Dummy Stacked TSV Structures for Moisture Outgassing
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Solution Overview
Problem
Conventional methods for forming Through-Silicon Vias (TSVs) in semiconductor substrates face challenges in effectively removing moisture absorbed during the TSV process, which can lead to dielectric degradation and reduced efficiency.
Innovation Solution
The formation of dummy stacked structures encircling the TSVs, which act as outgassing tunnels to dissipate moisture during a baking process and prevent lateral moisture intrusion, is introduced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional TSV formation methods are used, then the TSV structure is formed, but moisture remains trapped in the dielectric layers causing dielectric degradation
Solution Approach 1:
The patent extracts moisture from the dielectric layers by creating dedicated outgassing pathways. Dummy stacked structures are formed around TSVs to provide tunnels that extract trapped moisture during baking processes, preventing dielectric degradation while maintaining TSV functionality.
Solution Approach 2:
The dummy stacked structures serve as intermediary elements between the TSVs and the surrounding dielectric layers. These structures act as mediators that facilitate moisture removal by providing controlled pathways for water vapor to escape during thermal processing, thereby protecting the dielectric integrity.
2Object-affected harmful factors
If dummy stacked structures are added around TSVs, then moisture removal effectiveness is enhanced, but device complexity increases
Solution Approach 1:
The patent merges the formation of dummy stacked structures with existing TSV fabrication processes. The dummy structures are created using similar deposition and etching steps as the TSVs themselves, combining multiple functions into a unified process flow that reduces overall complexity despite adding functional elements.
Solution Approach 2:
The dummy stacked structures serve multiple functions: they act as outgassing tunnels for moisture removal, provide structural support around TSVs, and maintain dielectric layer integrity. This multi-functionality justifies the added structural elements by delivering multiple benefits from a single feature addition.
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 dummy stacked structures enhance the effectiveness of moisture removal, reducing dielectric degradation and maintaining the integrity of the semiconductor substrate.
Implementation Method 1
The dummy stacked structures are formed in the dielectric layers, and function as outgassing tunnels for dissipating water that has been absorbed in the TSV openings during a baking process
Implementation Method 2
function as outgassing tunnels for dissipating water that has been absorbed in the TSV openings during a baking process and to prevent lateral water intrusion into the TSV openings
Data Source
AI summary
A method includes forming a plurality of low-k dielectric layers over a semiconductor substrate, forming a first plurality of dummy stacked structures extending into at least one of the plurality of low-k dielectric layers, forming a plurality of non-low-k dielectric layers over the plurality of low-k dielectric layers, and forming a second plurality of dummy stacked structures extending into the plurality of non-low-k dielectric layers. The second plurality of dummy stacked structures are over and connected to corresponding ones of the first plurality of dummy stacked structures. The method further includes etching the plurality of non-low-k dielectric layers, the plurality of low-k dielectric layers, and the semiconductor substrate to form a via opening. The via opening is encircled by the first plurality of dummy stacked structures and the second plurality of dummy stacked structures. The via opening is then filled to form a through-via.