Chip Layout Latch-Up Structure Identification for IC Reliability
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Solution Overview
Problem
There is a lack of reliable and comprehensive methods for identifying and inspecting parasitic latch-up paths in integrated circuits, which poses a significant challenge to ensuring the reliability of semiconductor products by preventing latch-up failures.
Innovation Solution
A method is provided that identifies latch-up structures in chip layouts by finding specific heavily doped regions and their connections to input/output pads, forming parasitic transistors and resistors that can trigger latch-up effects, allowing for the detection of potential latch-up paths using predefined design rules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If comprehensive latch-up path detection is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The latch-up detection method is segmented into distinct identification rules: Rule 1 identifies PMOS-induced latch-up paths by detecting specific doped region configurations, while Rule 2 identifies NMOS-induced latch-up paths separately. This segmentation allows comprehensive coverage of different latch-up mechanisms without requiring a single complex detection algorithm, thereby improving reliability while managing inspection complexity.
2Measurement precision
If detailed latch-up structure identification is performed, then measurement precision is improved, but difficulty of detecting and measuring increases
Solution Approach 1:
The detection method applies local quality by focusing inspection efforts on specific critical regions where latch-up paths are most likely to form. Rule 1 specifically examines regions around PMOS transistors with particular doped region configurations, while Rule 2 examines regions around NMOS transistors. This localized approach improves detection accuracy for parasitic paths without requiring exhaustive analysis of the entire circuit, thereby reducing inspection difficulty while maintaining high precision.
Data Source
AI summary
A method for identifying a latch-up structure includes the following: in a chip layout, a first N-type heavily doped region connected to a first input/output pad and located in a P-type substrate is found; a first P-type heavily doped region located in an N-well and a second P-type heavily doped region located in the P-type substrate, both of which are adjacent to the first N-type heavily doped region, are found; a second N-type heavily doped region adjacent to the first P-type heavily doped region and located in the N-well is found, wherein the N-well is located on the P-type substrate; and an area formed by the first P-type heavily doped region, the first N-type heavily doped region, the second P-type heavily doped region, the second N-type heavily doped region, the N-well and the P-type substrate is identified as the latch-up structure.