Acid bath for copper plating and process with the use of this combination
AssigneeAtotech Deutschland GmbH
InventorsWolfgang Dahms, Horst Westphal
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Abstract
An aqueous acid bath for galvanic precipitation of copper is disclosed. The copper plating composition comprises at least one polymer phenazonium compound and .beta.-naphtholalkoxylate. A method for using such a bath for deposition of copper coatings is also disclosed. The resultant copper coatings are smooth and bright with substantially no fine roughness or pitting.
Claims30
An aqueous acid bath for galvanic deposition of bright, and smooth copper coatings which avoids fine pitting comprising:
- a) a .beta.-naphtholalkoxylate of the formula ##STR2## wherein n=0-50, m=0-50 and n+m>3. b) at least one polymer phenazonium compound;
- c) copper sulfate;
- d) one or more of an organic nitrogen-free thiocompound;
- and
- e) polyethylene glycol present in a concentration from 0.05 to 5 g/liter.
An aqueous acid bath for galvanic deposition of bright and smooth copper coatings which avoids fine pitting comprising:
- a) a .beta.-naphtholalkoxylate of the formula ##STR3## wherein n=0-50, m=0-50 and n+m=>3;
- b) at least one polymer phenazonium compound;
- c) copper sulfate;
- d) one or more of an organic nitrogen-free thiocompound;
- and
- e) at least one oxygen-containing high-molecular compound present in a concentration from 0.005 to 5 g/liter.
A process for galvanic deposition of bright and smooth copper coatings which avoids fine pitting, comprising the steps of:
- a) providing an electrolyte bath comprising an aqueous acid bath including:
- i) a .beta.-naphtholalkoxylate of the formula ##STR4## wherein n=0-50, m=0-50 and n+m>3;
- ii) at least one polymer phenazonium compound;
- iii) copper sulfate;
- iv) one or more of an organic nitrogen-free thiocompound;
- and
- v) at least one oxygen-containing high-molecular compound present in a concentration from 0.005 to 5 g/liter;
- and
- b) applying a cathodic current density of from about 0.5 to about 12 A/dm.sup.2.
A process for galvanic deposition of bright and smooth copper coatings which avoids fine pitting, comprising the steps of:
- a) providing an electrolyte bath having a pH range comprising an aqueous acid bath including:
- i) a .beta.-naphtholalkoxylate of the formula ##STR5## wherein n=0-50, m0-50 and n+m>3;
- ii) at least one polymer phenazonium compound;
- iii) copper sulfate;
- iv) one or more of an organic nitrogen-free thiocompound;
- and
- v) polyethylene glycol in a concentration from 0.05 to 5.0 g/liter;
- b) applying a cathodic current density of from about 0.5 to about 12 A/dm.sup.2 ;
- c) maintaining a temperature of the bath of from 15.degree. C. to 45.degree. C.;
- and
- d) maintaining the pH of the bath at a value of 1 or less.
Dependencies are inferred from the claim text.