Polishing pads and methods for manufacturing semiconductor devices using them

Abstract

According to one embodiment, a polishing pad includes a polishing layer comprising a urethane-based prepolymer and a curing agent, wherein the spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) measured using TD-NMR for the polishing layer satisfy Equations 1 and 2, respectively, and thus can improve the performance of the polishing pad.

Description

Technical Field

[0001] Embodiments of the present invention relate to a polishing pad for a chemical mechanical planarization (CMP) process in semiconductor devices. Background Technology

[0002] In semiconductor fabrication processes, chemical mechanical planarization (CMP) refers to the process of fixing a semiconductor substrate, such as a wafer, to a head and bringing it into contact with the surface of a polishing pad mounted on a platen, and planarizing irregular portions of the semiconductor substrate surface through the relative movement of the platen and the head.

[0003] In this CMP process, the polishing pad needs to have stable physical properties because it has a significant impact on the quality of the semiconductor substrate surface treatment. In particular, since the polishing rate of the CMP process can vary sensitively depending on the composition and physical properties of the polishing pad, it is necessary to optimize the composition and physical properties of the polishing pad.

[0004] In the fabrication of semiconductor devices, the CMP process can be performed multiple times. A semiconductor device comprises multiple layers, each containing complex and intricate circuit patterns. Furthermore, in recent years, the size of individual semiconductor chips has decreased, and the patterns within each layer are becoming increasingly complex and intricate. Therefore, in the fabrication of semiconductor devices, the purpose of the CMP process has expanded beyond simply planarizing circuit wiring; it has also been used for the separation of circuit wiring and the improvement of wiring surfaces. Consequently, more sophisticated and reliable CMP performance is required.

[0005] [Existing Technical Documents]

[0006] (Patent Document 1) Korean Patent Publication No. 2016-0027075. Summary of the Invention

[0007] Technical issues

[0008] The inventors have discovered that when the spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) of the polished layer measured by TD-NMR satisfy a specific relationship, the degree of crosslinking of the polymer is controlled, thereby enhancing the performance of the polishing pad.

[0009] Therefore, the purpose of this implementation is to provide a polishing pad with excellent overall physical properties and performance, while minimizing the occurrence of defects and scratches during the CMP process.

[0010] Solution to the problem

[0011] According to one embodiment, a polishing pad is provided, comprising a polishing layer including a urethane-based prepolymer and a curing agent, wherein the polishing layer satisfies the following relationships 1 and 2.

[0012] [Relationship 1] T1 ≤ 100 ms

[0013] [Relationship 2] T2 ≥ 0.21 ms

[0014] In Equations 1 and 2, T1 is the spin-lattice relaxation time measured by TD-NMR at 25 °C, and T2 is the spin-spin relaxation time measured by TD-NMR at 25 °C.

[0015] According to another embodiment, a method for fabricating a semiconductor device is provided, the method comprising polishing the surface of a semiconductor substrate using a polishing pad.

[0016] Beneficial effects of the invention

[0017] In a polishing pad according to one embodiment, the polishing pad includes a polishing layer comprising a urethane-based prepolymer and a curing agent. The spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) of the polishing layer, measured using TD-NMR, satisfy the relationships 1 and 2 described above, respectively. As a result, the degree of crosslinking of the polymer is controlled, thereby improving the performance of the polishing pad. In the polishing pad according to the embodiment, the spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) are controlled using TD-NMR as described above; therefore, the occurrence of defects and scratches can be minimized during the CMP process while maintaining the excellent overall physical properties and performance of the polishing pad. Attached Figure Description

[0018] Figure 1 The process for manufacturing a semiconductor device according to one embodiment is illustrated schematically.

[0019] (Figure reference numerals - 100: polishing pad, 200: pressure plate, 300: regulator, 400: polishing slurry, 510: polishing head, 520: carrier, 600: semiconductor substrate (wafer)). Detailed Implementation

[0020] Best Implementation of the Invention

[0021] The present invention will now be described in detail with reference to the embodiments. The embodiments are not limited to those disclosed below. Various modifications can be made to the embodiments without altering the essence of the invention.

[0022] In this specification, the terminology used to refer to various components is used to distinguish them from each other and is not intended to limit the scope of the embodiments. Furthermore, in this specification, unless the context otherwise requires, singular expressions are to be interpreted as also encompassing the plural.

[0023] Throughout this specification, when a component is referred to as "containing" an element, it should be understood that, unless otherwise specifically stated, other elements may be included, rather than excluded.

[0024] In this specification, when a component is described as forming above / below another component or being connected or coupled to each other, it covers situations where these components are formed, connected, or coupled directly or indirectly through another component. Furthermore, it should be understood that the criteria for "above" and "below" for each component may vary depending on the orientation of the object being observed.

[0025] Unless otherwise stated, all numerical ranges relating to the physical properties, dimensions, etc. of components used herein should be understood as being modified by the term “approximately”.

[0026] In the numerical ranges of the dimensions, physical properties, etc. of the components described in this specification, when individual examples are limited to the upper limit numerical range and the lower limit numerical range, it should be understood that the numerical range combining these upper and lower limits is also included in the scope of the examples of this invention.

[0027] Polishing pad

[0028] A polishing pad according to one embodiment includes a polishing layer comprising a urethane-based prepolymer and a curing agent, wherein the polishing layer satisfies the following relationships 1 and 2.

[0029] [Relationship 1] T1 ≤ 100 ms

[0030] [Relationship 2] T2 ≥ 0.21 ms

[0031] In Equations 1 and 2, T1 is the spin-lattice relaxation time measured by TD-NMR at 25 °C, and T2 is the spin-spin relaxation time measured by TD-NMR at 25 °C.

[0032] TD-NMR (Time-Domain Nuclear Magnetic Resonance) is a method for analyzing the relaxation time of protons as they absorb energy from a radio frequency (RF) pulse and then release that energy to return to their original state. It can measure the spin-lattice relaxation time (T1), which is the time required for 63% of the z-component of the magnetization M to recover after the application of a resonant pulse, and the spin-spin relaxation time (T2), which is the time required for the xy-plane components of M to change from 100% to 37%.

[0033] Specifically, the polished layer satisfies the following relationships 1 and 2.

[0034] [Relationship 1] T1 ≤ 100 ms

[0035] [Relationship 2] T2 ≥ 0.21 ms

[0036] In Equations 1 and 2, T1 is the spin-lattice relaxation time measured by TD-NMR at 25 °C, and T2 is the spin-spin relaxation time measured by TD-NMR at 25 °C.

[0037] In one implementation, T1 is 100 ms or less. For example, it can be 95 ms or less, 90 ms or less, 85 ms or less, or 80 ms or less, and 0 ms or more, 10 ms or more, 20 ms or more, 30 ms or more, 40 ms or more, 50 ms or more, 60 ms or more, or 70 ms or more, specifically, 0 ms to 100 ms, 0 ms to 95 ms, 0 ms to 90 ms, 0 ms to 85 ms, 10 ms to 100 ms, 20 ms to 100 ms, 30 ms to 100 ms, 40 ms to 100 ms, 50 ms to 100 ms, 60 ms to 100 ms, 10 ms to 95 ms, 20 ms to 95 ms, 30 ms to 95 ms, 40 ms to 95 ms, or 50 ms to 95 ms.

[0038] In one implementation, T2 is 0.21 ms or more. For example, it can be 0.22 ms or more, 0.23 ms or more, 0.24 ms or more, or 0.25 ms or more, and 0.5 ms or less, 0.4 ms or less, 0.3 ms or less, 0.28 ms or less, 0.26 ms or less, 0.25 ms or less, or 0.24 ms or less, specifically, 0.21 ms to 0.5 ms, 0.21 ms to 0.4 ms, 0.21 ms to 0.3 ms, 0.22 ms to 0.5 ms, 0.22 ms to 0.4 ms, 0.22 ms to 0.3 ms, 0.23 ms to 0.5 ms, 0.23 ms to 0.4 ms, or 0.23 ms to 0.3 ms.

[0039] Since T1 and T2 satisfy relations 1 and 2 respectively, the occurrence of defects and scratches can be minimized during the CMP process, while maintaining the excellent overall physical properties and performance of the polishing pad.

[0040] Furthermore, when measured at a deionized water (DIW) supply rate of 150 ml / min under conditions of a platen speed of 90 rpm, a regulator speed of 120 rpm, and a regulator load of 6 psi, the polishing pad can have a pad wear rate (PWR) of 40 μm / 10 min or less.

[0041] For example, the pad wear rate measured under the above conditions can be 40 μm / 10 min or less, 38 μm / 10 min or less, 36 μm / 10 min or less, 35 μm / 10 min or less, 34 μm / 10 min or less, or 33 μm / 10 min or less, and 10 μm / 10 min or more, 20 μm / 10 min or more, 25 μm / 10 min or more, or 30 μm / 10 min or more, specifically, 10 μm / 10 min to 40 μm / 10 min, 20 μm / 10 min to 40 μm / 10 min, or 25 μm / 10 min to 38 μm / 10 min.

[0042] Furthermore, when a polishing pad is used to polish the silicon oxide layer of a silicon wafer with cerium dioxide slurry, the polishing rate (removal rate) according to the following mathematical equation 1 can be from 1,500 Å / min to 6,000 Å / min.

[0043] [Mathematical Equation 1]

[0044] Polishing rate (Å / min) = thickness difference before and after polishing (Å) / polishing time (min)

[0045] For example, when a polishing pad is used to polish the silicon oxide layer of a silicon wafer with cerium dioxide slurry, the polishing rate can be 1,500 Å / min or greater, 1,550 Å / min or greater, 1,600 Å / min or greater, 1,650 Å / min or greater, or 1,700 Å / min or greater, and 6,000 Å / min or less, 4,500 Å / min or less, 3,000 Å / min or less, 2,500 Å / min or less, 2,000 Å / min or less, or 1,900 Å / min or less, specifically, 1,500 Å / min to 4,500 Å / min, 1,550 Å / min to 3,000 Å / min, or 1,600 Å / min to 2,500 Å / min.

[0046] The polishing rate can be, for example, the average polishing rate. Specifically, the silicon oxide layer is polished under a polishing load of 4.0 psi while the platen rotates at 150 rpm for 60 seconds, and calcined cerium dioxide slurry is supplied to the polishing pad at a rate of 250 ml / min. Furthermore, the thickness measurement used to calculate the polishing rate can be performed, for example, by mounting the polished silicon wafer on a rotary dryer, washing it with pure water, drying it with nitrogen for 15 seconds, and then using an optical interferometer on the dried silicon wafer.

[0047] According to one embodiment, the polishing pad includes a polishing layer and a support layer. Furthermore, an adhesive layer may be positioned between the polishing layer and the support layer.

[0048] Each component layer will be described in more detail below.

[0049] Polished layer

[0050] The polishing layer provides a polished surface that contacts the semiconductor substrate during the CMP process and forms the top pad in the polishing pad. During the CMP process, the polishing layer polishes while in contact with the semiconductor substrate.

[0051] In one embodiment, the polishing layer comprises a urethane-based prepolymer and a curing agent. Specifically, the polishing layer comprises a polyurethane-based resin, which is a reaction product of the urethane-based prepolymer and the curing agent, i.e., a cured product of the urethane-based prepolymer.

[0052] In another embodiment, the polishing layer comprises a urethane-based prepolymer, a curing agent, and a foaming agent. Specifically, the polishing layer comprises the reaction product of the urethane-based prepolymer, the curing agent, and the foaming agent, i.e., a porous polyurethane-based resin obtained from a composition of these components.

[0053] The polished layer may include multiple pores formed by a foaming agent.

[0054] Pores are dispersed in the polished layer.

[0055] The average diameter of the pore can 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.

[0056] Furthermore, based on the total area of ​​the polished layer, the total area of ​​the holes can be 30% to 60%, 35% to 50%, or 35% to 43%. Additionally, based on the total volume of the polished layer, the total volume of the holes can be 30% to 70%, or 40% to 60%.

[0057] When analyzed according to the IEC 62321-3-2 standard, the polished layer may have a chlorine (Cl) content of 70,000 ppm or lower. For example, the chlorine (Cl) content of the polishing layer analyzed according to the IEC 62321-3-2 standard can be 65,000 ppm or less, 62,000 ppm or less, or 57,000 ppm or less, and 0 ppm or more, 100 ppm or more, 200 ppm or more, 1,000 ppm or more, 2,500 ppm or more, 5,000 ppm or more, 10,000 ppm or more, or 25,000 ppm or more, specifically, 0 ppm to 70,000 ppm, 100 ppm to 70,000 ppm, 1,000 ppm to 70,000 ppm, 2,500 ppm to 66,000 ppm, 5,000 ppm to 65,000 ppm, 10,000 ppm to 62,000 ppm, 25 ... ppm to 60,000 ppm. When the chlorine (Cl) content in the polishing layer meets the above range, the occurrence of defects and scratches during the CMP process can be minimized, while maintaining the excellent overall physical properties and performance of the polishing pad.

[0058] The polishing pad according to one embodiment may have a fragment particle size of 30 μm or less, 25 μm or less, 20 μm or less, 19 μm or less, 18 μm or less, or 17 μm or less, and 5 μm or more, 10 μm or more, or 15 μm or more.

[0059] Specifically, under conditions of a press speed of 93 rpm, a regulator load of 9 lbs, a regulator speed of 64 rpm, and a scan rate of 19 times / minute, fragmentation may occur during the conditioning process while supplying 300 cc / minute of deionized water. The particle size of the fragments can be the average particle size, i.e., the D50 particle size.

[0060] As a specific example, when the polishing pad is conditioned with deionized water supplied at a rate of 300 cc / min under the conditions of a platen speed of 93 rpm, a regulator load of 9 lbs, a regulator speed of 64 rpm, and 19 scans / min, the resulting polishing pad fragments can have a D50 particle size of 30 µm or less.

[0061] As another specific example, when the polishing pad is conditioned with deionized water supplied at a rate of 300 cc / min under the conditions of a platen speed of 93 rpm, a regulator load of 9 lbs, a regulator speed of 64 rpm, and 19 scans / min, the D50 particle size of the resulting polishing pad fragments can be 10 μm to 30 μm, 10 μm to 25 μm, or 10 μm to 18 μm.

[0062] Furthermore, the polishing pad according to one embodiment can have the ζ potential value of the fragment to be measured within a specific numerical range.

[0063] For example, the zeta potential of an aqueous solution containing fragments obtained by adjusting the concentration of the polishing layer at 0.01% by weight at pH 5.5 can be -20 mV or greater, -10 mV or greater, -5 mV or greater, 0 mV or greater, 5 mV or greater, 7 mV or greater, or 10 mV or greater, and 40 mV or less, 30 mV or less, 20 mV or less, 15 mV or less, 10 mV or less, or 8 mV or less.

[0064] Specifically, the zeta potential of the fragment aqueous solution can be positive (+).

[0065] As a specific example, the zeta potential of an aqueous solution with pH 5.5 containing fragments obtained by adjusting the polishing layer at a concentration of 0.01 wt% can be from -10 mV to 30 mV. As another specific example, the zeta potential of an aqueous solution with pH 5.5 containing fragments obtained by adjusting the polishing layer at a concentration of 0.01 wt% can be from 7 mV to 15 mV. As yet another specific example, the zeta potential of an aqueous solution with pH 5.5 containing fragments obtained by adjusting the polishing layer at a concentration of 0.01 wt% can be from -10 mV to 8 mV.

[0066] Within the aforementioned preferred range, the zeta potential value of the fragments is similar to that of the abrasive particles (e.g., cerium dioxide particles) in the CMP abrasive composition (abrasive slurry), which can further reduce the generation of defects. Specifically, the zeta potential value can quantitatively characterize the magnitude of the interparticle repulsive and attractive forces generated by the positive and negative ions in the suspension; when the zeta potential values ​​of the fragments and the abrasive particles are similar, the interparticle repulsive force increases, thereby preventing particle agglomeration, which can reduce the particle size in the composition and reduce the generation of defects and scratches.

[0067] For example, the hardness of the polished layer can be 30 Shore D or greater, 40 Shore D or greater, 50 Shore D or greater, or 55 Shore D or greater, and 80 Shore D or less, 70 Shore D or less, 65 Shore D or less, or 60 Shore D or less. As a specific example, the hardness of the polished layer can be 50 Shore D to 80 Shore D, 55 Shore D to 80 Shore D, 50 Shore D to 65 Shore D, 55 Shore D to 70 Shore D, or 55 Shore D to 65 Shore D. The Shore D hardness can be determined, for example, by cutting the polished layer into pieces 2 mm thick, 5 cm wide, and 5 cm long, storing them at 25°C for 12 hours, and measuring them using a hardness tester.

[0068] The polished layer can have, for example, 5 N / mm 2 Or larger, 10 N / mm 2 Or larger, or 15 N / mm 2 or larger, and 30 N / mm 2 or smaller, 25 N / mm 2 Or smaller, or 20 N / mm 2 Or even lower tensile strength. As a specific example, the tensile strength of the polished layer could be 5 N / mm. 2 Up to 30 N / mm 2 Or 15 N / mm 2 Up to 25 N / mm 2 Tensile strength can be measured, for example, by cutting the polished layer into pieces 2 mm thick, 1 cm wide, and 4 cm long, and performing a tensile test using a universal testing machine (UTM) at a speed of 50 mm / min.

[0069] For example, the elongation of the polished layer can be 50% or greater, 70% or greater, 90% or greater, 106% or greater, or 120% or greater, and can be 300% or less, 250% or less, 200% or less, or 150% or less. As a specific example, the elongation of the polished layer can be from 50% to 300% or from 90% to 150%. The elongation can be the elongation at break. For example, the maximum deformation length before fracture can be measured by cutting the polished layer into pieces with a thickness of 2 mm, a width of 1 cm, and a length of 4 cm, and performing a tensile test using a universal testing machine (UTM) at a speed of 50 mm / min, and obtaining the percentage (%) of the maximum deformation length to the initial length, which is the elongation.

[0070] According to a specific example, the hardness of the polished layer can be from 55 Shore D to 70 Shore D, the tensile strength can be from 15 N / mm² to 25 N / mm², and the elongation can be from 90% to 150%.

[0071] The polished layer may have grooves on its surface for mechanical polishing. The grooves may have the depth, width, and spacing required for mechanical polishing, without particular limitations.

[0072] According to one embodiment, the polishing pad contains a urethane-based prepolymer.

[0073] Prepolymers typically refer to polymers with relatively low molecular weights, where the degree of polymerization is tuned to an intermediate level to facilitate product molding during the manufacturing process. Prepolymers can be molded alone or after reacting with another polymerizable compound. For example, prepolymers can be prepared by reacting isocyanate compounds with polyols.

[0074] The isocyanate compound used to prepare urethane-based prepolymers can be selected from the group consisting of aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, or combinations thereof.

[0075] For example, isocyanate compounds may include 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, p-phenylene diisocyanate, bimethyl diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and combinations thereof.

[0076] A polyol is a compound containing at least two or more hydroxyl groups (-OH) per molecule. For example, it can contain one selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols, polycaprolactone polyols, and combinations thereof.

[0077] For example, polyols may include one selected from the group consisting of polytetramethylene ether glycol, polypropylene glycol ether glycol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 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.

[0078] Polyols can have a weight-average molecular weight (Mw) of 100 g / mol to 3,000 g / mol. For example, the weight-average molecular weight of polyols can be 100 g / mol to 3,000 g / mol, 100 g / mol to 2,000 g / mol, or 100 g / mol to 1,800 g / mol.

[0079] According to one embodiment, the polyol may include low molecular weight polyols with a weight average molecular weight (Mw) of 100 g / mol to 300 g / mol and high molecular weight polyols with a weight average molecular weight (Mw) of 300 g / mol to 1,800 g / mol.

[0080] Furthermore, the urethane-based prepolymer can have a weight-average molecular weight (Mw) of 500 g / mol to 3,000 g / mol. For example, the weight-average molecular weight of the urethane-based prepolymer can be 500 g / mol to 2,500 g / mol, 1,000 g / mol to 2,000 g / mol, or 1,000 g / mol to 1,500 g / mol.

[0081] According to one embodiment, the isocyanate compound used to prepare the urethane-based prepolymer may include an aromatic diisocyanate compound, and the aromatic diisocyanate compound may, for example, include 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI). The polyol compound used to prepare the urethane-based prepolymer may include polytetramethylene ether glycol (PTMEG) and diethylene glycol (DEG).

[0082] According to another embodiment, the isocyanate compound used to prepare the urethane-based prepolymer may include aromatic diisocyanate compounds and alicyclic diisocyanate compounds. For example, aromatic diisocyanate compounds include 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI), and alicyclic diisocyanate compounds include dicyclohexylmethane diisocyanate (H12MDI). The polyol compound used to prepare the urethane-based prepolymer may include polytetramethylene ether glycol (PTMEG) and diethylene glycol (DEG).

[0083] The isocyanate end-group content (NCO%) of urethane-based prepolymers can be 5% by weight or higher, 8% by weight or higher, 9% by weight or higher, or 10% by weight or higher, and 15% by weight or lower, 13% by weight or lower, 12% by weight or lower, or 11% by weight or lower. For example, urethane-based prepolymers can have an isocyanate end-group content (NCO%) of 5% to 15% by weight. As a specific example, urethane-based prepolymers can have an isocyanate end-group content (NCO%) of 8% to 15% by weight, 9% to 15% by weight, 8% to 11% by weight, or 9% to 10% by weight.

[0084] The isocyanate end group content (NCO%) of urethane-based prepolymers can be designed by comprehensively adjusting the type and content of isocyanate and polyol compounds used in the preparation of urethane-based prepolymers, the process conditions such as temperature, pressure and time in the preparation of urethane-based prepolymers, and the type and content of additives used in the preparation of urethane-based prepolymers.

[0085] If the isocyanate end group content (NCO%) of the urethane-based prepolymer meets the above range, then from the perspective of the final polishing pad's use and purpose, the reaction rate, reaction time, and final cured structure in the subsequent reaction between the urethane-based prepolymer and the curing agent can be adjusted in a way that is beneficial to polishing performance.

[0086] According to one embodiment, the urethane-based prepolymer may have an isocyanate end group content (NCO%) of 9% to 15% by weight.

[0087] Within the preferred range of isocyanate end-group content (NCO%) described above, T1 and T2 can be controlled by adjusting physical properties such as the degree of crosslinking of the polymer constituting the polishing layer. As a result, CMP performance can be optimized, and quality can be uniformly controlled.

[0088] If the NCO% of the urethane-based prepolymer is less than the above range, electrical properties based on the chemically hardened structure in the polishing pad can be achieved, making it impossible to achieve the desired polishing performance in terms of polishing rate and smoothness, and potentially shortening the polishing pad life due to excessive increase in pad cutting rate. On the other hand, if the NCO% exceeds the above range, surface defects on the semiconductor substrate, such as scratches and grooves, will increase.

[0089] A curing agent is a compound used to chemically react with a urethane-based prepolymer to form a final cured structure in the polished layer. For example, it may contain amine compounds or alcohol compounds. Specifically, the curing agent may include one selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, aliphatic alcohols, and combinations thereof.

[0090] According to one embodiment, the curing agent may include a non-chlorine-based curing agent that does not contain chlorine components. For example, based on the total weight of the curing agent, the content of the non-chlorine-based curing agent may be 50% by weight or higher, 80% by weight or higher, 90% by weight or higher, 95% by weight or higher, 97% by weight or higher, 99% by weight or higher, or 99.5% by weight or higher, and 100% by weight or lower or 99.5% by weight or lower. As a specific example, it may be 80% to 100% by weight, 90% to 100% by weight, or 80% to 99.5% by weight. Furthermore, based on the total weight of the curing agent, the content of the chlorine-based curing agent can be 20% by weight or less, 10% by weight or less, 5% by weight or less, 1% by weight or less, 0.5% by weight or less, or 0.3% by weight or less, as well as 0% by weight or more, 0.1% by weight or more, 0.5% by weight or more, and as a specific example, 0% to 20% by weight, 0% to 1% by weight, 0% to 0.5% by weight, or 0.5% to 20% by weight.

[0091] The curing agent can be at least one selected from solid-phase curing agents and liquid-phase curing agents.

[0092] Solid-phase curing agents can contain active hydrogen groups. Solid-phase curing agents can contain amine groups (-NH2) as active hydrogen groups.

[0093] Furthermore, the solid-phase curing agent can be an ester compound containing two or more benzene rings. Specifically, the solid-phase curing agent can contain two or more ester groups in its molecule.

[0094] For example, solid-phase curing agents can have a weight-average molecular weight of 150 g / mol to 400 g / mol, 150 g / mol to 350 g / mol, 200 g / mol to 350 g / mol, 250 g / mol to 350 g / mol, or 300 g / mol to 350 g / mol. Furthermore, solid-phase curing agents can have a melting point (mp) of 100°C to 150°C, 100°C to 140°C, or 110°C to 130°C.

[0095] In one embodiment, the solid curing agent comprises at least one selected from the group consisting of 1,3-propanediol bis(4-aminobenzoate) (PDPAB), 4-(4-aminobenzoyl)oxyphenyl-4-aminobenzoate, 4-(4-aminobenzoyl)4-aminobenzoate oxybutyl ester, 4-[4-(4-aminobenzoyl)oxy-3-methylbutoxy]butyl 4-aminobenzoate and methylene bis-methyl o-aminobenzoate (MBNA).

[0096] Liquid-phase curing agents may contain active hydrogen groups. Specifically, they may contain at least one active hydrogen group selected from the group consisting of amine (-NH2), hydroxyl (-OH), carboxylic acid (-COOH), epoxy group, and combinations thereof.

[0097] Furthermore, the molecules of liquid phase curing agents can contain sulfur. Specifically, they can contain two or more sulfur elements in their molecules.

[0098] Liquid phase curing agents can have a weight-average molecular weight of 50 to 300, for example 100 to 250, for example 150 to 250, for example 200 to 250.

[0099] Furthermore, the liquid phase curing agent can be a liquid at room temperature. Alternatively, the liquid phase curing agent can 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.

[0100] Examples of liquid phase curing agents include at least one selected from the group consisting of 3,5-dimethylthio-2,6-diaminotoluene (DMTDA), 2,6-bis(methylthio)-4-methyl-1,3-phenylenediamine, and N,N'-bis(sec-butylamino)diphenylmethane.

[0101] In addition to liquid-phase curing agents and solid-phase curing agents, curing agents may also contain other curing agents. Additional curing agents may be at least one of, for example, amine compounds and alcohol compounds. Specifically, additional curing agents may contain a compound selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols.

[0102] For example, the additional curing agent may be at least one selected from the group consisting of diaminodiphenylmethane, diaminodiphenyl sulfone, m-phenylenediamine, isophorone diamine, ethylenediamine, diethylenetriamine, triethylenetetramine, polypropylenediamine, polypropylenetriamine, ethylene glycol, diethylene glycol, dipropylene glycol, butanediol, hexanediol, glycerol, and trimethylolpropane.

[0103] As a specific example, the curing agent may include at least one selected from the group consisting of 4,4'-methylenebis(2-chloroaniline) (MOCA), 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-phenylenediamine, 4-(4-aminobenzoyl)oxyphenyl-4-aminobenzoate, 4-(4-aminobenzoyl)4-aminobenzoate oxybutyl ester, 4-[4-(4-aminobenzoyl)oxy-3-methylbutoxy]butyl 4-aminobenzoate and methylenebis-methyl-o-aminobenzoate (MBNA).

[0104] The curing agent content may be 60 parts by weight or more relative to 100 parts by weight of the urethane-based prepolymer. For example, the curing agent content may be 62 parts by weight or more, 65 parts by weight or more, or 70 parts by weight or more, and 100 parts by weight or less, 95 parts by weight or less, 90 parts by weight or less, 85 parts by weight or less, 80 parts by weight or less, or 75 parts by weight or less, specifically, 62 to 100 parts by weight or 65 to 90 parts by weight.

[0105] Within the aforementioned preferred content range of the curing agent, T1 and T2 can be controlled by adjusting physical properties such as the degree of crosslinking of the polymer constituting the polishing layer. As a result, CMP performance can be optimized, and quality can be uniformly controlled.

[0106] Furthermore, the equivalent ratio of urethane-based prepolymer to curing agent can be from 1:0.5 to 2. For example, the equivalent ratio of urethane-based prepolymer to curing agent can be from 1:0.5 to 1.5, 1:0.5 to 1.0, or 1:0.6 to 1.2.

[0107] A foaming agent is a component used to form a porous structure in a polished layer. It may include one selected from the group consisting of solid-phase foaming agents, gas-phase foaming agents, liquid-phase foaming agents, and combinations thereof.

[0108] According to one embodiment, the blowing agent can be a non-chlorinated blowing agent that does not contain chlorine. Specifically, it can exclude or minimize the use of chlorinated blowing agent components commonly used in the preparation of polishing pads, such as vinylidene chloride (VDC). For example, based on the total weight of the blowing agent, the content of the non-chlorinated blowing agent can be 50% by weight or higher, 80% by weight or higher, 90% by weight or higher, 95% by weight or higher, 97% by weight or higher, 99% by weight or higher, or 99.5% by weight or higher, and 100% by weight or lower or 99.5% by weight or lower. As a specific example, it could be 80% to 100% by weight, 90% to 100% by weight, or 80% to 99.5% by weight. Furthermore, based on the total weight of the foaming agent, the content of the chlorine-based foaming agent can be 20% by weight or less, 10% by weight or less, 5% by weight or less, 1% by weight or less, 0.5% by weight or less, or 0.3% by weight or less, as well as 0% by weight or more, 0.1% by weight or more, 0.5% by weight or more, and as a specific example, 0% to 20% by weight, 0% to 1% by weight, 0% to 0.5% by weight, or 0.5% to 20% by weight.

[0109] The foaming agent may be selected from at least one of solid-phase foaming agents including particles with a hollow structure, liquid-phase foaming agents using volatile liquids, and inert gases.

[0110] As an example, a solid-phase foaming agent may comprise particles with a hollow structure that have been expanded and sized by heating. This type of solid-phase foaming agent has the advantage of controlling the pore size to be uniform because it is used in the raw material in an expanded form and has a uniform particle size.

[0111] Furthermore, the solid-phase foaming agent may include expandable particles. These expandable particles are particles that can expand through heat or pressure. Their size in the final polished layer can be determined by the heat or pressure applied during the preparation of the polished layer. The expandable particles are used in the raw material in their unexpanded particle state. Their final size is determined by the expansion caused by the heat or pressure applied during the preparation of the polished layer.

[0112] Solid-phase foaming agents can have an average particle size of 5 μm to 100 μm, specifically 5 μm to 50 μm or 20 μm to 50 μm. When the solid-phase foaming agent is used in particles of a raw material in an expanded state as described below, the average particle size of the solid-phase foaming agent can refer to the average particle size of the expanded particles themselves. When the solid-phase foaming agent is used in particles of a raw material in an unexpanded state as described below, it can refer to the average particle size of the particles after thermal or pressure expansion during the preparation process.

[0113] Solid-phase foaming agents in the form of expandable particles can comprise a resin shell and an expansion-inducing component encapsulated within the shell. These expandable particles can form a hollow structure by evaporating the encapsulated expansion-inducing component through heating during the preparation process.

[0114] For example, the housing may include a thermoplastic resin. The thermoplastic resin may be at least one selected from the group consisting of acrylonitrile copolymers, methacrylonitrile copolymers, and acrylic copolymers.

[0115] The thickness of the shell can be, for example, 0.1 μm or greater, 0.5 μm or greater, 1 μm or greater, 2 μm or greater, or 3 μm or greater, and 15 μm or less, 12 μm or less, or 10 μm or less, as a specific example, 2 μm to 15 μm.

[0116] The swelling-inducing component may include one selected from the group consisting of hydrocarbon compounds, tetraalkylsilane compounds, and combinations thereof. Specifically, the hydrocarbon may include one selected from the group consisting of ethane, ethylene, propane, propylene, n-butane, isobutane, n-butene, isobutene, n-pentane, isopentane, neopentane, n-hexane, heptane, petroleum ether, and combinations thereof. The tetraalkylsilane compound may include one selected from the group consisting of tetramethylsilane, trimethylethylsilane, trimethylisopropylsilane, trimethyln-propylsilane, and combinations thereof.

[0117] Solid-phase foaming agents may include particles treated with inorganic components. In one embodiment, the solid-phase foaming agent may be a foaming agent treated with silica (SiO2) particles. Treating the solid-phase foaming agent with inorganic components can prevent aggregation between multiple particles. Solid-phase foaming agents treated with inorganic components may differ from those not treated with inorganic components in terms of the chemical, electrical, and / or physical properties of the foaming agent surface.

[0118] Commercial solid-phase foaming agents include Nouryon's 920DE20d70, 051DET40d25 and 051DET40d42, and Matsumoto's F-65DE, F-80DE and FN-80SDE.

[0119] As a specific example, the foaming agent used in a polishing pad according to one embodiment includes a solid-phase foaming agent. The solid-phase foaming agent may include at least one selected from the group consisting of acrylonitrile-based copolymers, methyl methacrylate-based copolymers, methacrylonitrile-based copolymers, and acrylic copolymers.

[0120] The content of the solid blowing agent relative to 100 parts by weight of the urethane-based prepolymer can be 0.1 parts by weight or more, 0.5 parts by weight or more, or 1 part by weight or more, and 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 blowing agent relative to 100 parts by weight of the urethane-based prepolymer can be from 0.1 parts by weight to 5 parts by weight or from 0.5 parts by weight to 2 parts by weight.

[0121] In one embodiment, the polishing layer comprises a foaming agent, wherein the foaming agent comprises at least one selected from the group consisting of acrylonitrile-based copolymers, methyl methacrylate-based copolymers, methacrylonitrile-based copolymers, and acrylic copolymers. The content of the foaming agent may be from 0.1 parts by weight to 5 parts by weight relative to 100 parts by weight of urethane-based prepolymer.

[0122] The type and content of solid foaming agent can be designed according to the required pore structure and physical properties of the polished layer.

[0123] Simultaneously, the liquid-phase foaming agent can be introduced during the mixing and reaction of the prepolymer and curing agent to form pores. It does not participate in the reaction between the prepolymer and curing agent. Furthermore, the liquid-phase foaming agent is formed by the thermophysical evaporation generated during the mixing and reaction of the prepolymer and curing agent.

[0124] Volatile liquid-phase blowing agents are liquid at 25°C and do not react with isocyanate groups, amide groups, or alcohol groups. Specifically, volatile liquid-phase blowing agents can be selected from cyclopentane, n-pentane, cyclohexane, n-butyl acetate, bis(nonafluorobutyl)(trifluoromethyl)amine; and perfluorinated compounds, such as perfluorotributylamine, perfluoro-N-methylmorpholine, perfluorotributylamine, and perfluorohexane. Commercially available perfluorinated compounds include FC-40 (3M), FC-43 (3M), FC-70 (3M), FC-72 (3M), FC-770 (3M), FC-3283 (3M), and FC-3284 (3M).

[0125] In addition, foaming agents can include gas-phase foaming agents. For example, foaming agents can include solid-phase foaming agents and gas-phase foaming agents.

[0126] Vapor-phase foaming agents may include inert gases. The vapor-phase foaming agent is added during the reaction of the urethane-based prepolymer and the curing agent to serve as a pore-forming component.

[0127] There are no particular restrictions on the type of inert gas, 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 (N2), carbon dioxide (CO2), argon (Ar), helium (He), and combinations thereof.

[0128] The type and content of the vapor phase foaming agent can be designed according to the required pore structure and physical properties of the polished layer.

[0129] The inert gas can be fed at a volume of 10% to 30% based on the total volume of the composition. Specifically, the inert gas can be fed at a volume of 15% to 30% based on the total volume of the composition. Specifically, the fumed gas can be fed through a predetermined feed pipe while the urethane-based prepolymer, solid-phase blowing agent, and curing agent are mixed. For example, the feed rate of the fumed gas is about 0.8 L / min to about 2.0 L / min, about 0.8 L / min to about 1.8 L / min, about 0.8 L / min to about 1.7 L / min, about 1.0 L / min to about 2.0 L / min, about 1.0 L / min to about 1.8 L / min, or about 1.0 L / min to about 1.7 L / min.

[0130] The composition used to prepare the polished layer may further contain other additives, such as surfactants and reaction rate controllers. Names such as "surfactant" and "reaction rate controller" are arbitrary names based on the primary function of the substance. The corresponding substance does not necessarily perform only the function defined by its name.

[0131] There are no particular limitations on surfactants, as long as they prevent pores from coalescing and overlapping. For example, surfactants can include silicone-based surfactants.

[0132] The amount of surfactant can be from 0.2 parts by weight to 2 parts by weight relative to 100 parts by weight of urethane-based prepolymer. Specifically, the surfactant can be used in amounts of 0.2 parts by weight to 1.9 parts by weight, 0.2 parts by weight to 1.8 parts by weight, 0.2 parts by weight to 1.7 parts by weight, 0.2 parts by weight to 1.6 parts by weight, 0.2 parts by weight to 1.5 parts by weight, or 0.5 parts by weight to 1.5 parts by weight relative to 100 parts by weight of urethane-based prepolymer. If the amount of surfactant is within the above range, pores originating from the vapor-phase blowing agent can be stably formed and maintained in the mold.

[0133] Reaction rate controllers are used to promote or retard reactions. Depending on the purpose, reaction promoters, reaction inhibitors, or both can be used. Reaction rate controllers may contain reaction promoters. For example, a reaction rate controller may be at least one reaction promoter selected from the group consisting of tertiary amine compounds and organometallic compounds.

[0134] Specifically, the reaction rate control agent may comprise at least one selected from the group consisting of triethylenediamine, dimethylethanolamine, tetramethylbutyldiamine, 2-methyltriethylenediamine, dimethylcyclohexylamine, triethylamine, triisopropanolamine, 1,4-diazabicyclo[2,2,2]octane, bis(2-methylaminoethyl) ether, trimethylaminoethylethanolamine, N,N,N,N,N''-pentamethyldiethyldimethylaminoethylamine, dimethylaminopropylamine, benzyldimethylamine, N-ethylmorpholine, N,N-dimethylaminoethylmorpholine, N,N-dimethylcyclohexylamine, 2-methyl-2-azanorbornene, dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, dioctyltin diacetate, dibutyltin maleate, dibutyltin bis-2-ethylhexanoate, and dibutyltin dithiol. Specifically, the reaction rate control agent may include at least one selected from the group consisting of benzyldimethylamine, N,N-dimethylcyclohexylamine and triethylamine.

[0135] The amount of reaction rate control agent relative to 100 parts by weight of urethane-based prepolymer can be from 0.05 parts by weight to 2 parts by weight. Specifically, relative to 100 parts by weight of urethane-based prepolymer, the reaction rate control agent can be used at amounts of 0.05 parts by weight to 1.8 parts by weight, 0.05 parts by weight to 1.7 parts by weight, 0.05 parts by weight to 1.6 parts by weight, 0.1 parts by weight to 1.5 parts by weight, 0.1 parts by weight to 0.3 parts by weight, 0.2 parts by weight to 1.8 parts by weight, 0.2 parts by weight to 1.7 parts by weight, 0.2 parts by weight to 1.6 parts by weight, 0.2 parts by weight to 1.5 parts by weight, or 0.5 parts by weight to 1 part by weight. If the reaction rate control agent is used within the above-mentioned content range, the curing reaction rate of the prepolymer composition can be appropriately controlled to form a polished layer with pores of the desired size and hardness.

[0136] The thickness of the polishing layer can 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 these ranges, the basic physical properties of the polishing pad can be fully exhibited, while minimizing the particle size variation between the upper and lower portions.

[0137] support layer

[0138] The support layer forms the bottom pad, which supports the polishing layer and absorbs and disperses the impact applied to it. Therefore, during the polishing process using the polishing pad, it minimizes damage and defects to the object being polished.

[0139] The support layer may include, but is not limited to, nonwoven fabric or suede.

[0140] In one embodiment, the support layer may be a resin-impregnated nonwoven fabric. The nonwoven fabric may be a fibrous nonwoven fabric, including one selected from the group consisting of polyester fibers, polyamide fibers, polypropylene fibers, polyethylene fibers, and combinations thereof.

[0141] The resin impregnated in the nonwoven fabric may include 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.

[0142] The thickness of the support layer can be 0.3 mm or greater, or 0.5 mm or greater, or 3 mm or less, 2 mm or less, or 1 mm or less. As a specific example, the thickness of the support layer can be from 0.3 mm to 3 mm or from 0.5 mm to 1 mm.

[0143] The hardness of the support layer can be 50 Asker C or greater, 60 Asker C or greater, or 70 Asker C or greater, and 100 Asker C or less, 90 Asker C or less, or 80 Asker C or less. As a specific example, the hardness of the support layer can be 50 Asker C to 100 Asker C or 60 Asker C to 90 Asker C.

[0144] In addition, the adhesive layer can be located between the polishing layer (top pad) and the support layer (bottom pad).

[0145] The adhesive layer may include a hot melt adhesive. Specifically, the hot melt adhesive may contain at least one selected from the group consisting of polyurethane resins, polyester resins, ethylene-vinyl acetate resins, polyamide resins, and polyolefin resins. Specifically, the hot melt adhesive may be at least one selected from the group consisting of polyurethane resins and polyester resins.

[0146] In addition, double-sided tape can be laminated under the support layer. When it is applied to CMP equipment, it is attached to the pressure plate for use once the release paper of the double-sided tape is removed.

[0147] Method for preparing polishing pads

[0148] A method for preparing a polishing pad according to one embodiment includes preparing a composition for the polishing pad, said composition comprising a urethane-based prepolymer, a foaming agent, and a curing agent; injecting the composition for the polishing pad into a mold and curing it to prepare a polishing layer; and laminating the polishing layer with a support layer.

[0149] The specific types and contents of urethane-based prepolymers, curing agents, and foaming agents are as described above.

[0150] As a specific example, the foaming agent includes a solid-phase foaming agent, which includes at least one selected from the group consisting of acrylonitrile-based copolymers, methyl methacrylate-based copolymers, methacrylonitrile-based copolymers, and acrylic copolymers, and the curing agent includes at least one 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-phenylenediamine, 4-(4-aminobenzoyl)oxyphenyl-4-aminobenzoate, 4-(4-aminobenzoyl)4-aminobenzoate oxybutyl ester, 4-[4-(4-aminobenzoyl)oxy-3-methylbutoxy]butyl 4-aminobenzoate, and methylene bis-methyl-o-aminobenzoate (MBNA).

[0151] The composition of the polishing pad can be prepared by sequentially or simultaneously mixing a urethane-based prepolymer, a foaming agent, and a curing agent.

[0152] As an example, the steps for preparing the composition of the polishing pad can be performed by mixing a urethane-based prepolymer with a curing agent and then further mixing it with a foaming agent, or by mixing a urethane-based prepolymer with a foaming agent and then further mixing it with a curing agent.

[0153] As another example, urethane-based prepolymers, curing agents, and foaming agents can be added to the mixing process substantially simultaneously. If foaming agents, surfactants, and inert gases are further added, they can also be added to the mixing process substantially simultaneously.

[0154] As another example, urethane-based prepolymers, foaming agents, and surfactants can be premixed, followed by the introduction of a curing agent or a curing agent with an inert gas.

[0155] Mixing initiates the reaction between the urethane-based prepolymer and the curing agent, while uniformly dispersing the foaming agent and inert gas in the raw materials. In this case, a reaction rate control agent can intervene in the reaction between the urethane-based prepolymer and the curing agent from the beginning of the reaction, thereby controlling the reaction rate. Specifically, mixing can be carried out at speeds of 1,000 to 10,000 rpm or 4,000 to 7,000 rpm. Within these speed ranges, uniform dispersion of the inert gas and foaming agent in the raw materials may be more advantageous.

[0156] Furthermore, the steps for preparing the polishing pad composition can be carried out at temperatures ranging from 50°C to 150°C. If necessary, it can be carried out under vacuum defoaming conditions.

[0157] If the foaming agent includes a solid-phase foaming agent, the step of preparing the composition of the polishing pad may include mixing a urethane-based prepolymer and a solid-phase foaming agent to prepare a first preliminary composition; and mixing the first preliminary composition and a curing agent to prepare a second preliminary composition.

[0158] The viscosity of the first preliminary composition at about 80°C may be about 1,000 cps to about 2,000 cps, for example about 1,000 cps to about 1,800 cps, for example about 1,000 cps to about 1,600 cps, for example about 1,000 cps to about 1,500 cps.

[0159] If the foaming agent includes a fumed foaming agent, the steps of preparing the composition for the polishing pad may include preparing a third preliminary composition comprising a urethane-based prepolymer and a curing agent; and feeding a fumed foaming agent into the third preliminary composition to prepare a fourth preliminary composition. In one embodiment, the third preliminary composition may further comprise a solid-phase foaming agent.

[0160] In one embodiment, the step of preparing the polishing layer includes preparing a mold preheated to a first temperature; injecting a composition for the polishing pad into the preheated mold and curing it; and post-curing the curing composition for the polishing pad at a second temperature above the preheated temperature.

[0161] In one embodiment, the temperature difference between the first temperature and the second temperature can be from about 10°C to about 40°C, for example, from about 10°C to about 35°C, or from about 15°C to about 35°C. In one embodiment, the first temperature can be from about 60°C to about 100°C, for example, from about 65°C to 95°C, or from about 70°C to 90°C. In one embodiment, the second temperature can be from about 100°C to about 130°C, for example, from about 100°C to about 125°C, or from about 100°C to about 120°C.

[0162] The step of curing the composition of the polishing pad at the first temperature can be carried out for about 5 minutes to about 60 minutes, for example, about 5 minutes to about 40 minutes, for example, about 5 minutes to about 30 minutes, for example, about 5 minutes to about 25 minutes.

[0163] The post-curing step of the polishing pad composition cured at a first temperature and a second temperature can be carried out for about 5 hours to about 30 hours, for example, about 5 hours to about 25 hours, for example, about 10 hours to about 30 hours, for example, about 10 hours to about 25 hours, for example, about 12 hours to about 24 hours, for example, about 15 hours to about 24 hours.

[0164] Subsequently, the step of injecting the polishing pad composition into the mold and allowing it to cure can be carried out at a temperature of 60°C to 120°C and a pressure of 50 kg / m³. 2 Up to 200kg / m 2 It is carried out under pressure conditions.

[0165] Furthermore, the above-described manufacturing process may further include steps such as cutting the surface of the resulting polishing pad, machining grooves on its surface, attaching it to the substrate, inspection, and packaging. These steps can be performed using conventional methods for manufacturing polishing pads.

[0166] As an example, the method of preparing a polishing pad may further include processing at least one side of the polishing layer. The step of processing at least one side of the polishing layer may include forming a groove on at least one side of the polishing layer; turning at least one side of the polishing layer on a lathe; and roughening at least one side of the polishing layer.

[0167] The grooves may include at least one concentric circular groove spaced apart from the center of the polished layer; and radial grooves continuously connected from the center of the polished layer to its edge. Lathe turning can be performed by cutting the polished layer to a certain thickness using a cutting tool. Roughening can be performed by machining the surface of the polished layer with a sanding roller.

[0168] Methods for fabricating semiconductor devices

[0169] A method for fabricating a semiconductor device according to another embodiment includes polishing the surface of a semiconductor substrate using a polishing pad.

[0170] Specifically, a method for fabricating a semiconductor device may include providing a polishing pad according to one embodiment; and a polishing surface of a polishing layer and a surface of a semiconductor substrate that are rotated relative to each other while they are in contact with each other to polish the surface of the semiconductor substrate.

[0171] Figure 1 A method for fabricating a semiconductor device using a polishing pad according to one embodiment is illustrated. (Reference) Figure 1 Once the polishing pad (100) according to one embodiment has been attached to the pressure plate (200), the semiconductor substrate (600), which is the object to be polished, is placed on the polishing pad (100). In this case, the surface of the semiconductor substrate (600) to be polished is in direct contact with the polishing surface of the polishing pad (100). Polishing slurry (400) can be sprayed onto the polishing pad through a nozzle for polishing. The flow rate of the polishing slurry (400) supplied through the nozzle can be approximately 10 cm depending on the desired effect. 3 / minute to approximately 1,000 cm 3 Choose within a range of / minute. For example, it could be approximately 50 cm. 3 / minute to approximately 500 cm 3 / minute, but not limited to this.

[0172] Subsequently, the semiconductor substrate (600) and the polishing pad (100) rotate relative to each other, thereby polishing the surface of the semiconductor substrate (600). In this case, the rotation direction of the semiconductor substrate (600) and the rotation direction of the polishing pad (100) can be the same or opposite. The rotation speed of the semiconductor substrate (600) and the polishing pad (100) can be selected in the range of about 10 rpm to about 500 rpm, depending on the purpose. For example, it can be about 30 rpm to about 200 rpm, but is not limited thereto.

[0173] A semiconductor substrate (600) mounted on a polishing head (510) is pressed against the polishing surface of a polishing pad (100) with a predetermined load to make contact with it, and its surface can then be polished. The load applied by the polishing head (510) to the polishing surface of the polishing pad (100) through the surface of the semiconductor substrate (600) can be approximately 1 gf / cm, depending on the purpose. 2 Approximately 1,000 gf / cm 2 Choose within the range. For example, it could be approximately 10 gf / cm³. 2 Approximately 800 gf / cm 2 However, it is not limited to this.

[0174] In one embodiment, the semiconductor substrate (600), serving as the object to be polished, may include an oxide layer, a tungsten layer, or a composite layer thereof. Specifically, the semiconductor substrate (600) may include an oxide layer, a tungsten layer, or a composite layer of oxide and tungsten layers. The composite layer of oxide and tungsten layers may be a multilayer film, wherein the tungsten layer is laminated on one side of the oxide layer, or it may be a monolayer film, wherein oxide regions and tungsten regions are mixed in a monolayer. Because the object to be polished has this film material, and the polishing pad simultaneously has the characteristics according to this embodiment, the semiconductor device manufactured according to the method for fabricating a semiconductor device can have minimal defects.

[0175] In one embodiment, the process for fabricating a semiconductor device may further include, in the step of polishing the object to be polished, providing either a slurry for polishing an oxide layer or a slurry for polishing a tungsten layer; or sequentially supplying a slurry for polishing an oxide layer and a slurry for polishing a tungsten layer to the polishing surface.

[0176] For example, if the semiconductor substrate, which is the object to be polished, includes an oxide layer, the method of fabricating a semiconductor device may include providing a slurry for polishing the oxide layer. If the semiconductor substrate includes a tungsten layer, the method of fabricating a semiconductor device may include providing a slurry for polishing the tungsten layer. If the semiconductor substrate includes a composite layer of oxide and tungsten layers, the method of fabricating a semiconductor device may include sequentially supplying slurries for polishing the oxide layer and for polishing the tungsten layer to the polishing surface. Here, depending on the process, the slurry for polishing the oxide layer may be supplied first, followed by the slurry for polishing the tungsten layer, or the slurry for polishing the tungsten layer may be supplied first, followed by the slurry for polishing the oxide layer.

[0177] In one embodiment, in order to maintain the polished surface of the polishing pad (100) in a state suitable for polishing, the method for fabricating a semiconductor device may further include processing the polished surface of the polishing pad (100) with a conditioner (300) while polishing the semiconductor substrate (600).

[0178] In the polishing pad according to the implementation scheme, TD-NMR is used to control the spin-lattice relaxation time (T1) and spin-spin relaxation time (T2); therefore, the occurrence of defects and scratches can be minimized during the CMP process while maintaining the excellent overall physical properties and performance of the polishing pad.

[0179] Embodiments of the present invention

[0180] The above description will be explained in detail below through the following embodiments. However, the scope of the embodiments is not limited to the following embodiments.

[0181] Example 1: Preparation of polishing pad

[0182] (1) Preparation of urethane-based prepolymers

[0183] Toluene diisocyanate (TDI), dicyclohexylmethane diisocyanate (H12MDI), polytetramethylene ether glycol (PTMEG), and diethylene glycol (DEG) were loaded into a four-necked flask and reacted at 80°C for 3 hours to prepare an urethane-based prepolymer with an isocyanate end group content (NCO%) of 10%.

[0184] (2) Preparation of polishing pad

[0185] A casting machine is provided, equipped with tanks and feed lines for raw materials such as urethane-based prepolymers, curing agents, and inert gases. Specifically, the urethane-based prepolymer prepared in step (1), the curing agent (4,4'-methylenebis(2-chloroaniline), MOCA), the solid-phase foaming agent (average particle size: 20 µm), the inert gas (N2), and the siloxane surfactant (manufacturer: Evonik) are each loaded into tanks. In this case, 70 parts by weight of the curing agent, 5 parts by weight of the surfactant, and 5 parts by weight of the solid-phase foaming agent are added to 100 parts by weight of the urethane-based prepolymer, and the inert gas is supplied at a rate of 2 L / min.

[0186] Subsequently, the raw materials are stirred while being fed into the mixing head at a constant rate through their respective feed pipes (mixing head speed: approximately 5,000 rpm). A mold (1,000 mm × 1,000 mm × 3 mm) is prepared and preheated to 80°C. The stirred mixture is poured into the mold and reacted to obtain a molded article in the form of a solid cake. The top and bottom of the molded article are then ground to obtain a polished layer for a top pad.

[0187] Subsequently, the polishing layer undergoes surface grinding and groove formation steps, and is laminated with a support layer for the bottom pad using a hot melt adhesive to prepare the polishing pad. In this case, double-sided adhesive tape (442JS, 3M) is laminated under the support layer so that it can be attached to the pressure plate of the CMP equipment.

[0188] Examples 2 to 6: Preparation of polishing pads

[0189] The polishing pad was prepared in the same manner as in Example 1, except that the components and contents were changed as shown in Table 1 below.

[0190] Comparative Examples 1 to 6: Preparation of Polishing Pads

[0191] The polishing pad was prepared in the same manner as in Example 1, except that the components and contents were changed as shown in Table 2 below.

[0192] [Table 1]

[0193] [Table 2]

[0194] Test Example 1: Hardness

[0195] The hardness of the polished layers of Examples 1 to 6 and Comparative Examples 1 to 6 was measured. Specifically, each polished layer was cut into pieces 2 mm thick, 5 cm long, and 5 cm wide, and stored at 25°C for 12 hours. Its Shore D hardness was measured using a hardness tester.

[0196] Test Example 2: Elongation

[0197] The elongation of the polished layers in Examples 1 to 6 and Comparative Examples 1 to 6 was measured. Specifically, each polished layer was cut into pieces 2 mm thick, 4 cm long, and 1 cm wide, and the maximum deformation length before fracture was measured in a tensile test using a universal testing machine (UTM) at a speed of 50 mm / min. The ratio of the maximum deformation length to the initial length was then obtained as a percentage (%).

[0198] Test Example 3: TD-NMR

[0199] The spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) of the polished layers of Examples 1 to 6 and Comparative Examples 1 to 6 were measured using TD-NMR.

[0200] Specifically, each polishing layer of 10 g is cut into 3 mm pieces. 2 The slides were prepared, and T1 and T2 were measured using TD-NMR (product name: mini-spec, manufacturer: Bruker) at room temperature (25°C). In this case, T1 and T2 were calculated as the time required to recover to 63% of the original equilibrium state.

[0201] Test Example 4: Chlorine (Cl) Content

[0202] The chlorine content of the polished layers of Examples 1 to 6 and Comparative Examples 1 to 6 was measured. Specifically, circular samples with a diameter of 3 cm and a height of 0.3 cm were prepared from each polished layer. The chlorine content in the samples was measured according to IEC 62321-3-2, which is the international standard for measuring specific substances in polymers by combustion ion chromatography (C-IC).

[0203] Test Example 5: Polishing Rate (Removal Rate)

[0204] The polishing pads of Examples 1 to 6 and Comparative Examples 1 to 6 were each fixed to the pressure plate of the CMP equipment, and a silicon wafer (300 mm in diameter) was placed with its silicon oxide layer facing down. Then, the CMP process was performed to measure the polishing rate.

[0205] Specifically, the silicon oxide layer was polished under a polishing load of 4.0 psi, while the platen rotated at 150 rpm for 60 seconds, and calcined cerium dioxide slurry was supplied to the polishing pad at a rate of 250 ml / min. After polishing, the silicon wafer was removed from the carrier, placed in a rotary dryer, rinsed with deionized water, and then dried with nitrogen for 15 seconds. The thickness difference of the silicon oxide layer in the dried silicon wafer before and after polishing was measured using a spectroreflectometer-type thickness gauge (model: SI-F80R, manufacturer: Keyence). The polishing rate was calculated according to the following mathematical equation 1.

[0206] [Mathematical Equation 1]

[0207] Polishing rate (Å / min) = thickness difference before and after polishing (Å) / polishing time (min)

[0208] Test Example 6: Pad Wear Rate

[0209] The pad wear rate (PWR) of the polishing pads in Examples 1 to 6 and Comparative Examples 1 to 6 was measured. Each polishing pad was mounted on the pressure plate of a CMP device, and deionized water (DIW) was supplied at a rate of 150 ml / min under the conditions of a pressure plate speed of 90 rpm, a regulator speed of 120 rpm, and a regulator load of 6 psi, while the change in polishing layer thickness was measured for 10 minutes.

[0210] [Table 3]

[0211] [Table 4]

[0212] As can be seen from Tables 1 and 2 above, the polishing pads of Examples 1 to 6 respectively meet the requirements of T1 of 100 ms or less and T2 of 0.21 ms or more, and the chlorine content, polishing rate, PWR and other physical properties of the polishing pads are all within the expected range.

Claims

1. A polishing pad comprising a polishing layer, said polishing layer comprising a urethane-based prepolymer and a curing agent, wherein said polishing layer satisfies the following relationships 1 and 2: [Relation 1] T1 ≤ 100 ms [Relationship 2] T2 ≥ 0.21 ms In Equations 1 and 2, T1 is the spin-lattice relaxation time measured by TD-NMR at 25 °C, and T2 is the spin-spin relaxation time measured by TD-NMR at 25 °C.

2. The polishing pad according to claim 1, wherein the polishing pad has a pad wear rate (PWR) of 40 μm / 10 min or less when measured at a deionized water (DIW) supply rate of 150 ml / min under conditions of a platen speed of 90 rpm, a regulator speed of 120 rpm and a regulator load of 6 psi.

3. The polishing pad according to claim 1, wherein the polishing layer has a chlorine (Cl) content of 70,000 ppm or less when analyzed according to IEC 62321-3-2 standard.

4. The polishing pad according to claim 1, wherein when the polishing pad is used to polish the silicon oxide layer of a silicon wafer having a cerium dioxide slurry, the polishing rate is from 1,500 Å / min to 6,000 Å / min according to the following mathematical equation 1: [Mathematical Equation 1] Polishing rate (Å / min) = thickness difference before and after polishing (Å) / polishing time (min).

5. The polishing pad according to claim 1, wherein the content of the curing agent is 60 parts by weight or more relative to 100 parts by weight of urethane-based prepolymer.

6. The polishing pad according to claim 1, wherein the curing agent comprises at least one selected from the group consisting of 4,4'-methylenebis(2-chloroaniline) (MOCA), 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-phenylenediamine, 4-(4-aminobenzoyl)oxyphenyl-4-aminobenzoate, 4-(4-aminobenzoyl)4-aminobenzoate oxybutyl ester, 4-[4-(4-aminobenzoyl)oxy-3-methylbutoxy]butyl 4-aminobenzoate and methylenebis-methyl-o-aminobenzoate (MBNA).

7. The polishing pad according to claim 1, wherein the urethane-based prepolymer has an isocyanate end group content (NCO%) of 5% to 15% by weight.

8. The polishing pad according to claim 1, wherein, The polishing layer contains a foaming agent. The foaming agent comprises at least one selected from the group consisting of acrylonitrile copolymers, methyl methacrylate copolymers, methacrylonitrile copolymers, and acrylic copolymers. The content of the foaming agent is from 0.1 parts by weight to 5 parts by weight relative to 100 parts by weight of urethane-based prepolymer.

9. The polishing pad according to claim 1, wherein, The polished layer has a hardness of 55 Shore D to 70 Shore D, a tensile strength of 15 N / mm² to 25 N / mm², and an elongation of 90% to 150%.

10. A method for fabricating a semiconductor device, comprising polishing the surface of a semiconductor substrate using a polishing pad according to claim 1.

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