# US 7,611,569 B2 · Electroless copper compositions

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- Number: US 7,611,569 B2
- Document ID: US7611569B2
- Status: Granted
- Kind: B2
- Application number: 11/825,379
- Filed: 2007-07-06
- Published: 2008-02-14
- Granted: 2009-11-03
- Earliest claimed: 2006-07-07
- Assignees: Rohm and Haas Electronic Materials LLC
- Inventors: Mark A. Poole; Andrew J. Cobley; Amrik Singh; Deborah V. Hirst
- Web page: https://patentgrep.com/patent/US7611569B2

## CPC

- C23C 18/40: using reducing agents
- H05K 3/422: {characterised by electroless plating method; pretreatment therefor}
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

Electroless copper and copper alloys plating baths are disclosed. The electroless baths are formaldehyde free and are environmentally friendly. The electroless baths are stable and deposit a bright or copper alloy on substrates.

## Claims

### Claim 1

A composition comprising one or more sources of copper ions, one or more chelating agents selected from the group consisting of hydantoin and hydantoin derivatives and 20 g/L to 80 g/L of one or more reducing agents selected from the group consisting of fructose esters, the composition is formaldehyde free.

### Claim 2 (depends on 1)

The composition of claim 1, wherein the chelating agents range from 20 g/L to 150 g/L.

### Claim 3 (depends on 1)

The composition of claim 1, wherein the hydantoin derivatives are selected from the group consisting of 1-methylhydantoin, 1,3-dimethylhydantoin, 5,5-dimethylhydantoin and allantoin.

### Claim 4 (depends on 1)

The composition of claim 1, wherein the fructose esters are selected from the group consisting of fructose hexanoate, fructose heptanoate and fructose pentanoate.

### Claim 5 (depends on 1)

The composition of claim 1, further comprising one or more additional additives.

### Claim 6

A method comprising:
a) providing a substrate; and
b) electrolessly depositing copper on the substrate with an electroless copper composition comprising one or more sources of copper ions, one or more chelating agents selected from the group consisting of hydantoin and hydantoin derivatives and 20 g/L to 80 g/L of one or more reducing agents selected from the group consisting of fructose esters, the electroless copper composition is formaldehyde free.

### Claim 7

A method comprising:
a) providing a printed wiring board comprising a plurality of through-holes;
b) desmearing the through-holes; and
c) depositing copper on walls of the through-holes with an electroless copper bath comprising one or more sources of copper ions, one or more chelating agents selected from the group consisting of hydantoin and hydantoin derivatives and 20 g/L to 80 g/L of one or more reducing agents selected from the group consisting of fructose esters, the electroless copper bath is formaldehyde free.

### Claim 8 (depends on 7)

The method of claim 7, wherein the electroless copper composition further comprises one or more additional additives.