Wafer Pad Layout Separating Probe Marks From Bonding Surfaces
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Solution Overview
Problem
Probe marks on bond pads during electrical testing lead to decreased bonding quality and increased resistance due to bubble formation between bonded wafers, affecting electrical reliability.
Innovation Solution
A wafer structure design with additional bond pads or filling structures that ensure flatness, preventing overlap with probe marks, thereby enabling favorable bonding quality and reducing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrical tests are performed on bond pads with probes, then electrical quality of each die can be detected, but probe marks are generated on the bond pads
Solution Approach 1:
The invention divides the pad structure into two separate components: test pads for electrical testing and bond pads for bonding. The test pads are specifically designed to receive probe marks, while the bond pads remain untouched. This segmentation allows electrical testing to be performed on test pads without generating harmful probe marks on the bond pads, thus resolving the contradiction between measurement capability and harm prevention.
Solution Approach 2:
The invention introduces test pads as an intermediary element between the probing system and the bond pads. The test pads serve as a mediator that absorbs the harmful effect of probe marks, allowing electrical testing to be conducted without directly impacting the bond pads. This intermediary structure enables the detection of electrical quality while protecting the bond pads from probe mark contamination.
2Productivity
If bonding is performed on bond pads with probe marks, then wafer bonding can be completed, but bubbles are generated between bond pads resulting in decreased bonding quality
Solution Approach 1:
The invention extracts the testing function from the bond pads and relocates it to dedicated test pads. By taking out the testing operation from the bonding area, the bond pads are preserved free of probe marks. This extraction ensures that when bonding is performed, no probe marks exist on the bond pads, preventing bubble formation and maintaining high bonding quality while still enabling electrical testing to be completed.
Solution Approach 2:
The invention segments the pad functionality into separate test pads and bond pads. Test pads are dedicated to electrical testing and can accommodate probe marks, while bond pads are dedicated to bonding operations and remain free of contaminants. This functional segmentation allows bonding to be completed on clean bond pads without the presence of probe marks, thereby preventing bubbles and ensuring high bonding quality.
3Measurement precision
If probe marks are present on bond pads, then electrical testing can be performed, but resistance increases after bonding
Solution Approach 1:
The invention segments the electrical testing function from the bonding function by creating separate test pads and bond pads. Test pads are designed to receive probe marks during electrical testing, while bond pads remain free of such marks. This segmentation ensures that electrical testing can be performed on test pads without increasing resistance on the bond pads, thereby maintaining low resistance after bonding while preserving electrical testing capability.
Solution Approach 2:
The invention introduces test pads as an intermediary structure that bears the electrical testing operation and associated probe marks. This intermediary allows electrical testing to be conducted without directly affecting the bond pads, thus preventing resistance increase on the bond pads while maintaining the ability to perform electrical testing on the test pads.
Data Source
AI summary
A wafer structure and a manufacturing method thereof are provided. The wafer structure includes a substrate structure, a first dielectric layer, multiple test pads, a second dielectric layer, and multiple bond pads. The first dielectric layer is disposed on the substrate structure. The test pads are disposed in and exposed outside the first dielectric layer. Each test pad has a probe mark. The second dielectric layer is disposed on the first dielectric layer. The second dielectric layer has a top surface away from the test pads. Multiple bond pads are disposed in and exposed outside the second dielectric layer. Each bond pad is electrically connected to the corresponding test pad. The bond pads have bonding surfaces away from the test pads. The bonding surfaces are flush with the top surface. In the normal direction of the substrate structure, each bond pad does not overlap the probe mark of the corresponding test pad.