Angled Die Seal Slots for IC Noise Reduction
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Solution Overview
Problem
Die seals in integrated circuits allow induced currents to circulate, causing noise in circuits, especially when grounded, and existing solutions that break the die seal to prevent crack propagation increase chip size and cost.
Innovation Solution
Breaking the die seal with angled or vertically staggered slots on conductor layers to prevent circular current flow, ensuring electrical isolation and minimizing via pitch impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the die seal is kept continuous to protect the substrate from structural stresses and moisture, then the protection function is improved, but induced currents can circulate around the die seal causing noise in circuits
Solution Approach 1:
The continuous die seal is segmented by introducing slots that break the circular conductor path. The slots create discontinuities in the die seal structure, preventing circulating currents while maintaining the protective enclosure. Each slot acts as a break in the conductor path, eliminating the Faraday ring effect that causes noise.
2Object-generated harmful factors
If the die seal is broken with a straight slot to prevent crack propagation, then the noise is reduced, but parallel conductor strips must be added to prevent cracks from propagating through the slot
Solution Approach 1:
The slot is designed with an asymmetric angled configuration rather than a straight vertical slot. This asymmetric geometry prevents crack propagation along the slot edges while maintaining electrical isolation. The angled sides create a configuration where cracks cannot easily bridge across the slot, eliminating the need for additional parallel conductor strips.
3Strength
If parallel conductor strips are added outside the die seal to prevent crack propagation, then crack resistance is improved, but the chip size increases
Solution Approach 1:
The die seal is segmented with angled slots that create multiple discontinuities in the conductor path. These slots are positioned and angled to intercept potential crack paths without requiring additional external conductor strips. The segmentation approach provides both electrical isolation and mechanical crack prevention within the existing die seal boundaries.
4Strength
If the die seal is broken to prevent crack propagation, then crack resistance is improved, but the manufacturing cost increases
Solution Approach 1:
The slot structure serves dual functions: it provides electrical isolation to prevent noise while simultaneously acting as a crack propagation barrier. By merging these two functions into a single structural feature, the design eliminates the need for separate crack prevention measures, thereby reducing manufacturing complexity and cost.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents edge crack propagation and reduces induced noise while maintaining chip size and cost efficiency by breaking the Faraday ring and ensuring electrical isolation without increasing the chip's area for additional conductor strips.
Implementation Method 1
Die seals in integrated circuits allow induced currents to circulate, causing noise in circuits
Implementation Method 2
One function of die seals 101 is to terminate any physical cracks penetrating from the die edge into the die interior
Data Source
AI summary
A die seal is broken in at least one place for a conductor strip formed on each conductor layer. Accordingly, no current can flow in a circular pattern around the entire perimeter of the chip. In some embodiments, an angled slot is provided in the original die seal. The angled slots may be vertically aligned. Alternatively, the slots may be vertically staggered or straight. When vertically staggered, the slots on each conductor layer are vertically offset.