Abstract: Tin or tin alloy plating liquid with a sufficient plated deposit can be formed in the opening without causing burns on the plated film surface or abnormal deposits, and which has a good via filling effect. When a specific ?, ?-unsaturated carbonyl compound is added into the tin or tin alloy plating liquid, the plating liquid with good via filling performance can be obtained, and the deposit which is substantially free of voids and burns or abnormal deposits on the deposit surface are reduced.

Abstract: The present invention relates to a stable palladium ion catalyst aqueous solution for electroless metal plating that does not use boric acid and can be used stably over a wide pH range. The catalyst solution for electroless plating of the present invention contains palladium ion, palladium ion complexing agent, and a specific amine compound and is alkaline.

Abstract: Tin or tin alloy plating liquid with a sufficient plated deposit can be formed in the opening without causing burns on the plated film surface or abnormal deposits, and which has a good via filling effect. When a specific ?,?-unsaturated carbonyl compound is added into the tin or tin alloy plating liquid, the plating liquid with good via filling performance can be obtained, and the deposit which is substantially free of voids and burns or abnormal deposits on the deposit surface are reduced.