SU1756311A1 - Method of metallization of ceramics - Google Patents

Abstract

The mixture contains, by weight,%: high-alumina cement 5,0-15.0, lithographic stone - the rest. At the same time, it contains a lithographic stone with a fraction of 200-100 microns and no more than 100 microns in a 1: 1 ratio. Polycrystalline diamond yield 62–82 carag. 1 tab., 1 Il.

Description

The invention relates to a method for the metallization of the inner surface of small-diameter holes in printed circuit boards and ceramic parts and can be used in the electronic, electronic and instrument-making industry.

A known method of chemical metallization of the inner surfaces of small-diameter holes in printed circuit boards made of ceramics (for example, polycor, 22XC ceramics, stood, various grades of cellars, etc.), which means that the metallized surface of the ceramics is sensitized with a solution of tin chloride, and then treated in solution palladium chloride, and after the formation of an electrically conductive coating, a layer of copper, nickel, or another (of a metal of the required thickness

However, the method does not have selectivity and therefore all surfaces treated with tin chloride and tin chloride and palladium chloride are metallized, including the surfaces of the suspension devices. This complicates the process.

forming a metallization coating increases the waste of materials and makes it difficult to automate the process. The process is characterized by increased energy consumption and laboriousness in the use of c and c, that it is necessary to remove the metallization coating from the areas that are not subject to metallization by grinding, and subsequent polishing of the polished areas is necessary to obtain a high surface resistivity. This method is applicable only for manual maintenance and a small production program.

There is also known a method of metallization of the inner walls of the holes in the ceramic parts, which consists in immersing the part in a metallization paste of refractory metals and their oxides, holding it until the holes are completely filled, removing the excess paste and pressing the paste into hydrogen. temperature 1670-1750 K.

The disadvantages of the method include the imperfection of the method of applying paste on

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inner-walls of small-diameter holes, difficulty of half-covering the same tola, irrational paste consumption due to the fact that at the same time other surfaces are metallized, the coating from which after burning is removed by machining (grinding, polishing), i.e. the method does not have selectivity; paste is burned in an explosive atmosphere (hydrogen) at a high temperature of 1670-1750 K.

The closest to the technical essence is the method of metalpization of ceramics by spraying a vacuum of 6.65-10 3-1.33-10 3 Pa (Torr) palladium alloy containing 20-70% of Co, and to improve the adhesion of the coating to ceramics in the metallization a layer of 3-20% chromium, manganese or titanium is introduced. The technological process of metallization consists of the following operations, treatment of the metallized surface by ion bombardment in a glow discharge at a pressure of 10 Pa (8 -10 2 Torr), deposition of an active metal (chromium, manganese) in a vacuum of 6.65, 33-103 Pa (5 -U -1-10 5 Torr) at an evaporator temperature of 1275 K (1100 ° C), then deposition of a palladium-cobalt alloy at an evaporator temperature of 1525-1575 K (1250-1300 ° C) Evaporation of the deposited metals is carried out from a tungsten boat. .

The disadvantages of the discussed method of metallization of ceramics are its multi-stage nature, caused by the need to carry out ionic cleaning, deposition of the active metal and palladium alloy at different pressures in the working volume and at different evaporator temperatures,

In addition, the method does not allow to obtain stable results when metallizing curved surfaces and internal surfaces of the holes.

The aim of the invention is to simplify the metallization of the inner surfaces of small-diameter holes, increase the adhesion of the coating to the substrate and reduce the energy intensity of

The goal is achieved by the fact that in the process of metallization of ceramics, the assembly from a ceramic part and a target made on the basis of palladium- and titanium-containing components is heated in vacuum

 to a temperature of 500-600 K and additionally locally heat the sputtered target with several laser pulses with a pulse energy of 42-75 J, and palladium chloride and titanium hydride are used as target components at the following ratio, mass%: palladium chloride 74-82% ; titanium hydride the rest,

Under the action of a pulsed laser

The radiation temperature of the target at the site of irradiation quickly rises above 800 K, the target material is sprayed, while at rest the palladium chloride decomposes into palladium and chlorine, and the titanium hydride into titanium and

hydrogen. Palladium and titanium vapors are condensed on the metallized surface of ceramics, chlorine gas and hydrogen, and the gaseous products of their interaction with each other and with the substances adsorbed on the metallized surface are pumped out of the metallization zone by a vacuum pump. The coating of the desired thickness is obtained by exposing the target to an appropriate number of pulses of laser radiation,

Simplification of the technology of metallization of the curved surfaces of ceramic parts and the inner surface of the holes and reducing the energy intensity of the method

A single-stage process is achieved by using a pulsed laser to spray the target and locally heat the decomposing palladium and titanium coder, compounds to

decomposition temperatures, the absence of any auxiliary materials in the metallization process. The method allows one to automate the metallization process of ceramic parts with a large number of holes using a two-coordinate table and a microprocessor with an appropriate program.

An increase in the adhesion of the metallization coating to the substrate is achieved by using palladium chloride and titanium hydride as a sputtered material, which, when locally heated to temperatures above 800 K, are decomposed by pulsed laser radiation into palladium and chlorine, titanium and hydrogen, respectively. Chlorine and hydrogen at the time of decomposition are in the atomic state and therefore actively interact with each other, forming gaseous hydrogen chloride,

and with substances adsorbed on the surface to be metallized (oxygen, nitrogen, carbon dioxide, etc.), contributing to the additional cleaning of the surface to be metallized. Chlorine gas and hydrogen and

the products of their interaction (water vapor, hydrogen chloride, methane, etc.) are pumped out of the metallization zone by a vacuum system. Metals (palladium and titanium) are condensed in the relatively cold

ceramic surfaces to form a metallization coating.

Adhesion is enhanced by the use of titanium as one of the coating components. Titanium at a temperature of 500-600 K interacts with alumina, which is one of the main components of the above-mentioned ceramic materials, with the formation of a system of solid solutions of the components of ceramics (aluminum and oxygen) with titanium and palladium. In addition, when the substrate temperature is 500-600 K after deposition of titanium and palladium, they diffuse along the grain boundaries and structural inhomogeneities of the grains (dislocations, vacancies) of ceramics. As a result of the chemical effect of the deposited metal with ceramics and its diffusion along the grain boundaries and structural inhomogeneities of the adhesion of the titanium to the palladium coating, it is comparable with the strength of the substrate material under stretching and shear.

The drawing shows a scheme that implements the method.

Example. Detail 1 of the floor and bark with a thickness of 1.2 mm with a hole 2 of small diameter (for example, 0.8 mm) is put in contact with the target 3 pressed from a mixture of palladium chloride and titanium hydride (74-82 wt.% PdCl, 26-18 wt.% Tihte). The assembly is installed in the fixing device, placed inside the heater 8, which is located in the vacuum chamber 4 (Fig. 1). The laser beam 6 is focused by lens 7 through the window 5 and the metallized hole 2 on the surface of the target 3. The pressure in the vacuum chamber decreases to Pa and then the heater 8 is turned on, which heats the assembly to a temperature of 500-600 K. After reaching this temperature several energy pulses of the laser 42-75 J pulse is pulverizing the target. The sprayed palladium chloride and titanium hydride are heated to temperatures above 800 K. At this temperature, palladium chloride decomposes into palladium and chlorine, and titanium hydride into titanium and hydrogen. Chlorine gas and hydrogen, as well as the products of their interaction with each other with adsorbed substances, are sucked off by a vacuum system. Metals (palladium and titanium) are condensed on the inner surface of the hole.

To obtain an equilibrium structure of the coating with a low level of internal stresses at the surface of the coating-ceramic interface, it is recommended to conduct 5 homogenizing annealing at a temperature of 850-950 K in the same vacuum, J

The results of the experiments reduce the table.

The proposed method, compared with the prototype, has less laboriousness (the proposed method allows obtaining a titanium coating with a thickness of 1-3 µm in one operation (in prototype -3), the method allows automating the process of unavailable surfaces, in particular, small-diameter holes in ceramic plates and parts), are 1.5 to 2 times less power than the prototype method. The proposed method makes it possible to obtain coatings with high adhesion to inorganic dielectrics due to the chemical interaction of the titanopalladium alloy with aluminum oxide and the diffusion of metal 5 of the coating along the grain boundaries to structural inhomogeneities of the substrate material, as well as a metal coating ionic coating with a satisfactory capacity of low and media N heat solids 0 based on tin, silver and copper,

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Claims (1)

Invention Formula The method of metallization of ceramics, including joint heating in vacuum of Pa of ceramics and a sputtered target based on palladium- and titanium-containing components to a temperature above the sublimation temperature of the target, differs from the fact that, in order to simplify the metallization of the internal hole surfaces of small diameter, the energy intensity is reduced , the target has a contact inner surface of the hole, together they heat up to 500-600 K, and the additional heating of the target is carried out locally by pulsed radiation of a laser with an energy in a pulse of 42 75 J, and palladium chloride and titanium hydride are used as components of the subliming target in the following ratio, wt.%: Palladium chloride 74-82 Hydride, titanium Else  The results were obtained when a sample was tested in the form of a rod, inserted into the metallized hole with silver-based solder (PSr 50) at a temperature of 1140 K.