Solder-preventing coating on metal surfaces, surface treatment solution for forming the same, and use of the solder-preventing coating

Abstract

To provide a solder spread prevention film which is excellent in compatibility with metal (especially, copper), heat resistance, and solder spread prevention property.SOLUTION: A solder spread prevention film contains an azole silane compound, wherein the azole silane compound is a compound having an azole ring and a silyl group, which can enhance interaction with metal (especially, copper). Heat resistance and solder spread prevention property are excellent by the mutual reaction of the azole silane compounds to cause dehydration condensation and siloxane bond (Si-O-Si) formation, as well as the complex formation of the azole silane compounds and metallic ions (especially, copper ions). A metallic surface formed with a solder spread prevention film containing the azole silane compounds can be expected to improve adhesion to a resin, for example, can be expected to improve adhesion between a metallic circuit of a printed wiring board and a metallic terminal of an electronic component, and a sealing resin (mold resin).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a solder-spreading prevention coating for preventing the wetting and spreading of solder on a metal surface, a surface treatment liquid for forming the same, and the use of the solder-spreading prevention coating. [Background technology]

[0002] 2. Description of the Related Art Conventionally, electronic components such as resistors, capacitors, diodes, and integrated circuits have generally been mounted on printed wiring boards by soldering.

[0003] In recent years, as the need for smaller and more powerful electronic devices has increased, the electronic components mounted on printed wiring boards have become smaller and more densely packed. As a result, the metal terminals used in electronic components have also become smaller, making it easier for solder to be absorbed into the metal terminals due to capillary action during soldering, which can cause short circuits and poor performance in electronic components.

[0004] Therefore, various methods have been proposed to prevent solder from wetting and spreading on metal surfaces to prevent solder from wicking up. For example, Patent Document 1 proposes a solder-adhesion prevention layer mainly made of polyether-modified dimethylpolysiloxane. Also, Patent Document 2 proposes a solder-wicking prevention band made of a cured acrylate-based photocurable material. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special table number 2003-510818 [Patent Document 2] Patent Publication No. 2010-161015 Summary of the Invention [Problem to be solved by the invention]

[0006] Although solder spread prevention coatings using materials such as those disclosed in Patent Documents 1 and 2 exhibit solder spread prevention properties, they do not provide solder spread prevention coatings that have sufficient affinity with metals (especially copper) and heat resistance to the heat during soldering (reflow).

[0007] The present invention has been made in view of the above problems, and an object of the present invention is to provide a solder spread prevention coating that has excellent affinity with metals (especially copper), heat resistance, and solder spread prevention properties. [Means for solving the problem]

[0008] As a result of extensive research into solving the above-mentioned problems, the present inventors have discovered that the above-mentioned problems can be solved by a solder spread prevention coating containing an azole-silane compound, and have thus completed the present invention.

[0009] That is, the present invention is as follows: [1] to [6].

[0010] [1] A solder spread prevention coating on a metal surface, characterized by containing an azole-silane compound.

[0011] [2] A surface treatment solution containing an azole-silane compound for forming the solder spread prevention coating according to claim 1 on a metal surface.

[0012] [3] A method for forming the solder spread prevention coating according to claim 1, by treating a substrate containing metal with the surface treatment liquid.

[0013] [4] A printed wiring board having the solder spread prevention coating according to claim 1 on a metal surface.

[0014] [5] An electronic component having the solder spread prevention coating according to claim 1 on a metal surface.

[0015] [6] A semiconductor wafer having the solder spread prevention coating according to claim 1 on a metal surface. [Effects of the Invention]

[0016] The solder spread prevention coating of the present invention contains an azole-silane compound, which has an azole ring and a silyl group, and therefore can enhance interaction with metals (especially copper). Furthermore, the azole-silane compounds react with each other to form siloxane bonds (Si-O-Si) through dehydration condensation, and the azole-silane compounds form complexes with metal ions (especially copper ions), resulting in excellent heat resistance and solder spread prevention.

[0017] Furthermore, a metal surface coated with a solder spread prevention coating containing an azole-silane compound is expected to have improved adhesion to resins, for example, between the metal circuits of printed wiring boards or the metal terminals of electronic components and sealing resin (mold resin). DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention will be described in detail below. However, the present invention is not limited to the embodiments described below.

[0019] (Azole silane compounds) The azole silane compound is one or more azole silane compounds selected from the group consisting of monoazole silane compounds, diazole silane compounds, triazole silane compounds, and tetrazole silane compounds. In the present invention, from the viewpoint of further improving affinity with metals (especially copper), heat resistance, solder spread prevention, and adhesion between metals and resins, the azole silane compound preferably includes one or more azole silane compounds selected from the group consisting of triazole silane compounds and tetrazole silane compounds. The azole silane compound is preferably an amino group-containing azole silane compound in which an amino group is bonded to an azole ring.

[0020] (Triazole silane compound) A triazole silane compound is a five-membered heterocyclic compound containing three nitrogen atoms (i.e., a triazole compound) that contains one silyl group-containing alkyl group (e.g., —(CH) in the general formula (Ia) described later) as a substituent in one molecule. m -Si(OR) 3-n (OH) n The silyl group-containing alkyl group may be directly bonded to an atom constituting the triazole ring, or may be bonded via a linking group (e.g., an oxygen atom, a sulfur atom, -NH-, etc.). When the silyl group-containing alkyl group is directly bonded to an atom constituting the triazole ring, the bonded atom may be a nitrogen atom or a carbon atom. From the viewpoints of further improving affinity with metals (especially copper), heat resistance, solder spread prevention, and adhesion between metals and resins, the atom to which the silyl group-containing alkyl group is bonded is preferably a nitrogen atom. The triazole ring constituting the triazole silane compound may be a 1,2,4-triazole ring or a 1,2,3-triazole ring. From the viewpoints of further improving affinity with metals (especially copper), heat resistance, solder spread prevention, and adhesion between metals and resins, the triazole ring is preferably a 1,2,4-triazole ring.

[0021] Specific examples of the triazole silane compound include triazole silane compounds represented by general formulas (Ia) and (Ib). The compounds represented by general formulas (Ia) and (Ib) may be referred to as triazole silane compound (Ia) and triazole silane compound (Ib), respectively.

[0022] [ka]

[0023] In formula (Ia), X 1 and X 2are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, a phenyl group, a benzyl group, an amino group, or an alkylthio group having 1 to 6 carbon atoms. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, and an n-dodecyl group. Specific examples of the alkylthio group include a methylthio group, an ethylthio group, an n-propylthio group, an isopropylthio group, an n-butylthio group, an isobutylthio group, a sec-butylthio group, a tert-butylthio group, an n-pentylthio group, and an n-hexylthio group. X 1 and X 2 may be the same or different, and are preferably the same. 1 and X 2 From the viewpoint of further improving affinity with metals (particularly copper), heat resistance, solder spread prevention properties, and adhesion between metals and resins, each independently preferably represents a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms (particularly a linear or branched alkyl group having 1 to 8 carbon atoms), a phenyl group, or an amino group, more preferably represents a hydrogen atom, a linear or branched alkyl group having 1 to 5 carbon atoms, or an amino group, and even more preferably represents an amino group. In formula (Ia), m represents an integer of 1 to 12. From the viewpoints of improving the solubility of the azole silane compound and further improving affinity with metals (particularly copper), heat resistance, solder spread prevention, and adhesion between metals and resins, m represents an integer of preferably 1 to 10, more preferably 1 to 5, and even more preferably 2 to 5. In formula (Ia), n represents an integer of 0 to 3. In formula (Ia), R represents a methyl group or an ethyl group, and from the viewpoint of improving the working environment, R preferably represents an ethyl group.

[0024] In formula (Ia), X 1 or X 2The triazole silane compound (Ia) in which at least one of X is an amino group is included in the above-mentioned amino group-containing azole silane compound. In this case, m, n, and R are the same as m, n, and R in formula (Ia), respectively. 1 or X 2 When one of the groups is an amino group, the other group is X in formula (Ia). 1 and X 2 may be selected from groups within the same range.

[0025] [ka]

[0026] In formula (Ib), X 1 , X 2 , m, n and R are each X in formula (Ia). 1 , X 2 , m, n and R. In formula (Ib), X 1 and X 2 From the viewpoint of further improving affinity with metals (particularly copper), heat resistance, solder spread prevention properties, and adhesion between metals and resins, each independently preferably represents a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms (particularly a linear or branched alkyl group having 1 to 8 carbon atoms), a phenyl group, or an amino group, more preferably represents a hydrogen atom, a linear or branched alkyl group having 1 to 5 carbon atoms, or an amino group, and even more preferably represents an amino group. In formula (Ib), m represents an integer of preferably 1 to 10, more preferably 1 to 5, and even more preferably 2 to 5, from the viewpoints of improving the solubility of the azole-silane compound and further improving affinity with metals (particularly copper), heat resistance, solder spread prevention, and adhesion between metals and resins. In formula (Ib), n represents an integer of 0 to 3. In formula (Ib), R represents a methyl group or an ethyl group, and from the viewpoint of improving the working environment, R preferably represents an ethyl group.

[0027] In formula (Ib), X 1 or X2 The triazole silane compound (Ib) in which at least one of X is an amino group is included in the above-mentioned amino group-containing azole silane compound. In this case, m, n, and R are the same as m, n, and R in formula (Ib), respectively. 1 or X 2 When one of the groups is an amino group, the other group is X in formula (Ib). 1 and X 2 may be selected from groups within the same range.

[0028] The triazole silane compound (Ia) includes triazole silane compounds represented by general formulas (Ia-1) to (Ia-4). The compounds represented by general formulas (Ia-1) to (Ia-4) may be referred to as triazole silane compound (Ia-1), triazole silane compound (Ia-2), triazole silane compound (Ia-3), and triazole silane compound (Ia-4), respectively.

[0029] [ka]

[0030] In formulas (Ia-1) to (Ia-4), X 1 , X 2 , m and R are each X in formula (Ia). 1 , X 2 The same applies to m and R. In the formulae (Ia-1) to (Ia-4), preferred X 1 , X 2 , m and R also represent preferred X groups in formula (Ia), respectively. 1 , X 2 , m and R.

[0031] In formulas (Ia-1) to (Ia-4), X 1 or X 2 The triazole silane compounds (Ia-1) to (Ia-4) in which at least one of X is an amino group are included in the above-mentioned amino group-containing azole silane compounds. In this case, m and R are the same as m and R in the formulas (Ia-1) to (Ia-4), respectively.1 or X 2 When one of the groups is an amino group, the other group is X in formulas (Ia-1) to (Ia-4). 1 and X 2 may be selected from groups within the same range.

[0032] The triazole silane compound (Ia-1) is a triazole silane compound (trialkoxy compound) in which n is 0 in the general formula (Ia). Similarly, the triazole silane compound (Ia-2) is a triazole silane compound when n is 1, the triazole silane compound (Ia-3) is a triazole silane compound when n is 2, and the triazole silane compound (Ia-4) is a triazole silane compound when n is 3.

[0033] Specific examples of the triazole silane compound (Ia) include the triazole silane compound (Ia-1) exemplified below, and triazole silane compounds (Ia-2) to (Ia-4) obtained by hydrolyzing (or converting) one to three alkoxy groups (e.g., methoxy groups and / or ethoxy groups) in the triazole silane compound (Ia-1) to hydroxyl groups: 1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 1-[3-(triethoxysilyl)propyl]-1,2,4-triazole, 3-methyl-1-[2-(triethoxysilyl)ethyl]-1,2,4-triazole, 5-methyl-1-[4-(trimethoxysilyl)butyl]-1,2,4-triazole, 3-ethyl-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 3-propyl-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 3-isopropyl-1-[10-(trimethoxysilyl)decyl]-1,2,4-triazole, 3-butyl-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 3-hexyl-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 5-methyl-3-octyl-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 3-dodecyl-1-[6-(triethoxysilyl)hexyl]-1,2,4-triazole, 3,5-dimethyl-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 3,5-diisopropyl-1-[3-(triethoxysilyl)propyl]-1,2,4-triazole, 3-phenyl-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 3-methyl-5-phenyl-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 3-ethyl-5-phenyl-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 3,5-diphenyl-1-[3-(triethoxysilyl)propyl]-1,2,4-triazole, 3-benzyl-1-[4-(triethoxysilyl)butyl]-1,2,4-triazole, 3-benzyl-5-phenyl-1-[3-(triethoxysilyl)propyl]-1,2,4-triazole, 3-hexylthio-1-[3-(triethoxysilyl)propyl]-1,2,4-triazole, 3-benzyl-5-propyl-1-[6-(triethoxysilyl)hexyl]-1,2,4-triazole, 3-amino-1-(triethoxysilyl)methyl-1,2,4-triazole, 3-amino-1-[2-(trimethoxysilyl)ethyl]-1,2,4-triazole, 3-amino-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 5-amino-1-[3-(triethoxysilyl)propyl]-1,2,4-triazole, 5-amino-3-ethyl-1-[6-(trimethoxysilyl)hexyl]-1,2,4-triazole, 3-amino-5-phenyl-1-[3-(triethoxysilyl)propyl]-1,2,4-triazole, 3-amino-5-benzyl-1-[3-(triethoxysilyl)propyl]-1,2,4-triazole, 3-amino-1-[6-(trimethoxysilyl)hexyl]-1,2,4-triazole, 3-amino-1-[6-(triethoxysilyl)hexyl]-1,2,4-triazole, 3-amino-1-[12-(trimethoxysilyl)dodecyl]-1,2,4-triazole, 3,5-diamino-1-(trimethoxysilyl)methyl-1,2,4-triazole, 3,5-diamino-1-(triethoxysilyl)methyl-1,2,4-triazole, 3,5-diamino-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 3,5-diamino-1-[3-(triethoxysilyl)propyl]-1,2,4-triazole, 3,5-diamino-1-[6-(trimethoxysilyl)hexyl]-1,2,4-triazole, 3,5-diamino-1-[12-(trimethoxysilyl)dodecyl]-1,2,4-triazole, 3-methylthio-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 3-isopropylthio-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 3-hexylthio-1-[10-(triethoxysilyl)decyl]-1,2,4-triazole, 3-ethylthio-5-isopropyl-1-[3-(triethoxysilyl)propyl]-1,2,4-triazole, 3,5-bis(methylthio)-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 5-hexylthio-3-methylthio-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 3-amino-5-methylthio-1-[3-(triethoxysilyl)propyl]-1,2,4-triazole, 5-amino-3-methylthio-1-[3-(trimethoxysilyl)propyl]-1,2,4-triazole, 5-amino-3-methylthio-1-[3-(triethoxysilyl)propyl]-1,2,4-triazole, 5-amino-3-isopropylthio-1-[6-(triethoxysilyl)hexyl]-1,2,4-triazole, 3-amino-5-hexylthio-1-[3-(triethoxysilyl)propyl]-1,2,4-triazole and the like.

[0034] Of the triazole silane compounds (Ia), the triazole silane compound (Ia-1) can be synthesized in accordance with WO 2018 / 186476, U.S. Patent Application Publication No. 2012 / 0021232, and WO 2019 / 058773. Specifically, as shown in the following reaction scheme (E), a triazole compound represented by general formula (Ia-x) (sometimes referred to herein as triazole compound (Ia-x)) and a halogenated alkyl silane compound represented by general formula (Ia-y) (sometimes referred to herein as halogenated alkyl silane compound (Ia-y)) are reacted in the presence of a dehydrohalogenating agent in an appropriate amount of reaction solvent at an appropriate reaction temperature and reaction time, thereby enabling synthesis in generally high yield.

[0035] [ka]

[0036] In reaction scheme (E), X 1 , X 2 , m and R are each X in formula (Ia).1 , X 2 , m and R.

[0037] Of the triazole silane compounds (Ia), the triazole silane compounds (Ia-2) to (Ia-4) can be synthesized by contacting a trialkoxy triazole silane compound (Ia-1) with an appropriate amount of water to hydrolyze it.

[0038] The triazole silane compound (Ia) may be a mixture of the triazole silane compounds (Ia-1) to (Ia-4).

[0039] The triazole silane compound (Ib) includes triazole silane compounds represented by general formulas (Ib-1) to (Ib-4). The compounds represented by general formulas (Ib-1) to (Ib-4) may be referred to as triazole silane compound (Ib-1), triazole silane compound (Ib-2), triazole silane compound (Ib-3), and triazole silane compound (Ib-4), respectively.

[0040] [ka]

[0041] In formulas (Ib-1) to (Ib-4), X 1 , X 2 , m and R are each X in formula (Ia). 1 , X 2 The same applies to m and R. In the formulae (Ib-1) to (Ib-4), preferred X 1 , X 2 , m and R are each a preferred X in formula (Ib). 1 , X 2 , m and R.

[0042] In formulas (Ib-1) to (Ib-4), X 1 or X 2The triazole silane compounds (Ib-1) to (Ib-4) in which at least one of X is an amino group are included in the above-mentioned amino group-containing azole silane compounds. In this case, m and R are the same as m and R in the formulas (Ib-1) to (Ib-4), respectively. 1 or X 2 When one of the groups is an amino group, the other group is X in formulas (Ib-1) to (Ib-4). 1 and X 2 may be selected from groups within the same range.

[0043] The triazole silane compound (Ib-1) is a triazole silane compound (trialkoxy compound) in which n is 0 in the general formula (Ib). Similarly, triazole silane compound (Ib-2) is a triazole silane compound when n is 1, triazole silane compound (Ib-3) is a triazole silane compound when n is 2, and triazole silane compound (Ib-4) is a triazole silane compound when n is 3.

[0044] Specific examples of the triazole silane compound (Ib) include the triazole silane compound (Ib-1) exemplified below, and triazole silane compounds (Ib-2) to (Ib-4) obtained by hydrolyzing (or converting) one to three alkoxy groups (e.g., methoxy groups and / or ethoxy groups) in the triazole silane compound (Ib-1) to hydroxyl groups: 1-[3-(trimethoxysilyl)propyl]-1,2,3-triazole, 1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-methyl-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-ethyl-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-propyl-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-isopropyl-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-butyl-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-hexyl-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-dodecyl-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4,5-dimethyl-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-benzyl-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-phenyl-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4,5-diphenyl-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-amino-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-methylthio-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-isopropylthio-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-hexylthio-1-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-methyl-3-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-hexyl-3-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-methylthio-3-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-amino-3-[3-(triethoxysilyl)propyl]-1,2,3-triazole, 4-propyl-1-[3-(trimethoxysilyl)propyl]-1,2,3-triazole, 4-amino-1-[3-(trimethoxysilyl)propyl]-1,2,3-triazole, 4-amino-1-[6-(triethoxysilyl)hexyl]-1,2,3-triazole, 4-amino-1-[10-(triethoxysilyl)decyl]-1,2,3-triazole, 4-Amino-1-[12-(triethoxysilyl)dodecyl]-1,2,3-triazole.

[0045] Of the triazole silane compounds (Ib), the triazole silane compound (Ib-1) can be synthesized in generally high yield by a method similar to that of the above-described reaction scheme (E), except that a triazole compound represented by general formula (Ib-x) (sometimes referred to as triazole compound (Ib-x) in this specification) is used instead of the triazole compound (Ia-x).

[0046] [ka]

[0047] In formula (Ib-x), X 1 and X 2 respectively represent X in formula (Ia). 1 and X 2 is the same as:

[0048] Of the triazole silane compounds (Ib), the triazole silane compounds (Ib-2) to (Ib-4) can be synthesized by contacting a trialkoxy triazole silane compound (Ib-1) with an appropriate amount of water to hydrolyze it.

[0049] The triazole silane compound (Ib) may be a mixture of the triazole silane compounds (Ib-1) to (Ib-4).

[0050] Examples of triazole silane compounds other than the triazole silane compound (Ia) and the triazole silane compound (Ib) include: 3-trimethoxysilylmethylthio-1,2,4-triazole, 3-[3-(trimethoxysilyl)propylthio]-1,2,4-triazole, 3-[3-(triethoxysilyl)propylthio]-1,2,4-triazole, 3-[6-(triethoxysilyl)hexylthio]-1,2,4-triazole, 3-[12-(trimethoxysilyl)dodecylthio]-1,2,4-triazole, 3-methyl-5-[2-(triethoxysilyl)ethylthio]-1,2,4-triazole, 3-methyl-5-[4-(trimethoxysilyl)butylthio]-1,2,4-triazole, 3-methyl-5-[10-(trimethoxysilyl)decylthio]-1,2,4-triazole, 3-amino-5-(triethoxysilyl)methylthio-1,2,4-triazole, 3-amino-5-[3-(trimethoxysilyl)propylthio]-1,2,4-triazole, 3-amino-5-[3-(triethoxysilyl)propylthio]-1,2,4-triazole, 3-amino-5-[6-(trimethoxysilyl)hexylthio]-1,2,4-triazole, 3-amino-5-[12-(trimethoxysilyl)dodecylthio]-1,2,4-triazole, 3-mercapto-5-[2-(trimethoxysilyl)ethylthio]-1,2,4-triazole, 3-mercapto-5-[5-(trimethoxysilyl)pentylthio]-1,2,4-triazole, 3-mercapto-5-[8-(trimethoxysilyl)octylthio]-1,2,4-triazole, 3-methylthio-5-[3-(trimethoxysilyl)propylthio]-1,2,4-triazole, 3-methylthio-5-[4-(triethoxysilyl)butylthio]-1,2,4-triazole, 3-methylthio-5-[10-(trimethoxysilyl)decylthio]-1,2,4-triazole and the like can be mentioned.

[0051] (Monoazole silane compound) The monoazole silane compound is a five-membered heterocyclic compound containing one nitrogen atom (i.e., a monoazole compound), which contains one silyl group-containing alkyl group (e.g., —(CH) in the general formula (Ia)) as a substituent in one molecule. m -Si(OR) 3-n (OH) n The atom to which the silyl group-containing alkyl group is bonded is an atom that constitutes a monoazole ring, and may be, for example, a nitrogen atom or a carbon atom. The monoazole silane compound is a compound having a substituent (for example, a group similar to the X in the general formula (Ia)). 1 and X 2 The atom to which the substituent is bonded is an atom constituting the monoazole ring, and may be, for example, a nitrogen atom or a carbon atom.

[0052] When the monoazole silane compound has an amino group as a substituent, the monoazole silane compound is included in the above-mentioned amino group-containing azole silane compound.

[0053] (Diazole silane compound) The diazole silane compound is a five-membered heterocyclic compound containing two nitrogen atoms (i.e., a diazole compound), which contains one silyl group-containing alkyl group (e.g., —(CH) in the general formula (Ia)) as a substituent in one molecule. m -Si(OR) 3-n (OH) n The atom to which the silyl group-containing alkyl group is bonded is an atom constituting a diazole ring, and may be, for example, a nitrogen atom or a carbon atom. From the viewpoint of further improving affinity with metals (particularly copper), heat resistance, solder spread prevention, and adhesion between metals and resins, the atom to which the silyl group-containing alkyl group is bonded is preferably a nitrogen atom. The diazole silane compound has a substituent (for example, a group similar to the X in the general formula (Ia)). 1 and X2 The atom to which the substituent is bonded is an atom constituting the diazole ring, and may be, for example, a nitrogen atom or a carbon atom.

[0054] When the diazole silane compound has an amino group as a substituent, the diazole silane compound is included in the above-mentioned amino group-containing azole silane compound.

[0055] (Tetrazole silane compound) A tetrazole silane compound is a five-membered heterocyclic compound containing four nitrogen atoms (i.e., a tetrazole compound) that contains one silyl group-containing alkyl group (e.g., —(CH) in the general formula (Ic) described later) as a substituent in one molecule. m -Si(OR) 3-n (OH) n The atom to which the silyl group-containing alkyl group is bonded is an atom constituting a tetrazole ring, and may be, for example, a nitrogen atom or a carbon atom. From the viewpoint of further improving affinity with metals (particularly copper), heat resistance, solder spread prevention, and adhesion between metals and resins, the atom to which the silyl group-containing alkyl group is bonded is preferably a nitrogen atom. The tetrazole silane compound has a substituent (for example, a group similar to the X in the general formula (Ia)). 1 The substituent (for example, a group similar to X in the general formula (Ia)) may further be present. 1 The atom to which the substituent (e.g., X in the general formula (Ia)) is bonded is an atom that constitutes the tetrazole ring, and may be, for example, a nitrogen atom or a carbon atom. 1 The atom to which the group (similar to the group represented by the formula (I)) is bonded is preferably a carbon atom, from the viewpoint of further improving the affinity with metals (particularly copper), heat resistance, solder spread prevention, and adhesion between metals and resins.

[0056] A specific example of the tetrazole silane compound is a tetrazole silane compound represented by general formula (Ic): The compound represented by general formula (Ic) may be referred to as the tetrazole silane compound (Ic).

[0057] [ka]

[0058] In formula (Ic), X 1 , m, n and R are each X in formula (Ia). 1 , m, n and R. In formula (Ic), X 1 From the viewpoint of further improving affinity with metals (particularly copper), heat resistance, solder spread prevention, and adhesion between metal and resin, preferably represents a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms (particularly a linear or branched alkyl group having 1 to 8 carbon atoms), a phenyl group, or an amino group, more preferably represents a phenyl group or an amino group, and even more preferably represents an amino group. In formula (Ic), m represents an integer of preferably 1 to 10, more preferably 1 to 5, and even more preferably 2 to 5, from the viewpoint of improving the solubility of the azole silane compound. In formula (Ic), n represents an integer of 0 to 3. In formula (Ic), R represents a methyl group or an ethyl group, and from the viewpoint of improving the working environment, R preferably represents an ethyl group.

[0059] In formula (Ic), the silyl group-containing alkyl group (i.e., -(CH2) m -Si(OR) 3-n (OH) n ) is bonded to the nitrogen atom at position 2, but may also be bonded to the nitrogen atom at position 1. Specifically, the tetrazole silane compound (Ic) represented by general formula (Ic) includes tetrazole silane compounds in which the silyl group-containing alkyl group is bonded to the nitrogen atom at position 1 instead of the nitrogen atom at position 2 in general formula (Ic).

[0060] In formula (Ic), X1 The tetrazole silane compound (Ic) in which m is an amino group is included in the amino group-containing azole silane compound described above, where m, n, and R are the same as m, n, and R in formula (Ic), respectively.

[0061] The tetrazole silane compound (Ic) includes tetrazole silane compounds represented by general formulas (Ic-1) to (Ic-4). The compounds represented by general formulas (Ic-1) to (Ic-4) may be referred to as tetrazole silane compound (Ic-1), tetrazole silane compound (Ic-2), tetrazole silane compound (Ic-3), and tetrazole silane compound (Ic-4), respectively. In general formulas (Ic-1) to (Ic-4), the silyl group-containing alkyl group is bonded to the nitrogen atom at the 2-position, but may also be bonded to the nitrogen atom at the 1-position, as in formula (Ic).

[0062] [ka]

[0063] In formulas (Ic-1) to (Ic-4), X 1 , m and R are each X in formula (Ia). 1 The same applies to m and R. In the formulae (Ic-1) to (Ic-4), preferred X 1 , m and R are each a preferred X in formula (Ic). 1 , m and R.

[0064] In the formulae (Ic-1) to (Ic-4), the silyl group-containing alkyl group (i.e., -(CH2) m -Si(OR) 3-n (OH) n ) is bonded to the nitrogen atom at position 2, but may also be bonded to the nitrogen atom at position 1. Specifically, the tetrazole silane compounds (Ic-1) to (Ic-4) represented by general formulas (Ic-1) to (Ic-4) respectively include tetrazole silane compounds in which the silyl group-containing alkyl group is bonded to the nitrogen atom at position 1 instead of the nitrogen atom at position 2 in general formulas (Ic-1) to (Ic-4).

[0065] In formulas (Ic-1) to (Ic-4), X 1 The tetrazole silane compounds (Ic-1) to (Ic-4) in which m is an amino group are included in the amino group-containing azole silane coupling agents described above. In this case, m and R are the same as m and R in the formulae (Ic-1) to (Ic-4), respectively.

[0066] The tetrazole silane compound (Ic-1) is a tetrazole silane compound (trialkoxy compound) in which n is 0 in the general formula (Ic). Similarly, tetrazole silane compound (Ic-2) is a tetrazole silane compound where n is 1, tetrazole silane compound (Ic-3) is a tetrazole silane compound where n is 2, and tetrazole silane compound (Ic-4) is a tetrazole silane compound where n is 3.

[0067] Specific examples of the tetrazole silane compound (Ic) include the tetrazole silane compound (Ic-1) shown below, and tetrazole silane compounds (Ic-2) to (Ic-4) obtained by hydrolyzing (or converting) one to three alkoxy groups (e.g., methoxy groups and / or ethoxy groups) in the tetrazole silane compound (Ic-1) to hydroxyl groups: 5-amino-2-[3-(trimethoxysilyl)propyl]-2H-tetrazole, 5-amino-1-[3-(trimethoxysilyl)propyl]-1H-tetrazole, 5-amino-2-[3-(triethoxysilyl)propyl]-2H-tetrazole, 5-amino-1-[3-(triethoxysilyl)propyl]-1H-tetrazole, 5-phenyl-2-[3-(trimethoxysilyl)propyl]-2H-tetrazole, 5-phenyl-1-[3-(trimethoxysilyl)propyl]-1H-tetrazole, 5-phenyl-2-[3-(triethoxysilyl)propyl]-2H-tetrazole, 5-Phenyl-1-[3-(triethoxysilyl)propyl]-1H-tetrazole.

[0068] Among the tetrazolesilane compounds (Ic), the tetrazolesilane compound (Ic-1) can be synthesized in generally high yield by a method similar to that of the above-described reaction scheme (E), except that a tetrazole compound represented by general formula (Ic-x) (sometimes referred to as the tetrazole compound (Ic-x) in this specification) is used instead of the triazole compound (Ia-x).

[0069] [ka]

[0070] In the formula (Ic-x), X 1 represents X in formula (Ia). 1 is the same as:

[0071] Among the tetrazolesilane compounds (Ic), the tetrazolesilane compounds (Ic-2) to (Ic-4) can be synthesized by contacting a trialkoxy tetrazolesilane compound (Ic-1) with an appropriate amount of water to hydrolyze it.

[0072] The tetrazole silane compound (Ic) may be a mixture of the tetrazole silane compounds (Ic-1) to (Ic-4).

[0073] In addition to the azole silane compound, a silane coupling agent having an amino group or a triazine silane compound, which is a triazine compound having a silyl group-containing alkyl group, can also be used as a component contained in the solder spread prevention coating.

[0074] (Hydrolysis and concentration of azole silane compounds) As mentioned above, azole silane compounds undergo hydrolysis when they come into contact with water. The hydrolysis process is shown in Scheme (F). Scheme (F) shows how the silyl groups in the azole silane compound are hydrolyzed, i.e., how the trialkoxysilyl group (a) gradually changes to a dialkoxyhydroxysilyl group (b), a dihydroxyalkoxysilyl group (c), and a trihydroxysilyl group (d). Note that X in the group shown in chemical formula (e) is an integer representing the number of repeating units. Specifically, some of the azole silane compounds having hydroxysilyl groups (e.g., the triazole silane compounds (Ia-2) to (Ia-4), the triazole silane compounds (Ib-2) to (Ib-4), and the tetrazole silane compounds (Ic-2) to (Ic-4)) produced in the surface treatment solution may gradually react with each other and undergo dehydration condensation in the surface treatment solution, causing the hydroxysilyl groups to form siloxane bonds (Si-O-Si) (see chemical formula (e) in scheme (F) above), converting them into silane oligomers that are poorly soluble in water. If the amount of silane oligomers produced in the surface treatment solution increases, insoluble components may precipitate, causing the surface treatment solution to become cloudy and potentially contaminating the treated product. Therefore, it is preferable that the surface treatment solution be transparent and that the amount of silane oligomers produced is suppressed.

[0075] [ka]

[0076] (Surface treatment liquid) The surface treatment solution of the present invention contains the above-mentioned azole silane compound. For example, in the triazole silane compound (Ia), the triazole silane compound (Ib), and the tetrazole silane compound (Ic), —(CH) m -Si(OR) 3-n (OH) nThe compounds represented by the formula (I) where n is an integer of 1 to 3 are species that are produced by hydrolysis of the compounds where n is 0 in the surface treatment solution. All of these are suitable as components of the surface treatment solution. Furthermore, the azole silane compounds where n is an integer of 1 to 3 can be used by extracting them from the surface treatment solution, for example, by removing volatile components from the surface treatment solution containing the azole silane compound where n is 0.

[0077] In carrying out the present invention, it is preferable to use a compound in which n is 0 as a raw material for preparing the surface treatment liquid.

[0078] The surface treatment liquid of the present invention is prepared by mixing an azole silane compound with water. The water used to prepare the surface treatment solution is preferably pure water such as ion-exchanged water or distilled water. In addition, in order to promote dissolution (formation into an aqueous solution) of the azole-silane compound, it is preferable to use a solubilizing agent in the surface treatment solution of the present invention. Examples of the solubilizing agent include acids, alkalis, and organic solvents. These solubilizing agents may be used alone or in combination of two or more. Regarding the method for preparing the surface treatment liquid when a solubilizing agent and water are used, the azole-silane compound and water may be mixed together and then the solubilizing agent may be added; the azole-silane compound may be mixed with a mixed liquid of water and the solubilizing agent; or the azole-silane compound and the solubilizing agent may be mixed together and then water may be added.

[0079] Examples of the acid include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, and organic acids such as formic acid, acetic acid, propionic acid, butyric acid, 2-ethylbutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, margaric acid, oleic acid, stearic acid, glycolic acid, lactic acid, gluconic acid, glyceric acid, malonic acid, succinic acid, levulinic acid, benzoic acid, oxalic acid, tartaric acid, malic acid, benzenesulfonic acid, tosylic acid, methanesulfonic acid, 5-sulfosalicylic acid, 4-hydroxybenzenesulfonic acid, 3-methyl-4-hydroxybenzenesulfonic acid, 4-aminobenzenesulfonic acid, camphorsulfonic acid, benzenedisulfonic acid, benzenetrisulfonic acid, sulfamic acid, and amino acids. These acids may be used alone or in combination of two or more.

[0080] Examples of the alkali include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and amines such as ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, isopropylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, allylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, monoethanolamine, diethanolamine, triethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, 2-amino-1-propanol, N,N-dimethylethanolamine, cyclohexylamine, aniline, pyrrolidine, piperidine, piperazine, pyridine, tetramethylammonium hydroxide, and tetraethylammonium hydroxide. These alkalis may be used alone or in combination of two or more.

[0081] Examples of the organic solvent include methanol, ethanol, 1-propanol, 2-propanol, butanol, tert-butyl alcohol, ethylene glycol, propylene glycol, 1,4-butanediol, glycerin, diethylene glycol, triethylene glycol, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, and diethylene glycol monomethyl ether. Examples of the organic solvent include tetrahydrofurfuryl alcohol, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol monobutyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, tetrahydrofurfuryl alcohol, furfuryl alcohol, acetone, tetrahydrofuran, dioxane, acetonitrile, 2-pyrrolidone, formamide, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, sulfolane, dimethyl carbonate, ethylene carbonate, N-methylpyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, etc. These organic solvents may be used alone or in combination of two or more.

[0082] The content of the solubilizer in the surface treatment liquid is preferably 0.1 to 99% by weight, more preferably 0.5 to 99% by weight, and even more preferably 1 to 99% by weight.

[0083] In carrying out the present invention, the concentration of the azole silane compound in the surface treatment solution, converted into the concentration of the trialkoxy azole silane compound, is preferably 0.0001 to 1.0000 mol / L, more preferably 0.0010 to 0.5000 mol / L, even more preferably 0.0050 to 0.2000 mol / L, and particularly preferably 0.0100 to 0.1000 mol / L.

[0084] The azole silane compounds having hydroxysilyl groups produced in the surface treatment solution gradually react with each other and undergo dehydration condensation, with the hydroxysilyl groups forming siloxane bonds (Si-O-Si) (see Scheme (F)), converting them into a sparingly water-soluble silane oligomer (a triazole silane compound having a group represented by chemical formula (e) in Scheme (F)). Note that X in the group represented by chemical formula (e) is an integer representing the number of repeating units.

[0085] If the amount of silane oligomers produced in the surface treatment solution increases, the insoluble components will precipitate (the treatment solution will become cloudy) and adhere to the treatment tank, the piping connected to the treatment tank, and sensors immersed in the treatment solution to detect the temperature and level of the treatment solution, which may hinder smooth surface treatment. To avoid this, it is preferable to add the aforementioned organic solvent to the surface treatment solution as a solubilizer for the silane oligomer, which is poorly soluble in water. Furthermore, it is preferable to add the aforementioned solubilizer (acid, alkali, organic solvent) to the surface treatment solution in order to promote dissolution of the azole silane compound. Since organic solvents also function as solubilizers for the silane oligomer, it is preferable to add at least one solubilizer selected from the group consisting of acids, alkalis, and organic solvents to the surface treatment solution of the present invention.

[0086] Similarly, in order to improve the stability of the surface treatment solution and the uniformity of the solder spread prevention coating (hereinafter also referred to as the chemical conversion coating), substances that generate halide ions such as chloride ions, bromide ions, and iodide ions, or metal ions such as copper ions, iron ions, and zinc ions can also be used.

[0087] Halide ions are effective in forming a uniform chemical conversion coating. Examples of substances that generate halide ions include lithium fluoride, sodium fluoride, potassium fluoride, magnesium fluoride, calcium fluoride, lithium chloride, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, lithium bromide, sodium bromide, potassium bromide, magnesium bromide, calcium bromide, lithium iodide, sodium iodide, potassium iodide, magnesium iodide, calcium iodide, ammonium fluoride, ammonium chloride, ammonium bromide, ammonium iodide, cuprous chloride, cupric chloride, cuprous bromide, and cupric bromide. Halogen compounds may be contained as impurities in other components.

[0088] The content of halide ions in the surface treatment solution is not particularly limited, and is, for example, preferably 0.10 mol / L or less (particularly 0 to 0.10 mol / L), more preferably 0.050 mol / L or less (particularly 0 to 0.050 mol / L), even more preferably 0.020 mol / L or less (particularly 0 to 0.020 mol / L), and particularly preferably 0.010 mol / L or less (particularly 0 to 0.010 mol / L).

[0089] Copper ions form complexes with azole silane compounds, which can increase the strength of the conversion coating and improve its affinity with metals (especially copper), heat resistance, solder spread prevention, and adhesion between metals and resins. The valence of the copper ions can be monovalent or divalent. Examples of substances that generate copper ions include metallic copper, copper sulfate (and its hydrates (especially the pentahydrate)), copper formate (and its hydrates (especially the tetrahydrate)), copper nitrate, cuprous chloride, cupric chloride, copper acetate (and its hydrates (especially the monohydrate)), copper hydroxide, copper oxide, copper sulfide, copper carbonate, cuprous bromide, cupric bromide, copper phosphate, and copper benzoate. The copper ions in the surface treatment liquid may also include copper ions eluted from metallic copper or copper oxide contained in the copper circuit during treatment of the copper circuit with the surface treatment liquid.

[0090] The content of copper ions in the surface treatment solution is not particularly limited, and is, for example, preferably 1.00 mol / L or less (particularly 0 mol / L or more and 1.00 mol / L or less), more preferably 0.50 mol / L or less (particularly 0 mol / L or more and 0.50 mol / L or less), even more preferably 0.10 mol / L or less (particularly 0 mol / L or more and 0.10 mol / L or less), and particularly preferably 0.010 mol / L or less (particularly 0 mol / L or more and 0.010 mol / L or less).

[0091] A known coupling agent may be used in combination as long as it does not impair the effects of the present invention. Examples of known coupling agents include silane coupling agents (silane coupling agents) having a thiol group (mercapto group), a vinyl group, an epoxy group, a (meth)acrylic group, an amino group, a chloropropyl group, or the like.

[0092] Examples of such silane coupling agents include: 3-mercaptopropyltrimethoxysilane, mercaptosilane compounds such as 3-mercaptopropylmethyldimethoxysilane; vinyltrichlorosilane, vinyltrimethoxysilane, vinylsilane compounds such as vinyltriethoxysilane; styrylsilane compounds such as p-styryltrimethoxysilane; 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, epoxysilane compounds such as 3-glycidoxypropyltriethoxysilane; acryloxysilane compounds such as 3-acryloxypropyltrimethoxysilane; 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, methacryloxysilane compounds such as 3-methacryloxypropyltriethoxysilane; N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, aminosilane compounds such as N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane; ureidosilane compounds such as 3-ureidopropyltriethoxysilane; chloropropylsilane compounds such as 3-chloropropyltrimethoxysilane; Sulfide silane compounds such as bis(triethoxysilylpropyl)tetrasulfide, and Examples include isocyanatosilane compounds such as 3-isocyanatopropyltriethoxysilane. Other examples include aluminum-based coupling agents, titanium-based coupling agents, and zirconium-based coupling agents.

[0093] The surface treatment solution of the present invention can usually be adjusted to a pH of -1.0 to 12.0. From the viewpoint of further improving solder spread prevention, the surface treatment solution of the present invention preferably has a pH of 4.0 to 11.5. Furthermore, if it is in the acidic range, it more preferably has a pH of 4.0 to 7.0, and if it is in the basic range, it more preferably has a pH of 8.0 to 11.5, and even more preferably has a pH of 8.5 to 9.5.

[0094] (Surface treatment method) When using the surface treatment solution of the present invention, the same surface treatment method as that used for conventional surface treatment solutions can be employed. Examples of this surface treatment method include a method of spraying a surface treatment liquid containing an appropriate amount of an azole-silane compound onto a metal-containing substrate, a method of applying the surface treatment liquid containing the azole-silane compound onto a metal-containing substrate with a brush or the like, a method of applying the surface treatment liquid containing the azole-silane compound onto a metal-containing substrate with a spin coater, and a method of immersing a metal-containing substrate in a surface treatment liquid containing the azole-silane compound. By these methods, a solder spread preventing coating containing an azole-silane compound can be formed on the metal surface.

[0095] Examples of the metal-containing substrate used in the present invention include granular, needle-like, fibrous, woven, plate-like, foil-like, and amorphous substrates formed from metal, as well as printed wiring boards and electronic components containing metal.

[0096] Examples of the metal include copper, aluminum, titanium, nickel, tin, iron, silver, gold, and alloys thereof. Plates, foils, plating films, circuit boards, terminals, and the like made of these metals can be used as the substrate. Specific examples of the alloy include copper alloys, which are not particularly limited as long as they contain copper, and include, for example, Cu-Ag-based, Cu-Te-based, Cu-Mg-based, Cu-Sn-based, Cu-Si-based, Cu-Mn-based, Cu-Be-Co-based, Cu-Ti-based, Cu-Ni-Si-based, Cu-Zn-Ni-based, Cu-Cr-based, Cu-Zr-based, Cu-Fe-based, Cu-Al-based, Cu-Zn-based, Cu-Co-based, and Cu-Fe-P-based alloys such as KFC. Other alloys include aluminum alloys (Al-Si alloys), nickel alloys (Ni-Cr alloys), iron alloys (Fe-Ni alloys, stainless steel, steel), and the like. Of these metals, copper and copper alloys are preferred.

[0097] By subjecting a substrate to surface treatment using the surface treatment liquid of the present invention, a chemical conversion film of the azole-silane compound is formed on the metal surface, thereby improving the solder spread prevention properties of the metal surface. In order to further enhance the effect of this treatment, the surface-treated substrate may be further subjected to a heat treatment.

[0098] The time (treatment time) for contacting the substrate with the surface treatment solution is preferably 1 second to 10 minutes, and more preferably 5 seconds to 3 minutes. If the treatment time is less than 1 second, the thickness of the chemical conversion coating formed on the substrate surface will be thin, making it difficult to obtain sufficient solder spread prevention properties. On the other hand, even if the treatment time is longer than 10 minutes, there will not be much difference in the thickness of the chemical conversion coating, so from the viewpoint of productivity, treatment for 10 minutes or less is preferred. The temperature of the surface treatment liquid when it is brought into contact with the surface of the substrate is preferably 5 to 50°C, but may be set appropriately in relation to the treatment time.

[0099] After contacting the substrate with the surface treatment liquid of the present invention, the substrate may be washed with water and then dried, or may be dried without being washed with water. Drying is preferably carried out at a temperature of from room temperature to 150°C. The water used for washing is preferably pure water such as ion-exchanged water or distilled water, but there are no particular restrictions on the method or time of washing, and it may be washed for an appropriate time by means of spraying, immersion, or the like.

[0100] The thickness of the chemical conversion coating is preferably 0.5 to 1,000 nm, more preferably 1 to 200 nm, and even more preferably 1 to 100 nm. A thickness of 0.5 nm or more sufficiently improves solder spread prevention, while a thickness of 1,000 nm or less maintains the heat resistance of the chemical conversion coating.

[0101] In the present invention, the surface of the dried chemical conversion coating may be modified by treatment with plasma, laser, ion beam, ozone, heating, humidification, etc. Alternatively, the metal surface may be cleaned using mechanical polishing such as plasma, laser, ion beam, or pumice brush, or processing methods such as drilling, in order to remove resin and ion residues from the metal surface.

[0102] Before contacting the surface of copper or a copper alloy (hereinafter, both may be referred to simply as copper) with the surface treatment liquid of the present invention, the copper surface may be subjected to at least one pretreatment selected from pickling treatment, alkali treatment, roughening treatment, heat-resistant treatment, rust-proofing treatment, and chemical conversion treatment.

[0103] The pickling treatment is carried out to remove oil and fat components adhering to the copper surface and to remove an oxide film from the copper surface, and can be carried out using solutions such as hydrochloric acid solutions, sulfuric acid solutions, nitric acid solutions, sulfuric acid-hydrogen peroxide solutions, organic acid solutions, inorganic acid-organic solvent solutions, and organic acid-organic solvent solutions.

[0104] The alkali treatment is carried out to remove oil and fat components adhering to the copper surface and to remove residues from previous processes (e.g., dry film resist for forming copper circuits). For this alkali treatment, solutions such as aqueous solutions or organic solvent-based solutions containing alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, amines such as ammonia, ethanolamine, monopropanolamine, and tetramethylammonium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, sodium acetate, potassium acetate, sodium phosphate, disodium hydrogen phosphate, potassium phosphate, and dipotassium hydrogen phosphate can be used.

[0105] The roughening treatment is performed to improve adhesion between copper and resin through the anchor effect, and creates an uneven surface on the copper surface, improving adhesion between the copper and resin material. Methods that can be used for this roughening treatment include microetching, electroplating, electroless plating, oxidation (black oxide, brown oxide), oxidation-reduction, brush polishing, and jet scrubbing.

[0106] In the microetching method, for example, etching agents based on organic acid and cupric ion, sulfuric acid and hydrogen peroxide, persulfate, copper chloride, or iron chloride can be used. In the electroplating method, minute copper particles are deposited on the copper surface to form irregularities on the copper surface.

[0107] In the heat-resistant treatment, a coating of at least one material selected from nickel, nickel-phosphorus, zinc, zinc-nickel, copper-zinc, copper-nickel, copper-nickel-cobalt, and nickel-cobalt is formed on the surface of the copper. This coating can be formed by a known electroplating method, but is not limited to electroplating, and vapor deposition or other means may also be used.

[0108] The rust prevention treatment is carried out to prevent oxidation corrosion of the copper surface, and can be carried out by forming a zinc or zinc alloy plating film or an electrolytic chromate plating film on the copper surface. Alternatively, a treatment solution containing an organic compound-based rust inhibitor such as a benzotriazole-based rust inhibitor may be brought into contact with the copper surface.

[0109] In the chemical conversion treatment, a method of forming a passivation film of tin or a method of forming a passivation film of copper oxide can be employed.

[0110] Before and / or after contacting a copper surface with the surface treatment solution of the present invention, the copper surface may be contacted with an aqueous solution containing copper ions. This aqueous solution containing copper ions has the functions of improving the film-forming properties of the chemical conversion film formed on the copper surface and making the thickness of the chemical conversion film formed on the copper surface uniform. The valence of the copper ions is not particularly limited, and they are monovalent or divalent copper ions. The copper ion source for the copper ion-containing aqueous solution is not particularly limited as long as it is a copper salt that dissolves in water, and examples thereof include copper salts such as copper sulfate, copper nitrate, copper chloride, copper formate, copper acetate, etc. Ammonia, hydrochloric acid, etc. may be added to solubilize the copper salt in water.

[0111] Before and / or after contacting a copper surface with the surface treatment solution of the present invention, the copper surface may be contacted with an acidic or alkaline aqueous solution, which, like the aqueous solution containing copper ions, also has the function of making the thickness of the chemical conversion film formed on the copper surface uniform. The acidic aqueous solution and the alkaline aqueous solution are not particularly limited, but examples of the acidic aqueous solution include aqueous solutions containing mineral acids such as sulfuric acid, nitric acid, and hydrochloric acid, and aqueous solutions containing organic acids such as formic acid, acetic acid, lactic acid, glycolic acid, and amino acids. Examples of the alkaline aqueous solution include aqueous solutions containing alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, amines such as ammonia, ethanolamine, monopropanolamine, and tetramethylammonium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, sodium acetate, potassium acetate, sodium phosphate, disodium hydrogen phosphate, potassium phosphate, and dipotassium hydrogen phosphate.

[0112] Before contacting the copper surface with the surface treatment liquid of the present invention, an aqueous solution containing a known coupling agent may be brought into contact with the copper surface.

[0113] After the surface treatment liquid of the present invention has been brought into contact with the copper surface, an aqueous solution containing a known coupling agent may be brought into contact with the copper surface.

[0114] After the surface treatment liquid of the present invention has been brought into contact with the copper surface, the copper surface may be contacted with a treatment liquid containing a known organic compound-based rust inhibitor, such as a benzotriazole-based rust inhibitor.

[0115] In the present invention, the solder spread preventing coating of the present invention or the surface treatment liquid for forming the solder spread preventing coating can be suitably used for substrates (particularly printed wiring boards and electronic components) containing metal (particularly copper or copper alloy). For example, when mounting electronic components such as resistors, capacitors, diodes, and integrated circuits on the metal wiring layer of a printed wiring board by soldering, the solder spread preventing coating is suitable for preventing solder from spreading to predetermined portions of the metal wiring layer of the printed wiring board or the metal terminals of the electronic components, and is suitable for surface treatment for forming the solder spread preventing coating, and can prevent short circuits and poor performance of the printed wiring board or electronic components during mounting by soldering.

[0116] In the case of semiconductor wafers, the present invention is suitable for use in surface treatment of semiconductor circuits to prevent solder spreading in semiconductor circuits formed on the semiconductor wafer, and to improve adhesion (tightness) between the semiconductor circuit and a protective film (e.g., insulating protective films such as photosensitive positive type, photosensitive negative type, and non-photosensitive buffer coats and bump protective films). It is also suitable for surface treatment of copper circuit rewiring layers in package substrates (WL-CSP, FO-WLP, PLP) and 2.5-dimensional (2.5D) or three-dimensional (3D) interposer substrates that form rewiring layers on semiconductor wafers, with the aim of preventing solder spreading in the copper circuit rewiring layer and improving adhesion (adhesion) between the copper circuit rewiring layer and insulating materials. Examples of the protective film and insulating material include polyimide resin, polybenzoxazole resin, and silicone resin.

[0117] The printed wiring board can be produced by contacting the surface of a copper wiring with the surface treatment solution of the present invention, followed by rinsing with water and drying, and then forming an insulating resin layer on the copper wiring. The contacting method is as described above, and immersing the copper wiring in the surface treatment solution or spraying the copper wiring with the treatment solution is preferred because it is simple and reliable. There are no particular limitations on the method of washing with water, but immersing the copper wiring in washing water or spraying the washing water onto the surface of the copper wiring is simple, reliable and preferred. The insulating resin layer can be formed by a known method, such as applying a semi-cured resin material or applying a liquid resin material containing a solvent. Next, via holes are formed to connect the upper and lower wiring. By repeating this process, a multilayer printed wiring board can be produced.

[0118] In the above-mentioned method for forming a circuit on a printed wiring board, an example of a semi-additive process using the surface treatment liquid of the present invention will be described below. (a) preparing an insulating substrate or an insulating substrate having a through-hole and a via hole, the insulating substrate having a first conductive layer on a first surface, a second surface opposite to the first surface, and inner walls of the through-hole and the via hole; (b) forming a photo-crosslinkable resin layer and a mask layer on the first surface and the second surface, and covering the first surface and the second surface and the first conductive layer on the inner walls of the through-holes and via holes with the photo-crosslinkable resin layer and the mask layer; (c) pattern-exposing the photocrosslinkable resin layer on the first and second surfaces and around the through-holes and via holes; (d) removing the mask layer from the first and second surfaces and around the through-holes and via holes; (e) developing and removing the uncured photo-crosslinkable resin layer on the first surface and the second surface and around the through-hole and the via hole using a photo-crosslinkable resin layer removal liquid to expose the first conductive layer on the first surface, the first conductive layer on the second surface, and the first conductive layer around the through-hole and the via hole; (f) forming a second conductive layer by electroplating on the first conductive layer exposed on the first surface, the second surface, and the inner walls of the through-holes and via holes; (g) removing the cured photocrosslinkable resin layer on the first surface, the second surface and around the through-hole and the via hole to expose the first and second conductive layers on the first surface, the second surface and the inner walls of the through-hole and the via hole; (h) flash etching and removing the exposed first conductive layer; (i) forming a third conductive layer on the first and second conductive layers on the first and second surfaces and on the inner walls of the through-holes and via holes by electroless plating and electrolytic plating; (j) In a method for manufacturing a circuit board, which includes at least one step of laminating an insulating resin layer on the first surface and the second surface and on the first, second, and third conductive layers on the inner walls of the through-holes and via holes, the surface treatment liquid of the present invention is brought into contact with at least one metal layer among the first, second, and third conductive layers on the first surface and the second surface and on the inner walls of the through-holes and via holes to manufacture a printed wiring board.

[0119] Furthermore, in the above-mentioned method for forming a circuit on a printed wiring board, an example of a subtractive process using the surface treatment liquid of the present invention will be described below. (a) preparing an insulating substrate or an insulating substrate having a through-hole and a via hole, the insulating substrate having a first conductive layer on a first surface, a second surface opposite to the first surface, and inner walls of the through-hole and the via hole; (b) forming a photo-crosslinkable resin layer and a mask layer on the first surface and the second surface, and covering the first surface and the second surface and the first conductive layer on the inner walls of the through-holes and via holes with the photo-crosslinkable resin layer and the mask layer; (c) pattern-exposing the photocrosslinkable resin layer on the first and second surfaces and around the through-holes and via holes; (d) removing the mask layer from the first and second surfaces and around the through-holes and via holes; (e) developing and removing the uncured photo-crosslinkable resin layer on the first surface and the second surface and around the through-hole and the via hole using a photo-crosslinkable resin layer removal liquid to expose the first conductive layer on the first surface, the first conductive layer on the second surface, and the first conductive layer around the through-hole and the via hole; (f) etching and removing the first conductive layer exposed on the first surface, the second surface, and the inner walls of the through-holes and via holes; (g) removing the cured photocrosslinkable resin layer on the first surface, the second surface and around the through-hole and the via hole to expose the first and second conductive layers on the first surface, the second surface and the inner walls of the through-hole and the via hole; (h) forming a third conductive layer on the first and second conductive layers on the first and second surfaces and on the inner walls of the through-holes and via holes by electroless plating and electrolytic plating; (i) In a method for manufacturing a circuit board, which includes at least one step of laminating an insulating resin layer on the first surface and the second surface and on the first, second, and third conductive layers on the inner walls of the through-holes and via holes, at least one metal layer of the first, second, and third conductive layers on the first surface and the second surface and on the inner walls of the through-holes and via holes is brought into contact with the surface treatment liquid of the present invention to manufacture a printed wiring board.

[0120] The copper wiring and conductive layer may be produced by any method such as electroless plating, electrolytic plating, vapor deposition, sputtering, or damascene, and may include inner via holes, through holes, connection terminals, etc.

[0121] Furthermore, "copper" in the present invention refers to foils (electrolytic copper foil, rolled copper foil, resin-coated copper foil, carrier-coated copper foil, electroless copper foil, sputtered copper foil, thin copper foil) used in electronic devices such as printed wiring boards and lead frames, decorative items, building materials, etc., plated films (electroless copper-plated film, electrolytic copper-plated film), thin films formed by vapor deposition, sputtering, damascene, etc., and particles, needles, fibers, wires, rods, tubes, plates, pillars, etc. In the case of copper wiring through which recent high-frequency electrical signals flow, it is preferable that the copper surface be smooth with an average roughness of 0.1 μm or less. The copper surface may be plated with nickel, zinc, chromium, tin, etc. as a pretreatment.

[0122] For example, in the case of use in lead frames during wire bonding mounting, the surface treatment liquid of the present invention is suitable for preventing solder spreading on metal surfaces during the lead frame production process, or on the metal frame surface after mounting a semiconductor chip (before or after the die bonding and pre-baking processes), the metal frame surface after mounting by wire bonding, or on the metal frame surface during processes up to resin sealing (before or after the resin molding and baking processes), and for surface treatment of lead frames aimed at improving the adhesiveness (tightness) between various metal surfaces and adhesives when mounting sealing resins or semiconductor chips.

[0123] Furthermore, for example, in an application example in fine wiring substrates that utilize advanced integration technology for closely arranging semiconductor chips, the surface treatment liquid of the present invention is also suitable for surface treatment of copper circuit wiring layers on 2.1-dimensional (2.1D) organic substrates or glass substrates, component-embedded substrates (EPS substrates) that incorporate semiconductors, and coreless substrates, for the purpose of preventing solder spreading in the copper circuit wiring layer and improving the adhesiveness (adhesion) between the copper circuit wiring layer and insulating materials. Furthermore, for example, the metal surface treatment liquid of the present invention is suitable for surface treatment of copper circuit wiring layers for the purposes of preventing solder spreading in the copper circuit wiring layer or copper pillars and improving the adhesion (adhesion) between the copper circuit wiring layer or copper pillars and insulating materials when pattern wiring is built in and upper and lower layers are laser via-processed and via-fill plating is performed, or when using an MIS-based embedded circuit board (ETS board) in which copper pillars formed by plating are used to establish electrical continuity between the upper and lower layers and molded resin is used for the insulating layer.

[0124] Furthermore, for example, in order to ensure electrical continuity between the upper and lower layers of a semiconductor chip, the process includes 1) pre-treatment, 2) solder bump formation, 3) solder spread prevention coating treatment, 4) fluxing, 5) chip bonding, 6) flux cleaning, 7) underfilling, and 8) molding. This process is also ideal for surface treatments aimed at preventing solder spread on metal surfaces such as copper pillars and copper circuit wiring layers, and at improving the adhesion (tightness) between the metal surface and the sealing resin (mold resin). The composition of the solder bump in the solder bump formation step is not particularly limited as long as it is Sn alone or various solder alloys, and examples of various solder alloys include binary alloys such as Sn—Sb alloys, Sn—Pb alloys, Sn—Cu alloys, Sn—Ag alloys, Sn—Bi alloys, and Sn—In alloys; and multi-component alloys in which one or more metals selected from the group consisting of Sb, Bi, In, Cu, Zn, As, Ag, Cd, Fe, Ni, Co, Au, Ge, and P are added to the above-mentioned binary alloys. Solder bumps can be formed, for example, on copper pillars or copper circuit wiring layers by solder paste application, solder balls, solder plating, or the like. The flux used in the fluxing step may be any of organic acids, amines, amine hydrohalides, organic halogen compounds, thixotropic agents, rosin, solvents, surfactants, polymer compounds, silane coupling agents, and colorants, or a combination of two or more thereof. The sealing resin (mold resin) used in the molding process may be an insulating resin with high mechanical strength such as rigidity and hardness, specifically, an insulating resin such as epoxy resin or polyimide resin, etc. Furthermore, fillers such as silica or alumina may be mixed into these resins.

[0125] The carrier-attached copper foil to be treated with the surface treatment solution of the present invention is an ultrathin electrolytic copper foil used for printed wiring boards that include a process for forming a circuit by any one of a semi-additive process, a subtractive process, a partly additive process, or a modified semi-additive process, and comprises a copper foil carrier, a release layer laminated on the copper foil carrier, and an ultrathin copper layer laminated on the release layer. The copper surface may be subjected to at least one pretreatment selected from the group consisting of pickling treatment, roughening treatment, heat-resistant treatment, rust prevention treatment, and chemical conversion treatment. [Example]

[0126] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0127] <Adjustment of surface treatment solution> The azole silane compound used was 3-amino-5-[3-(triethoxysilyl)propylthio]-1,2,4-triazole, which was synthesized according to the method described in JP 2016-125143 A. 1% by weight of the synthesized 3-amino-5-[3-(triethoxysilyl)propylthio]-1,2,4-triazole and 3% by weight of acetic acid were added to a beaker containing ion-exchanged water and stirred until uniform. Sodium hydroxide was then added until the pH reached 11, and the mixture was stirred until uniform, yielding a surface treatment solution.

[0128] <Solder spread prevention test> The prepared surface treatment solution was used to evaluate the solder spreading prevention property as described below.

[0129] [Example 1] (1) Substrate containing metal A copper clad laminate was used as the metal-containing substrate. (2) Surface treatment of substrates containing metal The metal-containing substrate was treated according to the following steps a to b. a. Roughening treatment (MEC roughening agent CZ8101 30℃ / 30 seconds), water rinse, drain b. Acid cleaning (10% sulfuric acid solution, room temperature, 30 seconds), water rinse, drain c. Immersion in surface treatment solution (30°C / 1 minute), rinse with water, drain, dry for 1 minute (100°C) (3) Check for the presence of a solder spread prevention coating The presence or absence of a solder-spreading prevention coating on the copper surface of the metal-containing substrate after surface treatment was confirmed by measuring the absorbance of the dissolved solder-spreading prevention coating using a spectrophotometer (Shimadzu Corporation UV-1800). (4) Soldering After the surface treatment, flux (WF6317 manufactured by Senju Metal Industry Co., Ltd.) was applied to the copper surface of the metal-containing substrate using a metal mask, and a solder ball (ECO SOLDER M31 manufactured by Senju Metal Industry Co., Ltd., alloy composition Sn-3.5Ag-0.75Cu, ball size φ=0.76mm) was placed on top of it and temporarily adhered, and a reflow process was performed to solder the metal-containing substrate. Reflow equipment: Koki Tech MASRN-200N2H Reflow atmosphere: Nitrogen Reflow temperature: 150-180°C / 90 seconds, then 260°C / 10 seconds Reflow times: 1 to 2 times (4) Measurement of solder wetted area For the metal-containing substrate after soldering, the area of ​​the wetted and spread portion of the metal-containing substrate when viewed from above was measured using a digital microscope (Keyence VH-6300).

[0130] [Comparative Example 1] A solder spread prevention test was carried out in the same manner as in Example 1, except that in (2) the surface treatment of the metal-containing substrate in Example 1, "c. Immersion treatment in surface treatment solution" was not carried out.

[0131] The results of the solder spread prevention test for Example 1 and Comparative Example 1 are shown in Table 1.

[0132] [Table 1]

[0133] The results in Table 1 confirm that Example 1, in which a solder spread preventing coating containing the azole-silane compound of the present invention was formed, had a smaller solder wet-spread area than Comparative Example 1, which did not have a solder spread preventing coating, and thus had excellent solder spread preventing properties. Furthermore, Example 1, in which a solder spread preventing coating containing the azole-silane compound of the present invention was formed, was formed on the copper surface of a metal-containing substrate, and it was confirmed that it had excellent affinity with metal (copper). Furthermore, Example 1, in which a solder spread preventing coating containing the azole-silane compound of the present invention was formed, maintained its excellent solder spread preventing properties even when the number of reflow cycles was increased, confirming that it had excellent heat resistance. [Industrial Applicability]

[0134] The solder spread preventive coating of the present invention has excellent affinity with metals (especially copper), heat resistance, and solder spread prevention properties, and is suitable for miniaturization of electronic components mounted on printed wiring boards and soldering in high-density mounting, and can greatly contribute to the realization of miniaturization and high performance of electronic devices, and therefore has great industrial applicability.

Claims

1. A coating for preventing solder spreading on a metal surface, comprising an azole-silane compound.

2. A surface treatment solution containing an azole-silane compound for forming the coating according to claim 1 on a metal surface.

3. A method for forming the coating according to claim 1 by treating a substrate containing a metal with the surface treatment liquid according to claim 2.

4. A printed wiring board having the coating of claim 1 on a metal surface.

5. An electronic component having the coating according to claim 1 on a metal surface.

6. A semiconductor wafer having the coating of claim 1 on a metal surface.

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