Method for manufacturing a window for a polishing pad and a polishing pad window manufactured by this method

Abstract

The present invention provides a method for manufacturing a window for a polishing pad, the method comprising the steps of: a) mixing a polyurethane prepolymer having a temperature of 50°C or more and less than 100°C with a curing agent to prepare a mixture; b) injecting the mixture into a mold heated to a temperature of 30°C or more and less than 100°C to a thickness of 5 mm or less; c) demolding the cured polyurethane from the mold; and d) processing the cured polyurethane to a thickness of a window for a polishing pad; and a window for a polishing pad manufactured by the method, and a polishing pad including the window.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0008594, filed on January 20, 2022, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a method for manufacturing a window for a polishing pad and a window for a polishing pad manufactured by this method. [Background technology]

[0003] Chemical Mechanical Planarization / Polishing (hereinafter referred to as CMP) is a process introduced for global planarization of semiconductor devices, and is becoming an increasingly important process due to the trend toward larger wafer diameters, higher integration, finer line widths, and multi-layered wiring structures.

[0004] In the CMP process, the polishing rate and flatness are important, and these are determined by the process conditions of the polishing equipment and the consumables, the polishing slurry and the polishing pad, used. In particular, the polishing pad functions to uniformly distribute the polishing slurry supplied in contact with the wafer surface onto the wafer, and to perform a physical removal action by the abrasive particles in the polishing slurry and the surface protrusions of the polishing pad.

[0005] Generally, a polishing pad includes a polishing layer (10), a window (20) formed in the polishing layer, and a lower support layer (30), which has an opening (22) formed in the lower support layer (30) below the window, as shown in Figure 1. The polishing layer and the lower support layer are bonded together by an adhesive layer (40).

[0006] The window is formed to detect the polishing endpoint of a wafer in a CMP process, and the detection is performed by transmitting an optical beam, such as a laser beam, through the window. Therefore, the window must have a transmittance in a specific range that allows the optical beam to pass through.

[0007] However, conventional windows have the drawback that they do not have sufficient transmittance to allow optical beams to pass through them, making it difficult to accurately and reliably detect the polishing endpoint of a wafer in a CMP process. Therefore, there is a need to develop windows with improved transmittance. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Korean Patent Publication No. 10-2001-2696 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention was discovered in order to solve the above-mentioned problems of the prior art, and its object is to provide a method for manufacturing a window for a polishing pad that can efficiently manufacture a window having excellent transmittance.

[0010] Another object of the present invention is to provide a window for a polishing pad, which has excellent transmittance and can accurately and reliably detect the polishing end point of a wafer, and a polishing pad including the same. [Means for solving the problem]

[0011] In order to achieve the above object, the present invention provides a) 50°C or 70°C mixing a polyurethane prepolymer having a temperature of 0.15 to 0.50 and a curing agent to form a mixture; b) Heat the mixture at 30℃ or 60°C In a mold heated to a temperature of 2mm to 3mminjection stage with a thickness of; c) releasing the cured polyurethane from the mold; and d) processing the cured polyurethane into a thickness of a window of a polishing pad; fruit, The polyurethane prepolymer is produced by polymerization of a composition containing one or more isocyanate compounds selected from the group consisting of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, naphthalene-1,5-diisocyanate, toluidine diisocyanate, paraphenylene diisocyanate, xylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and cyclohexane diisocyanate, and one or more polyol compound components selected from the group consisting of polyether polyol, polycarbonate polyol, polyester polyol, and polycaprolactone polyol. A method for manufacturing a window for a polishing pad is provided.

[0012] The present invention also provides before Record Window teeth , based on a thickness of 1.9 mm With 670nm light Polishing pad window with transmittance of 5% or more Manufacturing method to provide. [Effects of the Invention]

[0014] The method for manufacturing a window for a polishing pad of the present invention provides a method for efficiently manufacturing a window having excellent transmittance. Furthermore, the polishing pad window of the present invention and the polishing pad including the same have improved transmittance, making it possible to accurately and reliably detect the polishing endpoint of a wafer. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a cross-sectional view showing a typical polishing pad configuration including a window. [Figure 2] FIG. 2 is a graph showing the results of measuring the transmittance of the polishing pad window of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings so that those skilled in the art can easily understand the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. The same reference numerals are used throughout the specification to refer to similar parts.

[0017] In the present invention, the meaning of "comprises" means that other components may be included in addition to the specific components included, but it may also mean that the product is composed of only the specific components without any other components.

[0018] The method for producing a polishing pad window of the present invention comprises the steps of: a) mixing a polyurethane prepolymer having a temperature of 50°C or more and less than 100°C with a curing agent to prepare a mixture; b) pouring the mixture into a mold heated to a temperature of 30°C or more but less than 100°C to a thickness of 5 mm or less; c) releasing the cured polyurethane from the mold; and d) processing the cured polyurethane into a thickness of a window of a polishing pad.

[0019] The present inventors have discovered that the transmittance of a window made of polyurethane material varies depending on the heat generation control during curing and the manufacturing method, and have completed the present invention.

[0020] Specifically, the present inventors discovered that in the production of a polyurethane material window, the temperature of the polyurethane prepolymer and the temperature of the mold affect the transmittance of the window, and that the thickness of the cake-like cured polyurethane also affects the transmittance of the window, and thus completed the present invention.

[0021] In step a), if the temperature of the polyurethane prepolymer is between 50°C and 100°C, the transmittance of the window is significantly improved. However, if the temperature is below 50°C or above 100°C, the transmittance of the window is significantly reduced.

[0022] The reason why the transmittance of the polyurethane prepolymer decreases with temperature is believed to be that the crystallinity of the internal structure of the urethane increases as the temperature increases. In one embodiment of the present invention, the temperature of the polyurethane prepolymer may be preferably 50 to 90°C, more preferably 50 to 70°C.

[0023] In the step a), the polyurethane prepolymer may have a weight average molecular weight of 500 to 3,000, more preferably 800 to 2,500.

[0024] The polyurethane prepolymer can be produced by polymerizing a composition containing one or more isocyanate compounds selected from the group consisting of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, naphthalene-1,5-diisocyanate, toluidine diisocyanate, paraphenylene diisocyanate, xylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and cyclohexane diisocyanate, and one or more polyol compound components selected from the group consisting of polyether polyols (e.g., poly(oxytetramethylene) glycol, poly(oxypropylene) glycol, poly(oxyethylene) glycol), polycarbonate polyols, polyester polyols, and polycaprolactone polyols.

[0025] The isocyanate compound is preferably selected from toluene diisocyanate (TDI), 4,4'-diphenyl methane diisocyanate, dicyclohexylmethane diisocyanate, etc., and the polyol compound is preferably selected from polycaprolactone polyol, polytetramethylene ether glycol (PTMEG), polypropylene ether glycol (PPG), polyethylene ether glycol (PEG), etc.

[0026] The polymeric composition may further include one or more chain extenders selected from the group consisting of ethylene glycol (EG), 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol (BDO), neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, tripropylene glycol, and the like.

[0027] Examples of the curing agent in step a) include 4,4'-methylenebis(2-chloroaniline) (MBOCA), diethyltoluenediamine (DETDA), 3,5-dimethylthio-2,4-toluenediamine and its isomers; 3,5-diethyltoluene-2,4-diamine and its isomers (e.g., 3,5-diethyltoluene-2,6-diamine); 4,4'-bis(sec-butylamino)-diphenylmethane; 1,4-bis(sec-butylamino)-benzene; 4,4'-methylenebis(2-chloroaniline); 4,4'-methylenebis(3-chloro-2,6-diethylaniline) (MCDEA); polytetrafluoroethylene (PTFE); One or more selected from the group consisting of tramethylene oxide-di-p-aminobenzoate; N,N'-dialkyldiaminodiphenylmethane; p,p'-methylenedianiline (MDA); m-phenylenediamine (MPDA); 4,4'-methylenebis(2,6-diethylaniline) (MDEA); 4,4'-methylenebis(2,3-dichloroaniline) (MDCA); 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane; 2,2',3,3'-tetrachlorodiaminodiphenylmethane; and trimethylene glycol di-p-aminobenzoate can be used.

[0028] In step a), the polyurethane prepolymer and the curing agent may be mixed in a weight ratio of 9:1 to 7:3 on a dry weight basis.

[0029] In step b), the mold used is heated to a temperature of 30°C or higher but lower than 100°C. If the mold temperature is lower than 30°C, the transmittance improves, but the polyurethane does not harden, making it difficult to apply to the present invention. Furthermore, if the mold temperature is higher than 100°C, the transmittance of the window drops significantly, which is undesirable.

[0030] As mentioned above, when the mold temperature is 100° C. or higher, the transmittance decreases, presumably because the crystallinity of the internal structure of the urethane increases as the mold temperature increases.

[0031] In one embodiment of the present invention, the temperature of the mold is preferably 30°C to 80°C, more preferably 30°C to 70°C, even more preferably 30°C to 60°C, and particularly preferably 30°C to 50°C.

[0032] The polyurethane prepolymer and curing agent mixture can be injected into the mold in step b) to a thickness of 5 mm or less, since if the injection thickness exceeds 5 mm, the transmittance of the window will be significantly reduced.

[0033] The reason why the transmittance decreases depending on the injection thickness is thought to be that as the injection thickness increases, thermal energy accumulates during the exothermic reaction with the curing agent, causing the internal temperature to rise and the degree of crystallinity to increase.

[0034] In one embodiment of the present invention, the thickness of the implant may be preferably 2 mm to 5 mm, more preferably 2 mm to 4 mm, and even more preferably 2 mm to 3 mm.

[0035] When the mixture is poured to the above thickness, the thickness of the polyurethane cake is determined by the pouring thickness.

[0036] In one embodiment of the present invention, it is particularly preferred that the temperature of the polyurethane prepolymer in step a) is 50°C to 70°C, the temperature of the mold in step b) is 30°C to 60°C, and the mixture of polyurethane prepolymer and curing agent is injected into the mold to a thickness of 2 mm to 3 mm in step b).

[0037] The polishing pad window of the present invention is manufactured by the manufacturing method of the present invention and has a transmittance of 5% or more, preferably 7% or more, and more preferably 8% or more, based on a thickness of 1.9 mm.

[0038] The present invention will be described in detail below with reference to examples. However, the examples according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the examples described below. The examples of the present invention are provided to more completely explain the present invention to those skilled in the art. [Example]

[0039] Example 1-1: Manufacturing a window for a polishing pad 80 wt% of a polyurethane prepolymer (PT411, product of KPX, NCO%: 9.2, viscosity: 24,000 cPs, weight average molecular weight: 1,850) heated to 90°C was mixed with 20 wt% of a curing agent (MOCA, 4,4'-methylenebis(2-chloroaniline)). The mixture was poured into a mold heated to 50°C and pre-cured for 1 hour, then post-cured in an oven for 16 hours to produce a 3 mm thick cake (cured polyurethane). The cake was then processed to a thickness of 1.9 mm to produce a window.

[0040] Example 1-2: Fabrication of a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Example 1-1, except that a polyurethane prepolymer having a temperature of 70° C. was used.

[0041] Examples 1-3: Fabrication of a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Example 1-1, except that a polyurethane prepolymer having a temperature of 50° C. was used in Example 1-1.

[0042] Example 2-1: Manufacturing a window for a polishing pad A 1.9 mm thick window was manufactured in the same manner as in Example 1-1, except that a polyurethane prepolymer heated to 70°C and a mold heated to 80°C were used.

[0043] Example 2-2: Fabrication of a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Example 2-1, except that a mold heated to 60°C was used.

[0044] Example 2-3: Fabrication of a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Example 2-1, except that a mold heated to 50° C. was used.

[0045] Examples 2-4: Fabrication of a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Example 2-1, except that a mold heated to 30° C. was used.

[0046] Example 3-1: Fabrication of a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Example 1-1, except that a polyurethane prepolymer heated to 70°C was used and the cake thickness was adjusted to 5 mm.

[0047] Example 3-2: Fabrication of a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Example 3-1, except that the thickness of the cake was adjusted to 4 mm.

[0048] Example 3-3: Fabrication of a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Example 3-1, except that the thickness of the cake was adjusted to 3 mm.

[0049] Examples 3-4: Fabrication of a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Example 3-1, except that the thickness of the cake was adjusted to 2 mm.

[0050] Comparative Example 1-1: Manufacturing a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Example 1-1, except that a polyurethane prepolymer heated to 100° C. was used.

[0051] Comparative Example 1-2: Manufacturing a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Example 1-1, except that a polyurethane prepolymer heated to 40° C. was used.

[0052] Comparative Example 2-1: Manufacturing a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Example 1-1, except that a polyurethane prepolymer heated to 70°C and a mold heated to 100°C were used.

[0053] Comparative Example 2-2: Manufacturing of a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Comparative Example 2-1, except that a mold heated to 20° C. was used.

[0054] Comparative Example 3-1: Manufacturing a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Example 1-1, except that a polyurethane prepolymer heated to 70°C was used and the cake thickness was adjusted to 6 mm.

[0055] Comparative Example 3-2: Manufacturing of a window for a polishing pad A window having a thickness of 1.9 mm was manufactured in the same manner as in Comparative Example 3-1, except that the thickness of the cake was adjusted to 8 mm.

[0056] Experimental example 1: Transmittance measurement The 1.9 mm thick windows manufactured in the examples and comparative examples were conditioned with a diamond disc (LPX2 product from Sasol) for 15 minutes, and then the transmittance was measured at 670 nm using a transmittance analyzer (UV-Visible Spectrometer Lambda-365 from Perkin Elmer). The results are shown in Table 1 below.

[0057] [Table 1]

[0058] In the case of Comparative Example 2-2, the transmittance increases depending on the mold temperature, but the polyurethane does not harden, making it difficult to apply to the manufacture of windows.

Claims

1. a) mixing a polyurethane prepolymer having a temperature of 50°C to 70°C with a curing agent to prepare a mixture; b) pouring the mixture into a mold heated to a temperature of 30°C to 60°C to a thickness of 2mm to 3mm; c) releasing the cured polyurethane from the mold; and d) processing the cured polyurethane into a thickness of a window of a polishing pad; The method for producing a window for a polishing pad is produced by polymerizing a composition containing one or more isocyanate compounds selected from the group consisting of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, naphthalene-1,5-diisocyanate, toluidine diisocyanate, paraphenylene diisocyanate, xylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and cyclohexane diisocyanate, and one or more polyol compound components selected from the group consisting of polyether polyol, polycarbonate polyol, polyester polyol, and polycaprolactone polyol.

2. 2. The method of claim 1, wherein the polyurethane prepolymer has a weight average molecular weight of 500 to 3,000.

3. 2. The method for manufacturing a window for a polishing pad according to claim 1, wherein the composition further comprises one or more chain extenders selected from the group consisting of ethylene glycol (EG), 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol (BDO), neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, and tripropylene glycol.

4. The curing agent may be 4,4'-methylenebis(2-chloroaniline) (MBOCA), diethyltoluenediamine (DETDA), 3,5-dimethylthio-2,4-toluenediamine and its isomers; 3,5-diethyltoluene-2,4-diamine and its isomers; 4,4'-bis-(sec-butylamino)-diphenylmethane; 1,4-bis(sec-butylamino)-benzene; 4,4'-methylenebis(2-chloroaniline); 4,4'-methylenebis(3-chloro-2,6-diethylaniline) (MCDEA); polytramethyleneoxide-di-p-aminobenzoate; N,N'- 2. The method for producing a window for a polishing pad according to claim 1, characterized in that the additive is one or more selected from the group consisting of dialkyldiaminodiphenylmethane; p,p'-methylenedianiline (MDA); m-phenylenediamine (MPDA); 4,4'-methylenebis(2,6-diethylaniline) (MDEA); 4,4'-methylenebis(2,3-dichloroaniline) (MDCA); 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane; 2,2',3,3'-tetrachlorodiaminodiphenylmethane; and trimethylene glycol di-p-aminobenzoate.

5. 2. The method of claim 1, wherein the polyurethane prepolymer and the curing agent are mixed in a weight ratio of 9:1 to 7:3 on a dry weight basis.

6. 2. The method of claim 1, wherein the window has a transmittance of 5% or more for 670 nm light based on a thickness of 1.9 mm.

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