A polishing liquid for 14-nanometer cmp process, and a preparation method and application thereof

Abstract

This invention discloses a polishing slurry for 14nm CMP processes, its preparation method, and its application. The slurry's components have been optimized for 14nm CMP processes. It is formulated with abrasive particles, a nonionic copolymer dispersant, a pH buffer, an organic acid, a pH adjuster, a surfactant, a viscosity modifier, a corrosion inhibitor, an oxidant, a first additive, and a second additive. The nonionic copolymer dispersant is an EO / PO block copolymer. The first additive comprises 3-sulfopropyltetradecyl dimethyl betaine and 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane in a mass ratio of (5~10):1. This slurry offers advantages such as high polishing speed, high polishing uniformity, and few polishing defects in CMP processes. Furthermore, the polishing selectivity can be adjusted by regulating the proportions of each component in the slurry, making it suitable for polishing different types of substrates.

Description

Technical Field

[0001] This invention relates to the field of chemical mechanical polishing (CMP) technology, and more specifically, to a polishing slurry for a 14-nanometer CMP process, its preparation method, and its application. Background Technology

[0002] As the physical substrate of integrated circuits, the thickness uniformity, surface smoothness, and contamination-free state of wafers are core prerequisites for ensuring the precision of subsequent processes, device performance, and yield. Currently, rough grinding of wafer surfaces is mainly accomplished through specialized grinding processes; while achieving nanometer-level planarization of wafer surfaces is primarily achieved through chemical mechanical polishing (CMP). CMP is a core process in semiconductor manufacturing for achieving ultra-precision wafer planarization. It utilizes the synergistic effect of chemical etching and mechanical polishing—the softening reaction of the wafer surface material by chemical reagents in the polishing slurry, combined with the mechanical abrasive force of abrasive grains and polishing pads—to precisely remove excess material from the surface. This process relies on core elements such as polishing machines, polishing slurries, and polishing pads, and is widely used in key processes such as silicon wafer fabrication and dielectric and metal interconnect layers. Ultimately, it enables wafers to achieve sub-nanometer roughness, nanometer-level global flatness, and uniform thickness, providing a flat substrate for subsequent high-precision processes such as photolithography.

[0003] In recent years, CMP (Chemical Motion Processing) has been widely used for polishing silicon oxide films, silicon nitride films, polycrystalline silicon films, and metal films in semiconductor devices. By adjusting the proportions of various components in the polishing slurry, selective polishing of these film materials can be achieved. In CMP, the choice of abrasive grains has a significant impact on the subsequent polishing effect. If abrasive grains with high hardness and large particle size are selected, scratches and pits are easily caused on the wafer surface during the process, increasing the wafer defect rate. Conversely, if abrasive grains with low hardness and small particle size are selected, the polishing speed is greatly reduced, decreasing the efficiency of wafer processing.

[0004] Especially in Cu interconnects and ILD (interlayer dielectric) CMP processes using 14nm technology, polishing slurries face multiple challenges due to the reduction in feature size and the application of new materials: In Cu interconnect CMP, the selectivity ratio of Cu to the barrier layer and ILD needs to be precisely balanced to avoid pitting or residue, while also addressing sensitivity issues such as chemical corrosion and mechanical scratches; issues such as oxidant decomposition and particle agglomeration need to be avoided to prevent insufficient stability of polishing rate; ILD CMP materials, due to the fragility of low-k or ULK (ultra-low dielectric constant) materials, face compatibility challenges such as easy chemical erosion and mechanical peeling, and the process also needs to balance planarization efficiency and surface roughness, while preventing the polishing slurry from etching the underlying metal (such as Cu) or dielectric layer to ensure the integrity of the interconnect structure.

[0005] Therefore, developing a CMP slurry with high grinding speed, low grinding unevenness, adjustable grinding selectivity, and few grinding defects remains an urgent problem to be solved. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned defects in the prior art and provide a polishing slurry for 14nm CMP process, its preparation method and application. The components of the polishing slurry have been optimized and designed specifically for 14nm CMP process. It is formulated with abrasive particles, nonionic copolymer dispersant, pH buffer, organic acid, pH adjuster, surfactant, viscosity modifier, corrosion inhibitor, oxidant, first additive and second additive. The nonionic copolymer dispersant is EO / PO block copolymer. The first additive includes 3-sulfopropyltetradecyl dimethyl betaine and 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane in a mass ratio of (5~10):1. It has the advantages of high polishing speed, high polishing uniformity and few polishing defects in CMP process. Moreover, the polishing selectivity can be controlled by adjusting the proportion of each component in the polishing slurry, which can be adapted to polishing different types of substrates.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] This invention discloses a polishing slurry for a 14nm CMP process, comprising the following components by weight percentage: 0.1wt%~10wt% abrasive particles, 0.001wt%~0.5wt% nonionic copolymer dispersant, 0.01wt%~1wt% pH buffer, 10wt%~20wt% organic acid, 0.01wt%~1wt% pH adjuster, 0.01wt%~1wt% surfactant, 0.1wt%~1wt% viscosity modifier, and 0. The composition includes 0.1 wt% to 0.1 wt% corrosion inhibitor, 0.5 wt% to 5 wt% oxidant, 0.5 wt% to 2 wt% first additive, 0.5 wt% to 2 wt% second additive, and the balance being ultrapure water; the nonionic copolymer dispersant is an EO / PO block copolymer; the first additive comprises 3-sulfopropyltetradecyl dimethyl betaine and 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane in a mass ratio of (5~10):1.

[0009] This invention also discloses a method for preparing the polishing slurry for a 14nm CMP process as described above, comprising the following steps:

[0010] The grinding fluid is obtained by mixing abrasive particles, nonionic copolymer dispersant, pH buffer, organic acid, pH adjuster, surfactant, viscosity modifier, corrosion inhibitor, oxidant, first additive, second additive and ultrapure water.

[0011] The present invention also discloses a polishing slurry for a 14-nanometer CMP process as described above, or the application of a polishing slurry prepared by the preparation method described above in a 14-nanometer CMP process.

[0012] Implementing the embodiments of the present invention will have the following beneficial effects:

[0013] Compared with existing CMP polishing slurries, this invention has the advantages of high polishing speed, low polishing non-uniformity, adjustable polishing selectivity, and fewer polishing defects. Furthermore, this invention provides a polishing slurry for 14nm CMP processes. Through optimized component selection, it is specifically designed for 14nm CMP processes and employs a compound of abrasive particles, a nonionic copolymer dispersant, a pH buffer, organic acid, pH adjuster, surfactant, viscosity modifier, corrosion inhibitor, oxidant, a first additive, and a second additive. The nonionic copolymer dispersant is an EO / PO block copolymer, which increases surface hydrophilicity and promotes uniform spreading of the polishing slurry, thereby improving its polishing uniformity. It also maintains physical stability by reducing water absorption and swelling of the polishing pad, promoting uniform distribution of the polishing slurry and accelerating chip removal. The process improves grinding uniformity by adding 3-sulfopropyltetradecyl dimethyl betaine and 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane in a specific mass ratio. 3-sulfopropyltetradecyl dimethyl betaine, due to its zwitterionic properties, ensures high dispersion stability of the abrasive particles and adsorbs onto the metal surface to form a corrosion-inhibiting film. 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane, through its organic base properties and weak complexing ability, synergistically works with the corrosion inhibitor to improve overall corrosion inhibition efficiency. The two work together in a specific ratio to achieve high polishing rate, high selectivity, and low surface defects.

[0014] The system of this invention ensures high dispersion stability of abrasive particles, thereby guaranteeing the uniformity of the polishing slurry system. It enhances the oxidation of the inorganic oxide film, which is beneficial for polishing, and precisely treats the metallic Cu layer through the synergistic effect of the oxidant and corrosion inhibitor. This achieves high polishing performance while minimizing defects such as scratches. Furthermore, by adjusting the proportions of various components in the polishing slurry, it can meet the requirements of different Cu / TaN polishing selectivity ratios. Detailed Implementation

[0015] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention in any way.

[0016] This invention discloses a polishing slurry for a 14nm CMP process, comprising the following components by weight percentage: 0.1wt%~10wt% abrasive particles, 0.001wt%~0.5wt% nonionic copolymer dispersant, 0.01wt%~1wt% pH buffer, 10wt%~20wt% organic acid, 0.01wt%~1wt% pH adjuster, 0.01wt%~1wt% surfactant, 0.1wt%~1wt% viscosity modifier, 0.01wt%~0.1wt% corrosion inhibitor, 0.5wt%~5wt% oxidant, 0.5wt%~2wt% first additive, 0.5wt%~2wt% second additive, and the balance being ultrapure water.

[0017] Furthermore, the nonionic copolymer dispersant is an EO / PO block copolymer.

[0018] Furthermore, the first additive comprises 3-sulfopropyltetradecyl dimethyl betaine and 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane in a mass ratio of (5~10):1.

[0019] In one specific embodiment, the polishing slurry for the 14nm CMP process comprises the following components by weight percentage: 0.1wt%~5wt% abrasive particles, 0.005wt%~0.2wt% nonionic copolymer dispersant, 0.01wt%~0.05wt% pH buffer, 10wt%~20wt% organic acid, 0.01wt%~1wt% pH adjuster, 0.01wt%~1wt% surfactant, 0.1wt%~1wt% viscosity modifier, 0.01wt%~0.1wt% corrosion inhibitor, 0.5wt%~5wt% oxidant, 0.5wt%~2wt% first additive, 0.5wt%~2wt% second additive, and the balance being ultrapure water.

[0020] In one specific embodiment, the polishing slurry for the 14nm CMP process comprises the following components by weight percentage: 1wt%~2wt% abrasive particles, 0.01wt%~0.02wt% nonionic copolymer dispersant, 0.01wt%~0.03wt% pH buffer, 10wt%~20wt% organic acid, 0.01wt%~1wt% pH adjuster, 0.01wt%~1wt% surfactant, 0.1wt%~1wt% viscosity modifier, 0.01wt%~0.1wt% corrosion inhibitor, 0.5wt%~5wt% oxidant, 0.5wt%~2wt% first additive, 0.5wt%~2wt% second additive, and the balance being ultrapure water.

[0021] Specifically, this invention controls the polishing slurry for the 14nm CMP process to include abrasive particles at a weight percentage of 0.1wt% to 10wt%. When the content is less than 0.1wt%, the polishing speed and uniformity will decrease; when it exceeds 10wt%, defects such as scratches may occur due to over-polishing. Furthermore, as the number of abrasive particles increases, the number of abrasive particles remaining on the wafer surface also increases. The adhesion of these residual abrasive particles may cause other defects such as particle contamination and surface adsorption residues. This invention controls the weight percentage of nonionic copolymer dispersant in the polishing slurry to be 0.001wt% to 0.5wt%, which can further ensure polishing speed and polishing uniformity. This invention controls the weight percentage of pH buffer in the polishing slurry to be 0.01wt% to 1wt%. When the content of pH buffer is less than 0.01wt%, the dispersion stability of abrasive particles is improved. The pH buffer content will decrease; when the content exceeds 1 wt%, the excessive pH buffer will accelerate coagulation and cause precipitation, which will reduce the dispersion stability and grinding uniformity, resulting in defects on the surface of the polished film; the present invention controls the weight percentage of organic acid in the polishing slurry to be 10 wt%~20 wt%. When the organic acid content is less than 10 wt%, the polishing performance will decrease; when the organic acid content exceeds 20 wt%, it will lead to an increase in surface defects on the substrate; the pH adjuster adjusts the dispersibility of the coated abrasive by adjusting the pH of the polishing slurry. The present invention controls the pH adjuster content in the polishing slurry to be 0.01 wt%~1 wt%. When the pH adjuster content exceeds 1 wt%, the excessive pH adjuster will accelerate coagulation and cause precipitation, which will reduce the dispersion stability of the abrasive, make the polished film prone to defects, and also reduce the grinding uniformity.

[0022] In one specific embodiment, the abrasive particles are selected from at least one of metal or silicon oxide, metal or silicon oxide having an organic coating or an inorganic coating, colloidal metal or silicon oxide, and modified colloidal metal or silicon oxide.

[0023] In one specific embodiment, the shape of the abrasive grains is selected from at least one of spherical, angular, needle-shaped, and plate-shaped; preferably, spherical abrasive grains.

[0024] In one specific embodiment, the abrasive grain size is 10nm~200nm, preferably 20nm~80nm, and more preferably 25nm~50nm. When the abrasive grain size is smaller than the above range, the grinding speed will decrease; when the abrasive grain size exceeds the above range, the grinding uniformity will deteriorate, and scratches may occur.

[0025] In one specific embodiment, the metal or silicon oxide is selected from at least one of silicon dioxide, cerium oxide, zirconium oxide, aluminum oxide, titanium dioxide, barium oxide, germanium oxide, manganese oxide, and magnesium oxide.

[0026] In one specific embodiment, the metal or silicon oxide having an organic or inorganic coating layer is selected from at least one of alumina having a silane coupling agent coating layer, silica having an epoxy silane coating layer, silica having a polydimethylsiloxane coating layer, silica having a titanium dioxide coating layer, and silica having a trimethylsiloxane coating layer.

[0027] In one specific embodiment, the alumina with a silane coupling agent coating is AEROXIDE ALU C805; the silica with an epoxy silane coating is CY-SP30E; the silica with a polydimethylsiloxane coating is HDKH18; the silica with a titanium dioxide coating is DNG-S010; and the silica with a trimethylsiloxane coating is Evonik AEROSIL R 974.

[0028] In one specific embodiment, the metal or silicon oxide colloid is selected from at least one of colloidal cerium oxide, colloidal alumina, and colloidal zirconium oxide.

[0029] In one specific embodiment, the modified colloidal metal or silicon oxide is selected from at least one of α-colloidal alumina, epoxy-modified colloidal silica, and mesoporous colloidal titanium dioxide.

[0030] In one specific embodiment, the α-colloidal alumina is CY-L4; the epoxy-modified colloidal silica is CY-SP30S; and the mesoporous colloidal titanium dioxide is XFI26.

[0031] In one specific embodiment, the abrasive grains are preferably colloidal cerium oxide. Specifically, selecting colloidal cerium oxide, which has high dispersion stability, as the abrasive grains can minimize defects such as scratches while achieving high grinding characteristics.

[0032] In one specific embodiment, in addition to using a single-size (monodispersed) abrasive grains, the present invention can also employ polydisperse abrasive grains (i.e., a system in which the particle size has a certain distribution range). For example, mixing two abrasive grains with different average particle sizes can form a bimodal polydisperse system; mixing three abrasive grains with different average particle sizes can form a trimodal polydisperse system; and mixing four or more abrasive grains with different average particle sizes can form a more complex polydisperse system with a multimodal distribution. By mixing abrasive grains of different sizes in an appropriate proportion, smaller particles can fill the gaps between larger particles, reducing the probability of larger particles directly contacting the wafer surface, thereby reducing scratches to a certain extent.

[0033] In one specific embodiment, the abrasive particles are selected from a first abrasive particle with a particle size of 78nm~82nm and a second abrasive particle with a particle size of 47nm~53nm; wherein, the mass ratio of the first abrasive particle to the second abrasive particle is (0.7~1.1):(0.8~1.2).

[0034] In one specific embodiment, the abrasive particles are selected from a third abrasive particle with a particle size of 78nm~82nm, a fourth abrasive particle with a particle size of 47nm~53nm, and a fifth abrasive particle with a particle size of 28nm~32nm; wherein, the mass ratio of the third abrasive particle, the fourth abrasive particle, and the fifth abrasive particle is (0.7~1.1):(0.8~1.2):(0.7~1.1).

[0035] In one specific embodiment, the abrasive particles are selected from a sixth abrasive particle with a particle size of 88nm~92nm, a seventh abrasive particle with a particle size of 78nm~82nm, an eighth abrasive particle with a particle size of 47nm~53nm, and a ninth abrasive particle with a particle size of 28nm~32nm; wherein, the mass ratio of the sixth abrasive particle, the seventh abrasive particle, the eighth abrasive particle, and the ninth abrasive particle is (0.7~1.1):(0.7~1.1):(0.8~1.2):(0.7~1.1).

[0036] In one specific embodiment, the nonionic copolymer dispersant used in this invention has both hydrophilic groups (such as hydroxyl-OH) and hydrophobic groups (such as alkyl groups). The hydrophilic groups are bonded to the polar sites on the surface of the film being polished through hydrogen bonds, which can increase the surface hydrophilicity and promote the uniform spreading of the polishing slurry, thereby improving its polishing uniformity. The hydrophobic groups can maintain physical stability by reducing the water absorption and swelling of the polishing pad, promote the uniform distribution of the polishing slurry and accelerate the removal of polishing debris, thereby improving the polishing uniformity.

[0037] In one specific embodiment, the nonionic copolymer dispersant is selected from at least one of the compounds represented by chemical formula 1 and chemical formula 2.

[0038] Chemical Formula 1: R1-(EO) x -(PO) y -R2;

[0039] Wherein, R1 and R2 are selected from alkyl or alkoxy groups containing 1 to 10 C atoms, E and P are selected from substituted or unsubstituted alkylene groups containing 2 to 3 C atoms, and the two are different, and x and y are selected from integers from 1 to 200.

[0040] Chemical formula 2: R1-(EO) x -(PO) y -(EO) z -R2;

[0041] R1 and R2 are selected from alkyl or alkoxy groups containing 1 to 10 C atoms, E and P are selected from substituted or unsubstituted alkylene groups containing 2 to 3 C atoms, and the two are different, and x, y, and z are selected from integers from 1 to 200.

[0042] In one specific embodiment, the molar ratio of ethylene oxide to propylene oxide in the EO / PO block copolymer is 1:3 to 3:1. Specifically, the grinding slurry prepared by selecting a molar ratio of ethylene oxide to propylene oxide within this range can further ensure grinding uniformity and grinding rate.

[0043] In one specific embodiment, the hydroxyl value of the nonionic copolymer dispersant ranges from 5 to 400 mg KOH / g. This optimizes the grinding uniformity and rate of the film being ground, maximizing grinding speed while ensuring grinding efficiency. If the hydroxyl value is less than 5 mg KOH / g, insufficient hydrogen bonds on the surface of the ground film will reduce its hydrophilicity, leading to decreased grinding uniformity. If the hydroxyl value is greater than 400 mg KOH / g, both grinding speed and grinding uniformity will decrease.

[0044] In one specific embodiment, the weight-average molecular weight of the nonionic copolymer dispersant is 1000-10000, preferably 2000-8000, and more preferably 5000-6000. When the weight-average molecular weight of the nonionic copolymer exceeds 10000, the grinding speed will decrease; when the weight-average molecular weight of the nonionic copolymer is less than 1000, the grinding uniformity will decrease.

[0045] In one specific embodiment, the compound represented by Formula 1 is selected from at least one of dipropylene glycol ethylene oxide / propylene oxide copolymer, butanol ethylene oxide / propylene oxide copolymer, and lauryl alcohol ethylene oxide / propylene oxide copolymer.

[0046] In one specific embodiment, the compound represented by Formula 2 is selected from at least one of butanol ethylene oxide / propylene oxide / ethylene oxide copolymer, lauryl ethylene oxide / propylene oxide / ethylene oxide copolymer, and propanol ethylene oxide / propylene oxide / ethylene oxide copolymer.

[0047] In one specific embodiment, the pH buffer is selected from at least one of histidine, lysine, and arginine. The pH buffer helps maintain the dispersibility and dispersion stability of the abrasive particles by keeping the system's pH stable, reducing the formation of precipitates due to pH fluctuations.

[0048] In one specific embodiment, the organic acid is selected from at least one of acetic acid, lactic acid, pimelic acid, malic acid, malonic acid, maleic acid, adipic acid, oxalic acid, succinic acid, tartaric acid, citric acid, glutaric acid, glycolic acid, formic acid, fumaric acid, propionic acid, butyric acid, hydroxybutyric acid, aspartic acid, itaconic acid, tricarboxylic acid, octanoic acid, sebacic acid, stearic acid, pyruvic acid, acetoacetic acid, glyoxylic acid, azelaic acid, caprylic acid, lauric acid, myristic acid, valeric acid, and palmitic acid.

[0049] In one specific embodiment, the pH adjuster is selected from at least one of ammonia, methylpropoxide, tetramethylammonium hydroxide, potassium hydroxide, sodium hydroxide, magnesium hydroxide, rubidium hydroxide, cesium hydroxide, sodium bicarbonate, sodium carbonate, triethanolamine, nicotinamide, nitric acid, sulfuric acid, phosphoric acid, hydrochloric acid, acetic acid, citric acid, glutaric acid, gluconic acid, formic acid, acetic acid, malic acid, malonic acid, maleic acid, oxalic acid, phthalic acid, tert-butyric acid, and tartaric acid.

[0050] In one specific embodiment, the surfactant is selected from cationic surfactants. Specifically, adding a cationic surfactant to the system allows the surface of the abrasive particles to carry a positive charge, thereby utilizing the electrostatic repulsion between charges to achieve stable dispersion of the abrasive particles.

[0051] In one specific embodiment, the surfactant is selected from at least one of primary amine salts, secondary amine salts, tertiary amine salts, and quaternary ammonium salts.

[0052] In one specific embodiment, the surfactant is selected from at least one of dodecylamine hydrochloride, octylamine sulfate, hexadecylamine phosphate, dioctylamine hydrochloride, dodecylpropylamine acetate, didecylamine sulfate, dodecyldimethylamine hydrochloride, hexadecyldiethylamine phosphate, octadecyldimethylamine sulfate, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, and benzyldodecyldimethylammonium chloride.

[0053] In one specific embodiment, the viscosity modifier is selected from at least one of polyethylene glycol, polypropylene glycol, polyvinylpyrrolidone, polyoxyalkylene ether, polyoxyalkylene ester, polyoxyalkylene methyl ether, polyethylene glycol sulfonic acid, polyvinyl alcohol, polyethylene oxide-propylene oxide copolymer, cellulose, methylcellulose, methyl hydroxyethylcellulose, methyl hydroxypropylcellulose, hydroxyethylcellulose, carboxymethylcellulose, sulfoethylcellulose, and carboxymethyl sulfoethylcellulose.

[0054] In one specific embodiment, the corrosion inhibitor is selected from at least one of benzotriazole and toluenetriazole. By inhibiting excessive corrosion of copper with the corrosion inhibitor and achieving precise grinding in conjunction with pH adjustment of the system, a continuous and smooth effect can be achieved between the barrier layer, the metal layer, and the dielectric layer.

[0055] In one specific embodiment, the oxidant is selected from at least one of hydrogen peroxide, nitric acid, and sulfuric acid.

[0056] In one specific embodiment, the second additive is selected from at least one of glycine, benzotriazole, citric acid, polyacrylic acid, complexing agents, and organosilane compounds.

[0057] In one specific embodiment, the organosilane compound is selected from at least one of MTMS (methyltrimethoxysilane), PTMS (phenyltrimethoxysilane), and VTMS (vinyltrimethoxysilane).

[0058] In one specific embodiment, the complexing agent is selected from at least one of ATMP (aminotrimethylenephosphonic acid) and HEDTA (hydroxyethyl ethylenediamine triacetic acid).

[0059] In one specific embodiment, the pH of the grinding slurry is preferably 3 to 6, more preferably 3.5 to 5.5.

[0060] The present invention also discloses a method for preparing a polishing slurry for a 14-nanometer CMP process as described above, comprising the following steps: mixing abrasive particles, a nonionic copolymer dispersant, a pH buffer, an organic acid, a pH adjuster, a surfactant, a viscosity modifier, a corrosion inhibitor, an oxidant, a first additive, a second additive, and ultrapure water to obtain a polishing slurry.

[0061] In one specific embodiment, the preparation method includes: adding an appropriate amount of ultrapure water to a stirred tank and stirring at low speed at room temperature to ensure uniform water flow; adding a pH adjuster and a pH buffer in sequence and stirring for 5-10 minutes to ensure uniform mixing of the system; slowly and uniformly adding abrasive particles to the stirred tank while increasing the stirring speed to high speed, and continuing to stir for 5-10 minutes after all particles have been added; adding a nonionic copolymer dispersant and stirring for 15-30 minutes; adjusting the stirring speed to low speed and adding a surfactant, organic acid, corrosion inhibitor, first auxiliary additive, second auxiliary additive, oxidant, and viscosity modifier in sequence, stirring for 5-15 minutes after each additive is added; adding ultrapure water to the target total mass and continuing to stir for 10-20 minutes to ensure uniform mixing of the system.

[0062] The present invention also discloses a polishing slurry for a 14-nanometer CMP process as described above, or the application of a polishing slurry prepared by the preparation method described above in a 14-nanometer CMP process.

[0063] In one specific embodiment, the polishing rate of the polishing slurry on the silicon oxide film is 4,000 Å / min to 8,000 Å / min.

[0064] In one specific embodiment, the polishing rate of the polishing slurry on the Cu metal layer is 200 nm / min to 400 nm / min.

[0065] In one specific embodiment, the polishing slurry polishes TaN at a rate of 4.2 nm / min to 7.5 nm / min.

[0066] In one specific embodiment, the grinding selectivity ratio of the grinding slurry for Cu to TaN is ≥50:1.

[0067] In one specific embodiment, the Zeta potential between the Cu metal layer and the TaN layer in the polishing slurry is 15mV~30mV.

[0068] The following are specific embodiments.

[0069] Example 1

[0070] The polishing slurry (pH 5.5) used in the 14nm CMP process of this embodiment comprises the following components by weight percentage: 1.35wt% colloidal cerium oxide (particle size 50nm) as abrasive, 0.01wt% Ethylan 324 as a nonionic copolymer dispersant, 0.21wt% histidine as a pH buffer, 0.01wt% acetic acid and 12wt% citric acid as organic acids, 0.05wt% tetramethylammonium hydroxide as a pH adjuster, 0.05wt% dodecylamine hydrochloride as a surfactant, 0.1wt% methyl hydroxypropyl cellulose as a viscosity modifier, 0.05wt% toluenetriazole as a corrosion inhibitor, 0.8wt% hydrogen peroxide as an oxidant, 1wt% a first additive, 1wt% glycine as a second additive, and the balance being ultrapure water as a dispersion medium. The first additive comprises 3-sulfopropyltetradecyl dimethyl betaine (CAS No.: 14933-09-6) and 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane (CAS No.: 14712-23-3) in a mass ratio of 8:1.

[0071] The preparation method of the polishing slurry for the 14nm CMP process in this embodiment is as follows: Add an appropriate amount of ultrapure water to a stirred tank and stir at low speed at room temperature to ensure uniform water flow; add tetramethylammonium hydroxide and histidine in sequence and stir for 5 minutes to make the system uniformly mixed; add colloidal cerium oxide slowly and uniformly to the stirred tank while increasing the stirring speed to high speed, and continue stirring for 10 minutes after all the cerium oxide has been added; add Ethylan 324 and stir for 20 minutes; adjust the stirring speed to low speed and add dodecylamine hydrochloride, acetic acid and citric acid, toluenetriazole, 3-sulfopropyltetradecyl dimethyl betaine and 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane, glycine, hydrogen peroxide, and methyl hydroxypropyl cellulose in sequence, stirring for 10 minutes after each additive is added; add ultrapure water to the target total mass and continue stirring for 15 minutes to make the system uniformly mixed.

[0072] Example 2

[0073] The difference between this embodiment and Example 1 is that the composition and weight ratio of the polishing slurry have been adjusted. The polishing slurry (pH 4.5) used in this embodiment for the 14nm CMP process includes the following components by weight percentage:

[0074] 1.35 wt% colloidal cerium oxide (80 nm particle size) was used as abrasive particles; 0.05 wt% Ethylan 324 was used as a nonionic copolymer dispersant; 0.21 wt% lysine was used as a pH buffer; 12.1 wt% citric acid was used as an organic acid; 0.01 wt% sodium bicarbonate was used as a pH adjuster; 0.01 wt% hexadecylamine phosphate was used as a surfactant; 0.1 wt% hydroxyethyl cellulose was used as a viscosity modifier; 0.05 wt% toluenetriazole was used as a corrosion inhibitor; 0.5 wt% nitric acid was used as an oxidant; 1 wt% of a first additive was used; 1 wt% of polyacrylic acid was used as a second additive; and the balance was ultrapure water as the dispersion medium. The first additive consisted of 3-sulfopropyltetradecyl dimethyl betaine and 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane in a mass ratio of 8:1.

[0075] Example 3

[0076] The difference between this embodiment and Example 1 is that the composition and weight ratio of the polishing slurry have been adjusted. The polishing slurry (pH 3.5) used in this embodiment for the 14nm CMP process includes the following components by weight percentage:

[0077] 1.35 wt% colloidal cerium oxide (30 nm particle size) was used as abrasive particles; 0.03 wt% Ethylan 324 was used as a nonionic copolymer dispersant; 0.21 wt% arginine was used as a pH buffer; 14 wt% itaconic acid was used as an organic acid; 0.01 wt% sodium bicarbonate was used as a pH adjuster; 0.1 wt% didecylamine sulfate was used as a surfactant; 0.1 wt% polyethylene glycol was used as a viscosity modifier; 0.01 wt% toluenetriazole was used as a corrosion inhibitor; 1.5 wt% hydrogen peroxide was used as an oxidant; 1 wt% of a first additive was used; 1 wt% of polyacrylic acid was used as a second additive; and the balance was ultrapure water as the dispersion medium. The first additive consisted of 3-sulfopropyltetradecyl dimethyl betaine and 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane in a mass ratio of 8:1.

[0078] Comparative Example 1

[0079] A CMP polishing slurry with a pH of 5 was prepared using 1.35 wt% colloidal cerium oxide (50 nm) as abrasive, 0.01 wt% butanol ethylene oxide / propylene oxide copolymer (product name: Ethylan NS500LQ) as a nonionic copolymer, 0.21 wt% histidine as a pH buffer, 0.02 wt% acetic acid and 12 wt% itaconic acid as organic acids, 0.1 wt% dodecylamine hydrochloride as a surfactant, 0.5 wt% hydrogen peroxide (H2O2) as an oxidant, 0.01 wt% benzotriazole as a corrosion inhibitor, 0.01 wt% hydroxypropyl cellulose as a viscosity modifier, 1 wt% arginine as an additive, and ultrapure water as a dispersion medium.

[0080] Comparative Example 2

[0081] A CMP polishing slurry with a pH of 5.5 was prepared using 1.35 wt% colloidal cerium oxide (50 nm) as abrasive particles, 0.015 wt% polyglycerol as a nonionic copolymer, 0.25 wt% histidine as a pH buffer, 0.02 wt% acetic acid and 12 wt% itaconic acid as organic acids, 0.1 wt% dodecylamine hydrochloride as a surfactant, 1.2 wt% hydrogen peroxide (H2O2) as an oxidant, 0.01 wt% benzotriazole as a corrosion inhibitor, 0.01 wt% hydroxypropyl cellulose as a viscosity modifier, 1 wt% arginine as an additive, and ultrapure water as a dispersion medium.

[0082] Examples 4-10

[0083] Examples 4-10 differ from Example 1 only in that the colloidal cerium oxide abrasive grains are replaced with other abrasive grains as shown in Table 1.

[0084] Table 1

[0085]

[0086] In Example 6, the silicon dioxide with a titanium dioxide coating is DNG-SO10.

[0087] The silica with an epoxy silane coating in Example 8 is CY-SP30E.

[0088] The α-colloidal alumina in Example 9 is CY-L4.

[0089] The mesoporous colloidal titanium dioxide in Example 10 is XF126.

[0090] Examples 11-13

[0091] Compared with Example 1, Examples 11-13 differ only in that the single-size colloidal cerium oxide abrasive grains are replaced with multi-size colloidal cerium oxide abrasive grains as shown in Table 2.

[0092] Table 2

[0093]

[0094] Examples 14-15, Comparative Examples 3-4

[0095] Examples 14-15 and Comparative Examples 3-4 differ from Example 1 only in that the mass ratio of 3-sulfopropyltetradecyl dimethyl betaine and 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane is replaced with the mass ratios shown in Table 3.

[0096] Table 3

[0097]

[0098] Comparative Example 5

[0099] The only difference between this comparative example and Example 1 is that 3-sulfopropyltetradecyl dimethyl betaine is not added, and the amount of 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane added in this comparative example is adjusted to 1 wt%.

[0100] Comparative Example 6

[0101] The only difference between this comparative example and Example 1 is that 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane is not added, and the amount of 3-sulfopropyltetradecyl dimethyl betaine added in this comparative example is adjusted to 1 wt%.

[0102] Comparative Example 7

[0103] The only difference between this comparative example and Example 1 is that 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane and 3-sulfopropyltetradecyl dimethyl betaine are not added.

[0104] Comparative Examples 8-9 and Examples 16-18

[0105] Compared with Example 1, the only difference is that the amount of colloidal cerium oxide (particle size of 50nm) abrasive particles added was adjusted to 0.05wt% (Comparative Example 8), 0.1wt% (Example 16), 5wt% (Example 17), 10wt% (Example 18), and 15wt% (Comparative Example 9), respectively.

[0106] Comparative Examples 10-11 and Examples 19-20

[0107] Compared with Example 1, the only difference is that the amount of organic acid added was adjusted to 5 wt% (Comparative Example 10), 10 wt% (Example 19), 20 wt% (Example 20), and 25 wt% (Comparative Example 11), respectively.

[0108] Test case

[0109] The CMP process was carried out using the CMP slurry prepared in the above examples and comparative examples under the following grinding conditions (Table 4).

[0110] Table 4

[0111]

[0112] The grinding unevenness can be calculated using the following formula.

[0113] Within-Wafer Non-Uniformit (WIWNU) = (Standard deviation of grinding speed / Average grinding speed) × 100%

[0114] The lower the grinding non-uniformity value, the higher the grinding uniformity. The grinding non-uniformity of the present invention is 6.5% or less, preferably 3.5% or less, and more preferably 1.5% or less.

[0115] Table 5 below describes the composition of the two products used as nonionic copolymers, and Tables 6-7 show the comparison of the effects of the examples and comparative examples.

[0116] Table 5

[0117]

[0118] Table 6

[0119]

[0120] Table 7

[0121]

[0122] As shown in Tables 6-7, this invention improves grinding speed while ensuring grinding uniformity and reducing grinding defects. The contact angle in the embodiment is larger than that in the comparative example; that is, the use of a nonionic copolymer dispersant effectively increases the hydrophobicity of the grinding film surface, thereby promoting uniform distribution of the grinding fluid and accelerating the removal of grinding debris, thus improving grinding uniformity. Under the same grinding conditions, this invention achieves higher grinding speeds and lower grinding non-uniformity for SiO2, Cu, and TaN. Therefore, this invention improves grinding efficiency while reducing grinding defects. Furthermore, by changing the proportion of different components in the grinding fluid, the grinding selectivity during the grinding process can be adjusted, making this invention applicable to the grinding of various types of substrates.

[0123] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A slurry for 14 nm CMP process, characterized by, Includes the following components by weight percentage: 0.1wt%~10wt% abrasive particles, 0.001wt%~0.5wt% nonionic copolymer dispersant, 0.01wt%~1wt% pH buffer, 10wt%~20wt% organic acid, 0.01wt%~1wt% pH adjuster, 0.01wt%~1wt% surfactant, 0.1wt%~1wt% viscosity modifier, 0.01wt%~0.1wt% corrosion inhibitor, 0.5wt%~5wt% oxidant, 0.5wt%~2wt% first additive, 0.5wt%~2wt% second additive, balance ultrapure water; The nonionic copolymer dispersant is an EO / PO block copolymer; The first additive comprises 3-sulfopropyltetradecyl dimethyl betaine and 1-[N-(2-hydroxyethyl)-4'-piperidinyl]-3-(4'-piperidinyl)propane in a mass ratio of (5~10):1; The molar ratio of ethylene oxide to propylene oxide in the EO / PO block copolymer is 1:3 to 3:

1. The nonionic copolymer dispersant has a hydroxyl value ranging from 5 to 400 mg KOH / g; the nonionic copolymer dispersant has a weight-average molecular weight of 1000 to 10000. The pH buffer is selected from at least one of histidine, lysine and arginine; The organic acid is selected from at least one of acetic acid, lactic acid, pimelic acid, malic acid, malonic acid, maleic acid, adipic acid, oxalic acid, succinic acid, tartaric acid, citric acid, glutaric acid, glycolic acid, formic acid, fumaric acid, propionic acid, butyric acid, hydroxybutyric acid, aspartic acid, itaconic acid, tricarboxylic acid, octanoic acid, sebacic acid, stearic acid, pyruvic acid, acetoacetic acid, glyoxylic acid, azelaic acid, caprylic acid, lauric acid, myristic acid, valeric acid, and palmitic acid. The pH adjuster is selected from at least one of ammonia, methylpropoxide, tetramethylammonium hydroxide, potassium hydroxide, sodium hydroxide, magnesium hydroxide, rubidium hydroxide, cesium hydroxide, sodium bicarbonate, sodium carbonate, triethanolamine, nicotinamide, nitric acid, sulfuric acid, phosphoric acid, hydrochloric acid, acetic acid, citric acid, glutaric acid, gluconic acid, formic acid, acetic acid, malic acid, malonic acid, maleic acid, oxalic acid, phthalic acid, tert-butyric acid, and tartaric acid. The surfactant is selected from cationic surfactants; The viscosity modifier is selected from at least one of polyethylene glycol, polypropylene glycol, polyvinylpyrrolidone, polyoxyalkylene ether, polyoxyalkylene ester, polyoxyalkylene methyl ether, polyethylene glycol sulfonic acid, polyvinyl alcohol, polyethylene oxide-propylene oxide copolymer, cellulose, methylcellulose, methyl hydroxyethylcellulose, methyl hydroxypropylcellulose, hydroxyethylcellulose, carboxymethylcellulose, sulfoethylcellulose, and carboxymethyl sulfoethylcellulose; The corrosion inhibitor is selected from at least one of benzotriazole and toluenetriazole; The oxidant is selected from at least one of hydrogen peroxide, nitric acid, and sulfuric acid; The second additive is selected from at least one of glycine, benzotriazole, citric acid, polyacrylic acid, complexing agent, and organosilane compound.

2. The polishing slurry for 14nm CMP process according to claim 1, characterized in that, The abrasive particles are selected from at least one of metal oxides or silicon oxides, metal oxides or silicon oxides with organic or inorganic coatings, colloidal metal oxides or silicon oxides, and modified colloidal metal oxides or silicon oxides. The shape of the abrasive grains is selected from at least one of spherical, angular, needle-shaped, and plate-shaped. The abrasive grains have a particle size of 10nm~200nm.

3. The polishing slurry for 14nm CMP process according to claim 2, characterized in that, The metal oxide or silicon oxide is selected from at least one of silicon dioxide, cerium oxide, zirconium oxide, aluminum oxide, titanium dioxide, barium oxide, germanium oxide, manganese oxide and magnesium oxide; The metal oxide or silicon oxide having an organic or inorganic coating layer is selected from at least one of the following: alumina having a silane coupling agent coating layer, silicon dioxide having an epoxy silane coating layer, silicon dioxide having a polydimethylsiloxane coating layer, silicon dioxide having a titanium dioxide coating layer, and silicon dioxide having a trimethylsiloxane coating layer. The metal oxide or silicon oxide colloid is selected from at least one of colloidal cerium oxide, colloidal aluminum oxide, and colloidal zirconium oxide; The modified colloidal metal oxide or silicon oxide is selected from at least one of α-colloidal alumina, epoxy-modified colloidal silica, and mesoporous colloidal titanium dioxide.

4. The polishing slurry for 14nm CMP process according to claim 2, characterized in that, The abrasive particles are selected from a first abrasive particle with a particle size of 78nm~82nm and a second abrasive particle with a particle size of 47nm~53nm; wherein the mass ratio of the first abrasive particle to the second abrasive particle is (0.7~1.1):(0.8~1.2). The abrasive particles are selected from a third abrasive particle with a particle size of 78nm~82nm, a fourth abrasive particle with a particle size of 47nm~53nm, and a fifth abrasive particle with a particle size of 28nm~32nm; wherein the mass ratio of the third abrasive particle, the fourth abrasive particle, and the fifth abrasive particle is (0.7~1.1):(0.8~1.2):(0.7~1.1). The abrasive particles are selected from the sixth abrasive particle with a particle size of 88nm~92nm, the seventh abrasive particle with a particle size of 78nm~82nm, the eighth abrasive particle with a particle size of 47nm~53nm, and the ninth abrasive particle with a particle size of 28nm~32nm; wherein, the mass ratio of the sixth abrasive particle, the seventh abrasive particle, the eighth abrasive particle, and the ninth abrasive particle is (0.7~1.1):(0.7~1.1):(0.8~1.2):(0.7~1.1).

5. The polishing slurry for 14nm CMP process according to claim 1, characterized in that, The nonionic copolymer dispersant is selected from at least one of the compounds shown in chemical formula 1 and chemical formula 2; Chemical Formula 1: R1-(EO) x -(PO) y -R2; Wherein, R1 and R2 are selected from alkyl or alkoxy groups containing 1 to 10 C atoms, E and P are selected from substituted or unsubstituted alkylene groups containing 2 to 3 C atoms, and the two are different, and x and y are selected from integers from 1 to 200. Chemical Formula 2: R1-(EO) x -(PO) y -(EO) z -R2; R1 and R2 are selected from alkyl or alkoxy groups containing 1 to 10 C atoms, E and P are selected from substituted or unsubstituted alkylene groups containing 2 to 3 C atoms, and the two are different, and x, y, and z are selected from integers from 1 to 200.

6. The polishing slurry for 14nm CMP process according to claim 1, characterized in that, The pH of the grinding fluid is 3-6.

7. A method for preparing a polishing slurry for a 14nm CMP process as described in any one of claims 1-6, characterized in that, Includes the following steps: The grinding fluid is obtained by mixing abrasive particles, nonionic copolymer dispersant, pH buffer, organic acid, pH adjuster, surfactant, viscosity modifier, corrosion inhibitor, oxidant, first additive, second additive and ultrapure water.

8. A polishing slurry for a 14nm CMP process as described in any one of claims 1-6, or the application of a polishing slurry prepared by the preparation method as described in claim 7 in a 14nm CMP process.

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