Semiconductor Moisture Barrier via Metallic Adhesion Layer
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Solution Overview
Problem
Moisture penetration through the boundary between a semiconductor layer and its protective film can lead to corrosion of external lead electrodes, degrading the reliability of semiconductor devices, especially due to the low moisture resistance of polyimide protective films.
Innovation Solution
A semiconductor device design that includes a GaAs-based, InP-based, or GaN-based semiconductor layer with a first silicon nitride film and a protective film made of polyimide or benzocyclobutene, where a metallic layer, such as titanium, tantalum, or platinum, is continuously provided between the semiconductor layer and the protective film, enhancing adhesion and resistance to moisture penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a protective film made of polyimide is provided on the semiconductor layer, then the semiconductor layer is protected from stress and fouling, but moisture penetrates through the protective film and corrodes the external lead electrode
Solution Approach 1:
The patent applies composite materials by combining a silicon nitride film (first protective film) with a polyimide or benzocyclobutene protective film. The silicon nitride film provides high moisture resistance while the polyimide/benzocyclobutene film provides mechanical protection and stress relief. This composite structure resolves the contradiction by integrating materials with complementary properties - one excellent at moisture barrier (silicon nitride) and another excellent at mechanical protection (polyimide), achieving both strength and reliability simultaneously.
2Stability of the object's composition
If a metallic film is provided at the boundary between the protective film and scribe line to suppress exfoliation, then the protective film adhesion is improved, but moisture penetration path is created at the boundary between semiconductor layer and protective film
Solution Approach 1:
The patent applies local quality by providing the metallic film (titanium, tantalum, or platinum) specifically at the boundary region between the silicon nitride film and the scribe line, rather than uniformly across the entire structure. This localized metallic layer enhances adhesion precisely where the silicon nitride film meets the substrate, preventing exfoliation at this critical interface, while the rest of the silicon nitride film maintains its moisture barrier function. The selective placement resolves the contradiction by improving adhesion locally without creating widespread moisture penetration paths.
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
The solution effectively suppresses moisture penetration and corrosion of ohmic electrodes, thereby enhancing the reliability and longevity of semiconductor devices by using a metallic layer with high adhesion properties to prevent moisture from reaching the semiconductor layer.
Implementation Method 1
a first metallic layer that is composed of one of titanium, tantalum and platinum, and is continuously provided from a first portion located between the semiconductor layer and the protective film to a second portion located between the end portion of the first silicon nitride film and the protective film, the first metallic layer being in contact with the surface of the semiconductor layer and a surface of the end portion of the first silicon nitride film
Data Source
AI summary
A semiconductor device includes: a semiconductor layer composed of one of GaAs based semiconductor, InP-based semiconductor, and GaN-based semiconductor; a first silicon nitride film that is provided on the semiconductor layer, and of which an end portion is in contact with a surface of the semiconductor layer; a protective film that is composed of one of polyimide and benzocyclobutene, and is provided on the semiconductor layer and the first silicon nitride film, the protective film covering the end portion of the first silicon nitride film; and a first metallic layer that is composed of one of titanium, tantalum and platinum, and is continuously provided from a first portion located between the semiconductor layer and the protective film to a second portion located between the end portion of the first silicon nitride film and the protective film, the first metallic layer being in contact with the surface of the semiconductor layer and a surface of the end portion of the first silicon nitride film.