JP2010084034A - Adhesive film for protecting silicon oxide film surface for forming epitaxial film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive film for protecting silicon oxide film surface for epitaxial film formation which has an appropriate stickiness and adhesiveness to a silicon oxide film surface, which can be easily peeled when peeling and removing, and the impurity metastatic property derived from an adhesive film to the silicon oxide film surface after peeling is small. <P>SOLUTION: The adhesive film sequentially forms an adhesive layer and a release layer on a base material, in which the adhesive layer comprises an acrylic based resin, an isocyanate based cross-linking agent and a nonionic surfactant, the peeling strength after 0.5 hours sticking on the silicon oxide film surface is 0.05-0.20 N/20 mm measured under the peeling test conditions at 300 mm/min peeling velocity, 150 mm peeling distances, 20 mm test-body width and at 180°, and the peeling strength after 24 hours sticking on is -30 to +30% compared to the peeling strength after 0.5 hours, and a ratio with respect to the whole elements of carbon in the silicon oxide film surface after peeling the adhesive film sticking on 24 hours is 8-18%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention enables easy peeling even when affixed to a silicon oxide film surface on which an epitaxial film is formed for a long time, and transfers impurities from the adhesive film to the silicon oxide film surface after peeling. The present invention relates to a pressure-sensitive adhesive film for protecting a silicon oxide film for forming an epitaxial film having a slight property.

  After a circuit pattern is formed on the front surface of a silicon wafer, the back surface is polished for thinning. In this polishing process, the thinned wafer can be damaged, or the pattern surface can be contaminated by polishing debris or the like. Therefore, a protective adhesive film is used to prevent these problems. Such a protective adhesive film is applied to the surface of the wafer before polishing, and is peeled and removed after processing. It is desirable that when the wafer is peeled and removed, it exhibits an easy peelability that does not damage the thinned wafer. Therefore, various attempts have been made to impart such characteristics to the adhesive film.

  So far, the adhesive film for wafer protection that has been reported has been provided with a radiation curable adhesive layer and an adhesive layer having a storage elastic modulus in a specific range on one surface of a base film (patent document) 1) and those having an expansion layer containing a thermally decomposable hydrazide compound between the base film layer and the adhesive layer (see Patent Document 2).

However, although these adhesive films for protecting the wafer surface have both excellent adhesion to the wafer surface and easy releasability, complicated treatments such as radiation irradiation and heating are required at the time of peeling.
JP 2002-53819 A JP 2005-332900 A

  By the way, the adhesive film for protecting the wafer surface can be used for forming an epitaxial film in addition to the purpose of preventing damage and contamination during the polishing process as described above. In the epitaxial film forming step, an oxide film is formed on the surface of the silicon wafer. At this time, an adhesive film having a size slightly smaller than the shape of the wafer is attached to the oxide film. And after removing the oxide film of the site | part to which the adhesive film is not stuck by chemical | medical solution process, an adhesive film is peeled and an oxide film is made to grow. By doing so, an oxide film can be grown without protruding the shape of the wafer.

  However, the oxide film is a sticking target in which the pressure-sensitive adhesive film is inferior in adhesiveness and adhesiveness compared to a normal wafer surface, and the sticking of the pressure-sensitive adhesive film tends to progress with time and is difficult to peel off. . Therefore, development of an adhesive film suitable for protecting the oxide film surface formed on the surface of the silicon wafer has been desired.

  The present invention has been made in view of the above-mentioned problems, and its object is to have appropriate adhesiveness and adhesiveness to the silicon oxide film surface while it is affixed. When removing from the film surface, it can be easily removed without complicated processing, and the formation of an epitaxial film in which the transfer of impurities from the adhesive film to the silicon oxide film surface after peeling is slight It is providing the adhesive film for silicon oxide film surface protection for.

  The present inventor has intensively studied to create a pressure-sensitive adhesive film suitable for protecting the surface of a silicon wafer, and an acrylic resin is used as a main component of the pressure-sensitive adhesive layer, and an isocyanate cross-linking agent and a nonionic surface active agent are used for this. By adding an agent, an adhesive film suitable for protecting an oxide film surface (hereinafter referred to as a silicon oxide film surface) formed on a silicon wafer for growing an epitaxial film can be obtained. The headline and the present invention were completed. Specifically, the following are provided.

(1) In an adhesive film in which an adhesive layer and a release layer are sequentially formed on a substrate,
The pressure-sensitive adhesive layer contains an acrylic resin, an isocyanate-based crosslinking agent, and a nonionic surfactant, and was measured under 180 ° peel test conditions with a peel speed of 300 mm / min, a peel distance of 150 mm, and a specimen width of 20 mm. In addition, the peel strength after 0.5 hours has been applied to the silicon oxide film surface is 0.05 to 0.20 N / 20 mm, and the peel strength after 24 hours has been applied is 0.5 hours later The epitaxial film is characterized in that it has a peel strength of -30 to + 30% and a ratio of carbon to all elements on the silicon oxide film surface after peeling of the adhesive film stuck for 24 hours is 8 to 18%. Silicone oxide surface protective adhesive film for forming.

  (2) The nonionic surfactant is blended in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of the acrylic resin. An adhesive film for protecting the silicon oxide film surface.

  (3) The adhesive film for protecting a silicon oxide film surface for forming an epitaxial film according to (1) or (2), wherein the HLB of the nonionic surfactant is 10 to 16.

  (4) The acrylic film formation according to any one of (1) to (3), wherein the acrylic resin is a copolymer having butyl acrylate and 2-ethylhexyl acrylate as main constituent monomers. For protecting silicon oxide film surface.

  (5) The silicon oxide film surface protective adhesive film for epitaxial film formation according to any one of (1) to (4), wherein the wettability of the silicon oxide film surface is 60 dyn / cm or less .

  The pressure-sensitive adhesive film of the present invention uses an acrylic resin as a main component of the pressure-sensitive adhesive layer, and is blended with an isocyanate-based cross-linking agent and a nonionic surfactant. Adhesiveness and adhesion can be obtained. In addition, even when affixed for a long time, since the change in the peel strength between the silicon oxide film surface is small, it is easily peeled off without any special treatment when removing from the silicon oxide film surface. Furthermore, the impurity transfer property derived from the adhesive film to the silicon oxide film surface after peeling is slight. Therefore, it is suitable for protecting the silicon oxide film surface for forming an epitaxial film.

  Hereinafter, specific embodiments of the present invention will be described in detail.

  An adhesive film for protecting a silicon oxide film for forming an epitaxial film of the present invention (hereinafter referred to as an adhesive film) is an adhesive film in which an adhesive layer and a release layer are sequentially formed on a substrate. The pressure-sensitive adhesive layer contains an acrylic resin, an isocyanate-based crosslinking agent, and a nonionic surfactant, and is subjected to 180 ° peeling test conditions (“JIS”) with a peeling speed of 300 mm / min, a peeling distance of 150 mm, and a specimen width of 20 mm. Measured in accordance with “Z0237”), the peel strength after 0.5 hours passed from the silicon oxide film surface was 0.05 to 0.20 N / 20 mm, and the peel strength after 24 hours pasted. However, it is -30 to + 30% of the peel strength after 0.5 hours, and the percentage of carbon on the silicon oxide film surface after peeling of the adhesive film stuck for 24 hours with respect to all elements. The total content is 8 to 18%.

  As for the adhesive film 1 of this invention, the adhesive layer 12 and the peeling layer 13 are formed in order on the base material 11 (refer FIG. 1).

  If the base material 11 has required intensity | strength and a softness | flexibility, it will not specifically limit, Generally a synthetic resin film is used. As the material of the synthetic resin film, polyester resin, polypropylene resin, poly (4-methyl-pentene-1) resin, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, polyvinyl chloride resin, Vinyl chloride-vinyl acetate copolymer, polyvinylidene chloride resin, fluorine resin, polystyrene resin, poly (meth) acrylic resin, polyvinyl butyral resin, polyacrylonitrile resin, cellulose acetate resin, polycarbonate resin, Known resins such as polyamide resins, polyester resins, polyvinyl alcohol resins, polyphenylene sulfide resins, polyether ether ketone resins, para aramid resins, polyurethane resins and the like can be mentioned. In the present invention, among these, it is particularly preferable to use a polyester-based resin from the viewpoint of chemical resistance such as rigidity, extensibility, dimensional stability, flexibility, and stackability.

  Examples of the polyester resin include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, polyarylate, polytetramethylene terephthalate, and the like.

  Although the thickness of the base material 11 is not specifically limited, Preferably it is 12-188 micrometers, More preferably, it is 25-100 micrometers. If it is the said range, since the form of an adhesive film can be maintained, workability | operativity, such as sticking and peeling of an adhesive film, will become favorable.

  The pressure-sensitive adhesive layer 12 includes an acrylic resin, a nonionic surfactant, and an isocyanate-based crosslinking agent. As monomers constituting the acrylic resin, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, cyclohexyl acrylate, isooctyl acrylate, n-octyl acrylate, lauryl acrylate, stearyl Examples include acrylic acid alkyl esters having an alkyl group having 1 to 20 carbon atoms such as acrylate, and one or more of these may be used in combination. In the present invention, among these, butyl acrylate and 2-ethylhexyl acrylate are preferable from the viewpoints of adhesiveness and adhesion to the silicon oxide film surface at the time of sticking, and versatility, and butyl acrylate and 2-ethylhexyl acrylate. The combined use is more preferable.

  Isocyanate crosslinking agents include phenylene diisocyanate, diphenyl diisocyanate, triisocyanate toluene, triisocyanate benzene, diphenyl ether diisocyanate, naphthylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate and other aromatic polyisocyanates, hexamethylene diisocyanate, trimethylene diisocyanate. , Aliphatic polyisocyanates such as pentamethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, trimethylhexamethylene diisocyanate, alicyclic polyisocyanates such as cyclopentane diisocyanate, cyclohexane diisocyanate, trimethylcyclohexyl isocyanate, diisocyanate Sulfonates dimethylbenzene, it includes aromatic aliphatic polyisocyanates such as diisocyanates diethylbenzene, may be used in combination with one or more of these.

  The amount of the isocyanate-based crosslinking agent is preferably 1.0 to 5.0 parts by mass, more preferably 1.5 to 3.0 parts with respect to 100 parts by mass of the acrylic resin that is the main component of the pressure-sensitive adhesive layer 12. Part by mass. When using 2 or more types together, the compounding quantity as a whole is meant. If it is the said range, since appropriate bridge | crosslinking formation is made | formed, moderate adhesiveness and adhesiveness with respect to a silicon oxide film surface can be provided to an adhesive film.

  Nonionic surfactants include polyoxyethylene lauryl ether, polyoxyethylene isodecyl ether, polyoxyethylene isotridecyl ether, polyoxyalkylene isotridecyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether , Polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester, polyoxyalkylene branched decyl ether, and the like, and those having HLB of 10 to 16 are preferred, and those of 10 to 15 are more preferred. In addition, the value of HLB in the present invention is represented by the Griffin formula (this Griffin formula is HLB = (molecular weight of hydrophilic group portion / surfactant molecular weight) × (100/5) ( “Introduction to New Surfactant”, Sanyo Chemical Industries, Ltd., issued on November 1, 1985, page 128)).

  In the present invention, a nonionic surfactant having chemical resistance is used among the surfactant species because there is chemical treatment in the process of forming the epitaxial film. Of these, polyoxyalkylene branched decyl ether is preferred from the viewpoints of dilutability in organic solvents and low transfer of impurities to the silicon oxide film surface after peeling of the adhesive film. Here, “HLB” is obtained by weighted averaging of the HLB of the surfactant. When two or more kinds of surfactants are used in combination, the average HLB is meant. If it is the said range, since the physical property of the adhesive layer 12 surface shows hydrophobicity, progress of the wetting with respect to a silicon oxide film surface will become slow. Therefore, even when the surface of the pressure-sensitive adhesive layer 12 and the silicon oxide film surface are adhered for a long time, the change in the peel strength is small, so that the peel-off can be easily performed. Moreover, if it is the said range, it is liquid at normal temperature and shows the favorable solubility to an organic solvent.

  The compounding amount of the nonionic surfactant is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the acrylic resin that is the main component of the pressure-sensitive adhesive layer 12. It is. When using 2 or more types together, the compounding quantity as a whole is meant. If it is the said range, since the physical property of the adhesive layer 12 surface shows hydrophobicity, progress of the wetting with respect to a silicon oxide film surface will become slow. Therefore, even when the surface of the pressure-sensitive adhesive layer 12 and the silicon oxide film surface are adhered for a long time, the change in the peel strength is small, so that the peel-off can be easily performed.

  In addition, various additives such as a metal chelating agent, an antioxidant, a tackifier, and an ultraviolet absorber can be blended as necessary without departing from the object of the present invention.

  Although it does not specifically limit as a formation method of the adhesive layer 12, For example, the method by printing, coating, etc. is mentioned. Further, the thickness of the pressure-sensitive adhesive layer 12 can be appropriately selected within a range that does not impair the adhesiveness and adhesion to the silicon oxide film surface in consideration of the state and shape of the silicon oxide film surface. 60 μm, preferably 20 to 50 μm. If it is the said range, since the favorable adhesiveness with respect to a silicon oxide film surface is shown, the penetration | invasion of a chemical | medical solution can be prevented.

  The release layer 13 is made of a release member having peelability laminated on the pressure-sensitive adhesive layer 12, and has a function of protecting the surface of the pressure-sensitive adhesive layer 12. The release member is not particularly limited as long as it has necessary strength and flexibility, and a synthetic resin film subjected to silicone release treatment is generally used. As a material of the synthetic resin film, for example, polyester resins such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, polyarylate, polytetramethylene terephthalate are preferable. The thickness of the release layer 13 is not particularly limited, but is preferably 25 to 125 μm.

  In the pressure-sensitive adhesive film 1 of the present invention, a pressure-sensitive adhesive (hereinafter referred to as pressure-sensitive adhesive solution) dissolved in an organic solvent is applied to a substrate 11 and dried to form a pressure-sensitive adhesive layer 12 having a desired thickness. It can be manufactured by forming. It does not specifically limit as an organic solvent, For example, toluene, hexane, acetone, ethyl acetate etc. are mentioned. As a method of applying the adhesive solution to the substrate, conventionally known methods such as a roll coating method, a gravure coating method, a micro gravure coating method, a reverse coating method, a roll brush method, a spray coating method, an air knife coating method, impregnation Method, curtain coating method, die coating method, doctor blade method, comma coating method and the like. Although the drying conditions of the applied adhesive are not specifically limited, Usually, it dries for 30 seconds-3 minutes in the temperature range of 40-120 degreeC. Although the thickness of the adhesive film 1 of this invention can be suitably selected according to the objective, Usually, it is 47-373 micrometers.

  The pressure-sensitive adhesive film 1 of the present invention is applied to a silicon oxide film surface measured under 180 ° peel test conditions (in accordance with “JIS Z0237”) having a peel speed of 300 mm / min, a peel distance of 150 mm, and a specimen width of 20 mm. The peel strength after 5 hours is 0.05 to 0.20 N / 20 mm, and the peel strength after 24 hours is pasted is -30 to + 30% of the peel strength after 0.5 hours. And preferably -10 to + 10%. While the adhesive film 1 of the present invention is stuck, the adhesive film 1 has adhesiveness and adhesiveness to such an extent that the thinned silicon wafer can be prevented from being damaged and chemicals can be prevented from entering. And even when affixed for a long time, since the change in the peel strength between the silicon oxide film surface is small, it is easily peeled off without any special treatment when removing from the silicon oxide film surface. be able to.

  The pressure-sensitive adhesive film 1 of the present invention is characterized in that the ratio of carbon to all elements on the silicon oxide film surface after peeling of the pressure-sensitive adhesive film stuck for 24 hours is 8 to 18%, preferably 8 to 17%, more preferably 8 to 16%. In the pressure-sensitive adhesive film 1 of the present invention, the transfer property of carbon, which is an impurity derived from the pressure-sensitive adhesive film, to the silicon oxide film surface after peeling is slight.

  Moreover, as for the adhesive film 1 of this invention, in the adhesive layer, it is preferable that the contact angle of water after 302 second dropping of water is 40 to 90% immediately after dripping, and it is 50 to 90%. Further preferred. Since the pressure-sensitive adhesive film 1 of the present invention has moderate wettability with respect to the silicon oxide film surface, the thinned silicon wafer is prevented from being damaged or infiltrated with chemicals while it is applied. It has sufficient adhesiveness and adhesion. Generally, the adhesive strength of an adhesive film increases with the passage of time after being attached to an adherend. This is because the adhesive of the adhesive film and the adherend become wet. The pressure-sensitive adhesive film 1 of the present invention has a very gradual change in wettability and a small change in pressure-sensitive adhesive force, so that it can be easily peeled even when applied to the silicon oxide film surface for a long time. .

  Furthermore, the pressure-sensitive adhesive film 1 of the present invention preferably has a silicon oxide film surface whose wettability (according to JIS K6760) is 60 dyn / cm or less. The adhesive film 1 of the present invention can be easily peeled off without any special treatment even when it is applied to the wet silicon oxide film surface for a long time.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these Examples.

[Method of forming adhesive film]
<Example 1>
Using an applicator, a pressure-sensitive adhesive solution (acrylic pressure-sensitive adhesive) so that the release layer 13 (PET separator film, trade name “0010BD”, film thickness 50 μm, manufactured by Fujimori Kogyo Co., Ltd.) has a film thickness after drying of 40 μm. (Main composition: 2-ethylhexyl acrylate and butyl acrylate, trade name “Cybinol ATR340”, manufactured by Seiden Chemical Co., Ltd.), isocyanate-based crosslinking agent (trade name “K200”, manufactured by Seiden Chemical Co., Ltd.), 2.3 parts by mass, An ionic surfactant (trade name “XL-80”, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and an aluminum metal chelating agent (trade name “M2”, manufactured by Seiden Chemical Co., Ltd.) 0.23 parts by mass are diluted with a solvent. And dissolved in 60 parts by mass of toluene) to form an adhesive layer 12. Next, the diluted solvent in the pressure-sensitive adhesive layer 12 was volatilized in an oven (90 ° C., 1 minute), and the substrate 11 (PET film, trade name “S105”, film thickness 50 μm) was applied to the coated surface of the pressure-sensitive adhesive layer 12 after drying. , Manufactured by Toray Industries, Inc.) was laminated and subjected to an aging treatment at 40 ° C. for 3 days to form an adhesive film 1 as shown in FIG. The main component of the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive, and the blending amounts of the main component and the nonionic surfactant are as shown in Table 1.

<Example 2>
The same as Example 1 except that the compounding amount of the nonionic surfactant in the adhesive solution is 1 part by mass.

<Example 3>
The same as Example 1 except that the compounding amount of the nonionic surfactant in the adhesive solution is 2 parts by mass.

<Example 4>
The same as Example 1 except that the compounding amount of the nonionic surfactant in the adhesive solution is 5 parts by mass.

<Example 5>
The same as Example 1 except that the compounding amount of the nonionic surfactant in the adhesive solution is 10 parts by mass.

<Comparative Example 1>
The same as Example 1 except that the blending amount of the nonionic surfactant in the adhesive solution is 20 parts by mass.

<Comparative example 2>
The same as Example 1 except that the compounding amount of the nonionic surfactant in the adhesive solution is 30 parts by mass.

<Comparative Example 3>
The same as Example 1 except that the nonionic surfactant is not blended in the adhesive solution.

[Measurement of peel strength]
The adhesive film 1 was cut into a width of 20 mm to produce a test piece. A CVD oxide film is formed on the surface of the single crystal silicon wafer by the CZ method on the test piece in a CVD furnace under the conditions of target: 20 mm, atmosphere: helium gas base, monosilane, oxygen gas, temperature: 400 ° C., holding time: 15 seconds. Was laminated using a 2 kg roller and left at room temperature for 30 minutes to 24 hours. Then, using a tensile tester (RTF-1150-H), the peel strength at normal temperature and normal temperature was measured (speed: 300 mm / min, peel distance: 150 mm, peel angle: 180 °) (based on JIS Z0237) ). The results are shown in Table 1 and FIG.

  The adhesive film 1 (Examples 1 to 5) in which the compounding amount of the surfactant is 0.5 to 10 parts by mass with respect to 100 parts by mass of the acrylic resin as the main agent is 24 hours after adhesion to the silicon oxide film surface. However, no change in peel strength was observed. From this, it was found that by controlling the amount of the nonionic surfactant to be blended in the pressure-sensitive adhesive, it is possible to suppress the change in the pressure-sensitive adhesive force with the passage of time after sticking. The peel strength was also stable for the pressure-sensitive adhesive film 1 (Comparative Example 3) that did not contain a surfactant.

[Elemental analysis]
Next, the residue derived from the adhesive on the silicon oxide film surface after peeling of the adhesive film 1 was confirmed by elemental analysis. The measurement conditions are shown below. Table 2 shows the analysis results of the adhesive surface of the adhesive film 1 before adhering to the silicon oxide film surface, the silicon oxide film surface after the adhesive film 1 is peeled, and the silicon oxide film surface before adhering the adhesive film 1.
<Measurement conditions>
Measuring equipment: XPS (ESCALAB 220i-XL)
X-ray light source: Monochromatic X-ray X-ray output: 10 kV, 17.5 mA (175 W)
Lens: Magnetic lens Measurement area: 700 μmφ

  The pressure-sensitive adhesive film 1 (Comparative Example 3) containing no surfactant showed stability over time in the measurement of the peel strength, but it was derived from the pressure-sensitive adhesive on the silicon oxide film surface after the pressure-sensitive adhesive film 1 was peeled off. There was more carbon which is a residue than the adhesive film 1 (Examples 1-3) which mix | blended surfactant. From this, it was found that the contamination of the silicon oxide film surface is suppressed by adding the surfactant.

[Examination of surfactant]
Using an applicator, a pressure-sensitive adhesive solution (acrylic pressure-sensitive adhesive) so that the release layer 13 (PET separator film, trade name “0010BD”, film thickness 50 μm, manufactured by Fujimori Kogyo Co., Ltd.) has a film thickness after drying of 40 μm. (Main composition: 2-ethylhexyl acrylate and butyl acrylate, trade name “Cybinol ATR340”, manufactured by Seiden Chemical Co., Ltd.), isocyanate-based crosslinking agent (trade name “K200”, manufactured by Seiden Chemical Co., Ltd.), 2.3 parts by mass, An ionic surfactant and 0.23 parts by mass of an aluminum-based metal chelating agent (trade name “M2”, manufactured by Seiden Chemical Co., Ltd.) dissolved in 60 parts by mass of toluene as a diluent solvent) An adhesive layer 12 was formed. Next, the diluted solvent in the pressure-sensitive adhesive layer 12 was volatilized in an oven (90 ° C., 1 minute), and the substrate 11 (PET film, trade name “S105”, film thickness 50 μm) was applied to the coated surface of the pressure-sensitive adhesive layer 12 after drying. , Manufactured by Toray Industries, Inc.) was laminated and subjected to an aging treatment at 40 ° C. for 3 days to form an adhesive film 1 as shown in FIG. The main component of the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive. Table 3 shows the types of the nonionic surfactant and the blending amounts of the main agent and the nonionic surfactant.
Next, the adhesive film 1 formed by the above method was cut into a width of 20 mm to prepare a test piece. A CVD oxide film is formed on the surface of the single crystal silicon wafer by the CZ method on the test piece in a CVD furnace under the conditions of target: 20 mm, atmosphere: helium gas base, monosilane, oxygen gas, temperature: 400 ° C., holding time: 15 seconds. Was laminated using a 2 kg roller and left at room temperature for 30 minutes to 24 hours. Then, using a tensile tester (RTF-1150-H), the peel strength at normal temperature and normal temperature was measured (speed: 300 mm / min, peel distance: 150 mm, peel angle: 180 °) (based on JIS Z0237) ). The results are shown in Table 3.

  A change in peel strength with time was observed in the adhesive film in which the blending amount of both Neugen XL-40 of HLB 10.5 and Neugen XL-100 of HLB 14.7 was increased. From this, it was found that even when surfactants having different HLBs were blended, the change in adhesive strength with the lapse of time after sticking could be suppressed by controlling the blending amount.

[Measurement of contact angle]
Under an environment of 25 ° C. and a humidity of 50%, 2 dL of pure water was dropped from the height of 2 cm onto the surface of the pressure-sensitive adhesive film 1 (pressure-sensitive adhesive layer 12), and the contact angle was measured (based on JIS R3257). The time from dropping to measurement was 2 to 302 seconds. The results are shown in Table 4.

  When the compounding amount of the surfactant with respect to the acrylic resin as the main agent was large, the contact angle of water with the passage of time showed a large change. This result is considered to be because when the amount of the surfactant is large, the physical properties of the adhesive surface are more hydrophilic, and the progress of wetting with respect to the silicon oxide film surface becomes faster. That is, if the amount of the surfactant is large, the compatibility of the adhesive surface with the silicon oxide film surface increases, and it is considered that the peel strength increases with time. From this, it was found that the change in wetting with the passage of time after sticking can be controlled by adjusting the amount of the nonionic surfactant to be added to the adhesive.

It is sectional drawing which shows the adhesive film for silicon oxide film surface protection for epitaxial film formation of one Embodiment. It is a figure which shows the time-dependent change of peeling strength.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Silicon oxide film surface protection adhesive film for epitaxial film formation 11 Base material 12 Adhesive layer 13 Release layer

Claims (5)

In the adhesive film in which the adhesive layer and the release layer are sequentially formed on the substrate,
The pressure-sensitive adhesive layer contains an acrylic resin, an isocyanate-based crosslinking agent, and a nonionic surfactant,
A peel strength of 0.5 to 0.20 N / 0.5 hours after being applied to the silicon oxide film surface measured under 180 ° peel test conditions with a peel speed of 300 mm / min, a peel distance of 150 mm, and a specimen width of 20 mm. 20 mm, and the peel strength after 24 hours has been -30 to + 30% of the peel strength after 0.5 hours;
The adhesive film for protecting a silicon oxide film for the formation of an epitaxial film, characterized in that a ratio of carbon to all elements on the silicon oxide film surface after peeling of the adhesive film applied for 24 hours is 8 to 18% .   The silicon oxide film for epitaxial film formation according to claim 1, wherein the nonionic surfactant is blended in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of the acrylic resin. Adhesive film for surface protection.   The adhesive film for protecting a silicon oxide film surface for forming an epitaxial film according to claim 1 or 2, wherein the nonionic surfactant has an HLB of 10 to 16.   4. The silicon oxide film for epitaxial film formation according to claim 1, wherein the acrylic resin is a copolymer having butyl acrylate and 2-ethylhexyl acrylate as main constituent monomers. 5. Adhesive film for surface protection.   5. The adhesive film for protecting a silicon oxide film surface for forming an epitaxial film according to claim 1, wherein the wettability of the silicon oxide film surface is 60 dyn / cm or less.

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