Polishing pad for maintaining transmittance, and manufacturing method therefor

Abstract

A polishing pad according to one implementation comprises: a top pad having three or more through holes and a plurality of grooves; and a window block inserted into the lower portion of each through hole, wherein the upper portion of the through hole, which is not filled with the window block, has a recess, the ratio of the depth of the recess to the thickness of the top pad is 0.1 to 0.4, and the recess is connected to the grooves. The polishing pad according to the implementation minimizes the occurrence of scratches on a window surface during a CMP process, and facilitates the discharge of polishing residues through the grooves such that a degradation in transmittance caused by the scratches and the residues can be prevented.

Description

Polishing pad for maintaining transmittance and method for manufacturing the same

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

[0002] 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.

[0003] 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. Generally, the top pad and the window block are manufactured as a single integrated unit with the same thickness.

[0004] For example, Korean Patent Registration No. 1203789 discloses a polishing pad in which the thickness of the window block and the top pad are the same. With this structure, if the wear levels of the window block and the top pad differ, a step difference occurs during use, and in most cases, a problem arises where the window is formed too high. In addition, residue generated during polishing accumulates on the window block, which reduces polishing efficiency. Furthermore, scratches occur on the window surface due to friction from the conditioner, and as a result, thickness measurements through the window cannot be accurately performed, leading to frequent situations where the polishing pad must be replaced even though its actual service life remains.

[0005] Meanwhile, the recent application of multiple windows to polishing pads aims to improve the accuracy of thickness measurement compared to the existing single-window structure. This structure enhances process stability and minimizes measurement errors through the mutually complementary roles of each window. Furthermore, since the three windows are separated, scratches or damage that may occur on each window can be managed independently, contributing to extending the overall lifespan of the polishing pad. This improves process stability and efficiency, maintains polishing quality, and contributes to reducing production costs.

[0006] [Prior Art Literature]

[0007] [Patent Literature]

[0008] (Patent Document 1) Korean Patent Registration No. 1203789 (Nov. 15, 2012)

[0009] As a result of research conducted by the inventors to solve these problems, it was possible to implement a polishing pad with a structure that minimizes scratches on the window surface during the CMP process and facilitates the discharge of polishing residue.

[0010] Accordingly, the objective of the present invention is to provide a polishing pad capable of maintaining the transmittance of a polishing pad used in a CMP process at an excellent level, and a method for manufacturing the same.

[0011] According to one embodiment, a polishing pad is provided, comprising: a top pad having three or more through holes and a plurality of grooves; and a window block inserted into the lower portion of each of the through holes, wherein the upper portion of the through holes that is not filled with the window block forms a groove, the ratio of the depth of the groove to the thickness of the top pad is 0.1 to 0.4, and the groove is connected to the groove.

[0012] According to another embodiment, a method for manufacturing a polishing pad is provided, comprising the steps of: manufacturing a top pad having three or more through holes and a plurality of grooves; joining the top pad to a lower pad; and inserting a window block into the lower portion of the through holes of each top pad, wherein the upper portion of the through holes that is not filled with the window block forms a groove, the ratio of the depth of the groove to the thickness of the top pad is 0.1 to 0.4, and the groove is connected to the groove.

[0013] The polishing pad according to the above embodiment minimizes the occurrence of scratches on the window surface during the CMP process and facilitates the discharge of polishing residue through the grooves, thereby preventing a decrease in transmittance caused by scratches and residue. Accordingly, the polishing pad according to the above embodiment maintains the transmittance of the window during the CMP process, thereby increasing the accuracy of thickness measurement and extending the service life of the polishing pad, which can significantly improve the efficiency and stability of the process.

[0014] In addition, the polishing pad according to the above embodiment has excellent airtightness between the top pad and the window, so it has improved sealing characteristics, which can suppress leakage of slurry during polishing processes such as CMP.

[0015] FIG. 1 shows a window arrangement structure of a polishing pad according to one embodiment.

[0016] Figure 2 shows a window arrangement structure of a polishing pad according to the prior art.

[0017] FIG. 3 shows a method of inserting a window block into a polishing pad according to one embodiment.

[0018] FIG. 4 shows a plan view of a polishing pad according to one embodiment.

[0019] Figure 5 is a photograph of the window (thickness 1.5 mm) area after leakage evaluation in Test Example 1.

[0020] Figure 6 is a photograph of the window area (thickness 1.3 mm) after the leakage evaluation in Test Example 1.

[0021] Figure 7 shows the initial transmittance spectrum prior to CMP measured in Test Example 2.

[0022] Figure 8 shows the final transmittance spectrum after CMP measured in Test Example 2.

[0023]

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] Polishing pad

[0032] FIG. 1 shows a window arrangement structure of a polishing pad according to one embodiment. FIG. 4 shows a plan view of a polishing pad according to one embodiment.

[0033] Referring to FIGS. 1 and 4, a polishing pad according to one embodiment includes a top pad (100) having three or more through holes and a plurality of grooves (110); and a window block (200) inserted into the lower part of each of the through holes.

[0034] According to the above embodiment, the upper portion of the through hole that is not filled with the window block (200) forms a groove, and the ratio of the depth of the groove to the thickness of the top pad (100) is 0.1 to 0.4, and the groove is connected to the groove (110).

[0035] In addition, the polishing pad may further include a lower pad (400) bonded to the lower surface of the top pad (100).

[0036] The lower pad (400) may have a through hole corresponding to each through hole of the top pad (100).

[0037] In addition, an adhesive layer (300) may be inserted between the top pad (100) and the bottom pad (400).

[0038] The polishing pad according to the above embodiment minimizes the occurrence of scratches on the window surface during the CMP process and facilitates the discharge of polishing residue through the grooves, thereby preventing a decrease in transmittance caused by scratches and residue. Accordingly, the polishing pad according to the above embodiment maintains the transmittance of the window during the CMP process, thereby increasing the accuracy of thickness measurement and extending the service life of the polishing pad, which can significantly improve the efficiency and stability of the process.

[0039] On the other hand, Fig. 2 shows a window arrangement structure of a polishing pad according to the prior art.

[0040] Referring to FIG. 2, the polishing pad according to the prior art is manufactured such that the thickness of the window block (200) is the same as the thickness of the top pad (100). In this structure, if the wear levels of the window block and the top pad differ, a step difference occurs during use, and in most cases, a problem arises where the window is formed too high. In addition, residue generated during polishing accumulates on the window, which reduces polishing efficiency. Furthermore, scratches occur on the surface of the window due to friction from the conditioner, and as a result, the thickness measurement through the window is not accurate, so the polishing pad frequently needs to be replaced even though there is still a remaining service life.

[0041] The structure of a polishing pad according to one embodiment is described in detail below.

[0042] Window Block

[0043] A window block inserted into the through hole of the top pad serves to detect the polishing endpoint of the wafer to be polished. Specifically, the flatness and thickness of the wafer surface can be measured in real time through the window block, and the polishing endpoint of the wafer can be determined based on the measurement results.

[0044] Referring to FIGS. 1 and 4, the top pad (100) includes three or more through holes and a window block (200) inserted into the lower part of each through hole.

[0045] In this way, the polishing pad may have a full vision window structure in which three or more windows are arranged at equal intervals.

[0046] A polishing pad with a full-vision window structure having three or more windows according to the above embodiment can improve the accuracy of thickness measurement compared to a structure having only one window. This structure can increase process stability and minimize measurement errors through mutually complementary roles between the windows. In addition, since the three or more windows are separated, scratches or damage that may occur on each window can be managed independently, thereby contributing to extending the overall lifespan of the polishing pad. Through this, process stability and efficiency are improved, and while maintaining polishing quality, it can also contribute to reducing production costs.

[0047] The polishing pad according to the above embodiment has three or more window blocks, for example, three to six, three to five, or three to four.

[0048] In the polishing pad, each of the window blocks may be spaced apart from each other at equal angular intervals. For example, if three window blocks are provided in the polishing pad, each of the window blocks may be spaced apart at intervals of 120 degrees.

[0049] In addition, the distance between each of the above window blocks and the center of the surface of the top pad may be the same. For example, the window blocks may be positioned at a distance from the center of the surface of the top pad that is 1 / 5 to 4 / 5 of the diameter of the top pad.

[0050] 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.

[0051] 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.

[0052] The ratio of the thickness of the window block (200) to the thickness of the top pad (100) (i.e., the ratio of the thickness of the window block to the thickness of the top pad) may be, for example, 0.5 or more, 0.6 or more, or 0.7 or more, and may also be 0.9 or less, 0.8 or less, or 0.7 or less, and specifically, may be 0.5 to 0.9, 0.5 to 0.8, 0.5 to 0.7, 0.6 to 0.9, 0.6 to 0.8, 0.6 to 0.7, 0.7 to 0.9, or 0.7 to 0.8.

[0053] In addition, since the thickness of the top pad is equal to the depth of the through hole formed in the top pad (i.e., the hole into which the window block is inserted), the ratio of the thickness of the window block to the thickness of the top pad exemplified above is equal to the ratio of the thickness of the window block to the depth of the through hole (i.e., the ratio of the thickness of the window block to the depth of the through hole).

[0054] Referring to FIG. 1, the upper portion of the through hole of the top pad (100) that is not filled with the window block (200) forms a groove.

[0055] In one embodiment, the ratio of the depth of the groove to the thickness of the top pad (100) (i.e., the ratio of the groove depth to the top pad thickness) is 0.1 to 0.4.

[0056] For example, the ratio of the depth of the groove to the thickness of the top pad may be 0.1 or more, 0.15 or more, 0.2 or more, or 0.25 or more, and may also be 0.4 or less, 0.35 or less, 0.3 or less, or 0.25 or less, and specifically, may be 0.1 to 0.4, 0.1 to 0.35, 0.1 to 0.3, 0.1 to 0.25, 0.15 to 0.4, 0.15 to 0.35, 0.15 to 0.3, 0.15 to 0.25, 0.2 to 0.4, 0.2 to 0.35, 0.2 to 0.3, 0.2 to 0.25, 0.25 to 0.4, 0.25 to 0.35, or 0.25 to 0.3.

[0057] In addition, since the thickness of the top pad is equal to the depth of the through hole formed in the top pad, the ratio of the depth of the groove to the thickness of the top pad exemplified above is equal to the ratio of the depth of the groove to the depth of the through hole (i.e., the ratio of the depth of the groove to the depth of the through hole).

[0058] 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. In one embodiment, the window block may have a thickness of 1.2 mm to 1.6 mm.

[0059] Within the thickness range of the window block exemplified above, it is more advantageous to prevent a decrease in transmittance caused by scratches and residues on the window surface during the CMP process.

[0060] The above 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. Accordingly, the above window block may not have pores.

[0061] The specific composition and method of manufacturing the above window block may be the same as the composition and method of manufacturing the top pad described below, except that a foaming agent is not used.

[0062] The light transmittance of the window block (e.g., transmittance for light of a wavelength of 440 nm) may be, for example, 20% or more, 25% or more, 30% or more, 40% or more, or 50% or more, and specifically, 50% to 85%, 55% to 80%, or 60% to 80%. 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 light transmittance and the refractive index are within the above ranges, the polishing endpoint of the wafer can be detected more accurately.

[0063] 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.

[0064] 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.

[0065] The surface roughness of the window block can be adjusted within a certain range for transparency. For example, the Ra roughness of the window block may be 0.5 μm or more, 1.0 μm or more, or 5 μm or more, and may also be 3.0 μm or less, 2.5 μm or less, or 2.0 μm or less. In one embodiment, the Ra roughness of the window block may be 0.5 μm to 3.0 μm.

[0066] Groove

[0067] Referring to FIG. 4, a polishing pad according to one embodiment has a plurality of grooves (110) on the top pad (100).

[0068] The groove formed in the top pad is connected to the upper groove in the through hole of the top pad that is not filled with the window block. Accordingly, the discharge of polishing residue through the groove during the CMP process is facilitated, thereby preventing a decrease in transmittance caused by scratches and residue.

[0069] The depth of the groove of the top pad may be equal to or smaller than the depth of the groove. Alternatively, the depth of the groove of the top pad may be equal to or greater than the depth of the groove.

[0070] In one embodiment, the top pad may have a plurality of first grooves having a concentric shape.

[0071] The first grooves may be provided in multiple numbers and spaced apart from each other at regular intervals. Specifically, the spacing between the multiple first grooves may be 1 mm to 10 mm, 1 mm to 5 mm, or 2 mm to 4 mm.

[0072] The width of the first groove may be, for example, 0.1 mm or more, 0.2 mm or more, or 0.3 mm or more, and may also be 1 mm or less, 0.9 mm or less, or 0.8 mm or less, and as a specific example, 0.1 mm to 1 mm. The depth of the first groove may be, for example, 0.4 mm or more, 0.5 mm or more, or 0.6 mm or more, and may also be 1.2 mm or less, 1.1 mm or less, or 1.0 mm or less, and as a specific example, 0.4 mm to 1.2 mm.

[0073] Additionally, the depth of the first groove may be 70% or less of the thickness of the top pad. Specifically, the depth of the second groove may be 50% or less or 30% or less of the thickness of the top pad. More specifically, the depth of the first groove may be 10% to 60%, 20% to 50%, or 30% to 50% of the thickness of the top pad. Within the above range, the fluidity of the slurry can be further improved while preventing deformation of the top pad due to groove formation.

[0074] According to another embodiment, the top pad includes at least one of a plurality of first grooves having a concentric shape and a plurality of second grooves having a radial straight shape, and the first groove and the second groove may be connected to a groove formed on the upper part of the through hole.

[0075] The first grooves may be provided in multiple numbers and spaced apart from each other at a certain distance, and the second grooves may be provided in multiple numbers and spaced apart from each other at a certain angle. Specifically, the spacing angle between the multiple second grooves may be 10° to 50°, 15° to 45°, or 20° to 40°.

[0076] As an example, the planar shape of the second groove may be a plurality of radial straight lines formed at intervals of a certain angle from the center to the outer edge. As another example, the planar shape of the second groove may be a straight line formed radially from a point 10% to 90% of the radius away from the center of the top pad to the outer edge.

[0077] The width of the second groove may be, for example, 0.5 mm or more, 0.6 mm or more, or 0.7 mm or more, and may also be 1.5 mm or less, 1.4 mm or less, or 1.3 mm or less, and as a specific example, may be 0.5 mm to 1.5 mm. The depth of the second groove may be, for example, 0.5 mm or more, 0.6 mm or more, or 0.7 mm or more, and may also be 1.5 mm or less, 1.4 mm or less, or 1.3 mm or less, and as a specific example, may be 0.5 mm to 1.5 mm.

[0078] In one embodiment, the width of the first groove may be 0.1 mm to 1 mm, and the width of the second groove may be 0.5 mm to 1.5 mm. In another embodiment, the depth of the first groove may be 0.4 mm to 1.2 mm, and the depth of the second groove may be 0.5 mm to 1.5 mm.

[0079] The depth of the second groove may be the same as or deeper than the depth of the first groove. For example, the depth of the second groove may be 100% to 300% of the depth of the first groove. Or, the depth of the second groove may be greater than 100% to 300% or less of the depth of the first groove, or greater than 100% to 250% or less. Or, the depth of the second groove may be 110% to 300% of the depth of the first groove, for example, 120% to 300%, for example, 120% to 200%, for example, 125% to 150%. When within the above range, the fluidity of the slurry is improved so that the discharge of waste generated during the polishing process can occur more efficiently, and at the same time, when polishing a wafer using the polishing pad, defects on the polished surface can be minimized while securing an appropriate polishing rate.

[0080] Additionally, the depth of the second groove may be 90% or less of the thickness of the top pad. Specifically, the depth of the second groove may be 70% or less or 50% or less of the thickness of the top pad. More specifically, the depth of the second groove may be 10% to 60%, 20% to 50%, or 30% to 50% of the thickness of the top pad. Within the above range, the fluidity of the slurry can be further improved while preventing deformation of the top pad due to groove formation.

[0081] The width of the second groove may be 50% to 200% of the width of the first groove. Specifically, the width of the second groove may be 100% to 200% of the width of the first groove. Alternatively, the width of the second groove may be 100% to 180% of the width of the first groove, for example, 100% to 170%, for example, 100% to 165%, for example, 100% to 160%. Within the above range, it is advantageous to improve the fluidity of the slurry while securing a sufficient grinding area.

[0082]

[0083] Top pad

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] The top pad has three or more through holes and a plurality of grooves, and the through holes and grooves are as described above.

[0098] Other components

[0099] The polishing pad further includes a lower pad bonded to the lower surface of the top pad, and the lower pad may have a through hole corresponding to each through hole of the top pad.

[0100] 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.

[0101] The above lower pad may include non-woven fabric or suede, but is not limited thereto.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] In addition, an adhesive layer may be inserted between the top pad and the bottom pad.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] Characteristics of the polishing pad

[0111] The polishing pad according to the above embodiment minimizes the occurrence of scratches on the window surface during the CMP process and facilitates the discharge of polishing residue through the grooves, thereby preventing a decrease in transmittance caused by scratches and residue.

[0112] In one embodiment, chemical mechanical polishing (CMP) is performed on a silicon oxide film of a wafer for 1 minute under conditions of a polishing load of 4.0 psi and a polishing pad rotation speed of 150 rpm while supplying a silica slurry to the polishing pad at a rate of 250 mL / min, and the transmittance of the window block is 6.0% or more at a wavelength of 440 nm when measured.

[0113] Specifically, after performing a CMP process under the above conditions for 1 minute, when measuring the transmittance of the window block, it may be 6% or more, 6.5% or more, or 7% or more at a wavelength of 440 nm, and more specifically, 6% to 50%, 6% to 30%, 6% to 20%, or 6% to 10%.

[0114] In addition, the difference in transmittance of the window block at a wavelength of 440 nm (i.e., transmittance before CMP - transmittance after CMP) compared to before performing the CMP process under the above conditions for 1 minute may be 50% or less, 30% or less, 25% or less, 20.2% or less, 20.1% or less, or 20% or less, and more specifically, 0% to 30%, 0% to 25%, 0% to 20.2%, 0% to 20.1%, 0% to 20%, 10% to 30%, 10% to 25%, 10% to 20.2%, 10% to 20.1%, or 10% to 20%.

[0115] The polishing pad according to the above embodiment has excellent airtightness between the top pad and the window, so it has improved sealing characteristics, and thus can suppress leakage of slurry during polishing processes such as CMP.

[0116] In one embodiment, the polishing pad has a pressure difference (ΔP) of 3 mbar or less according to the following formula.

[0117] ΔP = P1 - P2

[0118] Here, P1 is the pressure (mbar) applied to the through hole into which the window block is inserted in the top pad in a sealed state, and P2 is the pressure (mbar) measured after applying the pressure of P1 to the through hole for 5 minutes in a sealed state.

[0119] A test in such a tight seal can be performed by positioning the window block insertion part of the polishing pad on a support, installing a tight seal test device equipped with a 10 cm diameter circular connector with sealing on the edge on the part where the through hole is formed in the lower pad, applying pressure through the tight seal test device, and measuring the pressure after 5 minutes.

[0120] The polishing pad according to the above embodiment may have a pressure difference (ΔP) according to the above formula, for example, 0 mbar to 3 mbar, 0.1 mbar to 3 mbar, or 1 mbar to 3 mbar.

[0121] Method for manufacturing a polishing pad

[0122] A method for manufacturing a polishing pad according to one embodiment includes: (1) manufacturing a top pad having three or more through holes and a plurality of grooves; (2) joining the top pad to a lower pad; and (3) inserting a window block into the lower part of each of the through holes of the top pad.

[0123] Each step is explained in detail below.

[0124] In step (1) above, a top pad having three or more through holes and a plurality of grooves is manufactured.

[0125] The above top pad may include a urethane-based polymer prepared from a composition comprising a urethane-based prepolymer, a curing agent, a foaming agent, and other additives.

[0126] The above 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 can 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.

[0127] The curing agent may be one or more of amine compounds and alcohol compounds. Specifically, the curing agent may include one or more compounds selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols.

[0128] The above-mentioned foaming agent is not particularly limited as long as it is commonly used for forming pores in a polishing pad. For example, the above-mentioned foaming agent may be one or more selected from solid foaming agents having a hollow structure, liquid foaming agents using volatile liquids, and inert gases.

[0129] The manufacturing step of the top pad above includes a groove forming step and a through hole forming step.

[0130] In one embodiment, the manufacturing step of the top pad includes, in sequence, a groove forming step and a through hole forming step.

[0131] The formation of the groove can be performed by cutting and removing a portion of the surface of the top pad. For example, the formation of the groove can be performed using a tip. A portion of the surface of the top pad can be removed by the tip to form a groove. Specifically, after fixing the tip in contact with the surface of the top pad, a grinding pad including the top pad can be rotated or moved in a desired direction to remove a portion of the top pad surface and form a groove.

[0132] 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.

[0133] The grooves and through holes of the top pad are formed to be connected to each other (i.e., at least some of the grooves pass through the through holes).

[0134] In one embodiment, the groove forming step comprises at least one step among a plurality of first grooves having a concentric shape and a plurality of second grooves having a radial straight shape, and the first groove and the second groove may be formed to be connected to the through hole.

[0135] In step (2) above, the top pad is joined to the bottom pad.

[0136] A polishing pad according to one embodiment has three or more through holes (first through holes) in the top pad and, correspondingly, three or more through holes (second through holes) in the lower pad.

[0137] Accordingly, after the top pad and the lower pad are joined, the through hole (first through hole) of the top pad and the through hole (second through hole) of the lower pad become connected to each other.

[0138] The through hole of the lower pad may be formed before or after joining with the top pad. As an example, the through hole of the lower pad may be formed after joining with the top pad.

[0139] The through hole (second through hole) of the lower pad can be formed to have a smaller diameter than the through hole (first through hole) of the top pad. By making the diameters of the through holes different in this way, the airtightness between the top pad and the window can be improved, which is advantageous for suppressing leakage of slurry during polishing processes such as CMP.

[0140] The above bonding can be performed after applying an adhesive or adhesive tape to the lower surface of the top pad (i.e., the surface opposite to where the groove is formed) and the upper surface of the lower pad, respectively. The adhesive or adhesive tape can be applied to the portion of the lower surface of the top pad and the upper surface of the lower pad that does not have a through hole.

[0141] FIG. 3 shows a method of inserting a window block into a polishing pad according to one embodiment.

[0142] Referring to FIG. 3, in step (3), a window block (200) is inserted into the lower part of the through hole of each top pad (100).

[0143] 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 the curing agent into a mold, for example, at 80°C to 100°C, curing it for 10 to 60 minutes, and then post-curing it in an oven at 80°C to 120°C for 12 to 48 hours. Subsequently, the window sheet can be cut to adjust the thickness, and the surface roughness can be adjusted to a range of 0.5 μm to 3.0 μm based on the Ra value using equipment such as a tip.

[0144] 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.

[0145] In one embodiment, the thickness of the window block is smaller than the depth of the through hole.

[0146] After the above window block is inserted into the lower part of the through hole, the lower surface of the window block may align with the lower surface of the top pad.

[0147] After insertion of the window block, the upper part of the through hole that is not filled with the window block forms a groove, and the ratio of the depth of the groove to the thickness of the top pad is 0.1 to 0.4, and the groove is connected to the groove.

[0148] Before insertion, adhesive may be applied in advance to the area where the window block contacts the top pad and / or bottom pad.

[0149] 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.

[0150] Method for manufacturing a semiconductor device

[0151] 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.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] 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.

[0160] [Example]

[0161] The following embodiments are described, but the scope of implementation is not limited to these.

[0162] Example 1: Manufacture of a polishing pad (window block thickness 1.5 mm)

[0163] Step (1) Preparation of urethane-based prepolymer

[0164] 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%.

[0165] Step (2) Manufacturing of the top pad

[0166] 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.

[0167] 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.

[0168] Step (3) Manufacturing of the polishing pad

[0169] After attaching an adhesive tape to the side opposite to the grooved surface of the top pad obtained in step (2) above, three circular holes with a diameter of 20 mm were perforated at 120-degree intervals. 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, circular through holes with a diameter of 12 mm were formed at positions corresponding to each of the three through holes of the top pad. Subsequently, an adhesive was applied to the surface of the lower pad exposed to the through holes of the top pad, and a window block was inserted into the lower part of the through holes of the top pad. The window block was manufactured by repeating the same procedure as the top pad in steps (1) and (2) above, but without adding a solid foaming agent or inert gas to obtain a non-foamed body, and then processed to a diameter of 20 mm and a thickness of 1.5 mm for use.

[0170] The resulting polishing pad had a groove formed in the upper part of the through hole formed in the top pad where the window block was not filled, the ratio of the depth of the groove to the thickness of the top pad was 0.25, and the groove had a structure connected to the groove.

[0171] Example 2: Manufacture of a polishing pad (window block thickness 1.3 mm)

[0172] A polishing pad was manufactured by repeating the same procedure as in Example 1 above, but changing the thickness of the window block to 1.3 mm. The resulting polishing pad had a groove formed in the upper part of the through hole formed in the top pad where the window block was not filled, the ratio of the depth of the groove to the thickness of the top pad was 0.35, and the groove had a structure connected to the groove.

[0173] Comparative Example 1: Manufacture of a polishing pad (window block thickness 1.0 mm)

[0174] A polishing pad was manufactured by repeating the same procedure as in Example 1 above, but changing the thickness of the window block to 1.0 mm. The resulting polishing pad had a groove formed in the upper part of the through hole formed in the top pad where the window block was not filled, the ratio of the depth of the groove to the thickness of the top pad was 0.5, and the groove had a structure connected to the groove.

[0175] Comparative Example 2: Manufacture of a polishing pad (window block thickness 2.0 mm)

[0176] The same procedure as in Example 1 above was repeated, but the thickness of the window block was changed to 2.0 mm to manufacture a polishing pad. As a result, the polishing pad obtained had no groove formed because the window block completely filled the through hole formed in the top pad.

[0177] Test Example 1: Leakage Evaluation

[0178] Leakage evaluation was performed on the polishing pads of the above examples and comparative examples using CTS’s AP-300 equipment. The evaluation was conducted by flowing only distilled water without using wafer slurry, and a conditioner with high wear was used. In addition, although wafers were not used, the evaluation was conducted by increasing the carrier pressure to approximately 9 bar, which is higher than usual. The total evaluation was conducted for 8 hours, and the evaluation was carried out by visually checking for leakage in the window every hour.

[0179] The results are shown in Table 1 below. In addition, photos of the window area after evaluation are shown in Figures 3 and 4.

[0180] Leakage Status Time (hr) Example 1 (Window thickness 1.5 mm) Example 2 (Window thickness 1.3 mm) 1XX2XX3XX4XX5XX6XX7XX8XX

[0181]

[0182] As shown in Table 1 above, no leakage was detected in the polishing pads of Examples 1 and 2 for 1 to 8 hours as a result of the leakage evaluation.

[0183] Test Example 2: Leak Evaluation

[0184] Leakage evaluation was performed on the polishing pads of the above examples and comparative examples. The window block insertion portion of the polishing pad was positioned on a support, and a leak test device equipped with a 10 cm diameter circular connector with sealing on the rim was installed in the portion of the lower pad where the through hole was formed. Subsequently, pressure was applied through the leak test device, and the pressure was measured after 5 minutes. Then, ΔP was calculated according to the following equation.

[0185] ΔP = P1 - P2

[0186] Here, P1 is the pressure (mbar) applied to the through hole into which the window is inserted in the top pad in a sealed state, and P2 is the pressure (mbar) measured after applying the pressure of P1 to the through hole for 5 minutes in a sealed state.

[0187] Leakage evaluation was performed by preparing two samples per polishing pad of each example and comparative example, and the results are summarized in Tables 2 to 4 below. In addition, if ΔP is 3 mbar or less, it was indicated as passing (O) in the leakage evaluation.

[0188] NO. Example 1 (Window thickness 1.5 mm) Leakage Pass / Fail ΔP (mbar) Sample 1 Sample 2 Sample 1 Sample 2 100.9 21.8 9200.5 12.0 2300.5 92.4 9400.1 380.3 9500.9 1.6 3600.4 82.1 6700.6 500.8 2800.4 40.7 6900.9 50.6 5 Average Pass / Fail Pass / Fail 0.7 61.4 2

[0189]

[0190] NO. Example 2 (Window thickness 1.3 mm) Leakage Pass / Fail ΔP (mbar) Sample 1 Sample 2 Sample 1 Sample 2 100.96 1.02 200.62 1.83 300.2 10.93 400.15 41.18 500.15 41.14 600.19 51.2700.88 1.018 1.55 1.13 900.95 0.92 Average Pass / Fail 1.36 1.15

[0191]

[0192] NO. Comparative Example 1 (Window thickness 1.0 mm) Leakage Pass / Fail ΔP (mbar) Sample 1 Sample 2 Sample 1 Sample 2 1XX--2XX--3XX--4XX--5XX--6XX--7XX--8XX--9XX--Average Fail Fail--

[0193]

[0194] As shown in Tables 2 to 4 above, the polishing pads of Examples 1 and 2 were excellent in the leakage evaluation, with ΔP measured at 3 mbar or less. On the other hand, the polishing pad of Comparative Example 1 had severe leakage, so ΔP could not be measured.

[0195] Test Example 3: Evaluation of Window Transmittance During CMP Process

[0196] The window transmittance during the CMP process was evaluated using the polishing pads of the above examples and comparative examples.

[0197] (1) CMP process

[0198] After installing a silicon wafer with a diameter of 300 mm, on which silicon oxide was deposited by a CVD process, in a CMP polishing machine, the silicon oxide film of the silicon wafer was placed facing downward on a platen to which the porous polyurethane polishing pad was attached. Subsequently, the silicon oxide film was polished for 1 minute under conditions of a polishing load of 4.0 psi and a polishing pad rotation speed of 150 rpm while introducing a silica slurry onto the polishing pad at a rate of 250 mL / min.

[0199] (2) Window transmittance evaluation

[0200] Before and after the above CMP process, only the window block was separated from the top pad, and the transmittance in the wavelength range of 300 nm to 800 nm was measured.

[0201] (3) Test results

[0202] When performing a CMP process using the polishing pad of Example 2 (window thickness 1.3 mm) and the polishing pad of Comparative Example 2 (window thickness 2.0 mm), the results of measuring the initial transmittance before polishing and the final transmittance after polishing are shown in Table 5 below. In addition, the spectrum of the initial transmittance before polishing and the spectrum of the final transmittance after polishing are shown in Figures 7 and 8, respectively.

[0203] Classification Window 440 nm Transmittance (%) Example 2 (Window thickness 1.3 mm) Comparative Example 2 (Window thickness 2.0 mm) Before CMP 27.1 26.1 After CMP 7.1 5.8

[0204]

[0205] Referring to Table 5 and Figures 7 and 8 above, the polishing pad of Example 2 had superior performance in maintaining the transmittance of the window at a wavelength of 440 nm before and after CMP compared to the polishing pad of Comparative Example 2.

[0206] [Explanation of the symbol]

[0207] 100: Top Pad, 110: Groove, 200: Window Block,

[0208] 300: Adhesive layer, 400: Bottom pad.

Claims

1. A top pad having three or more through holes and a plurality of grooves; and It includes a window block inserted into the lower part of each of the above-mentioned through holes, and In the above through hole, the upper portion that is not filled with the window block forms a groove, and The ratio of the depth of the groove to the thickness of the top pad is 0.1 to 0.4, and The above groove is a polishing pad connected to the above groove.

2. In Paragraph 1, The above window block is a polishing pad having a thickness of 1.2 mm to 1.6 mm.

3. In Paragraph 1, The above polishing pad is A polishing pad having a full vision window structure in which three or more window blocks are arranged at equal intervals.

4. In Paragraph 1, The above polishing pad further includes a lower pad bonded to the lower surface of the above top pad, and The lower pad above is a polishing pad having a through hole corresponding to each through hole of the top pad.

5. In Paragraph 4, The diameter of the through hole in the top pad above is A polishing pad having a diameter of 1.1 to 2.0 times the diameter of the through hole of the lower pad.

6. In Paragraph 1, The above top pad is A plurality of first grooves having the shape of concentric circles, and It includes at least one type among a plurality of second grooves having a radial straight shape, and A polishing pad in which the first groove and the second groove are connected to a groove formed on the upper part of the through hole.

7. In Paragraph 1, The above abrasive pad is an abrasive pad having a pressure difference (ΔP) of 3 mbar or less according to the following formula: ΔP = P1 - P2 Here P1 is the pressure (mbar) applied to the through hole into which the window block is inserted in the top pad in a sealed state, and P2 is the pressure (mbar) measured after applying the pressure of P1 to the above-mentioned through hole for 5 minutes in a sealed state.

8. In Paragraph 1, A polishing pad having a transmittance of 6.0% or more at a wavelength of 440 nm when measuring the transmittance of the window block, after performing chemical mechanical polishing (CMP) on a silicon oxide film of a wafer for 1 minute under conditions of a polishing load of 4.0 psi and a polishing pad rotation speed of 150 rpm while supplying silica slurry to the polishing pad at a rate of 250 mL / min.

9. A step of manufacturing a top pad having 3 or more through holes and a plurality of grooves; A step of joining the above top pad to the lower pad; and The method includes the step of inserting a window block into the lower part of the through hole of each of the top pads. In the above through hole, the upper portion that is not filled with the window block forms a groove, and The ratio of the depth of the groove to the thickness of the top pad is 0.1 to 0.4, and A method for manufacturing a polishing pad in which the above groove is connected to the above groove.

10. A method for manufacturing a semiconductor device, comprising the step of performing chemical mechanical polishing (CMP) on the surface of a semiconductor substrate using the polishing pad of claim 1.

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