Schering Aktiengesellschaft

Atotech Deutschland Gmbh

Hartmut Mahlkow

Hans-Jurgen Ehrich

Ludwig Stein

Christian Wunderlich

Petra Backus

Waltraud Strache

Heinrich Meyer

Horst Blasing

Christian Sparing

Hans-Jürgen Schreier

Hubert-Matthias Seidenspinner

Klaus Gedrat

Olaf Claussen

Michael Romer

Jurgen-Otto Besenhard

Joachim Wolff

Hans J Ehrich

Wolfgang Clauss

Gunther Rosskamp

Jurgen Skupsch

Carl Hutchinson

Joachim Grapentin

Hans-Peter Gausmann

The problem in forming solderable and bondable layers on printed circuit boards is that the surfaces tarnish after storage of the boards prior to further processing (mounting of the electrical components), thus affecting solderability and bondability. In order to overcome this problem it is suggested to deposit, in a first method step, a first metal which is more noble than copper to the printed circuit board and to plate silver in a second method step with the proviso that the first metal be deposited at a rate that is at most half the rate of silver in the second method step when the first metal is silver.

Immersion plating of silver

Known methods of improving the solderability of copper surfaces on printed circuit boards present the disadvantage that outer layers of an irregular thickness are formed at the metal surfaces, that these layers are very expensive or that the constituents used in manufacturing them are harmful to the environment. Furthermore, the metal surfaces are to be suited to form bond connections as well as electrical contacts. To overcome these problems there are disclosed a bath and a method of electroless plating of silver by way of charge exchange reaction on surfaces of metals that are less noble than silver, more particularly on copper, that contain at least one silver halide complex and not containing any reducing agent for Agions.

Bath and method of electroless plating of silver on metal surfaces

Process for the production of at least one solderable surface in selected solder regions and of at least one functional surface in function regions differing from the solder regions on circuit carriers provided as well as of corresponding circuit carriers.

Method for producing solderable and functional surfaces on circuit carriers

Method and solution for producing gold coating

A formaldehyde-free chemical bath containing a palladium salt, a nitrogenated completing agent, and formic acid or formic acid derivatives, at a pH of greater than 4 and a process of using the chemical bath for depositing on a metal surface an adhesive, permanently glossy, bright palladium layer with few pores. The metal surface may be pretreated in a cementation palladium bath. The metal surface contains at least one of copper, nickel, and cobalt, as well as their alloys with one another and/or with phosphorus or boron.

palladium layers deposition process

A method for coating surfaces of a non-conductor with finely particulate solid particles by substrate-induced coagulation, including the steps of: contacting the non-conductor with a first solution containing a first polar solvent and at least one coagulation initiator comprising high molecular weight material; and, subsequently contacting the non-conductor with a dispersion which contains a second polar solvent and: a) finely particulate solid particles, b) at least one surfactant for preventing the sedimentation of the solid particles, and c) a salt, essentially free of tin ions, for selectively destabilizing the dispersion.

Method for coating surfaces with finely particulate materials

A conditioning means for basis material for producing printing circuits is an alkaline solution of a halogen-free palladium salt and 2-aminopyridine.

Conditioning means for printed circuits

A process is disclosed for the adhesive metallization of synthetic materials, by means of pre-treatment of the synthetic materials and subsequent activation, as well as chemical and, if necessary, galvanic metal deposition, characterized by pre-treating the synthetic materials initially with an alkaline solution of an oxidation agent and then with a metal salt solution.

Process for the adhesive metallization of synthetic materials

A device and method for the treatment of printed circuit boards with process solutions, in which the boards being treated are continually vertically moved by a transporting conveyer above an accumulating reservoir and below spraying nozzles which apply a process solution to the side surfaces of each board. Two collecting receivers are arranged in mirror-inverted relationship at two sides of the boards being treated. The reservoir, into which the process solution drains from the receivers and the boards, is connected to the spraying nozzles by tubular conduits, provided with regulating valves, in a closed circuit, whereby the accumulated solution is fed back to the nozzles.

Method and device for the treatment of printed circuit boards

A process for the adhesive metallization of polyimide through pretreating of the polyimide and subsequent activation, as well as chemical metallization, if necessary, followed by galvanic metal deposition, characterized in that the polyimide is pretreated with an aqueous solution of alkali hydroxide and an organic nitrogen compound such as one selected from the group consisting of N,N,N', N'-tetra-(2-hydroxypropyl)-ethylenediamine, ethylenediaminetetraacetic acid and nitrilotriacetic acid. The plastics metallized according to the present invention find use as shaped parts, preferably in the fields of electrical engineering and electronics.

Adhesive metallization of polyimide

A method for producing printed circuits. An epoxy resin reinforced with glass fiber is used as basis material, coated with copper, drilled and activated. In one embodiment, the circuit diagram is applied after covering the non-desired regions with a resistance, by screen or photo printing. A nickel, cobalt, or nickel-cobalt layer is deposited onto the circuit, the circuit is covered with a solder prevention lacquer, then the eyes and bore holes are covered with copper. Alternatively, after pre-treatment and activation, all areas except the soldering eyes and bore holes are covered with resist, a nickel, cobalt or nickel-cobalt layer is applied, the circuit diagram is printed using a resist, and the eyes and bore hole are treated as above.

Method for producing printed circuits

A process for the preparation of metal patterns on insulating carriers by photochemical means, in particular for the preparation of printed circuits, is described, in which the carrier is treated with a photo-sensitizer in the absence of wetting agents; the carrier is irradiated in a manner corresponding to the desired pattern with a radiation source; the metal seeds formed on the surface are augmented with an aqueous palladium-salt solution; a nickel layer is deposited with a nickel or nickel-cobalt bath; the metal layer is treated with an aqueous solution containing a complex-forming agent for copper-(I) ions; and a copper layer is deposited with a currentless coppering bath.

Process for preparation of metal patterns on insulating carrier materials

An activating agent for application to the unactivated surface of an organic polymer to prepare the surface for chemical metallization comprises an aqueous solution of (a) a water soluble metal salt of an inorganic acid, the metal being silver, gold, or a platinum group metal, and (b) an amount of a ligand-forming organic nitrogen compound sufficient to form a water soluble coordination complex with the metal salt, the solution having a pH between 2.2 and 7, the metal concentration being between about 0.1 and about 1 gram per liter.

Growing community of inventors

Berlin, Germany

Hartmut Mahlkow