KR20090124195A - Protective film composition for dicing a wafer - Google Patents

Abstract

PURPOSE: A protective film composition for dicing a wafer is provided to prevent the generation of thermally crosslinked materials by irradiation of laser during a dicing process, to suppress the lifting of a protective film, and to ensure excellent applicability and storage stability. CONSTITUTION: A protective film composition for dicing a wafer comprises at least one resin selected from polyethyloxazoline and polyvinylpyrrolidone; least one resin selected from the group consisting of water-soluble resin and single monomer of alcohols; a watersoluble surface active agent; water or a mixture of water and organic solvent as a solvent. At least one resin and component are included in a weight ratio of 1:9 ~ 7:3.

Description

Protective film composition for wafer dicing

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective film composition for wafer dicing excellent in thermal stability, coating properties, storage stability, and the like used in a dicing step of a semiconductor.

The wafer dicing process in the semiconductor device manufacturing process is a process of separating each of the listed devices by cutting a boundary surface called a street after the semiconductor lamination process is completed. The semiconductor product is completed by the chip manufacturing process after the cutting process is completed. do.

The wafer dicing process is changing in a direction reflecting this because the distance between the streets becomes narrower and the mechanical properties of the stacks become weaker as the semiconductor is integrated.

As the degree of integration of devices increases, polyimide, the main material for forming the insulating film on the top of the stack, may be broken or damaged during the wafer dicing process. Therefore, the wafer dicing process is also changed from a process of cutting a wafer by a blade to a process using a blade after drilling a wafer using a laser, and a process of cutting a wafer using only a laser is also introduced. However, in a laser dicing process using a laser, fume is generated and scattered by the heat of the laser, which causes a problem of contamination of the upper surface of the wafer.

In order to solve the problem, a known technique is applied to a water-soluble resin of polyvinyl alcohol, polyethylene glycol, and cellulose based on an upper surface of a wafer to form a protective film and to generate laser light. A processing method for irradiating is disclosed.

However, even with such a technique, if silicon gas is generated on the wafer cut surface by the heat of laser light, the phenomenon occurs in the wafer protective film. In addition, the fume is generated along with the silicon gas and accumulated between the excited protective film and the upper part of the wafer, and afterwards, even if the wafer protective film is washed with water, it does not wash out, which acts as a defect.

In addition, water-soluble resins have a disadvantage of poor thermal stability. Therefore, when the laser is irradiated during the laser dicing process, heat is generated inside, and thermal decomposition of water-soluble resin such as polyvinyl alcohol is generated by this heat. Crosslinking occurs during pyrolysis, and the thermally crosslinked material remains on the wafer top surface without being removed by washing with water after the laser ashing process.

Currently, the laser dicing process is generally a cutting process of cutting a wafer using a blade after a perforation process by laser irradiation. If the hardness of the wafer protective film is high during the wafer cutting process using the blade, the protective film is broken. Phenomenon occurs, which causes foreign matters generated during cutting into the cracks of the film. This is a water-insoluble material, and because it adheres to the upper portion of the wafer substrate, it acts as a defect without being washed off when washed with water.

In addition, the protective film for wafer dicing is generally formed by spin coating the protective film composition, but if the coating property is poor, the stability of the protective film is reduced and the process margin is reduced. Therefore, the coating property in the preparation of the protective film composition should also be considered.

The present invention is to solve the above problems of the prior art, it is excellent in thermal stability, no thermal cross-linking material is generated by the laser irradiation during the dicing process, excellent adhesion with the wafer and protective film during the laser dicing process It does not occur, the protective film having a suitable hardness does not occur, the protective film is not broken even after cutting with a blade after the punching by the laser, and provides a protective film composition for wafer dicing excellent in coating properties and storage stability For the purpose of

The present invention, at least one resin selected from polyethyloxazoline and polyvinylpyrrolidone; At least one component selected from the group consisting of water-soluble resins and single molecules of alcohols; Water-soluble surfactants; And it provides a protective film composition for wafer dicing comprising water or a mixture of water and an organic solvent as a solvent.

The protective film composition for wafer dicing of the present invention is excellent in thermal stability, does not generate thermal crosslinking material due to laser irradiation during the dicing process, and has excellent adhesive strength with the wafer, resulting in the lifting of the protective film during the laser dicing process. Does not occur, and a protective film having an appropriate hardness is not formed, so that the protective film is not broken during cutting. In addition, since the coating performance and storage stability of the wafer are excellent, the integration degree is increased in the dicing process of the manufacturing process of a semiconductor device. It can be used extensively.

The present invention, at least one resin selected from polyethyloxazoline and polyvinylpyrrolidone; At least one component selected from the group consisting of water-soluble resins and single molecules of alcohols; Water-soluble surfactants; And a protective film composition for wafer dicing comprising water or a mixture of water and an organic solvent as a solvent.

Conventionally, water-soluble resins such as polyvinyl alcohol (PVA), polyethylene glycol (PEG), cellulose-based resins, and polyacrylic acid (PAA) are used, but among them, water-soluble resins having a hydroxyl group or a carboxylic acid group that dissolve well in water. Resins are susceptible to heat or produce crosslinking byproducts upon thermal decomposition.

However, polyethyloxazoline and polyvinylpyrrolidone, which are water-soluble resins used in the composition of the present invention, have not only excellent thermal stability but also excellent solubility in water.

It is preferable that the protective film composition for wafer dicing of this invention contains polyethyloxazoline or the mixture of polyethyloxazoline and polyvinylpyrrolidone.

As an example of polyethyloxazoline, poly (2-ethyl-2-oxazoline) is known under the trade name Aquazole, which has good solubility in water and excellent thermal stability. When the weight loss is measured in a thermogravimetric analyzer (TGA) at a temperature rising rate of 10 ° C./min under a nitrogen atmosphere, weight loss starts to appear at 350 ° C. or higher, and decomposition occurs rapidly around 380 ° C. However, no crosslinking accompaniment is made during decomposition, so that no defects are formed that do not dissolve in water.

Polyvinylpyrrolidone also has good solubility in water and excellent thermal stability. When the weight loss is measured in a thermogravimetric analyzer (TGA) at a temperature rising rate of 10 ° C./min under a nitrogen atmosphere, weight loss starts to appear around 300 ° C. and decomposition rapidly occurs around 400 ° C. However, it does not form a crosslinked accompaniment during decomposition, and thus does not produce a defect that does not dissolve in water.

In the protective film composition for wafer dicing of the present invention, at least one component selected from the group consisting of single molecules of the above water-soluble resins and alcohols is used for improving substrate adhesion and hardness of the protective film. Examples of the water-soluble resin include polyvinyl alcohol, polyethylene glycol (PEG), cellulose, polyacrylic acid (PAA), and the like. Examples of the single molecules of the alcohols include monoethylene glycol, trisethylene glycol, and tetraethylene. Glycol, pentaerythritol, trismethylpropanol and the like.

The polyvinyl alcohol is a water-soluble resin and has good solubility in water and has excellent adhesion to wafers. Therefore, when a mixture of polyethyl oxazoline and polyvinyl alcohol is used, the adhesion of the protective film composition for wafer dicing can be improved, thereby preventing the lifting of the protective film during laser irradiation. Polyvinyl alcohol has different solubility in water according to saponification and molecular weight, and storage stability after dissolution is also different. If the saponification degree of polyvinyl alcohol is 100%, the solubility in water is not good, and since the gelation proceeds after dissolving in water, the viscosity increases with time. For this reason, polyvinyl alcohol whose saponification degree is 87 to 90% can be used. Polyvinyl alcohol with 87% to 90% saponification can be used as a solution because there is no change in viscosity with time. In addition, the solubility and the stability with time appear different depending on the molecular weight, polyvinyl alcohol having a polymerization degree of 500 ~ 2,000 is excellent in solubility and storage stability. Therefore, in this invention, it is preferable to use polyvinyl alcohol whose saponification degree is 87 to 90% and a polymerization degree is 500 to 2,000.

However, since polyvinyl alcohol has poor thermal stability, it is preferable to use polyvinyl alcohol mixed with polyethyloxazoline or polyvinylpyrrolidone having excellent thermal stability, and at 250 ° C or lower, crosslinking by-products which are not dissolved by water are not produced. It can be used within the range.

In the protective film composition of the present invention, one or more components selected from the group consisting of one or more resins (based on solids) selected from the polyethyloxazoline and polyvinylpyrrolidone and the single molecules of the water-soluble resins and alcohols (the The water-soluble resin is based on a solid content) is preferably included in a weight ratio of 1: 9-7: 3, when included in the above range, preferred physical properties in thermal stability, adhesion to the wafer, protective film hardness, etc. appear.

In the protective film composition for wafer dicing of the present invention, the water-soluble surfactant serves to improve the coating property of the composition and to increase the storage stability.

In general, since the thickness of the protective film used in the laser dicing process is 1 μm or more, when the coating property of the protective film composition is not good, a difference in the film thickness between the center and the edge of the wafer occurs and the process margin is reduced. Therefore, the protective film composition of this invention improves the coating property of a composition by adding water-soluble surfactant. Examples of the water-soluble surfactant include polyether-modified alkylsiloxanes, polyether-modified polyalkylsiloxanes, polydimethyl siloxanes of polyether-modified hydroxy functional groups, polyether-polyester-modified hydroxy polyalkylsiloxanes, and nonionic polyacrylic-based water-soluble surfactants. Active agents, alcohol alkoxylates, polymeric fluorine-based water-soluble surfactants, and the like, and these may be used alone or in combination of two or more thereof.

In addition, the present inventors have found that the water-soluble surfactant also serves as a dispersant in the protective film composition so that gelation does not occur in the protective film composition over time. Therefore, the protective film composition of this invention contains water-soluble surfactant, and it has not only the improvement of applicability | paintability but also the outstanding storage stability.

In the protective film composition of the present invention, the water-soluble surfactant is preferably included in 10 ~ 80ppm relative to the total weight of the solid content of the resin component contained in the composition, when included in the above range, the coating properties, storage stability of the protective film composition Preferable physical properties are shown, and the like is also preferable in terms of thermal stability, adhesion to wafers, protective film hardness, and the like.

Although the protective film composition for wafer dicing of the present invention uses water as a solvent, an organic solvent may be mixed and used to adjust the film thickness of the protective film composition, and to improve the coating property and storage stability. Examples of the organic solvent include isopropyl alcohol, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), alkyl carbonate-based butylene carbonate, propylene carbonate, glycerin carbonate, ethylene carbonate, and the like. . Such an organic solvent can be used 1 type or in mixture of 2 or more types.

In the organic solvent, propylene glycol monomethyl ether has excellent compatibility with water, so that it can be dissolved with water in any mixing ratio, but propylene glycol monomethyl ether acetate is dissolved in only 16 g or less with respect to 100 g of water. do.

In particular, when a mixture of organic solvents such as butylene carbonate, propylene carbonate, glycerin carbonate and ethylene carbonate having a high polarity is used in combination, it has a favorable effect in terms of storage stability and coating property.

The ethylene carbonate is well soluble in solid or water at room temperature, glycerin carbonate can be dissolved in water in any mixing ratio. However, butylene carbonate and propylene carbonate should be used within this range because the solubility in water is less than 10% and 25% at room temperature, respectively.

In the protective film composition of the present invention, the solvent is added to adjust the viscosity of the total composition to 10 ~ 100 cP. When the viscosity of a protective film composition is in the said range, it shows the outstanding applicability | paintability, In addition, preferable physical property also shows in storage stability, wafer adhesiveness, the hardness of a protective film, etc.

The protective film composition for wafer dicing of the present invention may further include one or more additives known in the art to improve performance.

In particular, the protective film composition for wafer dicing of the present invention may further include an antifoaming agent as an additive in order to suppress the foaming of the solution, and such antifoaming agents include polysiloxane, polyalkylsiloxane, fluorosilicone polymer and the like.

The present invention also relates to a semiconductor device manufactured using the above protective film composition for wafer dicing. The semiconductor device according to the present invention is completely protected by the wafer dicing protective film according to the present invention even when dicing a wafer using a laser, a blade, etc., and the cleaning of the protective film is also easy, so there is no defect. It is characterized by being manufactured in a state.

Hereinafter, the present invention will be described in more detail using examples. However, the following examples are provided to illustrate the present invention, and the present invention is not limited to the following examples and may be variously modified and changed.

Example  1 to 5 and Comparative example  1 to 4: wafer For dicing  Preparation of Protective Film Composition

Example  One

5 g of polyethyloxazoline (trade name Aquazol, polymerization degree 50), 5 g of polyvinyl alcohol (polymerization degree 500, saponification degree 87 to 90%), surfactant (BYK-337, manufactured by BYK) and antifoaming agent in a mixing tank equipped with a stirrer (BYK-025, manufactured by BYK Co., Ltd.), 30 ppm each was added to the sum of the solid content of polyethyloxazoline and polyvinyl alcohol, and the solution was added at a temperature of 60 cP while adding water as a solvent. By stirring at a speed of 500rpm for a time to prepare a protective film composition for wafer dicing.

Example  2

3 g of polyethyloxazoline (trade name Aquazol, polymerization degree 50), 3 g of polyvinylpyrrolidone (polymerization degree 1200), 4 g of polyvinyl alcohol (polymerization degree 1700, saponification degree 87 to 90%) in a mixing tank equipped with a stirrer 30 ppm each of the activator (BYK-337, manufactured by BYK) and the antifoaming agent (BYK-025, manufactured by BYK) were added to the sum of the contents of the solid content of polyethyloxazoline, polyvinylpyrrolidone and polyvinyl alcohol. After adding water so that the viscosity of the solution was 60 cP, and stirred at a speed of 500 rpm for 1 hour at room temperature to prepare a protective film composition for wafer dicing.

Example  3

2 g of polyethyloxazoline (trade name Aquazol, polymerization degree 50), 2 g of polyvinylpyrrolidone (polymerization degree 1200), 6 g of polyvinyl alcohol (polymerization degree 1700, saponification degree 87 to 90%) in a mixing tank equipped with a stirrer (BYK-337, manufactured by BYK) and the antifoaming agent (BYK-025, manufactured by BYK) are charged 30 ppm each for the sum of the contents of the solid polyethyloxazoline, polyvinylpyrrolidone, and polyvinyl alcohol, and water is used as the solvent. While adding the solution so that the viscosity of the solution is 60cP, and stirred at a speed of 500rpm for 1 hour at room temperature to prepare a protective film composition for wafer dicing.

Example  4

7 g of polyethyl oxazoline (trade name Aquasol, polymerization degree 500), 3 g of polyvinyl alcohol (polymerization degree 500, saponification degree 87 to 90%), surfactant (BYK-337, manufactured by BYK) and antifoaming agent in a mixing tank equipped with a stirrer (BYK-025, manufactured by BYK Co., Ltd.), 30 ppm each was added to the sum of the solid content of polyethyloxazoline and polyvinyl alcohol as solids, and water was added to the solvent to add the solution to a viscosity of 60 cP, and then at room temperature. A protective film composition for wafer dicing was prepared by stirring at a speed of 500 rpm for 1 hour.

Example  5

3 g of polyethyloxazoline (trade name Aquazol, polymerization degree 500), 7 g of polyvinyl alcohol (polymerization degree 1700, saponification degree 87 to 90%), 1 g of trisethylene glycol (TEG), 0.3 g of butylene carbonate in a mixing tank equipped with a stirrer , 30 ppm each of the surfactant (BYK-337, manufactured by BYK) and the antifoaming agent (BYK-025, manufactured by BYK) were added to the sum of the content of solid polyoxazoline and polyvinyl alcohol, and water was added as a solvent. After the solution was added to have a viscosity of 60 cP, the protective film composition for wafer dicing was prepared by stirring at a speed of 500 rpm for 1 hour at room temperature.

Comparative example  One

10 g of polyvinyl alcohol (polymerization degree 1700, saponification degree 87 to 90%) and water were added to the mixing tank equipped with a stirrer to add a solution to a viscosity of 60 cP, followed by stirring at a speed of 500 rpm for 1 hour at room temperature. To prepare a protective film composition for wafer dicing.

Comparative example  2

9 g of polyvinyl alcohol (polymerization degree 1700, saponification degree 87 to 90%), 1 g of polyethylene glycol (weight average molecular weight 700) and BYK-337 are 300 ppm with respect to the sum of polyvinyl alcohol and polyethylene glycol as solids Was added, the solution was added with a viscosity of 60 cP while adding water as a solvent, and then stirred at a speed of 500 rpm for 1 hour at room temperature to prepare a protective film composition for wafer dicing.

Comparative example  3

9 g of polyvinyl alcohol (polymerization degree of 1700, saponification degree of 87 to 90%), 1 g of pentaerithritol, and BYK-337 are added to the sum of polyvinyl alcohol and pentaerythritol as solids. 300 ppm was added, and water and propylene glycol monomethyl ether (PGME) were added at a ratio of 70/30 (w / w) as a solvent to add a viscosity of 60 cP, followed by a rate of 500 rpm for 1 hour at room temperature. It was stirred to prepare a protective film composition for wafer dicing.

Comparative example  4

8 g of polyvinyl alcohol (polymerization degree 1700, saponification degree 87 to 90%), 1 g polyethylene glycol (weight average molecular weight 700), 1 g pentaerythritol, 1 g of solvent, water and propylene glycol monomethyl ether (PGME) ) Was added at a rate of 70/30 (w / w) so that the viscosity of the solution was 60 cP, and then stirred at 500 rpm for 1 hour at room temperature to prepare a protective film composition for wafer dicing.

Test Example 1: strip speed measurement test

Samples were prepared by spin coating the samples of the Examples and Comparative Examples on a 4 inch silicon oxide substrate and adjusting the spin rate (rpm) so that the film thickness dried at 110 ° C. for 15 minutes was 1 μm. These samples were used to measure the rate of stripping into water on a DRM machine. The unit of measurement is expressed as the film thickness removed per second. The test results are shown in Table 1 below.

◎: 1000 nm / s or more

○: 800 to 1000nm / s

△: 500 to 800 nm / s

×: 500 nm / s or less

Test Example 2: coating performance measurement test

Samples were prepared by spin coating the samples of Examples and Comparative Examples on a 4 inch silicon oxide substrate and adjusting the spin rate (rpm) so that the film thickness was dried at 110 ° C. for 15 minutes to 1 μm. Thereafter, the film thicknesses of 2 cm and 4 cm apart from each other in the center and the center of the wafer were measured, and the standard deviation was confirmed to confirm the coating performance of the protective film composition for wafer dicing. The test results are shown in Table 1 below.

◎: 1% or less

○: 1 to 2%

△: 2 to 4%

×: 4% or more

Test Example 3: storage stability test

While keeping the samples of the Examples and Comparative Examples at room temperature, the viscosity measurement and coating properties were measured every week to determine whether the change in physical properties over time. The test results are shown in Table 1 below.

◎: Stable for 16 weeks or more

○: stable for more than 12 weeks

△: stable for more than 8 weeks

×: stable in less than 8 weeks

Test Example 4: adhesion measurement test

Samples were prepared by spin coating a sample of the above Examples and Comparative Examples on a 4 inch silicon oxide substrate and adjusting the spin rate (rpm) so that the film thickness dried at 110 ° C. for 15 minutes was 1 μm. Thereafter, a crosscut test (tapping test) was conducted based on the experimental method of JIS K5600-5-6. The test results are shown in Table 1 below.

◎: Number of fallen grids (0)

○: number of grids dropped (1 to 5)

△: number of fallen grids (5-10 pieces)

×: number of fallen grids (10 or more)

Test Example  5: pencil hardness measurement test

Samples of Examples and Comparative Examples were coated on a 4 inch silicon oxide substrate, and a sample was prepared by adjusting the spin speed (rpm) so that the film thickness dried at 110 ° C. for 15 minutes was 1 μm. After that, the pencil hardness was measured according to the experimental method of JID D 0202. The test results are shown in Table 1 below.

Test Example 6: Thermal stability  Test

After spin coating the samples of Examples and Comparative Examples on a 4 inch silicon oxide substrate, a sample was prepared by adjusting the spin rate (rpm) so that the film thickness dried at 110 ° C. for 15 minutes was 1 μm. Thereafter, the mixture was left at 250 ° C. for 10 minutes in a hot air dryer, and then washed with water. This is a test to check whether pyrolytic crosslinking material that is insoluble in water is generated by heat. The test results are shown in Table 1 below.

◎: Stripped clean

○: fine particle present

△: many unstriped parts

× not stripped at all

Strip speed Coating performance Storage stability Adhesion Pencil hardness Thermal stability Example 1 ◎ ◎ ◎ ○ 9H ◎ Example 2 ◎ ◎ ◎ ◎ 7H ◎ Example 3 ◎ ◎ ◎ ◎ 9H ○ Example 4 ◎ ◎ ◎ ○ 7H ◎ Example 5 ◎ ◎ ◎ ◎ 5H ◎ Comparative Example 1 △ × △ ◎ 9H △ Comparative Example 2 ○ ◎ ○ × H △ Comparative Example 3 △ ○ △ × H △ Comparative Example 4 ○ ○ ○ × H △

Claims (10)

At least one resin selected from polyethyloxazoline and polyvinylpyrrolidone; At least one component selected from the group consisting of water-soluble resins and single molecules of alcohols; Water-soluble surfactants; And a water or a mixture of water and an organic solvent as a solvent. The method according to claim 1, wherein the polyethyloxazoline and at least one component selected from the group consisting of polyvinylpyrrolidone (solid content basis) and the water-soluble resin and a single molecule of alcohols (the water-soluble Resin is based on solids) in a weight ratio of 1: 9-7: 3; The water-soluble surfactant is included in 10 ~ 80ppm relative to the total weight of the solid content of the resin component included in the composition; The solvent is a protective film composition for a wafer dicing, characterized in that included in the range that the viscosity of the entire composition is 10 ~ 100 cP. The protective film composition for wafer dicing according to claim 1, wherein at least one resin selected from polyethyloxazoline and polyvinylpyrrolidone is polyethyloxazoline. The method according to claim 1, wherein the water-soluble resin is polyvinyl alcohol, polyethylene glycol (PEG), cellulose, and polyacrylic acid (PAA), the single molecules of the alcohols are monoethylene glycol, trisethylene glycol, tetraethylene glycol, It is pentaerythritol and trismethyl propanol, The protective film composition for wafer dicing characterized by the above-mentioned. The method according to claim 1, wherein the water-soluble surfactant is polyether modified alkylsiloxane, polyether modified polyalkylsiloxane, polydimethyl siloxane of polyether modified hydroxy functional group, polyether-polyester modified hydroxy polyalkylsiloxane, non-phosphorous polyacrylic type A water-soluble surfactant, alcohol alkoxylate, and a polymeric fluorine-based water-soluble surfactant, at least one member selected from the group consisting of a protective film composition for wafer dicing. The method according to claim 1, wherein at least one component selected from the group consisting of the water-soluble resin and the monomolecule of alcohols is polyvinyl alcohol, and the polyvinyl alcohol has a degree of saponification of 87 to 90% and a degree of polymerization of 500 to 2,000. A protective film composition for wafer dicing characterized by the above-mentioned. The method according to claim 1, wherein at least one resin selected from polyethyloxazoline and polyvinylpyrrolidone is polyethyloxazoline, and at least one component selected from the group consisting of single molecules of the water-soluble resin and alcohols is A polyvinyl alcohol having a degree of saponification of 87 to 90% and a degree of polymerization of 500 to 2,000, and a protective film composition for wafer dicing. The method of claim 1, wherein the solvent is a mixture of water and an organic solvent, the organic solvent is isopropyl alcohol, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), butylene carbonate, propylene carbonate, A protective film composition for wafer dicing, characterized in that at least one selected from the group consisting of glycerin carbonate and ethylene carbonate. The protective film composition for wafer dicing according to claim 7 or 8, wherein the organic solvent is at least one selected from the group consisting of butylene carbonate, propylene carbonate, glycerin carbonate, and ethylene carbonate. A semiconductor device manufactured using the protective film composition for wafer dicing of claim 1.