Note: XXX indicates many scratches (more than 100 scratches, very obvious); XX indicates a lot of scratches (50-99 scratches, obvious); X indicates scratches (20-49 scratches); OOO indicates no scratches; OO indicates almost no scratches (less than 5 scratches, shallow); O indicates few scratches (6-19 scratches, shallow).

[0149] From Table 2 and Figures 1-20 It is known that the polishing layer provided by this application has an MRR of 2877~3921 Å / min and a low cut rate of 10.2~37.2μm / h when used for polishing oxide wafers. Moreover, the surface quality after polishing is good and there are few surface scratches. Compared with DuPont IC1000, the polishing pad of this application has a lower cut rate when polishing, and therefore a longer service life, while the MRR is not much different.

[0150] As can be seen from Comparative Example 1 and Example 1, with almost identical MRR and Cut rate, compared to the embodiments of this application, the polishing pad in Comparative Example 1 produces a poorer surface quality after polishing, with more scratches (see Comparative Example 1). Figure 2 and Figure 3 Furthermore, its high cut rate leads to significant wear on the grooves, resulting in a shorter lifespan for the polishing pad. As shown in Comparative Example 5 and Example 1, compared to Example 1, when using the polishing pad provided in Comparative Example 5, the removal rate decreases, the polishing efficiency is low, and the high cut rate leads to significant wear on the grooves and a short lifespan for the polishing pad. This indicates that the amount of organosilicon modifier added in the technical solution of this application affects the polishing effect and lifespan of the polishing pad.

[0151] As can be seen from Comparative Example 2 and Example 9, compared with the embodiments of this application, under the condition of almost the same removal rate, the cut rate in Comparative Example 2 is higher, resulting in greater wear on the grooves, thus leading to a shorter service life of the polishing pad. Furthermore, the surface quality after polishing is significantly worse, with numerous scratches appearing (see...). Figure 12 and Figure 13 As can be seen from Comparative Example 3 and Example 11, compared with the embodiments of this application, the polishing pad provided in Comparative Example 3 has a higher cut rate when used for polishing, but it suffers from large groove wear, short polishing pad life, and poor surface quality after polishing, with more scratches (see Comparative Example 3). Figure 15 and Figure 16 As can be seen from Comparative Example 4 and Example 13, compared with the embodiments of this application, the polishing pad provided in Comparative Example 4 has a significantly increased cutrate when used for polishing. This results in significant groove wear, severely shortened service life, and poor surface quality after polishing, with numerous scratches (see Comparative Example 4). Figure 18 and Figure 19 This indicates that the use of the silicone modifier in this application is specific; without the silicone modifier, the lifespan of the polishing pad would be significantly shortened, and the surface quality after polishing would also be significantly reduced.

[0152] As shown in Examples 1, 5-6, and 7-8, the end-capping groups of the silicone modifier significantly affect the lifespan of the polishing pad. Compared to Example 1, when using the silicone modifiers in Examples 5-6 (end-capping group is amino) and Examples 7-8 (end-capping group is isocyanate oxy), the cut rate is lower, and the wear on the trenches is less, thus significantly improving the lifespan of the polishing pad. This indicates that when the end-capping group of the silicone modifier is amino, the effect on improving the lifespan of the polishing pad is the best, followed by isocyanate oxy, and hydroxyl is the worst.

[0153] In summary, the polishing pad provided by this application has a fast removal rate and high polishing efficiency when applied to polishing, and the surface quality after polishing is good with almost no scratches; in addition, the polishing pad provided by this application has a longer service life.

[0154] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A chemical mechanical polishing pad with a long service life, characterized in that, The polishing pad includes at least a polishing layer, which comprises the following raw material components: polyurethane prepolymer, silicone modifier, expanded microspheres, and curing agent; the content of the silicone modifier is 0.05~8 wt% based on the total mass of the polyurethane prepolymer; the silicone modifier is selected from polydimethylsiloxane with multifunctional end groups selected from one or more of amino, hydroxyl, and isocyanate groups.

2. The chemical mechanical polishing pad according to claim 1, characterized in that, The polyurethane prepolymer is an isocyanate-terminated polyurethane prepolymer, which is generated by the reaction of polyisocyanate and polyol. And / or, the NCO value of the polyurethane prepolymer is 5.0~12.5%; And / or, the number average molecular weight of the organosilicon modifier is 200~10000 Da.

3. The chemical mechanical polishing pad according to claim 2, characterized in that, When the end-capping group of the organosilicon modifier is amino, the organosilicon modifier is selected from one or more of the structures shown in the following schematic diagram: Formula I: , where n is 1 to 135; Formula II: Where n is 1~135, and the structural formula of R includes and One or more of the following; Formula III: , where n is 1 to 110; And / or, when the end-capping group of the organosilicon modifier is hydroxyl, the organosilicon modifier is selected from one or more of the structures shown in the following schematic diagram: Formula IV: , where n is 1 to 100; Formula V: Where n is 1 to 100; Formula VI: Where n is 1 to 100; And / or, when the end-capping group of the organosilicon modifier is an isocyanate group, the organosilicon modifier is selected from one or more of the structures shown in the following schematic diagram: Formula VII: , where n is 1 to 100.

4. The chemical mechanical polishing pad according to claim 1, characterized in that, The particle size of the expanded microspheres is 10~80μm; And / or, the initial expansion temperature of the expanded microspheres is greater than 80°C; And / or, based on the total mass of the polyurethane prepolymer and the silicone modifier, the amount of the expanded microspheres added is 0.3~5.0 wt%; The curing agent is an aromatic diamine compound, comprising one or more of 3,3'-dichloro-4,4'-diphenylmethane diamine, 3,5-dimethylthiotoluene diamine, 3,5-diethyltoluene diamine, 4,4'-methylenebis(3-chloro-2,6-diethylaniline), 4,4'-methylenebis(2,6-diethylaniline), and 1,3-propanediolbis(4-aminobenzoic acid ester); And / or, based on the total mass of the polyurethane prepolymer and the silicone modifier, the amount of curing agent added is 15.0~35.0 wt%.

5. The chemical mechanical polishing pad according to claim 1, characterized in that, The polished layer includes one or more of the following features: Thickness is 1.5~2.5 mm; Its density is 0.700~0.900 g / cm³. 3 ; Hardness 40~80 Shore A; The wear tester was used to test the wear of 1-2 kg of weight at 70-95 rpm for 1-3 hours, and the wear amount was not higher than 350 mg. And / or, the polishing pad further includes a buffer layer disposed at the bottom of the polishing layer; And / or, the bottom of the polishing pad is a bottom adhesive layer; the bottom adhesive layer is a double-sided pressure-sensitive adhesive.

6. The chemical mechanical polishing pad according to claim 5, characterized in that, The thickness of the buffer layer is 0.8~2.0mm.

7. A method for preparing a long-service-life chemical mechanical polishing pad as described in any one of claims 1 to 6, characterized in that, Includes the following steps: 1) The polyurethane prepolymer is contacted with the organosilicon modifier to carry out a first reaction to obtain a modified prepolymer; 2) After adding expanded microspheres to the modified prepolymer for a second treatment, a curing agent is added for curing treatment to obtain the polished layer.

8. The preparation method according to claim 7, characterized in that, The first reaction includes one or more of the following conditions: The temperature of the first reaction is 60~90℃; The first reaction is carried out under a protective gas, which includes nitrogen. And / or, the second process includes one or more of the following conditions: Add expanded microspheres under vacuum conditions; The temperature for the second treatment is 40~90℃; The pressure for the second treatment is 0.01~2.00MPa.

9. The preparation method according to claim 7, characterized in that, The curing temperature is 100~120℃; And / or, after the curing process, the polished surface of the polished layer is subjected to one or more of the following processes: slicing, surface sanding, and grooving. And / or, a buffer layer is provided, wherein the polishing layer and the buffer layer are bonded together.

10. The application of the chemical mechanical polishing pad according to any one of claims 1 to 6 in chemical mechanical polishing.

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