Test Line Placement to Reduce Low-k Dielectric Peeling
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Solution Overview
Problem
The challenge in semiconductor wafer manufacturing is the peeling and delamination of low-k dielectric materials at die corners due to stress from the sawing process, which affects device reliability and leads to waste of wafer area and reduced chip density, as existing design rules restrict test line placement and length.
Innovation Solution
A semiconductor wafer structure with test lines crossing the intersection region of scribe lines, where test pads are formed only outside a defined free region, preventing test pads from being sawed twice and reducing the likelihood of low-k dielectric peeling, while allowing flexible test line placement and minimizing wafer area waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If test pads are placed on scribe lines following conventional design rules, then testing can be performed, but low-k dielectric peeling and delamination occur at die corners due to sawing stress
Solution Approach 1:
The invention extracts test pads from the harmful scribe line areas and places them in dedicated test line regions that are specifically designed to avoid stress concentration zones. This separation removes the conflict between testing requirements and stress-induced peeling problems.
Solution Approach 2:
The invention creates different structural qualities in different regions: test lines are designed with specific width and positioning characteristics in low-stress areas, while die corners maintain enhanced structural integrity. Each region has optimized properties suited to its functional requirements.
2Reliability
If test lines are restricted from crossing scribe line intersections, then peeling is reduced, but test line length is limited and wafer area is wasted
Solution Approach 1:
The invention segments the wafer into distinct functional regions: test line regions where testing occurs and die regions where chips are manufactured. This segmentation allows test lines to extend across the wafer surface in optimized paths without compromising chip density or causing peeling.
Solution Approach 2:
The invention utilizes the two-dimensional wafer surface more efficiently by routing test lines along optimized paths that cross scribe line intersections at appropriate angles and positions, transforming the constraint into a design opportunity for better space utilization.
3Adaptability or versatility
If test pads are placed in intersection areas of scribe lines, then test line placement flexibility is improved, but test pads are sawed twice causing increased peeling
Solution Approach 1:
The invention extracts test pads from the harmful intersection areas of scribe lines and places them in dedicated test line regions. This separation eliminates the double-sawing problem while preserving test line placement flexibility through proper routing design.
Data Source
AI summary
A semiconductor wafer structure includes a plurality of dies, a first scribe line extending along a first direction, a second scribe line extending along a second direction and intersecting the first scribe line, wherein the first and the second scribe lines have an intersection region. A test line is formed in the scribe line, wherein the test line crosses the intersection region. Test pads are formed in the test line and only outside a free region defined substantially in the intersection region.