KR20090124194A - Protective film composition for dicing a wafer - Google Patents

Abstract

PURPOSE: A protective film composition for dicing a wafer is provided to prevent thermo-crosslinking materials from being generated by irradiation of laser during a dicing process, and to avoid defects caused by the lifting of a protective film. CONSTITUTION: A protective film composition for dicing a wafer comprises based on the total weight of composition except for solvent, at least one resin 10~70 weight% (solid standard) selected from polyethyloxazoline and polyvinylpyrrolidone; at least one component 30~90 weight% (the water-soluble resin is the solid standard) selected from the group consisting of a consisting of a water-soluble resin and a single monomer of alcohols; and water or a mixture of water and organic solvent.

Description

Protective film composition for wafer dicing

The present invention relates to a protective film composition for wafer dicing excellent in thermal stability 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 non-aqueous 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.

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 is an object of the present invention to provide a protective film composition for wafer dicing in which no floating phenomenon occurs and the protective film is not broken even after cutting with a blade after drilling with a laser by forming a protective film having an appropriate hardness.

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; 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, and because the coating performance on the wafer is excellent, it is widely used in the dicing process of the manufacturing process of the semiconductor device which is increasing in density. Can be.

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; 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.

Poly (2-ethyl-2-oxazoline) as the polyethyloxazoline 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 of the present invention, at least one resin selected from polyethyloxazoline and polyvinylpyrrolidone may be included in an amount of 10 to 70% by weight based on the total weight of the composition excluding the solvent. When included in the above range, desirable physical properties are exhibited in thermal stability, adhesion to wafers, hardness of the protective film, and the like.

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, tetra Ethylene glycol, pentaerythritol, trismethyl propanol, etc. are mentioned.

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 polyethyloxazoline 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, at least one component selected from the group consisting of single molecules of the water-soluble resin and alcohols may be included in an amount of 30 to 90 wt% based on the total weight of the composition excluding the solvent. The water-soluble resin in the above is based on the solid content. When included in the above ranges, desirable physical properties appear in adhesion to the wafer, protective film hardness, and the like.

In the protective film composition for wafer dicing of the present invention, water is used as the solvent, but an organic solvent may be mixed and used to increase the film thickness of the protective film composition or to improve applicability. Examples of the organic solvent include isopropyl alcohol, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and the like, and these organic solvents may be used alone or in combination of two or more thereof. have. Among the organic solvents, propylene glycol monomethyl ether may be most preferably used because of its excellent compatibility with water. This is because propylene glycol monomethyl ether is soluble in water and in any mixing ratio, but propylene glycol monomethyl ether acetate has solubility that only 16 g or less is dissolved in 100 g of water.

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, and preferable physical property also appears in 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 for improving performance.

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 that there is no defect. Characterized in that manufactured.

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

Into a mixing tank equipped with a stirrer, 5 g of polyethyloxazoline (trade name Aquazol, polymerization degree 50), 5 g of polyvinyl alcohol (polymerization degree 500, saponification degree 87 to 90%), and water were added as a solvent and the viscosity of the solution was 60 cP. After the addition, the mixture was stirred at a speed of 500 rpm for 1 hour at room temperature 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%) and a solvent in a mixing tank equipped with a stirrer The solution was added with a viscosity of 60 cP while adding water, and then stirred at a speed of 500 rpm for 1 hour at room temperature to prepare a protective film composition for wafer dicing.

Example  3

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%) and a solvent in a mixing tank equipped with a stirrer Water and propylene glycol monomethyl ether (PGME) was added at a ratio of 70/30 (w / w) to add a viscosity of 60 cP, followed by stirring at 500 rpm for 1 hour at room temperature for wafer dicing. A protective film composition was prepared.

Example  4

7 g of polyethyl oxazoline (trade name Aquazol, polymerization degree 500), 3 g of polyvinyl alcohol (polymerization degree 500, saponification degree 87 to 90%) in a mixing tank equipped with a stirrer, and water and propylene glycol monomethyl ether (PGME) as a solvent. ) Was added at a rate of 70/30 (w / w) so that the viscosity of the solution was 60 cP, and then stirred at a speed of 500 rpm for 1 hour at room temperature to prepare a protective film composition for wafer dicing.

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%) in a mixing tank equipped with a stirrer, and water and propylene glycol monomethyl ether (PGME) as a solvent Was added at a rate of 70/30 (v / v) while adding the solution to have a viscosity of 60 cP, 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  One

10 g of polyvinyl alcohol (polymerization degree 1700, saponification degree 87 to 90%), and water were added as a solvent to add a viscosity of 60 cP to a mixing tank equipped with a stirrer, and then at a speed of 500 rpm for 1 hour at room temperature. By stirring, a protective film composition for wafer dicing was prepared.

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 water were added as a solvent to add a viscosity of 60 cP to a mixing tank equipped with a stirrer. , And 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 1700, saponification degree 87 to 90%), 1 g pentaerithritol, and water and propylene glycol monomethyl ether (PGME) as a solvent were mixed in a mixing tank equipped with a stirrer. v / v) was added at a rate of 60 cP while the solution was added at a rate of v / v, 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  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, and water and propylene glycol monomethyl ether ( PGME) was added at a rate of 70/30 (v / v) and added so that the viscosity of the solution was 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.

Test Example 1: coated wafer For dicing  Strip velocity measurement test with water of protective film composition

After spin-coating the sample of Example and Comparative Example on a 4 inch silicon oxide substrate, the sample was prepared by adjusting the spin rate (rpm) so that the film thickness dried at 110 ° C. for 15 minutes was 1 μm. These samples were measured at 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: wafer For dicing  Coating performance measurement test of protective film composition

After spin-coating the sample of Example and Comparative Example on a 4 inch silicon oxide substrate, the 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 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: pencil hardness test

After spin coating the sample of the Example and Comparative Example on a 4 inch silicon oxide substrate, the sample was prepared by adjusting the spin rate (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 4: adhesion measurement test

After spin-coating the sample of Example and Comparative Example on a 4 inch silicon oxide substrate, the 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, 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: Thermal stability  Test

After spin-coating the sample of Example and Comparative Example on a 4 inch silicon oxide substrate, the 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 Pencil hardness Adhesion Thermal stability Example 1 ◎ ◎ 7H ◎ ◎ Example 2 ◎ ○ 9H ○ ◎ Example 3 ◎ ○ 9H ○ ◎ Example 4 ◎ ◎ 7H ◎ ◎ Example 5 ◎ ◎ 7H ◎ ◎ Comparative Example 1 △ × 9H ◎ △ Comparative Example 2 ○ ◎ H × △ Comparative Example 3 △ ○ H × △ Comparative Example 4 ○ ○ H × △

Claims (9)

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; And a water or a mixture of water and an organic solvent as a solvent. The method according to claim 1, 10 to 70% by weight (based on solids) of the at least one resin selected from the polyethyloxazoline and polyvinylpyrrolidone based on the total weight of the composition excluding the solvent and the single molecule of the water-soluble resin and alcohols 30 to 90% by weight of one or more components selected from the group consisting of (the water-soluble resin is based on solids); The viscosity of the whole composition is 10-100 cP, The protective film composition for wafer dicing characterized by the above-mentioned. 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 of claim 1, wherein the water-soluble resin is polyvinyl alcohol, polyethylene glycol (PEG), cellulose, and polyacrylic acid (PAA), and the single molecules of the alcohols are monoethylene glycol, trisethylene glycol, tetraethylene glycol, penta. It is erythritol and trismethyl propanol, The protective film composition for wafer dicing characterized by the above-mentioned. 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, wherein the organic solvent is selected from the group consisting of isopropyl alcohol, propylene glycol monomethyl ether acetate (PGMEA), and propylene glycol monomethyl ether (PGME). A protective film composition for wafer dicing characterized by being at least one species. The protective film composition for wafer dicing according to claim 7, wherein the organic solvent is propylene glycol monomethyl ether (PGME). The semiconductor device manufactured using the protective film composition for wafer dicing of any one of Claims 1-8.