Adhesive sheet for temporary fixation and method of manufacturing semiconductor device using the same

Abstract

An adhesive sheet for temporary fixation which may have excellent heat resistance to exhibit a sufficient adhesive force even though it undergoes a high temperature process during a process of manufacturing a semiconductor device and may also exhibit a sufficient reduction of the adhesive force by photocuring during the step of peeling off, and a method of manufacturing a semiconductor device using the same, are provided.

Claims

1. An adhesive sheet for temporary fixation, the adhesive sheet comprising: a polymer base film having a glass transition temperature (Tg) of at least 60° C.; and at least one adhesive layer including a binder resin having at least one photoreactive functional group; a photoinitiator having activity at a wavelength of 300 nm or more; and a tertiary amine compound, wherein a ratio (R) of an adhesive force (A2′) to an initial adhesive force (A1′) is 50% or less as defined by General Formula 1:
R(%)=A2′*100/A1′  [General Formula 1] wherein, in the General Formula 1, A1′ represents the adhesive force of the adhesive layer after heat treatment at 180° C. for 2 hours, and A2′ represents the adhesive force of the adhesive layer measured after light-irradiating the heat-treated adhesive layer with UV at a multi-wavelength of 200 nm to 500 nm at a light dose of 100 mJ/cm.sup.2 to 1000 mJ/cm.sup.2.

2. The adhesive sheet for temporary fixation of claim 1, wherein the polymer base film has transmittance of 50% or more at a wavelength of 300 nm or more.

3. The adhesive sheet for temporary fixation of claim 1, wherein the polymer base film includes one or more polymer compounds selected from the group consisting of polyimide, polyamideimide, polyetherether ketone, polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, and polyamide.

4. The adhesive sheet for temporary fixation of claim 1, wherein the binder resin includes a first (meth)acrylate repeating unit including a benzoylphenyl group; and a second (meth)acrylate repeating unit including one or more functional groups selected from the group consisting of a hydroxyl group, a carboxyl group, and a nitrogen-containing functional group, and 20 to 95 mol % of the second (meth)acrylate repeating unit including a photopolymerizable (meth)acrylate-based side chain.

5. The adhesive sheet for temporary fixation of claim 1, wherein the photoinitiator includes one or more selected from the group consisting of thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan-1-one, a mixture of oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethylether and oxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethylester, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

6. The adhesive sheet for temporary fixation of claim 1, wherein the tertiary amine compound includes one or more selected from the group consisting of ethyl-p-dimethyl aminobenzoate, methyl-p-dimethyl aminobenzoate, 2-ethylhexyl-p-dimethyl aminobenzoate, octyl-p-dimethyl aminobenzoate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, and N,N-dihydroxyethyl-p-toluidine.

7. The adhesive sheet for temporary fixation of claim 1, wherein a weight ratio of the photoinitiator and the tertiary amine compound is 1:1 to 20.

8. The adhesive sheet for temporary fixation of claim 1, wherein the adhesive sheet provides a function of a protective film or a carrier film of a semiconductor process.

9. The adhesive sheet for temporary fixation of claim 1, further comprising a release film on the adhesive layer.

10. The adhesive sheet for temporary fixation of claim 9, further comprising an additional release film, wherein the adhesive layer is composed of two layers, and the base film is positioned between the two layers and each release film is on each of the two layers opposite side to the base film.

11. A method of manufacturing a semiconductor device, the method comprising the steps of: attaching the adhesive layer of the adhesive sheet for temporary fixation of claim 1 onto a predetermined portion of the semiconductor device; performing a predetermined process of the semiconductor device on which the adhesive sheet is attached; irradiating UV rays onto the base film of the adhesive sheet for temporary fixation after performing the predetermined process; and detaching the adhesive sheet for temporary fixation from the semiconductor device.

12. The method of claim 11, wherein the predetermined process of the semiconductor device is performed at a temperature of 60° C. to 300° C.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIGS. 1 and 2 are schematic illustrations of a cross-sectional structure of an adhesive sheet for temporary fixation 10 according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(2) Hereinafter, preferred examples will be provided for better understanding of the present invention. However, the following examples are for illustrative purposes only, and the invention is not intended to be limited by these examples.

Preparation Example: Preparation of Composition for Forming Adhesive Layer

Preparation Example 1

(3) A monomer mixture consisting of 75 g of 2-ethylhexyl acrylate (2-EHA), 5 g of 4-benzoylphenyl methacrylate, and 20 g of hydroxyethyl acrylate (HEA) was introduced into a reactor equipped with a cooling system for reflux under nitrogen gas and easy control of the temperature. Subsequently, 400 pm of n-DDM 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 at 30° C. for 30 minutes or more while injecting nitrogen to remove oxygen in the reactor. Then, the temperature was increased and maintained at 62° C., 300 ppm of V-60 (azobisisobutyronitrile) as a reaction initiator was introduced to initiate the reaction, and then polymerization was allowed for 6 hours to prepare a primary reaction product.

(4) The primary reaction product was blended with 24 g (90 mol % with respect to HEA in the primary reaction product) of 2-methacryloyl oxyethyl isocyanate (MOI) and 0.24 g of a catalyst (DBTDL: dibutyl tin dilaurate), and reacted at 40° C. for 24 hours to introduce a UV curable group to the polymer side chain in the primary reaction product, thereby preparing a (meth)acrylate binder resin (a-1).

(5) 100 g of the (meth)acrylate binder resin (a-1) was mixed with 4 g of a TDI-based isocyanate curing agent, 3 g of isopropylthioxanthone as a photoinitiator, and 7 g of ethyl-p-dimethyl amino benzoate as an amine compound to prepare a composition for forming an adhesive layer (A-1).

Preparation Example 2

(6) 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 introduced into a reactor equipped with a cooling system for reflux under nitrogen gas and easy control of the temperature. 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 at 30° C. for 30 minutes or more while injecting nitrogen to remove oxygen in the reactor. Then, the temperature was increased and maintained at 62° C., 300 ppm of V-60 (azobisisobutyronitrile) as a reaction initiator was introduced to initiate the reaction, and then polymerization was allowed for 6 hours to prepare a primary reaction product.

(7) The primary reaction product was blended with 15 g (76 mol % with respect to HEA in the primary reaction product) of 2-methacryloyl oxyethyl isocyanate (MOI) and 0.15 g of a catalyst (DBTDL: dibutyl tin dilaurate), and reacted at 40° C. for 24 hours to introduce a UV curable group to the polymer side chain in the primary reaction product, thereby preparing a (meth)acrylate binder resin (a-2).

(8) 100 g of the (meth)acrylate binder resin (a-2) was mixed with 8 g of a TDI-based isocyanate curing agent, 3 g of isopropylthioxanthone as a photoinitiator, and 10 g of ethyl-p-dimethyl amino benzoate as an amine compound to prepare a composition for forming an adhesive layer (A-2).

Preparation Example 3

(9) 100 g of the (meth)acrylate binder resin (a-1) of Preparation Example 1 was mixed with 4 g of a TDI-based isocyanate curing agent, 3 g of bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide as a photoinitiator, and 7 g of ethyl-p-dimethyl amino benzoate as an amine compound to prepare a composition for forming an adhesive layer (A-3).

Preparation Example 4

(10) 100 g of the (meth)acrylate binder resin (a-1) of Preparation Example 1 was mixed with 2 g of a TDI-based isocyanate curing agent, 2 g of isopropylthioxanthone as a photoinitiator, and 5 g of 2-ethylhexyl-p-dimethyl amino benzoate as an amine compound to prepare a composition for forming an adhesive layer (A-4).

Comparative Preparation Example 1

(11) A monomer mixture consisting of 80 g of 2-ethylhexyl acrylate (2-EHA) and 20 g of hydroxyethyl acrylate (HEA) was introduced into a reactor equipped with a cooling system for reflux under nitrogen gas and easy control of the temperature. Subsequently, 400 pm of n-DDM 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 at 30° C. for 30 minutes or more while injecting nitrogen to remove oxygen in the reactor. Then, the temperature was increased and maintained at 62° C., 300 ppm of V-60 (azobisisobutyronitrile) as a reaction initiator was introduced to initiate the reaction, and then polymerization was allowed for 6 hours to prepare a primary reaction product.

(12) The primary reaction product was blended with 24 g (90 mol % with respect to HEA in the primary reaction product) of 2-methacryloyl oxyethyl isocyanate (MOI) and 0.24 g of a catalyst (DBTDL: dibutyl tin dilaurate), and reacted at 40° C. for 24 hours to introduce a UV curable group to the polymer side chain in the primary reaction product, thereby preparing a (meth)acrylate binder resin (b-1).

(13) 100 g of the (meth)acrylate binder resin (b-1) was mixed with 4 g of a TDI-based isocyanate curing agent, 3 g of isopropylthioxanthone as a photoinitiator, and 7 g of ethyl-p-dimethyl amino benzoate as an amine compound to prepare a composition for forming an adhesive layer (B-1).

Comparative Preparation Example 2

(14) 100 g of the (meth)acrylate binder resin (a-1) of Preparation Example 1 was mixed with 4 g of a TDI-based isocyanate curing agent to prepare a composition for forming an adhesive layer (B-2).

Comparative Preparation Example 3

(15) 100 g of the (meth)acrylate binder resin (a-1) of Preparation Example 1 was mixed with 2 g of a TDI-based isocyanate curing agent and 2 g of isopropylthioxanthone as a photoinitiator to prepare a composition for forming an adhesive layer (B-3).

Examples and Comparative Examples

Example 1

(16) The composition for forming an adhesive layer (A-1) of Preparation Example 1 was applied onto a polyethylene terephthalate film (thickness of 38 μm) which had been release-treated, and dried at 110° C. for 3 minutes to form an adhesive layer having a thickness of about 30 μm. The formed adhesive layer was laminated on a polyethylene naphthalate base film having a thickness of 100 μm, and then aged to obtain an adhesive sheet for temporary fixation.

Examples 2 to 4 and Comparative Examples 1 to 4

(17) Each adhesive sheet for temporary fixation was prepared in the same manner as in Example 1, except that components and amounts of the following Table 1 were applied.

(18) TABLE-US-00001 TABLE 1 Base film Adhesive layer Example 1 Polyethylene naphthalate, Tg: 153° C. Preparation Example 1 (A-1) Example 2 Polyamideimide, Tg: 308° C. Preparation Example 2 (A-2) Example 3 Polyethylene naphthalate, Tg: 153° C. Preparation Example 3 (A-3) Example 4 Polyethylene terephthalate, Tg: 92° C. Preparation Example 4 (A-4) Comparative Polyethylene naphthalate, Tg: 153° C. Comparative Preparation Example 1 Example 1 (B-1) Comparative Polyethylene naphthalate, Tg: 153° C. Comparative Preparation Example 2 Example 2 (B-2) Comparative Polyamideimide, Tg: 308° C. Comparative Preparation Example 3 Example 3 (B-3) Comparative Polypropylene, Tg: 10° C. Preparation Example 1 (A-1) Example 4

Experimental Example: Evaluations of Adhesive Force and Peelability

(19) The adhesive sheets for temporary fixation prepared according to the examples and comparative examples were evaluated for adhesive force and peelability according to photocuring by the following methods, and the results are shown in Table 2 below.

(20) Each of the adhesive sheets for temporary fixation prepared according to the examples and comparative examples was cut to have a width of 25 mm, and then attached to a silicon wafer using a 2 kg roller to prepare a sample A (before heat treatment).

(21) Next, the adhesive sheet for temporary fixation attached to the silicon wafer was left in an oven at 180° C. for 2 hours to prepare a heat-treated sample B (after heat treatment).

(22) The base films of the non-heat-treated sample A and the heat-treated sample B were or not irradiated with UV (using a mercury lamp having a mixed wavelength of 200 nm to 500 nm) at a light dose of 1000 mJ/cm.sup.2 to prepare respective samples, which were then evaluated for adhesive force.

(23) The adhesive force (gf/25 mm) was measured using a Texture Analyzer of Stable Micro Systems at a speed of 300 mm/min and an angle of 180 degrees, and the results are shown in Table 2 below.

(24) Further, the measured adhesive force was used to calculate an adhesive force ratio (R) by the following general formula, and the results are also shown in Table 2 below.
R(%)=A2′*100/A1′  [General Formula 1]

(25) In General Formula 1, A1′ represents the adhesive force of the adhesive layer which was measured after heat treatment at 180° C. for 2 hours, and A2′ represents the adhesive force of the adhesive layer measured after UV irradiation following the heat treatment.

(26) TABLE-US-00002 TABLE 2 Evaluation of adhesive force (gf/25 mm) of sample B after heat treatment Before light After light R (%) irradiation irradiation Example 1 2.55 785 20 Example 2 11.29 620 70 Example 3 12.32 812 100 Example 4 5.14 720 37 Comparative 97.89 380 372 Example 1 Comparative 99.57 703 700 Example 2 Comparative 64.58 542 350 Example 3 Comparative Not Not Not Example 4 measurable measurable measurable

(27) As confirmed in the data of the sample B after heat treatment in Table 2, the adhesive sheets for temporary fixation prepared according to the present invention showed an adhesive force ratio of less than 50% even after the high heat temperature process, indicating that the adhesive force was greatly reduced and the adhesive sheet was removable without adhesive residues. In contrast, Comparative Example 1 to Comparative Example 3 showed an adhesive force ratio of more than 50% after the high heat temperature process, and thus generated adhesive residues due to the high adhesive force. Comparative Example 4 showed a severe change in appearance such as wrinkles and delamination after the heat treatment due to lack of heat resistance of the base film, and thus its adhesive strength was not measurable.

REFERENCE NUMERALS

(28) 10: Adhesive sheet for temporary fixation 100: Base film 200: Adhesive layer 200(a): surface of the adhesive layer 200 210: first adhesive layer 220: second adhesive layer 220(a): surface of the second adhesive layer 220 300: Release film 310: first release film 320: second release film