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High-selective chemical metallization of laser draught on ceramic substrates and crystals

– High-selective metallization of laser draught on ceramics and crystals.

– Technological process allows to apply nickel, cobalt, manganese, chrome, tungsten, molybdenum, indium, gallium, palladium, platinum, copper, silver, gold, tin, cadmium, iron selectively with chemical method on the surface irradiated with laser.

– Metallization may be performed as monolith with set width, and with the layers in any priority as alloys on mentioned metals and alloys dopes with phosphorus, boron, arsenic, carbon, silicon.

All the abovementioned is applied on oxides, carbides, nitrides of aluminum, boron, manganese, calcium, silicon and on natural stones – ruby, sapphire, diamond, emerald and others.

Field of application: electronics, medical devices, jewelry production.

Brief description of the first complex program in manufacturing of switching cards for surface mounting.

As usual ceramic substrates on the basis of alumina, pyroceram, enameling steel are used. Switching draught by itself is received by metallizing the substrates according to film or thick-film technology using the method of photolithographic processing.

This technologies did not change over thirty years although the weight of technical limitations restrains the process of development of micro and optoelectronics on the background of pronounced achievements in the elementary base.

Naturally the attempts to compact the commutation took place: using of x-ray and electric lithography, search of new thermally conductive dielectric substrates.

However practically the width of conductive material and backlash clearance between them did not succeed to be less then 100 mkm.

At that it is achieved by the methods of thin-film technology.

And using of already known today ceramics on the basis of A1N is not practical as it is polished badly.

It resulted in critical situation.

We received new materials for substrates: nitride aluminium, nitride silicon, silicon carbide, rubies, leucosapphires, diamond ceramics that has unique combination of qualities that is high thermal conductivity, good dielectric characteristics, high mechanical durability, low coefficient of thermal linear expansion.

There is no technology of selective metallization that would correspond its level.

We suggest new alternative method of high selective metallization of practically any hard materials, including new ones indicated above.

The work developed in two stages.

The first one was based on the effect of electrical conductivity acquisition by the surface of the materials under the influence of laser emission.

They include such incongruently melting materials as A1N, Si3N4, SiC, that decomposer during melting with separation of conductive phase, and the materials in which the conductive phase appears under the influence of laser emission due to polymorphic transformations.

This effect was used to create correspondent draught on the surface of dielectric substrate. To enforce such conducting materials, that is to increase its electrical conductivity the technology of selective nickel disposition on the laser draught was developed.

Such works performed at the beginning of nineties in America, Japan and by us. We have correspondent patents and author’s certificates.

The disadvantages of the new method were as follows:

– necessity of special materials;

– dependence of electrical conductivity of combined conducting material (conductive phase that appears after laser emission and the cover of nickel) from the properties of such conductive phase, in particular of the value of its electrical resistance.

Taking into consideration certain material nonhomogeneity and variation of properties from one plate to another in such parameters as density and sponginess it had an influence on reproductibility of the creation process of switching cards with defined properties.

Today we offer new method of selective metallization of practically any solid body where the instrument for previous activation and creation of the necessary draught is laser beam.

At this there is no necessity in initiation of conductive phase or any special chemical substance during laser processing.

Previous change of aggregate state that results in disorderly or neglected links is enough to activate it.

Roughly speaking, it is necessary to refresh the surface, that’s all.

To deposit the metal on the surface of substrate that is activated by laser beam we need to sink the substrate to the correspondent solution and to keep it under certain temperature.

Therefore nickel, gold, silver, indium, gallium, molybdenum, tungsten and other metals may deposit in such way.

So, we offer combined technology of receiving of superdense transparent and opaque double-sided switching cards with three-dimensional draught for surface mounting of high heat-conducting ceramics and crystals.

Even the first steps of new technology using amaze by its unique possibilities and by perspectives of its usage.

Currently we produce the cards for miniature optoelectronic commutation switch, for example, of a size of 52x52x1,5 mm made from nitride aluminum leucosapphire and ruby furnished with film-type refrigerator on its ends that maintains the temperature of the plate 4.5 degrees lower than environment temperature.

On the photo you can see two surfaces of it. Laser beam provided basic openings with diameter of 2.5 mm, 255 openings with diameter of 750 mkm in a circumferential direction for golden insertions patching and 255 openings with diameter of 120 mkm in center which are to provide direct contact between the crystal of GaAs (gallium arsenide) and the crystal of Si (silicon).

Conductive strips are of 60 mkm width with backlash is 40 mkm. And it is not a limit.

Photos of samples.

We reached the result when the width of the strip is 40 mkm, and backlash between it is 20 mkm.

At that salting resistance is less then 0,025 OM\sq.

The resistance of isolation between it is more then 10 Om.

Parasitic capacitance of tenth of pF under dielectric permeability of substrate material is 10-11.

Using of high heat-conducting substrate allows to disperse and to relieve the heat along the substrate from silicon crystal of 10W and not to endanger the crystal of gallium arsenide.

And now there are few example of abovementioned technology use:

  1. Equipment of superhigh frequency, heat-conducting crystals, for instance rubies with heat conduction of 250 W\mK with special separation of metallization.
  2. Optoelectronic separations for special technique and for computers of new generation.
  3. Crystal holders for high-powered frameless crystals (special equipment, household appliance)
  4. Jeweler’s industry (to write and paint with gold, silver on any stone of any size), speed processing of diamonds.
  5. Medical equipment:micro-heaters for blood stop during surgery operations;ceramic scalpels with heater;dental ceramic knife to work with modest materials, plasticizer for tooth filling.

Refrigerators (coolers) of purpose appointment, portative refrigerators without Freon including those of household purpose. Conditioners of new generation.

Problem of contacts is a problem of microelectronics.

In most of cases expensive vacuum technologies are used.

New technology allows realization of surface metallization of many solid materials practically in home conditions.

Laser, thermostat and special solution is everything that you need.

We can only add the following:

– The cards proposed by us can be used in computers or laptops, completely eliminating heating, including heating from both sides, as well as the occurrence of steam and water.

The cards proposed by us can be used as refrigerators (coolers) of designated purpose, portable refrigerators without Freon, including those of household purpose, as well as air-conditioners of a new generation.

We can offer the production technology of three-dimensional switching cards with guaranteed stability of operation of compacted electrical mounting with energy load of about five hundred watts per square centimeter, with the intensity up to one kilovolt per millimeter, by using of ceramics with heat conduction coefficient of not less than one hundred and twenty watts per meter degree.

If you are interested – we will provide additional information and designer’s supervision over implementation of the technology.

p.s. We expect proposals for mutually beneficial cooperation

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