Etching Solutions

An etching solution for silver or silver alloy comprising at least one ammonium compound represented by the formula (1), (2) or (3) below and an oxidant:

• each of R1, R2, R3, R4, R5 and R6 is, independently, selected from hydrogen;
• substituted or unsubstituted C1-C30 aliphatic alkyl, alicyclic alkyl, aryl or aralkyl;
• a polymer compound;
• a heterocyclic compound;
• and derivatives thereof and R1 and R2 or R4 and R5 may be connected to form a ring.