The solution for chemical copper plating

 

(57) Abstract:

The invention relates to the field of production of copper coatings from solutions by the method of chemical recovery and can be used for metallization of printed circuit boards in electronics. The solution contains copper sulfate, petitou 10,0-15,0 g/l; potassium-sodium tartrate 50,0-60,0 g/l; Nickel chloride 2,0-4,0 g/l; sodium carbonate 2,0-4,0 g/l; sodium hydroxide 13,0-15,0 g/l, formalin (37%) of 10.0-15.0 ml/l; the thiourea - 0,001-0,003 g/l, potassium genesisintermedia 0.03-0.05 g/l and distilled water to 1 L. the Technical result of the chemical copper plating, the providing quality, necessary for the occurrence of subsequent electrolytic deposition processes, the stability of the solution, the reduction of environmental pollution, consumption of reagents and labor due to reusable solution. table 2.

The invention relates to the field of production of copper coatings from solutions by the method of chemical recovery and can be used for metallization of printed circuit boards in electronics.

For analog adopted tartrates the copper plating solution used in the manufacture of printed circuit boards composition [1], containing copper sulfate g/l; sodium hydroxide is 13.0-15.0 g/l; formalin (37%) - 10.0 to 15.0 ml/l; sodium Chernovetskiy - 0,001-0,002 g/l

Recovered from this solution copper fragile, dark, rapidly oxidize in air. The reaction rate of recovery of copper ions is insufficient, the solution metastabile in time and therefore it is impossible to obtain high quality coatings both chemical and electrolytic copper.

The closest in technical essence of the prototype - is tartrate solution chemical copper plating containing a two-component stabilizer: the thiourea - 0,001-0,003 g/l and sodium Chernovetskiy - 0.0005 g/l [2].

The solution is compared to similar more stable, however, due to high initial reaction rate caused by the simultaneous presence of two serosoderjaschei components that contribute to intensive production of hydrogen, copper coatings are produced porous and heterogeneous, making it difficult to obtain further dense and elastic electrolytic precipitation of copper.

The objective of the invention is the obtaining of chemical copper coating providing quality, necessary for the occurrence of subsequent electrolytic deposition processes.

The task is lead as a stabilizer potassium genesisintermedia in the following ratio of components: copper sulfate, pativedha - 10,0-15,0 g/l; potassium-sodium tartrate - 50,0-60,0 g/l; Nickel chloride - 2,0-4,0 g/l; sodium carbonate - 2,0-4,0 g/l; sodium hydroxide - 13,0-15,0 g/l; formalin (37%) - 10.0 to 15.0 ml/l; thiourea - 0,001-0,003 g/l; potassium genesisintermedia - 0.03-0.05 g/L.

Comparison with the prototype shows that the claimed composition chemical copper plating is characterized by the fact that as a complex stabilizing additives in the solution together with thiourea injected potassium genesisintermedia in the amount of 0.03-0.05 g/L. Simultaneous presence in the solution of chemical copper plating thiourea and potassium relatoseroticos allows to obtain bright, dense and uniform copper coating, characterized by plasticity and melkochristallicescoy. The copper plating solution of the composition is stable. In the process of copper plating is not observed spontaneous recovery of copper in volume during the long term solution. The quality of the precipitated copper provides further leaking electrolytic deposition processes in accordance with the technological process.

Thus, the technical result of the invention is expressed in the following:

improving the quality of chemically deposited layer of copper which was mentioned);

increases the stability of the solution due to the lack of recovery of copper in solution due to the formation of a stable complex compounds of the components of the additive ions with monovalent copper;

decreases the degree of environmental pollution, consumption of reagents and labor costs through reusable solution.

A comparison of the proposed technical solutions to the prototype allows you to set the criterion of “novelty.”

Due to the fact that obtaining copper coatings from solutions by the method of chemical recovery as an intermediate conductive layer is widely used in radio production for metallization of printed circuit boards, the claimed technical solution meets the criterion of “industrial applicability”.

The main characteristics of the solutions unique and inventive composition are presented in table 1.

The preparation of the claimed solution of the chemical copper plating is performed as follows.

The estimated amount of copper sulfate and douglasthe Nickel dissolved in half of the required amount of water. In the other half dissolve the hydroxide of sodium, potassium-sodium tartrate and sodium carbonate.field level solution with distilled water to 1 L. The solution is filtered and check the value of pH, which can vary from the 12.6 to 12.8. Per day to work in the freshly prepared solution is injected stabilizer - complex Supplement. The stabilizer is prepared in the form of concentrated aqueous solutions: 1 g of thiourea are dissolved in 1 l of distilled water, 10 g of potassium relatoseroticos dissolved in 1 l of distilled water. Each component of the additive is injected separately. Formalin is injected before starting work.

Before carrying out the process of chemical copper plating samples of foil dielectric is subjected to the preparation by standard methods according to GOST 23770-79, then spend the deposition process at 25 for 30 min at a density of loading of 1.5-2 DM2/l

The choice of the optimal allowable concentration of potassium relatoseroticos defined in examples 1-5. The results are presented in table 2.

Example 1

Chemical copper plating is carried out in a solution containing copper sulfate petitou - 15.0 g/l; potassium-sodium tartrate - 60,0 g/l; Nickel chloride - 4.0 g/l; sodium carbonate - 4.0 g/l; sodium hydroxide - 15.0 g/l; formalin (37%) - 15.0 ml/l; the thiourea - 0.001 g/l; potassium genesisintermedia - 0.01 g/L.

the pH of the solution, Nedeli. The precipitate dark pink, mixed.

Example 2

Chemical copper plating is carried out in solution composition similar to example 1. The composition of the additive, g/l: thiourea 0,001; potassium relatoseroticos 0,03.

The deposition rate is 1.5 μm/h, the solution is stable, floor light pink, solid, tight.

Example 3

Chemical copper plating is carried out in solution composition similar to example 1. The composition of the additive, g/l: thiourea 0,001; potassium relatoseroticos 0,04.

The deposition rate of 1.3 μm/h, the solution is stable, floor light pink solid.

Example 4

Chemical copper plating is carried out in solution composition similar to example 1. The composition of the additive, g/l: thiourea 0,001; potassium relatoseroticos 0,05.

The deposition rate of 0.9 μm/h, the solution is stable, floor light pink color, uniform.

Example 5

Chemical copper plating is carried out in solution composition similar to example 1. The composition of the additive, g/l: thiourea 0,001; potassium relatoseroticos 0,07.

The deposition rate of 0.7 μm/h, the solution is stable, but the copper deposition is slowed down, cover pink with dark stripes.

From anae supplements from 0.03 to 0.05 g/l of potassium relatoseroticos, allow you to get a thick copper coating light pink color with clean sediment that 98.9-99.2%, and guaranteeing the conditions of quality electrolytic deposition of copper. The solution is characterized by the almost complete absence of volumetric recovery of copper, which provides high stability in operation without changing the properties and conditions of its use for at least 6 months.

Changes in the concentration of potassium relatoseroticos downward (less than 0.03 g/l) or increase (greater than 0.05 g/l) leads to the formation of defective coating (examples 1 and 5).

Sources of information:

1. GOST 23770-79. Card printing.

2. Petrova, Etc., Chemical coating / Soros educational journal, No. 11, pp. 57-62, 2000.

The solution for chemical copper plating of printed circuit boards containing copper sulfate petitou, potassium-sodium tartrate, Nickel chloride, sodium carbonate, sodium hydroxide, formaldehyde, thiourea, characterized in that for improving the quality of chemically deposited copper coatings it additionally contains potassium genesisintermedia in the following ratio of components, g/l:

Copper sulfate pativedha 10,0-15,0

Potassium-sodium winnock"ptx2">Formalin (37%), ml/l 10,0-15,0

Thiourea 0,001-0,003

Potassium genesisintermedia 0,03-0,05

Distilled water To 1 l

 

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