Waterborne polyurethane composition, water-resistant cutting protection material, and preparation method and application of water-resistant cutting protection material

Abstract

The invention relates to a water-based polyurethane composition containing disulfide bonds, water-based polyurethane, a degradable water-resistant cutting protection material containing the water-based polyurethane composition as well as a preparation method and application of the degradable water-resistant cutting protection material, and the degradable water-resistant cutting protection material comprises the following components in parts by weight: 10-50 parts of water-based polyurethane containing disulfide bonds; 0.5 to 2 parts of a toughening agent; and 40 to 100 parts of deionized water. According to the invention, a transparent and smooth protective coating with a compact structure is spontaneously formed on the surface of the wafer by virtue of ester groups and carbamate groups with strong polarity in polyurethane molecules. The coating not only is optically transparent and beneficial to detection, but also has excellent adhesive force and water resistance, can be firmly combined with the surface of the wafer all the time in high-strength machining such as grinding and cutting, effectively resists impact and vibration of external force and scouring of cooling water, and protects precise circuits and microstructures on the surface of the wafer.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing processes, and particularly relates to an aqueous polyurethane composition, a water-resistant cutting protection material containing the same, and its preparation method and application. Background Technology

[0002] With the accelerated development of intelligent, connected, and electrified vehicles, automotive-grade chips, as core components of automotive electronic systems, are facing unprecedented reliability challenges. Unlike traditional consumer electronics chips, automotive-grade chips need to maintain stable operation for more than 15 years under harsh environments such as severe vibration, extreme temperature changes, and long-term mechanical stress impacts, which places extremely high reliability requirements on the chip manufacturing process.

[0003] Among numerous automotive-grade chips, CMOS image sensors (CIS) serve as the "visual perception core" of Advanced Driver Assistance Systems (ADAS) and autonomous vehicles, and their performance and reliability directly impact driving safety. Automotive-grade CIS chips not only need to meet stringent temperature cycling and mechanical shock tests, but also need to maintain stable optical performance under long-term vibration environments. Wafer dicing, as a crucial downstream process in chip manufacturing, directly affects the chip's mechanical strength and reliability. Despite the continuous development of new technologies such as laser cutting, die-cutting remains the mainstream dicing method for automotive-grade chips due to its mature technology, controllable cost, and applicability to various materials.

[0004] During the dicing process, continuous spraying of ultrapure water is required for cooling and debris washing. However, this process presents significant technical challenges. For example, patent CN114369416A discloses a thin-film encapsulation cutting protective tape with pre-reserved dicing grooves. To achieve good water washability, its main resin is a polyacrylic acid resin grafted or block-modified with reversible photoresponsive groups, containing a high proportion of hydrophilic groups in its molecular structure. However, during the cutting process, when subjected to continuous impact and immersion by the cutting cooling water, the protective film is prone to water absorption and swelling, and even partial dissolution, leading to the failure of its protective function. Patent CN111630113B discloses a method for preparing a hydrophobic protective coating for wafer dicing, whose main components include silane-modified polyurethane, polar organic solvents, leveling agents, and adhesion promoters. Although it can resist water erosion, subsequent removal requires strong chemical reagents or organic solvents, which not only increases environmental pressure but may also damage the chip surface.

[0005] Due to the trace metal debris generated during the cutting process (such as Fe from the cutter wheel) 3+ / Cr 3+ and Cu in the chip wiring layer 2+ / Al 3+ ).literature The paper "Electrochemical Metallic Ion Migration Property of Multi-Layer Ceramic Capacitor for Car Electronics" clearly states that under certain conditions, metal ions can migrate and form conductive dendrites between electrodes, ultimately leading to a decrease in insulation resistance and even short-circuit failure. Therefore, when cutting fluid and metal debris provide an ion source and electrolyte environment for electrochemical corrosion, the resulting ion migration will undoubtedly cause more fundamental damage to the reliability of the chip itself. This is a serious risk that must be strictly prevented for automotive-grade chips.

[0006] As can be seen from the above, most existing protective fluid systems do not specifically consider corrosion inhibition, making it difficult to meet the extremely high reliability requirements of automotive-grade chips. Therefore, developing a cutting protection material that can resist the erosion of cutting cooling water, is easy to remove in subsequent processes, and has corrosion inhibition capabilities has become an urgent need in the field of automotive-grade chip manufacturing.

[0007] To address the aforementioned technical bottlenecks, this invention proposes a water-resistant cutting protection material based on disulfide dynamic covalent bonds. Through molecular structure design, disulfide bonds (-SS-) and specific hydrophilic functional groups are introduced into the polyurethane backbone, achieving three innovative functions: First, the dynamic cross-linking network formed by disulfide bonds ensures the protective film maintains stable water resistance during cutting, effectively resisting erosion and dissolution by cooling water; second, after cutting, the disulfide bonds can be broken by a neutral cleaning solution containing a reducing agent, causing the cross-linked polymer to degrade into water-soluble fragments, achieving gentle and efficient removal; simultaneously, the specific functional groups in the material can form a self-passivating anti-corrosion barrier on the chip metal surface, inhibiting electrochemical corrosion.

[0008] This innovative design successfully resolves the contradiction between durability of protection, corrosion inhibition, and environmental removability in existing technologies, providing key technical support for the high-reliability manufacturing of automotive-grade chips. Summary of the Invention

[0009] The technical problem solved by this invention is the damage caused to automotive-grade chips by cutting protective materials during the cutting process, and the difficulty in removing general water-resistant protective coatings.

[0010] In view of the technical problems existing in the prior art, the present invention designs a water-resistant cutting protection material containing an aqueous polyurethane composition, which protects the precision structure of the ultrathin wafer surface during the cutting process (preventing physical damage and chemical corrosion) and can be removed by water-based cleaning agents.

[0011] It should be noted that, in this invention, unless otherwise specified, the specific meaning of "comprising" in relation to composition definition and description includes both open-ended meanings such as "comprising," "including," etc., and closed-ended meanings such as "composed of," etc., and similar meanings.

[0012] To solve the aforementioned technical problems, the present invention adopts the following solution:

[0013] [The first technical solution]

[0014] An aqueous polyurethane composition, characterized in that it comprises the following components:

[0015] Polyester diol, dibutyltin dilaurate, diisocyanate, chain extender and neutralizer;

[0016] The mass ratio of the polyester diol, dibutyltin dilaurate, chain extender, and diisocyanate is 2.5-4:0.0015-0.01:0.34-0.55:1.

[0017] The mass ratio of the neutralizing agent to the diisocyanate is 0.1-0.3:1;

[0018] The chain extender includes disulfide bond chain extenders, carboxylic acid hydrophilic chain extenders, and sulfonate chain extenders.

[0019] The mass ratio of the disulfide bond-containing chain extender, the carboxylic acid-type hydrophilic chain extender, and the sulfonate-grafted chain extender is 0.015-0.1:0.2-0.4:0.05-0.24.

[0020] The polyester diol is one or more of polyethylene adipate, polybutylene adipate, polyhexyl adipate, and polycaprolactone.

[0021] The diisocyanate is one or more of toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and diphenylmethane diisocyanate;

[0022] The neutralizing agent is triethanolamine and / or ammonia;

[0023] The disulfide-containing chain extender is one or more of 2,2'-diaminodiphenyl disulfide, 4,4'-diaminodiphenyl disulfide, 2,2'-dithiodiethylamine, bis(3-aminopropyl)disulfide, 2,2'-dithiodiethanol, and bis(4-hydroxybutyl)disulfide.

[0024] The carboxylic acid type hydrophilic chain extender is one or both of 2,2-dimethylolpropionic acid and 2,2-dimethylolbutyric acid.

[0025] The chain extender containing sulfonate is one or two of BY-3306, BY3305, and Poly-EPS.

[0026] [Second Technical Solution]

[0027] A method for preparing the above-mentioned waterborne polyurethane composition includes the following steps:

[0028] Polyurethane prepolymer is formed by polymerizing polyester diol and diisocyanate in the waterborne polyurethane composition as polymer raw materials and dibutyltin dilaurate as catalyst. Then, chain extenders are added to the polyurethane prepolymer under different conditions to extend the chain. After the reaction is completed, neutralizers are added under different conditions to re-mix and obtain the final product.

[0029] Furthermore, the preparation method of the above-mentioned waterborne polyurethane composition includes the following steps:

[0030] Step 1: Under a nitrogen atmosphere, polyester diol, dibutyltin dilaurate and diisocyanate are added to the reactor and reacted at 70-75℃ for 3-4 hours to obtain polyurethane prepolymer.

[0031] Step 2: Cool the obtained polyurethane prepolymer to 40-60℃, add a chain extender containing disulfide bonds, a carboxylic acid hydrophilic chain extender, and a chain extender containing sulfonate, and continue stirring for 2-3 hours until the reaction is complete. After the reaction is complete, lower the temperature to below 40℃, then add a neutralizing agent and stir for 10-30 minutes to neutralize, and obtain a waterborne polyurethane containing disulfide bonds.

[0032] Further, the mass ratio of the polyester diol, dibutyltin dilaurate, chain extender, and diisocyanate is 2.5-4:0.0015-0.01:0.34-0.55:1;

[0033] The mass ratio of the neutralizing agent to the diisocyanate is 0.1-0.3:1.

[0034] Furthermore, the chain extender includes a disulfide bond chain extender, a carboxylic acid hydrophilic chain extender, and a sulfonate chain extender, wherein the mass ratio of the disulfide bond chain extender, the carboxylic acid hydrophilic chain extender, and the sulfonate chain extender is 0.015-0.1:0.2-0.4:0.05-0.24.

[0035] Furthermore, in step 1, the molecular weight of the polyester diol is 500-3000.

[0036] Furthermore, in step 1, the molecular weight of the polyester diol is preferably 500-2000.

[0037] Furthermore, in step 1, the molecular weight of the polyester diol is preferably 1000-2000.

[0038] Further, in step 1, the diisocyanate is one or more of toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and diphenylmethane diisocyanate, preferably one or two of isophorone diisocyanate and dicyclohexylmethane diisocyanate.

[0039] Further, the chain extender containing disulfide bonds in step 2 is one or more of 2,2'-diaminodiphenyl disulfide, 4,4'-diaminodiphenyl disulfide, 2,2'-dithiodiethylamine, bis(3-aminopropyl)disulfide, 2,2'-dithiodiethanol, and bis(4-hydroxybutyl)disulfide, preferably one or two of 2,2'-dithiodiethylamine and 2,2'-dithiodiethanol.

[0040] Further, in step 2, the carboxylic acid type hydrophilic chain extender is 2,2-dimethylolpropionic acid and / or 2,2-dimethylolbutyric acid, preferably 2,2-dimethylolpropionic acid.

[0041] Furthermore, in step 2, the chain extender containing sulfonate is one or two of BY-3306, BY3305, and Poly-EPS, preferably BY-3306.

[0042] Furthermore, the neutralizing agent in step 3 is preferably triethanolamine.

[0043] [The third technical solution]

[0044] A biodegradable, water-resistant cut protection material, characterized in that it comprises the following components by weight:

[0045] 10-50 parts of the aqueous polyurethane containing disulfide bonds;

[0046] Toughening agent 0.5-2 parts;

[0047] 40-100 parts deionized water;

[0048] The waterborne polyurethane containing disulfide bonds is prepared by the above method.

[0049] Furthermore, the toughening agent is a carboxylated multi-walled carbon nanotube.

[0050] Furthermore, the toughening agent has a diameter (D) of 5-50 nm and a length (L) of 0.5-30 μm.

[0051] In this invention, in order to further optimize the performance of the biodegradable water-resistant cut protection material, the components can be optimized, including 25-35 parts of waterborne polyurethane containing disulfide bonds; 0.5-1 part of toughening agent; and 60-90 parts of deionized water.

[0052] In this invention, the toughening agent preferably has a diameter of 5-30 nm and a length of 1-15 μm.

[0053] In this invention, the toughening agent is more preferably 10-20 nm in diameter and more preferably 1-5 μm in length.

[0054] [Fourth technical solution]

[0055] A method for preparing the above-mentioned biodegradable water-resistant cut protection material includes the following steps:

[0056] The waterborne polyurethane containing disulfide bonds is dispersed with deionized water under high-speed stirring, and then a toughening agent is added and mixed evenly to obtain the biodegradable water-resistant cut protection material.

[0057] Furthermore, the high-speed stirring speed is 800-1200 rpm, and the stirring time is 1-2 hours.

[0058] [Fifth technical solution]

[0059] A method of using the above-mentioned biodegradable, water-resistant cut protection material includes the following steps:

[0060] The biodegradable, water-resistant cutting protective material is dropped onto the wafer surface and rotated at a speed of 500-1500 r / min for 60-180 s to obtain a protective film.

[0061] [Sixth Technical Solution]

[0062] The application of the aforementioned biodegradable, water-resistant cutting protective material in the field of automotive-grade CIS chip cutting wheel.

[0063] Furthermore, the aforementioned biodegradable water-resistant cutting protection material can be used in the cutting process of automotive-grade CIS chips. Its purpose is to provide a temporary protective film with strong water resistance and high adhesion to the wafer surface in a continuous water-spraying cutting environment, thereby effectively preventing the cooling water and cutting debris from eroding and contaminating the chip's sensitive circuit structure, ensuring cutting yield and product reliability.

[0064] [Seventh Technical Solution]

[0065] A cleaning solution for the above-mentioned biodegradable, water-resistant cutting protective material is characterized by comprising, by weight, the following components:

[0066] 1-5 parts reducing agent;

[0067] 1-10 parts of surfactant;

[0068] 70-100 parts of ultrapure water.

[0069] Furthermore, the reducing agent is one or more of the following: dithiothreitol, β-mercaptoethanol, tris(2-carboxyethyl)phosphine hydrochloride, glutathione, polyethylene glycol-mercapto, sodium sulfite, triphenylphosphine, and tributylphosphine.

[0070] Furthermore, the surfactant is one or more of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, sodium stearate, lauric acid soap, alkyl sulfonate, alkyl sulfate, and alkylbenzene sulfonate.

[0071] In this invention, in order to further optimize the performance of the cleaning solution for the biodegradable water-resistant cutting protective material, the components can be optimized, including 3-5 parts of reducing agent, 1-5 parts of surfactant, and 70-95 parts of ultrapure water.

[0072] In this invention, the reducing agent is preferably one or more of dithiothreitol, β-mercaptoethanol, and glutathione.

[0073] In this invention, the surfactant is preferably one or more of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and sodium stearate.

[0074] [Eighth Technical Solution]

[0075] A method for preparing the above-mentioned biodegradable, water-resistant cutting protective material cleaning solution includes the following steps:

[0076] Under continuous stirring, ultrapure water, reducing agent, and surfactant are added to the container and stirred at room temperature for 1-2 hours. After thorough mixing, the degradable water-resistant cutting protection material cleaning solution is obtained.

[0077] [Ninth Technical Solution]

[0078] A method for using the above-mentioned biodegradable, water-resistant cutting protection material cleaning solution includes the following steps:

[0079] Step 1: Apply the cleaning agent evenly to the wafer surface and let it stand for 10-30 minutes;

[0080] Step 2: Transfer the ultrathin wafer to the spray area and rinse away the cleaning solution on the front side of the ultrathin wafer with ultrapure water;

[0081] Step 3: Transfer the ultrathin wafer to the cleaning machine and rotate it at a speed of 1000-1500 r / min for 120-360s, while spraying ultrapure water onto the surface of the ultrathin wafer at a flow rate of 400-600 mL / min.

[0082] Step 4: Spin dry at 1500-2000 r / min for 120-360 seconds;

[0083] Step 5: Transfer the cleaned ultrathin wafer to the next process.

[0084] [The Tenth Technical Solution]

[0085] The application of the above-mentioned biodegradable, water-resistant cutting protective material cleaning solution in the field of automotive-grade CIS chip cutting wheel.

[0086] Furthermore, the biodegradable, water-resistant cutting protective material cleaning solution is used in the post-cutting process of automotive-grade CIS chips. The water-based, mild cleaning solution efficiently and thoroughly removes the protective film, achieving zero-residue cleanliness on the chip surface. This application directly solves the problems of high cleaning costs, heavy environmental impact, and potential damage to chip reliability caused by traditional processes relying on organic solvents or strong chemical reagents for stripping. It provides a cleaning solution for automotive-grade chips that meets both high cleanliness requirements and aligns with green manufacturing trends.

[0087] This invention provides a waterborne polyurethane, a biodegradable, water-resistant cut protection material containing the same, and a method for its preparation and application, which have the following beneficial effects:

[0088] 1. Formation of a high-adhesion and water-resistant protective coating. The protective solution uses water as a solvent. After application, it evaporates with the water, spontaneously forming a transparent, smooth, and dense protective coating on the wafer surface due to the highly polar ester and urethane groups in the polyurethane molecules. This coating is not only optically transparent for easy inspection but also possesses excellent adhesion and water resistance. It maintains a strong bond with the wafer surface during high-intensity machining processes such as grinding and cutting, effectively resisting external impacts, vibrations, and the erosion of cooling water, protecting the precision circuits and microstructures on the wafer surface.

[0089] 2. Dynamic Stress Dissipation Mechanism of Disulfide Bonds. The disulfide bonds (-SS-) in the protective coating act as dynamic, reversible covalent bonds, providing a unique mechanical protection mechanism for the wafer. During the dicing process, when the coating is subjected to mechanical stress, the disulfide bonds can undergo reversible breakage and recombination. Through slippage between molecular chains and energy dissipation, approximately 60% of the impact energy is effectively absorbed and dispersed. This mechanism significantly alleviates stress transmission to the ultrathin wafer surface, substantially reduces the generation and propagation of microcracks at the wafer edge, thereby controlling the dicing fragmentation rate to an extremely low level.

[0090] 3. Sulfonate group self-healing, passivation, and corrosion prevention mechanism. Sulfonate groups (-SO3) - Through a dual mechanism of electrostatic attraction and metal coordination, a dense and stable passivation and corrosion protection barrier is constructed on the wafer surface: its high-density negative charge can preferentially capture Fe. 3+ Cu 2 +Metal ions are bridged to form a continuous protective layer. This process simultaneously benefits from the rigid support of the disulfide cross-linked structure in the polyurethane network and the synergistic enhancement of the toughening agent, resulting in high density and low ion permeability of the coating. Furthermore, this mechanism possesses responsive self-healing capabilities: when cutting vibrations cause localized film damage, surrounding sulfonic acid groups can rapidly migrate and adsorb onto the newly exposed metal surface, rebuilding the passivation barrier and achieving continuous active corrosion suppression throughout the wafer dicing process.

[0091] 4. Environmentally friendly water-based cleaning and targeted degradation mechanism. The matching cleaning agent is an environmentally friendly system based on water and containing specific reducing agents and surfactants: the reducing agent can specifically break the disulfide bonds in the polyurethane backbone, reducing them to hydrophilic thiol groups (-SH) or thiosulfate groups, which significantly enhances the hydrophilicity of degradation products and promotes the disintegration of the cross-linked network into low molecular weight fragments; the surfactant synergistically enhances the wetting and penetration ability of the cleaning solution on coating residues, quickly penetrates into the coating-wafer interface, and completely removes the protective film; the entire cleaning process does not require strong acids, strong alkalis or organic solvents, the conditions are mild, there are zero VOC emissions, and the risk of secondary damage and environmental pollution is eliminated.

[0092] In summary, this invention systematically solves the core challenges in ultra-thin wafer processing, such as protective integrity, stress buffering, corrosion control, and environmentally friendly removal, through an integrated molecular design of "dynamic protection, active corrosion prevention, and green cleaning." It is particularly suitable for advanced processes of wafers with a thickness of 150-200μm and below, and has significant technological advantages and potential for large-scale industrial application. Attached Figure Description

[0093] Figure 1 : The infrared spectrum of the waterborne polyurethane-1 containing disulfide bonds in Example 1;

[0094] Figure 2 Photograph of the wafer after it has been immersed in the blue film for 1 hour in Example 9;

[0095] Figure 3 : Photographs of adhesion test results in Example 1;

[0096] Figure 4 : Photographs of the adhesion test for Comparative Example 1;

[0097] Figure 5 : A microscope image magnified 1170 times of the chip surface after it was coated with the protective material of Example 2 and cleaned with the material of Example 9;

[0098] Figure 6 : A microscope image magnified 1170 times of the chip surface after it was coated with the protective material of Comparative Example 7 and cleaned with Example 9. Detailed Implementation

[0099] The present invention will be further described below with reference to specific embodiments and accompanying drawings:

[0100] In this invention, Examples 1-8 and Comparative Examples 1-4 disclose various cutting protection materials, and the cleaning solution for the protection materials obtained in Examples 9-16, the components and mass ratios of which are shown in Tables 1 and 2.

[0101] Table 1. Components and proportions of cutting protective materials for Examples 1-8 and Comparative Examples 1-4

[0102] In Table 1 above, D represents the diameter and L represents the length.

[0103] The synthesis method of the waterborne polyurethane-1 containing disulfide bonds in Example 1 is as follows:

[0104] Step 1: Under a nitrogen atmosphere, 3.2 parts by mass of polyethylene adipate (molecular weight 1500), 0.05 parts by mass of dibutyltin dilaurate and 1 part by mass of isophorone diisocyanate were added to the reactor and reacted at 75°C for 4 hours to obtain a polyurethane prepolymer.

[0105] Step 2: Cool the polyurethane prepolymer obtained in Step 1 to 40°C, then add 0.042 parts by weight of 2,2'-dithiodiethylamine, 0.3 parts by weight of 2,2-dimethylolpropionic acid, and 0.13 parts by weight of sulfonate chain extender BY-3306 in sequence, and continue stirring for 2 hours until the reaction is complete to obtain the polymer.

[0106] Step 3: Lower the temperature of the polymer obtained in Step 2 to 35°C, add 0.2 parts by mass of triethanolamine and stir for 30 minutes to obtain waterborne polyurethane-1 containing disulfide bonds.

[0107] The synthesis method of the waterborne polyurethane-2 containing disulfide bonds in Example 2 is as follows:

[0108] Step 1: Under a nitrogen atmosphere, 2 parts by mass of polybutylene adipate (molecular weight 2000), 0.0025 parts by mass of dibutyltin dilaurate and 0.5 parts by mass of dicyclohexylmethane diisocyanate were added to the reactor and reacted at 75°C for 4 hours to obtain a polyurethane prepolymer.

[0109] Step 2: Cool the polyurethane prepolymer obtained in Step 1 to 40°C, and add 0.025 parts by weight of 2,2'-dithiodiethanol, 0.2 parts by weight of 2,2-dimethylolpropionic acid, and 0.05 parts by weight of sulfonate chain extender BY-3306 in sequence. Continue stirring for 2 hours until the reaction is complete to obtain the polymer.

[0110] Step 3: Lower the temperature of the polymer obtained in Step 2 to 35°C, add 0.1 parts by mass of triethanolamine and stir for 30 minutes to obtain waterborne polyurethane-2 containing disulfide bonds.

[0111] The synthesis method of the waterborne polyurethane-3 containing disulfide bonds in Example 3 is as follows:

[0112] Step 1: Under a nitrogen atmosphere, 3.75 parts by mass of polyhexyl adipate (molecular weight 1000), 0.0075 parts by mass of dibutyltin dilaurate and 1.5 parts by mass of toluene diisocyanate were added to the reactor and reacted at 75°C for 4 hours to obtain a polyurethane prepolymer.

[0113] Step 2: Cool the polyurethane prepolymer obtained in Step 1 to 40°C, and add 0.068 parts by weight of bis(3-aminopropyl) disulfide, 0.4 parts by weight of 2,2-dimethylolpropionic acid, and 0.24 parts by weight of sulfonate chain extender BY-3306 in sequence. Continue stirring for 2 hours until the reaction is complete to obtain the polymer.

[0114] Step 3: Lower the temperature of the polymer obtained in Step 2 to 35°C, add 0.3 parts by mass of triethanolamine and stir for 30 minutes to obtain waterborne polyurethane-3 containing disulfide bonds.

[0115] The synthesis method of the waterborne polyurethane-4 containing disulfide bonds in Example 4 is as follows:

[0116] Step 1: Under a nitrogen atmosphere, 3.6 parts by mass of polycaprolactone (molecular weight 500), 0.012 parts by mass of dibutyltin dilaurate and 1.2 parts by mass of hexamethylene diisocyanate were added to the reactor and reacted at 75°C for 4 hours to obtain a polyurethane prepolymer.

[0117] Step 2: Cool the polyurethane prepolymer obtained in Step 1 to 40°C, then add 0.1 parts by weight of bis(4-hydroxybutyl) disulfide, 0.3 parts by weight of 2,2-dimethylolpropionic acid, and 0.16 parts by weight of sulfonate chain extender BY3305 in sequence, and continue stirring for 2 hours until the reaction is complete to obtain the polymer.

[0118] Step 3: Lower the temperature of the polymer obtained in Step 2 to 35°C, add 0.24 parts by mass of triethanolamine and stir for 30 minutes to obtain waterborne polyurethane-4 containing disulfide bonds.

[0119] The synthesis method of the waterborne polyurethane-5 containing disulfide bonds in Example 5 is as follows:

[0120] Step 1: Under a nitrogen atmosphere, 6 parts by mass of polycaprolactone (molecular weight 3000), 0.003 parts by mass of dibutyltin dilaurate and 2 parts by mass of diphenylmethane diisocyanate were added to the reactor and reacted at 75°C for 4 hours to obtain polyurethane prepolymer.

[0121] Step 2: Cool the polyurethane prepolymer obtained in Step 1 to 40°C, and add 0.04 parts by weight of 2,2'-diaminodiphenyl disulfide, 0.4 parts by weight of 2,2-dihydroxymethylbutyric acid and 0.24 parts by weight of sulfonate chain extender BY3305 in sequence. Continue stirring for 2 hours until the reaction is complete to obtain the polymer.

[0122] Step 3: Lower the temperature of the polymer obtained in Step 2 to 35°C, add 0.4 parts by mass of triethanolamine and stir for 30 minutes to obtain waterborne polyurethane-5 containing disulfide bonds.

[0123] The synthesis method of the waterborne polyurethane-6 containing disulfide bonds in Example 6 is as follows:

[0124] Step 1: Under a nitrogen atmosphere, 3 parts by mass of polyethylene adipate (molecular weight 3000), 0.015 parts by mass of dibutyltin dilaurate and 1 part by mass of isophorone diisocyanate were added to the reactor and reacted at 75°C for 4 hours to obtain a polyurethane prepolymer.

[0125] Step 2: Cool the polyurethane prepolymer obtained in Step 1 to 40°C, and add 0.06 parts by weight of 4,4'-diaminodiphenyl disulfide, 0.28 parts by weight of 2,2-dihydroxymethylbutyric acid, and 0.12 parts by weight of Poly-EPS chain extender containing sulfonate in sequence. Continue stirring for 2 hours until the reaction is complete to obtain the polymer.

[0126] Step 3: Lower the temperature of the polymer obtained in Step 2 to 35°C, add 0.1 parts by mass of triethanolamine and stir for 30 minutes to obtain waterborne polyurethane-6 containing disulfide bonds.

[0127] The synthesis method of the waterborne polyurethane-7 containing disulfide bonds in Example 7 is as follows:

[0128] Step 1: Under a nitrogen atmosphere, 3.5 parts by mass of polyethylene adipate (molecular weight 1500), 0.01 parts by mass of dibutyltin dilaurate and 1 part by mass of isophorone diisocyanate were added to the reactor and reacted at 75°C for 4 hours to obtain polyurethane prepolymer.

[0129] Step 2: Cool the polyurethane prepolymer obtained in Step 1 to 40°C, and add 0.015 parts by weight of 2,2'-dithiodiethylamine, 0.32 parts by weight of 2,2-dimethylolpropionic acid, and 0.14 parts by weight of sulfonate chain extender BY-3306 in sequence. Continue stirring for 2 hours until the reaction is complete to obtain the polymer.

[0130] Step 3: Lower the temperature of the polymer obtained in Step 2 to 35°C, add 0.3 parts by mass of triethanolamine and stir for 30 minutes to obtain waterborne polyurethane-7 containing disulfide bonds.

[0131] The synthesis method of the waterborne polyurethane-8 containing disulfide bonds in Example 8 is as follows:

[0132] Step 1: Under a nitrogen atmosphere, 3.2 parts by mass of polyethylene adipate (molecular weight 1500), 0.05 parts by mass of dibutyltin dilaurate and 1 part by mass of isophorone diisocyanate were added to the reactor and reacted at 75°C for 4 hours to obtain a polyurethane prepolymer.

[0133] Step 2: Cool the polyurethane prepolymer obtained in Step 1 to 40°C, and add 0.2 parts by weight of 2,2'-dithiodiethylamine, 0.2 parts by weight of 2,2-dimethylolpropionic acid, and 0.072 parts by weight of sulfonate chain extender BY-3306 in sequence. Continue stirring for 2 hours until the reaction is complete to obtain the polymer.

[0134] Step 3: Lower the temperature of the polymer obtained in Step 2 to 35°C, add 0.25 parts by mass of triethanolamine and stir for 30 minutes to obtain waterborne polyurethane-8 containing disulfide bonds.

[0135] The synthesis method of polyurethane-D1 in Comparative Example 1 is as follows:

[0136] Step 1: Under a nitrogen atmosphere, 3.2 parts by mass of polyethylene adipate (molecular weight 1500), 0.05 parts by mass of dibutyltin dilaurate and 1 part by mass of isophorone diisocyanate were added to the reactor and reacted at 75°C for 4 hours to obtain a polyurethane prepolymer.

[0137] Step 2: Cool the polyurethane prepolymer obtained in Step 1 to 40°C, add 0.33 parts by weight of 2,2-dimethylolpropionic acid and 0.142 parts by weight of chain extender BY-3306 containing sulfonate in sequence, and continue stirring for 2 hours until the reaction is complete to obtain the polymer.

[0138] Step 3: Lower the temperature of the polymer obtained in Step 2 to 35°C, add 0.2 parts by mass of triethanolamine and stir for 30 minutes to obtain polyurethane-D1.

[0139] The synthesis method of polyurethane-D2 in Comparative Example 2 is as follows:

[0140] Step 1: Under a nitrogen atmosphere, 3.2 parts by mass of polyethylene adipate (molecular weight 1500), 0.05 parts by mass of dibutyltin dilaurate and 1 part by mass of isophorone diisocyanate were added to the reactor and reacted at 75°C for 4 hours to obtain a polyurethane prepolymer.

[0141] Step 2: Cool the polyurethane prepolymer obtained in Step 1 to 40°C, and add 0.58 parts by weight of 2,2'-dithiodiethylamine and 0.414 parts by weight of 2,2-dimethylolpropionic acid in sequence. Continue stirring for 2 hours until the reaction is complete to obtain the polymer.

[0142] Step 3: Lower the temperature of the polymer obtained in Step 2 to 35°C, add 0.2 parts by mass of triethanolamine and stir for 30 minutes to obtain polyurethane-D2.

[0143] The synthesis method of polyurethane-D3 in Comparative Example 3 is as follows:

[0144] Step 1: Under a nitrogen atmosphere, 3.2 parts by mass of polyethylene adipate (molecular weight 1500), 0.05 parts by mass of dibutyltin dilaurate and 1 part by mass of isophorone diisocyanate were added to the reactor and reacted at 75°C for 4 hours to obtain a polyurethane prepolymer.

[0145] Step 2: Cool the polyurethane prepolymer obtained in Step 1 to 40°C, add 0.112 parts by weight of 2,2'-dithiodiethylamine and 0.36 parts by weight of chain extender BY-3306 containing sulfonate in sequence, and continue stirring for 2 hours until the reaction is complete to obtain the polymer;

[0146] Step 3: Lower the temperature of the polymer obtained in Step 2 to 35°C, add 0.2 parts by mass of triethanolamine and stir for 30 minutes to obtain polyurethane-D3.

[0147] The synthesis method of polyurethane-D4 in Comparative Example 4 is as follows:

[0148] Step 1: Under a nitrogen atmosphere, 3.2 parts by mass of polyethylene adipate (molecular weight 1500), 0.005 parts by mass of dibutyltin dilaurate and 1 part by mass of isophorone diisocyanate were added to the reactor and reacted at 75°C for 4 hours to obtain a polyurethane prepolymer.

[0149] Step 2: Cool the polyurethane prepolymer obtained in Step 1 to 40°C, add 0.472 parts by weight of 2,2-dihydroxyethyl disulfide, and continue stirring for 2 hours until the reaction is complete to obtain the polymer;

[0150] Step 3: Lower the temperature of the polymer obtained in Step 2 to 35°C, add 0.2 parts by mass of triethanolamine and stir for 30 minutes to obtain polyurethane-D4.

[0151] Table 2. Components and proportions of the cleaning solutions for the protective materials obtained in Examples 9-16

[0152] The preparation method of the biodegradable, water-resistant cut protection material of this invention is as follows:

[0153] The waterborne polyurethane containing disulfide bonds was dispersed with deionized water under high-speed stirring at 1200 rpm for 2 hours to obtain the biodegradable water-resistant cutting protection material.

[0154] The method of using the biodegradable, water-resistant cut protection material of this invention is as follows:

[0155] The biodegradable, water-resistant cutting protective material is dropped onto the wafer surface and rotated at 1000 r / min for 120 s to obtain a protective film.

[0156] The preparation method of the biodegradable, water-resistant cutting protective material cleaning solution of the present invention is as follows:

[0157] Under continuous stirring, ultrapure water, reducing agent, and surfactant are added to the container and stirred at room temperature for 1 hour. After thorough mixing, the degradable water-resistant cutting protection material cleaning solution is obtained.

[0158] The method of using the biodegradable, water-resistant cutting protection material cleaning solution of the present invention is as follows:

[0159] Step 1: Apply the cleaning agent evenly to the wafer surface and let it stand for 15 minutes;

[0160] Step 2: Transfer the ultrathin wafer to the spray area and rinse away the cleaning solution on the front side of the ultrathin wafer with ultrapure water;

[0161] Step 3: Transfer the ultrathin wafer to the cleaning machine and rotate it at a speed of 1000 r / min for 1360 s, while spraying ultrapure water onto the surface of the ultrathin wafer at a flow rate of 500 mL / min.

[0162] Step 4: Spin dry at 1500 rpm for 180 seconds;

[0163] Step 5: Transfer the cleaned ultrathin wafer to the next process.

[0164] Regarding performance testing and explanation:

[0165] The test method for blue film resistance in performance 1 is as follows:

[0166] The blue film was immersed in the cleaning solution of the protective material obtained in Examples 9-16 for 1 hour, and the appearance and adhesion of the blue film were observed after immersion. If there was no significant change in the appearance and adhesion of the blue film, it indicated that the cleaning agent did not damage the blue film.

[0167] The adhesion test method for performance 2 is as follows:

[0168] The protective materials obtained from Examples 1-8 and Comparative Examples 1-4 were spin-coated onto a dummy sheet and cured. The dummy sheet was then cut into 3mm*2mm pieces using an ultrathin wafer dicing machine. During the cutting process, water was sprayed onto the cutting wheel to cool it down. After the cutting was completed, the dummy sheet was spin-dried. If the protective film on the dummy sheet did not fall off, it indicates that its adhesion met the requirements.

[0169] The test method for the cleaning performance of the film layer is as follows:

[0170] In a static Class 100 cleanroom, the protective materials obtained in Examples 1-8 and Comparative Examples 1-4 were spin-coated onto the chip. Then, the chip was cleaned using the protective material cleaning solution of Example 9 according to the cleaning process. Finally, the film residue was observed under a microscope at 1170x magnification.

[0171] The performance test results of the cleaning solutions for the protective materials obtained in Examples 1-8 and Comparative Examples 1-4, and the protective materials obtained in Examples 9-16 are shown in Tables 3 and 4.

[0172] Table 3 Test data for protective materials

[0173] Table 4 Test data for cleaning solution of protective materials

[0174] Analysis and explanation of the test results:

[0175] As can be seen from the test data in Table 3, the polyurethane film prepared using the specific combination of chain extenders provided by this invention exhibits both excellent adhesion (no peeling) and good cleanability. This indicates that the carboxylic acid-type hydrophilic chain extender, the sulfonate-containing chain extender, and the disulfide bond-containing chain extender produce a significant synergistic effect in the system of this invention, successfully solving the technical problem that traditional materials struggle to achieve both strong adhesion and environmentally friendly removability. Comparative examples 1-4 show that each of the three chain extenders plays a crucial and indispensable role; the absence or imbalance of any one of them will lead to failure in one aspect of adhesion or cleaning effect.

[0176] As can be seen from the test data in Table 4, the cleaning agent containing reducing agent and surfactant provided by the present invention can completely clean the protective film provided by the present invention, and is relatively gentle, without damaging the blue film during the cleaning process.

[0177] In a static Class 100 cleanroom, the protective material obtained in Example 1 was spin-coated onto the chip. The protective material cleaning solutions of Comparative Examples 5-7 were used to clean the chip according to the cleaning process. When the membrane residue was observed under a microscope at 1170x magnification, it was observed that Comparative Example 5 lacked a reducing agent and Comparative Example 7 used only ultrapure water, so neither could clean the membrane layer. Comparative Example 6 lacked a surfactant, and a small amount of residue remained after cleaning.

[0178] Further comparison can be made using the accompanying diagrams in the instruction manual:

[0179] Figure 1 The infrared spectrum of the aqueous polyurethane-1 containing disulfide bonds in Example 1 is shown below. Figure 2 A photograph of the wafer after it has been immersed in the blue film for 1 hour in Example 9; Figure 3 Photographs of the adhesion test in Example 1;

[0180] Figure 4 Photographs of the adhesion test for Comparative Example 1; Figure 5 A microscope image magnified 1170 times of the chip surface after being coated with Example 2 and cleaned with Example 9; Figure 6 Microscopic photograph of the chip surface after being coated with the protective material of Comparative Example 7 and cleaned with Example 9, magnified 1170 times.

[0181] from Figure 1 It can be seen that 3315cm -1 The peak at 1726 cm⁻¹ represents the stretching vibration peak of NH₃ in -NHCOO₃⁻. -1 and 1035cm -1 The peak at 1305 cm⁻¹ represents the stretching vibration peaks of C=O and CO. -1 and 1237 cm -1 The characteristic peak at this location corresponds to the S=O stretching vibration of the sulfonic acid group, proving that the sulfonic acid group was successfully introduced into the polyurethane system. From... Figure 2 It can be seen that the cleaning agent of the present invention is relatively mild and will not damage the blue film. From Figure 3 As can be seen from the adhesion test, the coating on the Dummy sheet coated with the protective liquid did not peel off. Figure 4 As can be seen, the coating on the comparative Dummy sheet peeled off significantly after the adhesion test. Figure 5 It can be seen that there is no film residue on the chip surface, indicating that the protective solution has good cleaning properties. Figure 6 It can be seen that after cleaning, there is a lot of film residue on the chip surface.

[0182] The present invention has been described above by way of example with reference to the embodiments and accompanying drawings. Obviously, the implementation of the present invention is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A waterborne polyurethane composition, characterized in that, It includes the following components: Polyester diol, dibutyltin dilaurate, diisocyanate, chain extender and neutralizer; The mass ratio of the polyester diol, dibutyltin dilaurate, chain extender, and diisocyanate is 2.5-4:0.0015-0.01:0.34-0.55:

1. The mass ratio of the neutralizing agent to the diisocyanate is 0.1-0.3:1; The chain extender includes disulfide bond chain extenders, carboxylic acid hydrophilic chain extenders, and sulfonate chain extenders.

2. The waterborne polyurethane composition according to claim 1, characterized in that: The mass ratio of the disulfide bond-containing chain extender, the carboxylic acid-type hydrophilic chain extender, and the sulfonate-containing chain extender is 0.015-0.1:0.2-0.4:0.05-0.

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3. The waterborne polyurethane composition according to claim 1, characterized in that: The polyester diol is one or more of polyethylene adipate, polybutylene adipate, polyhexyl adipate, and polycaprolactone. The diisocyanate is one or more of toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and diphenylmethane diisocyanate; The neutralizing agent is triethanolamine and / or ammonia; The disulfide-containing chain extender is one or more of 2,2'-diaminodiphenyl disulfide, 4,4'-diaminodiphenyl disulfide, 2,2'-dithiodiethylamine, bis(3-aminopropyl)disulfide, 2,2'-dithiodiethanol, and bis(4-hydroxybutyl)disulfide. The carboxylic acid type hydrophilic chain extender is 2,2-dihydroxymethylpropionic acid and / or 2,2-dihydroxymethylbutyric acid.

4. A method for preparing the waterborne polyurethane composition according to any one of claims 1-3, characterized in that: Polyurethane prepolymer is formed by polymerizing polyester diol and diisocyanate in the waterborne polyurethane composition as polymer raw materials and dibutyltin dilaurate as catalyst. Then, chain extenders are added to the polyurethane prepolymer under different conditions to extend the chain. After the reaction is completed, neutralizers are added under different conditions to re-mix and obtain the final product.

5. The method for preparing the waterborne polyurethane composition according to claim 4, characterized in that, Includes the following steps: Step 1: Under an inert atmosphere, polyester diol, dibutyltin dilaurate and diisocyanate are reacted at 70-75℃ for 3-4 hours to obtain polyurethane prepolymer. Step 2: Cool the obtained polyurethane prepolymer to 40-60℃, add the chain extender and continue stirring for 2-3 hours. After the reaction is complete, lower the temperature to below 40℃, then add the neutralizing agent and stir for 10-30 minutes to neutralize, thus obtaining waterborne polyurethane containing disulfide bonds.

6. A water-resistant cutting protection material, characterized in that, Based on parts by weight, it includes the following components: 10-50 parts of waterborne polyurethane containing disulfide bonds; Toughening agent 0.5-2 parts; 40-100 parts deionized water; The waterborne polyurethane containing disulfide bonds is prepared by the method described in claim 4 or 5.

7. The water-resistant cutting protection material according to claim 6, characterized in that: The toughening agent is a carboxylated multi-walled carbon nanotube.

8. A method for preparing the water-resistant cutting protective material according to claim 6 or 7, characterized in that, Includes the following steps: The waterborne polyurethane containing disulfide bonds is dispersed with deionized water under high-speed stirring, and then a toughening agent is added and mixed evenly to obtain the biodegradable water-resistant cut protection material.

9. A method of using the water-resistant cutting protective material according to claim 6 or 7, characterized in that, Includes the following steps: The biodegradable, water-resistant cutting protective material is dropped onto the wafer surface and rotated at a speed of 500-1500 r / min for 60-180 s to obtain a protective film.

10. The use of the water-resistant cutting protective material according to claim 6 or 7 in the field of automotive-grade CIS chip cutting wheel.

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