Reentrant TSV Structure to Protect Dielectric Liner During Etching
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Solution Overview
Problem
Existing through-substrate-via (TSV) fabrication processes cause damage to the dielectric liner due to etching, leading to insufficient insulation and reduced reliability of integrated chips.
Innovation Solution
The integration of a TSV with a reentrant profile that increases in width as it extends through the substrate, laterally separating the dielectric liner sidewalls from the etchant, thereby protecting the liner during fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional TSV fabrication process is used, then the TSV can be formed to connect conductive features, but the dielectric liner is damaged by etching, leading to insufficient insulation and reduced reliability
Solution Approach 1:
A mandrel structure is formed beforehand within the TSV opening before the etching process. This mandrel serves as a physical barrier that prevents etchant from contacting and damaging the dielectric liner during the etching process, thereby protecting the liner while still allowing the TSV to be formed
Solution Approach 2:
The mandrel acts as an intermediary element between the etchant and the dielectric liner. It absorbs or blocks the harmful effect of the etchant, preventing direct contact with the liner while allowing the etching process to proceed to form the TSV
2Reliability
If the TSV width is increased to improve electrical connectivity, then conductivity is enhanced, but the dielectric liner becomes more vulnerable to etching damage
Solution Approach 1:
The mandrel is formed in advance within the TSV opening, establishing a protective framework before etching begins. This allows the TSV to achieve the desired width for good electrical connectivity while the mandrel simultaneously protects the liner from etching damage throughout the process
3Productivity
If the etching process is made more aggressive to improve manufacturing efficiency, then productivity increases, but damage to the dielectric liner worsens
Solution Approach 1:
The mandrel serves as a protective intermediary that enables aggressive etching conditions to be used without damaging the dielectric liner. The mandrel absorbs the full force of the etchant, allowing faster, more aggressive etching processes to be employed while the liner remains protected
Solution Approach 2:
By forming the mandrel structure beforehand, the system enables more aggressive etching parameters to be used from the start, improving manufacturing efficiency without compromising liner integrity throughout the etching process
Data Source
AI summary
The present disclosure, in some embodiments, relates an integrated chip. The integrated chip includes a semiconductor substrate. A liner is arranged along one or more interior sidewalls of the semiconductor substrate. The liner vertically extends between a first side of the semiconductor substrate and a second side of the semiconductor substrate opposing the first side. A conductive material is arranged between interior sidewalls of the liner. The liner has a vertically extending segment and a horizontally extending segment protruding outward from the vertically extending segment. The horizontally extending segment is arranged at least partially vertically outside of the semiconductor substrate.