Plasma cutting protection fluid and its use

Abstract

The application discloses a kind of plasma cutting protection fluid and its application, by mass parts, plasma cutting protection fluid includes following component: 5-12 parts of water-soluble resin, 1-5 parts of polymer electrolyte, 0.05-0.25 parts of corrosion inhibitor, 0.01-0.1 parts of leveling agent, 0.01-0.1 parts of plasticizer, 5-10 parts of organic solvent, 50-80 parts of ultrapure water;Wherein, polymer electrolyte is used to adsorb and conduct metal ion to the direction of migration away from wafer surface, so that metal ion and metal bonding structure do not contact.In the application, the polymer electrolyte used has strong adsorption, can tightly adsorb metal ions, so that metal ions preferentially migrate along the polymer electrolyte molecular chain from the bottom of the membrane layer to the top of the membrane layer, avoiding the problem that metal ions migrate and precipitate along the chip surface.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor chip cutting technology, and specifically relates to a plasma cutting protective liquid and its application. Background Art

[0002] During plasma dicing of wafers, a cutting protection fluid is applied to the wafer surface to allow the plasma beam to penetrate the exposed dicing lanes and cut the wafer into chips. Multiple metal contact points on the chip enable bonding between different chips. However, when the cutting protection fluid is applied directly to the wafer, it coats and corrodes the metal electrode structures (pads), producing metal ions. These metal ions migrate and reduce within the liquid environment of the cutting protection fluid, then precipitate again on the chip surface as metal dendrites, affecting the chip's surface cleanliness. Summary of the Invention

[0003] Purpose of application: This application provides a plasma cutting protective fluid and its application to solve the problem of metal dendrites generated on the chip surface, which affects the chip performance.

[0004] Technical solution: The present application provides a plasma cutting protection liquid for coating the surface of a wafer, wherein the surface of the wafer includes a plurality of metal electrode structures, the metal electrode structures are capable of being corroded, and free metal ions are formed in the plasma cutting protection liquid. The plasma cutting protection liquid includes the following components, in parts by mass: 5-12 parts of a water-soluble resin, 1-5 parts of a polymer electrolyte, 0.05-0.25 parts of a corrosion inhibitor, 0.01-0.1 parts of a leveling agent, 0.01-0.1 parts of a plasticizer, 5-10 parts of an organic solvent, and 50-80 parts of ultrapure water;

[0005] The polymer electrolyte is used to adsorb and conduct the metal ions to migrate in a direction away from the wafer surface, so that the metal ions do not contact the metal electrode structure.

[0006] In some embodiments, the polymer electrolyte has the following structural formula:

[0007]

[0008] Wherein, n1 represents the degree of polymerization, the range of n1 is an integer from 100 to 300, and the molecular weight range is 20,000 to 100,000; R1 is C m H 2m SO3M, m ranges from 4 to 8, and M is selected from any one of Li, Na, K, and H.

[0009] Furthermore, the M is preferably Li.

[0010] In some embodiments, the polymer electrolyte has a number average molecular weight of 20,000 to 100,000.

[0011] In some embodiments, the water-soluble resin is selected from at least one of polyvinyl alcohol, polyvinyl pyrrolidone, polyalkylene glycol, alkyl cellulose, polyacrylic acid, sodium polyacrylate, sodium salt of acrylic acid and maleic acid copolymer, sodium polystyrene sulfonate, and sodium salt of acrylic acid and sodium vinyl sulfonate copolymer.

[0012] In some embodiments, the water-soluble resin has a number average molecular weight of 5,000 to 500,000.

[0013] In some embodiments, the corrosion inhibitor is selected from at least one of an organic acid, a nitrogen-containing organic compound, and a polyol;

[0014] The organic acid is selected from at least one of formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, citric acid, tartaric acid, oleic acid, benzoic acid, salicylic acid, maleic acid, dodecylbenzenesulfonic acid, ascorbic acid, isononanoic acid, neodecanoic acid, lauric acid, sebacic acid, ethylenediaminetetraacetic acid, and sulfosuccinic acid;

[0015] The nitrogen-containing organic compound is selected from at least one of monoethanolamine, diethanolamine, triethanolamine, dimethylethanolamine, ethylenediamine, benzotriazole, benzothiazole, tolylbenzotriazole, hydroxybenzotriazole, and morpholine;

[0016] The polyol is selected from at least one of ethylene glycol, glycerol, propylene glycol, diethylene glycol, and isohexylene glycol.

[0017] In some embodiments, the leveling agent is selected from at least one of polyoxyethylene alkyl esters, alkyl glycosides, polyoxyethylene sorbitol esters, alkylphenol polyoxyethylene ethers, polyoxyethylene alkylamines, polyoxyethylene castor oil, polyoxyethylene sorbitol, alkyl glycoside esters, and fatty amide betaine.

[0018] In some embodiments, the plasticizer is selected from at least one of diethyl phthalate, dibutyl phthalate, di(2-ethylhexyl) phthalate, diisononyl phthalate, diisodecyl phthalate, dioctyl adipate, dioctyl fumarate, dioctyl succinate, tri(2-ethylhexyl) phosphate, and triphenyl phosphate.

[0019] In some embodiments, the organic solvent is selected from at least one of methanol, ethanol, propanol, isopropanol, propylene glycol methyl ether, dipropylene glycol methyl ether, ethylene glycol methyl ether, ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol ethyl ether, and diethylene glycol ethyl ether.

[0020] In some embodiments, the present application also provides the use of the plasma cutting protection liquid in chip plasma cutting.

[0021] Compared with the prior art, the beneficial effect of the present application is that: a plasma cutting protection liquid of the present application is used to coat the surface of a wafer, the surface of the wafer includes multiple metal electrode (Pad) structures, the metal electrode (Pad) structures can be corroded to form free metal ions in the plasma cutting protection liquid, and the plasma cutting protection liquid includes the following components, in parts by mass: 5-12 parts of a water-soluble resin, 1-5 parts of a polymer electrolyte, 0.05-0.25 parts of a corrosion inhibitor, 0.01-0.1 parts of a leveling agent, 0.01-0.1 parts of a plasticizer, 5-10 parts of an organic solvent, and 50-80 parts of ultrapure water; wherein the polymer electrolyte is used to adsorb and conduct metal ions to migrate away from the wafer surface so that the metal ions do not contact the metal electrode structure. The polymer electrolyte used in this application has strong adsorption properties and can tightly adsorb metal ions, so that the metal ions preferentially migrate from the bottom of the membrane layer to the top of the membrane layer along the polymer electrolyte molecular chain. Since the polymer electrolyte has a high ion density and lower resistance, the metal ions will preferentially migrate along the line with lower resistance, which avoids the problem of metal ions migrating and precipitating along the surface of the chip; in addition, in this application, a water-soluble resin is set, which has good compatibility with the polymer electrolyte, so that the polymer electrolyte is evenly distributed in the entire membrane layer, thereby achieving the effect of the polymer electrolyte being able to quickly conduct metal ions.

[0022] It can be understood that the use of the plasma cutting protection liquid provided in the embodiment of the present application has all the technical features and beneficial effects of the above-mentioned plasma cutting protection liquid, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings will make the technical solutions and other beneficial effects of the present application apparent.

[0024] Figure 1 This is a schematic diagram of the principle of generating Cu dendrites in Comparative Example 1 of the present application;

[0025] Figure 2 Schematic diagram of the principle of avoiding the generation of Cu dendrites in the embodiment of the present application;

[0026] Figure 3 This is a scanning electron microscope image of the wafer surface after using the plasma cutting protection liquid of Example 1 of the present application, with a magnification of 800;

[0027] Figure 4 This is a scanning electron microscope image of the wafer surface after using the plasma cutting protection liquid of Comparative Example 1 of the present application, with a magnification of 1200. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present application and the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0029] In the description of the present application, it should be noted that the specific embodiments described herein are only used to illustrate and explain the present application and are not used to limit the present application. In the present application, unless otherwise specified, the directional words used, such as "upper" and "lower", specifically refer to the directions of the drawings in the accompanying drawings. In addition, in the description of the present application, the term "including" means "including but not limited to". The various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated in this article, it is meant to include any quoted number (fractional or integer) within the indicated range.

[0030] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application.

[0031] The key to 2.5D / 3D advanced packaging technology is ultra-high-density Cu-Cu hybrid bonding technology, which involves tightly bonding single chips with different functions together through Cu contact points on the chip surface. At the same time, through heat treatment, the atomic diffusion of copper metal in the solid state is used to achieve a close connection between chips.

[0032] To achieve high-quality hybrid bonding, the Cu pad surface of the bonded chip must be kept extremely clean, meaning the number of particles larger than 0.12μm must be less than 10. To meet this requirement, plasma cutting technology must be used when cutting the wafer into individual chips. Because the cutting debris generated by the scribing wheel and the silicon slag generated by laser cutting will cause the particle count on the chip surface to not meet the required level, plasma cutting etches and cuts the substrate with plasma gas, without generating any debris or slag, making it a pollution-free chip cutting technology.

[0033] Plasma cutting must use plasma cutting protection fluid (referred to as protection fluid) as a temporary mask, that is, a protection fluid coating is coated on the surface of the chip, only the cutting path is exposed, and the plasma beam penetrates the exposed cutting path to cut the chip. After cutting, the protection fluid coating is removed by water washing. However, the protection fluid covers the chip surface, and the Cu Pad on the chip surface is in contact with the protection fluid, which is equivalent to the Cu Pad being wrapped in an electrolyte environment, and ion migration washing out will occur, that is, Cu dendrite problem. The principle is that the protection fluid corrodes the Cu electrode to produce Cu ions, and the Cu ions migrate from the low-potential Cu Pad to the high-potential Cu Pad in the electrolyte environment formed by the protection fluid, and then are reduced to Cu element at the high-potential Cu Pad, that is, Cu dendrite.

[0034] Therefore, it is necessary to develop a plasma cutting protection fluid to solve the Cu dendrite problem generated in plasma cutting.

[0035] The embodiment of the present application provides a kind of plasma cutting protection fluid, for coating on the surface of wafer, the surface of wafer includes multiple metal electrode structures, metal electrode structure can be corroded to form free metal ion in plasma cutting protection fluid, by mass parts, plasma cutting protection fluid includes the following components: 5-12 parts of water-soluble resin, 1-5 parts of polymer electrolyte, 0.05-0.25 parts of corrosion inhibitor, 0.01-0.1 parts of leveling agent, 0.01-0.1 parts of plasticizer, 5-10 parts of organic solvent, 50-80 parts of ultrapure water;Wherein, polymer electrolyte is used to adsorb and conduct metal ion to migrate in the direction away from the surface of wafer, so that metal ion does not contact with metal electrode structure.

[0036] It can be understood that metal electrode structure can be understood as Cu Pad bonded to the surface of chip, and Cu Pad refers to the copper (Cu) surface bonded to the chip, which is the part connected to other metals during the bonding process. When the surface of the chip is coated with plasma cutting protection fluid, the cutting protection fluid will wrap the metal bonding structure and corrode the metal bonding structure to produce metal ions in the cutting protection fluid. For Cu Pad part, the metal ion produced is copper ion. For further details, Figure 1 When copper ions are precipitated from one Cu Pad, they will migrate laterally in the protection fluid to the vicinity of the adjacent high-potential Cu Pad and be reduced to Cu element at the Cu Pad, that is, Cu dendrite. In the embodiment, by adding polymer electrolyte to the cutting protection fluid, the migration path of copper ions can be changed. For further details, Figure 2Copper ions preferentially migrate longitudinally along the polymer electrolyte molecular chains from the bottom to the top of the membrane layer, rather than laterally migrating toward other Cu pads. This results in the copper ions being located far from the chip surface and unable to contact the Cu pads, significantly reducing the formation of Cu dendrites. Because the polymer electrolyte has a high ion density and lower resistance, metal ions preferentially migrate along lower-resistance paths, thus avoiding the problem of metal ion migration and precipitation along the chip surface.

[0037] Furthermore, in this embodiment, a polymer electrolyte is added to a water-soluble resin. The water-soluble resin dissolved in deionized water can facilitate the formation of a film of the cutting protection liquid on the chip surface. The polymer electrolyte has good compatibility with the water-soluble resin, so that the polymer electrolyte can be evenly distributed in the entire film layer, thereby ensuring that the metal ions migrate away from the chip surface, thereby achieving the effect of rapid conduction of metal ions by the polymer electrolyte.

[0038] In some embodiments, the preferred components of the plasma cutting protection liquid are, by mass, 10 parts of a water-soluble resin, 2 parts of a polymer electrolyte, 0.15 parts of a corrosion inhibitor, 0.06 parts of a leveling agent, 0.04 parts of a plasticizer, 8 parts of an organic solvent, and 65 parts of ultrapure water.

[0039] In some embodiments, the polymer electrolyte has the following structural formula:

[0040]

[0041] Wherein, n1 represents the degree of polymerization, and n1 ranges from an integer of 100 to 300; R1 is C m H 2m SO3M, m ranges from 4 to 8, and M is selected from any one of Li, Na, K, and H.

[0042] It is understood that in the above-mentioned polymer electrolyte, the S atom exists in R1. S has a lone pair of electrons available for coordination and can form a coordination bond with the Cu metal ion with an empty orbital. Therefore, the polymer electrolyte has the function of adsorbing Cu ions, thereby achieving the ability of charge adsorption. At the same time, S atoms also exist in the monomer structure of the polymer electrolyte (the S atoms are obtained by sulfonation of 3-alkylthiophene). The S atoms in the monomer structure also have unpaired lone pairs of electrons, which can form coordination bonds with Cu ions, further promoting the adsorption and conduction of metal ions by the polymer electrolyte.

[0043] In some embodiments, R1 is C m H 2m SO3M can be C4H8SO3Na, C5H 10 SO3Na、C6H 12SO3K、C7H 14 SO3Na、C8H 16 SO3Na、C8H 16 SO3H、C8H 16 SO3Li、C8H 16 At least one of SO3K.

[0044] In some embodiments, when the polymer electrolyte has the following structural formula: The preparation method includes: the first step, preparation of 3-alkylthiophene; the second step, sulfonation of 3-alkylthiophene; and the third step, polymerization of sulfonated 3-alkylthiophene. Taking 3-octylthiophene as an example, the specific process for preparing the polymer electrolyte is as follows:

[0045] (1) Preparation of 3-octylthiophene

[0046] Prepare 5 g of thiophene, 5 mL of bromine (Br2), and 50 mL of dichloromethane (DCM).

[0047] Add thiophene and dichloromethane to a three-necked flask and stir to completely dissolve them; place the flask in an ice-water bath and cool to 0°C; under stirring, slowly add bromine to the flask through a separatory funnel, and control the addition time within 30 minutes to ensure that the temperature remains between 0-5°C; after the addition is completed, continue to stir and react in an ice-water bath for 2 hours; after the reaction is completed, use a separatory funnel to separate the organic layer and the aqueous layer, wash the organic layer with water 3 times, each time with 20 mL; dry the organic layer to obtain 3-bromothiophene.

[0048] Prepare 10 g of 3-bromothiophene, 2.5 g of magnesium powder, 50 mL of anhydrous ether, and 10 g of 1-bromooctane.

[0049] Grignard reaction of 3-bromothiophene: under nitrogen protection, add anhydrous ether and magnesium powder to a three-necked flask; slowly add 3-bromothiophene, and reflux the reaction under stirring for 2 hours to generate 3-thienylmagnesium bromide; slowly add 1-bromooctane to the reaction mixture, and continue to reflux the reaction under nitrogen protection for 4 hours; after the reaction is completed, cool to room temperature, pour the reaction mixture into ice water, and precipitate 3-octylthiophene; use a separatory funnel to separate the organic layer and the aqueous layer, and wash the organic layer with water three times, each time with 20 mL; dry the organic layer, and purify it by distillation to obtain 3-octylthiophene.

[0050] (2) Sulfonation of 3-octylthiophene

[0051] Prepare 1.0 g of 3-octylthiophene (CAS: 65016-62-8), 2.0 mL of chlorosulfonic acid (CAS: 7790-94-5), 20 mL of dichloromethane (CAS: 75-09-2), and 20 mL of 1 M sodium hydroxide (NaOH) solution.

[0052] Add 3-octylthiophene and dichloromethane to a three-necked flask and stir to completely dissolve them; place the flask in an ice-water bath and cool to 0°C; while stirring, slowly add chlorosulfonic acid to the flask using a separatory funnel, and control the addition time within 30 minutes, ensuring that the temperature remains at 0-5°C; after the addition is completed, continue stirring in the ice-water bath to react for 2 hours; after the reaction is completed, slowly add 20 mL of ice water to carry out a hydrolysis reaction to obtain a sulfonated product solution.

[0053] In an ice-water bath, the sulfonated product solution was slowly added dropwise to the sodium hydroxide solution, and the dropping speed was controlled to prevent a violent reaction. After the dropwise addition was completed, the reaction was continued to stir at room temperature for 1 hour. The organic layer and the aqueous layer were separated using a separatory funnel, and the organic layer was washed with dichloromethane 3 times, each time with 20 mL. The aqueous layer was collected and the pH was adjusted to neutral with concentrated hydrochloric acid to precipitate the sodium sulfonate product. The solid product was collected by filtration and dried in a vacuum drying oven to obtain sulfonated 3-octylthiophene.

[0054] (3) Polymerization of sulfonated 3-octylthiophene

[0055] Prepare 1.0 g of 3-octylthiophene monomer containing a sodium sulfonate group, 0.1 g of iron bromide (FeBr3), and 20 mL of chloroform (CHCl3).

[0056] A 3-octylthiophene monomer containing a sodium sulfonate group and chloroform were added to a three-necked flask and stirred to dissolve; ferric bromide was added as a catalyst; a reflux condenser was installed, and the reaction was refluxed at 80°C for 24 hours; after the reaction was completed, the reaction was cooled to room temperature, and the reaction mixture was poured into methanol to precipitate a polymer; the solid polymer was collected by filtration and dried in a vacuum drying oven to obtain the target polymer electrolyte.

[0057] It is understandable that polymer electrolytes with other structures can be prepared using similar preparation methods as described above.

[0058] In some embodiments, the number average molecular weight of the polymer electrolyte is in the range of 20,000 to 100,000. For example, the number average molecular weight can be any one of 20,000, 25,000, 30,000, 35,000, 40,000, 45,000, 50,000, 60,000, 70,000, 80,000, 90,000, or 100,000, or a range between any two of these values. Within this range, the polymer electrolyte can maintain its electron nucleus adsorption capacity while improving its compatibility with the water-soluble resin, further promoting uniform distribution of the polymer electrolyte throughout the membrane layer.

[0059] In some embodiments, the water-soluble resin is selected from at least one of polyvinyl alcohol, polyvinyl pyrrolidone, polyalkylene glycol, alkyl cellulose, polyacrylic acid, sodium polyacrylate, sodium salt of a copolymer of acrylic acid and maleic acid, sodium polystyrene sulfonate, and sodium salt of a copolymer of acrylic acid and sodium vinyl sulfonate. It will be appreciated that the water-soluble resin, as the base material of the protective liquid, is soluble in a solvent such as water and capable of forming a transparent film layer after spin coating and drying.

[0060] In some embodiments, the number average molecular weight of the water-soluble resin is in the range of 5000 to 500000. For example, the number average molecular weight of the water-soluble resin can be any one of 5000, 6000, 7000, 8000, 9000, 10000, 50000, 100000, 150000, 200000, 250000, 300000, 350000, 400000, 500000, or a range between any two of the values.

[0061] Furthermore, the water-soluble resin is preferably polyvinyl alcohol (PVA), more preferably polyvinyl alcohol with an alcoholysis degree of 80-98 and a polymerization degree of 300-1000, and most preferably polyvinyl alcohol with an alcoholysis degree of 88 and a polymerization degree of 600.

[0062] In some embodiments, the corrosion inhibitor is selected from at least one of organic acids, nitrogen-containing organic compounds, and polyols. The corrosion inhibitor is used to prevent other metal structures on the wafer surface, such as Al Pad, from being etched and corroded.

[0063] In some embodiments, the organic acid is selected from at least one of formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, citric acid, tartaric acid, oleic acid, benzoic acid, salicylic acid, maleic acid, ascorbic acid, isononanoic acid, neodecanoic acid, lauric acid, sebacic acid, ethylenediaminetetraacetic acid, and sulfosuccinic acid. Preferably, at least one of citric acid, tartaric acid, and ethylenediaminetetraacetic acid is selected.

[0064] In some embodiments, the nitrogen-containing organic compound comprises an amine compound or an azole compound, and is selected from at least one of monoethanolamine, diethanolamine, triethanolamine, dimethylethanolamine, ethylenediamine, benzotriazole, benzothiazole, tolylbenzotriazole, hydroxybenzotriazole, and morpholine. Preferably, at least one of benzotriazole, benzothiazole, and hydroxybenzotriazole is selected.

[0065] In some embodiments, the polyol is selected from at least one of ethylene glycol, glycerol, propylene glycol, diethylene glycol, and isohexylene glycol.

[0066] In some embodiments, the leveling agent is selected from at least one of polyoxyethylene alkyl esters, alkyl glycosides, polyoxyethylene sorbitol esters, alkylphenol polyoxyethylene ethers, polyoxyethylene alkylamines, polyoxyethylene castor oil, polyoxyethylene sorbitol, alkyl glycoside esters, and fatty amide betaines. It is understood that the leveling agent is used to improve the uniformity of the protective liquid film formed on the wafer surface. Any substance that can be added to the cutting protective liquid to reduce the surface tension to within 40 mM / m can be used as a leveling agent.

[0067] In some embodiments, the leveling agent is preferably at least one of alkylphenol polyoxyethylene ether and polyoxyethylene alkyl ester, more preferably alkylphenol polyoxyethylene ether, such as at least one of octylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, and dodecylphenol polyoxyethylene ether, and most preferably nonylphenol polyoxyethylene ether with an EO (epoxy) number of 7.

[0068] In some embodiments, the alkyl glycoside is preferably dodecyl glucoside.

[0069] In some embodiments, the fatty amide betaine is preferably cocamidopropyl betaine.

[0070] In some embodiments, the plasticizer is selected from at least one of diethyl phthalate, dibutyl phthalate, di(2-ethylhexyl) phthalate, diisononyl phthalate, diisodecyl phthalate, dioctyl adipate, dioctyl fumarate, dioctyl succinate, tri(2-ethylhexyl) phosphate, and triphenyl phosphate. It is understood that the plasticizer serves to improve the toughness of the film layer and prevent cracking on the film surface.

[0071] In some embodiments, diethyl phthalate (DEP), dibutyl phthalate (DBP), di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), and diisodecyl phthalate (DIDP) are phthalates; dioctyl adipate (DOS), dioctyl fumarate (DOP), and dioctyl succinate (DOA) are fatty acid esters; tri(2-ethylhexyl) phosphate (TCP) and triphenyl phosphate (TPP) are phosphate esters; and the plasticizer is preferably selected from at least one of diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl fumarate (DOP), and dioctyl succinate (DOA).

[0072] In some embodiments, the organic solvent is selected from at least one of methanol, ethanol, propanol, isopropanol, propylene glycol methyl ether, dipropylene glycol methyl ether, ethylene glycol methyl ether, ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol ethyl ether, and diethylene glycol ethyl ether.

[0073] In some embodiments, the present application further provides a method for preparing a plasma cutting protective liquid, comprising the following steps:

[0074] Weigh 5-12 parts of a water-soluble resin, 1-5 parts of a polymer electrolyte, 0.05-0.25 parts of a corrosion inhibitor, 0.01-0.1 parts of a leveling agent, 0.01-0.1 parts of a plasticizer, 5-10 parts of an organic solvent, and 50-80 parts of ultrapure water respectively; stir and mix the above components until they are dissolved to obtain a plasma cutting protection liquid.

[0075] In some embodiments, the specific stirring process conditions are: stirring at a speed of 200-500 rpm for 1-5 hours at room temperature, where room temperature refers to a temperature of 20-30°C.

[0076] In some embodiments, the stirring speed is any one of 200 rpm, 300 rpm, 400 rpm, 500 rpm, or a range between any two of the values.

[0077] In some embodiments, the stirring time is any one of 1 h, 2 h, 3 h, 4 h, and 5 h, or a range between any two values.

[0078] In some embodiments, a method for using a plasma cutting protective fluid is provided, as follows:

[0079] First clean the wafer to be coated;

[0080] Set up the spin coating program, add 15-40mL of cutting protection liquid (depending on the size of the wafer) to the wafer, and spin coat at 1000rpm for 2 minutes;

[0081] After spin coating, the next plasma cutting process is carried out.

[0082] In some embodiments, a plasma cutting protection liquid is provided for use in chip plasma cutting. It can be used for wafer cutting protection and can adapt to various wafer sizes and structures. A protective film is formed on the wafer surface to ensure that the wafer is not scratched by fragments during the cutting process. At the same time, it can also prevent the lateral migration and precipitation of metal ions, avoid the formation of metal dendrites on the chip surface, and improve the yield of semiconductor products and the efficiency of cutting.

[0083] In some embodiments, ultrapure water is deionized water with a resistance of ≥18 MΩ.

[0084] It should be noted that all raw materials in the following examples can be obtained from commercial sources. The molecular weight range does not mean its exact molecular weight, but rather a suitable range of fluctuations (for example, the molecular weight can be measured by various viscosity methods).

[0085] Example 1

[0086] A plasma cutting protection fluid is provided, comprising: a water-soluble resin, a polymer electrolyte, a corrosion inhibitor, a leveling agent, a plasticizer, an organic solvent, and ultrapure water. The components are weighed in respective amounts and stirred at 300 rpm for 3 hours at 25° C. to obtain the plasma cutting protection fluid. The specific substances and quantities of the components used in Example 1 are shown in Table 1.

[0087] Among them, the structural formula of the polymer electrolyte is: n1 is 200; R1 is C8H 16 SO3Li.

[0088] Example 2

[0089] A plasma cutting protection fluid is provided, comprising: a water-soluble resin, a polymer electrolyte, a corrosion inhibitor, a leveling agent, a plasticizer, an organic solvent, and ultrapure water. The components are weighed in respective amounts and stirred at 300 rpm for 3 hours at 25° C. to obtain the plasma cutting protection fluid. The specific substances and quantities of the components used in Example 2 are shown in Table 1.

[0090] Among them, the structural formula of the polymer electrolyte is: n1 is 100; R1 is C8H 16 SO3H.

[0091] Example 3

[0092] A plasma cutting protection fluid is provided, comprising: a water-soluble resin, a polymer electrolyte, a corrosion inhibitor, a leveling agent, a plasticizer, an organic solvent, and ultrapure water. The components are weighed in respective amounts and stirred at 300 rpm for 3 hours at 25° C. to obtain the plasma cutting protection fluid. The specific substances and quantities of the components used in Example 3 are shown in Table 1.

[0093] Among them, the structural formula of the polymer electrolyte is: n1 is 150; R1 is C4H8SO3Na.

[0094] Example 4

[0095] A plasma cutting protection fluid is provided, comprising: a water-soluble resin, a polymer electrolyte, a corrosion inhibitor, a leveling agent, a plasticizer, an organic solvent, and ultrapure water. The components are weighed in respective amounts and stirred at 300 rpm for 3 hours at 25° C. to obtain the plasma cutting protection fluid. The specific substances and quantities of the components used in Example 4 are shown in Table 1.

[0096] Among them, the structural formula of the polymer electrolyte is: n1 is 300; R1 is C6H 12 SO3K.

[0097] Example 5

[0098] A plasma cutting protection fluid is provided, comprising: a water-soluble resin, a polymer electrolyte, a corrosion inhibitor, a leveling agent, a plasticizer, an organic solvent, and ultrapure water. The components are weighed in respective amounts and stirred at 300 rpm for 3 hours at 25° C. to obtain the plasma cutting protection fluid. The specific substances and quantities of the components used in Example 5 are shown in Table 1.

[0099] Among them, the structural formula of the polymer electrolyte is: n1 is 300; R1 is C6H 12 SO3K.

[0100] Example 6

[0101] A plasma cutting protection fluid is provided, comprising: a water-soluble resin, a polymer electrolyte, a corrosion inhibitor, a leveling agent, a plasticizer, an organic solvent, and ultrapure water. The components are weighed in respective amounts and stirred at 300 rpm for 3 hours at 25° C. to obtain the plasma cutting protection fluid. The specific substances and quantities of the components used in Example 6 are shown in Table 1.

[0102] Among them, the structural formula of the polymer electrolyte is: n1 is 300; R1 is C6H 12 SO3K.

[0103] Example 7

[0104] A plasma cutting protection fluid is provided, comprising: a water-soluble resin, a polymer electrolyte, a corrosion inhibitor, a leveling agent, a plasticizer, an organic solvent, and ultrapure water. The components are weighed in respective amounts and stirred at 300 rpm for 3 hours at 25° C. to obtain the plasma cutting protection fluid. The specific substances and quantities of the components used in Example 7 are shown in Table 1.

[0105] Among them, the structural formula of the polymer electrolyte is: n1 is 300; R1 is C6H 12 SO3K.

[0106] Example 8

[0107] A plasma cutting protection fluid is provided, comprising: a water-soluble resin, a polymer electrolyte, a corrosion inhibitor, a leveling agent, a plasticizer, an organic solvent, and ultrapure water. The components are weighed in respective amounts and stirred at 300 rpm at 25° C. for 3 hours to obtain the plasma cutting protection fluid. The specific substances and quantities of the components used in Example 8 are shown in Table 1.

[0108] Among them, the structural formula of the polymer electrolyte is: n1 is 300; R1 is C6H 12 SO3K.

[0109] Table 1

[0110]

[0111]

[0112] Comparative Example 1

[0113] A plasma cutting protection liquid is provided, which differs from Example 1 in that it does not contain the polymer electrolyte used in Example 1. The specific components thereof include: 10 parts of a water-soluble resin, 0.15 parts of a corrosion inhibitor, 0.06 parts of a leveling agent, 0.04 parts of a plasticizer, 8 parts of an organic solvent, and 65 parts of ultrapure water.

[0114] The plasma cutting protection liquid of Examples 1-8 and Comparative Example 1 was applied to the wafer surface by spin coating. After a period of time, the surface protection liquid was washed off with pure water, and the wafer surface was observed to see whether there were Cu dendrites. Specific test data can be found in Table 2.

[0115] Table 2

[0116] With Cu dendrites Example 1 No Example 2 No Example 3 No Example 4 No Example 5 No Example 6 No Example 7 No Example 8 No Comparative Example 1 With Cu dendrites

[0117] See Table 2 and further combine Figure 3 and Figure 4 ; Figure 3 This is a scanning electron microscope image of the wafer surface after coating with the plasma cutting protection liquid of Example 1. Figure 3 There is no dendrite phenomenon on the surface of the wafer; Figure 4 This is a scanning electron microscope image of the wafer surface after the plasma cutting protection liquid is applied in Comparative Example 1. Figure 4 In the figure, a large amount of Cu elemental precipitation can be seen near the Cu Pad, resulting in dendrites. Therefore, in Examples 1-8, the use of polymer electrolytes allows for tight adsorption of metal ions, allowing them to preferentially migrate from the bottom to the top of the membrane along the polymer electrolyte molecular chains, thus avoiding the problem of metal ion migration and precipitation along the chip surface. In contrast, in Comparative Example 1, which lacks a polymer electrolyte, the problem of metal ion migration and precipitation on the chip surface cannot be avoided, resulting in the formation of Cu dendrites.

[0118] The above is a detailed introduction to the plasma cutting protective liquid and its application provided in the embodiments of the present application. Specific examples are used in this application to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application; ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A plasma cutting protection liquid for coating on the surface of a wafer, wherein the surface of the wafer comprises a plurality of metal electrode structures, wherein the metal electrode structures can be corroded to form free metal ions in the plasma cutting protection liquid, characterized in that: The plasma cutting protection fluid comprises the following components, in parts by mass: 5-12 parts of a water-soluble resin, 1-5 parts of a polymer electrolyte, 0.05-0.25 parts of a corrosion inhibitor, 0.01-0.1 parts of a leveling agent, 0.01-0.1 parts of a plasticizer, 5-10 parts of an organic solvent, and 50-80 parts of ultrapure water; The structural formula of the polymer electrolyte is shown below: Wherein, n1 represents the degree of polymerization, and the range of n1 is an integer from 100 to 300; R1 is C m H 2m SO3M, m ranges from 4 to 8, and M is selected from any one of Li, Na, K, and H; The polymer electrolyte is used to adsorb and conduct the metal ions to migrate in a direction away from the wafer surface, so that the metal ions do not contact the metal electrode structure.

2. The plasma cutting protection liquid according to claim 1, characterized in that: The number average molecular weight of the polymer electrolyte is 20,000 to 100,000.

3. The plasma cutting protection liquid according to claim 1, characterized in that: The water-soluble resin is selected from at least one of polyvinyl alcohol, polyvinyl pyrrolidone, polyalkylene glycol, alkyl cellulose, polyacrylic acid, sodium polyacrylate, sodium salt of acrylic acid and maleic acid copolymer, sodium polystyrene sulfonate, and sodium salt of acrylic acid and sodium vinyl sulfonate copolymer.

4. The plasma cutting protection liquid according to claim 3, characterized in that: The number average molecular weight of the water-soluble resin is 5,000 to 500,000.

5. The plasma cutting protection liquid according to claim 1, characterized in that: The corrosion inhibitor is selected from at least one of organic acids, nitrogen-containing organic compounds, and polyols; The organic acid is selected from at least one of formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, citric acid, tartaric acid, oleic acid, benzoic acid, salicylic acid, maleic acid, dodecylbenzenesulfonic acid, ascorbic acid, isononanoic acid, neodecanoic acid, lauric acid, sebacic acid, ethylenediaminetetraacetic acid, and sulfosuccinic acid; The nitrogen-containing organic compound is selected from at least one of monoethanolamine, diethanolamine, triethanolamine, dimethylethanolamine, ethylenediamine, benzotriazole, benzothiazole, tolylbenzotriazole, hydroxybenzotriazole, and morpholine; The polyol is selected from at least one of ethylene glycol, glycerol, propylene glycol, diethylene glycol, and isohexylene glycol.

6. The plasma cutting protection liquid according to claim 1, characterized in that: The leveling agent is selected from at least one of polyoxyethylene alkyl esters, alkyl glucosides, polyoxyethylene sorbitol esters, alkylphenol polyoxyethylene ethers, polyoxyethylene alkylamines, polyoxyethylene castor oil, polyoxyethylene sorbitol, alkyl glucosides, and fatty amide betaine.

7. The plasma cutting protection liquid according to claim 1, characterized in that: The plasticizer is selected from at least one of diethyl phthalate, dibutyl phthalate, di(2-ethylhexyl) phthalate, diisononyl phthalate, diisodecyl phthalate, dioctyl adipate, dioctyl fumarate, dioctyl succinate, tri(2-ethylhexyl) phosphate, and triphenyl phosphate.

8. The plasma cutting protection liquid according to claim 1, characterized in that: The organic solvent is selected from at least one of methanol, ethanol, propanol, isopropanol, propylene glycol methyl ether, dipropylene glycol methyl ether, ethylene glycol methyl ether, ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol ethyl ether, and diethylene glycol ethyl ether.

9. Use of the plasma cutting protection liquid according to any one of claims 1 to 8 in chip plasma cutting.

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