3D Crack-Stop Structure for Thin Glass Substrates
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Solution Overview
Problem
Thin glass substrates used in integrated microelectronic devices are brittle and prone to chipping or damage during handling, leading to substrate breakage and yield loss, as existing crack-stop features only address in-plane cracks and not through-substrate cracks.
Innovation Solution
A three-dimensional crack-stop structure is formed in, through, and around the edges of the substrate, comprising continuous trenches and vias, filled with a protective layer, to prevent through-substrate cracks from propagating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If thin glass substrates are used in integrated microelectronic devices, then device miniaturization and integration are improved, but substrate brittleness increases leading to chipping and breakage during handling
Solution Approach 1:
The substrate edge is segmented into multiple regions by forming trenches and via holes that divide the continuous edge structure into discrete segments. This segmentation prevents crack propagation across the entire edge while maintaining the overall structural integrity of the thin substrate.
Solution Approach 2:
Protective structures (trenches filled with protective material) are formed beforehand at the substrate edge before handling and processing. These pre-formed protective features absorb and dissipate mechanical stresses and crack energies that would otherwise propagate through the thin substrate during handling.
2Reliability
If multiple trenches and vias are formed around substrate edges, then crack propagation is prevented, but manufacturing complexity increases
Solution Approach 1:
Multiple protective features (trenches and via holes) are merged into an integrated crack-stop structure that works synergistically. The trenches and vias are combined to form a unified protective system that addresses both lateral and vertical crack propagation paths, reducing the need for separate protective structures.
Solution Approach 2:
The crack-stop structure performs multiple functions simultaneously: it provides lateral crack stopping through trenches, vertical crack stopping through via holes, edge strengthening, and stress distribution. This multi-functionality reduces the need for additional separate protective features, simplifying the overall manufacturing process.
Data Source
AI summary
A method of forming a 3D crack-stop structure in, through, and wrapped around the edges of a substrate to prevent through-substrate cracks from propagating and breaking the substrate and the resulting device are provided. Embodiments include providing a substrate including one or more dies; forming a continuous first trench near an outer edge of the substrate; forming a continuous second trench parallel to and on an opposite side of the first trench from the outer edge; forming a continuous row of vias parallel to and on an opposite side of the second trench from the first trench, forming a continuous third trench parallel to and near an outer edge of each of the dies; forming a protective layer wrapping around the outer edge of the substrate and over and filling the trenches and vias; and patterning active areas of the substrate between the vias and the third trench.