Semiconductor Pad Bonding Test Circuit Using Phase Difference Detection
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Solution Overview
Problem
Existing semiconductor devices face challenges in accurately detecting incomplete bump bonding between pads, which can lead to signal delays and malfunctions, as current methods cannot reliably distinguish between defects in bump bonding and internal circuit issues.
Innovation Solution
A test circuit is introduced that includes a phase difference detection unit to compare signals received through multiple pads, determining if bump bonding is complete by assessing the phase difference between these signals and outputting a result signal based on a preset delay threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If bump bonding is used to reduce pad size, then pad size is reduced, but detection precision of bonding defects deteriorates
Solution Approach 1:
The patent introduces a test circuit as an intermediary system that includes signal generation units, reception units, and a determination unit. This test circuit mediates between the small pads and the defect detection process, enabling accurate detection of bump bonding defects despite the reduced pad size by using external signal injection and phase difference measurement
2Reliability
If bump bonding is incomplete, then signal transmission may still occur, but reliability of signal transmission deteriorates
Solution Approach 1:
The patent implements preliminary testing of bump bonding quality before actual signal transmission. The test circuit performs phase difference measurements on test signals injected into the pads, allowing incomplete or defective bump bonding to be detected and flagged before it causes signal delays or malfunctions in normal operation
Solution Approach 2:
The determination unit provides feedback about the quality of bump bonding by comparing phase differences against reference values. This feedback mechanism allows the system to identify incomplete bonding and prevent or flag potential signal transmission issues
3Measurement precision
If conventional testing methods are used, then manufacturing process is simple, but detection precision of partial bonding defects deteriorates
Solution Approach 1:
The test circuit is designed with multi-functionality, serving both normal signal transmission and defect detection purposes. The same pads and reception units used for signal input are also utilized for receiving test signals and performing phase difference measurements, reducing the need for entirely separate testing infrastructure
Data Source
AI summary
A test circuit includes a phase difference detection unit and a determination unit. The phase difference detection unit detects a phase difference between a first signal received through a first pad and a second signal received through a second pad. The determination unit compares the detected phase difference with a preset amount of delay and outputs a result signal.