TWI848046B - A structure containing a tin layer or a tin alloy layer - Google Patents

Abstract

The structure containing a tin layer or a tin alloy layer according to the present invention includes a substrate (10), a tin layer or a tin alloy layer (12) formed on the substrate (10), and a under barrier metal (11) formed between the substrate (10) and the tin layer or tin alloy layer (12). The under barrier metal (11) is a nickel alloy layer composed of nickel and at least one of tungsten, iridium, platinum, gold, and bismuth. The under barrier metal (11) can sufficiently suppress the situation that the reaction between the metal and the tin in the tin layer or tin alloy layer (12) and forming an intermetallic compound (13) due to the metal diffusion of the metal in the substrate (10).

Description

Structure containing tin layer or tin alloy layer

The present invention relates to a structure containing a tin layer or a tin alloy layer, and more particularly to a structure containing a tin layer or a tin alloy layer provided as an electrode, a wiring or other conductive component or a bonding component of an electronic element or the like.

In the past, tin and tin alloys were used as bonding materials in electronic components due to their low melting point and excellent ductility. In this case, tin and tin alloys were mainly applied to the substrate through ball mounting process, paste process, plating process, ink-jet process, etc. As the substrate, when using copper or copper alloy substrate, nickel alloy substrate, etc., or other non-metallic substrates, a copper layer or a nickel layer is usually applied to the substrate through plating, sputtering, etc. For example, a commonly used structure is: in a flip chip bump, a nickel-plated layer of several micrometers is provided on a copper sputtering layer of a substrate, and a tin or tin-based alloy-plated layer is further provided on the nickel-plated layer. The nickel-plated layer provided on the substrate is generally called an under barrier metal (hereinafter also referred to as UBM), and one of the purposes of forming the UBM is to suppress the generation of intermetallic compounds caused by metal diffusion between copper and tin or tin-based alloys.

However, even if a nickel-plated UBM is provided, the following problem has arisen due to the miniaturization of electronic circuits in recent years: the ratio of intermetallic compounds in the joint between the copper substrate or the copper sputtered layer on the substrate and the tin layer or tin-based alloy layer increases, which deteriorates the electrical characteristics and connection reliability. In order to solve this problem, studies have been conducted to reduce the amount of intermetallic compounds generated by providing a cobalt-plated layer or a nickel-iron alloy-plated layer as a UBM under the tin layer or tin alloy layer (for example, refer to patent document 1 and non-patent document 1, etc.). Prior art literature Patent literature

Patent document 1: Specification of U.S. Patent No. 9082762. Non-patent document

Non-patent literature 1: Ja-Kyung Koo and Jae-Ho Lee, Materials Transactions, Vol. 58(2017), No. 2, pp. 148-151.

-Problem the invention is intended to solve-

By adopting the UBM disclosed in the above-mentioned Patent Document 1 and Non-Patent Document 1, a certain effect can be obtained, but under more severe conditions, it is difficult to fully suppress the formation of intermetallic compounds in the cobalt coating and the nickel-iron alloy coating, and a UBM with a more novel composition is required.

The present invention is made in view of the above-mentioned problems, and its purpose is to obtain a UBM that can further suppress the formation of intermetallic compounds between a metal-containing substrate and a tin layer or a tin alloy layer. -Solution for solving the problem-

In order to achieve the above-mentioned purpose, the inventors conducted in-depth research and found that in a structure containing a tin layer or a tin alloy layer, by using a nickel alloy layer composed of nickel and at least one of tungsten, iridium, platinum, gold and bismuth as a UBM, the formation of intermetallic compounds can be significantly suppressed, thereby completing the present invention.

Specifically, the structure containing a tin layer or a tin alloy layer described in the present invention is characterized in that it includes: a substrate, a tin layer or a tin alloy layer formed on the substrate, and a lower barrier metal formed between the substrate and the tin layer or the tin alloy layer, wherein the lower barrier metal is a nickel alloy layer composed of nickel and at least one of tungsten, iridium, platinum, gold and bismuth.

According to the structure containing a tin layer or a tin alloy layer of the present invention, a lower barrier metal is formed between the substrate and the tin layer or the tin alloy layer, and the lower barrier metal is a nickel alloy layer composed of nickel and at least one of tungsten, iridium, platinum, gold and bismuth. Therefore, the lower barrier metal can suppress the reaction of the metal with the tin in the tin layer or the tin alloy layer to form an intermetallic compound caused by the metal diffusion in the substrate. Therefore, the structure has good electrical characteristics and connection reliability, and is suitable for electronic components, etc.

As described above, the lower barrier metal is a nickel alloy layer composed of nickel and at least one of tungsten, iridium, platinum, gold and bismuth. In this case, it is preferably a nickel alloy layer composed of a nickel-tungsten alloy, a nickel-iridium alloy, a nickel-platinum alloy, a nickel-gold alloy or a nickel-bismuth alloy.

Furthermore, as described above, when the lower barrier metal is a nickel alloy layer composed of a nickel-tungsten alloy, a nickel-iridium alloy, a nickel-platinum alloy, a nickel-gold alloy or a nickel-bismuth alloy, it is preferably a nickel alloy layer containing tungsten, iridium, platinum, gold or bismuth in a mass ratio of less than 50%.

In this way, the ability of the lower barrier metal to inhibit the formation of intermetallic compounds can be further improved. -Effects of the invention-

According to the structure containing the tin layer or tin alloy layer of the present invention, the reaction between the metal and the tin in the tin layer or tin alloy layer to form an intermetallic compound caused by the metal diffusion in the substrate can be fully suppressed. Therefore, the structure has good electrical characteristics and connection reliability, and is suitable for electronic components, etc.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following description of preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, the applicable methods of the present invention, or the uses of the present invention.

1 , a structure including a tin layer or a tin alloy layer according to an embodiment of the present invention will be described.

As shown in FIG1 , the structure involved in the present embodiment has an underlayer blocking metal (UBM) 11 formed on a substrate 10, and a tin layer 12 is formed on the underlayer blocking metal 11. The substrate 10 is not particularly limited, and for example, a metal substrate made of copper, nickel, or the like, a glass substrate, a silicon substrate, a sapphire substrate, an organic material substrate, or the like can be used. However, in addition to the metal substrate, a metal film made of copper, nickel, or an alloy containing copper and nickel is sometimes formed on the upper surface of the substrate by plating or sputtering, and a protruding structure made of copper, nickel, or an alloy containing copper and nickel is further formed on the metal film. It should be noted that the metal film and the structure formed on the upper surface of such a substrate are collectively referred to as the substrate 10. In addition, the substrate 10 is not limited to a flat substrate, and may be, for example, a rod-shaped or linear strip. The tin layer 12 is formed of a single metal tin, or a tin alloy containing tin. In particular, examples of tin alloys include tin-silver, tin-silver-copper, tin-copper, tin-bismuth, or tin-indium, but are not limited thereto. The tin layer 12 may be formed, for example, by a ball implantation method, a solder paste method, a plating method, or an inkjet method, but is not limited thereto.

When the tin layer 12 is formed by electroplating, the tin plating solution used basically contains a soluble stannous salt and an acid or its salt as a liquid base, as well as various additives such as antioxidants, stabilizers, complexing agents, surfactants, brighteners, lubricants, pH adjusters, conductive salts, and preservatives as needed. In addition, as the above-mentioned soluble stannous salt, for example, stannous salts of organic sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, 2-hydroxypropylsulfonic acid (2-propanol sulfonic acid), sulfosuccinic acid (sulfosuccinic acid), and p-phenolsulfonic acid, as well as stannous fluoroborate, stannous sulfate, stannous oxide, stannous chloride, sodium stannate, potassium stannate, etc. can be used. In addition, when the tin layer 12 is composed of a tin alloy, for example, a tin alloy film can be formed using a plating solution containing a tin salt and other metal salts such as silver or copper, and an alloy film can be formed by laminating a tin plating film and other metal films such as silver or copper and then performing heat treatment to melt them.

The above-mentioned antioxidant is used to prevent the oxidation of Sn2 ⁺ in the plating bath, and examples thereof include hypophosphorous acid or its salts, ascorbic acid or its salts, hydroquinone, catechol, resorcinol, phloroglucinol, cresolsulfonic acid or its salts, phenolsulfonic acid or its salts, catecholsulfonic acid or its salts, hydroquinonesulfonic acid or its salts, hydrazine, and the like.

The stabilizer is used to stabilize the plating bath or prevent the plating bath from decomposing. For example, known stabilizers such as cyanide compounds, thioureas, thiosulfates, sulfites, sulfur-containing compounds such as acetylcysteine, and hydroxycarboxylic acids such as citric acid can be used.

The above-mentioned complexing agent is used to stabilize Sn2 ⁺ in the neutral region to prevent the formation of white precipitate or bath decomposition. For example, hydroxy carboxylic acid, polycarboxylic acid, monocarboxylic acid, etc. can be used. Specifically, gluconic acid, citric acid, glucoheptonic acid, gluconolactone, gluconolactone, formic acid, acetic acid, propionic acid, butyric acid, ascorbic acid, oxalic acid, malonic acid, succinic acid, glycolic acid, apple acid, tartaric acid, diglycolic acid, or salts thereof can be used. In particular, gluconic acid, citric acid, glucoheptonic acid, gluconolactone, gluconolactone, or salts thereof are preferred. Furthermore, ethylenediamine, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), nitrilotriacetic acid (NTA), iminodiacetic acid (IDA), iminodipropionic acid (IDP), hydroxyethylethylenediaminetriacetic acid (HEDTA), triethylenetetraaminehexaacetic acid (TTHA), ethylenedioxybis(ethylamine)-N,N,N',N'-tetraacetic acid (ethylenedioxybis(ethylamine)-N,N,N',N'-tetraacetic acid), glycines, nitrilotrimethyl phosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid, or salts thereof may also be used.

The above-mentioned surfactant helps to improve the appearance, tightness, smoothness, adhesion, etc. of the coating film, and various conventional non-ionic, anionic, amphoteric, or cationic surfactants can be used. As the above-mentioned anionic surfactant, alkyl sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkylphenyl ether sulfates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, etc. can be used. As cationic surfactants, mono-trialkylamine salts, dimethyldialkylammonium salts, trimethylalkylammonium salts, etc. can be listed. As non-ionic surfactants, compounds prepared by adding 2 to 300 mol of ethylene oxide (EO) and/or propylene oxide (PO) to C ₁ to C ₂₀ alkanols, phenols, naphthols, diphenols, C ₁ to C ₂₅ alkylphenols, aryl alkylphenols, C ₁ to C ₂₅ alkylnaphthols, C ₁ to C ₂₅ alkoxyphosphates (salts), sorbitan esters, polyalkylene glycols, C ₁ to C ₂₂ fatty amines, etc. can be used. As amphoteric surfactants, carboxybetaines, sulfobetaines, imidazolinebetaines, aminocarboxylic acids, etc. can be used.

As the brightener or semi-brightener, for example, benzaldehyde, o-chlorobenzaldehyde, 2,4,6-trichlorobenzaldehyde, m-chlorobenzaldehyde, p-nitrobenzaldehyde, p-hydroxybenzaldehyde, furfural, 1-naphthaldehyde, 2-naphthaldehyde, 2-hydroxy-1-naphthaldehyde, 3-acenaphthaldehyde, benzyl acetone, pyridylideneacetone, furfurylideneacetone, cinnamaldehyde, anisaldehyde, salicylic aldehyde, crotonaldehyde, acrolein, glutaraldehyde, paraldehyde, vanillin and other aldehydes; triazine, imidazole, indole, quinoline, 2-vinylpyridine, aniline, phenanthroline, new cuprous reagent, picolinic acid, thiourea, N-(3-hydroxybutylene)-p-sulfanilic acid, N-butylenesulfanilic acid, N-cinnamoylidenesulfanilic acid acid), 2,4-diamino-6-(2'-methylimidazolyl(1'))ethyl-1,3,5-triazine, 2,4-diamino-6-(2'-ethyl-4-methylimidazolyl(1'))ethyl-1,3,5-triazine, 2,4-diamino-6-(2'-undecylimidazolyl(1'))ethyl-1,3,5-triazine, phenyl salicylate; or benzothiazoles such as benzothiazole, 2-methylbenzothiazole, 2-hydroxybenzothiazole, 2-amino-6-methylbenzothiazole, 2-chlorobenzothiazole, 2,5-dimethylbenzothiazole, and 5-hydroxy-2-methylbenzothiazole.

As the above-mentioned lubricating agent, in addition to the above-mentioned brightening agent, the following can also be used: β-naphthol, β-naphthol-6-sulfonic acid, β-naphthalenesulfonic acid, m-chlorobenzaldehyde, p-nitrobenzaldehyde, p-hydroxybenzaldehyde, (o-, p-)methoxybenzaldehyde, vanillin, (2,4-, 2,6-)dichlorobenzaldehyde, (o-, p-)chlorobenzaldehyde, 1-naphthaldehyde, 2-naphthaldehyde, Formaldehyde, 2(4)-hydroxy-1-naphthaldehyde, 2(4)-chloro-1-naphthaldehyde, 2(3)-thiophenecarboxaldehyde, 2(3)-furfurylaldehyde, 3-indolecarboxaldehyde, salicylic aldehyde, o-phthalaldehyde, formaldehyde, acetaldehyde, paraldehyde, butyraldehyde, isobutyraldehyde, propionaldehyde, n-valeraldehyde, acrolein, crotonaldehyde, glyoxal, hydroxyl aldehyde, succinaldehyde, hexanal, isovaleraldehyde , acrolein, glutaraldehyde, 1-benzylidene-7-heptanal, 2,4-hexadienal, cinnamaldehyde, benzylcrotonaldehyde, amine aldehyde condensation, mesityl oxide, isophorone, diacetyl, 3,4-hexanedione, acetylacetone, 3-chlorobenzylideneacetone, substituted pyridylacetone, substituted furfurylideneacetone, substituted thienylmethylacetone, 4-(1-naphthyl)-3-butene-2-one, 4-(2-furyl)-3-butene-2-one, 4-(2-phenylthio)-3-butene-2-one, curcumin, benzylacetone, benzylacetone, acetophenone, (2,4-, 3,4-) dichloroacetophenone, benzylacetophenone, 2-cinnamylthiophene, 2-(ω-benzoyl)vinylfuran, vinylphenyl ketone, acrylic acid, methacrylic acid, ethylacrylic acid, ethyl acrylate, methyl methacrylate, butyl methacrylate, crotonic acid, propylene-1,3-dicarboxylic acid, cinnamic acid, (o-, m-, p-)toluidine, (o-, p-)aminoaniline, aniline, (o-, p-)chloroaniline, (2,5-, 3,4-)chloromethylaniline, N-monomethylaniline, 4,4'-diaminodiphenylmethane, N-phenyl-(α-, β-)naphthylamine, methylbenzitriazole, 1,2,3-triazine, 1,2,4-triazine, 1,3,5-triazine, 1,2,3-benzotriazine, imidazole, 2-vinylpyridine, indole, quinoline, the reaction product of monoethanolamine and o-vanillin, polyvinyl alcohol, o-catechol, hydroquinone, resorcinol, polyethyleneimine, disodium ethylenediaminetetraacetate, polyvinylpyrrolidone, etc. In addition, gelatin, polypeptone, N-(3-hydroxybutylene)-p-sulfanilic acid, N-butylenesulfanilic acid, N-cinnamylenesulfanilic acid, 2,4-diamino-6-(2'-methylimidazolyl(1'))ethyl-1,3,5-triazine, 2,4-diamino-6-(2'-ethyl-4-methylimidazolyl(1'))ethyl-1,3,5-triazine, 2,4-diamino-6-(2'-undecylimidazolyl(1'))ethyl-1,3,5-triazine, phenyl salicylate, or benzothiazoles are also effective as lubricants. As the above-mentioned benzothiazoles, benzothiazole, 2-methylbenzothiazole, 2-nitrilebenzothiazole, 2-(methylnitrile)benzothiazole, 2-aminobenzothiazole, 2-amino-6-methoxybenzothiazole, 2-methyl-5-chlorobenzothiazole, 2-hydroxybenzothiazole, 2-amino-6-methylbenzothiazole, 2-chlorobenzothiazole, 2,5-dimethylbenzothiazole, 6-nitro-2-nitrilebenzothiazole, 5-hydroxy-2-methylbenzothiazole, 2-benzothiazolethioacetic acid, etc. can be used.

As the pH adjuster, various acids such as hydrochloric acid and sulfuric acid, various bases such as ammonia water, potassium hydroxide and sodium hydroxide, etc. can be used. Furthermore, monocarboxylic acids such as formic acid, acetic acid and propionic acid, boric acids, phosphoric acids, dicarboxylic acids such as oxalic acid and succinic acid, hydroxycarboxylic acids such as lactic acid and tartaric acid can also be used.

As the conductive salt, sodium salts, potassium salts, magnesium salts, ammonium salts, amine salts, etc. of sulfuric acid, hydrochloric acid, phosphoric acid, aminosulfonic acid, sulfonic acid, etc. can be used. It should be noted that the conductive salt may be used together with the pH adjuster.

As the preservative, boric acid, 5-chloro-2-methyl-4-isothiazolin-3-one, benzalkonium chloride, phenol, phenol polyethoxylate, thymol, resorcinol, isopropylamine, phenoxyethanol, and the like can be used.

The lower barrier metal 11 is provided to suppress the metal contained in the substrate 10 from reacting with the tin in the tin layer 12 to form an intermetallic compound 13 due to metal diffusion.

The lower barrier metal 11 is a nickel alloy layer composed of nickel and at least one of tungsten, iridium, platinum, gold and bismuth. In the present embodiment, the nickel alloy layer may be a nickel alloy layer composed of nickel and tungsten, iridium, platinum, gold or bismuth, that is, a nickel-tungsten alloy, a nickel-iridium alloy, a nickel-platinum alloy, a nickel-gold alloy or a nickel-bismuth alloy, or a nickel-gold-bismuth alloy, ... A nickel alloy layer composed of nickel such as gold-platinum alloy, nickel-gold-iridium alloy, nickel-gold-tungsten alloy, nickel-platinum-iridium alloy, nickel-platinum-tungsten alloy, nickel-platinum-bismuth alloy, nickel-iridium-tungsten alloy, nickel-iridium-bismuth alloy, nickel-tungsten-bismuth alloy, and nickel-tungsten-bismuth alloy, and at least two of tungsten, iridium, platinum, gold, and bismuth. Among them, a nickel alloy layer composed of nickel-tungsten alloy, nickel-iridium alloy, nickel-platinum alloy, nickel-gold alloy, or nickel-bismuth alloy is more preferred from the viewpoint of a significant effect of suppressing the formation of the intermetallic compound 13.

When the lower barrier metal 11 is a nickel alloy layer composed of the above-mentioned nickel-tungsten alloy, nickel-iridium alloy, nickel-platinum alloy, nickel-gold alloy, or nickel-bismuth alloy, it is preferably a nickel alloy layer containing tungsten, iridium, platinum, gold, or bismuth at a mass ratio of 50% or less, more preferably 35% or less, and particularly preferably 25% or less. By using such a nickel alloy layer as the lower barrier metal 11, the effect of suppressing the generation of the intermetallic compound 13 can be further improved. It should be noted that in the nickel alloy layer composed of nickel-tungsten alloy, nickel-iridium alloy, nickel-platinum alloy, nickel-gold alloy, or nickel-bismuth alloy, the mass ratio of tungsten, iridium, platinum, gold, or bismuth is preferably 1% or more, and more preferably 3% or more. If the mass ratio of tungsten, iridium, platinum, gold, or bismuth is less than the above lower limit, the effect of suppressing the formation of the intermetallic compound 13 may not be fully exerted.

Furthermore, when the lower barrier metal 11 is a nickel alloy layer composed of the above-mentioned nickel and at least two of tungsten, iridium, platinum, gold and bismuth, it is preferably a nickel alloy layer containing at least two of tungsten, iridium, platinum, gold and bismuth in a mass ratio of less than 50%, more preferably less than 35%, particularly preferably less than 25%, and in a mass ratio of more than 1%, more preferably more than 3%.

The lower barrier metal 11 can be formed by methods such as plating, sputtering, evaporation, ball implantation, paste printing, etc. For example, when the lower barrier metal 11 is formed by electroplating, a plating solution containing an acid or its salt as a suitable base liquid in a solution in which a water-soluble nickel salt and at least one of a water-soluble tungsten salt, an iridium salt, a platinum salt, a gold salt, and a bismuth salt are dissolved, and the above-mentioned antioxidant, stabilizer, complexing agent, surfactant, brightener, slip agent, pH adjuster, conductive salt, preservative, and other additives can be used as needed.

In the structure according to the present embodiment using the lower barrier metal 11 of the above composition, although the intermetallic compound 13 is generated as shown in FIG. 1 , its thickness can be much smaller than that of the conventional structure.

The structure involved in this embodiment can be applied to electronic components such as printed circuit boards, semiconductor integrated circuits, resistors, capacitors, filters, thermistors, crystal oscillators, switches, leads or solar cells, but is not limited thereto. [Example]

Hereinafter, an embodiment of the structure including the tin layer or the tin alloy layer according to the present invention will be described in detail.

In the present embodiment, the thickness of the generated intermetallic compound is measured and compared in a structure containing a tin layer or a tin alloy layer having the above-mentioned UBM described in the present invention (Examples 1 to 12) and a structure containing a tin layer or a tin alloy layer having a conventional UBM different from the above-mentioned UBM (Comparison Examples 1 to 5).

Specifically, in Examples 1 to 12 and Comparative Examples 1 to 5, a copper plating layer is applied on the upper surface of a semiconductor wafer as a substrate, and a UBM and a tin layer or a tin alloy layer are sequentially formed on the substrate by electroplating. Electroplating was performed by a conventional known method. Depending on the type of the plated film to be formed, in Examples 1 to 12, a plating solution containing various additives in a solution containing a water-soluble nickel salt and at least one of a water-soluble tungsten salt, an iridium salt, a platinum salt, a gold salt, and a bismuth salt was used. In Comparative Examples 1 to 5, a plating solution containing various additives in a solution containing a water-soluble nickel salt, or a water-soluble nickel salt and an iron salt, or a water-soluble gold salt, or a water-soluble bismuth salt was used. The plating conditions were 50°C and 2 A/dm ² , and the film thickness of each plated film was 3 μm.

The compositions of the UBM and the tin layer or tin alloy layer formed in each embodiment and comparative example are shown in Table 1. It should be noted that the numbers in the UBM column of Table 1 represent the mass ratio, for example, "Ni 90 Au 10" represents an alloy containing 90 mass % nickel and 10 mass % gold.

The structures in Examples 1 to 12 and Comparative Examples 1 to 5 were heat treated at 180°C for 150 hours, and then the thickness of the intermetallic compound generated under the tin layer or tin alloy layer was measured. The measurement results are shown in Table 1. It should be noted that the thickness of the intermetallic compound in Examples 1 to 12 and Comparative Examples 2 to 5 is expressed as a ratio based on the result of Comparative Example 1 (100%).

Table 1 UBM Tin layer or tin alloy layer Thickness of intermetallic compound after heat treatment at 180℃ and 150 hours (%) Embodiment 1 Nickel 90 Gold 10 Tin-Silver-Copper 88.1 Embodiment 2 Nickel 95 Gold 5 Tin-Silver 67.6 Embodiment 3 Nickel 80 Bismuth 20 Tin 61.2 Embodiment 4 Nickel 95 Bismuth 5 Tin-Silver 51.8 Embodiment 5 Nickel 80 Tungsten 20 Tin-Bismuth 58.6 Embodiment 6 Nickel 90 Tungsten 10 Tin 55.7 Embodiment 7 Nickel 90 Antimony 10 Tin-Copper 62.9 Embodiment 8 Nickel 90 Platinum 10 Tin-Bismuth 66.1 Embodiment 9 Nickel 90 Gold 2 Bn 8 Tin-Silver 68.2 Embodiment 10 Nickel 80 Tungsten 10 Molybdenum 10 Tin-Silver 67.2 Embodiment 11 Nickel 75 Platinum 5 Platinum 20 Tin 69.7 Embodiment 12 Nickel 90 Tungsten 5 Gold 5 Tin 68.3 Comparison Example 1 Nickel Tin-Silver 100 Comparison Example 2 Nickel 30 Iron 70 Tin-Silver 189.1 Comparison Example 3 Nickel 42 Iron 58 Tin 126.8 Comparison Example 4 gold Tin 110.5 Comparison Example 5 Bismuth Tin-Silver 120.8

As shown in Table 1, compared with the case where a nickel layer is used as the UBM and a tin-silver alloy layer is formed thereon in the same manner as in the conventional UBM (Comparison Example 1), when a nickel-iron alloy layer is used as the UBM, the thickness of the generated intermetallic compound is greater than that in Comparison Example 1, regardless of whether a tin-silver layer is formed on the UBM (Comparison Example 2) or a tin layer is formed (Comparison Example 3).

In addition, even when a gold layer not containing nickel is used as a UBM to form a tin layer (Comparative Example 4), or a bismuth layer not containing nickel is used as a UBM to form a tin-silver layer (Comparative Example 5), the thickness of the generated intermetallic compound is still greater than that of Comparative Example 1.

On the other hand, when a nickel alloy layer composed of nickel and at least one of tungsten, iridium, platinum, gold, and bismuth is used as the UBM (Examples 1 to 12), the thickness of the generated intermetallic compound is smaller than that of Comparative Example 1 regardless of whether a tin layer or a tin alloy layer is formed. That is, it is shown that by using such a nickel alloy layer composed of nickel and at least one of tungsten, iridium, platinum, gold, and bismuth as the UBM, the generation of intermetallic compounds can be sufficiently suppressed compared with the conventional UBM. -Industrial Applicability-

According to the structure containing the tin layer or tin alloy layer of the present invention, the reaction between the metal and the tin in the tin layer or tin alloy layer to form an intermetallic compound caused by the metal diffusion in the substrate can be fully suppressed. Therefore, the structure of the present invention has good electrical characteristics and connection reliability, and is suitable for electronic components, etc.

10: Substrate 11: Underlayer barrier metal (UBM) 12: Tin layer (or Tin alloy layer) 13: Intermetallic compound

FIG. 1 is a diagram showing a structure including a tin layer or a tin alloy layer according to an embodiment of the present invention.

without.

10: Base material

11: Underlying barrier metal (UBM)

12: Tin layer (or tin alloy layer)

13: Intermetallic compounds

Claims (2)

A structure containing a tin layer or a tin alloy layer, characterized in that the structure containing a tin layer or a tin alloy layer comprises: a substrate; a tin layer or a tin alloy layer formed on the substrate; and a lower barrier metal formed between the substrate and the tin layer or the tin alloy layer; wherein the lower barrier metal comprises a nickel-tungsten alloy Gold, nickel-iridium alloy, nickel-platinum alloy, nickel-gold alloy, nickel-bismuth alloy, nickel-gold-bismuth alloy, nickel-gold-platinum alloy, nickel-gold-iridium alloy, nickel-gold-tungsten alloy, nickel-platinum-iridium alloy, nickel-platinum-tungsten alloy, nickel-platinum-bismuth alloy, nickel-iridium-tungsten alloy, nickel-platinum-bismuth alloy, nickel-iridium-tungsten alloy, nickel-iridium-bismuth alloy or nickel alloy of nickel-tungsten-bismuth alloy layer; and in the case where the lower barrier metal is a nickel alloy layer comprising a nickel-tungsten alloy, a nickel-iridium alloy, a nickel-platinum alloy, a nickel-gold alloy or a nickel-bismuth alloy, the nickel alloy layer contains tungsten, iridium, platinum, gold or bismuth at a mass ratio of 50% or less; or in the case where the lower barrier metal is a nickel-gold-bismuth alloy, a nickel-gold-platinum alloy, a nickel-gold-platinum alloy or a nickel-bismuth alloy In the case of a nickel alloy layer of a nickel-gold-iridium alloy, a nickel-gold-tungsten alloy, a nickel-platinum-iridium alloy, a nickel-platinum-tungsten alloy, a nickel-platinum-bismuth alloy, a nickel-iridium-tungsten alloy, a nickel-iridium-bismuth alloy or a nickel-tungsten-bismuth alloy, the nickel alloy layer contains two of tungsten, iridium, platinum, gold and bismuth in a mass ratio of 50% or less. A structure containing a tin layer or a tin alloy layer as described in claim 1, wherein, when the lower barrier metal is a nickel alloy layer comprising a nickel-tungsten alloy, a nickel-iridium alloy, a nickel-platinum alloy, a nickel-gold alloy, or a nickel-bismuth alloy, the nickel alloy layer contains tungsten, iridium, platinum, gold, or bismuth in a mass ratio of 1% or more; or when the lower barrier metal is a nickel alloy layer comprising nickel In the case of a nickel alloy layer of tungsten-gold-bismuth alloy, nickel-gold-platinum alloy, nickel-gold-iridium alloy, nickel-gold-tungsten alloy, nickel-platinum-iridium alloy, nickel-platinum-tungsten alloy, nickel-platinum-bismuth alloy, nickel-iridium-tungsten alloy, nickel iridium-bismuth alloy or nickel-tungsten-bismuth alloy, the nickel alloy layer contains two of tungsten, iridium, platinum, gold and bismuth in a mass ratio of 1% or more.

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