Integrated Circuit Isolation Area for Water Vapor Permeation
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Solution Overview
Problem
Conventional through silicon via (TSV) technology in integrated circuits faces challenges with water vapor permeation through dielectric materials with low dielectric constants, leading to increased dielectric constant, degradation of time-dependent dielectric breakdown (TDDB) characteristics, oxidation of metal routing, and delamination.
Innovation Solution
Incorporating a dense material with lower porosity as an isolation area surrounding the via within the redistribution layer, which prevents water vapor from permeating into the dielectric layer and metal routing, thereby maintaining the low dielectric constant and improving signal transmission speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a dielectric material with a micropore structure is used to reduce same-layer capacitance, then the dielectric constant is reduced and operating speed is improved, but water vapor easily permeates into the redistribution layer causing dielectric constant increase and TDDB degradation
Solution Approach 1:
The patent implements a nested structure where a first water vapor isolation structure is formed within the micropore dielectric material, and a second water vapor isolation structure is formed around the via. This nested arrangement creates multiple barriers against water vapor permeation while preserving the low-dielectric-constant properties of the micropore material, thereby resolving the contradiction between speed improvement and reliability degradation.
Solution Approach 2:
The water vapor isolation structures act as intermediary barriers between the external environment and the micropore dielectric material. These isolation structures prevent water vapor from directly contacting and permeating into the micropore material, thus protecting the TDDB characteristics while maintaining the speed benefits of the low-dielectric-constant material.
2Reliability
If a metal water vapor isolation ring is manufactured around the TSV to prevent water vapor permeation, then water vapor protection is improved, but the area of the integrated circuit increases
Solution Approach 1:
The patent applies water vapor isolation structures locally at critical positions where water vapor permeation is most problematic (around vias and within micropore regions), rather than implementing a comprehensive metal isolation ring around the entire TSV. This localized approach provides effective water vapor protection while minimizing the additional area occupied in the integrated circuit.
Solution Approach 2:
The patent uses composite material structures combining micropore dielectric material with water vapor isolation materials in specific configurations. This composite approach achieves effective water vapor barrier properties without requiring the extensive metal isolation ring structure, thus reducing the overall area impact while maintaining reliability.
3Ease of manufacture
If wet cleaning is performed on the dielectric material after etching, then residue is removed, but water molecules permeate into the redistribution layer causing oxidation of metal routing and delamination
Solution Approach 1:
The patent implements water vapor isolation structures before the wet cleaning process is applied. These pre-formed isolation structures create a protective barrier that prevents water molecules from the cleaning process from permeating into the redistribution layer and causing metal routing oxidation, thus enabling effective cleaning without the harmful side effects.
Solution Approach 2:
The water vapor isolation structures are formed in advance before subsequent processing steps that involve water or moisture. This preliminary action ensures that when wet cleaning or other moisture-exposed processes are performed later, the isolation structures are already in place to protect the metal routing from oxidation and delamination.
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 effectively prevents water vapor from entering the dielectric layer, resolving issues of increased dielectric constant, TDDB degradation, metal routing oxidation, and delamination, while maintaining the low dielectric constant for improved signal transmission speed.
Implementation Method 1
prevents water vapor from permeating into the dielectric layer and metal routing
Data Source
AI summary
An integrated circuit includes: a silicon substrate, and a redistribution layer located on the silicon substrate, where the redistribution layer includes metal routing and a dielectric layer of a first material. An isolation area that runs through the redistribution layer is disposed in the redistribution layer. The isolation area includes a second material. A porosity of the second material is less than a porosity of the first material. A via is disposed inside the isolation area, and the second material surrounds a part of the via. The second material may be a dense material, such that water vapor in the via can be effectively isolated.