Pad Electrode Crack Prevention via Through Via Support
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Solution Overview
Problem
Semiconductor devices with thin pad electrodes are prone to cracking under stress, such as physical impact, due to the thin thickness of the electrodes, which can render them unusable.
Innovation Solution
The semiconductor device design includes through vias and passivation film openings where the through via diameter is larger than the passivation film opening, with the through via edge positioned radially outside the passivation film edge, preventing cracks by supporting the pad electrode edge with the passivation film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the pad electrode thickness is reduced, then the device size can be minimized, but the electrode becomes prone to cracking under stress
Solution Approach 1:
The patent applies beforehand cushioning by positioning the through via to overlap with the pad electrode edge, creating a support structure that prevents crack propagation before stress can cause failure. The via acts as a pre-positioned reinforcement that cushions the thin electrode against mechanical stress during packaging and operation.
2Strength
If the through via diameter is increased to support the pad electrode edge, then crack prevention is improved, but the via may interfere with pad electrode exposure for inspection
Solution Approach 1:
The patent applies local quality by creating different structural characteristics in different regions: the through via provides structural support at the pad electrode edge where strength is needed, while the central pad electrode area remains exposed for inspection where accessibility is needed. This localized differentiation resolves the contradiction between support and exposure.
Solution Approach 2:
The patent resolves the spatial conflict by utilizing the vertical dimension - the through via extends through the substrate thickness, providing support from below the pad electrode without interfering with the top-surface exposure needed for inspection. This dimensional approach allows both functions to coexist.
3Strength
If the through via is positioned to support the pad electrode edge, then crack prevention is improved, but the via may cause stress concentration at the via edge
Solution Approach 1:
The via structure serves as beforehand cushioning that distributes mechanical stress away from the vulnerable thin pad electrode regions. By providing a robust support structure at the via location, the design prevents stress concentration from propagating through the thin electrode, thereby mitigating the harmful stress concentration effect.
Data Source
AI summary
A semiconductor device capable of preventing a crack from occurring in an electrode layer exposed through a through hole which is formed in a semiconductor substrate and a method of manufacturing the semiconductor device. In exemplary embodiments, a through via and an opening in a passivation film are disposed so that an opening diameter of the through via is larger than an opening diameter of the opening of the passivation film, and an opening edge of the through via is located outside an opening edge of the opening of the passivation film. In other embodiments, the through via and the opening of the passivation film are disposed so that the opening edge of the through via is disposed at a location which does not overlap with the opening edge (opening edge of a portion in contact with a pad electrode) of the opening of the passivation film.