TWI857986B - Protective film composition, manufacturing method of semiconductor device, and laser cutting method - Google Patents

Abstract

The present invention provides a protective film composition including: a water-soluble resin (A), a laser light absorbing agent (B), and a solvent (C), wherein the water-soluble resin (A) includes a polyvinylpyrrolidone-based water-soluble resin (A-1), and the polyvinylpyrrolidone-based water-soluble resin (A-1) has a K value of 75 or more and 150 or less. The protective film composition has the advantage of good leveling property.

Description

Protective film composition, method for manufacturing semiconductor device, and laser cutting method

The present invention relates to a protective film composition, a method for manufacturing a semiconductor device and a laser cutting method, and in particular to a protective film composition used for laser cutting of a semiconductor wafer, a method for manufacturing a semiconductor device processed by laser cutting, and a laser cutting method.

In the manufacturing process of semiconductor devices, semiconductor wafers with various devices stacked on them are cut and separated to obtain individual semiconductor chips. In recent years, laser cutting has been used as a cutting method. Laser cutting is a method of cutting an object into a desired shape by irradiating it with a laser, and can perform high-precision processing in a short time.

In laser cutting, after the substrate is irradiated with laser, the following situation occurs: the substrate absorbs the laser, the heat energy thereof causes the substrate to melt, and the heat melt (debris) adheres to the surface of the component. If the debris adheres to the surface of the component, the quality of the semiconductor chip is reduced. As a processing method for protecting the surface of the component from the influence of the debris, a processing method of forming a protective film on the surface of the substrate and irradiating laser light through the protective film has been proposed. As a protective film, a water-soluble protective film that can be washed and removed after laser cutting has been studied.

Specifically, Taiwan Patent Publication No. 201614017 discloses a protective film composition for laser cutting, which includes: a water-soluble resin, a resin capsule containing a laser light absorber, and an aqueous solvent.

However, the protective film composition described above has poor leveling properties and is therefore not accepted by the industry.

In view of the above problems, the present invention provides a protective film composition, which can improve the above problem of poor leveling.

The present invention provides a protective film composition, comprising: a water-soluble resin (A), a laser light absorber (B) and a solvent (C), wherein the water-soluble resin (A) comprises a polyvinyl pyrrolidone-based water-soluble resin (A-1), and the K value of the polyvinyl pyrrolidone-based water-soluble resin (A-1) is 75 to 150.

In one embodiment of the present invention, the water-soluble resin (A) further comprises a polyvinyl pyrrolidone-based water-soluble resin (A-2), and the K value of the polyvinyl pyrrolidone-based water-soluble resin (A-2) is 5 to 70.

In one embodiment of the present invention, the K value of the polyvinyl pyrrolidone-based water-soluble resin (A-1) is 80 to 140.

In one embodiment of the present invention, the K value of the polyvinyl pyrrolidone-based water-soluble resin (A-1) is 80 to 130.

In one embodiment of the present invention, the K value of the polyvinyl pyrrolidone-based water-soluble resin (A-2) is 10 to 65.

In one embodiment of the present invention, the K value of the polyvinyl pyrrolidone-based water-soluble resin (A-2) is 15 to 65.

In one embodiment of the present invention, based on the usage of the water-soluble resin (A) being 100 parts by weight, the usage of the polyvinyl pyrrolidone-based water-soluble resin (A-1) is 25 parts by weight to 65 parts by weight, and the usage of the polyvinyl pyrrolidone-based water-soluble resin (A-2) is 35 parts by weight to 75 parts by weight.

In one embodiment of the present invention, based on the usage of the water-soluble resin (A) being 100 parts by weight, the usage of the laser light absorber (B) being 1 part by weight to 30 parts by weight, and the usage of the solvent (C) being 500 parts by weight to 3000 parts by weight.

In one embodiment of the present invention, the protective film composition is used for laser cutting.

The present invention further provides a method for manufacturing a semiconductor device, comprising: a step of applying the above-mentioned protective film composition to a substrate to form a protective layer, a step of irradiating the substrate with laser light through the protective layer to perform laser cutting, and a step of washing the substrate after laser cutting to remove the protective layer from the substrate.

The present invention also provides a laser cutting method, comprising: a step of applying the above-mentioned protective film composition to a substrate to form a protective layer, a step of irradiating the substrate with laser light through the protective layer to perform laser cutting, and a step of washing the substrate after laser cutting to remove the protective layer from the substrate.

Based on the above, the protective film composition of the present invention contains a polyvinyl pyrrolidone-based water-soluble resin (A-1) having a specific K value range and a laser light absorber (B), and therefore, can improve the technical problem of poor leveling in the prior art.

Furthermore, the protective film composition according to the present invention contains a water-soluble laser light absorber in addition to the water-soluble resin. Therefore, the protective film formed on the wafer surface by applying and drying the protective film composition exhibits a high absorption of laser light, so when irradiated with laser light, it can be thermally decomposed in time along the street line and processed by laser. Therefore, it is possible to effectively avoid the situation where the protective film is peeled off due to the vapor pressure of the thermal decomposition product of the substrate formed by exposure to laser light. In addition, the water-soluble dyes and the like that are water-soluble laser light absorbers have a high affinity for the wafer surface. Therefore, the adhesion of the protective film is improved, and it is possible to effectively suppress the protective film from peeling off from the wafer surface, especially near the street line. Accordingly, by forming a protective film using the protective film composition of the present invention and performing laser cutting using laser light, it is possible to effectively prevent slag from being deposited on the cut wafer surface.

In addition, as a general laser light, a laser light with a wavelength of 355 nm is used. When cutting with such laser light, the amount of laser light absorber used is adjusted so that the g absorption coefficient k of the protective film (solid of the aforementioned protective film composition) is within the range of 3×10 ^-3 to 2.5×10 ^-1 abs‧L/g (abs: absorbance). In this way, uniform processing results can be achieved along the fine width of the street line.

In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below and described in detail as follows.

> Protective film composition > The present invention provides a protective film composition, including a water-soluble resin (A), a laser light absorber (B) and a solvent (C), and optionally an additive (D). The water-soluble resin (A) includes a polyvinyl pyrrolidone-based water-soluble resin (A-1), and optionally includes a polyvinyl pyrrolidone-based water-soluble resin (A-2) and other water-soluble resins (A-3). The following will describe in detail the various components of the protective film composition of the present invention. Water-soluble resin ( A )

The water-soluble resin (A) includes a polyvinyl pyrrolidone-based water-soluble resin (A-1) having a K value of 75 to 150, but from the perspective of improving leveling properties, it is better to use a polyvinyl pyrrolidone-based water-soluble resin (A-2) having a K value of 5 to 70, and other water-soluble resins (A-3) may be added as appropriate. Polyvinyl pyrrolidone-based water-soluble resin ( A-1 )

The K value of the polyvinyl pyrrolidone-based water-soluble resin (A-1) is in the range of 75 to 150, preferably 80 to 140, and more preferably 80 to 130.

The K value of a water-soluble resin is a value indicating the molecular weight obtained by the Fikentscher method, as shown in the following formula (1), and can be determined by the following measurement method. When the K value is less than 20, measure the viscosity of a 5% (g/100 mL) solution. When the K value is greater than 20, measure the viscosity of a 1% (g/100 mL) solution. The sample concentration is calculated by converting the dry matter. When the K value is greater than 20, accurately measure 1.0 g of the sample, place it in a 100 mL volumetric flask, add distilled water at room temperature, shake, and completely dissolve it. Add distilled water to make the solution exactly 100 mL. After placing the sample solution in a constant temperature bath (25±0.2℃) for 30 minutes, the viscosity is measured using an Uberoude viscometer. The time for the sample solution to flow between the two marking lines is measured. The average value is obtained by performing several measurements. In order to determine the relative viscosity, distilled water is also measured in the same way. The two obtained flow times are corrected according to the Hagenbach-Couette correction value.

···（1） In formula (1), Z is the relative viscosity (η _rel ) of the solution with concentration C, C is the concentration of the sample (%: g/100 mL). The relative viscosity η _rel is obtained by the following formula (2). η _rel = (flow time of solution) ÷ (flow time of water)···（2）

Specific examples of polyvinyl pyrrolidone-based water-soluble resins (A-1) include the following commercially available products: PITZCOL K-90 (K value = 88 to 100, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), PVP K-85 (K value = 83 to 88, manufactured by Nippon Catalyst Co., Ltd.), and PVP K-120 (K value = 114 to 130, manufactured by Nippon Catalyst Co., Ltd.). The polyvinyl pyrrolidone-based water-soluble resins (A-1) may be used alone or in combination of two or more.

Based on 100 parts by weight of the water-soluble resin (A), the amount of the polyvinyl pyrrolidone-based water-soluble resin (A-1) is 25 to 65 parts by weight, preferably 30 to 65 parts by weight, and more preferably 30 to 60 parts by weight. When the water-soluble resin (A) does not include the polyvinyl pyrrolidone-based water-soluble resin (A-1), the leveling property of the protective film composition is poor. Polyvinyl pyrrolidone-based water-soluble resin ( A-2 )

The K value of the polyvinyl pyrrolidone-based water-soluble resin (A-2) is in the range of 5 to 70, preferably 10 to 65, and more preferably 15 to 65.

Specific examples of polyvinyl pyrrolidone-based water-soluble resins (A-2) include the following commercially available products: PITZCOL K-30 (K value = 26 to 35, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), PVP K-12 (K value = 10 to 14, manufactured by Nippon Catalyst Co., Ltd.), PVP K-15 (K value = 13 to 19, manufactured by Nippon Catalyst Co., Ltd.), and PVP K-60 (K value = 50 to 62, manufactured by Nippon Catalyst Co., Ltd.). The polyvinyl pyrrolidone-based water-soluble resins (A-2) may be used alone or in combination of two or more.

Based on 100 parts by weight of the water-soluble resin (A), the amount of the polyvinyl pyrrolidone-based water-soluble resin (A-2) is 35 to 75 parts by weight, preferably 35 to 70 parts by weight, and more preferably 40 to 70 parts by weight. When the water-soluble resin (A) further includes the polyvinyl pyrrolidone-based water-soluble resin (A-2), the leveling property of the protective film composition can be further improved. Other water-soluble resins ( A-3 )

In addition to the polyvinyl pyrrolidone-based water-soluble resin (A-1) and the polyvinyl pyrrolidone-based water-soluble resin (A-2), the water-soluble resin (A) may further include other water-soluble resins (A-3) without affecting the effects of the present invention.

Other water-soluble resins (A-3) are used as the base of the protective film. There are no restrictions as long as they are materials that can form a film by coating and drying in a solvent such as water. Examples thereof include polyvinyl alcohol, polyethylene glycol having 5 or more ethyleneoxy repeating units, polyethylene oxide, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, polyacrylic acid, polyvinyl alcohol-polyacrylic acid block copolymer, polyvinyl alcohol-polyacrylate block copolymer, and polyglycerol. Other water-soluble resins (A-3) may be used alone or in combination of two or more.

The protective film formed on the wafer surface in the present invention is removed by water washing after laser processing. As other water-soluble resins (A-3), if the water washability of the protective film is taken into consideration, it is preferable to use a resin having only ether linkages or hydroxyl groups as polar groups, such as polyvinyl alcohol or polyethylene glycol. This is because water-soluble resins having polar groups such as carboxyl groups or tertiary amines will be tightly bonded to the wafer surface (chip surface) and may still remain on the wafer surface after washing with water. On the other hand, the adhesion of resins having only ether linkages or hydroxyl groups is relatively weak, so it can be effectively prevented from remaining after washing with water. From the viewpoint of water washability, the other water-soluble resin (A-3) preferably has a lower degree of polymerization or molecular weight. For example, polyvinyl alcohol preferably has a degree of polymerization of about 300. However, water-soluble resins having a high degree of polymerization or a high molecular weight have low water washability. However, in this case, the water washability can be prevented from decreasing when used in combination with the plasticizer described below.

Based on 100 parts by weight of the water-soluble resin (A), the amount of the other water-soluble resin (A-3) is 0 to 80 parts by weight, preferably 0 to 50 parts by weight, and more preferably 0 to 30 parts by weight. Laser light absorber ( B )

As the laser light absorber (B), water-soluble dyes, water-soluble pigments, and water-soluble ultraviolet light absorbers can be used. These absorbers are all water-soluble, and are advantageously uniformly present in the protective film. In addition, they show good affinity to the wafer surface, and can form a protective film that is highly adhered to the wafer surface. In addition, they have the advantage that their solutions have high storage stability, and during storage, there are no disadvantages such as phase separation or sedimentation, and satisfactory coating properties can be ensured. If a non-water-soluble laser light absorber such as a pigment is used, the laser absorption power of the protective film will change, or the storage stability or coating properties will be poor, making it difficult to form a protective film with uniform thickness.

As the water-soluble dye, there can be selected: azo dyes (monoazo and polyazo dyes, metal complex salt azo dyes, pyrazolone azo dyes, stilbene azo dyes, thiazole azo dyes), anthraquinone dyes (anthraquinone derivatives, anthrone derivatives), indigoid dyes (indigo derivatives, thioindigo derivatives), phenol cyanine dyes, carbon cation dyes (diphenylmethane dyes, triphenylmethane dyes, dibenzopyran dyes, acridine dyes), quinone imine dyes (oxazine dyes, oxazine dyes, thiazine dyes), methine dyes (cyanine dyes, azo methine dyes), quinoline dyes, nitroso dyes, benzoquinone dyes and naphthoquinone dyes, naphthamide imide dyes, perinone dyes and other dyes.

As water-soluble pigments, from the perspective of environmental load, it is better to use them as pigments for food additives, such as: Edible Red No. 2, Edible Red No. 40, Edible Red No. 102, Edible Red No. 104, Edible Red No. 105, Edible Red No. 106, Edible Yellow NY, Edible Yellow No. 4 Lemon Yellow, Edible Yellow No. 5, Edible Yellow No. 5 Sunset Yellow FCF, Edible Orange AM, Edible Vermilion No. 1, Edible Vermilion No. 4, Edible Vermilion No. 101, Edible Blue No. 1, Edible Blue No. 2, Edible Green No. 3, Edible Melon Color B, and Edible Egg Color No. 3.

As water-soluble ultraviolet light absorbers, there can be listed, for example, 4,4'-dicarboxybenzophenone, benzophenone-4-carboxylic acid, 2-carboxynaphthoquinone, 1,2-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid and 2,7-naphthalene dicarboxylic acid and their sodium salts, potassium salts, ammonium salts and quaternary ammonium salts, 2,6-anthraquinone disulfonic acid sodium salt, 2,7-anthraquinone disulfonic acid sodium salt and ferulic acid, among which ferulic acid is preferred.

The amount of laser light absorber (B) used is an amount that can ensure the desired laser light absorption. For example, when using laser light processing with a wavelength of 355 nm, the amount of laser light absorber (B) used is preferably such that the g absorption coefficient k of the protective film (i.e., the solid of the protective film composition) is in the range of 3×10 ^-3 to 2.5×10 ^-1 abs‧L/g (abs: absorbance). If the g absorption coefficient k is lower than the above range, the laser light absorption of the protective film is so low that the thermal decomposition of the protective film due to laser light irradiation is much lower than that of the silicon substrate. As a result, there is a tendency for the film to peel off due to the vapor pressure of the thermal decomposition product, and slag will be formed around the edge of the chip. If the g absorption coefficient k is higher than the above range, the protective film will be easily thermally decomposed due to reflection from the substrate when irradiated with laser light. Therefore, the processing width of the laser becomes larger than the laser spot diameter, which is not suitable for cutting along streets with fine line widths.

Furthermore, if a laser light absorber (B) having a maximum absorption wavelength range in the range of the laser light wavelength is selected, it is possible to ensure that the g absorption coefficient k is within the aforementioned range by using a small amount. If a laser light absorber that does not meet this condition is selected, a large amount must be used to ensure that the g absorption coefficient k is within the aforementioned range. However, if the amount of the laser light absorber (B) used is too large, when the protective film composition containing the laser light absorber (B) is applied and dried to form a protective film, phase separation may occur between the laser light absorber (B) and the water-soluble resin (A). If the amount of the laser light absorber (B) used is too small, the distribution of the laser light absorber (B) in the protective film may be uneven.

Based on 100 parts by weight of the water-soluble resin (A), the amount of the laser light absorber (B) is 1 to 30 parts by weight, preferably 3 to 30 parts by weight, and more preferably 5 to 25 parts by weight. Solvent ( C )

The solvent (C) is not particularly limited as long as it is a solvent that can dissolve the water-soluble resin (A) and the laser light absorber (B). Examples of the solvent (C) include water, alcohols, esters, alkanediol, alkanediol monoalkyl ethers, and alkanediol monoalkyl ether acetates. Among them, water and alkanediol monoalkyl ethers are preferred. As the alkanediol monoalkyl ether, propylene glycol monomethyl ether (PGME) is preferred. For the working environment, the best solvent is water or a mixed solvent containing water.

Based on 100 parts by weight of the water-soluble resin (A), the amount of the solvent (C) is 500 parts by weight to 3000 parts by weight, preferably 800 parts by weight to 3000 parts by weight, and more preferably 1000 parts by weight to 2500 parts by weight. Additive ( D )

In the present invention, in addition to the water-soluble resin (A) and the laser light absorber (B), an additive (D) may be added to the protective film composition without affecting the effect of the present invention. Specific examples thereof include plasticizers and surfactants.

Plasticizers are used to improve the water washability of the protective film after laser processing. It is especially preferred to use plasticizers when using a water-soluble resin (A) with a high molecular weight. Another advantage of using a plasticizer is that it can inhibit the carbonization of the water-soluble resin caused by irradiation with laser light. Plasticizers are preferably water-soluble, low molecular weight compounds. Examples include ethylene glycol, triethylene glycol, tetraethylene glycol, ethanolamine and glycerol. These compounds can be used alone or in combination of two or more. The amount of plasticizer used is such that after the protective film composition is applied and dried, there is no phase separation between the plasticizer and the water-soluble resin (A). For example, based on 100 parts by weight of the water-soluble resin (A), the recommended amount is 75 parts by weight or less, preferably 20 to 75 parts by weight.

Surfactants are used to improve the coating properties and further improve the storage stability of the protective film composition. Any surfactant of non-ionic, cationic, anionic or amphoteric type can be used as long as it is water-soluble.

Examples of nonionic surfactants include surfactants based on nonylphenol, high carbon alcohols, polyhydroxy alcohols, polyoxyalkylene glycols, polyoxyethyl alkyl esters, polyoxyethyl alkyl ethers, polyoxyethyl alkylphenol ethers, and polyoxyethyl sorbitan alkyl esters. Examples of cationic surfactants include quaternary ammonium salts and amine salts. Examples of anionic surfactants include alkylbenzene sulfonic acid and its salts, alkyl sulfate salts, methyl taurine salts, and ether sulfonates. Examples of amphoteric surfactants include surfactants based on imidazoline betaine, amidopropyl betaine, and aminodipropionate. Surfactants can be used alone or in combination of two or more. The amount of the surfactant may be tens or hundreds of ppm based on the protective film composition.

In the protective film composition for laser cutting of the present invention, the solid content in the protective film composition must be set according to the type, degree of polymerization or molecular weight of the water-soluble resin used so that the protective film composition has appropriate coating properties. If the solid content is too high, coating will become difficult, which may easily lead to uneven thickness or bubble entry. If the solid content is too low, the protective film composition may drip when applied to the wafer surface, and it is difficult to adjust the film thickness (protective film thickness) after drying. Therefore, although the solid content in the protective film composition varies depending on the water-soluble resin (A) used, it is preferably set at about 3% by weight to 30% by weight. The amount of water-soluble resin (A) in the solid component is usually 5% by weight or more. This is preferable from the viewpoint of providing the protective film with appropriate strength and preventing residue from being deposited on the chip surface. > Method for manufacturing protective film composition >

The manufacturing method of the protective film composition of the present invention is not particularly limited, and can be prepared by mixing the above-mentioned components. The mixing of the components is usually carried out in the range of 0°C to 100°C. In addition, after mixing the components, it is preferably filtered by a filter, for example. The filtering can be carried out in multiple stages and can be repeated multiple times. In addition, the filtered protective film composition can also be re-filtered.

As the filter, any material that has been used in filtering applications before can be used without particular limitation. For example, filters made of fluororesins such as polytetrafluoroethylene (PTFE), polyamide resins such as nylon-6 and nylon-6,6, and polyolefin resins such as polyethylene and polypropylene (PP) (including high-density and ultra-high molecular weight) can be cited. Among the above raw materials, polypropylene (including high-density polypropylene) and nylon are preferred.

The pore size of the filter is preferably about 0.5 μm to 100 μm. By setting the pore size within the above range, clogging of the filter can be suppressed, and fine foreign matter such as impurities and aggregates contained in the composition can be reliably removed.

When using filters, different filters can be combined. In this case, the filtering in the first filter can be performed only once or twice or more. When different filters are combined and filtering is performed twice or more, the pore diameter after the second filtration is preferably the same as or smaller than the pore diameter of the first filtration. In addition, first filters with different pore diameters can also be combined within the above range. The pore diameter here can refer to the nominal value of the filter manufacturer. Commercially available filters include filters provided by NIHON PALL Co., Ltd., Advantec Toyo Co., Ltd., Nihon Entegris Co., Ltd. (formerly Nihon Mykrolis Co., Ltd.), and KITZ MICRO FILTER Co., Ltd. > Manufacturing method of semiconductor device, laser cutting method >

Next, a method for manufacturing a semiconductor device and a laser cutting method of the present invention are described.

The manufacturing method and laser cutting method of the semiconductor device of the present invention include: applying the protective film composition of the present invention to a substrate to form a protective layer (step 1); irradiating the substrate with laser light through the protective layer to perform laser cutting (step 2); rinsing the substrate after laser cutting to remove the protective layer from the substrate (step 3).

The laser cutting method of the present invention can be applied to the manufacture of semiconductor devices, which is described below. However, the laser cutting method of the present invention can be applied to all uses of cutting substrates in addition to the manufacture of semiconductor devices. The steps of the manufacturing method of semiconductor devices and the laser cutting method of the present invention are described below.

<<Step 1>> In step 1, the protective film composition of the present invention is applied to a substrate to form a protective layer. The substrate can be any substrate known in semiconductor devices without limitation, such as a silicon substrate, a compound semiconductor substrate, etc. Specific examples of compound semiconductor substrates include SiC substrates, SiGe substrates, ZnS substrates, ZnSe substrates, GaAs substrates, InP substrates, GaN substrates, etc.

A mechanical structure or circuit can be formed on the surface of the substrate. Examples of substrates on which mechanical structures or circuits are formed include: micro-electromechanical systems (MEMS), power components, image sensors, micro-sensors, light-emitting diodes (LEDs), optical components, interposers, embedded components, micro-components, etc.

The thickness of the substrate is preferably 10 μm or more, more preferably 20 μm or more, and particularly preferably 50 μm or more. The upper limit is preferably 500 μm or less, more preferably 200 μm or less, and particularly preferably 100 μm or less. The present invention can form a good cutting shape in laser cutting even for a substrate made of a brittle material such as a low dielectric constant material.

Examples of methods for applying the protective film composition include casting, doctor blade coating, wire rod coating, spray coating, dipping coating, droplet coating, air knife coating, curtain coating, inkjet coating, spin coating, Langmuir-Blodgett (LB) method, etc. In the present invention, casting, spin coating, and inkjet are particularly preferred.

The thickness of the protective film is not particularly limited and can be appropriately adjusted according to the purpose and use. For example, it is preferably 0.5 μm to 20 μm, and more preferably 1 μm to 5 μm.

<<Step 2>> Then, laser light is irradiated to the substrate through the protective layer, and laser cutting is performed along the line of the substrate to be cut. The protective film contains a laser light absorber and thus has high laser light absorption energy. If the laser light is irradiated to the substrate through the protective film, the expansion of the laser light in the film can be suppressed, and the protective film is thermally decomposed and fractured at the laser light irradiation site at the same time as or before the thermal decomposition of the substrate.

In addition, since the substrate is covered with a protective film in the portion not irradiated with laser light, the surface of the substrate can be protected from the influence of residues such as thermal decomposition products of the substrate and the adhesion of residues can be prevented.

Furthermore, the protective film is unlikely to produce performance degradation of the laser light absorber due to laser irradiation, and can efficiently suppress the expansion of the laser light in the protective film. Therefore, when laser cutting is performed on a thick substrate, the expansion of the laser light can also be efficiently suppressed by the protective film, resulting in a good cutting shape.

The laser light source used for laser cutting is not particularly limited, and examples thereof include: Yttrium Aluminum Garnet (YAG) laser, Yttrium Lithium Fluoride (YLF) laser, Yttrium Vanadium Oxide (YVO4) laser, excimer laser, semiconductor laser, and the like.

The wavelength of the laser light is preferably 200 nm to 600 nm, more preferably 300 nm to 500 nm. The spot diameter of the laser light is not particularly limited, for example, preferably 0.1 μm to 50 μm, more preferably 1 μm to 20 μm.

Furthermore, the spot diameter (D) of the laser light can be calculated according to the following formula (3) when the pulsed laser light is focused by the objective lens of the condenser for irradiation. D = 4 × λ × f / (π × W) ··· (3) In formula (3), D is the spot diameter of the laser light (μm) λ is the wavelength of the pulsed laser light (μm) W is the diameter of the pulsed laser light incident on the condenser objective lens (mm) f is the focal distance of the condenser objective lens (mm)

<<Step 3>> Next, the substrate after laser cutting is washed with water to remove the protective layer from the substrate. Since the protective film contains a water-soluble resin, it can be easily removed from the substrate by washing with water. In addition, as the protective film is removed, the residues attached to the protective film are also washed away.

The water washing conditions of the protective film are not particularly limited. They can be appropriately adjusted according to the thickness of the protective film, etc. In this way, a semiconductor device such as a separated semiconductor chip can be obtained. > Example >

The present invention will be further described with respect to the following embodiments, but it should be understood that these embodiments are only for illustration and should not be construed as limitations on the implementation of the present invention.

The following describes Examples 1 to 13 and Comparative Examples 1 to 6 of the protective film composition:

Example 1 100 parts by weight of PVP K-85 (equivalent to polyvinyl pyrrolidone-based water-soluble resin (A-1), referred to as A-1-1) and 10 parts by weight of food red No. 102 (equivalent to laser light absorber (B), referred to as B-1) were added to a mixed solvent of 100 parts by weight of propylene glycol monomethyl ether (C-1) and 400 parts by weight of water (C-2). The mixture was added to a mixer equipped with a stirrer at room temperature and stirred at 500 rpm for 1 hour to obtain the protective film composition of Example 1.

Examples 2 to 13 The protective film compositions of Examples 2 to 13 are prepared by the same steps as Example 1, and the difference lies in that the types and amounts of the components of the water-soluble resin (A), the laser light absorber (B), and the solvent (C) are changed (as shown in Tables 1 and 2).

Comparative Examples 1 to 6 The protective film compositions of Comparative Examples 1 to 6 were prepared by the same steps as Example 1, and the difference was that the types and amounts of the components of the water-soluble resin (A), the laser light absorber (B), and the solvent (C) were changed (as shown in Table 2).

The compounds corresponding to the numbers in Table 1 and Table 2 are as follows: Abbreviation Element A-1-1 PVP K-85 (K value = 83~88, manufactured by Japan Catalyst Co., Ltd.) A-1-2 PITZCOL K-90 (K value = 88~100, manufactured by Daiichi Industry Pharmaceutical Co., Ltd.) A-1-3 PVP K-120 (K value = 114~130, manufactured by Japan Catalyst Co., Ltd.) A-2-1 PVP K-12 (K value = 10~14, manufactured by Japan Catalyst Co., Ltd.) A-2-2 PVP K-15 (K value = 13~19, manufactured by Japan Catalyst Co., Ltd.) A-2-3 PITZCOL K-30 (K value = 26~35, manufactured by Daiichi Industrial Pharmaceutical Co., Ltd.) A-2-4 PVP K-60 (K value = 50~62, manufactured by Japan Catalyst Co., Ltd.) A-3-1 Polyvinyl alcohol PXP-05 (manufactured by Nippon Vinyl Acetate Monomer and Polyvinyl Alcohol Co., Ltd.) A-3-2 Polyvinyl alcohol PXP-18 (produced by Nippon Vinyl Acetate Monomer and Polyvinyl Alcohol Co., Ltd.) B-1 Edible Red No. 102 B-2 2,6-Naphthalenedicarboxylic Acid B-3 Anthraquinone-2,6-disulfonic Acid Disodium Salt B-4 Ferulic acid C-1 Propylene glycol monomethyl ether (PGME) C-2 water

[Table 1] Ingredients (parts by weight) Embodiment 1 2 3 4 5 6 7 8 9 10 Polyvinyl pyrrolidone-based water-soluble resin (A-1) A-1-1 100 - - 50 25 - - 35 - - A-1-2 - 100 - 50 - 40 - - 45 - A-1-3 - - 100 - - - 65 - - 60 Polyvinyl pyrrolidone-based water-soluble resin (A-2) A-2-1 - - - - - - - 65 - - A-2-2 - - - - - - - - 55 - A-2-3 - - - - - - - - - 30 A-2-4 - - - - - - - - - - Other water-soluble resins (A-3) A-3-1 - - - - 75 60 - - - - A-3-2 - - - - - - 35 - - - Laser light absorber (B) B-1 10 - - - 1 - - - 25 - B-2 - 3 - - - 15 - - - 8 B-3 - - 5 - - - 28 - - - B-4 - - - 20 - - - 10 - - Solvent (C) C-1 100 150 350 100 100 150 350 100 150 350 C-2 400 750 1650 400 400 750 1650 400 750 1650 Leveling evaluation ○ ○ ○ ○ ○ ○ ○ ◎ ◎ ◎

[Table 2] Ingredients (parts by weight) Embodiment Comparison Example 11 12 13 1 2 3 4 5 6 Polyvinyl pyrrolidone-based water-soluble resin (A-1) A-1-1 - 30 - - - - - - - A-1-2 50 - 25 - - - - - - A-1-3 - - 30 - - - - - - Polyvinyl pyrrolidone-based water-soluble resin (A-2) A-2-1 - 35 45 100 - - 100 - - A-2-2 - - - - 50 - - 50 - A-2-3 - 35 - - - - - - - A-2-4 50 - - - - - - - - Other water-soluble resins (A-3) A-3-1 - - - - - 100 - - 100 A-3-2 - - - - 50 - - 50 - Laser light absorber (B) B-1 10 - - - - - 5 - - B-2 - - 30 - - - - 10 - B-3 20 - - - - - - - 20 B-4 - 15 - - - - - - - Solvent (C) C-1 500 500 500 150 200 300 150 200 300 C-2 2500 2000 2000 750 800 1200 750 800 1200 Leveling evaluation ◎ ◎ ◎ X X X X X X > Evaluation Method >

Leveling 100 mL of the protective film composition from the embodiment and the comparative example was taken and placed in a 500 mL beaker. The protective film composition was then stirred at 500 rpm for 4 hours, and the surface tension of the protective film composition was measured using a surface tension meter (CBVP-2, Concord). The leveling criteria based on the evaluation of surface tension are as follows: ◎: Surface tension > 35 mN/m ○: 35 mN/m ≦ Surface tension > 40 mN/m △: 40 mN/m ≦ Surface tension > 50 mN/m ╳: 50 mN/m ≦ Surface tension

As shown in Tables 1 and 2, the protective film composition of the present invention (Example 1-13) has good leveling properties because it uses a polyvinyl pyrrolidone-based water-soluble resin (A-1) with a K value of 75 to 150 and a laser light absorber (B).

In contrast, when the polyvinyl pyrrolidone-based water-soluble resin (A-1) having a K value of 75 to 150 (Comparative Example 1-6) is not used in the protective film composition, the resulting protective film composition has a problem of poor leveling.

In addition, when the protective film composition further contains a polyvinyl pyrrolidone-based water-soluble resin (A-2) having a K value of 5 to 70 (Examples 8-13), the leveling property of the protective film composition can be further improved.

In summary, the protective film composition of the present invention uses a polyvinyl pyrrolidone-based water-soluble resin (A-1) with a K value of 75 to 150 and a laser light absorber (B), and thus can improve the technical problem of poor leveling in the prior art.

Although the present invention has been disclosed as above by the embodiments, they are not intended to limit the present invention. Any person with ordinary knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be defined by the scope of the attached patent application.

Claims (9)

A protective film composition comprises: a water-soluble resin (A); a laser light absorber (B); and a solvent (C), wherein the water-soluble resin (A) comprises a polyvinyl pyrrolidone-based water-soluble resin (A-1) and a polyvinyl pyrrolidone-based water-soluble resin (A-2), the K value of the polyvinyl pyrrolidone-based water-soluble resin (A-1) is 75 to 150, and the polyvinyl pyrrolidone-based water-soluble resin (A-2) is 1 to 200 μm. -2) has a K value of 5 to 70, based on the usage of the water-soluble resin (A) being 100 parts by weight, the usage of the polyvinyl pyrrolidone-based water-soluble resin (A-1) being 25 to 65 parts by weight, the usage of the polyvinyl pyrrolidone-based water-soluble resin (A-2) being 35 to 75 parts by weight, and the laser light absorber (B) being a water-soluble pigment or a water-soluble ultraviolet light absorber. As described in item 1 of the patent application, the K value of the polyvinyl pyrrolidone-based water-soluble resin (A-1) is 80 to 140. As described in item 1 of the patent application, the K value of the polyvinyl pyrrolidone-based water-soluble resin (A-1) is 80 to 130. As described in item 1 of the patent application, the K value of the polyvinyl pyrrolidone-based water-soluble resin (A-2) is 10 to 65. As described in item 1 of the patent application, the K value of the polyvinyl pyrrolidone-based water-soluble resin (A-2) is 15 to 65. The protective film composition as described in item 1 of the patent application scope, wherein the amount of the water-soluble resin (A) used is 100 parts by weight, the amount of the laser light absorber (B) used is 1 part by weight to 30 parts by weight, and the amount of the solvent (C) used is 500 parts by weight to 3000 parts by weight. A protective film composition as described in any one of items 1 to 6 of the patent application scope, which is used for laser cutting. A method for manufacturing a semiconductor device, comprising: applying a protective film composition as described in any one of items 1 to 6 of the patent application scope to a substrate to form a protective layer; irradiating the substrate with laser light through the protective layer to perform laser cutting; and washing the substrate after laser cutting to remove the protective layer from the substrate. A laser cutting method, comprising: applying a protective film composition as described in any one of items 1 to 6 of the patent application scope to a substrate to form a protective layer; irradiating the substrate with laser light through the protective layer to perform laser cutting; and washing the substrate after laser cutting to remove the protective layer from the substrate.