JP5946665B2 - Electrode for wire bonding or Au stud bump - Google Patents

Description

  The present invention relates to an electrode for wire bonding and an electrode for Au stud bump.

As an electrical connection method between an electrode (pad) in a semiconductor element such as a transistor manufactured on a semiconductor wafer and an electrode on a mounting substrate or the like on which the semiconductor wafer is mounted, the diameter of both electrodes is made of gold or the like. A wire bonding method for connecting via thin wires (wires) of about 20 to 50 μm, and protruding electrodes (bumps) are formed on the electrodes (pads) and aligned with the electrode pads on the opposing substrate. A flip chip method is known.
Generally, wire bonding is performed by the following procedure. That is, a cylindrical capillary made of a wire is lowered, heat and ultrasonic waves are applied while pressing the lower end of the wire against one electrode, and the wire is crimped to the electrode. The wire is moved to the other electrode position, and similarly, the proximal end of the wire sent out from the capillary is crimped to the other electrode, and the wire is cut at the proximal end portion. This series of operations is performed automatically by a wire bonding apparatus.
In the flip chip type Au-based connection method, wire bonding technology is used for a flip chip having a wire (stud) of a certain length (height) on a pressure-bonded ball that is pressure-bonded on an electrode (pad). Stud bumps are formed. The formed stud bump and the conductor formed on the circuit board are connected by a flip chip bonding method.

Conventionally, the electrodes (pads) in the above semiconductor element are made of aluminum. When wire bonding is performed, wire bonding is performed directly on aluminum. However, since aluminum is weak in strength, aluminum is surrounded by the force during bonding. There was a problem that the circuit was short-circuited especially in the case of fine wiring (splash). In addition, due to the thinning of the aluminum pad thickness, the underlying element of the electrode may be damaged.
Damage can be prevented by forming a Ni film and a Pd film on the aluminum surface. However, Ni / Pd / Au is expensive because it uses Au, and Ni / Pd becomes Ni / Pd / Au. Compared with oxidation of Pd, wire bonding characteristics are inferior. Particularly after heat treatment, the characteristics deteriorated due to Pd oxidation, and wire bonding could not be performed.

  An object of the present invention is to provide an electrode for wire bonding and an electrode for Au stud bump that have high adhesion strength, excellent wire bonding property and Au stud bump bonding property, and can prevent damage to elements.

As a result of intensive studies on the above problems, the present inventors have found that the above problems can be solved by the following wire bonding electrode and Au stud bump electrode, and have reached the present invention.
That is, the present invention is as follows.
(1) An electrode for wire bonding or Au stud bump having a structure of an Ni coating on an Al electrode or a Cu electrode, a Pd coating on the Ni coating, and an organic antioxidant coating on the Pd coating .
(2) The wire bonding or Au stud as described in (1) above, having a structure of an Ni coating on the Al electrode , a Pd coating on the Ni coating, and an organic antioxidant coating on the Pd coating. Bump electrode.
(3) The wire bonding or Au stud as described in (1) above, which has a structure of a Ni coating on a Cu electrode , a Pd coating on the Ni coating, and an organic antioxidant coating on the Pd coating. Bump electrode.
( 4 ) The above-mentioned organic anti-oxidation coating is formed of an antioxidant containing an organic compound containing N, S, P or carboxylic acid as an active ingredient, according to the above (1) to ( 3 ) The electrode for wire bonding or Au stud bump in any one.
(5) on the Al electrode or Cu electrodes, by plating, said to and forming a Ni and Pd film (1) to (4) for wire bonding or Au stud bumps according to any one of Electrode manufacturing method .
(6) on the Al electrode or Cu electrodes, by an electroless plating process, said to and forming a Ni and Pd film (1) for wire bonding or Au stud according to any one of the - (4) Bump electrode manufacturing method .
(7) A semiconductor wafer comprising the wire bonding or Au stud bump electrode according to any one of (1) to ( 4 ).

According to the present invention, it is possible to provide an electrode for wire bonding and an electrode for Au stud bump that have high adhesion strength, excellent wire bondability and Au stud bump bondability, and can prevent damage to elements. Wire bonding is possible on the Pd plating film, which has been impossible in the past, and wire bonding properties such as adhesion strength are improved.
Further, when Ni is used as a base for Pd plating, particularly when the Pd film thickness is low, there is a problem that Ni corrodes, but the present invention also has an effect that a so-called organic antioxidant coating fills Pd pitting corrosion, The problem of Ni corrosion can be solved simultaneously with the problem of Pd oxidation.

  The wire bonding electrode and Au stud bump electrode of the present invention have a structure of Al electrode / Ni / Pd / organic antioxidant coating or Cu electrode / Ni / Pd / organic antioxidant coating.

The Al electrode may be an Al alloy, and examples thereof include Al, Al—Si, Al—Cu, and Al—Si—Ti.
As said Cu electrode, copper and copper alloys, such as pure copper and phosphor bronze, can be used, for example.
The Ni film and the Pd film formed on the electrode are preferably formed by plating. The Pd plating film and the Ni plating film are formed by electrolytic plating in order to plate a complex circuit with a uniform thickness. More preferably, it is formed by electroless plating. In the case of electrolytic plating, variations in the plating film occur due to the fact that a complicated circuit connection must be considered in order to pass a current and the potential difference due to the resistance of the circuit.
As the electroless Ni plating solution and the electroless Pd plating solution to be used, a known plating solution can be used.

The Ni film may be an alloy film containing Ni as a main component. Examples of the alloy containing Ni as a main component include Ni-P and Ni-B. In the case of Ni-P, the phosphorus content is preferably 2 to 13% by weight, more preferably 5 to 12% by weight. In the case of Ni-B, the boron content is preferably 1 to 5% by weight, and more preferably 2 to 4% by weight.
The thickness of the Ni film is preferably 0.5 μm or more. Although there is no particular upper limit, it is preferably 15 μm or less in consideration of forming the Ni film by electroless plating. Therefore, the thickness of the Ni film is preferably 0.5 to 15 μm, and more preferably 1 to 10 μm.
If necessary, another kind of metal film may be added between the Ni film and the Pd film.

The Pd film may be an alloy film containing Pd as a main component. Examples of alloys containing Pd as a main component include Pd—P, Pd—Ni, Pd—Co, Pd—Au, Pd—Ag, Pd-In etc. are mentioned. In the case of Pd-P, the phosphorus content is preferably 1 to 10% by weight, more preferably 2 to 6% by weight.
The thickness of the Pd film is preferably 0.005 to 0.5 μm, and more preferably 0.01 to 0.3 μm. The thinner the Pd film, the better. However, if it is less than 0.005 μm, the characteristics cannot be exhibited. The thick portion does not affect the characteristics and is not limited. However, there is a problem of cost, and 0.5 μm or less is preferable.
In the present invention, an alloy containing Ni as a main component and an alloy containing Pd as a main component mean an alloy containing Ni and Pd in the alloy by 50% by weight or more.

The organic antioxidant coating film may be any film that can prevent oxidation of Pd, and can be formed using an antioxidant.
The antioxidant is preferably formed using an antioxidant containing an organic compound containing N, S, P or carboxylic acid as an active ingredient.

（式中、Ｒ₁は水素、アルキル、置換アルキルを表わし、Ｒ₂はアルカリ金属、水素、アルキル、置換アルキルを表わす）
例えば、ベンゾトリアゾール（Ｒ₁，Ｒ₂とも水素）、１−メチルベンゾトリアゾール（Ｒ₁が水素、Ｒ₂がメチル）、トリルトリアゾール（Ｒ₁がメチル、Ｒ₂が水素）、１−（Ｎ，Ｎ−ジオクチルアミノメチル）ベンゾトリアゾール（Ｒ₁が水素、Ｒ₂がＮ，Ｎ−ジオクチルアミノメチル）などが挙げられる。 As the active ingredient of the antioxidant that forms the organic antioxidant coating, the following compounds (1) to (11) are preferably exemplified.
(1) A benzotriazole compound represented by the following general formula (1)

(Wherein R ₁ represents hydrogen, alkyl, or substituted alkyl, and R ₂ represents an alkali metal, hydrogen, alkyl, or substituted alkyl)
For example, benzotriazole (both R ₁ and R ₂ are hydrogen), 1-methylbenzotriazole (R ₁ is hydrogen, R ₂ is methyl), tolyltriazole (R ₁ is methyl, R ₂ is hydrogen), 1- (N, N-dioctylaminomethyl) benzotriazole (R ₁ is hydrogen, R ₂ is N, N-dioctylaminomethyl) and the like.

（式中、Ｒ₃はアルカリ金属又は水素を表わす）
例えば、メチルカプトベンゾチアゾール、メルカプトベンゾチアゾールのナトリウム塩、メルカプトベンゾチアゾールのカリウム塩などが挙げられる。一般式（２）においてＲ₃がアルカリ金属の場合メルカプトベンゾチアゾール系化合物の水への溶解が容易となる。 (2) Mercaptobenzothiazole compound represented by the following general formula (2)

(Wherein R ₃ represents an alkali metal or hydrogen)
For example, methylcaptobenzothiazole, mercaptobenzothiazole sodium salt, mercaptobenzothiazole potassium salt and the like can be mentioned. In the general formula (2), when R ₃ is an alkali metal, the mercaptobenzothiazole compound is easily dissolved in water.

〔式中、Ｒ₄は−ＳＨ，アルキル基かアリール基で置換されたアミノ基、又はアルキル置換イミダゾリルアルキル、Ｒ₅，Ｒ₆は−ＮＨ₂，−ＳＨ又は−ＳＭ（Ｍはアルカリ金属を表わす）を表わす〕 (3) Triazine compound represented by the following general formula (3)

[In the formula, R ₄ is —SH, an amino group substituted with an alkyl group or an aryl group, or an alkyl-substituted imidazolylalkyl; R ₅ and R ₆ are —NH ₂ , —SH or —SM (M represents an alkali metal; )

For example, the following compounds or alkali metal salts thereof such as Na or K can be mentioned. In the general formula (3), when R ₅ and R ₆ are —SM, the triazine compound is easily dissolved in water.

(4) Fatty acid R ₇ —COOH represented by the following general formula (4) (4)
(Wherein R ₇ represents a saturated and unsaturated chain hydrocarbon having 10 to 20 carbon atoms)
Preferred examples of the compound represented by the general formula (4) include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, and linoleic acid.

（式中、Ｒ₈はアルキル、置換アルキルを表わし、Ｍは水素、アルカリ金属を表わす）
一般式（５）で表わされる化合物のうち好ましいものを挙げるとラウリル酸性リン酸モノエステルなどがある。 (5) Monoalkyl phosphate represented by the following general formula (5)

(Wherein R ₈ represents alkyl or substituted alkyl, M represents hydrogen or alkali metal)
Preferable examples of the compound represented by the general formula (5) include lauryl acidic phosphoric acid monoester.

（式中、Ｒ₈はアルキル、置換アルキルを表わし、Ｍは水素、アルカリ金属を表わす）
一般式（６）で表わされる化合物のうち好ましいものを挙げると、ラウリル酸性ジリン酸エステルなどがある。 (6) Dialkyl phosphate represented by the following general formula (6)

(Wherein R ₈ represents alkyl or substituted alkyl, M represents hydrogen or alkali metal)
Preferred examples of the compound represented by the general formula (6) include lauryl acidic diphosphate.

(7) R-SH (R represents a saturated or unsaturated chain hydrocarbon having 10 to 20 carbon atoms)
Of the compounds represented by R-SH, preferred examples include lauryl mercaptan, hexadecyl mercaptan, stearyl mercaptan and the like.
(8) R—NH ₂ (R represents a saturated or unsaturated chain hydrocarbon having 10 to 20 carbon atoms)
Of the compounds represented by R—NH ₂ , preferred are laurylamine, hexadecylamine, stearylamine and the like.

(9) Tetrazole compounds Specifically,
(A-1) tetrazole, 1H-tetrazole, 1-methyltetrazole, 1-ethyltetrazole, 1-phenyltetrazole, 2-methyltetrazole, 2-ethyltetrazole, 5-methyltetrazole, 1,5-dimethyltetrazole, 1- Methyl-5-ethyltetrazole, 5-methoxytetrazole, 1-methyl-5-methoxytetrazole, 2-ethyl-5-methoxytetrazole, 5-aminotetrazole, 5-amino-2-phenyltetrazole, 2-methyl-5- Nitrotetrazole, 1-methyl-5-phenylaminotetrazole, 1-methyl-5-methylaminotetrazole, 2-phenyltetrazole, 5-phenyltetrazole, 1,5-diphenyltetrazole, 2,5-diphenyltetrazole, 1,5 − Clotrimethylenetetrazole, 1,5-cyclotetramethylenetetrazole, 1,5-cyclopentamethylenetetrazole, 5-chloromethyl-1-phenyltetrazole, 5-bromotetrazole, 1-oxytetrazole, 1,4-dioxy-5-phenyl Tetrazole, 5-oxytetrazole, 5-oxy-1-methyltetrazole, 5-oxy-2-methyltetrazole, 2-oxy-5-phenyltetrazole, 1-amino-5-phenyltetrazole, 5-amino-2-phenyl Tetrazole, 5-amino-1-methyltetrazole, 5-amino-2-methyltetrazole, 1-methyl-5-methoxytetrazole, 1-methyl-5-N, N-dimethylaminotetrazole, 1,4-dimethyl-5 -Methyliminotetrazo 1,3-dimethyl-5-iminotetrazole, 1,5-diaminotetrazole, 1-amino-5-anilinotetrazole, 5-hydrazinotetrazole, 1-amino-5-hydrazinotetrazole, 5-acetyl-1 -Phenyltetrazole, 5-tetrazolecarboxylic acid, 5-tetrazolecarboxylic acid amide, 5-cyanotetrazole, 1-phenyl-5-tetrazolecarboxylic acid, 2-ethyl-5-tetrazolecarboxylic acid, 2-phenyl-5-tetrazolecarboxylic acid Tetrazoles such as acid, 1-phenyl-5-tetrazolylacetic acid, 1-phenyl-5-tetrazolylpyruvic acid, 1-N, N-dimethylaminoethertetrazole, 5-tetrazolesulfonic acid;
(A-2) 1-methyl-5-mercaptotetrazole, 1-cyclohexyl-5-mercaptotetrazole, 1-carboxymethyl-5-mercaptotetrazole, 1-phenyl-5-mercaptotetrazole, 5-mercaptotetrazole, 5-mercapto -1-methyltetrazole, 5-mercapto-1-ethyltetrazole, 5-mercapto-1-carboxymethyltetrazole, 5-mercapto-1-cyclohexyltetrazole, 5-mercapto-1-phenyltetrazole, 5-mercapto-1- ( Mercaptotetrazoles such as hydroxyphenyl) tetrazole and 5-mercapto-1- (acetamidophenyl) tetrazole;
(A-3) tetrazolone, 1,3-dimethyl-5-tetrazolone, 1,4-dimethyl-5-tetrazolone, 2,3-diphenyltetrazolium chloride, 5-oxy-2,3-diphenyltetrazolium, 2,3 Tetrazolones such as diphenyltetrazolium hydroxide, 2,3,5-triphenyltetrazolium chloride, 5-amino-2,3-diphenyltetrazolium chloride, 5-carboxy-2,3-diphenyltetrazolium chloride, etc. And tetrazolium salts;
Among them, it is preferable to use tetrazole or mercaptotetrazole as the tetrazole-based compound.

(10) Thiadiazole compound Specifically,
(B-1) 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,3,4-thiadiazole, 1,2,3-thiadiazole-4-carboxylic acid, 1,2,3-thiadiazole- 4,5-dicarboxylic acid, 1,3,5-thiadiazole-2,5-disulfonic acid, 5,5′-dimethyl-2,2′-bis (1,3,4-thiadiazole), 2-mercapto-1 , 3,4-thiadiazole, 2-mercapto-5-methyl-1,3,4-thiadiazole, 2-mercapto-5-ethyl-1,3,4-thiadiazole, 2-mercapto-5-phenyl-1,3 , 4-thiadiazole, 5-mercapto-3-phenyl-1,2,4-thiadiazole, 2-mercapto-5-methylthio-1,3,4-thiadiazole, 2-mercaptobenzothiadiazole 2,5-dimercapto-1,3,4-thiadiazole, 3,5-dimercapto-1,2,4-thiadiazole, 5-methyl-1,2,3-thiadiazole, 5-phenyl-1,2,3 -Thiadiazole, 4,5-diphenyl-1,2,3-thiadiazole, 5-methyl-1,2,3-thiadiazole-4-carboxylic acid, 5-phenyl-1,2,3-thiadiazole-4-carboxylic acid 1,2,3-benzothiadiazole, 4-oxy-1,2,3-benzothiadiazole, 5-oxy-1,2,3-benzothiadiazole, 6-oxy-1,2,3-benzothiadiazole, 4 -Amino-1,2,3-thiadiazole, 3,5-diphenyl-1,2,4-thiadiazole, 5-Alinino-3-phenyl-1,2,4-thiadiazole, bis [5-Chloro-3- (1,2,4thiadiazolyl)] disulfide, 5-amino-1,2,4-thiadiazole, 5-imino-4-methyl-1,2,4-thiadiazoline, 2-phenyl- 1,3,4-thiadiazole, 2,5-dimethyl-1,3,4-thiadiazole, 5,5′-diphenyl-2,2′-bis (1,3,4-thiadiazole), 2-oxy-5 -Phenyl-1,3,4-thiadiazole, 3-phenyl-5-mercapto-1,3,4-thiadiazole-2-thione, 2-amino-1,3,4-thiadiazole, 2-amino-5-methyl 1,3,4-thiadiazole, 2-amino-5-phenyl-1,3,4-thiadiazole, 2-amino-5-oxy-1,3,4-thiadiazole, 2-amino-5-aminomethyl- 1,3 4-thiadiazole, 2-amino-5- (β-aminoethyl) -1,3,4-thiadiazole, 2,5-diamino-1,3,4-thiadiazole, 5-imino-2,4-diphenyl-Δ 2 -1,3,4-thiadiazoline, 2-mercapto-5-methylthio-1,3,4-thiadiazole, 2-methyl-5-mercapto-1,3,4-thiadiazole, 2-benzylmercapto-1,3 4-thiadiazole, 2-amino-5-mercapto-1,3,4-thiadiazole, 2-mercapto-4-phenyl-1,3,4-thiadiazoline-5-thione, 2-thioacetic acid-5-mercapto -1,3,4-thiadiazole, 2,5-dithioacetic acid-5-mercapto-1,3,4-thiadiazole, 2,5-dithioacetic acid Thiadiazoles such as 1,3,4-thiadiazole;
(B-2) 2-mercapto-1,3,4-thiadia-5-zolone, 2-mercapto-4-methyl-1,3,4-thiadia-5-zolone, 2-mercapto-4-phenyl-1 , 3,4-thiadia-5-zolone, 2-amino-4-mercapto-1,3,4-thiadia-5-zolone, 2-oxy-4-phenyl-1,3,4-thiadia-5-zolone , Thiadiazolones such as 2-isopropyl-4-benzyl-1,3,4-thiadia-5-zolone;
(B-3) 3,5-diphenyl-1,2,4-selenadiazole, 2,5-dimethyl-1,3,4-selenadiazole, 2,5-diphenyl-1,3,4-selena Serenadiazoles such as diazole;
Among them, it is preferable to use thiadiazoles or thiadiazolones as thiadiazole compounds.

（式（Ｉ）中、Ｘ¹〜Ｘ³及びＹ¹〜Ｙ³は各々同一もしくは異なってもよく、水素原子、又は炭素数１〜５の低級アルキル基を表す。） (11) A compound having two or more phosphonic acid groups in one molecule represented by the following formula (I), (II) or (III) and having no ester bond in the molecule and / or a salt thereof: The salt is preferably an alkali metal salt, an ammonium salt, or a salt with an amine compound.

(In formula (I), X ^{1 to} X ³ and Y ^{1 to} Y ³ may be the same or different and each represents a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms.)

（式（II）中、Ｒ¹、Ｒ²及びＲ⁴は、各々同一もしくは異なってもよく、以下の基（Ａ）を表し、Ｒ³は、以下の基（Ａ）、又は炭素数１〜５の低級アルキル基を表し、ｎは１〜３の整数を表す。

基（Ａ）中、Ｘ¹、及びＹ¹は、一般式（Ｉ）における定義と同じである。）

(In formula (II), R ¹ , R ² and R ⁴ may be the same or different and each represents the following group (A), and R ³ represents the following group (A), 5 represents a lower alkyl group, and n represents an integer of 1 to 3.

In the group (A), X ¹ and Y ¹ are the same as defined in the general formula (I). )

（式（III）中、Ｘは水素原子、又は炭素数１〜５の低級アルキル基を表し、Ｙは水素原子、炭素数１〜５の低級アルキル基、水酸基、又はアミノ基を表す。）
上記一般式（Ｉ）で表される化合物としては、ニトリロトリスメチレンホスホン酸等が工業的に入手可能なため特に好ましい。
同様に、上記一般式（II）で表される化合物としては、エチレンジアミンテトラキスメチレンホスホン酸、ジエチレントリアミンペンタキスメチレンホスホン酸等が特に好ましく、上記一般式（III）で表される化合物としては、１−ヒドロキシエタン−１，１−ジホスホン酸等が特に好ましい。

(In formula (III), X represents a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, and Y represents a hydrogen atom, a lower alkyl group having 1 to 5 carbon atoms, a hydroxyl group, or an amino group.)
As the compound represented by the general formula (I), nitrilotrismethylenephosphonic acid and the like are particularly preferable because they are industrially available.
Similarly, as the compound represented by the general formula (II), ethylenediaminetetrakismethylenephosphonic acid, diethylenetriaminepentakismethylenephosphonic acid and the like are particularly preferable. As the compound represented by the general formula (III), 1- Hydroxyethane-1,1-diphosphonic acid and the like are particularly preferable.

  The antioxidant is preferably an aqueous solution of the above compound, and the antioxidant preferably contains 0.01 g / L or more of the above compound. If the content is less than 0.01 g / L, the effect is small. On the other hand, there is no upper limit of the addition amount because the properties do not deteriorate even if the addition amount is too large. However, the addition amount is preferably 0.01 to 500 g / L, more preferably from the viewpoint of cost. 0.1 to 100 g / L.

Furthermore, by adding 0.01 to 10 g / L of a surfactant to the antioxidant, the oxidation resistance of the surface to be treated is further improved. Even if the addition amount of the surfactant is less than 0.01 g / L or more than 10 g / L, the effect of oxidation resistance cannot be obtained. The addition amount of the surfactant is preferably 0.1 to 10 g / L.
As the surfactant, one or more commercially available anionic, cationic, nonionic, and amphoteric surfactants can be appropriately selected and used.

  Anionic surfactants include sulfate ester type, sulfonate salt type, phosphate ester salt type, sulfosuccinate type, and cationic surfactants include quaternary ammonium salt type and amine salt type. Nonionic surfactants include higher alcohol ethylene oxide adducts, higher alcohol propylene oxide adducts, alkylphenol ethylene oxide adducts, polyoxyethylene polyoxypropylene block polymers, ethylenediamine polyoxyethylene polyoxypropylene block polymers, Aliphatic amine ethylene oxide adducts, aliphatic amide ethylene oxide adducts and the like, and amphoteric surfactants are preferably amino acid type, betaine type and the like.

The thickness of the organic antioxidant coating is preferably 100 mm or less. More preferably, it is 1-30cm. If the thickness exceeds 100 mm, the organic anti-oxidation coating existing between the wire and the electrode pad may cause a problem of reduced adhesion or non-adhesion of wire bonding.
The thickness of the organic coating can be measured by Auger spectroscopy.

The surface treatment using the antioxidant may be a method of forming a film on the surface of the Pd film. For example, a method of simply immersing in an antioxidant, a method of spraying an antioxidant in a shower, Or the method of apply | coating using apparatuses, such as an aired coater, a blade coater, a rod coater, a knife coater, a gravure coater, a reverse coater, a cast coater, is mentioned.
When soaking, it is sufficient to soak at room temperature for a few seconds to 1 minute. Of course, it may be heated to about 50 ° C. and soaked for a long time, but the organic coating may be formed thick and the wire bonding property may deteriorate. When Pd has already been oxidized, a pretreatment may be performed to remove the oxide film.

A wire bonding electrode having an organic anti-oxidation coating formed on the Pd plating film using the above-mentioned antioxidant can be bonded using either an Au wire or a Cu wire as a bonding wire. In addition, the adhesive strength is excellent.
As the Au bonding wire and Cu bonding wire, known general bonding wires can be used.
Moreover, it is possible to form Au stud bumps using Au wires on Au stud bump electrodes having an organic anti-oxidation coating formed on the Pd plating film using the above antioxidant, Also, the adhesive strength is excellent.

  Hereinafter, the present invention will be specifically described by way of examples.

Examples 1-13
A wafer having an Al—Si electrode pad having a size of 100 μm square is used. After zincate treatment on the electrode, nickel is applied by electroless nickel plating (KG-529 manufactured by JX Metals Corporation or KG-535 manufactured by JX Metals Corporation). A palladium film was formed to a thickness of 0.015 μm by electroless palladium plating (KG-110 manufactured by JX Metals Corporation), and the film was immersed in the following surface treatment agent for 10 seconds at room temperature as an antioxidant. As a result of measuring the film thickness of the organic film by Auger spectroscopy, it was 10 mm.
Antioxidant:
Antioxidants # 1 to # 13 were prepared by dissolving the active ingredients listed in # 1- # 13 below in pure water at a concentration of 1 g / L.
# 1 Benzotriazole # 2 2-Mercaptobenzothiazole Na salt # 3 1,3,5-Triazinethiol Na salt # 4 Oleic acid # 5 Lauryl acid phosphate monoester # 6 Lauryl acid phosphate diester # 7 Hexadecyl Mercaptan # 8 Octadecylamine # 9 1-Methyl-5-mercaptotetrazole # 10 2,5-Dimercapto-1,3,4 Thiadiazole # 11 Nitrilotrismethylenephosphonic acid # 12 Diethylenetriaminepentakismethylenephosphonic acid K salt # 13 1- Hydroxyethane-1,1-diphosphonic acid K salt

Using an Au wire GSB wire diameter of 25 μm manufactured by Tanaka Denshi Co., Ltd. for the electrode pad subjected to this oxidation treatment, bonding was performed under the conditions shown in Table 1 below using a semi-auto wire bonder HB16 (equipped with forming gas injection unit) manufactured by TPT. It was.
Bondability was evaluated based on the possibility of bonding and the strength of shear strength when bonding was possible. The shear strength was measured using a Daisy universal bond tester series 4000 at a test speed of 100 μm / s and a shear test height of 20 μm.
The results are shown in Table 2.

Example 14
Bonding was performed in the same manner as in Example 1 except that bonding was performed under the conditions described in Table 1 below using a copper wire (Maxsoft LD wire diameter φ38 μm manufactured by Heraus) instead of the Au wire GSB wire diameter 25 μm manufactured by Tanaka Denshi. The bonding property was evaluated.
The results are shown in Table 2.

Comparative Example 1
In Example 1, Ni / Pd plating was performed in the same manner, and the same treatment was performed except that the antioxidant treatment was not performed. Au wire bonding was performed in the same manner as in Example 1, but bonding was not possible.
Comparative Example 2
In Example 1, Ni / Pd plating was similarly performed, and the same treatment was performed except that the antioxidant treatment was not performed. Cu wire bonding was performed in the same manner as in Example 14, but bonding was not possible.

Comparative Example 3
In Example 1, bonding was performed in the same manner as in Example 1 except that Au wire bonding was directly performed on the Al—Si electrode pad, and the bonding property was evaluated.
The results are shown in Table 2.
Comparative Example 4
In Example 14, bonding was performed in the same manner as in Example 14 except that Cu wire bonding was directly performed on the Al—Si electrode pad, and the bonding property was evaluated.
The results are shown in Table 2.

Example 15
Using a wafer having an Al—Cu electrode pad having a size of 100 μm square, after the zincate treatment on the electrode, nickel is applied by electroless nickel plating (KG-529 made by JX Metals Corporation or KG-535 made by JX Metals Corporation). The film was formed to a thickness of 2 μm and electroless palladium plating (KG-110 manufactured by JX Metals Corporation) to form a palladium film of 0.010 μm, and immersed in the surface treatment agent # 2 as an antioxidant at room temperature for 10 seconds. As a result of measuring the film thickness of the organic film by Auger spectroscopy, it was 10 mm.
Bonding was performed in the same manner as in Example 1, and the bonding property was evaluated.
The results are shown in Table 2.

Example 16
Bonding was performed in the same manner as in Example 15 except that bonding was performed under the conditions described in Table 1 below using a copper wire (Maxsoft LD wire diameter φ38 μm manufactured by Heraus) instead of the Au wire GSB wire diameter 25 μm manufactured by Tanaka Electronics Co., Ltd. The bonding property was evaluated.
The results are shown in Table 2.

Example 17
Using a wafer having an Al electrode pad having a size of 100 μm square, after the zincate treatment on the electrode, a nickel film is formed by electroless nickel plating (KG-529 made by JX Metals Corporation or KG-535 made by JX Metals Corporation). A palladium film having a thickness of 0.020 μm was formed by electroless palladium plating (KG-110 manufactured by JX Metals Corporation) at 5 μm, and immersed in the following surface treatment agent # 1 as an antioxidant at room temperature for 10 seconds. As a result of measuring the film thickness of the organic film by Auger spectroscopy, it was 10 mm.
In the same manner as in Example 14, bonding was performed by using a copper wire (Maxsoft LD wire diameter φ38 μm manufactured by Heraus) using a semi-auto wire bonder HB16 manufactured by TPT under the conditions described in Table 1 below.
The results are shown in Table 2.

Comparative Example 5
In Example 17, Ni / Pd plating was performed in the same manner, and the same treatment was performed except that the antioxidant treatment was not performed. Cu wire bonding was performed in the same manner as in Example 17, but bonding was not possible.
Comparative Example 6
In Example 17, the same treatment as in Example 17 was performed except that the antioxidant treatment was performed on the Al electrode using the antioxidant # 1, and Cu wire bonding was performed, but bonding was not possible.

Claims (7)

An electrode for wire bonding or Au stud bump, characterized by having a structure of an Ni coating on an Al electrode or a Cu electrode, a Pd coating on the Ni coating, and an organic antioxidant coating on the Pd coating . 2. The electrode for wire bonding or Au stud bump according to claim 1 , wherein the electrode has a Ni coating on the Al electrode , a Pd coating on the Ni coating, and an organic antioxidant coating on the Pd coating . 2. The electrode for wire bonding or Au stud bump according to claim 1 , wherein the electrode has a Ni coating on the Cu electrode , a Pd coating on the Ni coating, and an organic antioxidant coating on the Pd coating . The wire according to any one of claims 1 to 3 , wherein the organic antioxidant coating is formed of an antioxidant containing an organic compound containing N, S, P or carboxylic acid as an active ingredient. Electrode for bonding or Au stud bump. The Al on the electrode or Cu electrodes, by plating, Ni and claim 1 or method of manufacturing a wire bonding or an Au stud bump electrode according to 4, characterized in that to form the Pd coating. On the Al electrode or Cu electrodes, by an electroless plating method according to claim 1-4 either wire bonding or an Au stud bump electrode, wherein the forming a Ni and Pd coating . Semiconductor wafer, characterized in that it includes a wire bonding or an Au stud bump electrode according to any one of claims 1-4.