ADHESIVE SHEET FOR TEMPORARY ATTACHMENT AND METHOD FOR PRODUCING SEMICONDUCTOR DEVICE USING THE SAME

Abstract

The present disclosure relates to an adhesive sheet for temporary attachment which is excellent in heat resistance and can realize sufficient adhesive strength even when being subjected to a high temperature process during the semiconductor production process, and can exhibit a sufficient reduction in adhesive strength due to photocuring in a peeling step, and a method for producing a semiconductor device using the same.

Claims

1. An adhesive sheet for temporary attachment, comprising: a substrate film having an elongation in the machine direction (MD) of 200% or more when stretched at a rate of 300 mm/min at 23 C.; and an adhesive layer containing a binder resin having a photoreactive functional group, a photoinitiator having activity at a wavelength of at least 300 nm, and a multifunctional crosslinking agent, wherein a ratio R of an adhesive strength A2 measured after irradiating a heat-treated adhesive layer with light relative to an initial adhesive strength A1 measured after heat treating the adhesive layer at a temperature of 90 C. to 150 C. is 30% or less.

2. The adhesive sheet for temporary attachment according to claim 1, wherein the ratio R of the adhesive strength A2 measured after irradiating a heat-treated adhesive layer with light relative to the initial adhesive strength A1 measured after heat treating the adhesive layer at a temperature of 90 C. to 150 C. is defined as the following General Formula 1:
R(%)=A2*100/A1[General Formula 1] wherein, in the General Formula 1, A1 is the initial adhesive strength of the adhesive layer measured after heat treatment at 100 C. for 3 hours, and A2 is the adhesive strength of the adhesive layer measured after irradiating the heat-treated adhesive layer with ultraviolet light in the composite wavelength region of 200 nm to 500 nm at a dose of 100 mJ/cm.sup.2 to 1000 mJ/cm.sup.2.

3. The adhesive sheet for temporary attachment according to claim 1, wherein the substrate film has a transmittance of at least 50% at a wavelength of at least 300 nm.

4. The adhesive sheet for temporary attachment according to claim 1, wherein the substrate film includes at least one polymer compound selected from a polyolefin, a polyester, a polycarbonate, a polyvinyl chloride, a polytetrafluoroethylene, a polybutene, a polybutadiene, an ethylene-vinyl acetate copolymer, an ethylene-propylene copolymer, an ethylene-alkyl acrylate copolymer and a polybutylene terephthalate.

5. The adhesive sheet for temporary attachment according to claim 1, wherein the binder resin includes a first (meth)acrylate-based repeating unit containing a benzoylphenyl group and a second (meth)acrylate-based repeating unit containing at least one functional group selected from a hydroxyl group, a carboxyl group and a nitrogen-containing functional group, and wherein 20 to 95 mol % of the second (meth)acrylate-based repeating unit includes a photopolymerizable (meth)acrylate-based side chain.

6. The adhesive sheet for temporary attachment according to claim 1, wherein the photoinitiator is at least one material compound selected from bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 1-hydroxy-cyclohexyl-phenyl-ketone 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-methyl-1-4-(methylthio)phenyl]-2-morpholinopropane-1-one, oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethylester, oxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethylester, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, and thioxanthone.

7. The adhesive sheet for temporary attachment according to claim 1, wherein the adhesive sheet is for a protective film for a semiconductor process, a carrier film, or a film for a pickup process.

8. The adhesive sheet for temporary attachment according to claim 1, further comprising a release film on one surface of the adhesive layer on which the substrate film is not formed.

9. The adhesive sheet for temporary attachment according to claim 1, wherein the adhesive layer is formed on one surface of the substrate film, and the adhesive sheet further comprises a release film formed on one surface of the adhesive layer on which the substrate film is not formed.

10. The adhesive sheet for temporary attachment according to claim 1, wherein the adhesive layer is formed of two layers, the adhesive layers are formed on respective surfaces of the substrate film, and the adhesive sheet further comprises a release film on the surface of the adhesive layer on which the substrate film is not formed.

11. A method for producing a semiconductor device comprising the steps of: attaching an adhesive layer of the adhesive sheet for temporary attachment according claim 1 to a predetermined portion of a semiconductor device; subjecting the semiconductor device to which the adhesive sheet is attached to a predetermined process; irradiating the substrate film of the adhesive sheet for temporary attachment with ultraviolet light after the predetermined process; and detaching the adhesive sheet for temporary attachment from the semiconductor device.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0125] FIGS. 1 and 2 schematically show a cross-sectional structure of an adhesive sheet 10 for temporary attachment according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0126] Preferred examples are given to facilitate understanding of the invention.

[0127] However, these examples are presented for illustrative purposes only, and the scope of the invention is not limited thereto.

Preparation Examples: Preparation of Composition for Forming Adhesive Layer

Preparation Example 1

[0128] A monomer mixture consisting of 75 g of 2-ethylhexyl acrylate (2-EHA), 5 g of 4-benzoylphenylmethacrylate, and 20 g of hydroxyethyl acrylate (HEA) was put into a reactor equipped with a cooling system so as to achieve reflux of a nitrogen gas and ease of temperature control.

[0129] Subsequently, 400 pm of n-DDM (n-dodecyl mercaptan) as a chain transfer agent (CTA) and 100 g of ethyl acetate (EAc) as a solvent based on 100 g of the monomer mixture were added thereto, and sufficiently mixed with each other at 30 C. for 30 minutes or more while injecting nitrogen in order to remove oxygen in the reactor.

[0130] Then, the temperature was increased to and maintained at 62 C., and V-60 (azobisisobutyronitrile) at 300 ppm as a reaction initiator was added thereto to thereby initiate the reaction, followed by polymerization for 6 hours to prepare a primary reaction material.

[0131] 24 g of 2-methacyloxyethyl isocyanate (MOI) (90 mol % based on HEA in the primary reaction material) and 0.24 g of a catalyst (DBTDL: dibutyltin dilaurate) were mixed in the primary reaction material, and reacted at 40 C. for 24 hours to introduce an ultraviolet curing group into the side chain of the polymer in the primary reaction material, thereby preparing a (meth)acrylate-based binder resin (a-1).

[0132] 4 g of a TDI-based isocyanate curing agent and 2 g of bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide as a photoinitiator were mixed with 100 g of the (meth)acrylate-based binder resin (a-1), thereby preparing a composition (A-1) for forming an adhesive layer.

Preparation Example 2

[0133] A monomer mixture consisting of 20 g of ethyl acrylate, 63 g of 2-ethylhexyl acrylate (2-EHA), 2 g of 4-benzoylphenyl acrylate, and 15 g of hydroxyethyl acrylate (HEA) was put into a reactor equipped with a cooling system so as to achieve reflux of a nitrogen gas and ease of temperature control.

[0134] Subsequently, 400 pm of n-DDM (n-dodecyl mercaptan) as a chain transfer agent (CTA) and 100 g of ethyl acetate (EAc) as a solvent based on 100 g of the monomer mixture were added thereto, and sufficiently mixed with each other at 30 C. for 30 minutes or more while injecting nitrogen in order to remove oxygen in the reactor.

[0135] Then, the temperature was increased to and maintained at 62 C., and V-60 (azobisisobutyronitrile) at 300 ppm as a reaction initiator was added thereto to thereby initiate the reaction, followed by polymerization for 6 hours to prepare a primary reaction material.

[0136] 15 g of 2-methacyloxyethyl isocyanate (MOI) (76 mol % based on HEA in the primary reaction material) and 0.15 g of a catalyst (DBTDL: dibutyltin dilaurate) were mixed in the primary reaction material, and reacted at 40 C. for 24 hours to introduce an ultraviolet curing group into the side chain of the polymer in the primary reaction material, thereby preparing a (meth)acrylate-based binder resin (a-2).

[0137] 5 g of a TDI-based isocyanate curing agent and 3 g of bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide as a photoinitiator were mixed with 100 g of the (meth)acrylate-based binder resin (a-2), thereby preparing a composition (A-2) for forming an adhesive layer.

Preparation Example 3

[0138] 4 g of a TDI-based isocyanate curing agent and 3 g of 2,2-dimethoxy-1,2-diphenylethane-1-one as a photoinitiator were mixed with 100 g of the (meth)acrylate-based binder resin (a-1) of Preparation Example 1, thereby preparing a composition (A-3) for forming an adhesive layer.

Comparative Preparation Example 1

[0139] A monomer mixture consisting of 80 g of 2-ethylhexyl acrylate (2-EHA), and 20 g of hydroxyethyl acrylate (HEA) was put into a reactor equipped with a cooling system so as to achieve reflux of a nitrogen gas and ease of temperature control.

[0140] Subsequently, 400 pm of n-DDM (n-dodecyl mercaptan) as a chain transfer agent (CTA) and 100 g of ethyl acetate (EAc) as a solvent based on 100 g of the monomer mixture were added thereto, and sufficiently mixed with each other at 30 C. for 30 minutes or more while injecting nitrogen in order to remove oxygen in the reactor.

[0141] Then, the temperature was increased to and maintained at 62 C., and V-60 (azobisisobutyronitrile) at 300 ppm as a reaction initiator was added thereto to thereby initiate the reaction, followed polymerization for 6 hours to prepare a primary reaction material.

[0142] 24 g of 2-methacyloxyethyl isocyanate (MOI) (90 mol % based on HEA in the primary reaction material) and 0.24 g of a catalyst (DBTDL: dibutyltin dilaurate) were mixed in the primary reaction material, and reacted at 40 C. for 24 hours to introduce an ultraviolet curing group into the side chain of the polymer in the primary reaction material, thereby preparing a (meth)acrylate-based binder resin (b-1).

[0143] 4 g of a TDI-based isocyanate curing agent and 2 g of bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide as a photoinitiator were mixed with 100 g of the (meth)acrylate-based binder resin (b-1), thereby preparing a composition (B-1) for forming an adhesive layer.

Comparative Preparation Example 2

[0144] 4 g of a TDI-based isocyanate curing agent was mixed with 100 g of the (meth)acrylate-based binder resin (a-1) of Preparation Example 1, thereby preparing a composition (B-2) for forming an adhesive layer.

EXAMPLES AND COMPARATIVE EXAMPLES

Example 1

[0145] The composition (A-1) for forming an adhesive layer of Preparation Example 1 was coated onto a release-treated polyethylene terephthalate film (38 m thick) and then dried at 110 C. for 3 minutes to form an adhesive layer having a thickness of about 30 m.

[0146] The formed adhesive layer was laminated onto a 100 m-thick substrate film, a polypropylene film, and then subjected to aging to obtain an adhesive sheet for temporary attachment.

Examples 2-3 and Comparative Examples 1-2

[0147] The adhesive sheet for temporary attachment was prepared in the same manner as in Example 1, except that the components and use amounts shown in the following Table 1 were applied.

[0148] The elongation (%) of the substrate film was the elongation in the MD (machine direction) when the specimen having a width of 5 mm and a length of 40 mm was stretched at a rate of 300 mm/min at 23 C.

TABLE-US-00001 TABLE 1 Substrate film Category (elongation (%)) Adhesive layer Example 1 Polypropylene (420) Preparation Example 1(A-1) Example 2 Polybutylene Preparation terephthalate (792) Example 2(A-2) Example 3 Polypropylene (420) Preparation Example 3(A-3) Comparative Polypropylene (420) Comparative Preparation Example 1 Example 1(B-1) Comparative Polypropylene (420) Comparative Preparation Example 2 Example 2(B-2) Comparative Polyethylene Preparation Example 3 naphthalate (126) Example 1(A-1)

Experiment 1: Evaluation of Adhesive Strength and Peel Strength

[0149] For the adhesive sheets for temporary attachment prepared according to the examples and comparative examples, the adhesive strength and the peel strength due to photocuring were evaluated by the following method, and the results are shown in Table 2 below.

[0150] The adhesive sheets for temporary attachment prepared in the examples and comparative examples were cut to a width of 25 mm, and then a sample adhered to a silicon wafer using a 2 kg roller was prepared.

[0151] Subsequently, a heat-treated sample was prepared, which was left on a hot plate at 100 C. for 3 hours so as to make contact with the substrate surface of the adhesive sheet for temporary attachment adhered to the silicon wafer.

[0152] (1) Evaluation of Adhesion Property

[0153] The adhesion strength (gf/25 mm) of the adhesive sheet was measured at a speed of 300 mm/min and an angle of 180 degrees using a Texture Analyzer manufactured by Stable Micro Systems.

[0154] (2) Evaluation of Peeling Property

[0155] The non-heat treated sample and the heat treated sample prepared as above were subjected to ultraviolet irradiation under the conditions of intensity of 300 mJ/cm.sup.2 (using a mercury lamp with a composite wavelength of 200 nm to 500 nm) on the substrate film side. The irradiated sample and the non-irradiated sample were tested for their properties, and the obtained results were evaluated.

[0156] In addition, the adhesive strength ratio (R) was measured by the following general formula through the above measured adhesive strength.

R(%)=A2*100/A1[General Formula 1]

[0157] in General Formula 1, A1 is the adhesive strength of the adhesive layer measured after heat treatment at 100 C. for 3 hours, and A2 is the adhesive strength of the adhesive layer measured after heat treatment followed by ultraviolet irradiation.

Experimental Example 2: Evaluation of Pick-Up Properties

[0158] After the release films of the adhesive sheets for temporary attachment produced according to the examples and comparative examples were peeled off, the adhesive layer surfaces were mounted at a temperature of 25 C. in a mirror wafer (8 inches, thickness of 80 m).

[0159] Next, a heat-treated sample was prepared, which was left on a hot plate of 100 C. for 3 hours so as to make contact with the substrate film surface of the temporary attaching adhesive sheet attached to the silicon wafer.

[0160] A dicing process was performed on the heat-treated sample under the following conditions so as to have a chip size of 10 mm10 mm.

[0161] Subsequently, the diced sample was irradiated by ultraviolet light having an intensity of 300 mJ/cm.sup.2 from the substrate surface to prepare samples for measuring pick-up properties.

[0162] The prepared samples were picked up under the following conditions by using SPA-400 (SHINKAWA) equipment, and the success rate thereof was measured as shown in Table 2 below.

[0163] Dicing Conditions

[0164] Device: DFD-650 (DISCO)

[0165] Blade type: 27HEBB (DISCO)

[0166] Cutting blade height (cut depth): 80 um

[0167] Dicing speed: 50 mm/s

[0168] Rotation speed of blade: 40,000 rpm

[0169] Pick-Up Conditions

[0170] Device: SPA-400 (SHINKAWA)

[0171] Expanding height: 3 mm

[0172] Number of Needles: 10

[0173] Needle plunge height: 0.2 mm

[0174] Needle plunge speed: 10 mm/s

TABLE-US-00002 TABLE 2 Adhesive strength(gf/25 mm) evaluation (after heat treatment) Pick-up Before light After light success Category R (%) irradiation irradiation rate (%) Example 1 6.63 208 13.8 100 Example 2 7.92 331 26.2 100 Example 3 5.10 298 15.2 100 Comparative 69.44 180 125 5 Example 1 Comparative 40.16 254 102 13 Example 2 Comparative 15.81 203 32.1 0 Example 3

[0175] It is confirmed from Table 2 above that the adhesive sheets for temporary attachment prepared according to the present disclosure had an adhesive strength ratio (R) of less than 30% even after the heat treatment, so that the adhesive sheet had a large reduction in adhesion strength and could be removed without residual adhesive.

[0176] In contrast, in Comparative Examples 1 and 2, the adhesive strength ratio R after the heat process was 30% or more and the adhesive strength was high, so that the occurrence of the adhesive residue and the success rate of the pickup were insufficient.

[0177] It was confirmed that in Comparative Example 3, not only did it have a low rate of change in adhesive strength, but also the stretching property of the substrate film was insufficient and thus the pickup process was impossible.

DESCRIPTION OF SIGNS

[0178] 10: adhesive sheet for temporary attachment

[0179] 100: substrate film

[0180] 200: adhesive layer

[0181] 300: release film