Semiconductor Pad Segmentation for Probe Contact Reliability
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Solution Overview
Problem
As large-scale integrated circuit (LSI) devices become more complex, the testing process becomes increasingly complicated, leading to pad damage from repeated contact with probe cards, resulting in poor quality devices and increased size due to larger pads to mitigate damage.
Innovation Solution
The semiconductor device incorporates multiple divided pad portions for test-subject circuits and single pad portions for test-irrelevant circuits, allowing for reduced contact points and preventing pad damage, while maintaining a compact size by not dividing all pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pads are made larger in area to reduce repeated contacts of pins with the same points, then pad damage is reduced, but the LSI device becomes larger
Solution Approach 1:
Each pad is divided into multiple pad portions (first pad portions for test-subject circuits and second pad portions for test-irrelevant circuits). This segmentation allows the probe card pins to contact different portions across multiple test operations, distributing the mechanical stress and preventing concentrated damage at single points, thereby reducing overall pad damage without increasing the total pad area.
Solution Approach 2:
Different pad portions are assigned different functions: first pad portions connect to test-subject circuits requiring multiple test contacts, while second pad portions connect to test-irrelevant circuits requiring fewer contacts. This local differentiation optimizes the contact distribution strategy, allowing repeated contacts on first pad portions while minimizing contacts on second pad portions, thus protecting the overall pad structure without expanding area.
2Reliability
If pads are made larger in area to accept repeated contacts, then bonding points can be changed from contacting points, but the LSI device size increases undesirably
Solution Approach 1:
Pads are segmented into multiple portions with distinct contact histories. First pad portions have been contacted multiple times during testing and can serve as bonding points for wire bonding to different locations. Second pad portions have fewer contacts and can also serve as bonding points. This segmentation ensures that wire bonding can be performed at optimal locations independent of test contact points, guaranteeing bonding quality without requiring larger pad areas.
Solution Approach 2:
Different regions of the pad structure are optimized for different purposes: first pad portions are designed to withstand repeated test contacts and then serve as bonding points, while second pad portions are designed with fewer contacts and also serve as bonding points. This local optimization ensures that bonding quality is maintained across all pad regions without necessitating an overall increase in pad area.
Data Source
AI summary
A semiconductor device is provided with test-subject circuit 1, test-irrelevant circuit 2, first pads used for the test-subject circuit, and second pads used for the test-irrelevant circuit. The first pads include a plurality of divided pad portions while each of the second pads is provided with a single pad portion.