Polishing pad with improved transmittance, manufacturing method therefor, and window block used therein

Abstract

A polishing pad according to one implementation comprises a top pad having at least one window block, wherein the window block includes a polyurethane resin, the polyurethane resin includes an isocyanate component and a polyol component, and the polyol component includes 60 mol% or more of a compound of formula (1). The polishing pad according to the implementation can increase the accuracy of thickness measurement by improving transmittance of the window block and can improve the efficiency and reliability of CMP by providing excellent hardness of the window block.

Description

Abrasive pad with improved transmittance, method of manufacturing the same, and window block used therein

[0001] An embodiment relates to a polishing pad used in a chemical mechanical polishing (CMP) process of a semiconductor device, a method for manufacturing the same, and a window block used therein.

[0002]

[0003] The importance of the Chemical Mechanical Polishing (CMP) process is continuously increasing due to the rise in semiconductor chip integration density and the miniaturization of semiconductor circuits. Precision is critical for enhancing the performance and efficiency of semiconductor chips, and the CMP process plays a decisive role among them. Polishing pads, a key auxiliary material for performing the CMP process, play a core role, and maintaining the thickness and uniformity of the top pad is essential to ensure the precision of the semiconductor chip circuits.

[0004] The technology for measuring the thickness of the top pad during the CMP process plays a crucial role in enhancing process precision, thereby significantly improving process efficiency and stability. Among these methods, interferometric measurement, which calculates film thickness using the interference spectrum of light reflected from the wafer surface, is a widely used technique. To this end, a window is formed on the top pad to allow light transmission, enabling the measurement of light reflected from the wafer surface.

[0005] Korean Patent Registration No. 1120647 discloses a polishing pad having a window formed inside by reacting an aliphatic polyisocyanate, a hydroxyl-containing material, and a curing agent. The window block generally uses a non-foamed polyurethane material and can maintain a basically transparent state because it has no pores inside. However, transmittance decreases due to fine scratches generated during the surface processing, which becomes a major problem that makes it difficult to use in the CMP process.

[0006] Various approaches are being researched to enhance the transparency of polishing pad windows. For example, transmittance can be improved by minimizing scratches through the optimization of surface processing and by controlling the structure of polymer chains through the adjustment of raw material selection and synthesis conditions. These technical approaches improve the performance of polishing pads used in the CMP process and contribute to increasing the precision and reliability of the semiconductor chip manufacturing process.

[0007] [Prior Art Literature]

[0008] [Patent Literature]

[0009] (Patent Document 1) Korean Patent Registration No. 1120647 (Feb. 20, 2012)

[0010]

[0011] The inventors were able to realize a polishing pad that can further improve the efficiency and reliability of the CMP process by controlling the structure of the polymer chain to improve the transmittance of the window block and maintain high transparency even with repetitive process use.

[0012] Accordingly, the objective of the present invention is to provide a polishing pad that improves the transmittance of a window block to increase the accuracy of thickness measurement during a CMP process, a method for manufacturing the same, and a window block used therein.

[0013]

[0014] According to one embodiment, a polishing pad is provided, comprising a top pad having one or more window blocks, wherein the window blocks comprise a polyurethane resin, the polyurethane resin comprises an isocyanate component and a polyol component, and the polyol component comprises 60 mol% or more of a compound of Formula (1) below:

[0015] (1)

[0016] Here, R is an alkyl group having 1 to 6 carbon atoms, and n is an integer from 500 to 3000.

[0017] According to another embodiment, a window block for a polishing pad is provided, comprising a polyurethane resin, wherein the polyurethane resin comprises an isocyanate component and a polyol component, wherein the polyol component comprises 60 mol% or more of the compound of formula (1) and has a transmittance of 30% or more.

[0018] According to another embodiment, a method for manufacturing a polishing pad is provided, comprising the steps of: manufacturing a window block using an isocyanate component, a polyol component, and a curing agent; and combining the window block with a top pad and surface processing, wherein the polyol component comprises 60 mol% or more of the compound of Formula (1).

[0019]

[0020] According to the above embodiment, by controlling the structure of the polymer chains constituting the window block in the polishing pad to improve transmittance, high transparency can be maintained even during repetitive CMP processes. A polishing pad having a window block with such improved transmittance exhibits excellent accuracy in thickness measurement. Furthermore, the polishing pad according to the above embodiment has excellent hardness of the window block, which can further enhance the efficiency and reliability of the CMP process.

[0021]

[0022] Figure 1 shows the transmittance spectrum according to the composition of the window block for the polishing pad in Test Example 1.

[0023] Figure 2 shows the transmittance spectrum according to the thickness of the window block for the polishing pad in Test Example 2.

[0024]

[0025] In describing the embodiments below, detailed descriptions of related known configurations or functions are omitted if it is determined that such descriptions could obscure the essence of the embodiments. Additionally, the sizes of each component in the drawings may be exaggerated or omitted for illustrative purposes and may differ from the actual sizes applied.

[0026] In this specification, the description that one component is formed above or below another component, or is connected or coupled to one another, includes both direct formation, connection, or coupling between these components and indirect formation, connection, or coupling through the interposition of another component. Furthermore, it should be understood that the criteria for the "above" and "below" of each component may vary depending on the direction in which the object is observed.

[0027] In this specification, terms referring to each component are used to distinguish them from other components and are not intended to limit the embodiments. Additionally, in this specification, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0028] In this specification, terms such as "first," "second," etc. are used to describe various components, and said components should not be limited by said terms. These terms are used for the purpose of distinguishing one component from another.

[0029] In this specification, the use of the term "comprising" is intended to specify characteristics, regions, steps, processes, elements, and components, and unless specifically stated otherwise, it does not exclude the existence or addition of other characteristics, regions, steps, processes, elements, or components.

[0030] For convenience, the molecular weights of compounds or polymers described in this specification are indicated in units of molar mass, but they may be understood as relative masses based on carbon-12. Furthermore, the molecular weights of polymers described in this specification may be interpreted as number-average molecular weight or weight-average molecular weight, for example, as number-average molecular weight.

[0031] In numerical ranges defining the size, physical properties, etc., of components described in this specification, if a numerical range in which only the upper limit is defined and a numerical range in which only the lower limit is defined are separately exemplified, it should be understood that a numerical range combining these upper and lower limits is also included in the exemplary range.

[0032]

[0033] Window block for polishing pad

[0034] A polishing pad according to one embodiment includes a top pad having one or more window blocks.

[0035] The above window block comprises a polyurethane resin. The above polyurethane resin comprises an isocyanate component and a polyol component.

[0036] In one embodiment, the polyol component of the polyurethane resin included in the window block comprises a compound of the following formula (1).

[0037] (1)

[0038] Here, R is an alkyl group having 1 to 6 carbon atoms, and n is an integer from 500 to 3000.

[0039] In the above formula (1), R may be methyl, ethyl, propyl, butyl, pentyl, or hexyl. For example, in the above formula (1), R may be methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, n-pentyl, i-pentyl, t-pentyl, sec-pentyl, neo-pentyl, or hexyl.

[0040] Specifically, in the above formula (1), R can be, for example, an alkyl having 1 to 3 carbon atoms, and more specifically, R can be methyl or ethyl.

[0041] In the above formula (1), n ​​can be, for example, an integer from 500 to 2500, and specifically, an integer from 500 to 2000, an integer from 500 to 1500, an integer from 500 to 1000, an integer from 800 to 1200, an integer from 1000 to 2500, an integer from 1000 to 2000, an integer from 1000 to 1500, an integer from 1500 to 2500, an integer from 1500 to 2000, or an integer from 2000 to 2500.

[0042] In one embodiment, in the above formula (1), R is methyl or ethyl and n can be 800 to 1200.

[0043] In one embodiment, the content of the compound of formula (1) among the polyol components of the polyurethane resin included in the window block is 60 mol% or more (based on 100 mol% of the total polyol components).

[0044] For example, among the polyol components of the polyurethane resin included in the window block, the content of the compound of Formula (1) may be 70 mol% or more, or 80 mol% or more. In one embodiment, the polyol component may contain 90 mol% or more of the compound of Formula (1).

[0045] Specifically, among the polyol components of the polyurethane resin included in the window block, the content of the compound of formula (1) may be 60 mol% to 100 mol%, 70 mol% to 100 mol%, 80 mol% to 100 mol%, or 90 mol% to 100 mol%.

[0046] Meanwhile, the above polyol component may not contain the compound of formula (2) below, or may contain 10 mol% or less.

[0047] (2)

[0048] Here, p is an integer from 1 to 3, and m is an integer from 500 to 3000.

[0049] For example, in the above equation (2), p can be 1 or 2, and specifically, it can be 1.

[0050] In addition, in the above formula (2), m can be, for example, an integer from 500 to 2500, and specifically, an integer from 500 to 2000, an integer from 500 to 1500, an integer from 500 to 1000, an integer from 1000 to 2500, an integer from 1000 to 2000, an integer from 1000 to 1500, an integer from 1500 to 2500, an integer from 1500 to 2000, or an integer from 2000 to 2500.

[0051] According to one embodiment, in the above formula (1), R is methyl or ethyl and n is 800 to 1200, and the polyol component may contain 90 mol% or more of the compound of the above formula (1) and may not contain or may contain 10 mol% or less of the compound of the above formula (2).

[0052] According to the above embodiment, by controlling the structure of the polymer chains constituting the window block in the polishing pad to improve transmittance, high transparency can be maintained even during repeated CMP processes. A polishing pad having a window block with such improved transmittance exhibits excellent accuracy in thickness measurement, thereby further enhancing the efficiency and reliability of the CMP process.

[0053] In polishing pads, the window block is composed of polyurethane material; due to the nature of polymer materials, transparency can be enhanced as the chain structure of the raw materials becomes amorphous. The amorphous characteristics of the polymer structure play a crucial role in increasing light transmittance, resulting in a higher transmittance for the window block. This improvement in transmittance minimizes the problem of transmittance degradation during polishing pad use and enables the acquisition of highly reliable measurement results without shortening the pad's usage time. Therefore, using a window block with high transmittance is a critical factor in enhancing efficiency and reliability in semiconductor manufacturing processes. In particular, accurate measurement of the remaining thickness during polishing pad use is vital for process quality control, and a window block with high transmittance facilitates this quality control process.

[0054] The polyurethane material constituting the window block above may include a urethane-based prepolymer and a curing agent. The urethane-based prepolymer may include an isocyanate compound and a polyol, and may include unreacted isocyanate groups (NCO). The curing agent may be one or more of amine compounds and alcohol compounds, and specifically may include one or more compounds selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols.

[0055] As such, the above window block is non-foamed because it contains a urethane-based prepolymer and a curing agent but does not contain a foaming agent, and since no microbubbles exist within the window, the possibility of the polishing liquid penetrating into the polishing pad is reduced, thereby improving the precision of optical endpoint detection and preventing damage to the light transmission area.

[0056] The number of window blocks provided on the polishing pad may be one or more, for example, 1 to 6, 1 to 5, 1 to 4, or 1 to 3.

[0057] The thickness of the window block may be, for example, 0.5 mm or more, 0.8 mm or more, 1.0 mm or more, 1.2 mm or more, 1.4 mm or more, or 1.5 mm or more, and may also be 3.0 mm or less, 2.5 mm or less, 2.0 mm or less, 1.8 mm or less, 1.6 mm or less, or 1.4 mm or less. Specifically, the thickness of the window block may be 0.5 mm to 3.0 mm, 0.8 mm to 2.5 mm, 1.0 mm to 2.0 mm, 1.2 mm to 1.6 mm, 1.0 mm to 1.4 mm, or 1.4 mm to 2.0 mm.

[0058] The shape of the above window block is not particularly limited, but, for example, it may be cylindrical or have the shape of a rectangular prism.

[0059] The diameter of the planar shape of the window block above may be, for example, 5 mm to 50 mm, more specifically 10 mm to 30 mm.

[0060] The surface roughness of the window block above can be adjusted within a certain range for transparency. For example, the Ra roughness of the window block above may be 0.4 μm or more, 0.5 μm or more, or 0.6 μm or more, and may also be 2.0 μm or less, 1.0 μm or less, 0.8 μm or less, or 0.7 μm or less. In one embodiment, the Ra roughness of the window block above may be 0.4 μm to 0.7 μm.

[0061] The hardness of the window block above may be, for example, 30 Shore D or more, 40 Shore D or more, or 50 Shore D or more, and may also be 90 Shore D or less, 80 Shore D or less, 70 Shore D or less, or 60 Shore D or less. Specifically, it may be 30 Shore D to 90 Shore D, 40 Shore D to 90 Shore D, 30 Shore D to 80 Shore D, 40 Shore D to 80 Shore D, 30 Shore D to 70 Shore D, 40 Shore D to 70 Shore D, 50 Shore D to 90 Shore D, 50 Shore D to 80 Shore D, or 50 Shore D to 70 Shore D.

[0062] In one embodiment, the transmittance of the window block for light of a wavelength of 440 nm is 30% or more.

[0063] For example, the transmittance of the window block for light of a wavelength of 440 nm may be 40% or more, 50% or more, or 60% or more.

[0064] In one embodiment, the transmittance of the window block for light of a wavelength of 440 nm may be 70% or more.

[0065] Specifically, the transmittance of the window block for light with a wavelength of 440 nm may be 75% or more.

[0066] In another embodiment, the transmittance of the window block for light of a wavelength of 440 nm may be 30% to 90%, 40% to 90%, 50% to 90%, 60% to 90%, 70% to 90%, or 75% to 90%.

[0067] As the light transmittance is within the above range, the polishing endpoint of the wafer can be detected more accurately.

[0068] The transmittance of the above window block at a wavelength of 440 nm can be measured, for example, using a UV-Vis spectrophotometer.

[0069] In addition, the refractive index of the window block may be, for example, 1.40 to 1.65, 1.45 to 1.60, or 1.48 to 1.58. As the refractive index is within the above range, the polishing endpoint of the wafer can be detected more accurately.

[0070] In one embodiment, the window block has a thickness of 1.0 mm to 2.0 mm and may have a transmittance of 30% or more for light of a wavelength of 440 nm.

[0071] In another embodiment, the window block may have an Ra roughness of 0.4 μm to 0.7 μm and a hardness of 40 Shore D to 80 Shore D.

[0072] In one embodiment, the window block for the polishing pad may have a transmittance of 70% or more for light of a wavelength of 440 nm and a hardness of 40 Shore D to 80 Shore D.

[0073] A polishing pad having a window block with improved transmittance as described above offers excellent accuracy in thickness measurement. Furthermore, the polishing pad according to the above embodiment has excellent hardness of the window block, which can further improve the efficiency and reliability of the CMP process.

[0074] The wear rate of the above window may be equal to or slightly higher than the wear rate of the polishing layer. In this case, after polishing for a certain period of time, the problem of only the window portion protruding and causing scratches on the polished wafer can be prevented.

[0075] In one embodiment, the lower surface of the window block may coincide with the lower surface of the top pad. In another embodiment, the lower surface of the window block may be lower than the lower surface of the top pad. Specifically, the height difference between the lower surface of the window block and the lower surface of the top pad may be 0.1 mm to 1.0 mm, and specifically 0.1 mm to 0.6 mm, 0.2 mm to 0.6 mm, or 0.2 mm to 0.4 mm.

[0076]

[0077] Top pad

[0078] The above top pad serves to polish a wafer to be polished. Such a top pad can be manufactured using a composition for forming a top pad that includes a urethane-based prepolymer, a curing agent, and a foaming agent.

[0079] The urethane-based prepolymer included in the composition for forming the top pad may be a polymer obtained through the reaction of a polyol compound and an isocyanate compound. Such a urethane-based prepolymer may have a weight-average molecular weight (Mw) of 500 to 3,000, specifically 600 to 2,000, 700 to 1,500, or 800 to 1,000. In addition, the isocyanate group content (the percentage of the weight of isocyanate groups (-NCO) existing as free reactants without undergoing a urethane reaction, NCO%) of the urethane-based prepolymer may be 6% to 10% by weight, specifically 7% to 9% by weight, or 7.5% to 8.5% by weight. As the weight-average molecular weight and isocyanate group content of the urethane-based prepolymer are within the above ranges, a top pad with high mechanical properties can be formed.

[0080] The polyol compound for obtaining the above urethane-based prepolymer may specifically be one or more selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, and acrylic polyol. More specifically, the polyol compound may include one or more selected from the group consisting of polytetramethylene ether glycol, polypropylene ether glycol, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, and tripropylene glycol.

[0081] The above polyol compound may include a low molecular weight polyol with a weight-average molecular weight (Mw) of 100 to 300 and a high molecular weight polyol with a weight-average molecular weight (Mw) of 300 to 1800. Since the above polyol compound is a mixture of the low molecular weight polyol and the high molecular weight polyol, a top pad having high mechanical properties and an appropriate pore size can be formed.

[0082] The isocyanate compound for obtaining the above urethane-based prepolymer may specifically be one or more selected from the group consisting of aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates. More specifically, the isocyanate compound may include one or more selected from the group consisting of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, naphthalene-1,5-diisocyanate, para-phenylene diisocyanate (p-phenylene diisocyanate), tolidine diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate.

[0083] The curing agent included in the above composition for forming the top pad may include a compound that undergoes a curing reaction with the above urethane-based prepolymer. Specifically, the curing agent may include one or more selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols. More specifically, the curing agent may include one or more selected from the group consisting of 4,4'-methylenebis(2-chloroaniline), diethyltoluenediamine, diaminodiphenylmethane, dimethylthiotoluenediamine, 1,3-propanediol bis(4-aminobenzoate), diaminodiphenylsulfone, m-xylylenediamine, isophoronediamine, ethylenediamine, diethylenetriamine, triethylenetetraamine, polypropylenediamine, polypropylenetriamine, and bis(4-amino-3-chlorophenyl)methane.

[0084] The content of such curing agent may be 18 to 28 parts by weight per 100 parts by weight of the urethane-based prepolymer, specifically 19 to 27 parts by weight, or 20 to 26 parts by weight.

[0085] The foaming agent included in the composition for forming the top pad may specifically include one or more selected from the group consisting of solid foaming agents, gaseous foaming agents, and liquid foaming agents. More specifically, the foaming agent may be a solid foaming agent, a gaseous foaming agent, or a mixture thereof.

[0086] The above-mentioned solid foaming agent may be a foaming agent containing expandable particles. The expandable particles are particles having the characteristic of being able to expand by heat or pressure, etc., and their final size may be determined by the heat or pressure, etc. applied during the process of forming the top pad. Specifically, the expandable particles may be thermally expanded particles, unexpanded particles, or a mixture thereof. The thermally expanded particles refer to particles that have been pre-expanded by heat, meaning particles that undergo little or almost no change in size due to the heat or pressure applied during the process of forming the top pad. The unexpanded particles refer to particles that have not been pre-expanded, meaning particles that expand by the heat or pressure applied during the process of forming the top pad, thereby determining their final size.

[0087] The content of such solid foaming agent may be 0.5 to 10 parts by weight per 100 parts by weight of the urethane-based prepolymer, and specifically, may be 1 to 5 parts by weight, 1.3 to 3 parts by weight, or 1.3 to 2.6 parts by weight.

[0088] The above gaseous blowing agent may be a blowing agent comprising a commonly known inert gas (e.g., nitrogen gas (N2), argon gas (Ar), helium gas (He), etc.). Such a gaseous blowing agent may be injected through a predetermined injection line during the process of mixing the urethane-based prepolymer, the curing agent, and / or the solid blowing agent. The injection rate of the gaseous blowing agent may be 0.8 to 2.0 L / min, 0.7 to 1.8 L / min, or 1.0 to 1.7 L / min.

[0089] The above composition for forming a top pad may further include one or more additives selected from the group consisting of surfactants (e.g., silicone-based surfactants), pH adjusters, antioxidants, reaction rate regulators, heat stabilizers, and dispersion stabilizers.

[0090] The top pad has one or more through holes into which the window block is inserted. The diameter of the through hole may be the same as the diameter of the window block. Additionally, the depth of the through hole may be the same as the thickness of the top pad.

[0091] After the window block is inserted into the through hole, the upper surface of the window block may coincide with the upper surface of the top pad. Alternatively, after the window block is inserted into the through hole, the upper surface of the window block may be lower than the upper surface of the top pad. Specifically, the height difference between the upper surface of the window block and the upper surface of the top pad may be 0.1 mm to 1.0 mm, and specifically, 0.1 mm to 0.6 mm, 0.2 mm to 0.6 mm, or 0.2 mm to 0.4 mm.

[0092] The top pad may have grooves on its surface for mechanical polishing. The grooves may have an appropriate depth, width, and spacing for mechanical polishing and are not particularly limited.

[0093] The thickness of the top pad may be, for example, 0.8 mm or more, 1.0 mm or more, 1.2 mm or more, 1.5 mm or more, 1.8 mm or more, or 2.0 mm or more, and may also be 4.0 mm or less, 3.5 mm or less, 3.0 mm or less, 2.5 mm or less, or 2.0 mm or less, and specifically may be 0.8 mm to 4.0 mm, 1.0 mm to 3.5 mm, 1.0 mm to 3.0 mm, 1.5 mm to 3.0 mm, or 1.5 mm to 2.5 mm. In this specification, the thickness of the top pad may refer to the average thickness of the top pad.

[0094]

[0095] Other components

[0096] The polishing pad further includes a bottom pad bonded to the lower surface of the top pad, and the bottom pad may have through holes corresponding to each through hole of the top pad.

[0097] The bottom pad supports the top pad and absorbs and disperses external shocks applied to the top pad, thereby minimizing damage and defects to the object to be polished during the polishing process in which the polishing pad is applied.

[0098] The above lower pad may include non-woven fabric or suede, but is not limited thereto.

[0099] In one embodiment, the lower pad may be a resin-impregnated nonwoven fabric. The nonwoven fabric may be a fiber nonwoven fabric comprising one selected from the group consisting of polyester fibers, polyamide fibers, polypropylene fibers, polyethylene fibers, and combinations thereof.

[0100] The resin impregnated in the above nonwoven fabric may include one selected from the group consisting of polyurethane resin, polybutadiene resin, styrene-butadiene copolymer resin, styrene-butadiene-styrene copolymer resin, acrylonitrile-butadiene copolymer resin, styrene-ethylene-butadiene-styrene copolymer resin, silicone rubber resin, polyester-based elastomer resin, polyamide-based elastomer resin, and combinations thereof.

[0101] The thickness of the lower pad may, for example, be 0.3 mm or more or 0.5 mm or more, and may also be 3 mm or less, 2 mm or less, or 1 mm or less. As a specific example, the thickness of the lower pad may be 0.3 mm to 3 mm, or 0.5 mm to 1 mm.

[0102] The hardness of the lower pad may, for example, be 50 Asker C or higher, 60 Asker C or higher, or 70 Asker C or higher, and may also be 100 Asker C or lower, 90 Asker C or lower, or 80 Asker C or lower. As a specific example, the hardness of the lower pad may be 50 Asker C to 100 Asker C, or 60 Asker C to 90 Asker C.

[0103] In one embodiment, the diameter of the through hole of the top pad may be 1.1 to 2.0 times the diameter of the through hole of the lower pad. For example, the diameter of the through hole of the top pad may be 1.1 times or more, 1.2 times or more, 1.3 times or more, 1.4 times or more, 1.5 times or more, or 1.6 times or more than the diameter of the through hole of the lower pad, and may also be 2.0 times or less, 1.9 times or less, 1.8 times or less, or 1.7 times or less, and specifically, may be 1.1 to 2.0 times, 1.3 to 2.0 times, 1.5 to 2.0 times, 1.1 to 1.8 times, 1.3 to 1.8 times, or 1.5 to 1.8 times. Within the above diameter ratio range, it may be advantageous to improve airtightness between the top pad and the window to suppress leakage of slurry during polishing processes such as CMP.

[0104] In addition, an adhesive layer may be inserted between the top pad and the bottom pad.

[0105] The adhesive layer may include a hot melt adhesive. The hot melt adhesive may be one or more selected from the group consisting of polyurethane resin, polyester resin, ethylene-vinyl acetate resin, polyamide resin, and polyolefin resin. Specifically, the hot melt adhesive may be one or more selected from the group consisting of polyurethane resin and polyester resin.

[0106] In addition, double-sided tape may be laminated to the lower part of the lower pad, and when applied to CMP equipment, the release liner of the double-sided tape may be removed and attached to the platen for use.

[0107] Additionally, an adhesive may be added to the area where the window block and the top pad and / or bottom pad come into contact. In one embodiment, an adhesive may be added to the surface of the bottom pad exposed to the through hole of the top pad. In another embodiment, an adhesive may be added to the lower inner wall of the through hole. In yet another embodiment, an adhesive may be added to the lower inner wall of the through hole and to the surface of the bottom pad exposed to the through hole of the top pad. Such an adhesive may be advantageous for improving airtightness between the top pad and the window, thereby suppressing leakage of slurry during polishing processes such as CMP.

[0108]

[0109] Method for manufacturing a polishing pad

[0110] A method for manufacturing a polishing pad according to one embodiment comprises: (a) a step of manufacturing a window block using an isocyanate component, a polyol component, and a curing agent; and (b) a step of combining the window block with a top pad and surface processing, wherein the polyol component comprises 60 mol% or more of the compound of formula (1).

[0111] Each step is explained in detail below.

[0112] In step (a) above, a window block is manufactured using an isocyanate component, a polyol component, and a curing agent.

[0113] In one embodiment, the step of manufacturing the window block may include: (a1) a step of manufacturing a urethane prepolymer by polymerizing an isocyanate component and a polyol component; and (a2) a step of manufacturing a window block by mixing the urethane prepolymer with a curing agent and molding it.

[0114] The above window block can be manufactured using a composition comprising a urethane-based prepolymer and a curing agent. The urethane-based prepolymer may be prepared by reacting an isocyanate compound with a polyol and may contain unreacted isocyanate groups (NCO). The curing agent may be one or more of amine compounds and alcohol compounds, and specifically may include one or more compounds selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols. A window sheet can be manufactured by injecting the composition comprising the prepolymer and curing agent into a mold at, for example, 80°C to 100°C and curing it for 10 to 60 minutes, and then curing it in an oven at 80°C to 120°C for 12 to 48 hours. Alternatively, a window sheet with a low surface roughness can be manufactured by casting the composition comprising the prepolymer and curing agent onto a glass plate with a clean and transparent surface. Subsequently, a window block can be obtained by cutting the window sheet to adjust the thickness and using equipment such as a tip to adjust the surface roughness to a low level.

[0115] As such, the window block can be manufactured using a composition that includes a urethane-based prepolymer and a curing agent, but does not include a foaming agent. In one embodiment, the window block can be manufactured by performing the same method as the top pad manufacturing method described above, but without using a foaming agent. As a result, the manufactured window block is non-foamed and, since no micro-bubbles exist within the window, the possibility of the polishing liquid penetrating into the polishing pad is reduced, thereby improving the precision of optical endpoint detection and preventing damage to the light transmission area.

[0116] In step (b) above, the window block is joined with the top pad and surface processed. Additionally, the top pad may be joined with the bottom pad and may undergo surface processing.

[0117] In one embodiment, the manufacturing step of the window block may include: (b1) providing a top pad having one or more through holes; (b2) joining the top pad to a lower pad; (b3) inserting the window block into the through holes of the top pad; and (b4) processing the surfaces of the top pad and the window block.

[0118] The top pad may comprise a urethane-based polymer prepared from a composition comprising a urethane-based prepolymer, a curing agent, a foaming agent, and other additives. The prepolymer generally refers to a polymer having a relatively low molecular weight in which the degree of polymerization is stopped at an intermediate stage to facilitate molding of the final product. The prepolymer may be molded as is or after reacting with other polymerizable compounds. Specifically, the urethane-based prepolymer is prepared by reacting an isocyanate compound with a polyol and may contain unreacted isocyanate groups (NCO). The isocyanate compound and the polyol compound are not particularly limited as long as they are usable for the manufacture of the urethane-based polymer. The curing agent may be one or more of amine compounds and alcohol compounds. Specifically, the curing agent may comprise one or more compounds selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols. The foaming agent is not particularly limited as long as it is commonly used for forming pores in the polishing pad. For example, the blowing agent may be one or more selected from a solid blowing agent having a hollow structure, a liquid blowing agent using a volatile liquid, and an inert gas.

[0119] The formation of the through hole in the top pad can be performed by using a perforator to punch a hole at the location where the window block is to be inserted in the top pad.

[0120] Subsequently, the top pad is joined to the bottom pad. The joining can be performed after applying an adhesive or adhesive tape to the lower surface of the top pad and the upper surface of the bottom pad, respectively. The adhesive or adhesive tape may be applied to the portion of the lower surface of the top pad and the upper surface of the bottom pad that does not have a through hole.

[0121] In addition, a through hole may be formed in the lower pad at a position corresponding to the through hole of the top pad.

[0122] A window block is inserted into the through hole of the top pad.

[0123] After the window block is inserted into the through hole, the lower surface of the window block may align with the lower surface of the top pad. Alternatively, after the window block is inserted into the through hole, the lower surface of the window block may be lower than the lower surface of the top pad.

[0124] In addition, after the window block is inserted into the through hole, the upper surface of the window block may align with the upper surface of the top pad. Alternatively, after the window block is inserted into the through hole, the upper surface of the window block may be lower than the upper surface of the top pad.

[0125] Since the transmittance of the above window block decreases as the surface roughness value increases during processing such as cutting, surface processing can be performed to control the surface roughness of the window block. For example, the surface roughness can be controlled to a range of 0.5 μm to 1.0 μm based on the Ra value using equipment such as a tip.

[0126] Before insertion, adhesive may be applied in advance to the area where the window block contacts the top pad and / or bottom pad.

[0127] In one embodiment, an adhesive may be applied to the surface of the lower pad exposed to the through hole of the top pad prior to the insertion of the window block. In another embodiment, an adhesive may be applied to the lower inner wall of the through hole prior to the insertion of the window block. In yet another embodiment, an adhesive may be applied to the lower inner wall of the through hole and to the surface of the lower pad exposed to the through hole of the top pad prior to the insertion of the window block. Such application of the adhesive may be advantageous in suppressing leakage of slurry during polishing processes such as CMP by improving airtightness between the top pad and the window.

[0128] A groove may be formed on the surface of the top pad. The formation of the groove may be performed by cutting and removing a portion of the surface of the top pad. For example, the surface of the top pad may be cut by a tip to form a groove.

[0129]

[0130] Method for manufacturing a semiconductor device

[0131] A semiconductor device can be manufactured through chemical mechanical polishing using the polishing pad described above. A method for manufacturing a semiconductor device according to one embodiment includes the step of performing chemical mechanical polishing (CMP) on the surface of a semiconductor substrate using the polishing pad described above.

[0132] Specifically, the method for manufacturing the semiconductor device may include the step of providing a polishing pad according to the above embodiment; and the step of polishing the surface of the semiconductor substrate by rotating relative to each other so that the surface of the top pad of the polishing pad and the surface of the semiconductor substrate come into contact with each other.

[0133] First, after mounting the polishing pad according to the above embodiment on a platen, a semiconductor substrate to be polished is placed on the polishing pad. At this time, the surface of the semiconductor substrate is in direct contact with the top pad of the polishing pad. For polishing, a polishing slurry may be sprayed onto the polishing pad through a nozzle. The flow rate of the polishing slurry supplied through the nozzle is approximately 10 cm 3 / min to about 1,000 cm 3 It can be selected according to the purpose within the / minute range, for example, about 50 cm 3 / min to about 500 cm 3 / It may be in minutes, but is not limited to this.

[0134] Subsequently, the semiconductor substrate and the polishing pad may rotate relative to each other so that the surface of the semiconductor substrate can be polished. At this time, the rotation direction of the semiconductor substrate and the rotation direction of the polishing pad may be the same direction or opposite directions. The rotation speeds of the semiconductor substrate and the polishing pad may be selected according to the purpose within a range of about 10 rpm to about 500 rpm, for example, about 30 rpm to about 200 rpm, but are not limited thereto.

[0135] The semiconductor substrate can be mounted on the polishing head and pressed against the top pad of the polishing pad with a predetermined load, after which its surface can be polished. The load applied to the surface of the semiconductor substrate and the surface of the polishing pad by the polishing head is approximately 1 gf / cm² 2 Up to about 1,000 gf / cm 2 It can be selected from the range depending on the purpose, for example, about 10 gf / cm² 2 Up to about 800 gf / cm 2 It may be, but is not limited to this.

[0136] In one embodiment, the semiconductor substrate to be polished may include an oxide film, a tungsten film, or a composite film thereof. Specifically, the semiconductor substrate may include an oxide film, a tungsten film, or a composite film of an oxide film and a tungsten film. The composite film of the oxide film and the tungsten film may be a multilayer film in which the tungsten film is laminated on one surface of the oxide film, or a single layer film in which an oxide region and a tungsten region are mixed within a single layer.

[0137] In one embodiment, the method for manufacturing the semiconductor device may further include, in the step of polishing the target to be polished, a step of supplying either the oxide film polishing slurry and the tungsten film polishing slurry; or a step of sequentially supplying the oxide film polishing slurry and the tungsten film polishing slurry to the surface of a top pad.

[0138] For example, if the semiconductor substrate to be polished includes an oxide film, the method for manufacturing the semiconductor device may include a step of supplying a slurry for polishing the oxide film. If the semiconductor substrate includes a tungsten film, the method for manufacturing the semiconductor device may include a step of supplying a slurry for polishing the tungsten film. If the semiconductor substrate includes a composite film of an oxide film and a tungsten film, the method for manufacturing the semiconductor device may include a step of sequentially supplying the oxide film polishing slurry and the tungsten film polishing slurry to the surface of a top pad. At this time, depending on the process, the oxide film polishing slurry may be supplied first and then the tungsten film polishing slurry may be supplied later, or the tungsten film polishing slurry may be supplied first and then the oxide film polishing slurry may be supplied later.

[0139] In one embodiment, the method for manufacturing the semiconductor device may further include the step of processing the surface of the top pad of the polishing pad through a conditioner simultaneously with polishing the semiconductor substrate in order to maintain the surface of the top pad of the polishing pad in a state suitable for polishing.

[0140]

[0141] The following embodiments are described, but the scope of implementation is not limited to these.

[0142]

[0143] <Manufacturing and Evaluation of Window Blocks for Grinding Pads>

[0144]

[0145] Example 1: Manufacture of a window block (W-1) for a polishing pad

[0146] 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), dicyclohexylmethane diisocyanate (H12MDI), polypropylene glycol (PPG), and diethylene glycol (DEG) were added to a 4-necked flask and reacted at 80°C for 3 hours to prepare a urethane-based prepolymer having a terminal NCO group content (NCO%) of 10 wt%.

[0147] Among the monomers of the above urethane-based prepolymer, polypropylene glycol (PPG) having a branched structure as shown in the following formula (1a) and a number average molecular weight (Mn) of about 1000 was used as the polyol.

[0148] (1a)

[0149] A casting device equipped with a tank and an input line for supplying each raw material was prepared, and 32 parts by weight of a curing agent (4,4'-methylenebis(2-chloroaniline); MOCA) and 1 part by weight of a silicone-based surfactant were filled into each tank relative to 100 parts by weight of the previously manufactured urethane-based prepolymer.

[0150] The raw materials were fed into the mixing head at a constant speed through each input line while being stirred. The rotation speed of the mixing head was set to approximately 5,000 rpm. After the mixture of the raw materials was mixed in the mixing head, it was injected into a mold measuring 1,000 mm in width, 1,000 mm in length, and 3 mm in height. The temperature of the mold was controlled to approximately 80 (±5)°C. The mixture solidified and cured within the mold to form a sheet. The sheet was then subjected to a cutting process and surface processing using a tip to obtain a window block with an average thickness of 2 mm.

[0151]

[0152] Example 2: Manufacture of a window block (W-2) for a polishing pad

[0153] The same procedure as in Example 1 above was repeated, but polypropylene glycol (PPG) having a branched structure as shown in Formula (1a) and a number average molecular weight (Mn) of about 2000 was used as the polyol among the monomers of the urethane-based prepolymer to produce a window block with an average thickness of 2 mm.

[0154]

[0155] Comparative Example 1: Manufacture of a window block (Ref) for a polishing pad

[0156] The same procedure as in Example 1 above was repeated, but polytetramethylene ether glycol (PTMEG) and polypropylene glycol (PPG) were used as polyols in a weight ratio of 1:1 among the monomers of the urethane-based prepolymer to produce a window block with an average thickness of 2 mm.

[0157]

[0158] Test Example 1: Evaluation of Window Block for Grinding Pad (Before Surface Processing)

[0159] The window blocks for polishing pads manufactured in the above examples and comparative examples were tested as follows.

[0160] (1) Illumination (Ra)

[0161] The surface roughness (Ra) of the window block was measured using a non-contact 3D Optical Profiler (Contour GT, Bruker).

[0162] (2) Hardness (Shore D)

[0163] A sample was prepared by cutting a window block to a size of 2 cm x 2 cm (thickness: 2 mm), and then left to stand for 16 hours in an environment with a temperature of 25℃ and a relative humidity of 50±5%. Afterward, the hardness of the sample was measured using a durometer (D-type durometer).

[0164] (3) 440 nm transmittance

[0165] The transmittance of the window block at a wavelength of 440 nm was measured using a UV-Vis spectrophotometer (UV-2450, Shimadzu).

[0166] The test results are shown in Table 1 and Figure 1 below.

[0167]

[0168] Classification Ref. W-1 W-2 PTMEG:PPG 1:10:20:2 (High molecular weight PPG) Hardness (Shore D) 62.65 735.64 40 nm Transmittance (%) 67.67 2.877

[0169]

[0170] As shown in Table 1 and Figure 1 above, it was confirmed that the window blocks (W-1, W-2) of Examples 1 and 2 exhibited a higher transmittance compared to the window block (Ref) of Comparative Example 1, while maintaining a hardness above a certain level.

[0171]

[0172] Test Example 2: Evaluation of Window Block for Grinding Pad (After Surface Processing)

[0173] The surface of the window blocks prepared in the above examples and comparative examples was processed using processing equipment to a roughness level of Ra 0.5 to 1.0 μm. Subsequently, the surface-processed windows were tested for roughness (Ra), hardness (Shore D), and 440 nm transmittance in the same manner as in Test Example 1. The test results are shown in Table 2 and Figure 2 below.

[0174]

[0175] W-1 Thickness 2mm 1.5mm 1.3mm 1mmRa Roughness (μm) 0.50 10.55 20.54 70.559 Hardness (Shore D) 60.9 62.8 64.2 62.54 40 nm Transmittance (%) 33.5 32.3 63 5.58 32.84

[0176]

[0177] As shown in Table 2 and Figure 2 above, it was confirmed that the window (W-1) of Example 1 maintains a certain level of transmittance and hardness even when surface-processed with an Ra roughness of 0.5 μm or more within a thickness range of 1.0 mm to 2.0 mm.

[0178]

[0179] Example of manufacturing a polishing pad

[0180] Step (1) Preparation of urethane-based prepolymer

[0181] 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), dicyclohexylmethane diisocyanate (H12MDI), polytetramethylene ether glycol (PTMEG), and diethylene glycol (DEG) were added to a 4-neck flask and reacted at 80°C for 3 hours to prepare a urethane-based prepolymer having a terminal NCO group content (NCO%) of 10 wt%.

[0182] Step (2) Manufacturing of the top pad

[0183] A casting device was prepared equipped with tanks and input lines for supplying raw materials such as the above-mentioned urethane-based prepolymer, curing agent, and inert gas. Specifically, the urethane-based prepolymer prepared in step (1), the curing agent (4,4'-methylenebis(2-chloroaniline); MOCA), the solid foaming agent, the inert gas (N2), and the silicone-based surfactant were filled into their respective tanks. Specifically, 32 parts by weight of the curing agent, 1 part by weight of the solid foaming agent, and 1 part by weight of the surfactant were filled relative to 100 parts by weight of the above-mentioned prepolymer, and the inert gas was introduced at a rate of 1.5 L / min.

[0184] The raw materials were fed into the mixing head at a constant speed through each input line while being stirred. The rotation speed of the mixing head was set to approximately 5,000 rpm. After the mixture of the raw materials was mixed in the mixing head, it was injected into a mold measuring 1,000 mm in width, 1,000 mm in length, and 3 mm in height. The temperature of the mold was controlled to approximately 80 (±5)°C. The mixture solidified and cured within the mold to form a sheet. The sheet was then subjected to a process of cutting and forming multiple concentric grooves using a tip to obtain a top pad with an average thickness of 2 mm.

[0185] Step (3) Manufacturing of the polishing pad

[0186] After attaching an adhesive tape to the opposite side of the grooved surface of the top pad obtained in step (2) above, a hole to be inserted for the window block was drilled. A lower pad impregnated with polyurethane resin in a polyester fiber nonwoven fabric was prepared, an adhesive tape was attached, and then bonded to the adhesive tape of the top pad. In the lower pad, a hole was drilled at a position corresponding to the hole in the top pad. Subsequently, the window block was inserted into the hole in the top pad.

Claims

1. Includes a top pad having one or more window blocks, and The above window block comprises polyurethane resin, and The above polyurethane resin includes an isocyanate component and a polyol component, and The above polyol component comprises 60 mol% or more of the compound of the following formula (1), Polishing pad: (1) Here R is an alkyl having 1 to 6 carbon atoms, and n is an integer from 500 to 3000.

2. In Paragraph 1, A polishing pad in the above formula (1), where R is methyl or ethyl and n is 800 to 1200.

3. In Paragraph 1, The above polyol component is A polishing pad containing 90 mol% or more of the compound of the above formula (1).

4. In Paragraph 1, A polishing pad in which the above polyol component does not contain or contains 10 mol% or less of the compound of the following formula (2): (2) Here p is an integer from 1 to 3, and m is an integer between 500 and 3000.

5. In Paragraph 1, The above window block is It has a thickness of 1.0 mm to 2.0 mm, A polishing pad having a transmittance of 30% or more for light with a wavelength of 440 nm.

6. In Paragraph 1, The above window block is The Ra roughness is 0.4 μm to 0.7 μm, and Abrasive pad having a hardness of 40 Shore D to 80 Shore D.

7. Includes polyurethane resin, The above polyurethane resin includes an isocyanate component and a polyol component, and The above polyol component contains 60 mol% or more of the compound of the following formula (1), and Window block for abrasive pads with a transmittance of 30% or more: (1) Here R is an alkyl having 1 to 6 carbon atoms, and n is an integer from 500 to 1500.

8. In Paragraph 7, In the above formula (1), R is methyl or ethyl and n is 800 to 1200, and The above polyol component is The compound of the above formula (1) comprises 90 mol% or more, Window block for a polishing pad that does not contain or contains 10 mol% or less of the compound of formula (2) below: (2) Here p is an integer from 1 to 3, and m is an integer between 500 and 3000.

9. In Paragraph 7, The window block for the polishing pad above is The transmittance for light with a wavelength of 440 nm is 70% or higher, and Window block for abrasive pads having a hardness of 40 Shore D to 80 Shore D.

10. A step of manufacturing a window block using an isocyanate component, a polyol component, and a curing agent; and The above window block includes the step of combining with a top pad and surface processing, The above polyol component comprises 60 mol% or more of the compound of the following formula (1), Method for manufacturing a polishing pad: (1) Here R is an alkyl having 1 to 6 carbon atoms, and n is an integer from 500 to 3000.

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