Macdermid, Incorporated

John J Grunwald

Peter E Kukanskis

Eugene D D'Ottavio

Michael S Lombardo

Elaine F Jacovich

Donald R Ferrier

David A Sawoska

Allen C Spencer

David Sawoska

Harold L Rhodenizer

Rachel Goldstein

The present invention relates to a process for the manufacture of printed circuit boards. The method contemplates a novel processing sequence for this manufacturing process which method is particularly versatile in reducing the number of steps and variety of chemicals currently necessary to produce the circuit boards.

Method for the manufacture of printed circuit boards

Photo resist image layers, particularly those used for high resolution geometries in microelectronic applications, are stabilized against distortion or degradation by the heat generated during subsequent etching, ion implantation processes and the like, by the application of a film of a thermally stabilizing agent prior to post-development bake of the image layer. High temperature resistant film forming polymers, of which gelatin and gelatin hydrolysates are preferred examples, are employed as thermally stabilizing agents. The process serves to achieve thermal stabilization of the photoresist image layer without significantly affecting the ease of subsequent stripping of the layer. It is particularly effective when used to thermally stabilize positive resist images derived from photoresist systems based on novolak resins.

Thermally stabilized photoresist images

Photo resist image layers, particularly those used for high resolution geometries in microelectronic applications, are stabilized against distortion or degradation by the heat generated during subsequent etching, ion implantation processes and the like, by the application of a film of a thermally stabilizing agent prior to post-development bake of the image layer. The process serves to achieve thermal stabilization of the photoresist image layer without significantly affecting the ease of subsequent stripping of the layer. It is particularly effective when used to thermally stabilize positive resist images derived from photoresist systems based on novolak resins.

A method of electroless deposition of metal on a non-conductive substrate is disclosed and comprises treating a substrate prior to electroless deposition with a catalyst composition containing a mixed tin-palladium catalyst. An improvement in metal deposition is obtained by contacting the treated substrate with an alkaline accelerator bath containing an agent which oxidizes the tin.

Oxidizing accelerator

Electroless copper deposition solutions, and method of electrolessly depositing copper onto a workpiece using these solutions, are disclosed. The solutions contain, in addition to water as the usual solvent, a soluble source of copper ions, a complexing agent or mixture of agents to maintain the copper in solution, and a copper reducing agent effective to reduce the copper ions to metallic copper as a deposit or plating on a prepared surface of a workpiece brought into contact with the solution. The invention comprehends replacing the usual formaldehyde-type reducing agents of commercial electroless copper baths with inorganic non-formaldehyde-type agents, for example hypophosphites, by coordinating the particular complexing agents employed and the bath pH, to effect reduction of cupric ions to a metallic copper plating on a prepared surface of a substrate, wherein the resulting electroless metal deposit has conductive properties at least satisfactory for build-up of additional thickness of metal by standard electroplating techniques. Improvement over the prior formaldehyde-reduced electroless copper solutions is obtained in that the invention teaches those skilled in the art how to achieve satisfactory copper deposition over longer periods of bath operation than has been practical heretofore. Fluctuations in component concentration and bath temperatures are inherent and unavoidable in the course of commercial use of the bath and these are normally detrimental to protracted use of formaldehyde-reduced copper solutions. In the present invention, bath stability is maintained better, in spite of these inherent fluctuations.

Electroless copper deposition solution using a hypophosphite reducing

Electroless copper deposition solutions, and method of continuously electrolessly depositing copper onto a workpiece using these solutions, are disclosed. The solutions contain, in addition to water as the usual solvent, a soluble source of copper ions, a complexing agent or mixture of agents to maintain the copper in solution, a non-formaldehyde copper reducing agent, such as hypophosphite, effective to reduce the copper ions to metallic copper as a deposit or plating on a prepared surface of a workpiece brought into contact with the solution, and a soluble source of non-copper metallic ions, such as nickel or cobalt ions, which act as an autocatalysis promoter to enable continuous plating using the solutions. The solutions are maintained in an alkaline condition and preferably in a pH range of 11-14 through the addition of pH adjusters. The properties of plating baths using the solutions, such as bath stability as well as plating process parameters such as plating rate, and the quality of deposit may be advantageously controlled through the appropriate selection of the non-copper metallic ion added and the complexing agent used. Optional additives, such as polymers, wetting agents, and various soluble unsaturated organic compounds, may also be utilized to influence these variables.

Method and composition for continuous electroless copper deposition

Electroless copper deposition solutions, and method of electrolessly depositing copper onto a workpiece using these solutions, are disclosed. The solutions contain, in addition to water as the usual solvent, a soluble source of copper ions, a complexing agent or mixture of agents to maintain the copper in solution, and a copper reducing agent effective to reduce the copper ions to metallic copper as a deposit or plating on a prepared surface of a workpiece brought into contact with the solution. The invention comprehends replacing the usual formaldehyde-type reducing agents of commercial electroless copper baths with non-formaldehyde-type agents, specifically hypophosphites, by coordinating the particular complexing agents employed and the bath pH, to effect reduction of cupric ions to a metallic copper plating on a prepared surface of a substrate, wherein the resulting electroless metal deposit has conductive properties at least satisfactory for build-up of additional thickness of metal by standard electroplating techniques. Improvement over the prior formaldehyde-reduced electroless copper solutions is obtained in that the invention teaches those skilled in the art how to achieve satisfactory copper deposition over longer periods of bath operation than has been practical heretofore. Fluctuations in component concentration and bath temperatures are inherent and unavoidable in the course of commercial use of the bath and these are normally detrimental to protracted use of formaldehyde-reduced copper solutions. In the present invention, bath stability is maintained better, in spite of these inherent fluctuations.

Electroless copper composition solution using a hypophosphite reducing

A process is disclosed comprising laminating an anodically treated aluminum surface against a thermoset plastic substrate, whereby the surface of the substrate after chemically removing the aluminum has an improved affinity for the adherence thereon of electrolessly deposited metal films.

Process of preparing thermoset resin substrates to improve adherence of

An improvement is obtained in the bond strength between members of a laminate comprising a plastic substrate and a metal film through a process of first laminating to the plastic substrate a thin, sacrificial, anodized metal foil while providing at the interface prior to laminating of the foil to the plastic at least a mono molecular film of an organic silicon compound. After laminating the treated metal foil to the substrate under heat and pressure, the foil is chemically stripped from the substrate, leaving a surface of improved receptivity for conventional electroless plating and electroplating procedures, or other metallizing techniques. The final metal film when applied to the substrate exhibits consistently better adhesive strength than is obtained without the organic silicon treatment of the interface, especially in respect to adhesive strength at elevated temperature.

Method of making metal-plastic laminates

An improvement is obtained in the bond strength between members of a laminate comprising a plastic substrate and a metal film through a process of first laminating to the plastic substrate a thin, sacrificial, anodized metal foil by heat and pressure, chemically stripping the foil from the substrate surface, activating the surface for electroless plating and electrolessly depositing a metal thereon, wherein the substrate is contacted with an aqueous solution containing an organic silicon compound at some stage subsequent to said chemical stripping operation. The final metal film when applied to the substrate exhibits consistently better adhesive strength than is obtained without the organic silicon treatment.

Method of improving the adhesion between a molded resin substrate and a

Circuit boards for electronic equipment are produced in which the circuit-forming conductor metal is deposited on a suitably catalyzed and masked resin substrate by an all-additive electroless deposition technique, in which the characterizing feature is the use of a two-stage metal deposition to build up the desired total thickness of metal. In the first stage a fine grained, thin deposit of metal is produced on the substrate which is then water rinsed and immersed in a second metal bath having a sufficiently high rate of deposition to produce the desired total thickness of metal in a commercially practical period of time. Improved adhesion of plated metal to the resin substrate, both before and after thermal shock, is achieved by resort to this two-stage plating procedure.

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New Haven, CT, United States of America

John J Grunwald