Three-Layered Barrier Metal Laminate for Semiconductor Moisture Resistance
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Solution Overview
Problem
Conventional semiconductor device manufacturing processes face issues with moisture resistance and crack formation due to exposed barrier metal laminates and Si nodule growth, leading to increased manufacturing costs and failure rates.
Innovation Solution
A semiconductor device with a three-layered barrier metal laminate structure, including a Ti film, a TiN film, and an Al-Si film, where the uppermost Ti film provides excellent moisture resistance and prevents Si nodule formation by reacting with Al-Si alloy film atoms to form titanium silicides, eliminating the need for a separate SiN passivation film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional two-layer barrier metal laminate (Ti film and TiN film) is used, then the manufacturing process is simple, but the exposed barrier metal laminate surface has poor moisture resistance
Solution Approach 1:
The barrier metal laminate is segmented into three distinct layers: a lower Ti film layer, a middle TiN film layer, and an upper Ti film layer. This segmentation allows each layer to perform its specific function - the TiN layer provides the base barrier properties while the upper Ti layer specifically addresses moisture resistance of exposed surfaces.
Solution Approach 2:
The uppermost Ti film layer is specifically designed to provide excellent moisture resistance at the exposed barrier metal laminate surface. This local quality enhancement ensures that the critical exposed areas have superior moisture protection without requiring a complete redesign of the entire barrier structure.
2Reliability
If Al-Si alloy film is used for the metal electrode wiring laminate, then the electrical conductivity is good, but Si nodules form during heat treatment causing cracks and failures
Solution Approach 1:
The uppermost Ti film layer is positioned to react with Si atoms from the Al-Si alloy film before they can form harmful nodules. This preliminary anti-action prevents Si nodule formation by chemically binding the Si atoms into titanium silicides, eliminating the root cause of subsequent crack formation during heat treatment.
Solution Approach 2:
The Si atoms that would normally form harmful nodules and cause cracks are converted into beneficial titanium silicides through reaction with the upper Ti film. This transformation converts a harmful factor (Si nodules) into a beneficial one (titanium silicide layer that prevents cracking).
3Reliability
If a separate SiN passivation film is added to prevent Si nodule growth, then crack-related failures are reduced, but the device complexity and manufacturing cost increase
Solution Approach 1:
The uppermost Ti film layer serves dual functions: it provides moisture resistance for the exposed barrier metal surface and simultaneously prevents Si nodule growth by reacting with Si atoms. This merging of functions eliminates the need for a separate SiN passivation film, reducing device complexity while maintaining reliability.
Solution Approach 2:
The upper Ti film layer is designed to perform multiple functions: moisture barrier protection and Si nodule prevention. This multi-functionality allows a single layer to replace what would traditionally require multiple separate layers, simplifying the overall device structure.
4Manufacturing precision
If the barrier metal laminate is exposed after Al-Si alloy film etching, then the wiring pattern is formed, but the exposed surface is susceptible to moisture and contamination
Solution Approach 1:
The upper Ti film layer is formed before the Al-Si alloy film etching process. This preliminary action ensures that the barrier metal laminate surface is already protected with a moisture-resistant layer before exposure occurs during subsequent etching and wiring pattern formation processes.
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 solution enhances moisture resistance and reduces crack-related failures in the semiconductor device, achieving improved reliability with a single-layered passivation film and preventing Si nodule growth, thus lowering manufacturing costs and failure rates.
Implementation Method 1
the uppermost Ti film prevents Si nodule formation by reacting with Al-Si alloy film atoms to form titanium silicides
Implementation Method 2
Ti film 3 and TiN film 4 are formed by sputtering
Data Source
AI summary
A semiconductor device includes a semiconductor substrate; a metal electrode wiring laminate on the semiconductor substrate, the metal electrode wiring laminate being patterned with a predetermined wiring pattern; the metal electrode wiring laminate including an undercoating barrier metal laminate and aluminum or aluminum alloy film on the undercoating barrier metal laminate; and organic passivation film covering the metal electrode wiring laminate, wherein the barrier metal laminate is a three-layered laminate including titanium films sandwiching a titanium nitride film. The semiconductor device according to the invention facilitates improving the moisture resistance of the portion of the barrier metal laminate exposed temporarily in the manufacturing process, facilitates employing only one passivation film, facilitates preventing the failures caused by cracks from occurring and the failures caused by Si nodules remaining in the aluminum alloy from increasing.