Thru-Silicon Via Testing via Wafer Tape Conductive Path
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Solution Overview
Problem
Testing thru-silicon vias (TSVs) in 3D and 2.5D integrated circuits is challenging due to the fragility of silicon dies, making it difficult to probe both sides for defects like shorts and opens, which can lead to undetected defective TSVs and dies.
Innovation Solution
Attaching a silicon die with TSVs to a wafer tape of known resistivity and measuring the resistance of an electrical path through the tape to probe for defects, allowing testing from one side while using the tape as a conductive path between TSVs to detect shorts and opens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If both sides of the silicon die are probed to test TSVs, then measurement precision is improved, but the difficulty of operation increases due to silicon die fragility
Solution Approach 1:
A wafer tape with known resistivity is introduced as an intermediary between the silicon die and the testing equipment. The wafer tape serves as a conductive path that allows electrical signals to traverse through the TSVs without requiring direct probing of both die surfaces. This mediator enables indirect measurement while protecting the fragile silicon die from mechanical stress
Solution Approach 2:
The testing approach transitions from direct surface probing to edge-based measurement. By attaching the wafer tape to the die edge and measuring resistance through the TSVs via the tape, the method moves the measurement interface from the fragile top/bottom surfaces to the more robust edge region, effectively changing the dimensional approach to testing
2Ease of operation
If probing both sides of the die is omitted to avoid damage, then ease of operation is improved, but measurement precision deteriorates as defective TSVs go unnoticed
Solution Approach 1:
The wafer tape acts as an intermediary that enables complete TSV testing through a simplified single-side attachment process. The tape's known resistivity provides a reference that allows accurate defect detection without requiring complex dual-side probing setups, thus maintaining measurement precision while improving operational simplicity
Solution Approach 2:
The wafer tape's inherent electrical properties (known resistivity) are utilized to perform the measurement function. The tape itself serves as both the mounting substrate and the measurement reference, eliminating the need for additional complex testing equipment or procedures to achieve accurate TSV defect detection
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
Enables effective detection of TSV defects without physically probing both sides of the die, reducing the risk of missing defective TSVs and improving the reliability of TSV testing by using resistance measurements to identify open or short circuits.
Implementation Method 1
measuring the resistance of an electrical path from the exposed side of the die through a TSV across the wafer tape and back through another TSV
Data Source
AI summary
A system and a method for testing thru silicon vias (TSVs) in a silicon die. A silicon die containing multiple TSVs is mounted on a wafer tape. Two probe points are probed on the exposed side of the silicon die. A resistance is measured between the two probe points and an electrical integrity is determined based on the measured resistance.