Semiconductor Substrate Contact Resistance Stabilization
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Solution Overview
Problem
Stabilizing the coupling resistance of substrate contacts formed in deep trenches within semiconductor devices is challenging due to the difficulty in achieving proper coupling resistance and fabrication methods.
Innovation Solution
A method of manufacturing semiconductor devices involves forming a semiconductor substrate with specific layer configurations, including a p-type silicon layer, an n-type silicon layer, and a second p-type silicon layer, and creating a trench that reaches the first p-type silicon layer, followed by the formation of a silicide layer and a plug electrode using a laminated film of CVD-Ti, CVD-TiN, and CVD-W films, which reduces resistance and stabilizes the substrate contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a deep trench is formed to reach the substrate for substrate contact, then electrical connection to the substrate is achieved, but the coupling resistance becomes difficult to stabilize
Solution Approach 1:
The patent applies composite materials by forming a silicide layer (e.g., cobalt silicide) on the substrate contact region. This silicide layer has lower resistance than pure metal and provides stable electrical characteristics. The combination of metal plug electrode and silicide layer creates a composite contact structure that stabilizes coupling resistance while maintaining manufacturability.
Solution Approach 2:
The patent changes the physical and chemical parameters of the substrate contact by forming a silicide layer through thermal diffusion or chemical vapor deposition. This transforms the contact interface from a simple metal-substrate interface to a metal-silicide-substrate structure with optimized resistance parameters and improved stability.
2Reliability
If a deep trench is formed to reach the substrate, then substrate contact is established, but the aspect ratio of the trench increases making fabrication difficult
Solution Approach 1:
The patent applies preliminary action by forming the silicide layer on the substrate surface before depositing the plug electrode material into the trench. This pre-formed silicide layer serves as a base that facilitates subsequent electrode formation and reduces the effective depth that needs to be filled, easing the fabrication of high aspect ratio trenches.
3Manufacturing precision
If a simple metal plug is formed in the deep trench, then the trench can be filled, but the embedding properties and resistance are not optimized
Solution Approach 1:
The patent uses composite materials by combining a silicide layer with the plug electrode material. The silicide layer provides low resistance and good adhesion to the substrate, while the plug electrode material (such as tungsten or copper) provides structural stability and low overall resistance. This composite structure optimizes both embedding properties and electrical characteristics.
Solution Approach 2:
The patent applies local quality by forming the silicide layer specifically at the substrate contact region where it is most needed for resistance reduction and adhesion enhancement. The rest of the plug electrode can use different materials optimized for their specific functions, creating a structure with locally optimized properties throughout.
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 approach improves the characteristics of semiconductor devices by stabilizing the substrate contact resistance and enhancing the embedding properties of the plug electrode, reducing the aspect ratio of the deep trench and minimizing resistance issues.
Implementation Method 1
forming a silicide layer on the first p-type silicon layer exposed at the bottom of the first trench, the silicide layer including a first metal film
Implementation Method 2
forming a plug electrode in the trench using a laminated film of CVD-Ti, CVD-TiN, and CVD-W films
Data Source
AI summary
To improve the characteristics of a semiconductor device having a substrate contact formed in a deep trench. In a method of forming a plug PSUB in a deep trench DT2 that penetrates an n-type buried layer NBL and reaches a p-type epitaxial layer PEP1, the plug PSUB is formed in the deep trench DT2 after a metal silicide layer SIL1 is formed in the p-type epitaxial layer PEP1. The metal silicide layer SIL1 is formed using a PVD-first metal film (a first metal film formed by PVD). A first barrier metal film BM1 at the bottom of the plug PSUB is a CVD-second metal film (a second metal film formed by CVD). The first metal film is a metal film different from the second metal film.