Wafer cutting protection liquid for laser-assisted plasma etching process as well as preparation method and application of wafer cutting protection liquid

Abstract

The invention relates to a wafer cutting protection liquid for a laser-assisted plasma etching process and a preparation method and application of the wafer cutting protection liquid, and the wafer cutting protection liquid comprises the following components in parts by weight: 70-85 parts of water-soluble furyl polyamide resin; 15-25 parts of a solvent; 1-5 parts of a plasticizer; 0.1-1 part of an ultraviolet light absorber; and 0.1-1 part of a leveling agent. The wafer cutting protection liquid provided by the invention can form a protection film which has excellent mechanical properties, wear resistance and heat resistance and is easy to clean, and is widely applicable to thin wafer processing, deep silicon etching, TSV through hole processing technologies and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor processing, and in particular to a wafer cutting protection liquid used in a laser-assisted plasma etching process, and a preparation method and application thereof. Background Art

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

[0003] In existing research, the more advanced cutting technology for semiconductor wafers is a hybrid laser scribing and plasma cutting. The specific operations include: using a laser of a certain wavelength to irradiate a specific position of the semiconductor wafer, so that the laser interacts with the material to form a certain number of processing grooves; then transferring the wafer to a chamber with a plasma atmosphere for physical and chemical etching. The above-mentioned cutting method can selectively split the chip, and can effectively split the chip even if the scribing line is curved. In recent years, due to its extremely high etching rate, this cutting method is widely regarded as one of the best choices for cutting chips.

[0004] For example, US20160365283A1 discloses an etch-resistant water-soluble mask for hybrid wafer cutting by laser scribing and plasma etching, which includes an ultraviolet light absorbing compound, a polyvinyl alcohol resin and a solvent. The water-soluble mask increases its etching resistance by baking. After baking, the water-soluble mask is patterned using a laser scribing process to form a gap, and finally plasma etching is performed to separate the integrated circuits.

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

[0006] However, most of the existing plasma cutting protection fluids use water-soluble resins with poor heat resistance such as polyvinyl pyrrolidone (PVP) or polyvinyl alcohol (PVA), and most water-soluble resins do not have high etching 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 wafer cutting protective liquid with excellent performance for laser-assisted plasma etching process, 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] In response to the above problems, the purpose of the present invention is to provide a wafer cutting protection liquid for laser-assisted plasma etching process, and its preparation method and application. Compared with the prior art, the wafer cutting protection liquid 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 used in thin wafer processing, deep silicon etching, TSV through-hole and other processing processes.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a wafer cutting protection liquid for a laser-assisted plasma etching process, wherein the wafer cutting protection liquid comprises the following components in parts by weight:

[0011]

[0012]

[0013] The present invention adopts a compound of water-soluble furan-based polyamide resin, solvent, plasticizer, ultraviolet light absorber and leveling agent, and the obtained wafer cutting protection liquid can form a protective film with good mechanical properties, wear resistance and heat resistance, and is easy to clean, and the above materials can be recycled and reused, with the advantages of low cost and low carbon and environmental protection. Among them, on the one hand, compared with the existing polyamide resin, the water-soluble furan-based polyamide resin used in the present invention not only has extremely strong solubility in aqueous solution, but also can improve the hardness and heat resistance of the protective film, and is more flat and dense, and can effectively avoid the adverse effects of high-energy laser and plasma etching; on the other hand, the present invention cooperates with the water-soluble furan-based polyamide resin and the plasticizer, and the plasticizer can solve the problem of excessive rigidity of the water-soluble furan-based polyamide resin, so that the obtained protective film is not easy to crack under vacuum.

[0014] In the present invention, the wafer cutting protection liquid includes, by weight: 70 to 85 parts of a water-soluble furan-based polyamide resin, for example, 70 parts, 72 parts, 74 parts, 76 parts, 78 parts, 80 parts, 82 parts, 84 parts or 85 parts; 15 to 25 parts of a solvent, for example, 15 parts, 16 parts, 17 parts, 18 parts, 20 parts, 22 parts or 25 parts; 1 to 5 parts of a plasticizer, for example, 1 part, 2 parts, 3 parts, 4 parts or 5 parts; 0.1 to 1 part of an ultraviolet light absorber, for example, 0.1 part, 0.2 part, 0.4 part, 0.6 part, 0.8 part or 1 part; 0.1 to 1 part of a leveling agent, for example, 0.1 part, 0.2 part, 0.4 part, 0.6 part, 0.8 part or 1 part, but is not limited to the listed values, and other values ​​not listed within the numerical range are equally applicable. Among them, the present invention can make the plasma erosion resistance of the obtained protective film optimal and the hardness reach the most ideal state by controlling the weight proportions of the water-soluble furan-based polyamide resin and the plasticizer within a specific range; on the one hand, if the amount of the water-soluble furan-based polyamide resin is relatively too low, it is easy to cause the obtained protective film to be soft, and the formed coating cannot provide sufficient rigidity and heat resistance, resulting in weak plasma etching resistance of the wafer; on the other hand, if the amount of the water-soluble furan-based polyamide resin is relatively too high, it is easy to cause the protective film to be too rigid, and it is easy to crack during the vacuum process, which is not conducive to the subsequent etching process.

[0015] Preferably, the raw materials for preparing the water-soluble furan-based polyamide resin include: furan dicarboxylic acid diester, diamine compound and modifier.

[0016] Preferably, the furandicarboxylic acid diester includes dimethyl 2,5-furandicarboxylate and / or diethyl 2,5-furandicarboxylate.

[0017] Preferably, the diamine compound includes any one of 1,3-propylenediamine, 1,4-butylenediamine, 1,5-pentanediamine, 1,6-hexamethylenediamine, 1,3-cyclohexanedimethylamine, 1,4-cyclohexanedimethylamine, furan-2,5-diyldimethylamine or meta-xylylenediamine, or a combination of at least two thereof.

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

[0019] Preferably, the mass ratio of the furandicarboxylic acid diester to the modifier is (3-4):(1-2), for example, 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, and other unlisted values ​​within the numerical range are also applicable.

[0020] In the present invention, by adding sodium 1,3-dimethyl phthalate-5-sulfonate as a modifier, the water solubility of the furan-based polyamide resin can be further enhanced, and by preferably controlling the mass ratio of furan dicarboxylic acid diester to the modifier within a specific range, the prepared resin can have good water solubility. The present invention can increase the water solubility of the resin and improve the stability of the protective liquid by preferably controlling the amount of the modifier added. When too much or too little modifier is added, the stability of the protective liquid is likely to decrease, and problems such as particle precipitation or stratification may occur.

[0021] Preferably, the ratio of the total molar amount of the furandicarboxylic acid diester and the modifier to the molar amount of the diamine compound is 1:(1.02-1.10), 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, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, the preparation method of the water-soluble furan-based polyamide resin comprises: subjecting furan dicarboxylic acid diester, diamine compound and modifier to prepolymerization reaction 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 vacuumizing and cooling in sequence to obtain the resin.

[0023] In the present invention, the terminal temperature of the cooling is not particularly limited, and the temperature is generally controlled to be below 160° C., and then the material is discharged and pelletized.

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

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

[0026] In the present invention, the titanium citrate in the catalyst is generally ultra-pure, that is, the purity is ≥98%.

[0027] Preferably, the mass of the catalyst accounts for 1 to 3% of the total mass of the furandicarboxylic acid diester and the diamine compound, 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 numerical 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 60-90°C, for example, it can be 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, and other unlisted values ​​within the numerical range are also applicable.

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

[0031] Preferably, the first reaction temperature is 140-170°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 numerical range are also applicable.

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

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

[0035] Preferably, the terminal vacuum degree of the vacuum extraction is 40-60Pa, for example, it can be 40Pa, 42Pa, 45Pa, 48Pa, 50Pa, 52Pa, 55Pa, 58Pa or 60Pa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

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

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

[0038] Preferably, the viscosity of the water-soluble furan-based polyamide resin is 40 to 100 mPa·s, for example, it may 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 numerical range are equally applicable.

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

[0040] Preferably, the organic solvent includes any one 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, or a combination of at least two thereof.

[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, and other unlisted values ​​within the numerical range are also applicable.

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

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

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

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

[0046] (1) mixing a solvent and an ultraviolet light absorber according to the formula amount and performing a first stirring until the materials are completely dissolved to obtain a clear and transparent first mixed solution;

[0047] (2) According to the formula, the first mixed solution obtained in step (1), the water-soluble furan-based polyamide resin, the plasticizer and the leveling agent are mixed, and a second stirring is performed to obtain a clear and transparent second mixed solution, and then the mixture is discharged and filtered in sequence to obtain a wafer cutting protection solution.

[0048] The preparation method provided by the present invention can obtain a clear and transparent wafer cutting protection liquid with uniform composition through operations such as first stirring, second stirring, discharging, filtering and the like.

[0049] In the present invention, the first stirring and the second stirring are generally performed in a stirring kettle, and the stirring kettle adopts a circulating water system for temperature control.

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

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

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

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

[0054] As a preferred technical solution of the second aspect of the present invention, the preparation method comprises the following steps:

[0055] (1) mixing a solvent and an ultraviolet light absorber according to the formula amount and stirring for 5 to 10 hours at a temperature of 30 to 40° C. and a rotation speed of 40 to 80 rpm until the materials are completely dissolved to obtain a clear and transparent first mixed solution;

[0056] (2) According to the formula, the first mixed solution obtained in step (1), the water-soluble furan-based polyamide resin, the plasticizer and the leveling agent are mixed, and a second stirring is performed at a temperature of 30 to 40° C. and a rotation speed of 40 to 80 rpm for 5 to 10 hours to obtain a clear and transparent second mixed solution, and then the materials are discharged in sequence and filtered at a precision of 50 to 100 nm to obtain a wafer cutting protection solution.

[0057] In a second aspect, the present invention provides an application of a wafer cutting protection liquid for a laser-assisted plasma etching process as described in the first aspect of the present invention, wherein the application comprises the following steps:

[0058] (a) coating a wafer cutting protection liquid on the surface of a semiconductor wafer and drying the liquid to form a protection film;

[0059] (b) laser cutting a predetermined position of the semiconductor wafer having the protective film of step (a) to form a processing groove of a specific pattern on the surface of the semiconductor wafer;

[0060] (c) Plasma etching the semiconductor wafer containing the processing groove described in step (b), and then cleaning, drying and testing in sequence to obtain a processed semiconductor wafer.

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

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

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

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

[0065] Preferably, the spin coating rotation 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 values ​​not listed within the numerical 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, and other unlisted values ​​within the numerical 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 is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0068] Preferably, the cutting rate of the laser cutting 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 numerical range are also applicable.

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

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

[0071] In the present invention, the plasma etching is a conventional method in the art, and fluorine-based gas is generally used for etching. The plasma etching adopts the Bosch process, that is, SF6 gas is introduced into the reaction chamber for physical and chemical etching; then C4F8 gas is introduced into the reaction chamber for passivation to form a passivation layer; 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) comprises water, for example, ultrapure water and / or deionized water.

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

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

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

[0076] (2) In the wafer cutting protection liquid provided by the present invention, the high temperature resistance and plasma etching resistance of the protective film are improved by adding a water-soluble furan-based polyamide resin, and the problem of excessive rigidity of the water-soluble furan-based polyamide resin is solved by the mutual cooperation of the water-soluble furan-based polyamide resin and the plasticizer, so that the obtained protective film is not easy to crack under vacuum.

[0077] (3) The wafer cutting protection liquid provided by the present invention can increase its solubility in aqueous solution by controlling the preparation method of the water-soluble furan-based polyamide resin, especially controlling the addition of a modifier, and improve the hardness and heat resistance of the protective film, making the protective film layer smooth, dense, and easy to clean.

[0078] (4) Under optimal conditions, the protective film obtained by the wafer cutting protection liquid provided by the present invention has a TTV of less than 0.331 μm, a hardness of more than 3.56 MPa, and a T 5％loss Reaching above 380°C, there is no crack in the vacuum membrane surface test, the heat affected zone reaches below 1.92μm, the selective etching ratio reaches above 205, the number of 50nm particles after cleaning test is ≤10, and there is no particle precipitation in the storage test. DETAILED DESCRIPTION

[0079] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0080] Preparation Example 1

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

[0082] (i) under nitrogen atmosphere, furandicarboxylic acid diester, diamine compound and modifier are placed in a glass kettle with stirring and condensing device, and under the action of catalyst, prepolymerization reaction is carried out at 60° C. for 3 hours, then the temperature is raised to 170° C. for first reaction for 2 hours, and then the temperature is further raised to 220° C. for second reaction for 2 hours, and finally vacuuming for 1 hour until the terminal vacuum degree is 50 Pa, and then the temperature is lowered to below 160° C. for discharging and pelletizing to obtain resin;

[0083] (ii) dissolving the resin obtained in step (i) in a solvent, namely deionized water, and adjusting the pH value to 6.5 with citric acid to obtain a water-soluble furan-based polyamide resin, wherein the viscosity of the water-soluble furan-based polyamide resin is 90 mPa·s.

[0084] In this preparation example, the specific components and amounts of the furandicarboxylic acid diester, 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 furan-based polyamide resin, the preparation method comprising the following steps:

[0087] (i) under nitrogen atmosphere, furandicarboxylic acid diester, diamine compound and modifier are placed in a glass kettle with stirring and condensing device, and under the action of catalyst, 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, and then the temperature is further raised to 200° C. for a second reaction for 3 hours, and finally vacuuming for 1 hour until the terminal vacuum degree is 60 Pa, and then the temperature is lowered to below 160° C. for discharging and pelletizing to obtain resin;

[0088] (ii) dissolving the resin obtained in step (i) in a solvent, namely deionized water, and adjusting the pH value to 7 with citric acid to obtain a water-soluble furan-based polyamide resin, wherein the viscosity of the water-soluble furan-based polyamide resin is 100 mPa·s.

[0089] In this preparation example, the specific components and amounts of the furandicarboxylic acid diester, 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 furan-based polyamide resin, the preparation method comprising the following steps:

[0092] (i) under nitrogen atmosphere, furandicarboxylic acid diester, diamine compound and modifier are placed in a glass kettle with stirring and condensing device, and under the action of catalyst, prepolymerization reaction is carried out at 90° C. for 1 hour, then the temperature is raised to 140° C. for first reaction for 3 hours, and then the temperature is further raised to 230° C. for second reaction for 1 hour, and finally vacuuming for 1 hour until the terminal vacuum degree is 40 Pa, and then the temperature is lowered to below 160° C. for discharging and pelletizing to obtain resin;

[0093] (ii) dissolving the resin obtained in step (i) in a solvent, namely deionized water, and adjusting the pH value to 5 with citric acid to obtain a water-soluble furan-based polyamide resin, wherein the viscosity of the water-soluble furan-based polyamide resin is 40 mPa·s.

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

[0095] Preparation Examples 4 to 6

[0096] Preparation Examples 4 to 6 respectively provide a method for preparing a water-soluble furan-based polyamide resin. The preparation methods provided in Preparation Examples 4 to 6 are the same as Preparation Example 1 except that the specific components and amounts of furan dicarboxylic acid diester, diamine compound, modifier, catalyst and deionized water are shown in Table 1.

[0097] Preparation Example 7

[0098] This preparation example provides a preparation method for a water-soluble furan-based polyamide resin. The difference between the preparation method and Preparation Example 1 is that the amount of the modifier is changed so that the mass ratio of furan dicarboxylic acid diester to the modifier in step (i) is 4.5:1.

[0099] The specific components and amounts of furandicarboxylic acid diester, diamine compound, modifier, catalyst and deionized water in this preparation example are shown in Table 1.

[0100] Preparation Example 8

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

[0102] The specific components and amounts of furandicarboxylic acid diester, diamine compound, modifier, catalyst 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 furan-based polyamide resin. The 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 furandicarboxylic acid diester, diamine compound, modifier, catalyst and deionized water in this comparative preparation example are shown in Table 1.

[0106] Table 1

[0107]

[0108] In Table 1, “ / ” means that the component was not added.

[0109] Example 1

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

[0111] This embodiment also provides a method for preparing the above-mentioned wafer cutting protection liquid, and the preparation method comprises the following steps:

[0112] (1) Mixing the solvent and the ultraviolet light absorber in a stirring kettle according to the formula, starting the circulating water system for temperature control, and performing the first stirring for 7 hours at a temperature of 35° C. and a rotation speed of 60 rpm until the materials are completely dissolved to obtain a clear and transparent first mixed solution;

[0113] (2) According to the formula, the first mixed solution obtained in step (1), the water-soluble furan-based polyamide resin, the plasticizer and the leveling agent are mixed, and a second stirring is performed at a temperature of 35° C. and a rotation speed of 60 rpm for 7 hours to obtain a clear and transparent second mixed solution, and then the materials are discharged in sequence and filtered at an accuracy of 70 nm to obtain a wafer cutting protection solution.

[0114] Example 2

[0115] This embodiment provides a wafer cutting protection liquid for laser-assisted plasma etching process, wherein the wafer cutting protection liquid comprises a water-soluble furan-based polyamide resin, a solvent, a plasticizer, an ultraviolet light absorber and a leveling agent, wherein the water-soluble furan-based polyamide resin is obtained from Preparation Example 2. The names and amounts of the components of the wafer cutting protection liquid in this embodiment are shown in Table 2.

[0116] This embodiment also provides a method for preparing the above-mentioned wafer cutting protection liquid, and the preparation method comprises the following steps:

[0117] (1) Mixing the solvent and the ultraviolet light absorber in a stirring kettle according to the formula, starting the circulating water system for temperature control, and performing a first stirring for 5 hours at a temperature of 30° C. and a rotation speed of 80 rpm until the materials are completely dissolved to obtain a clear and transparent first mixed solution;

[0118] (2) According to the formula, the first mixed solution obtained in step (1), the water-soluble furan-based polyamide resin, the plasticizer and the leveling agent are mixed, and a second stirring is performed at a temperature of 40° C. and a rotation speed of 40 rpm for 10 hours to obtain a clear and transparent second mixed solution, and then the materials are discharged in sequence and filtered at an accuracy of 50 nm to obtain a wafer cutting protection solution.

[0119] Example 3

[0120] This embodiment provides a wafer cutting protection liquid for laser-assisted plasma etching process, wherein the wafer cutting protection liquid comprises a water-soluble furan-based polyamide resin, a solvent, a plasticizer, an ultraviolet light absorber and a leveling agent, wherein the water-soluble furan-based polyamide resin is obtained from Preparation Example 3. The names and amounts of the components of the wafer cutting protection liquid in this embodiment are shown in Table 2.

[0121] This embodiment also provides a method for preparing the above-mentioned wafer cutting protection liquid, and the preparation method comprises the following steps:

[0122] (1) Mixing the solvent and the ultraviolet light absorber in a stirring kettle according to the formula, starting the circulating water system for temperature control, and performing a first stirring for 10 hours at a temperature of 40° C. and a rotation speed of 40 rpm until the materials are completely dissolved to obtain a clear and transparent first mixed solution;

[0123] (2) According to the formula, the first mixed solution obtained in step (1), the water-soluble furan-based polyamide resin, the plasticizer and the leveling agent are mixed, and a second stirring is performed at a temperature of 30° C. and a rotation speed of 80 rpm for 5 hours to obtain a clear and transparent second mixed solution, and then the materials are discharged in sequence and filtered at an accuracy of 100 nm to obtain a wafer cutting protection solution.

[0124] Embodiments 4 to 6

[0125] Examples 4 to 6 respectively provide a wafer cutting protection liquid for laser-assisted plasma etching process, the names and amounts of the components of the wafer cutting protection liquid are shown in Table 2, wherein the water-soluble furan-based polyamide resins are respectively the water-soluble furan-based polyamide resins provided by Preparation Examples 4 to 6, and the preparation process is the same as that of Example 1.

[0126] Embodiment 7-8

[0127] Examples 7 and 8 respectively provide a wafer cutting protection liquid for laser-assisted plasma etching process, and the difference between the wafer cutting protection liquid and Example 1 is that the water-soluble furan-based polyamide resin provided by Preparation Examples 7 and 8 is respectively used. The names and amounts of the components of the wafer cutting protection liquid in Examples 7 and 8 are shown in Table 2.

[0128] Comparative Example 1

[0129] This comparative example provides a wafer cutting protection liquid for laser-assisted plasma etching process, and the difference between the wafer cutting protection liquid and Example 1 is that the water-soluble furan-based polyamide resin is replaced by the furan-based polyamide resin obtained in Comparative Preparation Example 1. The names and amounts of the components of the wafer cutting protection liquid in this comparative example are shown in Table 2.

[0130] Comparative Example 2

[0131] This comparative example provides a wafer cutting protection liquid for laser-assisted plasma etching process, and the difference between the wafer cutting protection liquid and Example 1 is that the mass of the water-soluble furan-based polyamide resin is 6.5 kg. The names and amounts of the components of the wafer cutting protection liquid in this comparative example are shown in Table 2.

[0132] Comparative Example 3

[0133] This comparative example provides a wafer cutting protection liquid for laser-assisted plasma etching process, and the difference between the wafer cutting protection liquid and Example 1 is that the mass of the water-soluble furan-based polyamide resin is 9 kg. The names and amounts of the components of the wafer cutting protection liquid in this comparative example are shown in Table 2.

[0134] Comparative Example 4

[0135] This comparative example provides a wafer cutting protection liquid for laser-assisted plasma etching process, and the difference between the wafer cutting protection liquid and Example 1 is that the mass of the plasticizer is 0.05 kg. The names and amounts of the components of the wafer cutting protection liquid in this comparative example are shown in Table 2.

[0136] Comparative Example 5

[0137] This comparative example provides a wafer cutting protection liquid for laser-assisted plasma etching process, and the difference between the wafer cutting protection liquid and Example 1 is that the mass of the plasticizer is 0.8 kg. The names and amounts of the components of the wafer cutting protection liquid in this comparative example are shown in Table 2.

[0138] Comparative Example 6

[0139] This comparative example provides a wafer cutting protection liquid for laser-assisted plasma etching process, and the difference between the wafer cutting protection liquid and Example 1 is that no plasticizer is added. The names and amounts of the components of the wafer cutting protection liquid in this comparative example are shown in Table 2.

[0140] Comparative Example 7

[0141] This comparative example provides a wafer cutting protection liquid for laser-assisted plasma etching process. The difference between the wafer cutting protection liquid and Example 1 is that the water-soluble furan-based polyamide resin is replaced by a water-soluble polyamide resin. The difference between the preparation method of the water-soluble polyamide resin and Preparation Example 1 is that 2,5-furandicarboxylic acid dimethyl ester is replaced by dimethyl terephthalate.

[0142] The names and amounts of the components of the wafer cutting protection solution in this comparative example are shown in Table 2.

[0143] Table 2

[0144]

[0145]

[0146] In Table 2, “ / ” means that the component was not added.

[0147] Application Example 1

[0148] This application example provides an application of a wafer cutting protection liquid for a laser-assisted plasma etching process, wherein the wafer cutting protection liquid is the wafer cutting protection liquid provided in Example 1, and the application includes the following steps:

[0149] (a) coating a wafer cutting protection liquid on a surface of a 12-inch semiconductor wafer by spin coating at a rotation speed of 1200 rpm and a coating amount of 12 mL / wafer, and then drying at 70° C. for 6 min to form a protective film;

[0150] (b) performing laser cutting on a predetermined position of the semiconductor wafer having the protective film of step (a), wherein the laser cutting uses 355 nm ultraviolet light, a cutting rate of 250 mm / s, and a power of 2 W, so that a processing groove of a specific pattern is formed on the surface of the semiconductor wafer;

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

[0152] Application Examples 2 to 8

[0153] The present application examples 2 to 8 respectively provide an application of a wafer cutting protection liquid for a laser-assisted plasma etching process. Except that the wafer cutting protection liquid is the wafer cutting protection liquid provided in embodiments 1 to 8, the rest is the same as application example 1.

[0154] Comparative Application Examples 1 to 7

[0155] The comparative application examples 1 to 7 respectively provide an application of a wafer cutting protection liquid for a laser-assisted plasma etching process. Except that the wafer cutting protection liquid is the wafer cutting protection liquid provided in comparative examples 1 to 7, the rest is the same as application example 1.

[0156] Performance Testing:

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

[0158] ① Membrane surface TTV: measured using the American Corning Flatmaster 200 flatness tester.

[0159] ② Membrane surface hardness: Refer to the test method provided in GB / T21838-2008 "Instrumented indentation test for hardness and material parameters of metal materials" and use a nano indenter to test.

[0160] ③Heat resistance: Use thermogravimetric analyzer to test T 5％loss , which is the temperature point corresponding to the sample losing 5% of its weight.

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

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

[0163] Heat affected zone test: Use SLG1E picosecond laser Dual Wide 1.5W 1pass and DOE Wide 11W 3pass to conduct pre-grooving condition test, and observe the heat affected zone under a microscope.

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

[0165] ① Silicon etching depth: Use SPD1A etcher PC2-test223 program (60 loops) to perform plasma dry etching test, observe and measure surface / cross-section depth.

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

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

[0168] Taking a 12-inch wafer as an example, the wafer cutting protection liquid was spin-coated at a rotation speed of 1000rpm for 240s, and then baked in a 150℃ oven for 120min. The baked wafer was taken out and placed on a spin coater. The film surface was soaked with ultrapure water for 1min, and spin coating was started (rotation speed 1000rpm). After washing with ultrapure water for 1min, it was blown dry with nitrogen, and the residual glue on the film surface was observed under a microscope, and the number of particles with a particle size greater than 50nm was recorded.

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

[0170] The wafer cutting protection liquid was sealed and placed in a 25°C constant temperature drying oven for 1 month, during which the glue liquid was visually observed.

[0171] Table 3

[0172]

[0173]

[0174]

[0175] From the data in Table 3, we can see the following points:

[0176] (1) From the data of Examples 1-6, it can be seen that the TTV of the protective film obtained by the wafer cutting protection liquid provided by the present invention is less than 0.331 μm, the hardness of the film surface is more than 3.56 MPa, and the TTV of the protective film is less than 0.331 μm. 5％loss Reaching above 380℃, there is no crack in the vacuum membrane surface test, the heat affected zone reaches below 1.92μm, the selective etching ratio reaches above 205, the number of 50nm particles after cleaning test is ≤10, and there is no particle precipitation in the glue solution.

[0177] (2) From the data of Example 1, Examples 7-8 and Comparative Example 1, it can be seen that the only difference between Examples 7-8 and Comparative Example 1 and Example 1 is that the mass ratio of furandicarboxylic acid diester to modifier in the preparation of the water-soluble furan-based polyamide resin used is not within the preferred range of the present invention and no modifier is added. The number of 50 nm particles in Examples 7-8 and Comparative Example 1 is significantly increased, and the TTV of the membrane surface of Comparative Example 1 is increased and fine cracks appear. It can be seen that the present invention can reduce particle residues by adding a modifier and controlling the mass ratio of furandicarboxylic acid diester to modifier in the preparation of the water-soluble furan-based polyamide resin, while further ensuring the stability of the protective solution 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 that the weight fraction of the water-soluble furan-based polyamide resin or the plasticizer is not within the control range of the present invention, and the difference of Comparative Example 6 is that no plasticizer is added. The selective etching ratios in Comparative Examples 2-6 are significantly reduced, and small 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 cooperates with the water-soluble furan-based polyamide resin and the plasticizer. The plasticizer can solve the problem of excessive rigidity of the water-soluble furan-based polyamide resin, so that the obtained protective film is not easy to crack under vacuum, and the protective film has good heat resistance and hardness, and improves plasma etching resistance, thereby ensuring a higher selective etching ratio.

[0179] (4) From the data of Example 1 and Comparative Example 7, it can be seen that the only difference between Comparative Example 7 and Example 1 is that the water-soluble furan-based polyamide resin is replaced by a water-soluble polyamide resin. Compared with Comparative Example 7, the heat resistance and hardness of the protective film obtained in Example 1 are higher, the heat-affected zone is significantly reduced, and the selective etching ratio is significantly improved. It can be seen that the water-soluble furan-based polyamide resin used in the present invention not only has extremely strong solubility in aqueous solution compared to the existing polyamide resin, but also can improve the hardness and heat resistance of the protective film, and can effectively avoid the adverse effects of high-energy laser and plasma etching.

[0180] In summary, the wafer cutting protection liquid provided by the present invention can form a protective film with excellent mechanical properties, wear resistance and heat resistance, and is easy to clean, and is widely used in thin wafer processing, deep silicon etching, TSV through-hole and other processing processes.

[0181] The applicant declares that the above is only a specific implementation mode 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 thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A wafer cutting protection liquid for laser-assisted plasma etching process, characterized in that: The wafer cutting protection solution comprises the following components in parts by weight:

2. The wafer cutting protection liquid according to claim 1, characterized in that: The raw materials for preparing the water-soluble furan-based polyamide resin include: furan dicarboxylic acid diester, diamine compound and modifier; Preferably, the furandicarboxylic acid diester comprises dimethyl 2,5-furandicarboxylate and / or diethyl 2,5-furandicarboxylate; Preferably, the diamine compound includes any one or a combination of at least two of 1,3-propylenediamine, 1,4-butylenediamine, 1,5-pentanediamine, 1,6-hexamethylenediamine, 1,3-cyclohexanedimethylamine, 1,4-cyclohexanedimethylamine, furan-2,5-diyldimethylamine or meta-xylylenediamine; Preferably, the modifier comprises sodium 1,3-dimethyl phthalate-5-sulfonate; Preferably, the mass ratio of the furandicarboxylic acid diester to the modifier is (3-4):(1-2); Preferably, the ratio of the total molar amount of the furandicarboxylic acid diester and the modifier to the molar amount of the diamine compound is 1:(1.02-1.10).

3. The wafer cutting protection liquid according to claim 2, characterized in that: The preparation method of the water-soluble furan-based polyamide resin comprises: The furandicarboxylic acid diester, the diamine compound and the modifier are subjected to a prepolymerization reaction under the action of a catalyst, and then the temperature is raised to a first reaction temperature for a first reaction, and then the temperature is further raised to a second reaction temperature for a second reaction, and finally vacuuming and cooling are performed in sequence to obtain a resin; Preferably, the method for preparing the water-soluble furan-based polyamide resin further comprises: dissolving the resin in water and adjusting the pH value to obtain the water-soluble furan-based polyamide resin; Preferably, the catalyst comprises any one or a combination of at least two of triethyl phosphate, titanium isopropoxide, tetrabutyl titanate or titanium citrate; Preferably, the mass of the catalyst accounts for 1-3% of the total mass of the furandicarboxylic acid diester and the diamine compound.

4. The wafer cutting protection liquid according to claim 3, characterized in that: The prepolymerization reaction, the first reaction and the second reaction are all carried out under a nitrogen atmosphere; Preferably, the prepolymerization temperature is 60 to 90°C; Preferably, the prepolymerization reaction time is 1 to 3 hours; Preferably, the first reaction temperature is 140-170°C; Preferably, the first reaction time is 1 to 3 hours; Preferably, the second reaction temperature is 200-230°C; Preferably, the second reaction time is 1 to 3 hours; Preferably, the vacuum degree at the end of the vacuuming is 40-60 Pa; Preferably, the pH regulator used for adjusting the pH value includes any one of lactic acid, citric acid, malic acid, tartaric acid or fumaric acid, or a combination of at least two thereof; Preferably, the end point pH value of the pH adjustment is 5 to 7; Preferably, the viscosity of the water-soluble furan-based polyamide resin is 40 to 100 mPa·s.

5. The wafer cutting protection liquid according to any one of claims 1 to 4, characterized in that: The solvent includes water and / or an organic solvent; Preferably, the organic solvent comprises any one 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, or a combination of at least two thereof; Preferably, when the solvent includes water and an organic solvent, the mass ratio of the organic solvent to water is (1-2):(3-4).

6. The wafer cutting protection liquid according to any one of claims 1 to 5, characterized in that: The plasticizer includes any one of sorbitol, xylitol, hydroxypropyl cellulose or triethyl citrate or a combination of at least two thereof; Preferably, the ultraviolet light absorber includes any one or a combination of at least two of sodium distyryl biphenyl disulfonate, disodium phenyl dibenzimidazole tetrasulfonate or terephthalylidene dicamphor sulfonate; Preferably, the leveling agent includes acrylic polymer and / or ester polymer.

7. A method for preparing a wafer cutting protection liquid for a laser-assisted plasma etching process according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) mixing a solvent and an ultraviolet light absorber according to the formula amount and performing a first stirring until the materials are completely dissolved to obtain a clear and transparent first mixed solution; (2) According to the formula, the first mixed solution obtained in step (1), the water-soluble furan-based polyamide resin, the plasticizer and the leveling agent are mixed, and a second stirring is performed to obtain a clear and transparent second mixed solution, and then the mixture is discharged and filtered in sequence to obtain a wafer cutting protection solution.

8. The preparation method according to claim 7, characterized in that: Step (1) The temperatures of the first stirring and the second stirring are independently 30 to 40° C.; Preferably, the rotation speeds of the first stirring and the second stirring are independently 40 to 80 rpm; Preferably, the first stirring and the second stirring time are each independently 5 to 10 hours; Preferably, the filtering accuracy in step (2) is 50 to 100 nm.

9. An application of the wafer cutting protection liquid for laser-assisted plasma etching process according to any one of claims 1 to 6, characterized in that: The application comprises the following steps: (a) coating a wafer cutting protection liquid on the surface of a semiconductor wafer and drying the liquid to form a protection film; (b) laser cutting a predetermined position of the semiconductor wafer having the protective film of step (a) to form a processing groove of a specific pattern on the surface of the semiconductor wafer; (c) Plasma etching the semiconductor wafer containing the processing groove described in step (b), and then cleaning, drying and testing in sequence to obtain a processed semiconductor wafer.

10. The use according to claim 9, characterized in that: The coating amount of the wafer cutting protection liquid in step (a) is 10-15 mL / wafer; Preferably, the size of the semiconductor wafer is 8 to 12 inches; Preferably, the coating method includes spin coating; Preferably, the spin coating speed is 1000-1500 rpm; Preferably, the drying temperature is 60-80°C; Preferably, the drying time is 4 to 10 minutes; Preferably, the cutting rate of the laser cutting in step (b) is 200 to 300 mm / s; Preferably, the power of the laser cutting is 1-2.5W.

Images