Sacrificial Bond Pads for Semiconductor Wafer Testing
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Solution Overview
Problem
The semiconductor wafer probe testing process causes physical damage to normal bond pads, leading to electrical and mechanical failures, as the probe needle comes into contact with these pads, resulting in issues like short circuits, broken circuits, corrosion, and contamination.
Innovation Solution
The implementation of temporary counterpart sacrificial bond pads placed in functional scribe lanes on semiconductor wafers, which are electrically connected to normal bond pads, allowing testing without damaging the normal pads, and are subsequently destroyed during the singulation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the semiconductor wafer probe testing process uses normal bond pads for testing, then testing can be performed, but physical damage occurs to the bond pads causing electrical and mechanical failures
Solution Approach 1:
The bond pad functionality is segmented into two separate components: normal bond pads for their primary function (connecting to bond wires) and sacrificial bond pads for testing purposes. This segmentation allows each component to perform its specific function without interfering with the other, thereby maintaining bond pad integrity while enabling testing.
Solution Approach 2:
Sacrificial bond pads serve as an intermediary element between the testing probe and the normal bond pads. The probe contacts the sacrificial pad during testing, which mediates the mechanical stress and prevents direct contact with the normal bond pads, thus protecting them from damage.
2Reliability
If sacrificial bond pads are added to the semiconductor wafer, then normal bond pads are protected from damage, but the wafer configuration becomes more complex
Solution Approach 1:
The sacrificial bond pads are merged with the existing scribe lane structures on the wafer. By integrating the sacrificial pads into the already-present scribe lanes, the design adds minimal complexity while achieving the protective function. The sacrificial pads share the same physical space that would otherwise be unused.
Solution Approach 2:
The sacrificial bond pads are created as simplified copies of the normal bond pads, having the same basic structure and electrical connection properties but serving a different function. This copying approach allows the sacrificial pads to be implemented using standard fabrication processes without significantly increasing design complexity.
3Quantity of substance
If scribe lanes are minimized to maximize device count, then wafer capacity increases, but no space is available for sacrificial bond pads
Solution Approach 1:
The scribe lanes are given multiple functions: they continue to serve as spacing structures between devices and now also host the sacrificial bond pads for testing. This multi-functionality allows the scribe lanes to support testing infrastructure without increasing their size, thereby maintaining maximum device density on the wafer.
Data Source
AI summary
A method is provided for testing a semiconductor wafer, including individual semiconductor devices located on the semiconductor wafer, using temporary counterpart sacrificial bond pads. The method includes arranging individual semiconductor devices on the semiconductor wafer in a configuration having horizontal rows of the individual semiconductor devices separated by functional horizontal scribe lanes, and having vertical columns of individual semiconductor devices separated by functional vertical scribe lanes. The method includes creating the temporary counterpart sacrificial bond pads, located in the functional horizontal scribe lanes and/or vertical scribe lanes, that are electrically connected to corresponding normal individual bond pads located on individual semiconductor devices. The method also includes electrically testing the individual semiconductor devices using the temporary counterpart sacrificial bond pads, and destroying the temporary counterpart sacrificial bond pads upon completion of the electrical testing when the individual semiconductor devices are cut from the semiconductor wafer.