JP2010163594A - Curable resin composition, curable resin film and plating method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable resin composition which can form a protective film that has excellent adhesiveness in plating and then is able to be conveniently released, and to provide a curable resin film. <P>SOLUTION: The curable resin composition comprises: (A) an urethane resin, (B) a photopolymerizable compound having one or more ethylenically unsaturated groups in the molecule, and (C) a photopolymerization initiator. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a curable resin composition, a curable resin film, and a plating method using the same.

  As various electronic components become more sophisticated, smaller, lighter, and highly integrated, the number of semiconductor elements mounted on a single substrate is increasing, and the density of semiconductor elements themselves is increasing. The semiconductor element is generally manufactured by cutting a 6 to 12 inch wafer (for example, a silicon wafer) having an electrode (hereinafter referred to as a surface electrode) formed on one side. In recent years, for the purpose of forming a through electrode, a semiconductor element in which an electrode such as gold, silver, or nickel (hereinafter referred to as a back electrode) is formed on the surface opposite to the surface on which the surface electrode is formed has been manufactured. Yes. In the manufacturing process of the semiconductor element on which the back electrode is formed, a step of performing plating treatment such as gold plating to form bumps on the front electrode is included, but the back electrode not subjected to plating treatment uses a protective film. It is necessary to protect it from being plated. It is desired that such a protective film has excellent adhesiveness during the plating process and can be easily peeled off after the plating process. However, when a general thermosetting adhesive is used as a protective film, although it is excellent in adhesiveness, it is difficult to peel off after curing.

  On the other hand, as a peelable adhesive, for example, Patent Document 1 discloses a heat-peelable pressure-sensitive adhesive sheet whose adhesiveness is reduced by heating.

Japanese Patent No. 3766304

  However, the heat-peelable pressure-sensitive adhesive sheet described in Patent Document 1 is used for temporarily fixing a component and can be repeatedly fixed and peeled, but the adhesiveness during heating is not sufficient, It is difficult to use in protective film applications such as silicon wafers that require high adhesion.

  The present invention has been made in view of the above circumstances, and has a superior adhesiveness during plating treatment, and a curable resin composition capable of forming a protective film that can be easily peeled off after plating treatment. And it aims at providing a curable resin film. Another object of the present invention is to provide a plating method using the curable resin composition.

  As a result of intensive studies to achieve the above object, the present inventors have made a urethane resin, a photopolymerizable compound having one or more ethylenically unsaturated groups in the molecule, and a curable resin containing a photopolymerization initiator. The composition exhibits sufficiently high adhesiveness to a substrate (adherent) such as a wafer, and when irradiated with actinic rays such as ultraviolet rays, the adhesiveness decreases easily due to curing of the curable resin composition. It has been found that it has both excellent adhesiveness and peelability that it can be peeled, and the present invention has been completed.

  That is, the present invention comprises (A) a urethane resin, (B) a photopolymerizable compound having one or more ethylenically unsaturated groups in the molecule, and (C) a photopolymerization initiator. A resin composition is provided.

  According to such a resin composition, when it has the above-described configuration, it exhibits excellent adhesion to a substrate (adhered body) such as a wafer, and when it is irradiated with actinic rays such as ultraviolet rays after adhesion, photocuring proceeds. Therefore, the adhesiveness is lowered, so that it can be easily peeled off from the substrate.

  In the curable resin composition of the present invention, the urethane resin (A) has a polybutadiene skeleton and / or a polyisoprene skeleton from the viewpoint of achieving both adhesiveness before irradiation with actinic rays and releasability after irradiation with actinic rays. It is preferable. In addition, the urethane resin having a polycarbonate skeleton can achieve both adhesiveness before irradiation with actinic rays and releasability after irradiation with actinic rays. A urethane resin having a polybutadiene skeleton and / or a polyisoprene skeleton is more preferable from the viewpoint of further improving the adhesiveness before irradiation with actinic rays. From the viewpoint of further improving the solubility in organic solvents, the peelability after irradiation with actinic rays, the chemical resistance and the water resistance while maintaining high adhesion before irradiation with actinic rays, the polybutadiene skeleton and / or polyisoprene skeleton In addition, it is particularly preferable to further have a polycarbonate skeleton.

  Furthermore, in the curable resin composition of the present invention, the photopolymerizable compound (B) having one or more ethylenically unsaturated groups in the molecule has three or more ethylenically unsaturated groups in the molecule. It is preferable to contain a compound. Thereby, the peelability after actinic ray irradiation can be improved more. Furthermore, by containing a urethane compound having a polycarbonate skeleton as a photopolymerizable compound having one or more ethylenically unsaturated groups in the molecule (B), the adhesiveness before irradiation with actinic rays can be further improved. In addition, chemical resistance and water resistance can be further improved.

  This invention also provides a curable resin film provided with a support film and the resin composition layer which consists of a curable resin composition of this invention formed on this support film. By forming the curable resin composition into a film, handling becomes easy, and it has excellent adhesiveness during the plating treatment, and can be easily peeled off by irradiation with actinic rays after the plating treatment.

  The present invention further includes a protective layer forming step of forming a protective layer comprising the curable resin composition of the present invention on one surface of the adherend, and a plating film on the surface opposite to the protective layer forming surface of the adherend. There is provided a plating method comprising: a plating process for forming a film; and a peeling process for irradiating the protective layer with an actinic ray to cause photocuring after the plating process and peeling the protective layer after photocuring from the adherend.

  According to the present invention, it is possible to provide a curable resin composition and a curable resin film that have excellent adhesiveness during plating treatment and enable formation of a protective film that can be easily peeled after plating treatment. Can do. Moreover, according to this invention, the plating method using the said curable resin composition can be provided.

(A)-(d) is a series of process figures which show typically an example of the plating method of this invention.

  In this specification, “(meth) acrylate” means “acrylate” and “methacrylate” corresponding thereto. Similarly, “(meth) acryl” means “acryl” and “methacryl” corresponding thereto, and “(meth) acryloyl” means “acryloyl” and corresponding “methacryloyl”.

  The curable resin composition of the present invention comprises (A) a urethane resin (hereinafter sometimes referred to as “component (A)”) and (B) a photopolymerizable compound having one or more ethylenically unsaturated groups in the molecule. A compound (hereinafter referred to as “component (B)” in some cases) and (C) a photopolymerization initiator (hereinafter referred to as “component (C)” in some cases). Hereinafter, each component will be described in detail.

<(A) component: urethane resin>
(A) The urethane resin can be obtained, for example, by reacting a diol compound with a compound having an isocyanate group. As the diol compound, it is preferable to use a diol compound having a double bond in the molecule, such as polybutadiene diol or polyisoprene diol. A urethane resin prepared by using polybutadienediol or polyisoprenediol has sufficiently high adhesiveness to an adherend (wafer or the like) before irradiation with actinic rays, and will be described later when irradiated with actinic rays (B ) The crosslink density with the component is improved and the adhesiveness can be lowered.

  Polybutadiene diol and polyisoprene diol include compounds having “1,4-repeat unit” or “1,2-repeat unit”.

Here, in the polybutadiene, “1,4-repeating unit” is a repeating unit represented by the following chemical formula (1t) or (1c), and “1,2-repeating unit” is the following chemical formula. It is a repeating unit represented by (1d).

［式（１）中、ｎ１は１〜６０の整数を示す。］ Examples of the polybutadiene diol mainly having 1,4-repeating units include Poly bd R-45HT and Poly bd R-15HT (trade name, manufactured by Idemitsu Kosan Co., Ltd.). Examples of the polybutadiene diol mainly having 1,2-repeating units include compounds represented by the following general formula (1). Specifically, G-1000, G-2000, G-3000 (Nippon Soda Co., Ltd.) Product name). Moreover, as polyisoprene diol which has a 1, 2- repeating unit mainly, Poly IP (made by Idemitsu Kosan Co., Ltd., brand name) is mentioned, for example.

[In Formula (1), n1 shows the integer of 1-60. ]

  In particular, considering the solubility of the produced (A) urethane resin in an organic solvent, a diol compound having a branched skeleton is preferable. As such a diol compound, a polybutadiene diol or a poly diol mainly having 1,2-repeating units is preferable. Isoprene diol is preferred.

  In addition, while maintaining high adhesiveness before irradiation with actinic rays, it is possible to further improve the solubility of the produced (A) urethane resin in an organic solvent, peelability after irradiation with actinic rays, chemical resistance and water resistance. From the viewpoint, it is preferable that the component (A) further has a polycarbonate skeleton. Such a urethane resin can be obtained by reacting polybutadiene diol and / or polyisoprene diol and polycarbonate diol with a compound having an isocyanate group.

［式（２）中、Ｒは炭素数１〜１８のアルキレン基を示し、ｍは１〜３０の整数を示す。］ As polycarbonate diol, the compound represented by following General formula (2) is mentioned, for example.

[In Formula (2), R shows a C1-C18 alkylene group, m shows the integer of 1-30. ]

  Examples of the polycarbonate diol represented by the general formula (2) include α, ω-poly (hexamethylene carbonate) diol and α, ω-poly (3-methyl-pentamethylene carbonate) diol, which are commercially available. Examples include PLACEL CD-205, 205PL, 205HL, 210, 210PL, 210HL, 220, 220PL, 220HL (trade name) manufactured by Daicel Chemical Industries, and PCDL T-5651, T-5651, T manufactured by Asahi Kasei Chemicals Corporation. -6001, T-6002 (trade name), UM-CARB90 (1/1) (trade name) manufactured by Ube Industries, Ltd., and the like. These can be used individually by 1 type or in combination of 2 or more types.

  When polycarbonate diol is used, the content thereof is 0.1 to 10 mol with respect to 1 mol of polybutadiene diol and / or polyisoprenediol from the viewpoint of adhesiveness before irradiation with actinic light and releasability after irradiation with actinic light. It is preferable that it is 0.5-5 mol, and it is especially preferable that it is 1-4 mol.

  In the present invention, a diol compound other than polybutadiene diol, polyisoprene diol and polycarbonate diol may be used in combination. Examples of such diol compounds include polyether diols, polyester diols, polycaprolactone diols, silicone diols, and dihydroxy compounds having a carboxyl group.

［式（３）中、Ｒ^１は、炭素数１〜５のアルキル基を示す。］ Examples of the dihydroxy compound having a carboxyl group include a compound represented by the following general formula (3).

[In Formula (3), R < ¹ > shows a C1-C5 alkyl group. ]

  Specific examples of the compound represented by the general formula (3) include dimethylolpropionic acid and dimethylolbutanoic acid.

  Since the urethane resin obtained by using the compound represented by the general formula (3) has a carboxyl group in the side chain, by modifying a part or all of the carboxyl group, ethylenic unsaturation having photocurability Groups can be introduced. As a result, it can function as a photocurable component when irradiated with actinic rays such as ultraviolet rays, and reduces the adhesiveness of a protective film (hereinafter sometimes referred to as a protective layer) by irradiation with actinic rays. The peelability can be further improved. The said ethylenically unsaturated group can be introduce | transduced by making 2-hydroxyethyl (meth) acrylate etc. react, for example. In addition, the urethane resin having a carboxyl group prepared by using the compound represented by the general formula (3) reacts with a curing agent such as an epoxy compound by heating, and thus functions as a thermosetting resin. The peelability of the protective layer can be further improved by curing.

(A) As a compound which has an isocyanate group used when synthesize | combining a component, the diisocyanate represented by following General formula (4) is mentioned, for example.
OCN-X-NCO (4)
[In formula (4), X represents a divalent organic group. ]

  Examples of the divalent organic group represented by X in the general formula (4) include, for example, an alkylene group having 1 to 20 carbon atoms, an unsubstituted group, or a lower alkyl group having 1 to 5 carbon atoms such as a methyl group. And arylene groups such as a phenylene group and a naphthylene group. The number of carbon atoms of the alkylene group is more preferably 1-18. The divalent organic group represented by X has an aromatic ring such as a phenylene group, a xylylene group, a naphthylene group, a diphenylmethane-4,4′-diyl group, a diphenylsulfone-4,4′-diyl group. Groups are preferred. A hydrogenated diphenylmethane-4,4'-diyl group is also preferred.

  Examples of the diisocyanates represented by the general formula (4) include diphenylmethane-2,4′-diisocyanate; 3,2′-, 3,3′-, 4,2′-, 4,3 ′. -, 5,2'-, 5,3'-, 6,2'- or 6,3'-dimethyldiphenylmethane-2,4'-diisocyanate; 3,2'-, 3,3'-, 4,2 '-, 4,3'-, 5,2'-, 5,3'-, 6,2'- or 6,3'-diethyldiphenylmethane-2,4'-diisocyanate; 3,2'-, 3, 3'-, 4,2'-, 4,3'-, 5,2'-, 5,3'-, 6,2'- or 6,3'-dimethoxydiphenylmethane-2,4'-diisocyanate; diphenylmethane -4,4'-diisocyanate; diphenylmethane-3,3'-diisocyanate; dipheny Diphenylmethane diisocyanate compounds such as methane-3,4′-diisocyanate and their hydrogenated products; diphenyl ether-4,4′-diisocyanate; benzophenone-4,4′-diisocyanate; diphenylsulfone-4,4′-diisocyanate; 2,4-diisocyanate; tolylene-2,6-diisocyanate; m-xylylene diisocyanate; p-xylylene diisocyanate; 1,5-naphthalene diisocyanate; 4,4 '-[2,2bis (4-phenoxyphenyl) propane ] Diisocyanate is mentioned. Like these diisocyanates, it is preferable to use an aromatic polyisocyanate in which X in the formula (4) is a group having an aromatic ring. These can be used alone or in combination of two or more.

  In addition, as the diisocyanates represented by the general formula (4), within the scope of the object of the present invention, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane. Aliphatic or alicyclic isocyanates such as diisocyanate, transcyclohexane-1,4-diisocyanate, hydrogenated m-xylylene diisocyanate, and lysine diisocyanate can be used. In addition, as a compound which has an isocyanate group, you may use trifunctional or more polyisocyanate with the diisocyanate represented by General formula (4).

  The diisocyanates represented by the general formula (4) may be stabilized with a blocking agent necessary for avoiding changes over time. Examples of the blocking agent include hydroxy acrylate, alcohol typified by methanol, phenol, oxime and the like, but there is no particular limitation.

  In the present invention, the reaction between the diol compound in the method for producing the urethane resin used as the component (A), the diisocyanate represented by the general formula (4), and a compound for introducing various skeletons, It can be carried out by heat condensation in the presence of an organic solvent, preferably a non-nitrogen-containing polar solvent.

  Examples of the non-nitrogen-containing polar solvent include ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and triethylene glycol diethyl ether; sulfur-containing solvents such as dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, and sulfolane; Examples thereof include ester solvents such as γ-butyrolactone and cellosolve acetate; ketone solvents such as cyclohexanone and methyl ethyl ketone; and aromatic hydrocarbon solvents such as toluene and xylene. These can be used alone or in combination of two or more.

  Among the above solvents, it is preferable to select and use a solvent that can dissolve the resin to be formed. Moreover, it is preferable to use what is suitable as a solvent of curable resin composition as it is after a synthesis | combination. Among the above solvents, ketone solvents such as cyclohexanone and methyl ethyl ketone are particularly preferable in order to carry out the reaction in a highly volatile and efficient homogeneous system.

  Moreover, it is preferable that the usage-amount of a solvent shall be 0.8 to 5.0 times (mass ratio) with respect to the total amount of the raw material which synthesize | combines the urethane resin which is (A) component. If the amount used is less than 0.8 times, the viscosity at the time of synthesis tends to be too high, and the synthesis tends to be difficult due to the inability to stir, and if it exceeds 5.0 times, the reaction rate tends to decrease.

  The reaction temperature is preferably 70 to 210 ° C, more preferably 75 to 190 ° C, and particularly preferably 80 to 180 ° C. If this temperature is less than 70 ° C, the reaction time tends to be too long, and if it exceeds 210 ° C, gelation tends to occur during the reaction. The reaction time can be appropriately selected depending on the capacity of the reaction vessel and the reaction conditions employed.

  If necessary, the reaction may be performed in the presence of a catalyst such as a tertiary amine, an alkali metal, an alkaline earth metal, a metal such as tin, zinc, titanium, cobalt, or a metalloid compound.

  The blending ratio when the diol compound and the diisocyanate represented by the general formula (4) are reacted is the number average molecular weight of the urethane resin to be generated, and the terminal of the urethane resin to be generated is a hydroxyl group or an isocyanate group. It is adjusted appropriately depending on

  When the terminal of the urethane resin is a hydroxyl group, the blending ratio is preferably adjusted so that the ratio of the number of hydroxyl groups to the number of isocyanate groups (number of hydroxyl groups / isocyanate groups) is 1.01 or more, and the number average molecular weight is increased. It is preferable to adjust to 1.5 or less from a viewpoint. When the terminal of the urethane resin is a hydroxyl group, a monocarboxylic acid such as acetic acid or (meth) acrylic acid, a monoisocyanate compound such as 2-isocyanatoethyl (meth) acrylate, or a compound capable of reacting with a hydroxyl group such as an acid anhydride The terminal of the urethane resin may be modified by reacting with a terminal hydroxyl group.

  In addition, it is preferable to make the terminal of a urethane resin into an isocyanate group from a viewpoint which can introduce | transduce various frame | skeleton easily for highly functional urethane resin. When the end of the urethane resin is an isocyanate group, the ratio of the number of isocyanate groups to the number of hydroxyl groups (number of isocyanate groups / number of hydroxyl groups) is preferably adjusted to be 1.01 or more, from the viewpoint of increasing the number average molecular weight. Is preferably adjusted to 1.5 or less. By setting it as such a ratio, it becomes a urethane resin whose terminal is an isocyanate group, and can make it easy to introduce various skeletons. Examples of the compound for introducing various skeletons include compounds capable of reacting with isocyanate groups such as monohydroxy compounds, lactams, oximes, monocarboxylic acids, and divalent acid anhydrides.

  Examples of the monohydroxy compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, and the above Caprolactone or alkylene oxide adduct of each (meth) acrylate, glycerin di (meth) acrylate, trimethylol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, ditrimethylolpropane tri ( It has a monohydroxy compound having an ethylenically unsaturated group such as (meth) acrylate, allyl alcohol, 2-allyloxyethanol, or a carboxylic acid such as glycolic acid or hydroxypivalic acid. Roh hydroxy compounds. These monohydroxy compounds can be used alone or in combination of two or more. From the viewpoint of further improving the peelability of the protective layer after irradiation with actinic rays, it is preferable to use a monohydroxy compound having an ethylenically unsaturated group.

  The number average molecular weight of the urethane resin as component (A) thus obtained is preferably 7,000 to 65,000, more preferably 1,000 to 60,000, and 15,000. Particularly preferred is ˜50,000. When the number average molecular weight is less than 7,000, when the protective layer after actinic ray irradiation is peeled off, deposits or residues on the adherend surface are likely to occur, and chemical resistance tends to decrease, When the number average molecular weight exceeds 65,000, it becomes difficult to dissolve in a non-nitrogen-containing polar solvent, and it tends to be insoluble during synthesis, and the adhesiveness before irradiation with actinic rays tends to decrease.

  In the present specification, the number average molecular weight is a value measured by gel permeation chromatography (GPC) and converted using a standard polystyrene calibration curve. Further, the number average molecular weight, the weight average molecular weight, and the degree of dispersion are defined as follows.

(A) Number average molecular weight (Mn)
Mn = Σ (N _i M _i ) / ΣNi = ΣX _i M _i
(X _i = Mole fraction of molecules with molecular weight M _i = N _i / ΣN _i )
(B) Weight average molecular weight (Mw)
Mw = Σ (N _i M _i ² ) / ΣN _i M _i = ΣW _i M _i
(W _i = weight fraction of molecules of molecular weight M _i = N _i M _i / ΣN _i M _i )
(C) Molecular weight distribution (dispersion degree)
Dispersity = Mw / Mn

  Next, urethane resins having various skeletons introduced using a urethane resin whose terminal is an isocyanate group (hereinafter sometimes referred to as compound (a-1)) and a compound capable of reacting with an isocyanate group ( Another specific example when used as the component A) will be described.

  First, the urethane resin is synthesized by reacting the diol compound described above with the diisocyanate represented by the general formula (4) under the condition that the terminal is an isocyanate group. The number average molecular weight of the urethane resin synthesized here is preferably 500 to 30,000, more preferably 1,000 to 25,000, and particularly preferably 1,500 to 20,000. .

  A urethane resin having an isocyanate group at the end thus obtained, a dicarboxylic acid, a trivalent polycarboxylic acid having an acid anhydride group and a derivative thereof, or a tetravalent polycarboxylic acid having an acid anhydride group, Can be reacted to introduce an amide bond and / or an imide bond. A urethane resin into which an amide bond and / or an imide bond is introduced can further improve heat resistance and the like.

  The dicarboxylic acid is not particularly limited. For example, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecane Aliphatic dicarboxylic acids such as dionic acid, octadecanedioic acid, eicosandioic acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, dicyclohexanemethane-4,4′-dicarboxylic acid, norbornane dicarboxylic acid Aromatic dicarboxylic acids such as alicyclic dicarboxylic acids such as isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, etc. To name an acid That.

［式（５）及び（６）中、Ｒ’は、水素原子、炭素数１〜１０のアルキル基又はフェニル基を示し、Ｙ^１は、−ＣＨ_２−、−ＣＯ−、−ＳＯ_２−、又は−Ｏ−を示す。］ Although it does not specifically limit as trivalent polycarboxylic acid which has an acid anhydride group, and its derivative (s), For example, the compound represented by following General formula (5) or (6) can be mentioned.

Wherein (5) and (6), R 'is a hydrogen atom, an alkyl group or a phenyl group having 1 to 10 carbon atoms, ^{Y 1} _{is, -CH 2 -, - CO -} , - SO 2 -, Or -O- is shown. ]

  As the trivalent polycarboxylic acid having an acid anhydride group, trimellitic anhydride is particularly preferable from the viewpoint of cost.

［式（７）中、Ｙ^２は、下記式（８）：

で示される複数の基から選ばれる一種を示す。］ Moreover, although it does not specifically limit about the tetravalent polycarboxylic acid which has the said acid anhydride group, For example, the tetracarboxylic dianhydride represented by following General formula (7) can be mentioned. These can be used alone or in combination of two or more.

[In formula (7), Y ² represents the following formula (8):

1 type selected from a plurality of groups represented by ]

  The dicarboxylic acid, the trivalent polycarboxylic acid having an acid anhydride group and a derivative thereof, or the tetravalent polycarboxylic acid having an acid anhydride group can be used in combination.

  When reacting a dicarboxylic acid, a trivalent polycarboxylic acid having an acid anhydride group and a derivative thereof, or a tetravalent polycarboxylic acid having an acid anhydride group, an isocyanate compound other than the above compound (a-1) (Hereinafter, referred to as “compound (a-2)”) can also be used. The compound (a-2) is not particularly limited as long as it is an isocyanate compound other than the compound (a-1). For example, diisocyanates represented by the above general formula (3), trivalent or higher polyisocyanates Is mentioned. These can be used individually by 1 type or in combination of 2 or more types.

  Moreover, in this embodiment, an amine compound can also be used together with the said isocyanate compound. As an amine compound, the compound which converted the isocyanate group in the said isocyanate compound into the amino group is mentioned. Conversion of an isocyanate group to an amino group can be performed by a known method. The preferred range of the number average molecular weight of the amine compound is the same as that of the above compound (a-1).

  As compound (a-2), it is preferable that 50-100 mass% of the total amount is aromatic polyisocyanate, and considering the balance of solubility, mechanical properties, cost, etc., 4,4′-diphenylmethane Diisocyanate is particularly preferred.

  When the compound (a-1) and the compound (a-2) are used in combination, the equivalent ratio of the compound (a-1) / the compound (a-2) is 0.1 / 0.9 to 0.9 / 0. .1 is preferable, 0.2 / 0.8 to 0.8 / 0.2 is more preferable, and 0.3 / 0.7 to 0.7 / 0.3 is particularly preferable. preferable. When the equivalent ratio is within this range, good adhesion to an adherend can be obtained.

  The blending ratio of the dicarboxylic acid, the trivalent polycarboxylic acid having an acid anhydride group or a derivative thereof, and / or the tetravalent polycarboxylic acid having an acid anhydride group is the total number of isocyanate groups in the isocyanate compound. The ratio of the total number of carboxyl groups and anhydride groups (total number of carboxyl groups and anhydride groups / total number of isocyanate groups) is preferably 0.6 to 1.4, 0.7 -1.3 is more preferable, and 0.8-1.2 is particularly preferable. When this ratio is less than 0.6 or exceeds 1.4, it tends to be difficult to increase the number average molecular weight of the urethane resin containing an amide bond and / or an imide bond.

  The urethane resin into which the amide bond and / or imide bond thus obtained can be introduced can be used as the component (A). The number average molecular weight of the urethane resin into which an amide bond and / or an imide bond are introduced is preferably 7,000-65,000, more preferably 10,000-60,000, and 15,000-50. Is particularly preferred. When the number average molecular weight is less than 7,000, when the protective layer after actinic ray irradiation is peeled off, deposits or residues on the adherend surface are likely to occur, and chemical resistance tends to decrease. When the number average molecular weight exceeds 65,000, it is difficult to dissolve in a non-nitrogen-containing polar solvent, and it tends to be insoluble during synthesis, and the adhesiveness before irradiation with actinic rays tends to be lowered.

  As the urethane resin of the component (A) used in the curable resin composition of the present invention, two or more types of urethane resins having different structures can be used in combination. Two or more urethane resins having the same structure and different number average molecular weights may be mixed and used. At this time, it is preferable that the number average molecular weight measured by GPC method is within the above-mentioned range for all of the two or more urethane resins to be mixed. The mixing ratio when mixing two or more urethane resins is not particularly limited. Further, the concentration of the resin solution can be selected without limitation.

<(B) component: a photopolymerizable compound having one or more ethylenically unsaturated groups in the molecule>
(B) As a photopolymerizable compound having one or more ethylenically unsaturated groups in the molecule, for example, a bisphenol A (meth) acrylate compound; a polyhydric alcohol is reacted with an α, β-unsaturated carboxylic acid Compounds obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid; urethane monomers or urethane oligomers such as (meth) acrylate compounds having a urethane bond. Besides these, nonylphenoxy polyoxyethylene acrylate; γ-chloro-β-hydroxypropyl-β ′-(meth) acryloyloxyethyl-o-phthalate, β-hydroxyalkyl-β ′-(meth) acryloyloxyalkyl- Examples thereof include phthalic acid-based compounds such as o-phthalate; (meth) acrylic acid alkyl esters, and EO-modified nonylphenyl (meth) acrylate. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of bisphenol A-based (meth) acrylate compounds include 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxypolypropoxy). ) Phenyl) propane, 2,2-bis (4-((meth) acryloxypolybutoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane. It is done.

  Examples of 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxy) phenyl) propane, 2,2- Bis (4-((meth) acryloxytriethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetraethoxy) phenyl) propane, 2,2-bis (4-((meth)) Acryloxypentaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptaethoxy) phenyl) propane 2,2-bis (4-((meth) acryloxyoctaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxy nonaethoxy) ) Phenyl) propane, 2,2-bis (4-((meth) acryloxydecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyundecaethoxy) phenyl) propane, 2, 2-bis (4-((meth) acryloxydodecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytridecaethoxy) phenyl) propane, 2,2-bis (4- ( (Meth) acryloxytetradecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecaethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxyhexa) Decaethoxy) phenyl) propane. Of these, 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is commercially available as BPE-500 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.). 4- (Methacryloxypentadecaethoxy) phenyl) propane is commercially available as BPE-1300 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.). These can be used individually by 1 type or in combination of 2 or more types.

  Examples of 2,2-bis (4-((meth) acryloxypolypropoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydipropoxy) phenyl) propane, 2,2- Bis (4-((meth) acryloxytripropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetrapropoxy) phenyl) propane, 2,2-bis (4-((meth)) Acryloxypentapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptapropoxy) phenyl) propane 2,2-bis (4-((meth) acryloxyoctapropoxy) phenyl) propane, 2,2-bis (4-((meth) acrylic) Xinonapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxydecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyundecapropoxy) phenyl) propane 2,2-bis (4-((meth) acryloxydodecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytridecapropoxy) phenyl) propane, 2,2-bis ( 4-((meth) acryloxytetradecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecapropoxy) phenyl) propane and 2,2-bis (4-((meth)) Acryloxyhexadecapropoxy) phenyl) propane. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxyoctapropoxy) phenyl) propane, Examples include 2,2-bis (4-((meth) acryloxytetraethoxytetrapropoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxyhexaethoxyhexapropoxy) phenyl) propane. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of the compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid include 2 to 20 polyethylene glycol di (meth) acrylate propylene groups having 2 to 20 ethylene groups. Polypropylene glycol di (meth) acrylate, polyethylene polypropylene glycol di (meth) acrylate having 2 to 20 ethylene groups and 2 to 20 propylene groups, trimethylolpropane di (meth) acrylate, trimethylol Propane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylolpropane tri (meth) acrylate, EO / PO modified trimethylolpropane tri (meth) acrylate, tetramethylol methanetri (meth) acrylate Examples include relate, tetramethylolmethane tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. These can be used individually by 1 type or in combination of 2 or more types.

“EO” refers to “ethylene oxide”, and “PO” refers to “propylene oxide”. “EO modified” means having a block structure of ethylene oxide units (—CH ₂ CH ₂ O—), and “PO modified” means propylene oxide units (—CH ₂ CH (CH ₃ ) O—). It means having a block structure.

  Examples of the compound obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid include trimethylolpropane triglycidyl ether tri (meth) acrylate, 2,2-bis (4- (meth) acryloxy- 2-hydroxy-propyloxy) phenyl; an epoxy acrylate compound obtained by reacting an epoxy resin such as a novolak-type epoxy resin, a bisphenol-type epoxy resin, or a salicylaldehyde-type epoxy resin with an α, β-unsaturated carboxylic acid. . Examples of the α, β-unsaturated carboxylic acid include (meth) acrylic acid. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of the urethane monomer or urethane oligomer include (meth) acrylic monomers having an OH group at the β-position, isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, and 1,6-hexamethylene diisocyanate. Addition reaction product with diisocyanate compound; tris ((meth) acryloxytetraethylene glycol isocyanate) hexamethylene isocyanurate; EO-modified urethane di (meth) acrylate; EO or PO-modified urethane di (meth) acrylate; carboxyl group-containing urethane (meth) Acrylate; (meth) acrylic monomer having OH group at β-position, diisocyanate compound, polyether diols, polyester diols, polycaprolactone diols, Addition reaction products with diol compounds such as silicone diols; polyfunctional (meth) acrylate compounds having hydroxyl groups such as pentaerythritol tri (meth) acrylate and dipentaerythritol pentaacrylate; polymethylene diisocyanates such as hexamethylene diisocyanate; Examples include addition reaction products with diisocyanate compounds such as arylene diisocyanate such as range isocyanate and cycloalkylene diisocyanate such as isophorone diisocyanate. From the viewpoint of further improving the adhesion (peel strength) before irradiation with actinic rays, an ethylenically unsaturated group and at least one skeleton of a polycarbonate skeleton, a polyether skeleton, a polyester skeleton, a polycaprolactone diol skeleton, and a silicone skeleton are included. The compound which has is preferable. Examples of such a compound include an addition reaction between a (meth) acrylic monomer having an OH group at the β-position, a diisocyanate compound, polycarbonate diols, polyether diols, polyester diols, polycaprolactone diols, and silicone diols. Can be obtained. These can be used individually by 1 type or in combination of 2 or more types.

  The component (B) preferably contains a compound having three or more ethylenically unsaturated groups in the molecule from the viewpoint of further improving the peelability of the protective layer after irradiation with actinic rays. It is more preferable to contain a compound having one or more ethylenically unsaturated groups, and it is particularly preferable to contain a compound having six or more ethylenically unsaturated groups in the molecule. From the viewpoint of storage stability, the number of ethylenically unsaturated groups in the molecule is preferably 20 or less. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of the compound having three or more ethylenically unsaturated groups in the molecule include trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO・ PO-modified trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate, pentaerythritol Polyfunctional (meth) acrylate compounds having a hydroxyl group such as tri (meth) acrylate and dipentaerythritol pentaacrylate and polyethylene such as hexamethylene diisocyanate Addition reaction products with diisocyanate compounds such as arylene diisocyanates such as diisocyanate and tolylene diisocyanate, cycloalkylene diisocyanates such as isophorone diisocyanate, epoxy resins such as novolac type epoxy resins, bisphenol type epoxy resins, salicylaldehyde type epoxy resins and (meth) Examples thereof include an epoxy acrylate compound obtained by reacting with acrylic acid.

  Furthermore, examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, and (meth) acrylic acid 2-ethylhexyl ester. It is done. These can be used individually by 1 type or in combination of 2 or more types.

［式（１０）中、Ｒは、炭素数１〜１８のアルキレン基を示し、Ｒ^２は、水素原子又はメチル基を示し、Ｘは、２価の有機基を示し、Ｚは、２〜６価の有機基を示し、ｍ及びｎはそれぞれ独立に１〜３０の整数を示し、ｐ及びｑはそれぞれ独立に１〜５の整数を示す。なお、複数存在するＲ、Ｒ^２、Ｘ及びＹはそれぞれ同一でも異なっていてもよい。また、ｎが２以上の場合、複数存在するｍはそれぞれ同一でも異なっていてもよい。］ In addition, the adhesiveness of the protective layer before irradiation with actinic rays can be further improved, and the surface tackiness of the protective layer at room temperature (stickiness on the surface opposite to the surface to be adhered to the adherend) can be reduced, and From the viewpoint of improving chemical properties and water resistance, a compound having a polycarbonate skeleton is preferred as the component (B). The reason why the compound having a polycarbonate skeleton has the above effect is that it has high crystallinity at room temperature and crystallinity collapses at high temperature and becomes amorphous. The present inventors consider that the film exhibits high adhesion to the adherend when heated (thermocompression bonding). In addition, it is considered that the compound having a polycarbonate skeleton is excellent in compatibility with the urethane resin that is the component (A), which also enables high adhesion to the adherend. Examples of the compound having a polycarbonate skeleton as the component (B) include a compound represented by the following general formula (10).

[In the formula (10), R represents an alkylene group having 1 to 18 carbon atoms, R ² represents a hydrogen atom or a methyl group, X represents a divalent organic group, and Z represents 2 to 6 A valent organic group, m and n each independently represent an integer of 1 to 30, and p and q each independently represents an integer of 1 to 5. A plurality of R, R ² , X and Y may be the same or different. When n is 2 or more, a plurality of m may be the same or different. ]

  The compound represented by the general formula (10) includes a diisocyanate compound represented by the following general formula (9), 2-hydroxyethyl (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol penta (meta). ) It can be obtained by reacting a compound having an ethylenically unsaturated group such as acrylate and a hydroxyl group.

［式（９）中、Ｒは炭素数１〜１８のアルキレン基を示し、Ｘは２価の有機基を示し、ｍ及びｎはそれぞれ独立に１〜３０の整数を示す。なお、複数存在するＲ及びＸはそれぞれ同一でも異なっていてもよい。また、ｎが２以上の場合、複数存在するｍはそれぞれ同一でも異なっていてもよい。］

[In Formula (9), R shows a C1-C18 alkylene group, X shows a bivalent organic group, m and n show the integer of 1-30 each independently. A plurality of R and X may be the same or different. When n is 2 or more, a plurality of m may be the same or different. ]

［式（１１）中、Ｒは、炭素数１〜１８のアルキレン基を示し、Ｒ^２は、水素原子又はメチル基を示し、Ｘ及びＺは、それぞれ独立に２価の有機基を示し、ｍ及びｎはそれぞれ独立に１〜３０の整数を示す。なお、複数存在するＲ、Ｒ^２、Ｘ及びＹはそれぞれ同一でも異なっていてもよい。また、ｎが２以上の場合、複数存在するｍはそれぞれ同一でも異なっていてもよい。］ Among these components (B), in particular, a compound having three or more ethylenically unsaturated groups and a polycarbonate skeleton in the molecule from the viewpoint of improving both the adhesiveness before irradiation with actinic rays and the peelability after irradiation with actinic rays. Is preferably used. Moreover, it is also preferable to use together the compound which has 3 or more ethylenically unsaturated groups in a molecule | numerator, and the compound which has 1 or more and 2 or less ethylenically unsaturated groups and polycarbonate frame | skeleton in a molecule | numerator. As a compound having one or more and two or less ethylenically unsaturated groups and a polycarbonate skeleton in the molecule, the compound represented by the above general formula (10), wherein p and q are 1, the following general formula (11) The compound represented by these is mentioned.

[In Formula (11), R represents an alkylene group having 1 to 18 carbon atoms, R ² represents a hydrogen atom or a methyl group, X and Z each independently represent a divalent organic group, m And n each independently represents an integer of 1 to 30. A plurality of R, R ² , X and Y may be the same or different. When n is 2 or more, a plurality of m may be the same or different. ]

  When using a compound having 3 or more ethylenically unsaturated groups in the molecule and a compound having 1 or more and 2 or less ethylenically unsaturated groups and a polycarbonate skeleton in the molecule, 3 or more in the molecule The content of the compound having an ethylenically unsaturated group is preferably 1 to 100 parts by mass, more preferably 5 to 30 parts by mass with respect to 100 parts by mass of the component (A). Particularly preferred is 25 parts by mass.

  Moreover, it is preferable that content of the compound which has 1 or more and 2 or less ethylenically unsaturated groups and polycarbonate frame | skeleton in a molecule | numerator is 5-100 mass parts with respect to 100 mass parts of (A) component, More preferably, it is 10-70 mass parts, and it is especially preferable that it is 30-55 mass parts.

  The photopolymerizable compound as component (B) preferably has a number average molecular weight of 500 to 6,000, more preferably 1,000 to 5,000, and 1,500 to 5,000. It is particularly preferred. If the number average molecular weight is less than 500, the photocured film is peeled off, and there is a tendency for deposits to remain on the wafer. If the number average molecular weight exceeds 6,000, the adhesiveness before irradiation with actinic rays is reduced, and photocuring is performed. Does not proceed sufficiently, and the peelability tends to decrease.

  The content of the component (B) in the curable resin composition of the present invention is preferably 10 to 200 parts by mass and more preferably 20 to 100 parts by mass with respect to 100 parts by mass of the component (A). 40 to 80 parts by mass is particularly preferable. When the content is less than 5 parts by mass, the photocurability becomes insufficient and the peelability tends to decrease. When the content exceeds 200 parts by mass, the adhesiveness before irradiation with actinic rays decreases or the film formability. However, the cured film tends to be difficult to peel off.

<(C) component: photopolymerization initiator>
Specific examples of the photopolymerization initiator include, for example, benzophenone, 4,4′-bis (dimethylamino) benzophenone (Michler ketone), 4,4′-bis (diethylamino) benzophenone, 4-methoxy-4′-dimethylaminobenzophenone. 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-morpholinophenone) -butanone-1,2-ethylanthraquinone, Aromatic ketones such as phenanthrenequinone, quinones such as alkyl anthraquinone, benzoin ethers such as benzoin methyl ether, benzoin ethyl ether and benzoin phenyl ether, benzoins such as methyl benzoin and ethyl benzoin, benzyl derivatives such as benzyl dimethyl ketal, - phenyl acridine, 1,7-bis (9,9'-acridinyl) acridine derivatives such as heptane, N- phenylglycine, N- phenylglycine derivatives, coumarin-based compounds. These can be used individually by 1 type or in combination of 2 or more types.

  The content of the component (C) in the curable resin composition of the present invention is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B). It is preferable that it is 5-10 mass parts, and it is especially preferable that it is 1-5 mass parts. When this content is less than 0.1 parts by mass, the photocuring tends to be insufficient and the protective layer tends to be difficult to peel, and when it exceeds 30 parts by mass, the surface of the adherend tends to be contaminated.

<Other ingredients>
The curable resin composition of this invention can contain an epoxy resin as (D) component. Although it does not specifically limit as an epoxy resin, Epoxy resins, such as a bisphenol A type, a bisphenol F type, a biphenyl type, an aliphatic alkyl type, a novolak type, can be used. Examples of the epoxy resin include bisphenol A type epoxy resin (trade name Epicoat 828 manufactured by Yuka Shell Epoxy Co., Ltd.), bisphenol F type epoxy resin (trade name YDF-170 manufactured by Toto Kasei Co., Ltd.), Phenol novolac type epoxy resin (trade name Epicoat 152, 154 of Yuka Shell Epoxy Co., Ltd .; trade name EPPN-201 manufactured by Nippon Kayaku Co., Ltd .; trade name DEN-438 manufactured by Dow Chemical Co., Ltd.), o -Cresol novolac type epoxy resins (trade names EOCN-125S, 103S, 104S, etc., manufactured by Nippon Kayaku Co., Ltd.), polyfunctional epoxy resins (trade names, Epon 1031S, manufactured by Yuka Shell Epoxy Co., Ltd .; Ciba Specialty Chemicals) Product name Araldite 0163 manufactured by Co., Ltd .; Product name Denacor manufactured by Nagase Kasei Co., Ltd. X-611, EX-614, EX-614B, EX-622, EX-512, EX-521, EX-421, EX-411, EX-321, etc.), amine type epoxy resin (Oilized Shell Epoxy Co., Ltd.) Product name Epicoat 604; Product name YH434 manufactured by Tohto Kasei Co., Ltd. Product names TETRAD-X and TERRAD-C manufactured by Mitsubishi Gas Chemical Company, Inc. Product names GAN manufactured by Nippon Kayaku Co., Ltd .; Sumitomo Chemical (Trade name ELM-120 manufactured by Co., Ltd.), epoxy resin containing heterocyclic ring (trade name Araldite PT810 manufactured by Ciba Specialty Chemicals Co., Ltd.), alicyclic epoxy resin (ERL4234, 4299 manufactured by UCC) 4221, 4206, etc.), epoxidized polybudadiene obtained by partially epoxidizing polybutadiene (product PB-3600 manufactured by Daicel Chemical Industries, Ltd.) Nippon Soda Co., Ltd. trade name BF-1000, etc.), novolak type epoxy resins having a biphenyl skeleton, and aliphatic alkyl type epoxy resins, which can be used alone or in combination of two or more. Among these, those that are soluble in an organic solvent are preferable from the viewpoint of maintaining the transparency of the curable resin composition, and epoxidized polybutadiene obtained by partially epoxidizing polybutadiene is more preferable.

  Moreover, the curable resin composition of this invention can contain an epoxy resin hardening | curing agent as (E) component. Epoxy resin curing agents include imidazole, hydrazide, boron trifluoride-amine complexes, sulfonium salts, amine imides, polyamine salts, dicyandiamide, and these curing agents coated with polyurethane or polyester polymer materials. And microencapsulated. These can be used individually by 1 type or in combination of 2 or more types. Among these, in order to suppress thermal polymerization of the photopolymerizable compound at the time of epoxy resin thermal curing in the thermocompression bonding step, suppression of thermal polymerization of the epoxy resin by heating in the drying step when the curable resin composition is applied, The reaction start temperature is preferably 80 ° C to 150 ° C, more preferably 110 to 130 ° C. Examples of such epoxy resin curing agents include latent curing agents such as microcapsule type and heat dissolution type, and Novacure series (manufactured by Asahi Kasei Chemicals Co., Ltd.) as a typical product of microcapsule type A typical product of the mold is the Amicure series (manufactured by Ajinomoto Fine Techno).

  When the microcapsule type curing agent is heated to a predetermined temperature, the surrounding resin covering the curing agent is dissolved, the curing agent is diffused into the resin, and reaction with the epoxy resin is started. The heat-dissolving curing agent is a solid at room temperature, but dissolves when heated to a predetermined temperature and starts to react with the epoxy resin.

  The curable resin composition of the present invention can contain a filler (F) as necessary. There is no restriction | limiting in particular as a filler, For example, metal fillers, such as silver powder, gold powder, copper powder, nickel powder; Alumina, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, oxidation Examples thereof include inorganic fillers such as calcium, magnesium oxide, aluminum oxide, aluminum nitride, crystalline silica, amorphous silica, boron nitride, titania, glass, iron oxide, and ceramics; and organic fillers such as carbon and rubber fillers. The shape of the filler is not particularly limited.

  The filler can be used properly according to the desired function. For example, the metal filler is added for the purpose of imparting conductivity, thermal conductivity, thixotropy, etc. to the curable resin composition; the nonmetallic inorganic filler is thermally conductive, low thermal expansion, It is added for the purpose of imparting low hygroscopicity and the like; the organic filler is added for the purpose of imparting toughness and the like to the curable resin composition. These fillers can be used alone or in combination of two or more.

  Further, the curable resin composition of the present invention, if necessary, a plasticizer such as p-toluenesulfonic acid amide, a pigment, a filler, an antifoaming agent, a coupling agent, a stabilizer, an adhesion imparting agent, A leveling agent, a peeling accelerator, an antioxidant, a thermal crosslinking agent and the like can be contained.

  Next, an adhesion method and a peeling method using the curable resin composition of the present invention will be described below.

(Adhesion method)
The solution of the curable resin composition can be used as a protective layer by applying or dropping the solution on the adherend to a desired thickness. Moreover, it can also be used as a film-form protective layer by shape | molding a curable resin composition in a film form and affixing on a to-be-adhered body. The method and conditions for applying, dripping and pasting are not particularly limited. Examples of the adherend include a wafer on which a circuit is formed, a glass substrate, a ceramic substrate, an aluminum substrate, and an organic material substrate. The curable resin composition of the present invention is particularly preferable for a wafer.

  Moreover, a curable resin film comprising a support film and a curable resin composition layer made of the curable resin composition of the present invention formed on the support film is prepared, and the curable resin composition layer of this film is prepared. You may affix on a to-be-adhered body. Examples of the support film include polymer films such as polyethylene terephthalate, polypropylene, polyethylene, and polyester.

  When the solution of the curable resin composition is used directly, it is preferable to dry the solvent at 60 to 120 ° C after application and dropping, and more preferably at 80 to 100 ° C. When it exceeds 120 ° C., it is thermally cured and the adhesiveness is lowered, and when it is 60 ° C. or lower, the solvent may not be completely dried and the adhesiveness may be lowered.

  Also in the case of producing a film-like protective layer, it is preferable to perform the treatment under the above temperature conditions for the same reason.

  The thermocompression bonding is preferably performed at 80 to 150 ° C, more preferably 100 to 130 ° C. If it exceeds 150 ° C., thermal polymerization of the photocurable component may start, and the adhesiveness may decrease. If it is less than 80 ° C., the wettability of the curable resin composition may be poor, and the adhesiveness may decrease. is there.

  The pressure and time during thermocompression bonding can be arbitrarily adjusted by changing the types of components constituting the curable resin composition. The pressure bonding temperature needs to be a temperature at which thermosetting of the component (B) can be suppressed.

(Peeling method)
Next, the protective layer after the thermocompression bonding is irradiated with actinic rays such as ultraviolet rays, and the protective layer after photocuring is peeled from the substrate by reducing the adhesiveness of the protective layer by photocuring.

  Here, as the light source of actinic light, a known light source such as a carbon arc lamp, a mercury vapor arc lamp, a high-pressure mercury lamp, a xenon lamp, or the like that effectively emits ultraviolet rays is used. Moreover, what can radiate | emit visible light effectively, such as a flood bulb for photography, a solar lamp, can be used.

  Moreover, according to the curable resin composition of this invention, the protective layer which has the adhesiveness outstanding on the to-be-adhered body can be formed. This protective layer can be easily removed by irradiation with actinic rays. The curable resin composition of the present invention capable of forming such a protective film is suitable for protecting a portion not subjected to plating when a plating film is formed on a surface to be plated on a substrate such as a wafer.

(Plating method)
The plating method of the present invention comprises a protective layer forming step of forming a protective layer comprising the curable resin composition of the present invention on one surface of an adherend, and a surface opposite to the protective layer forming surface of the adherend. And a plating step of forming a plating film, and a peeling step of peeling the protective layer after photocuring from the adherend by irradiating the protective layer with actinic rays after the plating step and photocuring.

  Here, FIGS. 1A to 1D are a series of process diagrams showing an example of the plating method of the present invention. As shown to Fig.1 (a), the protective layer 2 which consists of the said curable resin composition of this invention is first formed in the back surface side of the wafer 1 (protective layer formation process).

  In the protective layer forming step, the protective layer 2 can be formed by applying, dripping or pasting the curable resin composition of the present invention on the wafer 1 to a desired thickness. The method and conditions for applying, dripping and pasting are not particularly limited.

  When forming the protective layer 2 by coating or dripping, for example, a solvent is added to the curable resin composition described above to form a liquid, which is applied or dripped onto the back surface of the wafer 1 and dried to remove the solvent. Thus, the protective layer 2 can be formed.

  Examples of the solvent include ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and triethylene glycol diethyl ether; sulfur-containing solvents such as dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, and sulfolane; γ-butyrolactone And ester solvents such as cellosolve acetate; ketone solvents such as cyclohexanone and methyl ethyl ketone; and aromatic hydrocarbon solvents such as toluene and xylene. These can be used alone or in combination of two or more.

  Further, when the protective layer 2 is formed by pasting, a film-like adhesive in which the curable resin composition of the present invention is formed in advance like a resin composition layer of the curable resin film is used. It can be attached to the wafer 1 using a film mounter or the like.

  The thickness of the protective layer 2 is preferably 5 to 200 μm, more preferably 10 to 100 μm, and particularly preferably 15 to 80 μm from the viewpoint of adhesion and warpage prevention.

  The wafer to which the plating method of the present invention can be applied is not particularly limited, and examples thereof include semiconductor substrates such as silicon wafers and GaAs wafers. Moreover, although it does not specifically limit about the thickness of a wafer, For example, the thing of 100 micrometers-1000 micrometers is used. Further, bumps may or may not be formed on the surface of the wafer. When the bump is formed, the height is not particularly limited, but is, for example, 10 to 200 μm.

  After the protective layer 2 is formed on the back surface of the wafer 1 by the protective layer forming step, a plating film 3 is formed on the surface opposite to the back surface of the wafer 1 as shown in FIG. ). The plating treatment can be performed by a known method. In the case of a wafer having a conductor pattern on both sides, a plating film can be formed only on the conductor pattern on the surface requiring plating by covering the conductor pattern on the surface not requiring plating with the protective layer. Hereinafter, the method of the plating process will be specifically described.

  First, degreasing is performed as a pretreatment for the plating treatment. Degreasing is a process of removing oil stains on the surface of the conductor pattern. For degreasing, a solvent, an alkaline aqueous solution or an acidic aqueous solution can be used, but an alkaline aqueous solution is more preferable. In order to make the surface of the conductor pattern uniform after degreasing, the surface of the conductor pattern is usually mildly etched with an etching solution such as a sulfuric acid hydrogen peroxide aqueous solution. Further, after washing with water, the surface of the conductor pattern may be washed with a dilute sulfuric acid aqueous solution or the like. Next, after washing with water, for example, a catalyst is formed only on the conductor pattern with a substitution type zinc catalyst solution (zincate) or the like. After washing with water, the wafer is immersed in an electroless nickel plating solution to form an electroless nickel plating film in the conductor pattern region.

Next, a displacement gold plating step is performed. The displacement gold plating step is performed by immersing the wafer subjected to the above-described electroless nickel plating in water and then immersing it in a displacement gold plating solution. The displacement gold plating solution is gold plated on the nickel plating film by a substitution reaction (Ni → Ni ²⁺ + 2e ⁻ , 2Au ⁺ + 2e ⁻ → 2Au) between nickel formed as a plating film and gold ions in the gold plating solution. If it was conventionally used in order to form a membrane | film | coat, it will not specifically limit. Examples of such substitutional gold plating solutions include gold cyanide salts (cyanide gold ion source) such as sodium gold cyanide or potassium gold cyanide, gold sulfite, gold thiosulfate or chloroaurate. Non-cyanide gold salts (non-cyanide gold ion sources), and complexing agents such as sulfites, thiosulfates, thiomalates or carboxylates can be mentioned. Furthermore, an appropriate amount of other various additives usually used in a displacement gold plating solution can also be included.

  As shown in FIG. 1 (c), the protective layer 2 is irradiated with actinic rays such as ultraviolet rays (UV) to protect the wafer 1 with the protective layer 2 on which the plating film 3 is formed as described above, and is protected by photocuring. Reduce the adhesion of the layer 22. Then, as shown in FIG.1 (d), the protective layer 22 after photocuring is peeled from the wafer 1 (peeling process).

  Here, as the light source of actinic light, a known light source such as a carbon arc lamp, a mercury vapor arc lamp, a high-pressure mercury lamp, a xenon lamp, or the like that effectively emits ultraviolet rays is used. Moreover, what can radiate | emit visible light effectively, such as a flood bulb for photography, a solar lamp, can be used.

  The method for peeling the protective layer 22 after photocuring from the wafer 1 is not particularly limited, but preferably, a method of attaching an adhesive tape to the protective layer 22 and peeling the protective layer 22 from the wafer 1 together with the adhesive tape is used. Thereby, the protective layer 22 can be peeled efficiently and reliably. Moreover, if an adhesive tape permeate | transmits actinic light, after affixing an adhesive tape to the protective layer 2, you may irradiate actinic light. Furthermore, in this embodiment, the curable resin film which concerns on this invention provided with a support film / resin composition layer / adhesive tape in this order can be used.

  Further, the curable resin composition of the present invention includes a protective layer forming step of forming a protective layer comprising the curable resin composition of the present invention on the circuit forming surface side of the wafer in the wafer dicing method, and circuit formation of the wafer. A dicing sheet attaching step for attaching a dicing sheet to the surface opposite to the surface, a dicing step for dicing the wafer together with the protective layer from the circuit forming surface side of the wafer, and irradiating the cut protective layer with actinic rays Then, it can be photocured and used in a dicing method having a peeling step of peeling off the protective layer after photocuring from a wafer. Moreover, the curable resin composition of this invention can also be applied as a soldering resist for wiring boards.

  As mentioned above, although preferred embodiment of this invention was described, this invention is not restrict | limited to this.

  Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited thereto.

(Synthesis example)
<Production of component (A-1)>
To a 3 L four-necked flask equipped with a stirrer, a condenser tube with an oil separator, a nitrogen inlet tube and a thermometer, polybutadienediol (manufactured by Nippon Soda Co., Ltd., trade name “G-1000”, number average molecular weight: 1,250 to 1,650) 260 g, 1,5-naphthalene diisocyanate 40 g, and cyclohexanone 300 g were charged, heated to 80 ° C. to 90 ° C. with stirring under a nitrogen gas stream, and reacted for 9 hours. Subsequently, 3.8 g of 2-hydroxyethyl acrylate was added, and the reaction was carried out until the absorption of isocyanate disappeared by infrared spectroscopic analysis to obtain a urethane resin having a number average molecular weight of 18,000. The obtained resin was diluted with cyclohexanone to obtain a urethane resin solution having a nonvolatile content of 50% by mass.

<Production of component (A-2)>
Polycarbonate diol (manufactured by Asahi Kasei Chemicals, trade name “PCDL T-5651”, number average molecular weight (Mn): 3 L four-necked flask equipped with stirrer, condenser with oil separator, nitrogen inlet tube and thermometer About 1,000, corresponding to the compound in which R is an alkylene group having 5 or 6 carbon atoms in the above general formula (2). 108.3 g, polycarbonate diol (manufactured by Asahi Kasei Chemicals Co., Ltd., trade name “PCDL T-5552”) , Number average molecular weight: about 2,000) 129.0 g, 1,5-naphthalene diisocyanate 40 g, cyclohexanone 300 g were charged, heated to 80 ° C. to 90 ° C. with stirring under a nitrogen gas stream, and reacted for 9 hours. . Subsequently, 3.8 g of 2-hydroxyethyl acrylate was added, and the reaction was performed until the absorption of isocyanate disappeared by infrared spectroscopic analysis to obtain a urethane resin having a number average molecular weight of 17,000. The obtained resin was diluted with cyclohexanone to obtain a urethane resin solution having a nonvolatile content of 50% by mass.

<Production of component (A-3)>
To a 3 L four-necked flask equipped with a stirrer, a condenser tube with an oil separator, a nitrogen inlet tube and a thermometer, polycarbonate diol (trade name “PCDL T-5651” manufactured by Asahi Kasei Chemicals Corporation) 108.26 g, polycarbonate diol ( Asahi Kasei Chemicals Co., Ltd., trade name “PCDL T-5552”) 129.01 g, polybutadiene diol (manufactured by Nippon Soda Co., Ltd., trade name “G-1000”) 70.49 g, 1,5-naphthalene diisocyanate 50.8 g, cyclohexanone 300 g Was heated to 80 ° C. to 90 ° C. with stirring under a nitrogen gas stream and reacted for 9 hours. Subsequently, 5.1 g of 2-hydroxyethyl acrylate was added, and the reaction was performed until the absorption of isocyanate disappeared by infrared spectroscopic analysis to obtain a urethane resin having a number average molecular weight of 20,000. The obtained resin was diluted with cyclohexanone to obtain a urethane resin solution having a nonvolatile content of 50% by mass.

<Alternative (A) component: Preparation of component (A-4)>
6. Into a 300 mL four-neck separable flask equipped with a stirrer, thermometer, nitrogen inlet tube and Dean Stark trap, decamethylene bis trimellitate dianhydride (trade name “DBTA-KU”, manufactured by Kurokin Kasei Co., Ltd.) 3 g (0.014 mol), benzophenone tetracarboxylic dianhydride (BTDA) 18.05 g (0.056 mol), [3,4-bis (1-aminoheptyl) -6-hexyl-5- (1-octenyl) ] 38.86 g (0.07 mol) of cyclohexene (manufactured by Cognis Japan, trade name “Versamine 551”) and 164 g of cyclohexanone were added and stirred at 40 ° C. for 15 minutes. Next, the temperature was raised to 150 ° C., and the mixture was heated to reflux for 3 hours, and then dissolved. After the dissolution, the solid content was adjusted to 30% while stirring at 40 ° C. to obtain a cyclohexanone solution of a polyimide resin having a number average molecular weight of 20,000.

<Production of component (B-1)>
Polycarbonate diol (manufactured by Asahi Kasei Chemicals Corporation, trade name “PCDL T-6001”, number average molecular weight: about 1,000, corresponding to the compound in which R is an alkylene group having 6 carbon atoms in the above general formula (2)). 100 g, 38.6 g of m-xylylene diisocyanate, and 70.0 g of cyclohexanone were charged into a reaction vessel, heated to 90 ° C. to 100 ° C. with stirring under a nitrogen gas stream, and reacted for 1 hour. Next, 23.8 g of 2-hydroxyethyl acrylate was added, and the reaction was carried out until the absorption of isocyanate disappeared by infrared spectroscopic analysis to obtain a polyurethane acrylate solution having a number average molecular weight of 2,000.

<Production of (B-2) Component>
Polycarbonate diol (trade name “PCDL T-6001” manufactured by Asahi Kasei Chemicals Co., Ltd.) 100 g, 1,5-naphthalene diisocyanate 43.2 g, cyclohexanone 72.0 g were charged into a reaction vessel and stirred at 90 ° C. under a nitrogen gas stream. The mixture was heated to ˜100 ° C. and reacted for 1 hour. Subsequently, 24.3 g of 2-hydroxyethyl acrylate was added, and the reaction was carried out until the absorption of isocyanate disappeared by infrared spectroscopic analysis to obtain a polyurethane acrylate solution having a number average molecular weight of 2,000.

<Preparation of (B-3) component>
A urethane acrylate “UN-904” (manufactured by Negami Kogyo Co., Ltd., trade name, weight average molecular weight 4,900, number average molecular weight 2,000) having an average number of ethylenically unsaturated groups per molecule of 10 was prepared.

<Preparation of (B-4) component>
An acrylate “light acrylate DPE-6A” (dipentaerythritol hexaacrylate, trade name, manufactured by Kyoeisha Chemical Co., Ltd.) having an average number of ethylenically unsaturated groups per molecule of 6 was prepared.

In addition, the number average molecular weight of the synthesized urethane resin was converted from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The measurement conditions for GPC are shown below.
(GPC conditions)
Pump: Hitachi L-6000 type [manufactured by Hitachi, Ltd.]
Detector: Hitachi L-3300 RI [manufactured by Hitachi, Ltd.]
Column: Gelpack GL-R420 + Gelpack GL-R430 + Gelpack GL-R430 (3 in total) (manufactured by Hitachi Chemical Co., Ltd., trade name)
Eluent: THF
Sample concentration: 250 mg / 5 mL
Injection volume: 50 μL
Pressure: 441 Pa (45 kgf / cm ² )
Flow rate: 1.75 mL / min

<Preparation of curable resin composition>
Example 1
The above (A-1) urethane resin solution 12.6 g (solid content: 6.3 g) and the above (B-1) polyurethane acrylate solution 3.9 g (solid content: 2.7 g) were added to (B-3) “UN -904 "1.0 g, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one (Ciba Specialty Chemicals, trade name" I- "as component (C) 907 ") and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (manufactured by Ciba Specialty Chemicals, trade name" I-369 "). Then, ethyl acetate was added so that the total solid content was 50% by mass, and the mixture was stirred at 40 ° C. for 1 hour to obtain a curable resin composition solution.

(Example 2)
(A) It replaced with (A-1) which is a component, and except having used (A-2), operation similar to Example 1 was performed and the curable resin composition solution was obtained.

(Example 3)
(A) In place of (A-1) which is the component, (A-3) is used, and (B-2) is used in place of (B-1) which is the component (B). The same operation as in Example 1 was performed to obtain a curable resin composition solution.

Example 4
(A) It replaced with (A-1) which is a component, and except having used (A-3), operation similar to Example 1 was performed and the curable resin composition solution was obtained.

(Example 5)
(B) It replaced with (B-3) which is a component, and except having used (B-4), operation similar to Example 4 was performed and the curable resin composition solution was obtained.

(Example 6)
(B) Component (B-3) is not used, but (B-1) 5.35 g (solid content: 3.7 g) is used, except that the same operation as in Example 1 is carried out to cure. A functional resin composition solution was obtained.

(Example 7)
(B) Without using (B-1) which is a component, except having used 3.7 g of (B-3), operation similar to Example 1 was performed and the curable resin composition solution was obtained. .

(Comparative Example 1)
(A) The same operation as Example 1 was performed except having used 9.0 g of (B-1) without using a component, and the curable resin composition solution was obtained.

(Comparative Example 2)
The same operation as in Example 1 was performed except that 10 g of (A-1) was used without using the component (B) to obtain a curable resin composition solution.

(Comparative Example 3)
(A) It replaced with (A-1) which is a component, and performed the same operation as Example 1 except having used (A-4) which is an alternative (A) component, and set the curable resin composition solution. Obtained.

(Comparative Example 4)
A high heat-resistant insulating adhesive film (siloxane modified polyamideimide resin, manufactured by Hitachi Chemical Co., Ltd., trade name “KS-7003”) was prepared as a film adhesive.

  Table 1 summarizes the compounding ratios of the components of the curable resin composition solutions obtained in Examples 1 to 7 and Comparative Examples 1 to 3.

注）表１中の値は、各成分の固形分の含有量（ｇ）を示す。また、表１中の記号「−」は、該当する成分を含有していないことを示す。

Note) The values in Table 1 indicate the solid content (g) of each component. Moreover, the symbol “-” in Table 1 indicates that the corresponding component is not contained.

(Preparation of test specimen for evaluation)
The curable resin compositions of Examples 1 to 7 and Comparative Examples 1 to 3 were applied to a PET (polyethylene terephthalate) film so as to have a thickness of about 30 μm, dried at 100 ° C./15 minutes, and 10 cm long × 2 cm wide. And a PET film test piece with a curable resin composition was obtained.

  Adhere the curable resin composition side of the obtained PET film test piece with the curable resin composition on a silicon (Si) mirror wafer (thickness of 525 μm) with a urethane rubber roller on a hot plate heated to 80 ° C. The test pieces were subjected to additional heat (thermocompression bonding process) at 120 ° C./10 minutes, respectively.

  In Comparative Example 4, a PEN (polyethylene naphthalate) film was cut into a length of 10 cm × 2 cm and heated on a hot plate at 150 ° C. between the silicon mirror wafer (thickness: 525 μm) and the PEN film. In the state which pinched | interposed the 4 heat-resistant insulation adhesive film, what was adhere | attached with the urethane-type rubber roller and 180 degreeC / 30 minute additional heat (thermocompression bonding process) was used as the test piece for evaluation.

(Evaluation of adhesion and peelability)
The adhesiveness was evaluated by measuring the 180 ° peel strength at normal temperature of the test piece before irradiation with ultraviolet rays (UV) using an autograph (manufactured by Shimadzu Corporation, trade name “AGS-H 100N”). From the viewpoint of chemical resistance and water resistance, the peel strength before UV irradiation is preferably 5 N / 20 mm or more, more preferably 6.5 N / 20 mm or more, and 7.5 N / 20 mm or more. Is particularly preferred. Moreover, peelability was evaluated by measuring the peel strength after irradiating UV with the irradiation amount of 1000 mJ / cm < ² > (wavelength 365nm) from the PET film or PEN film on the produced test piece. From the viewpoint of reducing the load on the silicon mirror wafer, the peel strength after UV irradiation is preferably 2.5 N / 20 mm or less, more preferably 0.5 N / 20 mm or less, and 0.3 N / 20 mm or less. It is particularly preferred that

  Furthermore, the presence or absence of deposits or residues on the silicon mirror wafer surface after the peelability evaluation (Si surface deposits after peeling) was visually observed. On the surface of the silicon mirror wafer, A having no deposits or residues derived from the curable resin composition was designated A, and B having deposits or residues derived from the curable resin composition was designated B.

(chemical resistance)
One of the above test pieces was immersed in a 90 ° C. aqueous hydrochloric acid solution (concentration 1.0 mol / L) and another test piece in a 75 ° C. sodium hydroxide aqueous solution (concentration 1.0 mol / L) for 1 hour. . At this time, the resin composition layer having no dissolution or appearance abnormality was A, and the resin composition layer having dissolution or appearance abnormality was B.

注）表２中の記載「＞２５」は、Ｓｉ基材が破壊したため、数値は最大値を示した。また、比較例１の硬化性樹脂組成物は、フィルム形成性に劣るため、ピール強度を測定することはできなかった。また、表２中の記号「−」は、ＵＶ照射前のピール強度を測定することができなかったので、評価を行わなかったことを示す。

Note) The description “> 25” in Table 2 shows the maximum value because the Si base material was destroyed. Moreover, since the curable resin composition of the comparative example 1 was inferior to film formation, it was not possible to measure the peel strength. Further, the symbol “-” in Table 2 indicates that evaluation was not performed because the peel strength before UV irradiation could not be measured.

  When the curable resin compositions of Examples 1 to 7 were used, it was confirmed that although they had a sufficiently high peel strength before UV irradiation, the peel strength was lowered and excellent peelability after UV irradiation. Among them, the curable resin compositions prepared in Examples 3, 4 and 5 have a high peel strength before UV irradiation and a small peel strength after UV irradiation. It is particularly suitable when used for protective film applications.

  DESCRIPTION OF SYMBOLS 1 ... Wafer, 2 ... Protective layer, 3 ... Plating film, 22 ... Protective layer after actinic ray irradiation.

Claims (7)

(A) urethane resin;
(B) a photopolymerizable compound having one or more ethylenically unsaturated groups in the molecule;
(C) a photopolymerization initiator;
A curable resin composition comprising:   The curable resin composition according to claim 1, wherein the urethane resin has a polybutadiene skeleton and / or a polyisoprene skeleton.   The curable resin composition according to claim 1, wherein the urethane resin further has a polycarbonate skeleton.   The curable resin composition according to any one of claims 1 to 3, wherein the photopolymerizable compound contains a compound having three or more ethylenically unsaturated groups in the molecule.   The curable resin composition according to any one of claims 1 to 4, wherein the photopolymerizable compound contains a urethane compound having a polycarbonate skeleton.   A curable resin film comprising: a support film; and a resin composition layer formed of the curable resin composition according to any one of claims 1 to 5 formed on the support film. A protective layer forming step of forming a protective layer comprising the curable resin composition according to any one of claims 1 to 5 on one surface of an adherend;
A plating step of forming a plating film on the surface of the adherend opposite to the protective layer forming surface;
After the plating step, the protective layer is irradiated with actinic rays to be photocured, and a peeling step of peeling the protective layer after photocuring from the adherend,
A plating method comprising:

Images