Nitrided Barrier for TSV Adhesion and Stress Reduction
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Solution Overview
Problem
Conventional barrier materials used in through-silicon vias (TSVs) are prone to delamination due to differences in thermal expansion and contraction with silicon substrates, leading to poor adhesion and potential electromigration issues.
Innovation Solution
A nitrided barrier is formed by reacting a barrier material with reactive nitrogen gas, creating a uniform nitride layer that adheres better to the silicon substrate and reduces stress, without the need for physical vapor deposition, which minimizes thickness variations and enhances adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional barrier materials are used in TSVs, then the TSV structure can be formed, but the barrier material delaminates from the silicon substrate due to thermal expansion mismatch
Solution Approach 1:
The patent applies composite materials by creating a nitrided barrier layer that combines the original barrier material with nitrogen-containing compounds. This composite structure provides both the thermal expansion compatibility needed to match silicon substrate and the adhesion properties required to prevent delamination during thermal cycling
Solution Approach 2:
The patent changes the chemical composition parameters of the barrier material by introducing nitrogen through nitridation processes. This parameter change modifies the thermal expansion coefficient to better match silicon while simultaneously improving adhesion, resolving the contradiction between thermal compatibility and bonding strength
2Manufacturing precision
If physical vapor deposition is used to deposit barrier material, then the material can be deposited on TSV sidewalls, but thickness variations occur leading to poor adhesion
Solution Approach 1:
The patent replaces the mechanical physical vapor deposition process with a chemical nitridation process. This substitution eliminates the thickness variation problems inherent in PVD by using chemical reactions that uniformly convert the barrier material into a nitrided compound with consistent properties across the entire surface
Solution Approach 2:
The patent changes the deposition mechanism from physical to chemical by using nitridation reactions. This parameter change in the deposition process ensures uniform thickness and composition of the barrier layer, directly improving both manufacturing precision and subsequent adhesion reliability
3Reliability
If barrier material is deposited on TSV sidewalls, then electromigration is prevented, but the barrier material expands and contracts more than silicon causing delamination
Solution Approach 1:
The patent creates a composite nitrided barrier structure that maintains the electromigration prevention function while incorporating nitrogen to reduce thermal expansion mismatch. This composite approach preserves the protective function against electromigration while mitigating the thermal stress that causes delamination
4Productivity
If conventional barrier materials are used, then TSV manufacturing can proceed, but delamination occurs during manufacturing processes
Solution Approach 1:
The patent applies preliminary action by performing nitridation treatment on the barrier material before final TSV assembly and manufacturing steps. This pre-treatment ensures that the barrier layer has optimal adhesion properties beforehand, preventing delamination during subsequent manufacturing processes and maintaining productivity
Solution Approach 2:
The patent changes the chemical state of the barrier material through nitridation, transforming it from a conventional metal or oxide layer to a nitrogen-containing compound. This parameter change improves bonding reliability without adding significant process time, thus maintaining manufacturing efficiency
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 nitrided barrier solution improves the adhesion and reduces electromigration, maintaining structural integrity and electrical performance by addressing thermal expansion mismatches and providing uniform coverage.
Implementation Method 1
A nitrided barrier is formed by reacting a barrier material with reactive nitrogen gas, creating a uniform nitride layer
Implementation Method 2
The difference in the expansion and contraction between the barrier materials and the silicon material can lead to delamination of the barrier material
Data Source
AI summary
Semiconductor device interconnect structures comprising nitrided barriers are disclosed herein. In one embodiment, an interconnect structure includes a conductive material at least partially filling an opening in a semiconductor substrate, and a nitrided barrier between the conductive material and a sidewall in the opening. The nitrided barrier comprises a nitride material and a barrier material, such as tantalum, between the nitride material and the sidewall of the substrate.