Semiconductor Electrode Pad Moisture Barrier Design
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Solution Overview
Problem
Existing semiconductor devices face reliability issues due to moisture penetration between the protective silicon nitride film and the electrode pad, leading to corrosion and potential short circuits, especially when the insulative cover film does not provide adequate coverage.
Innovation Solution
A semiconductor device structure is implemented with a metal layer, such as Ti, Ta, or Pt, that contacts the end portion of a silicon nitride film on the electrode pad, exposing another part of the pad surface, thereby enhancing adhesion and resistance to moisture penetration, while minimizing stress-induced cracks by limiting the metal layer's presence to specific areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silicon nitride film is provided on the electrode pad to protect from stress and fouling, then protection capability is improved, but moisture penetration occurs at the boundary between the film and electrode pad leading to corrosion
Solution Approach 1:
A metal layer (Ti, Ta, or Pt) is introduced as an intermediary between the silicon nitride film and the electrode pad. This metal layer forms a barrier that prevents moisture from penetrating along the boundary interface, while maintaining adhesion between the insulative film and electrode pad through its oxidation resistance properties.
2Strength
If a ball of bonding wire is provided on the insulative cover film to improve adhesion, then adhesion is improved, but cracks occur in the insulative cover film when pressure is applied
Solution Approach 1:
The metal layer is selectively positioned at the boundary region between the silicon nitride film and electrode pad, providing localized reinforcement and moisture barrier functionality where it is most needed, while allowing the bulk of the insulative film to maintain its structural integrity without unnecessary stress concentration points.
3Reliability
If the metal layer contacts both the electrode pad and silicon nitride film end portion, then moisture penetration is suppressed, but device complexity increases
Solution Approach 1:
The protective structure is segmented into distinct functional zones: the silicon nitride film provides general protection, the metal layer specifically addresses moisture penetration at the boundary, and portions of the electrode pad remain exposed for electrical contact. This segmentation allows each component to perform its specific function efficiently without unnecessary complexity.
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
This configuration effectively suppresses moisture penetration and corrosion, improving the long-term reliability of the semiconductor device by preventing moisture from reaching the electrode pad and ohmic electrode, thus reducing the risk of short circuits and extending the device's lifespan.
Implementation Method 1
a metal layer that contacts a part of a surface of the electrode pad and the end portion of the silicon nitride film... enhancing adhesion and resistance to moisture penetration
Implementation Method 2
the metal layer including any of Ti, Ta and Pt... suppressing moisture penetration and corrosion
Data Source
AI summary
A semiconductor device includes a semiconductor layer, an electrode pad that is composed of Au and is provided on the semiconductor layer, a silicon nitride film provided on the semiconductor layer and the electrode pad so that an end portion of the silicon nitride film is located, and a metal layer that contacts a part of a surface of the electrode pad and the end portion of the silicon nitride film and is provided so that another part of the surface of the electrode pad is exposed, the metal layer including any of Ti, Ta and Pt.