Dummy Pillars Maintain Standoff Distance in Semiconductor Devices
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Solution Overview
Problem
Conventional semiconductor device manufacturing faces electrical bridging defects due to excess bump material flowing outward during reflow, which lowers manufacturing yield and increases costs, while increasing pitch to prevent defects decreases interconnect density.
Innovation Solution
The introduction of dummy pillars maintains a standoff distance between the semiconductor die and substrate, preventing excess bump material from bridging adjacent conductive pillars by ensuring a fixed distance, thus reducing defects while allowing for fine interconnect pitches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pitch between conductive pillars is increased to prevent electrical bridging, then electrical bridging defects are reduced, but interconnect density decreases
Solution Approach 1:
The patent introduces a dummy pillar as an intermediary element positioned between adjacent conductive pillars. This dummy pillar acts as a physical barrier that prevents excess bump material from bridging adjacent conductive pillars during reflow, thereby maintaining fine pitch while preventing electrical bridging defects
Solution Approach 2:
The patent segments the interconnect structure by introducing dummy pillars that divide the space between conductive pillars. This segmentation creates isolated regions that contain excess bump material, preventing it from reaching adjacent conductive pillars and causing electrical bridges
Data Source
AI summary
A semiconductor device has a semiconductor die with an insulation layer formed over an active surface of the semiconductor die. A conductive layer is formed over the first insulating layer electrically connected to the active surface. A plurality of conductive pillars is formed over the conductive layer. A plurality of dummy pillars is formed over the first insulating layer electrically isolated from the conductive layer and conductive pillars. The semiconductor die is mounted to a substrate. A height of the dummy pillars is greater than a height of the conductive pillars to maintain the standoff distance between the semiconductor die and substrate. The dummy pillars can be formed over the substrate. The dummy pillars are disposed at corners of the semiconductor die and a central region of the semiconductor die. A mold underfill material is deposited between the semiconductor die and substrate.