Semiconductor Test Key via String for Low-k Dielectric Scribing
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Solution Overview
Problem
Conventional mechanical and laser cutting methods are not well suited for scribing advanced semiconductor wafers with low-k dielectric materials, leading to damage such as chips and cracks due to their low density and sensitivity to thermal stress.
Innovation Solution
A semiconductor device with a test line structure featuring a semiconductive substrate, a dielectric stack, probe pads, and single via string stacking that electrically connects the probe pads to a test key, minimizing the risk of cracking during scribing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional mechanical or laser saw cutting methods are used to separate wafers between individual chips, then the wafer can be singulated, but the low-k dielectric materials are damaged causing chips and cracks due to their low density and sensitivity to thermal stress
Solution Approach 1:
The test line area is segmented into multiple regions with different dielectric material properties. The first test line area contains low-k dielectric material for sensitivity testing, while the second test line area contains high-k dielectric material for mechanical strength testing. This segmentation allows independent optimization of each region's properties to serve different testing purposes without compromising overall wafer integrity.
Solution Approach 2:
Different regions of the test line area are assigned different dielectric material qualities - the first region uses low-k material with specific electrical properties for accurate electrical testing, while the second region uses high-k material with superior mechanical properties to withstand cutting forces. This local differentiation resolves the contradiction by providing both electrical sensitivity and mechanical robustness in appropriate locations.
2Measurement precision
If low-k dielectric materials are used in test line areas, then electrical testing sensitivity is improved, but the materials become susceptible to damage during scribing due to their low density and thermal stress sensitivity
Solution Approach 1:
The test line structure is divided into two separate areas: the first test line area uses low-k dielectric material optimized for electrical testing sensitivity, while the second test line area uses high-k dielectric material optimized for mechanical strength. This segmentation allows each region to be optimized for its specific function without compromise.
Solution Approach 2:
Different dielectric material qualities are applied locally to different test line regions based on their functional requirements. The low-k region provides superior electrical characteristics for sensitive measurements, while the high-k region provides enhanced mechanical properties for damage resistance during scribing operations.
Data Source
AI summary
A semiconductor device includes a semiconductive substrate, a dielectric stack disposed over the semiconductive substrate, a probe pad formed on the dielectric stack, a test key embedded in the semiconductor device and a single via string stacking extending along a direction from a level of the probe pad to the semiconductive substrate and electrically connecting the periphery of the probe pad to the test key. A semiconductor device includes a semiconductive substrate, a dielectric stack, a probe pad, a test key, an extension segment electrically connected to the periphery of the probe pad and laterally extending from the probe pad from a top view, and a single via string stacking extending along a direction from the probe pad to the semiconductive substrate and electrically connecting the extension segment to the test key. The single via string stacking and the probe pad are laterally offset from a top view.