The present invention relates to a method for reducing tin whisker formation in tin deposits by plating on an underlying metal tin deposits which are essentially free of compressive stress or are predominantly in a predetermined crystal orientation that essentially matches that of the underlying metal in order to inhibit tin whisker growth. The deposits preferably exhibit no compressive stress or exhibit a tensile stress. Also, the most preferred crystal orientation is one that is the same as that of the underlying metal. The deposit preferably contains at least 95 % tin and optionally at least one alloying element of silver, bismuth, copper or zinc in an amount of 5 % or less. Advantageously, the tin deposits are provided during electroplating from a specially formulated plating solution that contains a crystal orientation surfactant.

Minimizing whisker growth in tin electrodeposits

A metal dissolving liquid and method for stripping tin and solder coatings, including the underlying tin-copper alloy, from the copper substrate of a printed circuit board. The liquid includes an aqueous solution of nitric acid in an amount sufficient to dissolve solder and tin, a source of ferric ions in an amount sufficient to dissolve tin-copper alloy, a source of halide ions in an amount sufficient to solubilize tin, an effective amount of methylsulfonic acid as promoter for complete stripping, and a source of an organic, water soluble amine. The combination of ingredients will substantially eliminate sludge formation, reduce attack on the copper substrate and provide a bright copper finish after solder removal. A liquid further including organic triazoles including benzotriazole in amounts not more than about 5% by weight and sulfamic ions in amounts not more than about 2.5% by weight.

Solder and tin stripper composition

Improved electrolytic tin deposition from aqueous, acid electroplating baths is achieved by addition of a new formula of brighteners. These results are achieved by further addition of unsaturated aliphatic acids or their derivates and still better results are achieved by further addition of certain heterocyclic quarternary compounds.

Bright tin electroplating bath

The invention relates to a metallized solar cell and the method of making thereof that includes depositing a metal or metals such as silver, nickel, copper, tin, indium, gallium, or selenium or their alloys on solar cells in a manner to form more substantial and robust electrical contacts that can carry current more efficiently and effectively or to provide the active layers required to convert sunlight into electricity. These deposits also protect the underlying metallic materials from corrosion, oxidation or other environmental changes that would deleteriously affect the electrical performance of the cell. The invention also relates to the use of specialized electroplating chemistries that minimize residual stress and/or are free of organic sulfonic acids to minimize chemical attack on solar cell substrates or prior metallizations that include organic and/or inorganic binders or related materials for depositing the initial metallic portions of the cell.

Method of metallizing solar cell conductors by electroplating with minimal attack on underlying materials of construction

This invention relates to the electrodeposition of tin; acid tin plating compositions, acid tin plating baths; to processes for the electrodeposition of bright tin in the presence of glacial acrylic acid, at least one non-ionic alkoxylated wetting agent, and as a novel brightener, the reaction product of hexan-2,5dione and a compound selected from the group consisting of homocyclic aromatic aldehydes and 5-membered ring heterocyclic aldehydes, wherein the aldehyde group is bonded directly to the aromatic ring, conjugated aromatic ring or 5-membered ring heterocyclic group, said ring or group being otherwise inertly substituted or unsubstituted; to said novel brighteners; and a method of producing said novel brighteners.

Bright acid tin plating

An aqueous bath for electroplating tin upon various conductive substrates contains stannous ion, sulfate radical, an imidazoline derivative, a carbinamine compound, and a cyclic aldehyde or ketone brightener. The bath is highly acid and is operable to produce dense, smooth, bright, adherent deposits, particularly at relatively high current densities. These deposits exhibit excellent solderability as plated and after prolonged aging. In addition, the bath avoids step plating when holes are present in the workpiece, and it minimizes the tendency for pitting to occur in the deposit.

Tin plating bath and method

A COMPOSITION FOR CLEANING ALUMINUM COMPRISES AN AQUEOUS BATH OF UREA NITRATE AND FERRIC SULFATE. THE BATH IS EFFECTIVE AT AMBIENT TEMPERATURE TO RAPIDLY REMOVE SMUT FROM ALUMINUM ALLOY ARTICLES, AND THE RATE OF ACTIVITY IS SUBSTANTIALLY UNIFORM THROUGHOUT THE USEFUL LIFE OF THE COMPOSITION.

Composition for cleaning aluminum and method utilizing same

AN AQUEOUS BATH FOR ELECTROPLATING TIN UPON METAL SURFACES CONTAINS STANNOUS ION, SULFATE RADICAL, A SURFACEACTIVE SULFATED POLYOXYALKYL CARBINAMINE AND AN IMIDAZOLINE DERIVATIVE THE BATH HAS A HYDROGEN ION CONCENTRA TION OF ABOUT 09 TO 41 GRAMS PER LITER, AND IT OPERATES EFFECTIVELY EVER A WIDE RANGE OF CURRENT DENSITIES TO PRODUCE DESIRABLE DEPOSITS AT RELATIVELY HIGH PLATING RATES

Joseph F Conoby

Papers

Tin plating bath and method

Composition for cleaning aluminum and method utilizing same

Method and composition for electroplating tin