Lead-frames copper oxidation effect for a QFN package delamination improvement

A quad flat no-lead (QFN) package delamination improvement and its related lead-frame (LF) copper oxidation effect were studied. Pudding mold adhesion testing method was utilized to determine the epoxy molding compound (EMC)/LF interfacial adhesion performance, chemical composition change including cupric oxide (CuO, Cu
⁺⁺
) and cuprous oxide (Cu
₂
O, Cu
⁺
) on LF surface oxidation structure was identified by Auger electron spectroscopy (AES). Experimental results have shown that higher CuO/Cu
₂
O ratio (Cu
⁺⁺
/Cu
⁺
> 1) have a good adhesion characterization for different oxidizing observation, moreover, AES depth profile analysis have supported that the demonstration much CuO content to reduction is verified an important adhesion improvement after plasma clean process. Back-end plasma clean conditions such as plasma time, slot/un-lot magazine type, and H
₂
/Ar mixing gas flow rate in a QFN package production for enhancing adhesion characterization were studied, moreover, a package delamination improvement was obtained by plasma clean conditions tuning.