DD228835A1 - LASER ACTIVATION OF DIELECTRIC SURFACES FOR PARTIAL CHEMICAL-REDUCED METAL SEPARATION - Google Patents

Abstract

The method allows the formation of conductor, contact layer and resistor structures and magnetic layers on dielectric surfaces. A programmed laser beam, when exposed to the non-activated dielectric surface, partially creates a catalytic activity required for the deposition of metal layers from chemical-reductive layers. The metal layer structures can be deposited to the desired layer thickness or optionally galvanically strengthened.

Description

Title of the invention

Laser activation of dielectric surfaces for partial chemical reductive metal deposition

Field of application of the invention

The method relates to the partial activation of dielectric surfaces by laser beams for the subsequent additive chemical-reduction and optionally galvanic deposition of layers or layer systems.

Characteristic of the known technical solutions

In addition to the subtractive technique, additive methods using laser beams and chemical deposition methods are known. Thus, a photoemulsion is used for activation in Fotoeinbrennverfahren (GDR Patent 153 950), released from the catalytically active nuclei by laser beams and burned out the remnants of the photoemulsion in a baking process and the germs are fixed on the surface. The process is laborious. For example, the photoemulsion must contain defined nuclei sizes, its viscosity must be maintained by high temperature constancy, and the darkroom and precious metal nuclei are necessary.

Surface films of chemically reductive baths become metal structures on activated surfaces by laser beams

deposited (DDR patent 1 579 89). The previous activation of the surface with noble metal gels from solutions in a two-stage process can lead to carryover of germs into the chemical reductive baths and thus to instabilities. In addition, further metallization of the laser-generated metal structures in chemical reductive baths to increase the layer thickness or the generation of layer systems of several metal layers is not possible, since then there is a total base metallization of the activated surface «

In the two-stage activation laser beams are used for sensitization in the process of chemical reduction deposition (DDR patent 200 968). The nucleating metal ions cover the entire surface. There is a danger that they will be chemisorbed at non-reducible sites and reduced to germs by the existing reducing agent in the subsequent chemical etching baths. This can lead to metal deposition at undesired sites of the surface (wild separation).

It is known that a previously non-activated surface, which is covered with a bath liquid film of a chemical reductive bath, activated by an incident laser beam of appropriate wavelength and thus simultaneously the metal deposition from the chemical-reductive bath film is initiated. This metal structure can be further metalated in the same or another chemically reductive or optionally galvanic bath. Ensuring a permanent Flüssigkeits.es from a chemical-reductive bath on the surface difficulties in process control, especially in the adjustment of the laser in small structures.

It is also known that a metal suspension with an organic binder, is applied to the cleaned surface and after drying at room temperature, the surface of a programmed laser beam with the

Metal suspension and the substrate adapted parameters is set aasgesetzt. In the process, metal nuclei are formed on the surface parts treated by the laser beam, which are fixed in the substrate by the laser with high adhesive strength. However, the Best of the metal powder on the not treated by the laser beam points measure again be removed from the surface in a complex washing process, before a re-metallization of the metal structures formed by the laser is possible. If the metal powder is not removed quantitatively from the surface, contamination may occur in the subsequent chemical reductive baths, which may lead to decomposition.

Object of the invention

The invention has the object to provide an additive MetalUsierungsverfahren for partial deposition of metal structures on dielectric surfaces, the process being technologically simple, avoiding carryover of metal nuclei in subsequent chemical reductive baths and no prior activation of the entire surface with metals or metal ions , which can lead to the separation of wild animals in unwanted places.

Explanation of the essence of the invention

The starting point is that a partial deposition of metal on non-activated dielectric surfaces by simultaneous partial activation of the surface and deposition of the metal structure from the surface covering bath liquid by a laser beam of appropriate wavelength difficulties in process control, especially by the necessary constancy in the Badfilmdicke.

According to the invention this is achieved in that first the

dielectric surface is partially activated by a laser beam of appropriate wavelength, power and pulse shape, duration and repetition frequency. In doing so, the chemical potential of the surface treated with the laser beam is increased. It is at the irradiated sites a catalytic activity for the chemically-red 'deposition to record, so that in these areas partially partially a chemically-reductive metal deposition is initiated in subsequent suitable chemical-reducing metallization. The metal deposition takes place up to the desired layer thickness. Subsequently, a layer system may optionally be constructed using galvanic baths.

embodiment

A cleaned substrate made of a capacitor ceramic Ef 750 or U 150 is irradiated by an Hd-YAG laser with an average power of 3.6 ¥, a pulse repetition frequency of 15 Hz partially with an xy-coordinate table speed of 30 mm / s. The M _o denblende has a diameter of 1.52 mm, the focal length of the lens is 75 mm.

Upon irradiation, an activated trace of 30 is created on the surface, around track width.

This activated lane is coated in a chemically reductive 2Jikkelbad (eg., According to GDR Patent 157 773) with the desired layer thickness of 2, to Ii P.

Claims (1)

- 5 claim 1. Laser activation of dielectric surfaces for partial chemical-reduction metal deposition, characterized in that the partial activation is effected by a partially incident on the surface of the laser beam, a change in the chemical potential of the surface and a necessary for the subsequent taking place in a second process chemically-reducing metal deposition catalytic Activity achieved.