KR20180009308A - Indium electroplating compositions containing 2-imidazolidinethione compounds and methods for electroplating indium - Google Patents

Abstract

Indium electroplating compositions containing 2-imidazolidinethione compounds electroplate substantially defect-free uniform layers which have a smooth surface morphology on metal layers. The indium electroplating compositions can be used to electroplate indium metal on metal layers of various substrates such as semiconductor wafers and thermal interface materials.

Description

TECHNICAL FIELD The present invention relates to an indium electroplating composition containing a 2-imidazolidinedione compound and an electroplating method of indium. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to an indium electroplating composition containing a 2-imidazolidinedione compound, and a method of electroplating an indium metal on a metal layer. More particularly, the invention relates to an indium electroplating composition containing a 2-imidazolidinedione compound, and a method of electroplating an indium metal on a metal layer, wherein the indium metal deposit is uniform, substantially It has no void and has a smooth surface shape.

The ability to reproducibly plating uniform indium without voids having a target thickness and smooth surface morphology on the metal layer is challenging. Indium reduction occurs at potentials that are more negative than proton reduction, and the generation of significant hydrogen bubbles at the cathode increases surface roughness. The indium (1 ⁺ ) ion, which is stable due to the inert pair effect, and formed in the indium deposition process, catalyzes the proton reduction and is involved in the disproportionation reaction to produce indium ( ³⁺ ) ions. In the absence of complexing agent, the indium ions begin to precipitate out of the solution with a pH> 3. Plating indium on metals such as nickel, tin, copper and gold is a good catalyst for the proton reduction and because it is more precious than indium and can lead to corrosion of indium in galvanic interactions, to be. Indium can also form undesired intermetallic compounds with these metals. Finally, indium chemistry and electrochemistry have not been fully studied, and therefore interaction with compounds that can act as additives is not known.

In general, conventional indium electroplating baths have not been capable of electroplating indium deposits that are compatible with a number of under bump metals (UBM) such as nickel, copper, gold and tin. More importantly, conventional indium electroplating baths have not been able to electroplate indium with high coplanarity and high surface planarity on substrates containing nickel. However, indium is a highly desirable metal in many industries due to its unique physical properties. For example, it is soft enough to be easily deformed and to fill the microstructure between the two mating parts and has a low melting temperature (156 캜) and high thermal conductivity (~ 82 W / m KK) Electrical conductivity, and the ability to form and alloy intermetallic compounds with other metals in the stack. It can be used as a low temperature solder bump material in a process desired in a 3D stack assembly to reduce the damage of the assembled chip by thermal stress induced during reflow processing. Such characteristics enable various uses of indium in electronic devices and related industries including semiconductor and polycrystalline thin film solar cells.

Indium can also be used as a thermal interface material (TIM). The TIM is important for protecting electronic devices such as integrated circuits (ICs) and active semiconductor devices, e.g., microprocessors, from exceeding their operating temperature limits. It enables the bonding of heat generating devices (e.g., silicon semiconductors) to a heat sink or heat spreader (e.g., copper and aluminum parts) without creating excessive thermal barriers . The TIM can also be used in assemblies of other components of a heat sink or heat spreader stack that make up the entire thermal impedance path.

Several classes of materials are used as TIMs, such as thermal grease, thermal gel, adhesives, elastomers, thermal pads, and phase change materials. Although the above-mentioned TIM is suitable for many semiconductor devices, such TIM is inadequate due to the increased performance of semiconductor devices. Many current TIM thermal conductivities do not exceed 5 W / m ° K, and many are below 1 W / m ° K. However, there is now a need for a TIM that forms a thermal interface with an effective thermal conductivity in excess of 15 W / m [Omega] K.

Thus, indium is a highly desirable metal for electronic devices, and there is a need for an improved indium composition for electroplating indium metal on metal substrates.

The composition comprises at least one indium ion source, at least one 2-imidazolidinedione compound and citric acid, a salt thereof or a mixture thereof.

The method includes providing a substrate comprising a metal layer; Contacting the substrate with an indium electroplating composition comprising at least one indium ion source, at least one 2-imidazolidinedione compound, citric acid, a salt thereof, or a mixture thereof; And electroplating the indium metal layer onto the metal layer of the substrate using an indium electroplating composition.

The indium electroplating composition can provide a deposit of indium metal on the metal layer, which is substantially free of voids and has a uniform, smooth shape. The ability to reproducibly plating uniform indium without voids with target thickness and smooth surface morphology can extend the use of indium in the electronics industry, including semiconductor and polycrystalline thin film solar cells. Indium deposited from the electroplating compositions of the present invention can be used as a low temperature solder material desired in 3D stack assemblies to reduce the damage of assembled chips due to thermal stress induced during the reflow process. Indium can also be used as a thermal interface material to protect electronic devices such as microprocessors and integrated circuits. The present invention addresses a number of conventional problems that can not electroplate an indium layer with properties sufficient to meet the requirements for applications in advanced electronic devices.

Figure 1a is an optical microscope image of a nickel plated via having a diameter of 75 [mu] m.
Figure Ib is an optical microscope image of an indium layer on a nickel plated via with a diameter of 75 [mu] m.
Figure 2 shows an indium layer on a nickel plated via with a diameter of 75 [mu] m, from which an indium electroplated from an indium composition containing 0.25 g / L 1- (2-hydroxyethyl) -2-imidazolidinedione Is an optical microscope image of.
Figure 3 is a graphical representation of an indium composition containing 1.25 g / L of 1- (2-hydroxyethyl) -2-imidazolidinethione, indium electroplated indium on nickel plated rectangular vias It is an optical microscope image of the layer.
Figure 4 is a graph showing the results of an indium composition of indium on a nickel plated via with a diameter of 75 mu m from an indium composition containing 0.01 g / L of 1- (2-hydroxyethyl) -2-imidazolidinedione Is an optical microscope image of.
Figure 5 is a graph showing the results of an indium layer deposited on an indium electroplated indium layer on a nickel plated via having a diameter of 75 [mu] m from an indium composition containing 0.1 g / L of 1- (2-hydroxyethyl) -2- imidazolidine thione Is an optical microscope image of.
Figure 6 is an optical microscope image of an indium layer on a nickel plated via with a diameter of 75 [mu] m, indium electroplated from an indium composition containing 1- (2-hydroxyethyl) -2-imidazolidinethione and sodium chloride Image.

As used throughout the specification, the following abbreviations have the following meanings, unless the context clearly dictates otherwise: C = Celsius temperature; ˚K = Kelvin temperature; g = gram; mg = milligram; L = liters; A = ampere; dm = decimeter; ASD = A / dm ² = current density; micrometer = micrometer; ppm = million fractions; ppb = billion fraction; ppm = mg / L; Indium ion = In ^{3 +} ; Li ⁺ = lithium ion; Na ⁺ = sodium ion; K ⁺ = potassium ion; NH ₄ ⁺ = ammonium ion; nm = nanometer = 10 ^-9 meters; micrometer = 10 ^-6 meters; M = molar; MEMS = micro-electro-mechanical system; TIM = thermal interface material; IC = integrated circuit; EO = ethylene oxide and PO = propylene oxide.

The terms "depositing "," plating "and" electroplating "are used interchangeably throughout the specification. The term "copolymer" is a compound composed of two or more different monomers (mer). The term "dendrite" refers to a branched spike-like metal crystal. Unless otherwise indicated, all plating baths are aqueous solvent based, i.e., water based plating baths. All amounts are percent by weight unless otherwise indicated, and all ratios are molar basis. All numerical ranges are inclusive and arbitrary in order, except where it is appropriate that such numerical ranges are limited to a maximum of 100%.

The composition comprises at least one indium ion source that is soluble in an aqueous environment. The indium composition is free of alloy metal. Such sources include, but are not limited to, alkanesulfonic acids and aromatic sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, butanesulfonic acid, benzenesulfonic acid and indium salts of toluenesulfonic acid, indium salts of sulfamic acid, indium Sulfates, sulfates, sulphate salts, chloride and bromide salts of indium, nitrate salts, hydroxide salts, indium oxides, fluoroborate salts, carboxylic acids such as citric acid, acetoacetic acid, glyoxylic acid, pyruvic acid, glycolic acid, malonic acid, Such as arginine, aspartic acid, asparagine, glutamic acid, glycine, glutamine, leucine, lysine, threonine, isoleucine, lysine, lysine, And indoline salts of valine. Typically, the indium ion source is at least one indium salt of sulfuric acid, sulfamic acid, alkanesulfonic acid, aromatic sulfonic acid and carboxylic acid. More typically, the indium ion source is at least one indium salt of sulfuric acid and sulfamic acid.

The water soluble indium salt is included in the composition in an amount sufficient to provide an indium deposit of the desired thickness. Preferably a water-soluble indium salts are indium (3 ⁺⁾ ions to 2 g / L to 70 g / L, more preferably from 2 g / L to 60 g / L, most preferably from 2 g / L to on the composition 30 g / L. ≪ / RTI >

One or more 2-imidazolidinedione compounds are included in the indium composition. The at least one 2-imidazolidinedione compound is used in an amount of from 0.005 g / l to 5 g / l, preferably from 0.01 g / l to 3 g / l, more preferably from 0.01 g / l to 1.5 g / l In the indium composition.

The 2-imidazolidinedione compounds include, but are not limited to, compounds having the formula:

Wherein R ₁ and R ₂ are independently selected from the group consisting of hydrogen, linear or branched (C ₁ -C ₁₂ ) alkyl, linear or branched hydroxy (C ₁ -C ₁₂ ) alkyl, linear or branched (C ₁ -C ₁₂ ) alkoxy, linear or branched (C ₃ -C ₁₂₎ allyl, amino, primary, secondary, or tertiary amino (C ₁ -C ₁₂₎ alkyl, acetyl, and substituted or unsubstituted aryl (C ₁ -C ₁₂ ) Alkyl; < / RTI > R _3, R _4, R ₅ and R ₆ is hydrogen, linear or branched (C ₁ -C ₁₂₎ alkyl, hydroxyl, linear or branched, hydroxy (C ₁ -C ₁₂₎ alkyl, primary, secondary, , Or tertiary amino, aryl, linear or branched (C ₁ -C ₁₂ ) alkoxy, primary, secondary, or tertiary amino (C ₁ -C ₁₂ ) alkyl and acetyl. Substituents on the aryl group include, but are not limited to, linear or branched (C ₁ -C ₅ ) alkyl, hydroxyl, hydroxy (C ₁ -C ₅ ) alkyl, (C ₁ -C ₃ ) alkoxy, (C ₁ -C ₅ ) alkyl. Substituents replacing the hydrogen of the secondary and tertiary amino groups include, but are not limited to, linear or branched (C ₁ -C ₅ ) alkyl, substituted or unsubstituted phenyl, linear or branched hydroxyl (C ₁ -C ₅ ) alkyl and a (C ₄ -C ₈₎ alicyclic.

Preferably R ₁ and R ₂ are selected from the group consisting of hydrogen, linear or branched (C ₁ -C ₅ ) alkyl, linear or branched hydroxy (C ₁ -C ₅ ) alkyl, (C ₁ -C ₃ ) alkoxy, Primary or secondary amino (C ₁ -C ₅ ) alkyl and acetyl. Preferably, R ₃ , R ₄ , R ₅ and R ₆ are selected from hydrogen, linear or branched (C ₁ -C ₅ ) alkyl, hydroxyl, linear or branched hydroxy (C ₁ -C ₅ ) Lt; / RTI > unsubstituted phenyl. More preferably R ₁ and R ₂ are independently selected from hydrogen, (C ₁ -C ₂ ) alkyl, hydroxy (C ₁ -C ₃ ) alkyl, primary amino (C ₁ -C ₃ ) alkyl and acetyl . More preferably R ₃ , R ₄ , R ₅ and R ₆ are independently selected from hydrogen, (C ₁ -C ₄ ) alkyl, hydroxyl and phenyl.

 Examples of such 2-imidazolidinedione compounds are 2-imidazolidinedione, 1,3-dimethyl-2-imidazolidinedione, 1-methyl- 1-methyl-2-imidazolidinethione, 4,4-dimethyl-2-imidazolidinethione, 4,5-dimethyl- (1-methylethyl) -2-imidazolidinone, 1-butyl-5- 1-acetyl-3-allyl-2-imidazolidinethione, 1- (2-aminoethyl) -2-imidazolidinone, Dihydroxy-1-methyl-2-imidazolidinethione, 1- (2-hydroxyethyl) -2-imidazolidinone, 1-ethyl-5- (4-methoxyphenyl) -2-imidazolidinethione, 1,3-diethyl -4,5-dihydroxy-4,5-diphenyl-2-imidazolidinethione and 1,3-bis [ Amino) methyl] -2-imidazolidine thione is.

Citric acid, a salt thereof or a mixture thereof is included in the indium composition. Citrate salts include, but are not limited to, sodium citrate dihydrate, monosodium citrate, potassium citrate, and diammonium citrate. Citric acid, its salt or a mixture thereof may be contained in an amount of 5 g / L to 300 g / L, preferably 50 g / L to 200 g / L. Preferably a mixture of citric acid and its salts is included in the indium composition in the amounts indicated above.

Optionally, but preferably, at least one chloride ion source is included in the indium electroplating composition. The chloride ion source includes, but is not limited to, sodium chloride, potassium chloride, hydrogen chloride, or mixtures thereof. Preferably the chloride ion source is sodium chloride, potassium chloride or mixtures thereof. More preferably, the chloride ion source is sodium chloride. One or more chloride ion sources are included in the indium composition such that the molar ratio of chloride ion to indium ion is at least 2: 1, preferably from 2: 1 to 7: 1, more preferably from 4: 1 to 6: 1.

Alternatively, in addition to citric acid, its salts or mixtures thereof, one or more additional buffers may be included in the indium composition to provide a pH of from 1 to 4, preferably from 2 to 3. Buffer solutions include salts of acids and their conjugate bases. The acid may be selected from the group consisting of amino acid, carboxylic acid, glyoxylic acid, pyruvic acid, hydroxamic acid, iminodiacetic acid, salicylic acid, succinic acid, hydroxybutyric acid, acetic acid, acetoacetic acid, tartaric acid, phosphoric acid, oxalic acid, carbonic acid, ascorbic acid, , Thioacetic acid, glycolic acid, malic acid, formic acid, heptanoic acid, hexanoic acid, hydrofluoric acid, lactic acid, nitrous acid, octanoic acid, pentanoic acid, uric acid, nonanoic acid, decanoic acid, sulfurous acid, Such as methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, sulfamic acid. The acid is combined with a ^{Li +, Na +, K +} , NH 4 + or a conjugate base of (C _n H _{(2n + 1)) 4} N ⁺ salt (where n is an integer from 1 to 6).

Optionally, one or more surfactants may be included in the indium composition. Such surfactants include, but are not limited to, amine surfactants such as the commercially available tertiary amines as TOMAMINE®-QC-15 surfactants, amine oxides commercially available as TOMAMINE®-AO-455 surfactants, both available from Air Products Available; Hydrophilic polyether monoamines commercially available as SURFONAMINE 占 L-207 amine surfactant from Huntsman; Commercially available polyethylene glycol octyl (3-sulfopropyl) diethers as RALUFON® EA 15-90 surfactants; Commercially available [(3-sulfoproxy) -polyalkoxy] -? - naphthyl ether, potassium salt, commercially available as RALUFON® NAPE 14-90 surfactant, commercially available as RALUFON® EN 16-80 surfactant, Ethylene glycol octyl ether, commercially available polyethylene glycol alkyl (3-sulfopropyl) diether, potassium salt as RALUFON® F 11-3 surfactant, all available from Raschig GmbH; Commercially available EO / PO block copolymers as TETRONIC®-304 surfactants available from BSF; Ethoxylated? -Naphthols from Schaerer & Schlaepfer AG, such as ADUXOL ™ NAP-08, ADUXOL ™ NAP-03 and ADUXOL ™ NAP-06 ; Ethoxylated 2,4,7,9-tetramethyl-5-decyne-4,7-diol, such as SURFYNOL 占 484 surfactant from Air Products and Chemicals Co.; LUX ™ BN-13 surfactants, such as TIB Chemicals LUX ™ NPS surfactants, ethoxylated β-naphthols; Beta-naphthol, such as POLYMAX PA-31 surfactant available from PCC Chemax, Inc. Such surfactants are included in an amount of 1 ppm to 10 g / L, preferably 5 ppm to 5 g / L.

Optionally, the indium composition may comprise at least one grain refiner. Such crystal growth inhibitors include, but are not limited to, 2-picolinic acid, sodium 2-naphthol-7-sulfonate, 3- (benzothiazol- (UPS), bis (sulfopropyl) disulfide (SPS), mercaptopropane sulfonic acid (MPS), 3- N , N -dimethylaminodithiocarbamoyl-1 -Propanesulfonic acid (DPS), and (O-ethyldithiocarbonate) -S- (3-sulfopropyl) -ester (OPX). Preferably such a crystal growth inhibitor is included in the indium composition in an amount of from 0.1 ppm to 5 g / L, more preferably from 0.5 ppm to 1 g / L.

Optionally, the at least one inhibitor may be included in the indium composition. Inhibitors include, but are not limited to, phenanthroline and its derivatives such as 1,10-phenanthroline, triethanolamine and its derivatives such as triethanolamine lauryl sulfate, sodium lauryl sulfate and ethoxylated ammonium lauryl sulfate, polyethyleneimine and Derivatives thereof, such as hydroxypropylpolyimeneimine (HPPEI-200), and alkoxylated polymers. Such inhibitors are included in the indium composition in conventional amounts. Typically, the inhibitor is included in an amount from 1 ppm to 5 g / L.

Optionally, one or more smoothing agents may be included in the indium composition. Smoothing agents include, but are not limited to, polyalkylene glycol ethers. Such ethers include but are not limited to dimethylpolyethylene glycol ether, di-tert-butylpolyethylene glycol ether, polyethylene / polypropylene dimethyl ether (mixed or block copolymers), and octyl monomethylpolyalkylene Ether (mixed or block copolymer). Such smoothing agents are included in conventional amounts. Generally, such a smoothing agent is included in an amount of 100 ppb to 500 ppb.

Alternatively, at least one hydrogen inhibitor may be included in the indium composition to inhibit hydrogen gas formation during the indium metal electroplating. The hydrogen inhibitor comprises an epihalohydrin copolymer. The epihalohydrin includes epichlorohydrin and epibromohydrin. Typically, copolymers of epichlorohydrin are used. Such copolymers are water-soluble polymerization products of at least one organic compound comprising epichlorohydrin or epibromohydrin, and nitrogen, sulfur, oxygen atoms or combinations thereof.

Nitrogen-containing organic compounds that can be copolymerized with epihalohydrin include, but are not limited to:

One) Aliphatic chain amine;

2) An unsubstituted heterocyclic nitrogen compound having at least two reactive nitrogen moieties; And

3) A substituted heterocyclic nitrogen compound having at least two reactive nitrogen moieties and having 1 to 2 substituents selected from an alkyl group, an aryl group, a nitro group, a halogen and an amino group.

The aliphatic chain amines include but are not limited to dimethylamine, ethylamine, methylamine, diethylamine, triethylamine, ethylenediamine, diethylenetriamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octyl Amine, 2-ethylhexylamine, isooctylamine, nonylamine, isononylamine, decylamine, undecylamine, dodecylamine tridecylamine and alkanolamine.

Unsubstituted heterocyclic nitrogen compounds having at least two reactive nitrogen moieties include, but are not limited to, imidazole, imidazoline, pyrazole, 1,2,3-triazole, tetrazole, pyrazazine, 1,2 , 4-triazole, 1,2,3-oxadiazole, 1,2,4-thiadiazole, and 1,3,4-thiadiazole.

Substituted heterocyclic nitrogen compounds having at least two reactive nitrogen sites and having 1-2 substituents include, but are not limited to, benzimidazole, 1-methylimidazole, 2-methylimidazole, 1,3 - dimethylimidazole, 4-hydroxy-2-aminoimidazole, 5-ethyl-4-hydroxyimidazole, 2-phenylimidazoline and 2-tolylimidazoline.

Preferred are imidazole, pyrazole, imidazoline, 1,2,3-triazole, tetrazole, pyridazine, 1,2,4-triazole, 1,2,3-oxadiazole, At least one compound selected from 2,4-thiadiazole and 1,3,4-thiadiazole, and derivatives thereof containing one or two substituents selected from methyl, ethyl, phenyl and amino groups, Lt; / RTI > copolymer.

Some of the epihalohydrin copolymers are commercially available, such as Raschig GmbH (Ludwigshafen, Germany) and BASF (BASF, Ianville, Mich., USA) Can be prepared by the disclosed method. An example of a commercially available imidazole / epichlorohydrin copolymer is the LUGALVAN® IZE copolymer available from BASF.

The epihalohydrin copolymer can be formed by reacting an epihalohydrin with the nitrogen, sulfur or oxygen containing compound described above under any suitable reaction conditions. For example, in one method, the two materials are dissolved in an appropriate concentration in the body of a mutual solvent and reacted therein, for example, for 45 to 240 minutes. The aqueous solution of the chemical product of the reaction is isolated by distillation of the solvent and then added to the body of water acting as electroplating solution once the indium salt is dissolved. In another method, the two materials are placed in water and heated to 60 DEG C with constant vigorous stirring until they are dissolved in water by reaction.

A wide range of reaction reagents to epihalohydrins, such as from 0.5: 1 to 2: 1, can be used. Typically, the molar ratio is from 0.6: 1 to 2: 1 mol, more typically the molar ratio is from 0.7 to 1: 1, most typically the molar ratio is 1: 1.

Additionally, the reaction product may be further reacted with one or more reagents before the electroplating composition is completed by the addition of the indium salt. Thus, the described products can be further reacted with at least one reagent of ammonia, aliphatic amines, polyamines and polyimines. Typically, the reagent is at least one species of ammonia, ethylenediamine, tetraethylenepentamine, and polyethyleneimine having a molecular weight of at least 150, although other species may be used that meet the definition described herein. The reaction can take place in water with stirring.

For example, a reaction takes place between a reaction product of epichlorohydrin and a nitrogen-containing organic compound as described above, and a reagent selected from ammonia, an aliphatic amine, and at least one of an arylamine or polyimine, , ≪ / RTI > at a temperature of from 30 DEG C to 60 DEG C, such as from 45 minutes to 240 minutes. The molar ratio of the reaction product of the nitrogen containing compound-epichlorohydrin reaction and the reagent is typically 1: 0.3-1.

The epihalohydrin copolymer is included in the present composition in an amount from 0.01 g / L to 100 g / L. Preferably, the epihalohydrin copolymer is contained in an amount of 0.1 g / L to 80 g / L, more preferably it is in an amount of 0.1 g / L to 50 g / L, most preferably 1 g / L to 30 g / L.

The indium composition may be used to deposit a substantially uniform, void-free indium metal layer on the metal layer of the various substrates. The indium layer is also substantially free of dendrites. The indium layer preferably has a thickness of 10 nm to 100 占 퐉, more preferably 100 nm to 75 占 퐉.

The device used to deposit the indium metal on the metal layer is a conventional device. Preferably, a conventional soluble indium electrode is used as the anode. Any suitable reference electrode may be used. Typically, the reference electrode is a silver chloride / silver electrode. The current density may range from 0.1 ASD to 10 ASD, preferably from 0.1 to 5 ASD, more preferably from 1 to 4 ASD.

The temperature of the indium composition during the indium metal electroplating may range from room temperature to 80 캜. Preferably, the temperature ranges from room temperature to 65 ° C, more preferably from room temperature to 65 ° C. Most preferably, the temperature is room temperature.

The indium composition can be used to electroplating indium metal on nickel, copper, gold and tin layers of various substrates, including electronic devices, magnetic field devices and components for superconducting MRI. Preferably, indium is electroplated onto nickel. The metal layer is preferably in the range of 10 nm to 100 μm, more preferably 100 nm to 75 μm. The indium compositions can also be used in conventional photoimaging methods for electroplating indium metal small diameter solder bumps on a variety of substrates such as silicon wafers. The small diameter bumps preferably have a diameter of 1 占 퐉 to 100 占 퐉, more preferably 2 占 퐉 to 50 占 퐉, and an aspect ratio of 1 to 3.

For example, the indium composition can be used to electroplate indium metal on components for electrical devices that function as TIMs, such as but not limited to ICs, microprocessors in semiconductor devices, MEMS, and components for optoelectronic devices. Such electronic components may be included in printed circuit boards and in melt-sealed chip-scale and wafer-level packages. Such a package typically includes a hermetically sealed enclosed volume formed between the base substrate and the lid, and the electronic device is disposed in the sealed volume. The package is provided for containment and protection of the enclosed device from atmospheric water vapor and contamination outside the package. The presence of contamination and water vapor in the package can cause problems such as optical loss in the case of optoelectronic devices and other optical components as well as corrosion of metal parts. The low melting temperature (156 ° C) and high thermal conductivity (~ 82 W / m ° K) are characteristics that make the indium metal very desirable for use as a TIM.

In addition to TIM, the indium composition can be used to electroplate the underlying layer on the substrate to prevent whisker formation in electronic devices. The substrate includes, but is not limited to, a film carrier for mounting electrical or electronic components or parts such as semiconductor chips, printed circuit boards, lead frames, contact elements such as contacts or terminals, and good appearance and high operational reliability And the plated structural member.

The following examples further illustrate the invention, but are not intended to limit the scope of the invention.

Example 1 (comparative)

A photoresist patterned silicon wafer from Silicon Valley Microelectronics, Inc., having a plurality of vias with a diameter of 75 [mu] m and a copper seed layer at the base of each via, Electroplated with a nickel layer using a NIKAL (TM) BP nickel electroplating bath available from Dow Advanced Materials. Nickel electroplating was performed at 55 占 폚 for 120 seconds at a cathode current density of 1 ASD. The current was supplied to the conventional rectifier. The anode was a soluble nickel electrode. After plating, the silicon wafer was removed from the plating bath, and the photoresist was peeled from the wafer using a SHIPLEY BPR (TM) Photostripper available from Dow Advance Materials, and rinsed with water. The nickel deposits looked substantially smooth, and there were no observable dendrites on the surface. 1A is an optical image of one of the nickel plated copper seed layers taken with a LEICA (TM) optical microscope.

The following aqueous indium electrolytic compositions were prepared:

Although the nickel layer electroplating process described above was repeated on another set of photoresist patterned wafers, after the electroplating of the single nickel layer, the nickel plated silicon wafer was immersed in the indium electroplating composition to deposit the indium metal on the nickel Plated. The indium electroplating was performed at 25 DEG C for 30 seconds at a current density of 4 ASD. The pH of the indium electroplating composition was 2.4. The anode was an indium-soluble electrode. After the indium was plated on the nickel, the photoresist was peeled from the wafer and the shape of the indium deposit was observed. All indium deposits appeared rough.

Figure Ib is an optical image of one of the electroplated indium metal deposits on the nickel layer. The indium deposits were very rough, unlike the nickel deposits shown in FIG. 1A.

Example 2

The procedure described in Example 1 above was repeated, except that the indium electroplating composition comprised the following components:

A nickel plated silicon wafer was immersed in the indium electroplating composition and the indium metal was electroplated onto the nickel. Indium electroplating was performed at 25 DEG C for 30 seconds at a current density of 4 ASD. The pH of the plating composition was 2.4. The anode was an indium-soluble electrode. After the indium was electroplated on the nickel surface, the photoresist was peeled from the wafer and the indium form was observed. All indium deposits appeared uniform and smooth.

 Figure 2 is an optical microscope image of one of the electroplated indium metal deposits on the nickel layer. The indium deposits appeared smooth as opposed to the indium deposits of FIG. 1B.

Example 3

The method described in Example 1 was repeated except that the silicon wafer was patterned with a photoresist to have a rectangular via having a length of 50 mu m and the indium electroplating composition comprised the following components:

A nickel plated silicon wafer was immersed in an indium electroplating composition and the indium metal was electroplated onto nickel. Indium electroplating was performed at 25 DEG C for 30 seconds at a current density of 4 ASD. The pH of the indium electroplating composition was 2.4. After the indium was plated on the nickel, the photoresist was peeled from the wafer and the shape of the indium deposit was observed. All indium deposits appeared uniform and smooth.

Figure 3 is an optical microscope image of one of the electroplated indium metal deposits on the nickel layer. The indium deposits appeared smooth as opposed to the indium deposits of FIG. 1B.

Example 4

The procedure described in Example 2 above was repeated, except that the indium electroplating composition comprised the following components:

A nickel plated silicon wafer was immersed in the indium electroplating composition and the indium metal was electroplated onto the nickel. The indium electroplating was performed at 25 DEG C for 30 seconds at a current density of 4 ASD. The pH of the plating composition was 2.4. The anode was a soluble nickel electrode. After the indium was plated on the nickel, the photoresist was peeled from the wafer and the shape of the indium deposit was observed. All indium deposits appeared uniform and smooth.

Figure 4 is an optical microscope image of one of the electroplated indium metal deposits on the nickel layer. The indium deposits appeared smooth as opposed to the indium deposits of FIG. 1B.

Example 5

The procedure described in Example 2 above was repeated, except that the indium electroplating composition comprised the following components:

A nickel plated silicon wafer was immersed in the indium electroplating composition and the indium metal was electroplated onto the nickel. The indium electroplating was performed at 25 DEG C for 30 seconds at a current density of 4 ASD. The pH of the plating composition was 2.4. The anode was a soluble nickel electrode. After the indium was plated on the nickel, the photoresist was peeled from the wafer and the shape of the indium deposit was observed. All indium deposits appeared uniform and smooth.

5 is an optical microscope image of one of the electroplated indium metal deposits on the nickel layer. The indium deposits appeared smooth as opposed to the indium deposits of FIG. 1B.

Example 6

 The procedure described in Example 2 above was repeated, except that the indium electroplating composition comprised the following components:

The pH of the plating bath during electroplating is 2.4. A nickel plated silicon wafer was immersed in the indium electroplating composition and the indium metal was electroplated onto the nickel. The indium electroplating was performed at 25 DEG C for 11 seconds at a current density of 4 ASD. After the indium was electroplated on the nickel surface, the photoresist was peeled from the wafer and the indium form was observed. It is expected that all of the indium deposit will appear uniformly and smoothly in substantially the same manner as shown in Figs. 2-5.

Example 7

 An indium electroplating composition is prepared comprising the following components:

The pH of the plating bath during electroplating is 2.4. A nickel plated silicon wafer was immersed in the indium electroplating composition. And indium metal were electroplated onto nickel. The indium electroplating was performed at 25 DEG C for 11 seconds at a current density of 4 ASD. After the indium was electroplated on the nickel surface, the photoresist was peeled from the wafer and the indium form was observed. It is expected that the indium deposit will appear to be substantially uniform and smooth in substantially the same manner as shown in Figs. 2-5.

Example 8

An indium electroplating composition is prepared comprising the following components:

The pH of the plating bath during electroplating is 2.4. A nickel plated silicon wafer was immersed in the indium electroplating composition. And indium metal were electroplated onto nickel. The indium electroplating was performed at 25 DEG C for 11 seconds at a current density of 4 ASD. After the indium was electroplated on the nickel surface, the photoresist was peeled from the wafer and the indium form was observed. It is expected that the indium deposit will appear to be substantially uniform and smooth in substantially the same manner as shown in Figs. 2-5.

Example 9

 The procedure described in Example 2 above was repeated, except that the indium electroplating composition comprised the following components:

A nickel plated silicon wafer was immersed in the indium electroplating composition and the indium metal was electroplated onto the nickel. The indium electroplating was performed at 25 DEG C for 30 seconds at a current density of 4 ASD. The pH of the plating composition was 2.4. After the indium was plated on the nickel, the photoresist was peeled from the wafer and the shape of the indium deposit was observed. All indium deposits appeared uniform and smooth. 6 is an optical microscope image of indium electroplated from the plating bath of Table 9; As shown in Figure 6, the indium deposits were uniform and smooth.

Claims (16)

At least one indium ion source, at least one 2-imidazolidinedione compound, and citric acid, a salt thereof, or a mixture thereof. 3. The composition of claim 1, wherein the at least one 2-imidazolidinedione compound has the formula:

Wherein R ₁ and R ₂ are independently selected from the group consisting of hydrogen, linear or branched (C ₁ -C ₁₂ ) alkyl, linear or branched hydroxy (C ₁ -C ₁₂ ) alkyl, linear or branched (C ₁ -C ₁₂ ) alkoxy, linear or branched (C ₃ -C ₁₂₎ allyl, amino, primary, secondary, or tertiary amino (C ₁ -C ₁₂₎ alkyl, acetyl, and substituted or unsubstituted aryl (C ₁ -C ₁₂ ) Alkyl; < / RTI > R _3, R _4, R ₅ and R ₆ is hydrogen, linear or branched (C ₁ -C ₁₂₎ alkyl, hydroxyl, linear or branched, hydroxy (C ₁ -C ₁₂₎ alkyl, primary, secondary, , Or tertiary amino, aryl, linear or branched (C ₁ -C ₁₂ ) alkoxy, primary, secondary, or tertiary amino (C ₁ -C ₁₂ ) alkyl and acetyl. Substituents on the aryl group include, but are not limited to, linear or branched (C ₁ -C ₅ ) alkyl, hydroxyl, hydroxy (C ₁ -C ₅ ) alkyl, (C ₁ -C ₃ ) alkoxy, (C ₁ -C ₅ ) alkyl. The method of claim 2, wherein the at least one 2-imidazolidinedione compound is selected from the group consisting of 2-imidazolidinedione, 1,3-dimethyl-2-imidazolidinethione, Imidazolidinone, imidazolidinethione, 1,3-diethyl-2-imidazolidinethione, 1-methyl-2- imidazolidinethione, 4,4- (1-methyl-2-imidazolidin) thione, 1-butyl-5- Ethyl-2-imidazolidinethione, 1,3-diallyl-2-imidazolidinethione, 1-acetyl- Imidazolidinethione, 4,5-dihydroxy-1-methyl-2-imidazolidinethione, 1- (2-hydroxyethyl) 2-imidazolidinethione, 1-ethyl-5- (4-methoxyphenyl) -2-imidazolidinethione, 1,3-diethyl-4,5-dihydroxy-4,5-diphenyl-2-imidazolidine And 1,3-bis [(cyclohexylamino) methyl] -2-imidazole, the composition is selected from the Jolly Dean thione. The composition of claim 1, wherein the at least one 2-imidazolidinedione compound is included in the composition in an amount of 0.005 g / l to 5 g / l. The composition of claim 1, wherein the composition further comprises at least one chloride ion source, wherein the molar ratio of chloride ion to indium ion is greater than or equal to 2: 1. 6. The composition of claim 5, wherein the molar ratio of chloride ion to indium ion is from 2: 1 to 7: 1. 7. The composition of claim 6, wherein the molar ratio of chloride ion to indium ion is from 4: 1 to 6: 1. The composition according to claim 1, wherein the amine surfactant, ethoxylated naphthol, sulfonated naphthol polyether, (alkyl) phenol ethoxylate, sulfonated alkylalkoxylate, alkylene glycol alkyl ether and sulfopropylated polyalkoxylated beta-naphthol alkaline salt ≪ / RTI > wherein the composition further comprises at least one surfactant selected from the group consisting of surfactants. The composition of claim 1, further comprising at least one copolymer of the reaction product of an epihalohydrin and at least one nitrogen-containing organic compound. a) providing a substrate comprising a metal layer;
b) contacting the substrate with an indium electroplating composition comprising at least one indium ion source, at least one 2-imidazolidinedione compound, and a citric acid, a salt of citric acid, or a mixture thereof; And
c) electroplating the indium metal layer on the metal layer of the substrate using the indium electroplating composition.  11. The method of claim 10, wherein the at least one 2-imidazolidinedione compound is included in the indium electroplating composition in an amount of 0.005 g / l to 5 g / l. 11. The method of claim 10, wherein the indium electroplating composition further comprises at least one chloride ion source, wherein the molar ratio of chloride ion to indium ion is at least 2: 1. 11. The method of claim 10, wherein the metal layer is nickel, copper, gold or tin. 14. The method of claim 13, wherein the metal layer is nickel. 11. The method of claim 10, wherein the metal layer is 10 nm to 100 탆 thick. 11. The method of claim 10, wherein the indium metal layer is 10 nm to 100 탆 thick.

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