Method for recovering surface of polishing pad and polishing pad with low metal contamination

Abstract

Provided is a method of recovering a surface of a polishing pad, the method comprising a step of conditioning a polishing surface of the polishing pad, wherein the conditioning comprises applying steam at 80°C to 110°C to the polishing surface, and when the polishing surface is analyzed by inductively coupled plasma-emission spectroscopy (ICP-OES), the increase in titanium (Ti) content after the conditioning compared to before the conditioning is 100 ppm or less.

Description

Surface recovery method for abrasive pads and abrasive pads with low metal contamination

[0001] An embodiment relates to a method for surface recovery of a polishing pad used in a chemical mechanical polishing (CMP) process of a semiconductor device. Furthermore, the present invention relates to a polishing pad with low metal contamination during conditioning.

[0002]

[0003] Recently, as the individual chip size of semiconductor devices has been miniaturized, chip integration density has increased, and the miniaturization of circuit patterns formed on the chips has become more advanced, the importance of the chemical mechanical polishing (CMP) process is on the rise.

[0004] In the CMP process, a polishing slurry is supplied to a rotating polishing pad, and the supplied polishing slurry is uniformly distributed on the surface of the polishing pad by the rotation of the pad. As the surface of the rotating polishing pad, on which the polishing slurry is distributed, comes into contact with the surface of the rotating polishing target (substrate, semiconductor device, rotary pattern, etc.), polishing of the surface of the polishing target is performed. Chemical polishing is performed on the surface of the polishing target through the polishing slurry. In addition, mechanical polishing is performed on the surface of the rotating polishing target through physical contact with the surface of the rotating polishing pad.

[0005] This CMP process is designed to flatten the surface of an object to be polished or to remove aggregated material, scratches, and contaminants formed on the surface. In this CMP process, polishing pads are used to polish the surface of the object. The polishing pads used in the CMP process are process components that machine the surface of the object to a target level through friction, and they are a factor that determines the uniformity of thickness, flatness, and quality of the surface of the polished object after polishing is complete.

[0006] As the CMP process is repeatedly performed, the polishing performance of these polishing pads deteriorates due to wear. Polishing pads with such degraded performance must be replaced with new ones and subsequently discarded. Consequently, since these degraded pads cannot be reused and are instead discarded, periodic replacement costs are incurred, and environmental pollution caused by their disposal intensifies.

[0007] Accordingly, the importance of conditioning processes is increasing, as they enable the reuse of polishing pads with degraded polishing performance and minimize the amount of discarded pads.

[0008] [Prior Art Literature]

[0009] [Patent Literature]

[0010] (Patent Document 1) Korean Published Patent Application No. 2006-75453 (July 4, 2006)

[0011]

[0012] Since the surface roughness of the polishing pad decreases during the CMP process, a conditioner such as a diamond disc is used to increase the surface roughness; however, in this case, metal contamination occurs due to the conditioner in direct contact with the polishing surface, and the polishing surface may wear out, potentially shortening its lifespan.

[0013] Therefore, the objective of the embodiment is to provide a method and a polishing pad that have excellent surface recovery while minimizing metal contamination during conditioning.

[0014]

[0015] According to one embodiment, a method for restoring the surface of a polishing pad is provided, comprising the step of conditioning the polishing surface of the polishing pad, wherein the conditioning includes applying steam to the polishing surface, and when the polishing surface is analyzed by inductively coupled plasma emission spectrometry (ICP-OES), the increase in titanium (Ti) content after conditioning compared to before conditioning is 100 ppm or less.

[0016] According to another embodiment, a polishing pad is provided that includes a polishing layer having a polished surface, and after conditioning the polished surface by applying steam at 95°C for 10 minutes, when the polished surface is analyzed by inductively coupled plasma emission spectrometry (ICP-OES), the increase in titanium (Ti) content after conditioning compared to before conditioning is 100 ppm or less.

[0017]

[0018] According to the above embodiment, surface recovery is excellent with minimal metal contamination due to conditioning using steam. In addition, the effect can be maximized by combining conditioning using steam with conditioning using a diamond disc or a brush.

[0019] In addition, the polishing pad according to the above embodiment can be applied to the chemical mechanical polishing (CMP) process of a semiconductor device because it has excellent surface recovery properties and low metal contamination after conditioning.

[0020]

[0021] Figures 1 and 2 show the oxide film polishing rate (RR) according to the conditioning method of the polishing pad of Preparation Example 1.

[0022] Figures 3 to 6 show profiles of oxide film polishing rates (RR) according to the conditioning method of the polishing pad of Preparation Example 1.

[0023] Figure 7 shows the surface morphology according to the conditioning method of the polishing pad of Preparation Example 1.

[0024] Figures 8 to 11 show surface images according to the conditioning method of the polishing pad of Preparation Example 1.

[0025]

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033]

[0034] Surface recovery method

[0035] A surface recovery method according to one embodiment includes the step of conditioning the polished surface of a polishing pad.

[0036] The above conditioning includes applying steam to the polished surface.

[0037] Specifically, when steam is used, the temperature of the polished surface increases to a higher level than that caused by frictional heat with the disc used in conventional general conditioning methods, which can further enhance the surface recovery effect of the polished piece. In addition, while metal contamination of the polished surface occurs after conditioning using conventional discs, conditioning using steam can prevent this problem.

[0038] The temperature of the steam applied to the polishing surface may, for example, be 80°C or higher or 90°C or higher, and may also be 110°C or lower or 100°C or lower. Specifically, the temperature of the steam applied to the polishing surface may be 80°C to 110°C, 90°C to 110°C, 80°C to 100°C, or 90°C to 100°C.

[0039] The above steam may be, for example, steam from deionized water (DIW).

[0040] The time for applying steam to the polished surface may be, for example, 1 minute or more, 3 minutes or more, or 5 minutes or more, and may also be 3 hours or less, 1 hour or less, 30 minutes or less, 20 minutes or less, 15 minutes or less, or 10 minutes or less. Specifically, the time for applying steam during conditioning may be 1 minute to 3 hours, 1 minute to 1 hour, 1 minute to 30 minutes, 1 minute to 20 minutes, 3 minutes to 20 minutes, or 5 minutes to 15 minutes.

[0041] The flow rate of steam applied to the polishing surface may be, for example, 50 mL / min or more, 100 mL / min or more, or 150 mL / min or more, and may also be 700 mL / min or less, 500 mL / min or less, or 300 mL / min or less, and specifically may be 50 mL / min to 500 mL / min, or 100 mL / min to 300 mL / min.

[0042] The above conditioning can be performed by placing a polishing pad on a platen and rotating the platen.

[0043] The platen rotation speed during the above conditioning may be, for example, 30 rpm or more, 40 rpm or more, or 50 rpm or more, and may also be 200 rpm or less, 150 rpm or less, or 100 rpm or less, and specifically may be 30 rpm to 200 rpm, or 50 rpm to 100 rpm.

[0044] During the above conditioning, steam may be sprayed from a certain height above the polishing surface. For example, the height at which the steam is sprayed may be 1 cm or more or 2 cm or more above the polishing surface, and may also be 10 cm or less or 5 cm or less, and specifically, 1 cm to 10 cm, or 2 cm to 5 cm.

[0045] In one embodiment, the conditioning can be performed while supplying a polishing slurry onto the polishing surface of the polishing pad. For example, the polishing slurry can be supplied onto the polishing surface through a supply nozzle.

[0046] The flow rate of the polishing slurry supplied to the polishing surface may be, for example, 10 mL / min to 1,000 mL / min, specifically 10 mL / min to 800 mL / min, and more specifically 50 mL / min to 500 mL / min, but is not limited thereto.

[0047] The above polishing slurry may contain polishing particles. For example, the polishing slurry may contain polishing particles in an amount of 0.1 wt% or more, 0.5 wt% or more, 1 wt% or more, or 1.5 wt% or more, and may also contain 10 wt% or less, 5 wt% or less, or 3 wt% or less, and specifically may contain 0.1 wt% to 10 wt%, 0.5 wt% to 5 wt%, or 1 wt% to 3 wt%.

[0048] Since the hardness and friction characteristics of the particles differ depending on the type of abrasive particles mentioned above, there may be differences in the conditioning effect.

[0049] The polishing slurry may include, for example, silica (SiO2) particles or ceria (CeO2) particles. In one embodiment, the polishing slurry may include silica (SiO2) particles.

[0050] In one embodiment, when the polished surface is analyzed by inductively coupled plasma emission analysis (ICP-OES), the increase in titanium (Ti) content after conditioning compared to before conditioning is 100 ppm or less.

[0051] For example, the increase in titanium (Ti) content on the polished surface after the conditioning compared to before the conditioning (i.e., Ti content after conditioning - Ti content before conditioning) may be 100 ppm or less, 50 ppm or less, 30 ppm or less, 20 ppm or less, or 10 ppm or less. Specifically, the increase in titanium (Ti) content on the polished surface after the conditioning compared to before the conditioning may be -50 ppm to 100 ppm, -30 ppm to 100 ppm, -10 ppm to 100 ppm, -30 ppm to 50 ppm, -20 ppm to 50 ppm, -10 ppm to 50 ppm, -20 ppm to 30 ppm, -10 ppm to 30 ppm, or 0 ppm to 30 ppm.

[0052] In another embodiment, when the polished surface is analyzed by inductively coupled plasma emission analysis (ICP-OES), the increase in aluminum (Al) content after conditioning compared to before conditioning may be 10 ppm or less.

[0053] For example, the increase in aluminum (Al) content on the polished surface after the conditioning compared to before the conditioning (i.e., Al content after conditioning - Al content before conditioning) may be 10 ppm or less, 5 ppm or less, 3 ppm or less, 2 ppm or less, or 1 ppm or less. Specifically, the increase in aluminum (Al) content on the polished surface after the conditioning compared to before the conditioning may be -5 ppm to 10 ppm, -3 ppm to 10 ppm, -1 ppm to 10 ppm, -3 ppm to 5 ppm, -2 ppm to 5 ppm, -1 ppm to 5 ppm, -2 ppm to 3 ppm, -1 ppm to 3 ppm, -1 ppm to 2 ppm, -1 ppm to 1 ppm, or 0 ppm to 1 ppm.

[0054] The above conditioning may include sweeping the polishing surface with a disc while applying steam to the polishing surface.

[0055] Specifically, the conditioning may include sweeping the polished surface with a disc while applying steam at 80°C to 110°C to the polished surface.

[0056] In this way, when steam is applied to the polished surface while sweeping with a disc during conditioning, the surface recovery can be excellent with less metal contamination compared to cases where only steam is applied to the polished surface or where only the polished surface is swept with a disc.

[0057] The disc used for the above conditioning may be, for example, a diamond disc. The diamond disc may have a structure in which a number of diamond particles are attached to a base plate made of, for example, metal. Such diamond particles are very hard and highly durable, which can result in high conditioning efficiency. The diamond particles may be arranged in a specific pattern, such as a circle or a hexagon, and this pattern structure can play an important role in optimizing polishing efficiency and the lifespan of the pad.

[0058] The time for sweeping with a disc while applying steam to the above-mentioned polishing surface may be, for example, 1 minute or more, 3 minutes or more, or 5 minutes or more, and may also be 3 hours or less, 1 hour or less, 30 minutes or less, 20 minutes or less, 15 minutes or less, or 10 minutes or less; specifically, it may be 1 minute to 3 hours, 1 minute to 1 hour, 1 minute to 30 minutes, 1 minute to 20 minutes, 3 minutes to 20 minutes, or 5 minutes to 15 minutes.

[0059] When sweeping with a disc while applying steam to the above-mentioned polishing surface, the rotational speed of the platen may be, for example, 20 rpm or more, 30 rpm or more, or 40 rpm or more, and may also be 150 rpm or less, 100 rpm or less, or 70 rpm or less, and specifically may be 20 rpm to 150 rpm, or 30 rpm to 100 rpm.

[0060] In addition, the rotational speed of the disk may be, for example, 30 rpm or more, 40 rpm or more, or 50 rpm or more, and may also be 90 rpm or less, 80 rpm or less, or 70 rpm or less, and specifically may be 30 rpm to 90 rpm, 40 rpm to 80 rpm, or 50 rpm to 70 rpm.

[0061] In addition, the load on the polished surface of the above disk may be, for example, 1 lbf or more, 2 lbf or more, or 3 lbf or more, and may also be 10 lbf or less, 7 lbf or less, or 5 lbf or less, and specifically may be 1 lbf to 10 lbf, 2 lbf to 7 lbf, or 3 lbf to 5 lbf.

[0062] The above conditioning may include sweeping the polished surface with a brush while applying steam to the polished surface.

[0063] Specifically, the conditioning may include sweeping the polished surface with a brush while applying steam at 80°C to 110°C to the polished surface.

[0064] In this way, when steam is applied to the polished surface while sweeping with a brush during conditioning, the surface recovery can be excellent with less metal contamination compared to when only steam is applied to the polished surface or when only the polished surface is sweeped with a brush.

[0065] The brush used for the above conditioning may have a structure in which bristles are attached to a base made of plastic or metal, and the bristles may be made of fiber or synthetic material. The bristles can condition the surface of the pad by rotating while applying uniform pressure to the polishing surface. The bristles may be arranged in a specific pattern, such as circular, square, or spiral, and this pattern structure can play an important role in optimizing polishing efficiency and the lifespan of the pad.

[0066] The time for sweeping with a brush while applying steam to the polished surface may be, for example, 1 minute or more, 3 minutes or more, or 5 minutes or more, and may also be 3 hours or less, 1 hour or less, 30 minutes or less, 20 minutes or less, 15 minutes or less, or 10 minutes or less; specifically, it may be 1 minute to 3 hours, 1 minute to 1 hour, 1 minute to 30 minutes, 1 minute to 20 minutes, 3 minutes to 20 minutes, or 5 minutes to 15 minutes.

[0067] When sweeping with a brush while applying steam to the above-mentioned polishing surface, the rotational speed of the platen may be, for example, 20 rpm or more, 30 rpm or more, or 40 rpm or more, and may also be 150 rpm or less, 100 rpm or less, or 70 rpm or less, and specifically may be 20 rpm to 150 rpm, or 30 rpm to 100 rpm.

[0068] In addition, the rotational speed of the brush may be, for example, 30 rpm or more, 50 rpm or more, or 70 rpm or more, and may also be 200 rpm or less, 150 rpm or less, or 100 rpm or less, and specifically may be 30 rpm to 200 rpm, 50 rpm to 150 rpm, or 70 rpm to 100 rpm.

[0069] In addition, the load on the abrasive surface of the brush may be, for example, 1 lbf or more, 3 lbf or more, 5 lbf or more, or 7 lbf or more, and may also be 20 lbf or less, 15 lbf or less, or 12 lbf or less, and specifically may be 1 lbf to 20 lbf, 3 lbf to 15 lbf, or 5 lbf to 12 lbf.

[0070] In one embodiment, △Spk according to the following formula may be -1 μm or more, specifically 0 μm or more. More specifically, △Spk according to the following formula may be 1 μm or more. Additionally, △Spk may be 10 μm or less or 5 μm or less. For example, △Spk may be -1 μm to 10 μm, 0 μm to 10 μm, or 1 μm to 10 μm.

[0071] △Spk = Spk2 - Spk1

[0072] Here, Spk1 is the Spk roughness of the polished surface measured after performing the conditioning, and Spk2 is the Spk roughness of the polished surface measured after aging the polished surface after the conditioning and performing the conditioning again, and the aging is polishing five or more wafers having a SiO2 film based on a silica slurry without conditioning under conditions of a platen rotation speed of 93 rpm, a wafer rotation speed of 87 rpm, and a wafer center area reference pressure of 4.1 psi.

[0073]

[0074] In another embodiment, △Sa according to the following formula may be -1 μm or greater, specifically -0.5 μm or greater. Additionally, △Sa may be 5 μm or less or 1 μm or less. More specifically, △Sa may be -1 μm to 5 μm, or -1 μm to 1 μm.

[0075] △Sa = Sa2 - Sa1

[0076] Here, Sa1 is the Sa roughness of the polished surface measured after performing the conditioning, Sa2 is the Sa roughness of the polished surface measured after aging the polished surface after the conditioning and performing the conditioning again, and the aging is polishing five or more wafers having a SiO2 film based on a silica slurry without conditioning under conditions of a platen rotation speed of 93 rpm, a wafer rotation speed of 87 rpm, and a wafer center area reference pressure of 4.1 psi.

[0077] In another embodiment, △Svk according to the following formula may be -1.5 μm or greater, specifically -1 μm or greater. Additionally, △Sa may be 5 μm or less or 1 μm or less. More specifically, △Sa may be -1.5 μm to 5 μm, or -1.5 μm to 1 μm.

[0078] △Svk = Svk2 - Svk1

[0079] Here, Svk1 is the Sa roughness of the polished surface measured after performing the conditioning, and Svk2 is the Sa roughness of the polished surface measured after aging the polished surface after the conditioning and performing the conditioning again, and the aging is polishing five or more wafers having a SiO2 film based on a silica slurry without conditioning under conditions of a platen rotation speed of 93 rpm, a wafer rotation speed of 87 rpm, and a wafer center area reference pressure of 4.1 psi.

[0080] A method for restoring the surface of a polishing pad according to one embodiment may further include a step of cooling the polishing surface after the conditioning step.

[0081]

[0082] Specifically, the surface recovery method of the polishing pad may additionally include a step of cooling the polishing surface after the step of applying steam to the polishing surface, the step of sweeping the polishing surface with a disc while applying steam to the polishing surface, or the step of sweeping the polishing surface with a brush while applying steam to the polishing surface.

[0083] The above cooling step can be performed, for example, by spraying deionized water at or below room temperature onto the polishing surface and rotating the polishing pad.

[0084]

[0085] Polishing pad

[0086]

[0087] A polishing pad according to one embodiment includes a polishing layer comprising a polyurethane resin. In addition, the polishing pad includes a support layer provided below the polishing layer. An adhesive layer may be inserted between the polishing layer and the support layer.

[0088] A polishing pad according to one embodiment includes a polishing layer having a polishing surface.

[0089] In one embodiment, after conditioning the polished surface by applying steam at 95°C for 10 minutes, when the polished surface is analyzed by inductively coupled plasma emission spectrometry (ICP-OES), the increase in titanium (Ti) content after conditioning compared to before conditioning is 100 ppm or less.

[0090] For example, the increase in titanium (Ti) content on the polished surface after the conditioning compared to before the conditioning (i.e., Ti content after conditioning - Ti content before conditioning) may be 100 ppm or less, 50 ppm or less, 30 ppm or less, 20 ppm or less, or 10 ppm or less. Specifically, the increase in titanium (Ti) content on the polished surface after the conditioning compared to before the conditioning may be -50 ppm to 100 ppm, -30 ppm to 100 ppm, -10 ppm to 100 ppm, -30 ppm to 50 ppm, -20 ppm to 50 ppm, -10 ppm to 50 ppm, -20 ppm to 30 ppm, -10 ppm to 30 ppm, or 0 ppm to 30 ppm.

[0091] In another embodiment, when the polished surface is analyzed by inductively coupled plasma emission analysis (ICP-OES), the increase in aluminum (Al) content after conditioning compared to before conditioning may be 10 ppm or less.

[0092] For example, the increase in aluminum (Al) content on the polished surface after the conditioning compared to before the conditioning (i.e., Al content after conditioning - Al content before conditioning) may be 10 ppm or less, 5 ppm or less, 3 ppm or less, 2 ppm or less, or 1 ppm or less. Specifically, the increase in aluminum (Al) content on the polished surface after the conditioning compared to before the conditioning may be -5 ppm to 10 ppm, -3 ppm to 10 ppm, -1 ppm to 10 ppm, -3 ppm to 5 ppm, -2 ppm to 5 ppm, -1 ppm to 5 ppm, -2 ppm to 3 ppm, -1 ppm to 3 ppm, -1 ppm to 2 ppm, -1 ppm to 1 ppm, or 0 ppm to 1 ppm.

[0093] In another embodiment, when the polished surface is analyzed by inductively coupled plasma emission analysis (ICP-OES), the titanium (Ti) content after conditioning is 100 ppm or less. For example, the titanium (Ti) content after conditioning may be 100 ppm or less, 90 ppm or less, 80 ppm or less, 79 ppm or less, 75 ppm or less, or 65 ppm or less, and may also be 0 ppm or more, 30 ppm or more, or 50 ppm or more, and specifically, may be 0 ppm to 100 ppm, 0 ppm to 90 ppm, 0 ppm to 80 ppm, 0 ppm to 79 ppm, or 0 ppm to 75 ppm.

[0094] In another embodiment, when the polished surface is analyzed by inductively coupled plasma emission analysis (ICP-OES), the aluminum (Al) content after conditioning is 10 ppm or less. For example, the aluminum (Al) content after conditioning may be 10 ppm or less, 5 ppm or less, 3 ppm or less, 2 ppm or less, 1.8 ppm or less, or 1.6 ppm or less, and may also be 0 ppm or more, 0.5 ppm or more, or 1 ppm or more, and specifically, may be 0 ppm to 10 ppm, 0 ppm to 5 ppm, 0 ppm to 3 ppm, 0 ppm to 2 ppm, or 0 ppm to 1.8 ppm.

[0095] In another embodiment, when the polished surface is analyzed by inductively coupled plasma emission analysis (ICP-OES), the titanium (Ti) content after conditioning is 100 ppm or less and the aluminum (Al) content is 10 ppm or less.

[0096] In one embodiment, the polishing pad may have a △Spk according to the following formula of -1 μm or more, specifically 0 μm or more. More specifically, the polishing pad may have a △Spk according to the following formula of 1 μm or more. Additionally, △Spk may be 10 μm or less or 5 μm or less. For example, △Spk may be -1 μm to 10 μm, 0 μm to 10 μm, or 1 μm to 10 μm.

[0097] △Spk = Spk2 - Spk1

[0098] Here, Spk1 is the Spk roughness of the polished surface measured after performing the conditioning, and Spk2 is the Spk roughness of the polished surface measured after aging the polished surface after the conditioning and performing the conditioning again, and the aging is polishing five or more wafers having a SiO2 film based on a silica slurry without conditioning under conditions of a platen rotation speed of 93 rpm, a wafer rotation speed of 87 rpm, and a wafer center area reference pressure of 4.1 psi.

[0099] In addition, the polishing pad according to the above embodiment has excellent overall characteristics.

[0100] For example, when polishing the silicon oxide film of the silicon wafer using a ceria slurry on the polishing surface after the conditioning above, the removal rate may be 2500 Å / min or more, 2600 Å / min or more, 2700 Å / min or more, or 2800 Å / min or more, and may also be 3300 Å / min or less, 3200 Å / min or less, 3100 Å / min or less, or 3200 Å / min or less.

[0101] As a specific example, when polishing the silicon oxide film of the silicon wafer using a ceria slurry on the polishing surface after the conditioning, the polishing rate according to the following formula may be 2600 Å / min to 3200 Å / min.

[0102] Polishing rate (RR, Å / min) = Change in film thickness before and after polishing (Å) / Polishing time (min).

[0103] Specifically, the polishing rate may be a polishing rate for a silicon wafer with a diameter of 300 mm on which silicon oxide is deposited. Additionally, the polishing rate may be measured by rotating the platen at 150 rpm for 60 seconds while feeding calcined ceria slurry at 250 mL / min with a polishing load of 4.0 psi and a polishing pad rotation speed of 150 rpm. The temperature conditions for measuring the polishing rate are not particularly limited, but may be, for example, room temperature conditions.

[0104] In addition, the polishing pad according to one embodiment may have a reduction in the polishing rate after the conditioning compared to before (i.e., polishing rate before conditioning - polishing rate after conditioning) of 500 Å / min or less, 300 Å / min or less, 200 Å / min or less, 100 Å / min or less, or 50 Å / min or less. Specifically, the polishing pad may have a reduction in the polishing rate after the conditioning compared to before 0 Å / min to 200 Å / min, 0 Å / min to 100 Å / min, or 0 Å / min to 50 Å / min.

[0105] The thickness of the above abrasive pad may be 0.8 mm to 5.0 mm, 1.0 mm to 4.0 mm, 1.0 mm to 3.0 mm, 1.5 mm to 2.5 mm, 1.7 mm to 2.3 mm, or 2.0 mm to 2.1 mm. Within the above range, the basic physical properties as an abrasive pad can be sufficiently exhibited while minimizing the variation in particle size between the upper and lower parts of the pores.

[0106] Each component of the polishing pad according to one embodiment is described in detail below.

[0107]

[0108] Abrasive layer

[0109] The above polishing layer provides a polishing surface that contacts the semiconductor substrate during the CMP process and constitutes a top pad on the polishing pad.

[0110] It includes a polishing layer comprising a polyurethane resin according to one embodiment.

[0111] The above abrasive layer comprises a urethane-based prepolymer, a foaming agent, and a curing agent. Specifically, the polyurethane resin is obtained from a composition comprising a urethane-based prepolymer, a foaming agent, and a curing agent.

[0112] More specifically, the polishing layer comprises a polyurethane resin, which is a reaction product of a urethane-based prepolymer, a foaming agent, and a curing agent—that is, a cured product of a composition in which the above components are mixed—and accordingly comprises a porous polyurethane resin. Additionally, the polishing layer may comprise a plurality of pores formed from the foaming agent.

[0113] The thickness of the polishing layer may be, for example, 0.8 mm or more, 1 mm or more, 1.2 mm or more, or 1.5 mm or more, and may also be 5 mm or less, 3 mm or less, 2.5 mm or less, or 2 mm or less. As a specific example, the thickness of the polishing layer may be 0.8 mm to 5 mm, or 1.5 mm to 3 mm.

[0114] The specific gravity of the above abrasive layer is, for example, 0.6 g / cm³ 3 Above, 0.7 g / cm³ 3 Above or 0.75 g / cm³ 3 It may be more than 0.9 g / cm³ 3 Below, 0.85 g / cm³ 3 Less than or equal to 0.8 g / cm³ 3 It may be less than or equal to. As a specific example, the specific gravity of the abrasive layer is 0.6 g / cm³ 3 Up to 0.9 g / cm 3 , or 0.7 g / cm³ 3 Up to 0.9 g / cm 3 It could be.

[0115] The hardness of the abrasive layer may, for example, be 30 Shore D or higher, 40 Shore D or higher, or 50 Shore D or higher, and may also be 80 Shore D or lower, 70 Shore D or lower, 65 Shore D or lower, or 60 Shore D or lower. As a specific example, the hardness of the abrasive layer may be 30 Shore D to 80 Shore D, or 50 Shore D to 65 Shore D.

[0116] The tensile strength of the above abrasive layer is, for example, 5 N / mm 2 Above, 10 N / mm 2 ≥15 N / mm 2 It may be more than 30 N / mm 2 Below, 25 N / mm 2 Less than or equal to 20 N / mm 2 It may be less than or equal to. As a specific example, the tensile strength of the abrasive layer is 5 N / mm 2 Up to 30 N / mm 2 , or 15 N / mm 2 Up to 25 N / mm 2 It could be.

[0117] The elongation of the polishing layer may be, for example, 50% or more, 70% or more, 90% or more, 106% or more, or 120% or more, and may also be 300% or less, 250% or less, 200% or less, or 150% or less. As a specific example, the elongation of the polishing layer may be 50% to 300%, or 90% to 130%. The elongation may be the elongation at break.

[0118] As a specific example, the abrasive layer has a hardness of 50 Shore D to 65 Shore D and 15 N / mm 2 Up to 25 N / mm 2 It can have a tensile strength of 90% to 130% and an elongation of 90% to 130%.

[0119] The above pores are dispersed within the polishing layer.

[0120] The average diameter of the above pores may be, for example, 10 µm to 60 µm, 10 µm to 50 µm, 20 µm to 50 µm, 20 µm to 40 µm, 10 µm to 30 µm, 20 µm to 25 µm, or 30 µm to 50 µm.

[0121] In addition, the total area of ​​the pores may be 30% to 60%, 35% to 50%, or 35% to 43% based on the total area of ​​the polishing layer. In addition, the total volume of the pores may be 30% to 70%, or 40% to 60% based on the total volume of the polishing layer.

[0122] The above-mentioned abrasive layer 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.

[0123]

[0124] Urethane-based prepolymer

[0125] A polishing pad according to one embodiment includes a urethane-based prepolymer.

[0126] A prepolymer 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 in the manufacture of cured products. The prepolymer can be formed into a final cured product either on its own or after reacting with other polymerizable compounds.

[0127] In one embodiment, the urethane-based prepolymer can be prepared by reacting an isocyanate compound with a polyol.

[0128] The isocyanate compound used in the manufacture of the above urethane-based prepolymer may be one selected from the group consisting of aromatic diisocyanates, aliphatic diisocyanates, cycloaliphatic diisocyanates, and combinations thereof.

[0129] The above isocyanate compound may include, for example, one selected from the group consisting of toluene 2,4-diisocyanate (2,4-TDI), toluene 2,6-diisocyanate (2,6-TDI), naphthalene 1,5-diisocyanate, para-phenylene diisocyanate, toridine diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and combinations thereof.

[0130] The above polyol is a compound comprising at least two hydroxyl groups (-OH) per molecule, and may include, for example, one selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols, polycaprolactone polyols, and combinations thereof.

[0131] The above polyol may include, for example, one 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, tripropylene glycol, and combinations thereof.

[0132] The above polyol may have a weight-average molecular weight (Mw) of 100 to 3,000. The above polyol may have a weight-average molecular weight (Mw) of, for example, 100 to 3,000, for example, 100 to 2,000, for example, 100 to 1,800.

[0133] In one embodiment, the polyol 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.

[0134]

[0135] The above urethane-based prepolymer may have a weight-average molecular weight (Mw) of 500 to 3,000. The above urethane-based prepolymer may have a weight-average molecular weight (Mw) of, for example, 1,000 to 2,000, or, for example, 1,000 to 1,500.

[0136] In one embodiment, the isocyanate compound for preparing the urethane-based prepolymer may include an aromatic diisocyanate compound, and the aromatic diisocyanate compound may include, for example, 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI). The polyol compound for preparing the urethane-based prepolymer may include polytetramethylene ether glycol (PTMEG) and diethylene glycol (DEG).

[0137] In another embodiment, the isocyanate compound for preparing the urethane-based prepolymer may include an aromatic diisocyanate compound and a cycloaliphatic diisocyanate compound, for example, the aromatic diisocyanate compound may include 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI), and the cycloaliphatic diisocyanate compound may include dicyclohexylmethane diisocyanate (H12MDI). The polyol compound for preparing the urethane-based prepolymer may include polytetramethylene ether glycol (PTMEG) and diethylene glycol (DEG).

[0138] The above urethane-based prepolymer may have an isocyanate end group content (NCO%) of 5 wt% or more, 8 wt% or more, or 10 wt% or more, and may also have 13 wt% or less, 12 wt% or less, or 11 wt% or less. As a specific example, the above urethane-based prepolymer may have an isocyanate end group content (NCO%) of 10 wt% to 11 wt%.

[0139] The isocyanate terminal group content (NCO%) of the above urethane-based prepolymer can be designed by comprehensively controlling the types and content of isocyanate compounds and polyol compounds for manufacturing the above urethane-based prepolymer, process conditions such as temperature, pressure, and time of the process for manufacturing the above urethane-based prepolymer, and the types and content of additives used in manufacturing the above urethane-based prepolymer.

[0140] When the isocyanate terminal group content (NCO%) of the above-mentioned urethane-based prepolymer satisfies the aforementioned range, the reaction rate, reaction time, and final curing structure when subsequently reacting the urethane-based prepolymer with a curing agent can be adjusted in a direction favorable to the polishing performance according to the application and purpose of use of the final polishing pad.

[0141] In one embodiment, the isocyanate end group content (NCO%) of the urethane-based prepolymer may be 8% to 10% by weight, for example, 8% to 9.4% by weight. If the NCO% is below the above range, the desired polishing performance may not be achieved in terms of polishing rate and flatness as electrical characteristics based on the chemical curing structure within the polishing pad, and there may be a problem where the lifespan of the polishing pad is reduced due to an excessive increase in the wear rate, etc. On the other hand, if the NCO% exceeds the above range, surface defects such as scratches and chatter marks on the semiconductor substrate may increase.

[0142]

[0143] blowing agent

[0144] The above foaming agent may include one selected from the group consisting of solid foaming agents, gaseous foaming agents, liquid foaming agents, and combinations thereof as a component for forming a pore structure within the abrasive layer.

[0145] According to one embodiment, the blowing agent may be a non-chlorine blowing agent that does not contain chlorine components, and in particular, may not contain or may minimize the use of chlorine blowing agent components commonly used in the manufacture of polishing pads, such as vinylidene chloride (VDC). For example, the content of the non-chlorine blowing agent based on the total weight of the blowing agent may be 50 wt% or more, 80 wt% or more, 90 wt% or more, 95 wt% or more, 97 wt% or more, 99 wt% or more, or 99.5 wt% or more, and may also be 100 wt% or less or 99.5 wt% or less, and as a specific example, may be 80 wt% to 100 wt%, 90 wt% to 100 wt%, or 80 wt% to 99.5 wt%. In addition, the content of the chlorine-based blowing agent based on the total weight of the blowing agent may be 20% by weight or less, 10% by weight or less, 5% by weight or less, 1% by weight or less, or 0.5% by weight or less, or 0.3% by weight or less, and may also be 0% by weight or more, 0.1% by weight or more, or 0.5% by weight or more, and as a specific example, it may be 0% by weight to 20% by weight, 0% by weight to 1% by weight, 0% by weight to 0.5% by weight, or 0.5% by weight to 20% by weight.

[0146] The above blowing agent may be one or more selected from solid blowing agents containing hollow structure particles, liquid blowing agents using volatile liquids, and inert gases.

[0147] As an example, the solid foaming agent may include hollow particles that are expanded by heat and whose size is controlled. Since such a solid foaming agent is introduced into the raw material in a pre-expanded form and has a uniform particle size, it has the advantage of being able to uniformly control the particle size of the pores.

[0148] In addition, the solid foaming agent may include expandable particles. The expandable particles are particles having the characteristic of being able to expand by heat or pressure, and their size within the final polishing layer may be determined by the heat or pressure applied during the process of manufacturing the polishing layer. The expandable particles may be introduced into the raw material in a pre-extended particle state and may expand due to the heat or pressure applied during the manufacturing process of the polishing layer to determine their final size.

[0149] The average particle size of the solid foaming agent may be, for example, 5 μm to 100 μm, specifically 5 μm to 50 μm, or 20 μm to 50 μm. The average particle size of the solid foaming agent refers to the average particle size of the expanded particles themselves when the solid foaming agent is a particle introduced into the raw material in an expanded state as described below, and may refer to the average particle size of the particles after they have been expanded by heat or pressure during the manufacturing process when the solid foaming agent is a particle introduced into the raw material in an unexpanded state as described below.

[0150] The above-described solid foaming agent of the expandable particle type may include an outer shell made of a resin material; and an expansion-inducing component present inside that is enclosed by said outer shell. These expandable particles may be formed into a hollow structure by vaporizing the internal expansion-inducing component through heat during the manufacturing process.

[0151] For example, the outer shell may include a thermoplastic resin. The thermoplastic resin may be one or more selected from the group consisting of acrylonitrile copolymers, methacrylonitrile copolymers, and acrylic copolymers.

[0152] The thickness of the above outer layer may be, for example, 0.1 μm or more, 0.5 μm or more, 1 μm or more, 2 μm or more, or 3 μm or more, and may also be 15 μm or less, 12 μm or less, or 10 μm or less, and as a specific example, may be 2 μm to 15 μm.

[0153] The above-mentioned swelling-inducing component may include one selected from the group consisting of hydrocarbon compounds, tetraalkylsilane compounds, and combinations thereof. Specifically, the hydrocarbon compound may include one selected from the group consisting of ethane, ethylene, propane, propene, n-butane, isobutene, n-butene, isobutene, n-pentane, isopentane, neopentane, n-hexane, heptane, petroleum ether, and combinations thereof. The above-mentioned tetraalkylsilane compound may include one selected from the group consisting of tetramethylsilane, trimethylethylsilane, trimethylisopropylsilane, trimethyl-n-propylsilane, and combinations thereof.

[0154] The above-mentioned solid blowing agent may include particles treated with an inorganic component. In one embodiment, the surface of the solid blowing agent may be treated with silica (SiO2) particles. The inorganic component treatment of the solid blowing agent can prevent aggregation between multiple particles. The chemical, electrical, and / or physical properties of the surface of the solid blowing agent treated with an inorganic component may differ from those of a solid blowing agent not treated with an inorganic component.

[0155] Commercially available solid foaming agents include Nouryon’s 920DE20d70, 051DET40d25, 051DET40d42, etc., and Matsumoto’s F-65DE, F-80DE, FN-80SDE, etc.

[0156] As a specific example, the foaming agent used in the polishing pad according to the above embodiment includes a solid foaming agent, and the solid foaming agent may include one or more selected from the group consisting of acrylonitrile-based copolymer, methyl methacrylate-based copolymer, methacrylonitrile-based copolymer and acrylic copolymer.

[0157] The content of the solid foaming agent may be 0.1 parts by weight or more, 0.5 parts by weight or more, or 1 part by weight or more based on 100 parts by weight of the urethane-based prepolymer, and may also be 5 parts by weight or less, 3 parts by weight or less, or 2 parts by weight or less. As a specific example, the content of the solid foaming agent may be 0.1 to 5 parts by weight, or 0.5 to 2 parts by weight, based on 100 parts by weight of the urethane-based prepolymer.

[0158] The type and content of the solid foaming agent can be designed according to the desired pore structure and physical properties of the polishing layer.

[0159] Meanwhile, the liquid foaming agent can be introduced during the process in which the prepolymer and curing agent are mixed and reacted to form pores, but it does not participate in the reaction between the prepolymer and the curing agent. Additionally, the liquid foaming agent forms pores by being physically vaporized by the heat generated during the process in which the prepolymer and curing agent are mixed and reacted.

[0160] The above volatile liquid blowing agent does not react with isocyanate groups, amide groups, and alcohol groups, and may be in a liquid state at 25°C. Specifically, the above volatile liquid blowing agent may be selected from the group consisting of cyclopentane, n-pentane, cyclohexane, n-butyl acetate, bis(nonafluorobutyl)(trifluoromethyl)amine; and perfluorocompounds such as perfluorotributylamine, perfluoro-N-methylmorpholine, perfluorotripentylamine, and perfluorohexane. Examples of commercially available perfluoro compounds include FC-40 (3M), FC-43 (3M), FC-70 (3M), FC-72 (3M), FC-770 (3M), FC-3283 (3M), and FC-3284 (3M).

[0161] In addition, the above foaming agent may include a gaseous foaming agent. For example, the above foaming agent may include a solid foaming agent and a gaseous foaming agent.

[0162] The above gaseous blowing agent may include an inert gas. The above gaseous blowing agent may be introduced during the reaction process between the urethane-based prepolymer and the curing agent and used as a pore-forming element.

[0163] The type of the inert gas is not particularly limited as long as it is a gas that does not participate in the reaction between the urethane-based prepolymer and the curing agent. For example, the inert gas may include one selected from the group consisting of nitrogen gas (N2), carbon dioxide gas (CO2), argon gas (Ar), helium gas (He), and combinations thereof.

[0164] The type and content of the gaseous foaming agent can be designed according to the desired pore structure and physical properties of the abrasive layer.

[0165] The above inert gas may be introduced in a volume corresponding to 10% to 30% of the total volume of the composition. Specifically, the above inert gas may be introduced in a volume corresponding to 15% to 30% of the total volume of the composition. Specifically, the above gaseous blowing agent may be injected through a predetermined injection line during the process of mixing the above urethane-based prepolymer, the above solid blowing agent, and the above curing agent. The injection rate of the above gaseous blowing agent may be about 0.8 L / min to about 2.0 L / min, for example, about 0.8 L / min to about 1.8 L / min, for example, about 0.8 L / min to about 1.7 L / min, for example, about 1.0 L / min to about 2.0 L / min, for example, about 1.0 L / min to about 1.8 L / min, for example, about 1.0 L / min to about 1.7 L / min.

[0166]

[0167] hardener

[0168] The curing agent is a compound that chemically reacts with the urethane-based prepolymer to form a final cured structure within the polishing layer, and may include, for example, an amine compound or an alcohol compound. Specifically, the curing agent may include one selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, aliphatic alcohols, and combinations thereof.

[0169] According to one embodiment, the curing agent may include a non-chlorinated curing agent that does not contain a chlorine component. For example, the content of the non-chlorinated curing agent based on the total weight of the curing agent may be 50 wt% or more, 80 wt% or more, 90 wt% or more, 95 wt% or more, 97 wt% or more, 99 wt% or more, or 99.5 wt% or more, and may also be 100 wt% or less or 99.5 wt% or less, and as a specific example, may be 80 wt% to 100 wt%, 90 wt% to 100 wt%, or 80 wt% to 99.5 wt%. In addition, the content of the chlorine-based curing agent based on the total weight of the above curing agent may be 20 wt% or less, 10 wt% or less, 5 wt% or less, 1 wt% or less, or 0.5 wt% or less, or 0.3 wt% or less, and may also be 0 wt% or more, 0.1 wt% or more, or 0.5 wt% or more, and as a specific example, it may be 0 wt% to 20 wt%, 0 wt% to 1 wt%, 0 wt% to 0.5 wt%, or 0.5 wt% to 20 wt%.

[0170] The above curing agent may be at least one selected from solid curing agents and liquid curing agents.

[0171] The above solid-state curing agent may contain active hydrogen groups. The above solid-state curing agent may include amine groups (-NH2) as active hydrogen groups.

[0172] In addition, the solid-state curing agent may be an ester compound having two or more benzene rings. Specifically, the solid-state curing agent may include two or more ester groups within the molecule.

[0173] The weight-average molecular weight of the solid curing agent may be 150 to 400, for example, 150 to 350, for example, 200 to 350, for example, 250 to 350, for example, 300 to 350. The melting point (mp) of the solid curing agent may be 100°C to 150°C, for example, 100°C to 140°C, for example, 110°C to 130°C.

[0174] In one embodiment, the solid curing agent may comprise one or more selected from the group consisting of 1,3-propanediol bis(4-aminobenzoate) (PDPAB), 4-(4-aminobenzoyl)oxyphenyl 4-aminobenzoate, 4-(4-aminobenzoyl)oxybutyl 4-aminobenzoate, 4-[4-(4-aminobenzoyl)oxy-3-methylbutoxy]butyl 4-aminobenzoate, and methylene bis-methylanthranilate (MBNA).

[0175] The above liquid curing agent may contain active hydrogen groups. As active hydrogen groups, the liquid curing agent may include one or more selected from the group consisting of amine groups (-NH2), hydroxyl groups (-OH), carboxylic acid groups (-COOH), epoxy groups, and combinations thereof, and specifically may include amine groups (-NH2).

[0176] In addition, the liquid curing agent may contain sulfur within its molecule, and specifically, may contain two or more sulfur elements within its molecule.

[0177] The above liquid curing agent may have a weight-average molecular weight of 50 to 300, for example, 100 to 250, for example, 150 to 250, or for example, 200 to 250.

[0178] In addition, the liquid curing agent may be liquid at room temperature. Alternatively, the liquid curing agent may have a boiling point (bp) of 160°C to 240°C, specifically 170°C to 240°C, and more specifically 170°C to 220°C.

[0179] Examples of the above liquid curing agents may include one or more selected from the group consisting of 3,5-dimethylthio-2,6-diaminotoluene (DMTDA), 2,6-bis(methylthio)-4-methyl-1,3-benzenediamine, and N,N'-bis(sec-butylamino)diphenylmethane.

[0180] In addition, the curing agent may further include other curing agents in addition to the liquid curing agent and the solid curing agent. The other curing agents may be, for example, one or more of amine compounds and alcohol compounds. Specifically, the other curing agents may include one or more compounds selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols.

[0181] For example, the above other curing agents may be one or more selected from the group consisting of diaminodiphenylmethane, diaminodiphenyl sulfone, m-xylylene diamine, isophoronediamine, ethylenediamine, diethylenetriamine, triethylenetetramine, polypropylenediamine, polypropylenetriamine, ethyleneglycol, diethyleneglycol, dipropyleneglycol, butanediol, hexanediol, glycerin, and trimethylolpropane.

[0182] As a specific example, the curing agent may include one or more selected from the group consisting of diethyltoluenediamine (DETDA), 3,5-dimethylthio-2,6-diaminotoluene (DMTDA), 1,3-propanediol bis(4-aminobenzoate) (PDPAB), N,N'-bis(sec-butylamino)diphenylmethane, 2,6-bis(methylthio)-4-methyl-1,3-benzenediamine, 4-(4-aminobenzoyl)oxyphenyl 4-aminobenzoate, 4-(4-aminobenzoyl)oxybutyl 4-aminobenzoate, 4-[4-(4-aminobenzoyl)oxy-3-methylbutoxy]butyl 4-aminobenzoate, and methylene bis-methylanthranilate (MBNA).

[0183] The content of the curing agent may be 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, or 20 parts by weight or more, based on 100 parts by weight of the urethane-based prepolymer, and may also be 50 parts by weight or less, 45 parts by weight or less, 40 parts by weight or less, 35 parts by weight or less, 30 parts by weight or less, or 25 parts by weight or less. Specifically, the content of the curing agent may be 10 to 40 parts by weight based on 100 parts by weight of the urethane-based prepolymer, and more specifically, 15 to 35 parts by weight, or 15 to 25 parts by weight.

[0184]

[0185] additives

[0186] The composition for manufacturing the above-mentioned polishing layer may further include other additives such as surfactants and reaction rate regulators. The names 'surfactant', 'reaction rate regulator', etc., are arbitrary designations based on the primary role of the respective substances, and each substance does not necessarily perform only the function limited to the role indicated by its name.

[0187] The above surfactant is not particularly limited as long as it is a substance that prevents phenomena such as the aggregation or overlapping of pores. For example, the above surfactant may include a silicone-based surfactant.

[0188] The above surfactant may be used in an amount of 0.2 to 2 parts by weight based on 100 parts by weight of the urethane-based prepolymer. Specifically, the surfactant may be included in an amount of 0.2 to 1.9 parts by weight, for example, 0.2 to 1.8 parts by weight, for example, 0.2 to 1.7 parts by weight, for example, 0.2 to 1.6 parts by weight, for example, 0.2 to 1.5 parts by weight, for example, 0.5 to 1.5 parts by weight, based on 100 parts by weight of the urethane-based prepolymer. When the surfactant is included in an amount within the above range, pores derived from the gas-phase blowing agent can be stably formed and maintained within the mold.

[0189] The above reaction rate regulator acts as a reaction promoter or a reaction retardant, and depending on the purpose, a reaction promoter, a reaction retardant, or both may be used. The above reaction rate regulator may include a reaction promoter. For example, the above reaction promoter may be one or more reaction promoters selected from the group consisting of tertiary amine compounds and organometallic compounds.

[0190] Specifically, the reaction rate regulator is triethylenediamine, dimethylethanolamine, tetramethylbutanediamine, 2-methyl-triethylenediamine, dimethylcyclohexylamine, triethylamine, triisopropanolamine, 1,4-diazabicyclo(2,2,2)octane, bis(2-methylaminoethyl) ether, trimethylaminoethylethanolamine, N,N,N,N,N''-pentamethyldiethylenetriamine, dimethylaminoethylamine, dimethylaminopropylamine, benzyldimethylamine, N-ethylmorpholine, N,N-dimethylaminoethylmorpholine, N,N-dimethylcyclohexylamine, 2-methyl-2-azanobornenein, dibutyltin dilaurate, stannus octoate, dibutyltin diacetate, dioctyltin diacetate, dibutyltin maleate, dibutyltin di-2-ethylhexanoate, and It may include one or more selected from the group consisting of dibutyltin dimercaptide. Specifically, the reaction rate regulator may include one or more selected from the group consisting of benzyldimethylamine, N,N-dimethylcyclohexylamine, and triethylamine.

[0191] The above reaction rate regulator may be used in an amount of 0.05 to 2 parts by weight based on 100 parts by weight of the urethane-based prepolymer. Specifically, the above reaction rate regulator may be used in an amount of 0.05 to 1.8 parts by weight, for example, 0.05 to 1.7 parts by weight, for example, 0.05 to 1.6 parts by weight, for example, 0.1 to 1.5 parts by weight, for example, 0.1 to 0.3 parts by weight, for example, 0.2 to 1.8 parts by weight, for example, 0.2 to 1.7 parts by weight, for example, 0.2 to 1.6 parts by weight, for example, 0.2 to 1.5 parts by weight, for example, 0.5 to 1 part by weight, based on 100 parts by weight of the urethane-based prepolymer. When the above reaction rate regulator is used within the aforementioned content range, the curing reaction rate of the prepolymer composition can be appropriately controlled to form a polishing layer having pores of a desired size and hardness.

[0192]

[0193] Support base

[0194] The above support layer forms a bottom pad and supports the polishing layer while absorbing and dispersing external shocks applied to the polishing layer, thereby minimizing damage and defects to the object to be polished during the polishing process in which the polishing pad is applied.

[0195] The above support layer may include non-woven fabric or suede, but is not limited thereto.

[0196] In one embodiment, the support layer 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.

[0197] 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.

[0198] The thickness of the support layer 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 support layer may be 0.3 mm to 3 mm, or 0.5 mm to 1 mm.

[0199] The hardness of the support layer 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 support layer may be 50 Asker C to 100 Asker C, or 60 Asker C to 90 Asker C.

[0200] In addition, an adhesive layer may be inserted between the polishing layer (upper pad) and the support layer (lower pad).

[0201] 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.

[0202] In addition, double-sided tape can be laminated to the lower part of the support layer, and when applied to CMP equipment, the release liner of the double-sided tape can be removed and attached to the platen for use.

[0203]

[0204] The following embodiments are described, but the scope of implementation is not limited to these.

[0205]

[0206] Preparation Example 1: Preparation of a polishing pad

[0207] Step (1) Preparation of urethane-based prepolymer

[0208] 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%.

[0209] Step (2) Preparation of the polishing layer

[0210] A casting device equipped with tanks and input lines for supplying raw materials such as a prepolymer, a curing agent, an inert gas, and a foaming agent was prepared. The previously manufactured urethane-based prepolymer, curing agent (DMTDA), solid foaming agent (F-65DE, Matsumoto), inert gas (N2), and silicone-based surfactant (Evonik) were filled into their respective tanks. Specifically, 32 parts by weight of curing agent, 1 part by weight of solid foaming agent, and 1 part by weight of surfactant were filled relative to 100 parts by weight of the prepolymer, and the inert gas was introduced at a rate of 1.5 L / min.

[0211] Raw materials were fed into a mixing head at a constant speed through each input line and 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 with a width of 1,000 mm, a length of 1,000 mm, and a height of 3 mm. The temperature of the mold was controlled to approximately 80 (±5)°C. The mixture was solidified within the mold and cast into a sheet. A polishing layer was prepared by post-curing the sheet at approximately 110 (±5)°C for approximately 18 hours.

[0212] Step (3) Manufacturing of the polishing pad

[0213] One side of the abrasive layer was turned using a cutting tool and grooved using a tip to produce an average thickness of 2 mm. A cushion layer impregnated with polyurethane resin was prepared on a polyester fiber nonwoven fabric, and a hot melt adhesive was applied to one side of the cushion layer and the back side of the groove-forming surface of the abrasive layer, respectively. The cushion layer and the abrasive layer were laminated so that the surfaces coated with the respective hot melt adhesives were in contact, and an abrasive pad was manufactured by pressurizing the lamination using a pressure roller under conditions of a temperature of approximately 140 (±5)°C and a pressure of 2 kgf / ㎠.

[0214]

[0215] Experimental Example 1: Conditioning using a diamond disc

[0216] Step (1) Aging

[0217] Five wafers having a SiO2 film based on a silica slurry (Solbrain’s TSO-12) were polished without conditioning under conditions of a platen rotation speed of 93 rpm, a wafer rotation speed of 87 rpm, and a reference pressure of 4.1 psi in the center of the wafer. Polishing was performed for 60 seconds per wafer, and as a result, the surface roughness Spk was reduced to a level of approximately 3 to 5 µm and the surface was aged.

[0218] Step (2) Primary Conditioning

[0219] First, conditioning using a diamond disc was performed for 10 minutes. The diamond disc used was Saesol’s CI45 product, and conditioning was performed with a platen rotation speed of 87 rpm, a diamond disc down force of 9 lbf, and a diamond disc rotation speed of 64 rpm.

[0220] Step (3) Secondary conditioning

[0221] Afterwards, the aging of step (1) and the conditioning of step (2) were repeated, but the conditioning was performed for 3 hours.

[0222]

[0223] Experimental Example 2: Conditioning using steam heating

[0224] Step (1) Aging

[0225] Aging was performed in the same manner as step (1) of Experimental Example 1 above.

[0226] Step (2) Primary Conditioning

[0227] Conditioning using steam heating was performed for 10 minutes. While rotating the platen at a speed of 50 rpm, deionized water (DIW) heated to approximately 90–100°C was sprayed through a nozzle at a flow rate of 200 mL / min for 10 minutes from a height of approximately 3–4 cm above the polishing surface of the polishing pad to perform conditioning, and a silica slurry was supplied to the polishing surface during conditioning. Subsequently, for cooling, the platen was rotated at 100 rpm and room-temperature deionized water was sprayed onto the polishing surface for 1 minute.

[0228]

[0229] Experimental Example 3: Steam heating and conditioning using a diamond disc

[0230] Step (1) Aging

[0231] Aging was performed in the same manner as step (1) of Experimental Example 1 above.

[0232] Step (2) Primary Conditioning

[0233] Conditioning using steam heating was performed for 10 minutes in the same manner as step (2) of Experimental Example 2 above, while conditioning using a diamond disc was performed for 10 minutes. A CI45 diamond disc from Saesol was used, and conditioning was performed with a platen rotation speed of 50 rpm, a diamond disc down force of 9 lbf, and a diamond disc rotation speed of 64 rpm, and silica slurry was supplied to the polishing surface during conditioning. Afterward, for cooling, the platen was rotated at 100 rpm and deionized water at room temperature was sprayed onto the polishing surface for 1 minute.

[0234] Step (3) Secondary conditioning

[0235] Afterwards, the aging of step (1) and the conditioning of step (2) were repeated, but the conditioning was performed for 3 hours.

[0236]

[0237] Experimental Example 4: Conditioning using steam heating and a brush

[0238] Step (1) Aging

[0239] Aging was performed in the same manner as step (1) of Experimental Example 1 above.

[0240] Step (2) Primary Conditioning

[0241] In the same manner as step (2) of Experimental Example 2 above, conditioning using steam heating was performed for 10 minutes, and conditioning using a brush was performed for 10 minutes. A 3M PB36S-K3T MB-01 brush model was used, and conditioning was performed with a brush rotation speed of 87 rpm and a brush load of 3.5 lbf, and silica slurry was supplied to the polishing surface during conditioning. Afterward, to cool, the platen was rotated at 100 rpm and deionized water at room temperature was sprayed onto the polishing surface for 1 minute.

[0242] Step (3) Secondary conditioning

[0243] Afterwards, the aging of step (1) and the conditioning of step (2) were repeated, but the conditioning was performed for 3 hours.

[0244]

[0245] The conditioning conditions of Experimental Examples 1 to 4 are summarized in the table below.

[0246] Classification Experiment Example 1 Experiment Example 2 Experiment Example 3 Experiment Example 4 Conditioning Diamond Disc 10 min Steam Heating 10 min Steam Heating 10 min + Diamond Disc 10 min Steam Heating 10 min + Brush 10 min Platen 87 rpm 50 rpm 50 rpm 50 rpm Disc / Brush Load 9 lbf - 9 lbf 3.5 lbf Steam Flow - 200 mL 200 mL 200 mL Cooling - 100 rpm 1 min 100 rpm 1 min 100 rpm 1 min

[0247] Evaluation example

[0248] The polishing pad was evaluated as follows.

[0249]

[0250] (1) ICP-OES

[0251] - Sample collection: A sample was obtained by perforating the polishing pad into a square of 10 mm x 10 mm size and drying it, and then the lower layer (support layer) and hot melt adhesive were removed to recover only the upper layer (polishing layer).

[0252] - Measurement of Metal Content: The collected samples were placed in an ICP-OES (5110 SVDV, Agilent) and induced into an atomic or ion excited state using argon plasma. The intensity of the emitted light was measured when the electrons of the atoms or ions returned to the ground state or a lower state. Subsequently, the metal content (Ti, Al) in the pyrolysis oil was quantitatively analyzed based on the calibration graph.

[0253]

[0254] (2) Removal rate

[0255] A silicon wafer with a diameter of 300 mm, on which silicon oxide was deposited by a CVD process, was installed in a CMP polishing machine. The silicon wafer was then placed on a platen to which the porous polyurethane polishing pad was attached, with the silicon oxide film facing downward. Subsequently, the silicon oxide film was polished by rotating the platen at 150 rpm for 60 seconds while feeding a silica slurry onto the polishing pad at a rate of 250 mL / min under conditions of a polishing load of 4.0 psi and a polishing pad rotation speed of 150 rpm. After polishing, the silicon wafer was removed from the carrier, mounted on a spin dryer, cleaned with deionized water (DIW), and dried with nitrogen for 15 seconds. The change in film thickness before and after polishing was measured using an optical coherence thickness measuring device (Manufacturer: Keyence, Model: SI-F80R) on the dried silicon wafer. Subsequently, the polishing rate was calculated using the following formula.

[0256] Polishing rate (Å / min) = Change in film thickness before and after polishing (Å) / Polishing time (min)

[0257]

[0258] (3) Defects

[0259] Polishing was performed using CMP polishing equipment in the same manner as the previous polishing rate test. After polishing, the silicon wafer was transferred to a cleaner and cleaned with 1% HF, deionized water (DIW), 1% nitric acid, and deionized water (DIW) for 10 seconds each. Subsequently, it was transferred to a spin dryer, cleaned with deionized water (DIW), and dried with nitrogen for 15 seconds. The changes in defects before and after polishing were measured on the dried silicon wafer using a defect measurement device (Manufacturer: Tenkor, Model: XP+). Specifically, the total number of scratches, chatter marks, pits, and residues on the wafer was measured.

[0260]

[0261] The above test results are shown in Table 2 below. In addition, the results of measuring the oxide film polishing rate according to the conditioning method are shown in Figures 1 and 2, and the oxide film polishing rate profiles are shown in Figures 3 to 6.

[0262] Classification Ti Content (ppm) Al Content (ppm) Polishing Rate After 1st Conditioning (Å / min) Polishing Rate After 2nd Conditioning (Å / min) Number of Defects Before Aging 59.28 1.46 --- After Aging and Before Conditioning 69.34 1.74 --- After Conditioning Experiment 1 79.44 1.82 28 15 26 60 4 Experiment 2 61.26 1.49 29 9 42 9 20 1 Experiment 3 78.64 1.82 29 14 28 13 4 Experiment 4 65.24 1.70 27 8 8 27 20 3

[0263] As shown in the table above, it was confirmed that metal contamination occurs on the surface of the polishing pad depending on the conditioning method, and consequently affects the occurrence of defects.

[0264] In addition, as shown in the table above and Figures 1 to 6, when only a diamond disc was used according to Experimental Example 1, a change in the wafer profile was observed as conditioning was repeated (the polishing rate was low in the center and high in the outer part). Also, when conditioning was performed by steam heating only according to Experimental Example 2, the polishing rate decreased by approximately 12% after the first and second conditioning, but the profile shape remained similar with almost no change. Also, when steam heating and diamond disc conditioning were performed according to Experimental Example 3, the polishing rate decreased by up to approximately 10% after the first and second conditioning, but the profile shape remained similar with almost no change. Furthermore, when steam heating and brush conditioning were performed as in Experimental Example 4, the polishing rate decreased by up to approximately 16% after the first and second conditioning, but the profile shape remained similar with almost no change.

[0265]

[0266] (4) Surface roughness

[0267] Changes in the surface morphology of the polishing pad according to the conditioning method were evaluated.

[0268] The surface roughness of the polishing pad was measured using a 3D scope. The surface roughness of the pad was measured using the destructive and constructive interference phenomena of light. The sample to be measured was placed on the stage aligned with the laser, the lens speed was set, and the position was adjusted so that the focus was placed on the surface of the sample. When the distance was approximately between 5 and 15 mm, the surface of the sample was checked on the monitor, and the surface roughness (Sa, Spk, Svk) was measured.

[0269] The results of the illuminance measurement are shown in Table 3 and Figure 7, and surface images are shown in Figures 8 to 11.

[0270] Classification Sa (㎛) Spk (㎛) Svk (㎛) Experimental Example 1 Aging 9.8 5.6 14.5 1st Conditioning 9.5 11.7 15.1 2nd Conditioning 99.4 16.1 Experimental Example 2 Aging 8.8 5.6 12.6 1st Conditioning 8.6 7.7 13.5 2nd Conditioning 8.3 8.9 14.6 Experimental Example 3 Aging 9.3 5.2 14.3 1st Conditioning 8.9 7.9 14.7 2nd Conditioning 8.7 11.1 13.6 Experimental Example 4 Aging 8.8 5.3 13.9 1st Conditioning 95.7 14.4 2nd Conditioning 8.2 9.9 14.1

[0271] As shown in the table and Figure 7 above, when only a diamond disc was used according to Experimental Example 1, it was confirmed that the roughness peak tended to decrease as conditioning was repeated. In addition, when only steam heating was used according to Experimental Example 2, it was confirmed that the roughness peak tended to increase as conditioning was repeated, and when steam heating and diamond disc conditioning were performed according to Experimental Example 3, it was confirmed that the roughness peak increased after the initial conditioning, and when steam heating and brush conditioning were performed as in Experimental Example 4, the surface did not recover significantly during the initial conditioning process, but the roughness recovered after the second conditioning.

Claims

1. Includes a step of conditioning the polishing surface of the polishing pad, and The above conditioning includes applying steam to the polished surface, and A method for restoring the surface of a polishing pad, wherein, when the polishing surface is analyzed by inductively coupled plasma emission spectrometry (ICP-OES), the increase in titanium (Ti) content after conditioning compared to before conditioning is 100 ppm or less.

2. In Paragraph 1, The above conditioning is A method for restoring the surface of a polishing pad, comprising sweeping the polishing surface with a disc while applying steam at 80°C to 110°C to the polishing surface.

3. In Paragraph 1, The above conditioning is A method for restoring the surface of a polishing pad, comprising sweeping the polishing surface with a brush while applying steam at 80°C to 110°C to the polishing surface.

4. In Paragraph 1, A method for restoring the surface of a polishing pad, wherein, when the polishing surface is analyzed by inductively coupled plasma emission spectrometry (ICP-OES), the increase in aluminum (Al) content after conditioning compared to before conditioning is 10 ppm or less.

5. In Paragraph 1, A surface recovery method for a polishing pad having △Spk of 1 μm or more according to the equation below: △Spk = Spk2 - Spk1 Here Spk1 is the Spk roughness of the polished surface measured after performing the above conditioning, and Spk2 is the Spk roughness of the polished surface measured after aging the polished surface following the conditioning and performing the conditioning again, and The above aging is to polish five or more wafers having a SiO2 film based on a silica slurry without conditioning under conditions of a platen rotation speed of 93 rpm, a wafer rotation speed of 87 rpm, and a wafer center area reference pressure of 4.1 psi.

6. Includes a polishing layer having a polished surface, A polishing pad in which, after conditioning the polishing surface by applying steam at 95°C for 10 minutes, the increase in titanium (Ti) content after conditioning compared to before conditioning is 100 ppm or less when the polishing surface is analyzed by inductively coupled plasma emission spectrometry (ICP-OES).

7. In Paragraph 6, A polishing pad in which, when the polishing surface is analyzed by inductively coupled plasma emission spectrometry (ICP-OES), the increase in aluminum (Al) content after conditioning compared to before conditioning is 10 ppm or less.

8. In Paragraph 6, A polishing pad in which, when the polishing surface is analyzed by inductively coupled plasma emission spectrometry (ICP-OES), the titanium (Ti) content after conditioning is 100 ppm or less and the aluminum (Al) content is 10 ppm or less.

9. In Paragraph 6, A polishing pad having △Spk of 1 μm or more according to the formula below: △Spk = Spk2 - Spk1 Here Spk1 is the Spk roughness of the polished surface measured after performing the above conditioning, and Spk2 is the Spk roughness of the polished surface measured after aging the polished surface following the conditioning and performing the conditioning again, and The above aging is to polish five or more wafers having a SiO2 film based on a silica slurry without conditioning under conditions of a platen rotation speed of 93 rpm, a wafer rotation speed of 87 rpm, and a wafer center area reference pressure of 4.1 psi.

10. In Paragraph 6, A polishing pad having a polishing rate of 2600 Å / min to 3200 Å / min according to the following formula, when polishing a silicon oxide film of a silicon wafer on the polishing surface using a ceria slurry after the above conditioning: Polishing rate (RR, Å / min) = Change in film thickness before and after polishing (Å) / Polishing time (min).

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