Treating laminates

Claim 2

An aqueous composition for treating a laminate for a printed circuit board, the composition comprising a wetting agent having a positively charged quaternary nitrogen atom and a reducing agent compatible with the wetting agent.

Claim 3

A composition as claimed in claim 1 wherein the reducing agent is: (a) hydroxyalmine or a salt thereof, and/or (b) oxalic acid or a salt thereof.

Claim 4

A composition as claimed in claim 1 or 2 wherein the reducing agent is hydroxylamine sulphate, hydroxylamine hydrohalide, sodium oxalate and/or potassium oxalate.

Claim 5

A composition as claimed in claim 1, 2 or 3 wherein the wetting agent has the formula wherein each of R 1 , R 2 , R 3 and R 4 independently represents a C 1 to C 20 alkyl group, a C 6 or C 10 aryl or a C 7 to C 30 arylalkyl or alkylaryl group, each optionally substituted with a group -OR 5 , -NHR 5 R 6 , where each of R 5 and R 6 independently represents a hydrogen atom or a C 1 to C 20 alkyl group; and X n - represents a compatible anion of acidity n, where n is an integer from 1 to 4.

Claim 6

A composition as claimed in any one of claims 1 to 4 which also comprises a complexing agent.

Claim 7

A composition as claimed in claim 5 wherein the complexing agent is a soluble amine, alkanolamine, amine carboxylic acid, hydroxycarboxylic acid, amine phosphoric acid and/or tetraethylene pentamine.

Claim 8

A composition as claimed in any one of claims 1 to 6 which also comprises a nonionic surfactant.

Claim 11

-9. A method of preparing a drilled multilayer laminate for a printed circuit board for being receptive to the deposit of copper, the method comprising the steps of: (a) treating the laminate with permanganate to de-smear the drilled hole(s), (b) contacting the laminate with an aqueous composition of a wetting agent having a positively charged quaternary nitrogen atom and a reducing agent compatible with the wetting agent, (c) optionally mildly etching an external copper layer of the laminate to render its adhesive qualities suitable for the deposition of electroless copper thereon, (d) contacting the laminate with an acidic solution, (e) contacting the laminate with a composition for depositing catalyst for rendering the laminate's surfaces catalytic to the deposit of copper on them and (f) optionally further contacting the laminate with an accelerator composition.

Claim 12

-9. A method of preparing a drilled multilayer laminate for a printed circuit board for being receptive to the deposit of copper, the method comprising the steps of: (a) treating the laminate with permanganate to de-smear the drilled hole(s), (b) contacting the laminate with an aqueous composition of a wetting agent having a positively charged quaternary nitrogen atom and a reducing agent compatible with the wetting agent, (c) optionally mildly etching an external copper layer of the laminate to render its adhesive qualities suitable for the deposition of electroless copper thereon, (d) contacting the laminate with an acidic solution, (e) contacting the laminate with a composition for depositing catalyst for rendering the laminate's surfaces catalytic to the deposit of copper on them and (f) optionally further contacting the laminate with an accelerator composition.

Claim 13

.A method as claimed in claim 9 wherein the permanganate is an alkali solution of a permanganate salt and the accelerator composition is fluoboric acid.