Plasma cutting protection liquid and application thereof

Abstract

The invention discloses a plasma cutting protection liquid and application thereof, and the plasma cutting protection liquid is prepared from the following components in parts by mass: 5 to 12 parts of water-soluble resin, 1 to 5 parts of polymer electrolyte, 0.05 to 0.25 part of corrosion inhibitor, 0.01 to 0.1 part of flatting agent, 0.01 to 0.1 part of plasticizer, 5 to 10 parts of organic solvent and 50 to 80 parts of ultrapure water. Wherein the polymer electrolyte is used for adsorbing and conducting metal ions to migrate towards the direction far away from the surface of the wafer, so that the metal ions are not in contact with the metal bonding structure. The polymer electrolyte adopted in the invention has strong adsorbability and can tightly adsorb metal ions, so that the metal ions preferentially migrate from the bottom of the film layer to the top of the film layer along a molecular chain of the polymer electrolyte, and the problem that the metal ions migrate and separate out along the surface of the chip is avoided.

Description

Technical Field

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

[0002] During the plasma wafer cutting process, it is necessary to apply a cutting protection liquid on the wafer surface so that the plasma beam can penetrate the exposed cutting path to cut the wafer and obtain chips. The bonding between different chips can be completed by setting multiple metal contact points on the chip, but when the cutting protection liquid is directly applied on the wafer, the protection liquid wraps around the metal electrode structure (Pad) and corrodes it to produce metal ions. The metal ions migrate and reduce in the liquid environment formed by the cutting protection liquid, and then precipitate on the chip surface again to form metal dendrites, thereby affecting the cleanliness of the chip surface. Summary of the invention

[0003] Purpose of application: This application provides a plasma cutting protection liquid 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, which is used to be coated on the surface of a wafer, wherein the surface of the wafer includes a plurality of metal electrode structures, wherein the metal electrode structures can be corroded, and free metal ions are formed in the plasma cutting protection liquid. The plasma cutting protection liquid includes the following components 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 are not in contact with the metal electrode structure.

[0006] In some embodiments, the polymer electrolyte has a structural formula as shown below:

[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 20000 to 100000; 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 at least one selected from monoethanolamine, diethanolamine, triethanolamine, dimethylethanolamine, ethylenediamine, benzotriazole, benzothiazole, methyl benzotriazole, 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 glucosides, polyoxyethylene sorbitol esters, alkylphenol polyoxyethylene ethers, polyoxyethylene alkylamines, polyoxyethylene castor oil, polyoxyethylene sorbitol, alkyl glucosyl esters, and fatty amide betaines.

[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 be coated on the surface of a wafer, the surface of the wafer includes a plurality of 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 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 in a direction away from the wafer surface so that the metal ions do not contact the metal electrode structure. The polymer electrolyte used in the present application has strong adsorption properties and can tightly adsorb metal ions, so that the metal ions preferentially migrate along the polymer electrolyte molecular chains from the bottom of the membrane layer to the top of the membrane layer. Since the polymer electrolyte has a high ion density and lower resistance, the metal ions will preferentially migrate along the lines with lower resistance, which avoids the problem of metal ions migrating and precipitating along the surface of the chip. In addition, in the present 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 technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

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

[0025] Figure 2 It is a 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 technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the embodiments of the present application and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present 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", are specifically 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 in the form of a range; it should be understood that the description in the form of a range is only for convenience and simplicity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values ​​within the range. For example, it should be considered that the range description from 1 to 6 has 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 are applicable regardless of the range. In addition, whenever a numerical range is indicated in this article, it is meant to include any quoted numbers (fractions or integers) 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 parts 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 the ultra-high-density Cu-Cu hybrid bonding technology, which is to tightly fit single chips with different functions to each other through the 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] In order to achieve high-quality hybrid bonding, it is necessary to ensure that the Cu Pad surface of the bonded chip has ultra-high cleanliness, that is, the number of particles larger than 0.12μm is less than 10. In order to meet this requirement, plasma cutting technology must be used when cutting the wafer into independent chips, because the cutting debris generated by the blade wheel and the silicon slag generated by laser cutting will make the number of particles on the chip surface not meet the requirements. Plasma cutting etches and cuts the substrate through plasma gas, and does not produce any debris or slag. It is a pollution-free chip cutting technology.

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

[0034] Therefore, it is necessary to develop a plasma cutting protection liquid to solve the problem of Cu dendrites generated during plasma cutting.

[0035] An embodiment of the present application provides a plasma cutting protection liquid, which is used to be coated on the surface of a wafer. The surface of the wafer includes multiple metal electrode structures. The metal electrode structures can be corroded to form free metal ions 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; wherein 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.

[0036] It can be understood that the metal electrode structure can be understood as the Cu Pad on the surface of the bonding chip. The Cu Pad refers to the copper (Cu) surface of the bonding chip, which is the part used to connect with other metals during the bonding process. When the chip surface is coated with plasma cutting protection liquid, the cutting protection liquid will wrap the metal bonding structure and corrode the metal bonding structure, thereby generating metal ions in the cutting protection liquid. Specifically, for the Cu Pad part, the metal ions generated are copper ions. For further reference, Figure 1 When copper ions are precipitated from a Cu Pad, they will migrate laterally in the protection solution to the vicinity of the adjacent Cu Pad with a high potential, and be reduced to Cu elemental, i.e., Cu dendrites, at the Cu Pad. In this embodiment, by adding a polymer electrolyte to the cutting protection solution, the migration path of the copper ions can be changed. For further information, see Figure 2, copper ions preferentially migrate longitudinally from the bottom to the top of the membrane along the polymer electrolyte molecular chain, and will not migrate laterally toward other Cu Pad directions. At this time, the copper ions are located far away from the chip surface and cannot contact the Cu Pad, which can greatly reduce the generation of Cu dendrites. Since the polymer electrolyte has a high ion density and lower resistance, metal ions will preferentially migrate along the lines with lower resistance, which avoids the problem of metal ions migrating and precipitating along the chip surface.

[0037] Furthermore, in this embodiment, the polymer electrolyte is added to the 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 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.

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

[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; the third step, polymerization of sulfonated 3-alkylthiophene. Taking 3-octylthiophene as an example, the specific process of 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 the addition time is controlled within 30 minutes to ensure that the temperature remains between 0-5°C; after the addition is completed, continue to stir and react in the ice-water bath for 2 hours; after the reaction is completed, use a separatory funnel to separate the organic layer and the aqueous layer, and 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 into a three-necked flask; slowly add 3-bromothiophene, and reflux for 2 hours under stirring to generate 3-thienylmagnesium bromide; slowly add 1-bromooctane to the reaction mixture, and continue to reflux for 4 hours under nitrogen protection; 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 3 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; under stirring, use a separatory funnel to slowly drop chlorosulfonic acid into the flask, and control the dropping time within 30 minutes to ensure that the temperature remains at 0-5°C; after the dropping is completed, continue to stir and react in the ice-water bath for 2 hours; after the reaction is completed, slowly add 20 mL of ice water to perform a hydrolysis reaction to obtain a sulfonated product solution.

[0053] In an ice-water bath, slowly add the sulfonated product solution dropwise to the sodium hydroxide solution, control the dropping speed to prevent violent reaction; after the dropwise addition is completed, continue to stir the reaction at room temperature for 1 hour; use a separatory funnel to separate the organic layer and the aqueous layer, and wash the organic layer with dichloromethane 3 times, each time with 20 mL; collect the aqueous layer, and adjust the pH to neutral with concentrated hydrochloric acid to precipitate the sodium sulfonate product; collect the solid product by filtration, and dry it 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] Add 3-octylthiophene monomer containing sodium sulfonate group and chloroform into a three-necked flask, stir to dissolve; add ferric bromide as a catalyst; install a reflux condenser, and reflux reaction at 80°C for 24 hours; after the reaction is completed, cool to room temperature, pour the reaction mixture into methanol, and precipitate a polymer; collect the solid polymer by filtration, and dry it in a vacuum drying oven to obtain the target polymer electrolyte.

[0057] It is understandable that polymer electrolytes with other structures can be prepared by using a preparation method similar to the above.

[0058] In some embodiments, the number average molecular weight of the polymer electrolyte is in the range of 20000 to 100000. For example, the number average molecular weight can be any one of 20000, 25000, 30000, 35000, 40000, 45000, 50000, 60000, 70000, 80000, 90000, 100000 or a range between any two values. Within this range, the polymer electrolyte can be guaranteed to have the ability to adsorb electron cores while improving its compatibility in the water-soluble resin, further promoting the uniform distribution of the polymer electrolyte in the entire 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 acrylic acid and maleic acid copolymer, sodium polystyrene sulfonate, and sodium salt of acrylic acid and sodium vinyl sulfonate copolymer. It is understood that the water-soluble resin is the base material of the protective liquid, as long as it is soluble in a solvent such as water and can form a transparent film layer after spin coating and drying.

[0060] In some embodiments, the number average molecular weight of the water-soluble resin ranges from 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 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 acid, nitrogen-containing organic compound and polyol. The corrosion inhibitor is used to prevent other metal structures on the surface of the wafer, 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 includes an amine compound or an azole compound, selected from at least one of monoethanolamine, diethanolamine, triethanolamine, dimethylethanolamine, ethylenediamine, benzotriazole, benzothiazole, methyl benzotriazole, 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 betaine. It is understood that the leveling agent is used to improve the uniformity of the protective liquid film on the wafer surface. Any substance that can be added to the cutting protective liquid to reduce the surface tension to within 40mM / 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 of the film layer 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 also provides a method for preparing a plasma cutting protection liquid, comprising the following steps:

[0074] Weigh 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, and 50-80 parts of ultrapure water respectively; stir and mix the above components until 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. 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 values.

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

[0078] In some embodiments, a method for using a plasma cutting protection liquid 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 a suitable range of fluctuations (for example, the molecular weight can be measured by various viscosity methods).

[0085] Example 1

[0086] Provided is a plasma cutting protection liquid, comprising: a water-soluble resin, a polymer electrolyte, a corrosion inhibitor, a leveling agent, a plasticizer, an organic solvent and ultrapure water; weighing each component in its respective amount, stirring at 25° C. at a speed of 300 rpm for 3 hours, to obtain the plasma cutting protection liquid. The specific substances and the number of parts of each component 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] Provided is a plasma cutting protection liquid, comprising: a water-soluble resin, a polymer electrolyte, a corrosion inhibitor, a leveling agent, a plasticizer, an organic solvent and ultrapure water; weighing each component in its respective amount, stirring at 25° C. at a speed of 300 rpm for 3 hours, to obtain the plasma cutting protection liquid. The specific substances and the number of parts of each component 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] Provided is a plasma cutting protection liquid, comprising: a water-soluble resin, a polymer electrolyte, a corrosion inhibitor, a leveling agent, a plasticizer, an organic solvent and ultrapure water; weighing each component in its respective amount, stirring at 25° C. at a speed of 300 rpm for 3 hours, to obtain the plasma cutting protection liquid. The specific substances and the number of parts of each component 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] Provided is a plasma cutting protection liquid, comprising: a water-soluble resin, a polymer electrolyte, a corrosion inhibitor, a leveling agent, a plasticizer, an organic solvent and ultrapure water; weighing each component in its respective amount, stirring at 25° C. at a speed of 300 rpm for 3 hours, to obtain the plasma cutting protection liquid. The specific substances and the number of parts of each component 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 liquid 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 25° C. at a speed of 300 rpm for 3 hours to obtain the plasma cutting protection liquid. The specific substances and the number of parts of each component 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] Provided is a plasma cutting protection liquid, comprising: a water-soluble resin, a polymer electrolyte, a corrosion inhibitor, a leveling agent, a plasticizer, an organic solvent and ultrapure water; weighing each component in its respective amount, stirring at 25° C. at a speed of 300 rpm for 3 hours, to obtain the plasma cutting protection liquid. The specific substances and the number of parts of each component 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] Provided is a plasma cutting protection liquid, comprising: a water-soluble resin, a polymer electrolyte, a corrosion inhibitor, a leveling agent, a plasticizer, an organic solvent and ultrapure water; weighing each component in its respective amount, stirring at 25° C. at a speed of 300 rpm for 3 hours, to obtain the plasma cutting protection liquid. The specific substances and the number of parts of each component 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 liquid 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 liquid. The specific substances and the number of parts of each component 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. Its specific components include: 10 parts of water-soluble resin, 0.15 parts of corrosion inhibitor, 0.06 parts of leveling agent, 0.04 parts of plasticizer, 8 parts of 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. For specific test data, see Table 2.

[0115] Table 2

[0116] Presence or absence of Cu dendrites Example 1 none Example 2 none Example 3 none Example 4 none Example 5 none Example 6 none Example 7 none Example 8 none Comparative Example 1 have

[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 the plasma cutting protection liquid of Example 1 is coated. 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 coated in Comparative Example 1. Figure 4 It can be seen that a large amount of Cu single substance precipitated near the Cu Pad, resulting in dendrites. Therefore, in Examples 1-8, due to the use of polymer electrolytes, metal ions can be tightly adsorbed, so that metal ions preferentially migrate from the bottom of the film layer to the top of the film layer along the polymer electrolyte molecular chain, avoiding the problem of metal ions migrating and precipitating along the chip surface; while in Comparative Example 1, there is no polymer electrolyte, and the problem of metal ions migrating and precipitating on the chip surface cannot be avoided, so Cu dendrites are generated.

[0118] The above is a detailed introduction to the plasma cutting protective fluid and its application provided in the embodiments of the present application. Specific examples are used in the present 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. 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, used 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 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; 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 are not in contact with the metal electrode structure.

2. The plasma cutting protection liquid according to claim 1, characterized in that: 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.

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

4. 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.

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

6. 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 at least one selected from monoethanolamine, diethanolamine, triethanolamine, dimethylethanolamine, ethylenediamine, benzotriazole, benzothiazole, methyl benzotriazole, hydroxybenzotriazole, and morpholine; The polyol is selected from at least one of ethylene glycol, glycerol, propylene glycol, diethylene glycol, and isohexylene glycol.

7. 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 glucosyl esters, and fatty amide betaine.

8. 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.

9. 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.

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

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