Black Chromium as a Solder Dam
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-10
In the manufacturing of substrates for the mounting of integrated circuit chips, top surface metallization is applied to the substrate. Conventionally this metallization includes successively depositing a bottom layer of Cr, an intermediate layer of Cu, and a top layer of Cr. When the chip or chips are to be soldered by flip-chip bonding techniques, the top layer of Cr is removed by etching where the solder connections are to take place and is left in the remaining areas to act as a solder dam. Certain problems such as etch undercutting and striping have been encountered in removing the top layer of Cr in the desired areas.