Wafer cutting protection liquid for laser-assisted plasma etching process and preparation method and application thereof

Abstract

The present application relates to a kind of wafer cutting protection fluid for laser-assisted plasma etching process and its preparation method and application, according to weight parts, the wafer cutting protection fluid includes: water-soluble furan-based polyamide resin 70~85 parts;Solvent 15~25 parts;Plasticizer 1~5 parts;Ultraviolet light absorber 0.1~1 parts;Leveling agent 0.1~1 parts.The wafer cutting protection fluid provided by the present application can form a protective film with excellent mechanical properties, wear resistance and heat resistance, and easy to clean, widely used in thin wafer processing, deep silicon etching and TSV through hole and other processing processes.

Description

Technical Field

[0001] This invention relates to the field of semiconductor processing technology, specifically to a wafer cutting protective solution for laser-assisted plasma etching processes, its preparation method, and its application. Background Technology

[0002] Currently, semiconductor wafer manufacturing is developing towards miniaturization, multi-chip stacking, and ultra-thinning. After processes such as back-side grinding, thinning, and etching, these semiconductor wafers need to be divided into individual chips through a dicing process.

[0003] In existing research, the most advanced semiconductor wafer dicing technology is hybrid laser scribing and plasma dicing. The specific operation involves: irradiating specific locations on the semiconductor wafer with a laser of a certain wavelength, causing the laser to interact with the material and form a certain number of processing grooves; then transferring the wafer to a plasma-enhanced cavity for physical and chemical etching. This dicing method can selectively dice chips, even with curved scribing lines. In recent years, due to its extremely high etching rate, this dicing method has been widely considered one of the best choices for chip dicing.

[0004] For example, US20160365283A1 discloses an etch-resistant water-soluble mask for hybrid wafer dicing using laser scribing and plasma etching, comprising an ultraviolet light absorbing compound, polyvinyl alcohol resin, and a solvent. The water-soluble mask is baked to increase its etch resistance. After baking, the water-soluble mask is patterned using a laser scribing process to form gaps. Finally, plasma etching is performed to separate the integrated circuit.

[0005] CN113039628A discloses a protective film forming agent for plasma cutting and a method for manufacturing a semiconductor chip, which includes a water-soluble resin (polyvinylpyrrolidone), a light absorber, and a solvent. The protective film for plasma cutting can form a processing groove of a desired shape by laser irradiation.

[0006] However, most existing plasma cutting protective fluids use water-soluble resins with poor heat resistance, such as polyvinylpyrrolidone (PVP) or polyvinyl alcohol (PVA). Furthermore, most water-soluble resins do not have high resistance to plasma etching, while resins with good etching resistance are usually difficult to dissolve in water.

[0007] Therefore, there is an urgent need to develop a high-performance wafer cutting protective liquid for laser-assisted plasma etching processes, so that the protective film has the characteristics of high temperature resistance, plasma etching resistance, uniform coating and easy water washing, while meeting the requirements of green economy and low cost. Summary of the Invention

[0008] To address the above problems, the present invention aims to provide a wafer dicing protective fluid for laser-assisted plasma etching processes, its preparation method, and its application. Compared with the prior art, the wafer dicing protective fluid provided by the present invention can form a protective film with excellent mechanical properties, wear resistance, and heat resistance, and is easy to clean. It is widely applicable to thin wafer processing, deep silicon etching, and TSV via processing processes.

[0009] To achieve this objective, the present invention employs the following technical solution:

[0010] In a first aspect, the present invention provides a wafer dicing protective solution for laser-assisted plasma etching processes, wherein the wafer dicing protective solution comprises the following components by weight:

[0011]

[0012]

[0013] This invention utilizes a compound of water-soluble furan-based polyamide resin, solvent, plasticizer, ultraviolet absorber, and leveling agent to produce a wafer dicing protective solution that forms a protective film with excellent mechanical properties, wear resistance, and heat resistance, and is easy to clean. Furthermore, the materials are recyclable, offering advantages such as low cost and low carbon footprint. Specifically, the water-soluble furan-based polyamide resin used in this invention, compared to existing polyamide resins, not only exhibits extremely high solubility in aqueous solutions but also enhances the hardness and heat resistance of the protective film, resulting in a smoother and denser film that effectively avoids the adverse effects of high-energy lasers and plasma etching. On the other hand, the synergistic effect of the water-soluble furan-based polyamide resin and plasticizer addresses the issue of excessive rigidity in the resin, making the resulting protective film less prone to cracking under vacuum.

[0014] In this invention, the wafer dicing protective liquid, by weight, comprises: 70-85 parts of water-soluble furanyl polyamide resin, for example, 70, 72, 74, 76, 78, 80, 82, 84, or 85 parts; 15-25 parts of solvent, for example, 15, 16, 17, 18, 20, 22, or 25 parts; 1-5 parts of plasticizer, for example, 1, 2, 3, 4, or 5 parts; 0.1-1 part of ultraviolet absorber, for example, 0.1, 0.2, 0.4, 0.6, 0.8, or 1 part; and 0.1-1 part of leveling agent, for example, 0.1, 0.2, 0.4, 0.6, 0.8, or 1 part, but not limited to the listed values. Other unlisted values ​​within the range are also applicable. This invention optimizes the plasma erosion resistance and achieves the ideal hardness of the resulting protective film by controlling the weight ratio of water-soluble furan-based polyamide resin and plasticizer within a specific range. On the one hand, if the amount of water-soluble furan-based polyamide resin is too low, the resulting protective film will be too soft, and the coating will not provide sufficient rigidity and heat resistance, resulting in weak plasma etching resistance of the wafer. On the other hand, if the amount of water-soluble furan-based polyamide resin is too high, the protective film will be too rigid, making it prone to cracking during vacuum processing, which is detrimental to subsequent etching processes.

[0015] Preferably, the raw materials for preparing the water-soluble furan-based polyamide resin include: furan dicarboxylate, diamine compounds, and modifiers.

[0016] Preferably, the furanyl dicarboxylate includes dimethyl 2,5-furanyl dicarboxylate and / or diethyl 2,5-furanyl dicarboxylate.

[0017] Preferably, the diamine compound includes any one or a combination of at least two of the following: 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexamethylenediamine, 1,3-cyclohexanedimethylamine, 1,4-cyclohexanedimethylamine, furan-2,5-dimethyldimethylamine, or m-phenylenediamine.

[0018] Preferably, the modifier comprises sodium dimethyl 1,3-phthalate-5-sulfonate.

[0019] Preferably, the mass ratio of furan dicarboxylate to modifier is (3-4):(1-2), for example, it can be 3:1, 3:1.5, 3:2, 3.5:1, 3.5:1.5, 3.5:2, 4:1, 4:1.5 or 4:2, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] In this invention, by adding sodium dimethyl 1,3-phthalate-5-sulfonate as a modifier, the water solubility of furanyl polyamide resin can be further enhanced. Furthermore, by preferably controlling the mass ratio of difuranyl phthalate to the modifier within a specific range, the prepared resin can possess good water solubility. This invention, by preferably controlling the amount of modifier added, can increase the water solubility of the resin and improve the stability of the protective solution. When too much or too little modifier is added, the stability of the protective solution is easily reduced, leading to problems such as particle precipitation or stratification.

[0021] Preferably, the ratio of the total molar amount of the furan dicarboxylate and the modifier to the molar amount of the diamine compound is 1:(1.02 to 1.10), for example, it can be 1:1.02, 1:1.03, 1:1.04, 1:1.05, 1:1.06, 1:1.07, 1:1.08, 1:1.09 or 1:1.10, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] Preferably, the preparation method of the water-soluble furan-based polyamide resin includes: prepolymerizing furan dicarboxylate, diamine compound and modifier under the action of a catalyst, then heating to a first reaction temperature for a first reaction, then continuing to heat to a second reaction temperature for a second reaction, and finally vacuuming and cooling in sequence to obtain the resin.

[0023] In this invention, the final temperature of the cooling process is not specifically limited, but is generally controlled to be below 160°C before discharge and pelletizing.

[0024] Preferably, the method for preparing the water-soluble furanyl polyamide resin further includes: dissolving the resin in water and adjusting the pH value to obtain the water-soluble furanyl polyamide resin.

[0025] Preferably, the catalyst comprises any one or a combination of at least two of triethyl phosphate, titanium isopropoxide, tetrabutyl titanate, or titanium citrate.

[0026] In this invention, the titanium citrate in the catalyst is generally of ultrapure grade, i.e., purity ≥ 98%.

[0027] Preferably, the mass of the catalyst accounts for 1 to 3% of the total mass of furan dicarboxylate and diamine compounds, for example, it can be 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8% or 3%, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0028] Preferably, the prepolymerization reaction, the first reaction, and the second reaction are all carried out under a nitrogen atmosphere.

[0029] Preferably, the temperature of the prepolymerization reaction is 60 to 90°C, for example, 60°C, 62°C, 65°C, 68°C, 70°C, 72°C, 75°C, 78°C, 80°C, 82°C, 85°C, 88°C or 90°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Preferably, the prepolymerization reaction time is 1 to 3 hours, for example, it can be 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours or 3 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] Preferably, the first reaction temperature is 140 to 170°C, for example, it can be 140°C, 142°C, 145°C, 148°C, 150°C, 152°C, 155°C, 158°C, 160°C, 162°C, 165°C, 168°C or 170°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0032] Preferably, the reaction time is 1 to 3 hours, for example, 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours or 3 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] Preferably, the second reaction temperature is 200-230°C, for example, it can be 200°C, 202°C, 205°C, 208°C, 210°C, 212°C, 215°C, 218°C, 220°C, 222°C, 225°C, 228°C or 230°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0034] Preferably, the reaction time is 1 to 3 hours, for example, 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours or 3 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0035] Preferably, the final vacuum level of the vacuuming is 40 to 60 Pa, for example, it can be 40 Pa, 42 Pa, 45 Pa, 48 Pa, 50 Pa, 52 Pa, 55 Pa, 58 Pa or 60 Pa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0036] Preferably, the pH adjuster used for pH adjustment includes any one or a combination of at least two of lactic acid, citric acid, malic acid, tartaric acid, or fumaric acid.

[0037] Preferably, the endpoint pH value for pH adjustment is 5 to 7, for example, it can be 5, 5.2, 5.5, 5.8, 6, 6.2, 6.5, 6.8 or 7, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0038] Preferably, the viscosity of the water-soluble furanyl polyamide resin is 40 to 100 mPa·s, for example, it can be 40 mPa·s, 45 mPa·s, 50 mPa·s, 55 mPa·s, 60 mPa·s, 65 mPa·s, 70 mPa·s, 75 mPa·s, 80 mPa·s, 85 mPa·s, 90 mPa·s, 95 mPa·s or 100 mPa·s, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0039] Preferably, the solvent includes water and / or an organic solvent.

[0040] Preferably, the organic solvent includes any one or a combination of at least two of ethylene glycol, ethylene glycol tert-butyl ether, isopropanol, propylene glycol, propylene glycol monomethyl ether, ethylene glycol ethyl ether acetate, propylene glycol monomethyl ether acetate, n-butyl acetate, or dimethyl carbonate.

[0041] Preferably, when the solvent includes water and an organic solvent, the mass ratio of the organic solvent to water is (1-2):(3-4), for example, it can be 1:3, 1:3.5, 1:4, 1.5:3, 1.5:3.5, 1.5:4, 2:3, 2:3.5 or 2:4, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0042] Preferably, the plasticizer includes any one or a combination of at least two of sorbitol, xylitol, hydroxypropyl cellulose, or triethyl citrate.

[0043] Preferably, the ultraviolet absorber includes any one or a combination of at least two of sodium stilbene biphenyl disulfonate, disodium phenyl dibenzimidazole tetrasulfonate, or terephthalimide dicamphor sulfonate.

[0044] Preferably, the leveling agent comprises an acrylic polymer and / or an ester polymer.

[0045] In a second aspect, the present invention provides a method for preparing a wafer dicing protective solution for laser-assisted plasma etching process as described in the first aspect of the present invention, the preparation method comprising the following steps:

[0046] (1) Mix the solvent and ultraviolet absorber according to the formula and stir for the first time until the materials are completely dissolved to obtain a clear and transparent first mixed solution.

[0047] (2) According to the formula amount, mix the first mixed solution obtained in step (1), water-soluble furan-based polyamide resin, plasticizer and leveling agent, and stir for the second time until a clear and transparent second mixed solution is obtained. Then, discharge and filter in sequence to obtain wafer cutting protective liquid.

[0048] The preparation method provided by the present invention, through operations such as first stirring, second stirring, discharging, and filtration, can obtain a clear, transparent, and uniformly composed wafer dicing protective liquid.

[0049] In this invention, the first and second stirring are generally carried out in a stirring vessel, and the stirring vessel is temperature controlled by a circulating water system.

[0050] Preferably, the temperatures of the first stirring and the second stirring in step (1) are each independently 30 to 40°C, for example, 30°C, 32°C, 34°C, 36°C, 38°C or 40°C, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0051] Preferably, the rotation speed of the first stirring and the second stirring is independently 40 to 80 rpm, for example, it can be 40 rpm, 45 rpm, 50 rpm, 55 rpm, 60 rpm, 65 rpm, 70 rpm, 75 rpm or 80 rpm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0052] Preferably, the stirring time for the first stirring and the stirring time for the second stirring are each independently 5 to 10 hours, for example, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0053] Preferably, the filtration accuracy in step (2) is 50 to 100 nm, for example, it can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm or 100 nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0054] As a preferred embodiment of the second aspect of the present invention, the preparation method includes the following steps:

[0055] (1) According to the formula, mix the solvent and ultraviolet absorber and stir for 5 to 10 hours at a temperature of 30 to 40°C and a speed of 40 to 80 rpm until the materials are completely dissolved and a clear and transparent first mixed solution is obtained.

[0056] (2) According to the formula, the first mixed solution obtained in step (1), water-soluble furan-based polyamide resin, plasticizer and leveling agent are mixed and stirred for 5 to 10 hours at a temperature of 30 to 40°C and a speed of 40 to 80 rpm until a clear and transparent second mixed solution is obtained. Then, the mixture is discharged sequentially and filtered under a precision of 50 to 100 nm to obtain a wafer cutting protective liquid.

[0057] In a second aspect, the present invention provides an application of a wafer dicing protective solution as described in the first aspect of the present invention for a laser-assisted plasma etching process, the application comprising the following steps:

[0058] (a) A wafer dicing protective solution is applied to the surface of a semiconductor wafer and dried to form a protective film;

[0059] (b) Laser cutting is performed on a specified location of a semiconductor wafer containing the protective film described in step (a) to form a processing groove with a specific pattern on the surface of the semiconductor wafer;

[0060] (c) The semiconductor wafer containing the processing groove described in step (b) is subjected to plasma etching, and then cleaned, dried and tested in sequence to obtain the processed semiconductor wafer.

[0061] The wafer cutting protective fluid provided by this invention is used in the laser-assisted plasma etching process of semiconductor wafers. It can effectively solve the problems of large heat-affected zone in the processing tank after high-energy laser cutting, small selective etching ratio after plasma etching, chip damage, and cleaning residue. It is widely used in thin wafer processing, deep silicon etching, and TSV through-hole processing.

[0062] Preferably, the coating amount of the wafer dicing protective solution in step (a) is 10 to 15 mL / wafer, for example, it can be 10 mL / wafer, 11 mL / wafer, 12 mL / wafer, 13 mL / wafer, 14 mL / wafer or 15 mL / wafer, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0063] Preferably, the semiconductor wafer is 8 inches or 12 inches in size.

[0064] Preferably, the coating method includes spin coating.

[0065] Preferably, the spin coating speed is 1000-1500 rpm, for example, it can be 1000 rpm, 1100 rpm, 1200 rpm, 1300 rpm, 1400 rpm or 1500 rpm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0066] Preferably, the drying temperature is 60-80°C, for example, 60°C, 62°C, 65°C, 68°C, 70°C, 72°C, 75°C or 80°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0067] Preferably, the drying time is 4 to 10 minutes, for example, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes or 10 minutes, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0068] Preferably, the laser cutting rate in step (b) is 200-300 mm / s, for example, it can be 200 mm / s, 210 mm / s, 220 mm / s, 230 mm / s, 240 mm / s, 250 mm / s, 260 mm / s, 270 mm / s, 280 mm / s, 290 mm / s or 300 mm / s, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0069] Preferably, the power of the laser cutting is 1 to 2.5W, for example, it can be 1W, 1.2W, 1.4W, 1.6W, 1.8W, 2W, 2.2W, 2.4W or 2.5W, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0070] In this invention, the laser cutting generally uses ultraviolet light with a wavelength of 355nm.

[0071] In this invention, the plasma etching is a conventional method in the art, generally using fluorine-based gas for etching. The plasma etching adopts the Bosch process, that is, SF6 gas is introduced into the reaction chamber for physicochemical etching; then C4F8 gas is introduced into the reaction chamber for passivation to form a passivation layer; the etching and passivation are repeated to form a deep and narrow high aspect ratio structure on the wafer.

[0072] Preferably, the cleaning agent used in step (c) includes water, such as ultrapure water and / or deionized water.

[0073] Preferably, the drying temperature in step (c) is 60 to 80°C, for example, 60°C, 62°C, 65°C, 68°C, 70°C, 72°C, 75°C, 78°C or 80°C, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0074] Compared with the prior art, the present invention has the following beneficial effects:

[0075] (1) The wafer dicing protective fluid provided by the present invention is formulated by using water-soluble furan-based polyamide resin, solvent, plasticizer, ultraviolet light absorber and leveling agent. The resulting wafer dicing protective fluid can form a protective film with good mechanical properties, wear resistance and heat resistance, and is easy to clean. Furthermore, the above materials can be recycled and reused, and have the advantages of low cost and low carbon environmental protection. It is widely applicable to thin wafer processing, deep silicon etching and TSV through-hole processing.

[0076] (2) In the wafer cutting protective liquid provided by the present invention, the addition of water-soluble furan-based polyamide resin enhances the high temperature resistance and plasma etching resistance of the protective film. The water-soluble furan-based polyamide resin and plasticizer work together to solve the problem of excessive rigidity of the water-soluble furan-based polyamide resin, so that the resulting protective film is not easy to crack under vacuum.

[0077] (3) By controlling the preparation method of water-soluble furanyl polyamide resin in the wafer cutting protective liquid provided by the present invention, especially by controlling the addition of modifier, its solubility in aqueous solution can be increased, and the hardness and heat resistance of the protective film can be improved, making the protective film layer flat and dense and easy to clean.

[0078] (4) Under preferred conditions, the protective film obtained by the wafer dicing protective solution provided by the present invention has a surface TTV of less than 0.331 μm and a surface hardness of more than 3.56 MPa. 5％loss The temperature reaches above 380℃, no cracks are found in the vacuum film surface test, the heat-affected zone is below 1.92μm, the selected etching ratio is above 205, the number of 50nm particles is ≤10 after cleaning test, and no particle precipitation is found in storage test. Detailed Implementation

[0079] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0080] Preparation Example 1

[0081] This preparation example provides a method for preparing a water-soluble furanyl polyamide resin, the preparation method comprising the following steps:

[0082] (i) Under a nitrogen atmosphere, furan dicarboxylate, diamine compounds and modifiers are loaded into a glass reactor equipped with a stirring and condensing device. Under the action of a catalyst, a prepolymerization reaction is carried out at 60°C for 3 hours. Then, the temperature is raised to 170°C for a first reaction for 2 hours. After that, the temperature is raised to 220°C for a second reaction for 2 hours. Finally, a vacuum is drawn for 1 hour until the final vacuum degree is 50 Pa. The temperature is then lowered to below 160°C and the material is discharged and pelletized to obtain resin.

[0083] (ii) The resin obtained in step (i) is dissolved in a solvent, i.e., deionized water, and the pH value is adjusted to 6.5 using citric acid to obtain a water-soluble furanyl polyamide resin with a viscosity of 90 mPa·s.

[0084] In this preparation example, the specific components and amounts of the furan dicarboxylate, diamine compound, modifier, catalyst, and deionized water are shown in Table 1.

[0085] Preparation Example 2

[0086] This preparation example provides a method for preparing a water-soluble furanyl polyamide resin, the preparation method comprising the following steps:

[0087] (i) Under a nitrogen atmosphere, furan dicarboxylate, diamine compounds and modifiers are loaded into a glass reactor equipped with a stirring and condensing device. Under the action of a catalyst, a prepolymerization reaction is carried out at 75°C for 2 hours. Then, the temperature is raised to 150°C for a first reaction for 1 hour. After that, the temperature is raised to 200°C for a second reaction for 3 hours. Finally, a vacuum is drawn for 1 hour until the final vacuum degree is 60 Pa. The temperature is then lowered to below 160°C and the material is discharged and pelletized to obtain resin.

[0088] (ii) The resin obtained in step (i) is dissolved in a solvent, i.e., deionized water, and the pH value is adjusted to 7 using citric acid to obtain a water-soluble furanyl polyamide resin with a viscosity of 100 mPa·s.

[0089] In this preparation example, the specific components and amounts of the furan dicarboxylate, diamine compound, modifier, catalyst, and deionized water are shown in Table 1.

[0090] Preparation Example 3

[0091] This preparation example provides a method for preparing a water-soluble furanyl polyamide resin, the preparation method comprising the following steps:

[0092] (i) Under a nitrogen atmosphere, furan dicarboxylate, diamine compounds and modifiers are loaded into a glass reactor equipped with a stirring and condensing device. Under the action of a catalyst, a prepolymerization reaction is carried out at 90°C for 1 hour. Then, the temperature is raised to 140°C for a first reaction for 3 hours. After that, the temperature is raised to 230°C for a second reaction for 1 hour. Finally, a vacuum is drawn for 1 hour until the final vacuum degree is 40 Pa. The temperature is then lowered to below 160°C and discharged for pelleting to obtain resin.

[0093] (ii) The resin obtained in step (i) is dissolved in a solvent, i.e., deionized water, and the pH value is adjusted to 5 using citric acid to obtain a water-soluble furanyl polyamide resin with a viscosity of 40 mPa·s.

[0094] In this preparation example, the specific components and amounts of the furan dicarboxylate, diamine compound, modifier, catalyst, and deionized water are shown in Table 1.

[0095] Preparation Examples 4-6

[0096] Preparation Examples 4-6 provide a method for preparing a water-soluble furan-based polyamide resin. Except for the specific components and amounts of furan dicarboxylate, diamine compound, modifier, catalyst and deionized water shown in Table 1, the preparation methods provided in Preparation Examples 4-6 are the same as those in Preparation Example 1.

[0097] Preparation Example 7

[0098] This preparation example provides a method for preparing a water-soluble furan-based polyamide resin. The difference between this preparation method and Preparation Example 1 is only in changing the amount of modifier used, so that the mass ratio of furan dicarboxylate to modifier in step (i) is 4.5:1.

[0099] The specific components and amounts of furan dicarboxylate, diamine compounds, modifiers, catalysts, and deionized water in this preparation example are shown in Table 1.

[0100] Preparation Example 8

[0101] This preparation example provides a method for preparing a water-soluble furan-based polyamide resin. The difference between this preparation method and Preparation Example 1 is only in changing the amount of modifier, so that the mass ratio of furan dicarboxylate to modifier in step (i) is 1:1.

[0102] The specific components and amounts of furan dicarboxylate, diamine compounds, modifiers, catalysts, and deionized water in this preparation example are shown in Table 1.

[0103] Comparative Preparation Example 1

[0104] This comparative preparation example provides a method for preparing a furanyl polyamide resin, the only difference between the preparation method and preparation example 1 is that no modifier is added in step (i).

[0105] The specific components and amounts of furan dicarboxylate, diamine compounds, modifiers, catalysts, and deionized water in this comparative preparation example are shown in Table 1.

[0106] Table 1

[0107]

[0108] In Table 1, " / " indicates that the component is not added.

[0109] Example 1

[0110] This embodiment provides a wafer dicing protective solution for laser-assisted plasma etching processes. The wafer dicing protective solution comprises a water-soluble furan-based polyamide resin, a solvent, a plasticizer, an ultraviolet light absorber, and a leveling agent. The water-soluble furan-based polyamide resin is obtained from Preparation Example 1. The names and amounts of each component of the wafer dicing protective solution in this embodiment are shown in Table 2.

[0111] This embodiment also provides a method for preparing the above-mentioned wafer dicing protective liquid, the preparation method comprising the following steps:

[0112] (1) According to the formula, mix the solvent and ultraviolet absorber in a stirring tank, turn on the circulating water system to control the temperature, and carry out the first stirring for 7 hours at a temperature of 35℃ and a speed of 60rpm until the material is completely dissolved and a clear and transparent first mixed solution is obtained.

[0113] (2) According to the formula amount, the first mixed solution obtained in step (1), water-soluble furan-based polyamide resin, plasticizer and leveling agent are mixed and stirred for 7 hours at a temperature of 35°C and a speed of 60 rpm until a clear and transparent second mixed solution is obtained. Then, the mixture is discharged sequentially and filtered under a precision of 70 nm to obtain a wafer cutting protective liquid.

[0114] Example 2

[0115] This embodiment provides a wafer dicing protective solution for laser-assisted plasma etching processes. The wafer dicing protective solution comprises a water-soluble furan-based polyamide resin, a solvent, a plasticizer, an ultraviolet light absorber, and a leveling agent. The water-soluble furan-based polyamide resin was obtained from Preparation Example 2. The names and amounts of each component of the wafer dicing protective solution in this embodiment are shown in Table 2.

[0116] This embodiment also provides a method for preparing the above-mentioned wafer dicing protective liquid, the preparation method comprising the following steps:

[0117] (1) According to the formula, mix the solvent and ultraviolet absorber in a stirring tank, turn on the circulating water system to control the temperature, and carry out the first stirring for 5 hours at a temperature of 30℃ and a speed of 80rpm until the material is completely dissolved and a clear and transparent first mixed solution is obtained.

[0118] (2) According to the formula amount, the first mixed solution obtained in step (1), water-soluble furan-based polyamide resin, plasticizer and leveling agent are mixed and stirred for 10 hours at a temperature of 40°C and a speed of 40 rpm until a clear and transparent second mixed solution is obtained. Then, the mixture is discharged sequentially and filtered under a precision of 50 nm to obtain a wafer cutting protective liquid.

[0119] Example 3

[0120] This embodiment provides a wafer dicing protective solution for laser-assisted plasma etching processes. The wafer dicing protective solution comprises a water-soluble furan-based polyamide resin, a solvent, a plasticizer, an ultraviolet light absorber, and a leveling agent. The water-soluble furan-based polyamide resin was obtained from Preparation Example 3. The names and amounts of each component of the wafer dicing protective solution in this embodiment are shown in Table 2.

[0121] This embodiment also provides a method for preparing the above-mentioned wafer dicing protective liquid, the preparation method comprising the following steps:

[0122] (1) According to the formula, mix the solvent and ultraviolet absorber in a stirring tank, turn on the circulating water system to control the temperature, and carry out the first stirring for 10 hours at a temperature of 40℃ and a speed of 40rpm until the material is completely dissolved and a clear and transparent first mixed solution is obtained.

[0123] (2) According to the formula amount, the first mixed solution obtained in step (1), water-soluble furan-based polyamide resin, plasticizer and leveling agent are mixed and stirred for 5 hours at a temperature of 30°C and a speed of 80 rpm until a clear and transparent second mixed solution is obtained. Then, the mixture is discharged sequentially and filtered under a precision of 100 nm to obtain a wafer cutting protective liquid.

[0124] Examples 4-6

[0125] Examples 4-6 provide wafer dicing protective solutions for laser-assisted plasma etching processes. The names and amounts of each component of the wafer dicing protective solution are shown in Table 2. The water-soluble furan-based polyamide resin is the water-soluble furan-based polyamide resin provided in Examples 4-6, and the preparation process is the same as in Example 1.

[0126] Examples 7-8

[0127] Examples 7-8 provide wafer dicing protective solutions for laser-assisted plasma etching processes. The only difference between these solutions and those in Example 1 is the use of the water-soluble furanyl polyamide resin provided in Examples 7-8. The names and amounts of each component in the wafer dicing protective solutions of Examples 7-8 are shown in Table 2.

[0128] Comparative Example 1

[0129] This comparative example provides a wafer dicing protective solution for laser-assisted plasma etching processes. The only difference between this wafer dicing protective solution and that of Example 1 is that the water-soluble furanyl polyamide resin is replaced with the furanyl polyamide resin obtained in Comparative Preparation Example 1. The names and amounts of each component of the wafer dicing protective solution in this comparative example are shown in Table 2.

[0130] Comparative Example 2

[0131] This comparative example provides a wafer dicing protective solution for laser-assisted plasma etching processes. The only difference between this wafer dicing protective solution and that of Example 1 is that the mass of the water-soluble furanyl polyamide resin is 6.5 kg. The names and amounts of each component of the wafer dicing protective solution in this comparative example are shown in Table 2.

[0132] Comparative Example 3

[0133] This comparative example provides a wafer dicing protective solution for laser-assisted plasma etching processes. The only difference between this wafer dicing protective solution and that of Example 1 is that the mass of the water-soluble furanyl polyamide resin is 9 kg. The names and amounts of each component of the wafer dicing protective solution in this comparative example are shown in Table 2.

[0134] Comparative Example 4

[0135] This comparative example provides a wafer dicing protective solution for laser-assisted plasma etching processes. The only difference between this wafer dicing protective solution and that of Example 1 is that the mass of the plasticizer is 0.05 kg. The names and amounts of each component of the wafer dicing protective solution in this comparative example are shown in Table 2.

[0136] Comparative Example 5

[0137] This comparative example provides a wafer dicing protective solution for laser-assisted plasma etching processes. The only difference between this wafer dicing protective solution and that of Example 1 is that the mass of the plasticizer is 0.8 kg. The names and amounts of each component of the wafer dicing protective solution in this comparative example are shown in Table 2.

[0138] Comparative Example 6

[0139] This comparative example provides a wafer dicing protective solution for laser-assisted plasma etching processes. The only difference between this wafer dicing protective solution and that of Example 1 is the absence of a plasticizer. The names and amounts of each component in the wafer dicing protective solution of this comparative example are shown in Table 2.

[0140] Comparative Example 7

[0141] This comparative example provides a wafer dicing protective solution for laser-assisted plasma etching processes. The only difference between the wafer dicing protective solution and Example 1 is that the water-soluble furanyl polyamide resin is replaced with a water-soluble polyamide resin. The only difference between the preparation method of the water-soluble polyamide resin and Example 1 is that dimethyl 2,5-furandicarboxylate is replaced with dimethyl terephthalate.

[0142] The names and amounts of each component of the wafer dicing protective fluid in this comparative example are shown in Table 2.

[0143] Table 2

[0144]

[0145]

[0146] In Table 2, " / " indicates that the component is not added.

[0147] Application Example 1

[0148] This application example provides an application of a wafer dicing protective solution for laser-assisted plasma etching processes. The wafer dicing protective solution is the one provided in Example 1, and the application includes the following steps:

[0149] (a) A wafer dicing protective solution is coated onto the surface of a 12-inch semiconductor wafer by spin coating at a speed of 1200 rpm and a coating amount of 12 mL / wafer. The wafer is then dried at 70°C for 6 min to form a protective film.

[0150] (b) Laser cutting is performed on a specified position of a semiconductor wafer containing the protective film described in step (a). The laser cutting uses 355nm ultraviolet light, the cutting rate is 250mm / s, and the power is 2W, so that a processing groove with a specific pattern is formed on the surface of the semiconductor wafer.

[0151] (c) The semiconductor wafer containing the processing trench described in step (b) is subjected to plasma etching. In the plasma etching, SF6 gas is first introduced into the reaction chamber for physicochemical etching, and then C4F8 gas is introduced into the reaction chamber for passivation to form a passivation layer. The etching and passivation are repeated to form a deep and narrow high aspect ratio structure on the wafer. Then, the wafer is cleaned with deionized water, dried at 70°C, and tested to obtain the processed semiconductor wafer.

[0152] Application Examples 2-8

[0153] Application Examples 2-8 provide an application of a wafer dicing protective solution for laser-assisted plasma etching processes. Except that the wafer dicing protective solutions are the wafer dicing protective solutions provided in Examples 1-8, the rest are the same as in Application Example 1.

[0154] Comparative Application Examples 1-7

[0155] Comparative Application Examples 1 to 7 provide an application of a wafer dicing protective solution for laser-assisted plasma etching processes. Except that the wafer dicing protective solutions are the wafer dicing protective solutions provided in Comparative Examples 1 to 7, the rest are the same as in Application Example 1.

[0156] Performance testing:

[0157] (1) Basic physical property tests, the results are shown in Table 3:

[0158] ①TTV of membrane surface: measured using Corning Flatmaster 200 flatness tester.

[0159] ② Film surface hardness: The test method provided in GB / T21838-2008 "Instrumented Indentation Test of Hardness and Material Parameters of Metallic Materials" was used for testing with a nanoindenter.

[0160] ③ Heat resistance: T was tested using a thermogravimetric analyzer. 5％loss That is, the temperature point at which the sample loses 5% of its weight.

[0161] ④ Vacuum film surface test: Taking a 12-inch wafer as an example, spin-coat the wafer cutting protective solution at a speed of 1000 rpm for 240 seconds, bake at 60℃ for 5 minutes, and then place it in a vacuum drying oven for 10 minutes. After taking it out, visually inspect and observe the film surface condition under a microscope.

[0162] (2) Laser cutting test results are shown in Table 3:

[0163] Heat-affected zone test: Pre-grooving condition test was conducted using SLG1E picosecond laser Dual Wide 1.5W 1pass and DOE Wide 11W 3pass, and the heat-affected zone was observed under a microscope.

[0164] (3) Plasma etching test results are shown in Table 3:

[0165] ① Silicon etching depth: Plasma dry etching experiments were conducted using the SPD1A etching machine PC2-test223 program (60 loops) to observe and measure the surface / section depth.

[0166] ② Select etching ratio: Select etching ratio = silicon etching depth / film consumption.

[0167] (4) Cleaning test results are shown in Table 3:

[0168] Taking a 12-inch wafer as an example, the wafer dicing protective solution is spin-coated at 1000 rpm for 240 seconds, then baked in a 150℃ oven for 120 minutes. After baking, the wafer is placed on a spin coater, and the film surface is wetted with ultrapure water for 1 minute. Spin coating is then started (at 1000 rpm). While spin coating, the wafer is rinsed with ultrapure water for 1 minute. After drying with nitrogen, the residual adhesive on the film surface is observed under a microscope, and the number of particles with a particle size >50nm is recorded.

[0169] (5) Storage test results are shown in Table 3:

[0170] The wafer dicing protective solution was sealed and placed in a 25°C constant temperature drying oven for one month, during which the condition of the solution was visually observed.

[0171] Table 3

[0172]

[0173]

[0174]

[0175] The following points can be observed from the data in Table 3:

[0176] (1) As can be seen from the data in Examples 1-6, the protective film obtained by the wafer dicing protective liquid provided by the present invention has a surface TTV of less than 0.331 μm and a surface hardness of more than 3.56 MPa. 5％loss The temperature reaches above 380℃, no cracks are found in the vacuum film surface test, the heat-affected zone is below 1.92μm, the etching ratio is selected to be above 205, the number of 50nm particles is ≤10 after cleaning test, and no particles are precipitated in the adhesive solution.

[0177] (2) As can be seen from the data of Examples 1, 7-8 and Comparative Example 1, the only difference between Examples 7-8 and Comparative Example 1 and Example 1 is that the mass ratio of furanyl dicarboxylate to modifier in the preparation of the water-soluble furanyl polyamide resin is not within the preferred range of the present invention and no modifier is added. The number of 50nm particles in Examples 7-8 and Comparative Example 1 is significantly increased, and the TTV of the film surface in Comparative Example 1 is increased and fine cracks appear. It can be seen that the present invention can reduce particle residue by adding a modifier and controlling the mass ratio of furanyl dicarboxylate to modifier in the preparation of water-soluble furanyl polyamide resin, while further ensuring the stability of the protective liquid and avoiding particle precipitation or stratification.

[0178] (3) From the data of Example 1, Comparative Examples 2-3, Comparative Examples 4-5 and Comparative Example 6, it can be seen that the difference between Comparative Examples 2-5 and Example 1 is only that the weight of water-soluble furan-based polyamide resin or plasticizer is not within the range controlled by the present invention. The difference of Comparative Example 6 is only that no plasticizer is added. The selective etching ratio in Comparative Examples 2-6 is significantly reduced. Fine cracks appear in Comparative Examples 1, 3, 4 and 6. The film surface TTV of Comparative Examples 1 and 5 is significantly increased. It can be seen that the present invention uses water-soluble furan-based polyamide resin and plasticizer to work together. The plasticizer can solve the problem of excessive rigidity of water-soluble furan-based polyamide resin, so that the resulting protective film is not easy to crack under vacuum, and the protective film has good heat resistance and hardness, improves plasma etching resistance, and thus ensures a high selective etching ratio.

[0179] (4) As can be seen from the data of Example 1 and Comparative Example 7, the only difference between Comparative Example 7 and Example 1 is that the water-soluble furanyl polyamide resin was replaced with a water-soluble polyamide resin. Compared with Comparative Example 7, the protective film obtained in Example 1 has higher heat resistance and hardness, a significantly smaller heat-affected zone, and a significantly improved selective etching ratio. Therefore, the water-soluble furanyl polyamide resin used in this invention, compared with existing polyamide resins, not only has extremely strong solubility in aqueous solution but also improves the hardness and heat resistance of the protective film, effectively avoiding the adverse effects of high-energy lasers and plasma etching.

[0180] In summary, the wafer dicing protective fluid provided by this invention can form a protective film with excellent mechanical properties, wear resistance, and heat resistance, and is easy to clean. It is widely applicable to thin wafer processing, deep silicon etching, and TSV via processing.

[0181] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A wafer dicing protective solution for laser-assisted plasma etching processes, characterized in that, The wafer dicing protective fluid comprises the following components in parts by weight: 70-80 parts of water-soluble furanyl polyamide resin; Solvent: 18-20 parts; Plasticizer 1-5 parts; 0.1 to 1 part of ultraviolet light absorber; Leveling agent 0.1~1 part; The raw materials for preparing the water-soluble furanyl polyamide resin include: furanyl dicarboxylate, diamine compounds, and modifiers; The furan dicarboxylate includes dimethyl 2,5-furan dicarboxylate and / or diethyl 2,5-furan dicarboxylate; The diamine compounds include any one or a combination of at least two of the following: 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexamethylenediamine, 1,3-cyclohexanedimethylamine, 1,4-cyclohexanedimethylamine, furan-2,5-dimethyldimethylamine, or m-phenylenediamine. The modifier includes sodium dimethyl 1,3-phthalate-5-sulfonate; The mass ratio of furan dicarboxylic acid diester to modifier is (3~4):(1~2).

2. The wafer dicing protective fluid according to claim 1, characterized in that, The ratio of the total molar amount of furan dicarboxylate and the modifier to the molar amount of the diamine compound is 1:(1.02~1.10).

3. The wafer dicing protective fluid according to claim 1, characterized in that, The preparation method of the water-soluble furan-based polyamide resin includes: Furan dicarboxylate, diamine compounds, and modifiers are prepolymerized under the action of a catalyst. Then, the temperature is raised to the first reaction temperature for the first reaction, and then the temperature is raised to the second reaction temperature for the second reaction. Finally, the mixture is vacuumed and cooled to obtain the resin.

4. The wafer dicing protective fluid according to claim 3, characterized in that, The method for preparing the water-soluble furanyl polyamide resin further includes: dissolving the resin in water and adjusting the pH value to obtain the water-soluble furanyl polyamide resin.

5. The wafer dicing protective fluid according to claim 3, characterized in that, The catalyst comprises any one or a combination of at least two of triethyl phosphate, titanium isopropoxide, tetrabutyl titanate, or titanium citrate.

6. The wafer dicing protective fluid according to claim 3, characterized in that, The catalyst accounts for 1-3% of the total mass of furan dicarboxylate and diamine compounds.

7. The wafer dicing protective fluid according to claim 3, characterized in that, The prepolymerization reaction, the first reaction, and the second reaction were all carried out under a nitrogen atmosphere.

8. The wafer dicing protective fluid according to claim 3, characterized in that, The temperature of the prepolymerization reaction is 60~90℃.

9. The wafer dicing protective fluid according to claim 3, characterized in that, The prepolymerization reaction takes 1 to 3 hours.

10. The wafer dicing protective fluid according to claim 3, characterized in that, The first reaction temperature is 140~170℃.

11. The wafer dicing protective fluid according to claim 3, characterized in that, The first reaction takes 1 to 3 hours.

12. The wafer dicing protective fluid according to claim 3, characterized in that, The second reaction temperature is 200~230℃.

13. The wafer dicing protective fluid according to claim 3, characterized in that, The second reaction takes 1 to 3 hours.

14. The wafer dicing protective fluid according to claim 3, characterized in that, The final vacuum level of the vacuuming process is 40~60 Pa.

15. The wafer dicing protective fluid according to claim 4, characterized in that, The pH adjuster used includes any one or a combination of at least two of lactic acid, citric acid, malic acid, tartaric acid, or fumaric acid.

16. The wafer dicing protective fluid according to claim 4, characterized in that, The endpoint pH value for the pH adjustment is 5-7.

17. The wafer dicing protective fluid according to claim 1, characterized in that, The viscosity of the water-soluble furanyl polyamide resin is 40~100 mPa·s.

18. The wafer dicing protective fluid according to claim 1, characterized in that, The solvent includes water and / or organic solvents.

19. The wafer dicing protective fluid according to claim 18, characterized in that, The organic solvent includes any one or a combination of at least two of the following: ethylene glycol, ethylene glycol tert-butyl ether, isopropanol, propylene glycol, propylene glycol monomethyl ether, ethylene glycol ethyl ether acetate, propylene glycol monomethyl ether acetate, n-butyl acetate, or dimethyl carbonate.

20. The wafer dicing protective fluid according to claim 18, characterized in that, When the solvent includes water and an organic solvent, the mass ratio of the organic solvent to water is (1~2):(3~4).

21. The wafer dicing protective fluid according to claim 1, characterized in that, The plasticizer includes any one or a combination of at least two of sorbitol, xylitol, hydroxypropyl cellulose, or triethyl citrate.

22. The wafer dicing protective fluid according to claim 1, characterized in that, The ultraviolet absorber includes any one or a combination of at least two of sodium stilbene biphenyl disulfonate, disodium phenyl dibenzimidazole tetrasulfonate, or terephthalimide dicamphor sulfonate.

23. The wafer dicing protective fluid according to claim 1, characterized in that, The leveling agent includes acrylic polymers and / or ester polymers.

24. A method for preparing a wafer dicing protective solution for laser-assisted plasma etching as described in any one of claims 1 to 23, characterized in that, The preparation method includes the following steps: (1) Mix the solvent and ultraviolet absorber according to the formula amount and stir for the first time until the materials are completely dissolved to obtain a clear and transparent first mixed solution; (2) According to the formula amount, mix the first mixed solution obtained in step (1), water-soluble furan-based polyamide resin, plasticizer and leveling agent, and stir for the second time until a clear and transparent second mixed solution is obtained. Then, discharge and filter in sequence to obtain wafer cutting protective liquid.

25. The preparation method according to claim 24, characterized in that, Step (1) The temperatures of the first and second stirring are each 30~40℃ independently.

26. The preparation method according to claim 24, characterized in that, The rotation speeds of the first and second stirring are each independently 40~80 rpm.

27. The preparation method according to claim 24, characterized in that, The first and second stirring times are each 5 to 10 hours independently.

28. The preparation method according to claim 24, characterized in that, The filtration accuracy in step (2) is 50~100nm.

29. The application of a wafer dicing protective solution as described in any one of claims 1 to 23 for laser-assisted plasma etching processes, characterized in that, The application includes the following steps: (a) A wafer dicing protective solution is applied to the surface of a semiconductor wafer and dried to form a protective film; (b) Laser cutting is performed on a specified location of a semiconductor wafer containing the protective film described in step (a) to form a processing groove with a specific pattern on the surface of the semiconductor wafer; (c) The semiconductor wafer containing the processing groove described in step (b) is subjected to plasma etching, and then cleaned, dried and tested in sequence to obtain the processed semiconductor wafer.

30. The application according to claim 29, characterized in that, The coating amount of the wafer dicing protective liquid in step (a) is 10~15mL / wafer.

31. The application according to claim 29, characterized in that, The size of the semiconductor wafer is 8 to 12 inches.

32. The application according to claim 29, characterized in that, The coating method includes spin coating.

33. The application according to claim 32, characterized in that, The spin coating speed is 1000~1500 rpm.

34. The application according to claim 29, characterized in that, The drying temperature is 60~80℃.

35. The application according to claim 29, characterized in that, The drying time is 4 to 10 minutes.

36. The application according to claim 29, characterized in that, The laser cutting rate in step (b) is 200~300mm / s.

37. The application according to claim 29, characterized in that, The power of the laser cutting is 1~2.5W.

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