Methods and Apparatus for bump-on-trace Chip Packaging

Abstract

Methods and apparatus for a solder mask trench used in a bump-on-trace (BOT) structure to form a semiconductor package are disclosed. A solder mask layer is formed on a trace and on a substrate. An opening of the solder mask layer, called a solder mask trench, is formed to expose the trace on the substrate. The solder mask trench has a width about a size of a diameter of a solder bump. A solder bump is landed directly on the exposed trace to connect a chip to the trace by an interconnect. With the formation of the solder mask trench, the trace exposed in the solder mask trench have a better grab force, which reduces the trace peeling failure for the semiconductor package. A plurality of solder mask trench rings may be formed in a package.

Dependencies are inferred from the claim text.