A cleaning agent for CMP polishing, a preparation method and application thereof

Abstract

This invention provides a cleaning agent for CMP polishing, its preparation method, and its application, belonging to the field of semiconductor manufacturing process technology. The cleaning agent for CMP polishing comprises a multi-component synergistic system consisting of a first nitrogen-containing compound, a second nitrogen-containing compound, a third nitrogen-containing compound, a surfactant, a pH buffer, and deionized water. It can effectively remove submicron-sized abrasive particles and complex organic contaminants remaining after CMP, while controlling the micro-roughness of the substrate surface and widening the process pH window, achieving a highly efficient, low-damage, and stable cleaning effect.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing process technology, and in particular to a cleaning agent for CMP polishing, its preparation method, and its application. Background Technology

[0002] In semiconductor manufacturing processes, chemical mechanical polishing (CMP) is a key step in achieving global planarization of the surface of multilayer interconnect structures and is widely used in the fabrication of logic devices and memory devices. With the continuous miniaturization of device dimensions and the evolution of three-dimensional structures, such as the introduction of advanced transistor architectures like FinFET and GAA (Gate-All-Around), the requirements for the cleanliness of the substrate surface after CMP have significantly increased.

[0003] To remove residual contaminants after CMP (Chemical Metallurgy Processing), the industry commonly employs multi-step wet cleaning processes. The composition design of the cleaning agent directly impacts particle removal efficiency, surface morphology retention, and process repeatability. Existing cleaning agents are mostly constructed based on alkaline systems, often containing quaternary ammonium bases, organic amines, metal corrosion inhibitors, and organic acid additives. Contaminant desorption and dispersion are achieved by controlling pH, complexing ability, and interfacial wettability. Some solutions introduce α-hydroxydicarboxylic acids such as tartaric acid as auxiliary complexing components to stabilize metal ions and inhibit their redeposition on silicon-based surfaces. The purity of tartaric acid, the content of trace metal impurities, and the overall pH range of the solution are identified as key parameters affecting cleaning effectiveness. Its concentration in the composition is typically controlled between 0.1 wt% and 5 wt%, and the system pH is maintained in the range of 9–12 to balance the chemical stability of the silicon-based material with the solubility / dispersion performance of contaminants.

[0004] Although the solution in TW202530384A can remove most of the residues, with the continuous evolution of semiconductor process nodes, especially towards 3nm and below, the requirements for wafer surface cleanliness have reached a near-atomic level of stringency.

[0005] As semiconductor process nodes evolve towards 3nm and below, the requirements for wafer surface cleanliness have reached near-atomic levels of stringency. Although the solution in TW202530384A can remove most residues, it still reveals several shortcomings when facing advanced nodes: First, existing cleaning agents sometimes struggle to completely remove smaller, more firmly adsorbed colloidal silica abrasive particles, posing a risk of "under-cleaning." Second, novel polishing slurry additives used in advanced processes often contain polymers with more complex structures, and existing cleaning agents have limited ability to dissolve or disperse them. If the chemical etching process is not uniform, it may increase the surface micro-roughness of sensitive substrates (such as amorphous silicon or polycrystalline silicon layers), thereby affecting the integrity of subsequent gate oxide layers and channel mobility. Furthermore, the performance of existing compositions is highly sensitive to changes in process conditions such as pH and temperature, resulting in a narrow process window that is difficult to adapt to the stability and tolerance requirements of large-scale production environments. Therefore, how to efficiently remove submicron-sized abrasive particles and complex organic residues while effectively controlling surface micro-roughness and widening the process window has become a pressing technical problem to be solved in this field. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a cleaning agent for CMP polishing, its preparation method, and its application. This invention can solve the technical problem of existing technologies struggling to completely remove submicron-sized abrasive particles and complex organic residues when dealing with advanced semiconductor nodes, while effectively controlling surface micro-roughness and widening the process window.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A cleaning agent for CMP polishing, characterized in that it comprises: First nitrogen-containing compound: at least two of the following compounds having one amine group and one or more hydroxyl groups and having a total number of carbon atoms of 1 to 6; The second nitrogen-containing compound: a cage-like diamine, wherein the cage-like diamine is selected from at least one of triethylenediamine, 1,5-diazabicyclo[4.3.0]non-5-ene and 1,8-diazabicyclo[5.4.0]undec-7-ene; The third nitrogen-containing compound: hexamethylenetetramine; Surfactants: alkyl betaine and / or sulfobetaine; pH buffer: N-carbamoylmethylethanesulfonic acid and / or N-(2-acetamido)-2-aminoethanesulfonic acid; The remainder is deionized water.

[0008] Preferably, the first nitrogen-containing compound includes at least two of 2-aminoethanol, 1-amino-2-propanol, 3-amino-1-propanol, ethanolamine, 2-(methylamino)ethanol, 2-amino-2-methyl-1-propanol, 1-dimethylamino-2-propanol, diethanolamine, triethanolamine, 3-amino-1,2-propanediol, 2-amino-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol, and 2-amino-2-ethyl-1,3-propanediol.

[0009] Preferably, the amount of the first nitrogen-containing compound added is 0.1% to 10%; the amount of the second nitrogen-containing compound added is 0.05% to 0.2%; the amount of the third nitrogen-containing compound added is 0.1% to 0.5%; the amount of the surfactant added is 0.01% to 0.2%; and the amount of the pH buffer added is 0.05% to 0.5%.

[0010] Preferably, the alkyl betaine includes at least one of cocamidopropyl betaine, octamidopropyl betaine, and octyl / decamidopropyl betaine.

[0011] Preferably, the sulfobetaine comprises butyl octyl ether hydroxypropyl sulfobetaine and / or dodecyl hydroxypropyl sulfobetaine.

[0012] Preferably, the pH of the cleaning agent is 6 to 10.5.

[0013] Preferably, the pH of the cleaning agent is controlled by a pH adjuster selected from at least one of ammonia, acetic acid, and potassium hydroxide.

[0014] The present invention further provides a method for preparing the above-mentioned cleaning agent for CMP polishing, comprising the following steps: adding a first nitrogen-containing compound, a second nitrogen-containing compound, a third nitrogen-containing compound, a surfactant and a pH buffer to deionized water in a certain proportion, stirring at 20~30°C until completely dissolved, and adjusting the pH value to obtain the cleaning agent for CMP polishing.

[0015] The present invention further provides an application of the above-mentioned CMP polishing cleaning agent or the CMP polishing cleaning agent prepared by the above method in chemical mechanical polishing, wherein the above-mentioned CMP polishing cleaning agent is used to clean the semiconductor substrate, thereby reducing the residue on the surface of the semiconductor substrate with silicon-silicon bonds after polishing.

[0016] Preferably, the semiconductor substrate includes an amorphous silicon substrate, a polycrystalline silicon substrate, or a monocrystalline silicon substrate.

[0017] Beneficial effects: This application provides a cleaning agent for CMP polishing, comprising a first nitrogen-containing compound, a second nitrogen-containing compound, a cage-like diamine, a third nitrogen-containing compound, hexamethylenetetramine, a surfactant, and a pH buffer, with the balance being deionized water, forming a multi-component synergistic system. Specifically, by selecting a first nitrogen-containing compound having one or more amine groups and a limited number of carbon atoms, the nucleophilic attack capability of its amine group and the hydrogen bonding force of its hydroxyl groups are utilized to achieve mild and controllable etching of the substrate surface and strong adsorption and solubilization of contaminants. A cage-like diamine with a specific structure is introduced as the second nitrogen-containing compound, which, with its unique spatial configuration and high electron cloud density, catalyzes the decomposition of complex organic residues and chelates metal ions, while synergistically stabilizing the interfacial microenvironment with the first nitrogen-containing compound. Hexamethylenetetramine is compounded as... The third nitrogen-containing compound plays a role in corrosion inhibition and morphology control, adjusting the anisotropy of etching to prevent local over-etching. Combined with alkyl betaine and / or sulfobetaine, its zwitterionic properties reduce surface tension and form steric hindrance, effectively encapsulating the stripped microparticles and preventing their re-adsorption. Finally, relying on the excellent buffering performance of the pH buffer, the system maintains high acidity and alkalinity stability over a wide pH range, ensuring that the cleaning process is not affected by external interference. This effectively solves the technical problems of difficult removal of submicron abrasive particles, incomplete cleaning of complex organic residues, increased surface roughness, and narrow process windows at advanced nodes, avoiding the risk of device performance degradation due to uneven cleaning. It achieves a high-cleanliness, low-damage, and high-stability cleaning effect, significantly improving the yield and reliability of semiconductor manufacturing. Detailed Implementation

[0018] The present application will now be described in further detail with reference to embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the scope of the application.

[0019] This invention provides a cleaning agent for CMP polishing, its preparation method, and its application. The agent comprises a first nitrogen-containing compound, a second nitrogen-containing compound (cage-like diamine), a third nitrogen-containing compound (hexamethylenetetramine), a surfactant, a pH buffer, and deionized water, forming a multi-component synergistic system. Through the synergistic effects of multiple mechanisms, including chemical etching, catalytic decomposition, metal chelation, dispersion to prevent re-adsorption, and interfacial pH stabilization, the overall technical solution of this invention is achieved. This solution aims to address the technical problem of thoroughly removing submicron-sized abrasive particles and complex organic residues after CMP at advanced semiconductor nodes, while simultaneously controlling surface micro-roughness and widening the process window.

[0020] In this invention, the CMP polishing cleaning agent comprises a first nitrogen-containing compound: at least two compounds having one or more amine groups and one or more hydroxyl groups, and having a total number of carbon atoms of 1 to 6. In this invention, the first nitrogen-containing compound comprises at least two of 2-aminoethanol, 1-amino-2-propanol, 3-amino-1-propanol, ethanolamine, 2-(methylamino)ethanol, 2-amino-2-methyl-1-propanol, 1-dimethylamino-2-propanol, diethanolamine, triethanolamine, 3-amino-1,2-propanediol, 2-amino-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol, and 2-amino-2-ethyl-1,3-propanediol. By limiting the first nitrogen-containing compound to a monoamine-polyhydroxy small molecule with the above-mentioned specific structure and mandating the combined use of "at least two," this invention enables molecules with different carbon chain lengths, hydroxyl numbers, and branched structures to exhibit a cooperative effect during the cleaning process.

[0021] In a specific embodiment of the present invention, the first nitrogen-containing compound is preferably a combination of 2-aminoethanol and 3-amino-1,2-propanediol. In this embodiment, the smaller molecule compound (2-aminoethanol) is responsible for rapidly penetrating to the contaminant interface and initiating the initial etching, while the compound with additional hydroxyl groups or multiple branches (3-amino-1,2-propanediol) is responsible for enhancing the stability of the adsorption layer and emulsifying organic contaminants. This structurally specific combination avoids the cleaning blind spots caused by a single component, thereby ensuring the removal efficiency of stubborn abrasive particles while further balancing the etching rate of the substrate surface, making the improvement effect on surface micro-roughness more significant.

[0022] In this invention, the cleaning agent for CMP polishing includes a second nitrogen-containing compound: cage-like diamine; in this invention, the cage-like diamine is selected from at least one of triethylenediamine (DABCO), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU); in this invention, the nitrogen atoms of the cage-like structure in the cage-like diamine have a high electron cloud density and a specific spatial configuration, which enables them to form stable chelates with metal ions (Fe, Cu, etc. in polishing liquid or pipelines), effectively preventing metal ion contamination. More importantly, they can catalyze the decomposition reaction of complex organic polishing additives such as esters and amides, significantly improving the removal ability of stubborn organic residues.

[0023] In this invention, the cleaning agent for CMP polishing includes a third nitrogen-containing compound: hexamethylenetetramine; The third nitrogen-containing compound, hexamethylenetetramine, in this invention functions as a corrosion inhibitor and morphology control agent, adjusting the anisotropy of etching and forming a supramolecular network with the first and second nitrogen-containing compounds. This network uniformly covers the substrate surface to prevent localized over-etching and also prevents unnecessary corrosion of any metal (Cu, Co, etc.) wiring on the substrate by the cleaning solution, ultimately resulting in an atomically flat surface. In this invention, the third nitrogen-containing compound, hexamethylenetetramine, has multiple coordination sites. When used in combination with the first or second nitrogen-containing compounds, it enhances the complexation ability, further strengthening the capture and retention of metal ions.

[0024] In this invention, the cleaning agent for CMP polishing includes surfactants: alkyl betaine and / or sulfobetaine; in this invention, the alkyl betaine includes at least one of cocamidopropyl betaine, octamidopropyl betaine, and octyl / decamidopropyl betaine. This invention selects alkyl betaines with specific long-chain or mixed alkyl structures, utilizing their low critical micelle concentration (CMC) and stable micelle structure to enhance the steric hindrance encapsulation capability of nanoscale silica abrasive particles; its zwitterionic head group is electrically neutral or weakly positively charged in alkaline cleaning solutions, which can both assist in adsorption onto negatively charged substrate surfaces to aid in decontamination and avoid self-residue caused by strong electrostatic adsorption. This significantly improves particle removal rate while ensuring no surfactant film residue remains on the substrate surface after cleaning, further optimizing surface cleanliness.

[0025] In this invention, the sulfobetaine comprises butyl octyl ether hydroxypropyl sulfobetaine and / or dodecyl hydroxypropyl sulfobetaine. This invention, by introducing sulfobetaine containing ether bonds or long alkyl chains, utilizes the excellent salt tolerance and pH stability of the sulfonic acid group, as well as the molecular flexibility provided by the hydroxypropyl spacer arm, to enhance the micellarization ability of the surfactant in complex polishing solution residue environments. The ether bond structure improves the penetration and dissolution ability of polar organic residues, while the long alkyl chain structure strengthens the solubilization effect on non-polar polymer pads. This structural design synergizes with the catalytic decomposition function of cage-like diamines, enabling the cleaning agent to maintain a high removal rate of over 95% when facing diverse organic pollutants.

[0026] In this invention, the cleaning agent for CMP polishing includes a pH buffer: N-carbamoylmethylethanesulfonic acid and / or N-(2-acetamido)-2-aminoethanesulfonic acid; the ethanesulfonic acid pH buffer can interact with the hydroxyl groups in the first nitrogen-containing compound of the cleaning agent, providing a strong pH buffering capacity in the local microenvironment, avoiding the impact of local strong acids or bases, maintaining the stability of the interface pH during the cleaning process, thereby ensuring the uniformity and controllability of the etching rate, and helping to reduce surface roughness.

[0027] In this invention, the pH of the cleaning agent is 6 to 10.5; in this invention, the pH of the cleaning agent is controlled by a pH adjuster, which is selected from at least one of ammonia, acetic acid and potassium hydroxide.

[0028] This invention broadens the pH range of the cleaning agent to 6–10.5, breaking through the limitation that traditional alkaline cleaning agents must rely on high pH values ​​(≥9) for effective cleaning. Within this wide pH range, relying on the buffer pair formed by the pH buffer and the cage-like diamine, the cleaning system can maintain the protonation adsorption capacity of the first nitrogen-containing compound at the acidic end, and maintain the linear controllability of the catalytic activity and etching rate of the cage-like diamine at the neutral and alkaline ends. This avoids local over-etching or cleaning failure caused by pH fluctuations, significantly broadens the process operation window, and adapts to the adaptability requirements of different batches of substrate surface state changes in large-scale production.

[0029] In this invention, the amount of the first nitrogen-containing compound added is preferably 0.1% to 10%, more preferably 1% to 5%; the amount of the second nitrogen-containing compound added is preferably 0.05% to 0.2%, more preferably 0.1% to 0.2%; the amount of the third nitrogen-containing compound added is 0.1% to 0.5%, more preferably 0.1% to 0.2%; the amount of the surfactant added is 0.01% to 0.2%, more preferably 0.1% to 0.2%; and the amount of the pH buffer added is 0.05% to 0.5%, more preferably 0.1% to 0.2%.

[0030] This invention provides a cleaning agent for CMP polishing. By strictly limiting the content of each component within the aforementioned specific range, an optimal balance between chemical activity and surface protection is achieved: First, the nitrogen-containing compound, within this concentration range, provides sufficient etching drive to remove contaminants while avoiding excessive corrosion of the silicon surface due to excessive alkalinity caused by high concentrations; second, the nitrogen-containing compound exhibits efficient catalytic decomposition and metal chelation at low concentrations, avoiding the potential metal corrosion risk from excessive introduction; third, the nitrogen-containing compound forms a dense protective film within this range to regulate morphology; the surfactant concentration reaches above the critical micelle concentration to ensure excellent dispersion and anti-re-adsorption capabilities while avoiding foam residue; and the amount of pH buffer is sufficient to maintain a constant pH value throughout the cleaning process. This formulation ensures that the cleaning agent maintains high residue removal rate, low surface roughness, and low metal contamination under a wide range of process conditions, demonstrating the good feasibility and stability of this invention.

[0031] This invention also provides a method for preparing a cleaning agent for CMP polishing, comprising the following steps: adding a first nitrogen-containing compound, a second nitrogen-containing compound, a third nitrogen-containing compound, a surfactant, and a pH buffer sequentially to deionized water according to a specified ratio; stirring at 20-30°C until completely dissolved; and adjusting the pH value to obtain the cleaning agent for CMP polishing. This invention does not have a specific limitation on the order of addition of the first nitrogen-containing compound, the second nitrogen-containing compound, the third nitrogen-containing compound, the surfactant, and the pH buffer; this invention avoids the degradation of heat-sensitive components (such as ACES or cage-like diamines) that may occur due to high temperatures by using room temperature (20-30°C), and ensures that each component gradually forms a pre-assembled complex structure during dissolution, preventing precipitation due to excessively high local concentrations; the final step of adjusting the pH value ensures that the buffer system is formed in the final state, maximizing the retention of the chemical activity of each component, thereby obtaining the target cleaning agent.

[0032] The present invention preferably performs microfiltration before using the cleaning agent to remove any particulate matter that may be present; the microfiltration process requires passing through a 0.1~0.2μm filter membrane.

[0033] This invention provides an application of a CMP polishing cleaning agent or a CMP polishing cleaning agent prepared by the above method in chemical mechanical polishing. The semiconductor substrate is cleaned using the above CMP polishing cleaning agent to reduce residue on the surface of the semiconductor substrate with silicon-silicon bonds after polishing.

[0034] In this invention, the semiconductor substrate includes an amorphous silicon substrate, a polycrystalline silicon substrate, or a monocrystalline silicon substrate.

[0035] This invention explicitly limits the cleaning application to amorphous silicon, polycrystalline silicon, or monocrystalline silicon substrates with silicon-silicon bonds. It utilizes the characteristics of these materials, such as numerous dangling bonds, high chemical activity, and a more negative zeta potential, which allows the amine components in the cleaning agent to be more effectively adsorbed and exert their effects. At the same time, the synergy between hexamethylenetetramine and pH buffers can effectively inhibit excessive etching of these highly active silicon surfaces. Thus, while thoroughly removing contaminants, it perfectly maintains the integrity of the gate oxide layer and the surface smoothness required for channel mobility.

[0036] In this invention, the cleaning process includes: 1) Contact: The cleaning agent is brought into full contact with the surface of the semiconductor substrate after the CMP process is completed; the semiconductor substrate includes amorphous silicon and / or polycrystalline silicon substrates.

[0037] 2) Cleaning: During contact, mechanical energy is provided by rotating PVA brushes, ultrasonic oscillation, or the friction between the substrate's own rotation and the polishing pad to assist the cleaning agent in removing contaminants.

[0038] 3) Rinsing: Rinse the substrate surface thoroughly with plenty of deionized water to remove loose contaminants and residual cleaning agent.

[0039] 4) Drying: Use isopropanol vapor drying or rotary drying to obtain a clean and dry substrate.

[0040] In this invention, the cleaning method can be applied to rinsing and grinding processes or independent cleaning processes.

[0041] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0042] Example 1

[0043] Weigh 0.5% of 2-aminoethanol and 0.3% of 3-amino-1,2-propanediol as the first nitrogen-containing compound; weigh 0.1% of triethylenediamine as the second nitrogen-containing compound; weigh 0.2% of hexamethylenetetramine as the third nitrogen-containing compound; weigh 0.05% of cocamidopropyl betaine as a surfactant; and weigh 0.2% of N-carbamoylmethylethanesulfonic acid as a pH buffer.

[0044] At room temperature of 25°C, the above components were added sequentially to the calculated amount of deionized water, and the mixture was stirred with a magnetic stirrer for 15 minutes until completely dissolved. Then, ammonia was added dropwise, and the pH of the solution was precisely adjusted to 9.0 using a pH meter. The solution was then filtered through a 0.2 μm polyethersulfone (PES) filter membrane to obtain the cleaning agent for CMP polishing in this embodiment.

[0045] A 300mm silicon wafer with a 2000 Å thick amorphous silicon film deposited on its surface was used as the grinding object. Chemical mechanical polishing (CMP) was performed using a polishing slurry containing colloidal silica (35nm particle size). After CMP treatment, the wafer was directly rinsed and ground on a grinding machine using a cleaning agent under the following conditions: grinding pressure 1.0 psi, grinding disc speed 83 rpm, cleaning agent supply rate 300 mL / min, and treatment time 60 s. After treatment, the wafer was brushed with 0.3% ammonia solution for 30 s, then rinsed with deionized water for 20 s, and dried to obtain sample E1.

[0046] Performance evaluation of sample E1: Test results showed that the total number of residues (>40nm) on the surface of sample E1 was only 3, including 1 abrasive particle residue (SiO2) and 2 organic residues; the surface roughness (RMS) was 0.12nm. Metal contamination detection showed that the contents of Fe and Cu were both below 1.0×10⁻⁶. 9 atoms / cm 2 (Detection limit).

[0047] Example 2

[0048] Weigh 0.06% of 2-aminoethanol and 0.04% of 3-amino-1,2-propanediol as the first nitrogen-containing compound; weigh 0.1% of triethylenediamine as the second nitrogen-containing compound; weigh 0.2% of hexamethylenetetramine as the third nitrogen-containing compound; weigh 0.05% of cocamidopropyl betaine as a surfactant; and weigh 0.2% of N-carbamoylmethylethanesulfonic acid as a pH buffer.

[0049] At room temperature of 25°C, the above components were added sequentially to the calculated amount of deionized water, and the mixture was stirred with a magnetic stirrer for 15 minutes until completely dissolved. Then, ammonia was added dropwise, and the pH of the solution was precisely adjusted to 9.0 using a pH meter. The solution was then filtered through a 0.2 μm polyethersulfone (PES) filter membrane to obtain the cleaning agent for CMP polishing in this embodiment.

[0050] A 300mm silicon wafer with a 2000Å thick amorphous silicon film deposited on its surface was used as the grinding object. Chemical mechanical polishing (CMP) was performed using a polishing slurry containing colloidal silica (35nm particle size). After CMP treatment, the wafer was directly rinsed and ground on a grinding machine using a cleaning agent under the following conditions: grinding pressure 1.0psi, grinding disc speed 83rpm, cleaning agent supply rate 300mL / min, and treatment time 60s. After treatment, the wafer was brushed with 0.3% ammonia solution for 30s, then rinsed with deionized water for 20s, and dried to obtain sample E2.

[0051] Performance evaluation of sample E2: Test results showed that the total number of residues (>40nm) on the surface of sample E2 was 8, including 4 abrasive particle residues (SiO2) and 4 organic residues; the surface roughness (RMS) was 0.14nm. Metal contamination detection showed that the contents of Fe and Cu were both below 1.0×10⁻⁶. 9 atoms / cm 2 (Detection limit).

[0052] Example 3

[0053] Weigh 6.0% of 2-aminoethanol and 4.0% of 3-amino-1,2-propanediol as the first nitrogen-containing compound; weigh 0.1% of triethylenediamine as the second nitrogen-containing compound; weigh 0.2% of hexamethylenetetramine as the third nitrogen-containing compound; weigh 0.05% of cocamidopropyl betaine as a surfactant; and weigh 0.2% of N-carbamoylmethylethanesulfonic acid as a pH buffer.

[0054] At room temperature of 25°C, the above components were added sequentially to the calculated amount of deionized water, and the mixture was stirred with a magnetic stirrer for 15 minutes until completely dissolved. Then, ammonia was added dropwise, and the pH of the solution was precisely adjusted to 9.0 using a pH meter. The solution was then filtered through a 0.2 μm polyethersulfone (PES) filter membrane to obtain the cleaning agent for CMP polishing in this embodiment.

[0055] A 300mm silicon wafer with a 2000Å thick amorphous silicon film deposited on its surface was used as the grinding object. Chemical mechanical polishing (CMP) was performed using a polishing slurry containing colloidal silica (35nm particle size). After CMP treatment, the wafer was directly rinsed and ground on a grinding mill using a cleaning agent under the following conditions: grinding pressure 1.0psi, grinding disc speed 83rpm, cleaning agent supply rate 300mL / min, and treatment time 60s. After treatment, the wafer was brushed with 0.3% ammonia solution for 30s, then rinsed with deionized water for 20s, and dried to obtain sample E3.

[0056] Performance evaluation of sample E3: Test results showed that the total number of residues (>40nm) on the surface of sample E3 was 5, including 2 abrasive particle residues (SiO2) and 3 organic residues; the surface roughness (RMS) was 0.15nm. Metal contamination detection showed that the contents of Fe and Cu were both below 1.0×10⁻⁶. 9 atoms / cm 2 (Detection limit).

[0057] Example 4

[0058] Weigh 0.5% of 2-aminoethanol and 0.3% of 3-amino-1,2-propanediol as the first nitrogen-containing compound; weigh 0.05% of 1,5-diazabicyclo[4.3.0]non-5-ene as the second nitrogen-containing compound; weigh 0.2% of hexamethylenetetramine as the third nitrogen-containing compound; weigh 0.05% of cocamidopropyl betaine as a surfactant; and weigh 0.2% of N-carbamoylmethylethanesulfonic acid as a pH buffer.

[0059] At room temperature of 20°C, the above components were added sequentially to the calculated amount of deionized water and stirred with a magnetic stirrer for 15 minutes until completely dissolved. Then, ammonia was added dropwise while monitoring with a pH meter to precisely adjust the pH of the solution to 9.0. The solution was then filtered using a 0.2 μm polyethersulfone (PES) filter membrane to obtain the CMP polishing cleaning agent of this embodiment.

[0060] A 300mm silicon wafer with a 2000Å thick amorphous silicon film deposited on its surface was used as the grinding object. Chemical mechanical polishing (CMP) was performed using a polishing slurry containing colloidal silica (35nm particle size). After CMP treatment, the wafer was directly rinsed and ground on a grinding mill using a cleaning agent under the following conditions: grinding pressure 1.0psi, grinding disc speed 83rpm, cleaning agent supply rate 300mL / min, and treatment time 60s. After treatment, the wafer was brushed with 0.3% ammonia solution for 30s, then rinsed with deionized water for 20s, and dried to obtain sample E4.

[0061] Performance evaluation of sample E4: Test results showed that the total number of residues (>40nm) on the surface of sample E4 was 9, including 4 abrasive particle residues (SiO2) and 5 organic residues; the surface roughness (RMS) was 0.13nm. Metal contamination detection showed that the contents of Fe and Cu were both below 1.0×10⁻⁶. 9 atoms / cm 2 (Detection limit).

[0062] Example 5

[0063] Weigh 0.5% of 2-aminoethanol and 0.3% of 3-amino-1,2-propanediol as the first nitrogen-containing compound; weigh 0.1% of triethylenediamine as the second nitrogen-containing compound; weigh 0.2% of hexamethylenetetramine as the third nitrogen-containing compound; weigh 0.05% of cocamidopropyl betaine as the surfactant; and weigh 0.2% of N-(2-acetamido)-2-aminoethanesulfonic acid as the pH buffer.

[0064] At room temperature of 25°C, the above components were added sequentially to the calculated amount of deionized water and stirred with a magnetic stirrer for 15 minutes until completely dissolved. Acetic acid was then added dropwise while the pH of the solution was precisely adjusted to 6.0 using a pH meter. The solution was then filtered through a 0.2 μm polyethersulfone (PES) filter membrane to obtain the cleaning agent for CMP polishing in this embodiment.

[0065] A 300mm silicon wafer with a 2000Å thick amorphous silicon film deposited on its surface was used as the grinding object. Chemical mechanical polishing (CMP) was performed using a polishing slurry containing colloidal silica (35nm particle size). After CMP treatment, the wafer was directly rinsed and ground on a grinding mill using a cleaning agent under the following conditions: grinding pressure 1.0psi, grinding disc speed 83rpm, cleaning agent supply rate 300mL / min, and treatment time 60s. After treatment, the wafer was brushed with 0.3% ammonia solution for 30s, then rinsed with deionized water for 20s, and dried to obtain sample E5.

[0066] Performance evaluation of sample E5: Test results showed that the total number of residues (>40nm) on the surface of sample E5 was 7, including 3 abrasive particle residues (SiO2) and 4 organic residues. The surface micro-roughness (RMS) was measured to be 0.13nm. Metal contamination detection showed that the contents of Fe and Cu were both below 1.0×10⁻⁶. 9 atoms / cm 2 (Detection limit).

[0067] Comparative Example 1 Weigh 0.06% of polyvinylpyrrolidone as a nonionic polymer; weigh 0.10% of hexamethylenetetramine as a nitrogen-containing compound; do not add the first nitrogen-containing compound, the second nitrogen-containing compound, surfactants, or pH buffers.

[0068] At room temperature of 25°C, the above components were added to a calculated amount of deionized water and stirred for 15 minutes. Then, ammonia was added dropwise to adjust the pH to 9.2. The mixture was filtered through a 0.2 μm filter membrane to obtain the comparative CMP polishing cleaning agent CE1.

[0069] Using the same amorphous silicon substrate, CMP treatment, and rinsing and polishing conditions as in Example 1 (polishing pressure 1.0 psi, polishing disc speed 83 rpm, cleaning agent supply 300 mL / min, treatment time 60 s), the sample CE1 was obtained after brushing with 0.3% ammonia water for 30 s, rinsing with deionized water for 20 s, and drying.

[0070] Performance evaluation of sample CE1: Test results showed that the total number of residues (>40nm) on the surface of sample CE1 was 15, including 8 abrasive particle residues (SiO2) and 7 organic residues; the surface roughness (RMS) was 0.18nm. Metal contamination detection showed an Fe content of 5.2 × 10⁻⁶. 9 atoms / cm 2 The Cu content is 3.8 × 10⁻⁶. 9 atoms / cm 2 .

[0071] Comparative Example 2 Weigh 0.5% of 2-aminoethanol and 0.3% of 3-amino-1,2-propanediol as the first nitrogen-containing compound; do not add the second nitrogen-containing compound; weigh 0.2% of hexamethylenetetramine as the third nitrogen-containing compound; weigh 0.05% of cocamidopropyl betaine as the surfactant; weigh 0.2% of N-carbamoylmethylethanesulfonic acid as the pH buffer.

[0072] At room temperature of 25°C, the above components were added sequentially to the calculated amount of deionized water, stirred and mixed for 15 minutes, and the pH was adjusted to 9.0 with ammonia. After filtration, the comparative CMP polishing cleaning agent CE2 was obtained. The amorphous silicon substrate was treated with the same CMP and cleaning process as in Example 1 to obtain sample CE2.

[0073] Performance evaluation of sample CE2: Test results showed that the total number of residues (>40nm) on the surface of sample CE2 was 12, including 5 abrasive particle residues (SiO2) and 7 organic residues; the surface micro-roughness (RMS) was 0.16nm; metal contamination detection showed that the contents of Fe and Cu were both below 1.0×10⁻⁶. 9 atoms / cm 2 (Detection limit).

[0074] Comparative Example 3 Weigh 0.5% of 2-aminoethanol and 0.3% of 3-amino-1,2-propanediol as the first nitrogen-containing compound; weigh 0.1% of triethylenediamine as the second nitrogen-containing compound; weigh 0.2% of hexamethylenetetramine as the third nitrogen-containing compound; weigh 0.05% of cocamidopropyl betaine as the surfactant; do not add N-carbamoylmethylethanesulfonic acid.

[0075] At room temperature of 25°C, the above components were added sequentially to the calculated amount of deionized water and stirred for 15 minutes. The pH was then adjusted to 9.0 using ammonia water. After filtration, the comparative CMP polishing cleaning agent CE3 was obtained. The amorphous silicon substrate was treated with the same CMP and cleaning process as in Example 1 to obtain sample CE3.

[0076] Performance evaluation of sample CE3: Test results showed that the total number of residues (>40nm) on the surface of sample CE3 was 14, including 6 abrasive particle residues (SiO2) and 8 organic residues. The surface micro-roughness (RMS) was 0.19nm. Metal contamination detection showed that the contents of Fe and Cu were both below 1.0×10⁻⁶. 9 atoms / cm 2(Detection limit).

[0077] Comparative Example 4 A commercially available mainstream alkaline CMP post-cleaning agent (nominally applicable to the 28nm node) was selected, and cleaning was performed according to the process parameters recommended in its product manual: the cleaning agent was diluted to the working concentration (1:50), and cleaning was performed at room temperature using a brush-type cleaning machine for 60 seconds, followed by rinsing with deionized water for 30 seconds, and drying to obtain sample CE4; the same amorphous silicon substrate and CMP pretreatment were used as in Example 1.

[0078] Performance evaluation of sample CE4: Test results showed that the total number of residues (>40nm) on the surface of sample CE4 was 22, including 10 abrasive particle residues (SiO2) and 12 organic residues; the surface roughness (RMS) was 0.22nm. Metal contamination detection showed that the Fe content was 8.5×10⁻⁶. 9 atoms / cm 2 The Cu content is 6.2 × 10⁻⁶. 9 atoms / cm 2 .

[0079] Comparative Example 5 Weigh 0.8% of 2-aminoethanol as the first nitrogen-containing compound (use only one); weigh 0.1% of triethylenediamine as the second nitrogen-containing compound; weigh 0.2% of hexamethylenetetramine as the third nitrogen-containing compound; weigh 0.05% of cocamidopropyl betaine as the surfactant; and weigh 0.2% of N-carbamoylmethylethanesulfonic acid as the pH buffer.

[0080] At room temperature of 25°C, the above components were added sequentially to the calculated amount of deionized water, stirred and mixed for 15 minutes, the pH was adjusted to 9.0 with ammonia, and filtered to obtain the comparative CMP polishing cleaning agent CE5. The amorphous silicon substrate was treated with the same CMP and cleaning process as in Example 1 to obtain sample CE5.

[0081] Performance evaluation of sample CE5: Test results showed that the total number of residues (>40nm) on the surface of sample CE5 was 11, including 5 abrasive particle residues (SiO2) and 6 organic residues; the surface roughness (RMS) was 0.15nm. Metal contamination detection showed that the contents of Fe and Cu were both below 1.0×10⁻⁶. 9 atoms / cm 2 (Detection limit).

[0082] Example 1 (E1) of this application exhibits the best performance in all indicators. In terms of residue removal, the total number of residues in Example 1 is only 1 / 5 of that in Comparative Example 1 and 1 / 6 of that in Comparative Example 4. For the difficult-to-remove grinding particle residue, Example 1 only detected 1 residue, while Comparative Examples 1 and 4 had as many as 8 and 10 residues, respectively. This further verifies the synergistic effect of the ternary synergistic system of "first nitrogen-containing compound + second nitrogen-containing compound + third nitrogen-containing compound" in this invention in disrupting particle adhesion and catalytically decomposing organic matrix.

[0083] As can be seen from Comparative Example 2, the lack of caged diamine led to a surge in the number of organic residues from 2 to 9, and a significant increase in metal contamination, indicating that caged diamine plays an irreplaceable key role in catalytic decomposition of complex organic matter and chelation of metal ions.

[0084] As shown in Comparative Example 3, the lack of pH buffer caused the surface roughness RMS to deteriorate from 0.12 nm to 0.21 nm. This indicates that in the absence of a high-performance zwitterionic buffer, local pH fluctuations during the cleaning process led to uneven etching of the silicon surface, verifying the core contribution of pH buffer in controlling surface morphology.

[0085] The data comparison between Examples 2 and 5 shows that even when the component concentration or pH value is at the boundary conditions, the performance indicators of the present invention are still significantly better than all comparative examples, which fully demonstrates that the technical solution of the present invention has a wide process window and excellent stability.

[0086] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A cleaning agent for CMP polishing, characterized in that, include First nitrogen-containing compound: at least two of the following compounds having one amine group and one or more hydroxyl groups and having a total number of carbon atoms of 1 to 6; The second nitrogen-containing compound: a cage-like diamine, wherein the cage-like diamine is selected from at least one of triethylenediamine, 1,5-diazabicyclo[4.3.0]non-5-ene and 1,8-diazabicyclo[5.4.0]undec-7-ene; The third nitrogen-containing compound: hexamethylenetetramine; Surfactants: alkyl betaine and / or sulfobetaine; pH buffer: N-carbamoylmethylethanesulfonic acid and / or N-(2-acetamido)-2-aminoethanesulfonic acid; The remainder is deionized water.

2. The cleaning agent for CMP polishing according to claim 1, characterized in that, The first nitrogen-containing compound includes at least two of 2-aminoethanol, 1-amino-2-propanol, 3-amino-1-propanol, ethanolamine, 2-(methylamino)ethanol, 2-amino-2-methyl-1-propanol, 1-dimethylamino-2-propanol, diethanolamine, triethanolamine, 3-amino-1,2-propanediol, 2-amino-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol, and 2-amino-2-ethyl-1,3-propanediol.

3. The cleaning agent for CMP polishing according to claim 1, characterized in that, The first nitrogen-containing compound is added at a rate of 0.1% to 10%; the second nitrogen-containing compound is added at a rate of 0.05% to 0.2%; the third nitrogen-containing compound is added at a rate of 0.1% to 0.5%; the surfactant is added at a rate of 0.01% to 0.2%; and the pH buffer is added at a rate of 0.05% to 0.5%.

4. The cleaning agent for CMP polishing according to claim 1, characterized in that, The alkyl betaine includes at least one of cocamidopropyl betaine, octamidopropyl betaine, and octyl / decamidopropyl betaine.

5. The cleaning agent for CMP polishing according to claim 4, characterized in that, The sulfobetaines include butyl octyl ether hydroxypropyl sulfobetaine and / or dodecyl hydroxypropyl sulfobetaine.

6. The cleaning agent for CMP polishing according to claim 1, characterized in that, The cleaning agent has a pH of 6 to 10.

5.

7. The cleaning agent for CMP polishing according to claim 1 or 6, characterized in that, The pH of the cleaning agent is controlled by a pH adjuster, which is selected from at least one of ammonia, acetic acid, and potassium hydroxide.

8. A method for preparing the CMP polishing cleaning agent according to any one of claims 1 to 7, comprising the following steps: adding a first nitrogen-containing compound, a second nitrogen-containing compound, a third nitrogen-containing compound, a surfactant and a pH buffer to deionized water in a specific ratio, stirring at 20 to 30°C until completely dissolved, and adjusting the pH value to obtain the CMP polishing cleaning agent.

9. The application of the CMP polishing cleaning agent according to any one of claims 1 to 7 or the CMP polishing cleaning agent prepared by the method of claim 8 in chemical mechanical polishing, characterized in that, The semiconductor substrate is cleaned using the aforementioned CMP polishing cleaning agent to reduce residue on the surface of the polished semiconductor substrate with silicon-silicon bonds.

10. The cleaning method according to claim 9, characterized in that, The semiconductor substrate includes an amorphous silicon substrate, a polycrystalline silicon substrate, or a monocrystalline silicon substrate.