SU387542A1 - ELIMINATOR FOR ELECTORAL Etching of TIN FILMS - Google Patents

Description

one

The invention relates to the production technology of radio components and can be used in the manufacture of hybrid film circuits.

The known etchant is for selective etching of tin films deposited on polymeric material and protected by a layer of photoresist in accordance with the obtained pattern, containing a mixture of nitric, hydrochloric and acetic acids with water.

However, etching of tin films in concentrated acids leads to intense destruction of both the polymer material and the photoresist, which protects the tin films during the etching process.

The aim of the invention is to preserve the polymer material and the photoresist during the etching process.

For this purpose, sodium nitrate and glycerin are additionally introduced into the trap at the following ratio of components, in weight. 7о: Nitric acid (sp. Weight 1,41) 3-6 Sola acid (sp. Weight 1,18) 5-9 Acetic acid (ice) 20-31 Water (distilled) 10-19

Sodium Nitrate3-6

Glycerin Else

The presence of glycerol in the proposed etcher eliminates the etching of the polymeric material by the etchant during the selective etching of m-chip circuit elements made of tin films, for example, the upper plates: K film capacitors, which allows them to be made by photolithography without disturbing the polymer layer.

Sodium nitrate, the E composition of the etchant, increases the stability of the photoresist during etching of the tin film without prior heat treatment (tanning) of the photoresist at high temperatures. The ratio of acids is chosen in such a way as to get high speed.

etching (6000 A / min at 20 ° C) with minimal side etching.

The invention is illustrated by the following example.

Layers are sprayed onto the sieve metal substrate.

about

Nickel thickness 4000-6000 A. Then using the method of photolithography make the lower plates of acid capacitors. Silicone-based polymer is sprayed onto the bottom plates of nickel in a glowing discharge during the polymerization of the hectomethyl disiloxo monomer

: at a thickness of 5000 A. Then, 6000 A thickness of tin is sprayed onto the polymer film and the OP-334 photoresist is applied on a centrifuge at a rotational speed of 1200-1400 rpm. Dried at 95 ° C for 15-20 minutes, exposed and developed.

The substrate prepared in this way

placed in an etchant of the following composition:

Nitric acid 1.41 beats. weight 4 ml

Sol acid: 1.48 beats. weight 7 ml

Acetic acid (ice) 23 ml

Sodium nitrate5 gr

Glycerin47 ml

Water (distilled) 14 ml

and corrode the design of the upper plates

film capacitors.

The end of the etching process is fixed visually. The etching rate of tin films in an etchant of a reduced composition is

about

6000 A / min at a temperature of -20 ° C. After washing the substrate in distilled water, the photoresist is removed in acetone, dioxane or other organic solvents.

Subject invention

An etchant for selectively etching tin films deposited on a polymeric material and protected by a layer of photoresist in accordance with the p-ian obtained, containing a mixture of nitric, hydrochloric and acetic acids with water, characterized in that in order to preserve the photoresist polymer material in the process of etching, the etchant additionally contains sodium nitrate and glycerin, and the following ratio of components, in weight. %

Nitric acid (sp. Weight 1,41) 3-6. Hydrochloric acid (sp. Weight 1,18) 5-9 Acetic acid (ice) 20-31 Water (distilled) 10-19

Sodium Nitrate3-6

Glycerol

Rest