Through-Via Insulation Thickness Control for TSV Reliability
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Solution Overview
Problem
Existing semiconductor device fabrication methods face challenges in ensuring the reliability and yield of through-silicon vias (TSVs) due to contamination and particle issues caused by exposed TSVs during the via-insulating layer etching process.
Innovation Solution
A method involving the formation of a via-insulating layer with a thicker bottom surface thickness and a thinner sidewall thickness, using flowable chemical vapor deposition (FCVD) layers, and subsequent recessing of the substrate to expose the through-via, while maintaining electrical insulation and preventing substrate exposure, is employed to improve the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the via-insulating layer is etched to recess the substrate, then the through-via can be exposed for electrical connection, but the exposed through-via becomes a contamination or particle source causing process errors
Solution Approach 1:
The via-insulating layer is formed in advance with a thicker bottom surface thickness before substrate recessing. This preliminary thicker layer ensures that even after etching and recessing, the through-via remains covered and does not become exposed to cause contamination or particle issues, while still allowing precise electrical connection when needed.
Solution Approach 2:
The via-insulating layer is designed with non-uniform thickness: a first (thicker) thickness on the bottom surface of the via-hole and a second (thinner) thickness on the inner sidewall. This local quality differentiation allows the bottom surface to provide sufficient coverage preventing exposure and contamination, while the thinner sidewall portion maintains electrical insulation without excessive material.
2Reliability
If the via-insulating layer thickness is increased to prevent through-via exposure, then contamination is prevented, but the electrical insulation effectiveness may be compromised
Solution Approach 1:
The via-insulating layer employs different thicknesses at different locations: a thicker first thickness on the bottom surface to prevent through-via exposure and contamination, and a thinner second thickness on the inner sidewall to maintain appropriate electrical insulation. This local quality variation optimizes both contamination prevention and electrical insulation effectiveness.
Solution Approach 2:
The via-insulating layer is effectively segmented into two functional regions: the bottom surface portion with greater thickness for mechanical coverage and contamination prevention, and the sidewall portion with lesser thickness for electrical insulation. This segmentation allows each region to perform its specific function optimally.
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 enhances the reliability and yield of semiconductor devices by preventing contamination and particle exposure, ensuring effective electrical insulation and minimizing process errors, thereby improving the electric characteristics of the devices.
Implementation Method 1
converting the flowable layer into a first flowable chemical vapor deposition layer having the first thickness on the bottom surface of the via-hole
Data Source
AI summary
The inventive concept provides semiconductor devices having through-vias and methods for fabricating the same. The method may include forming a via-hole opened toward a top surface of a substrate and partially penetrating the substrate, forming a via-insulating layer having a first thickness on a bottom surface of the via-hole and a second thickness smaller than the first thickness on an inner sidewall of the via-hole, forming a through-via in the via-hole which the via-insulating layer is formed in, and recessing a bottom surface of the substrate to expose the through-via. Forming the via-insulating layer may include forming a flowable layer on the substrate, and converting the flowable layer into a first flowable chemical vapor deposition layer having the first thickness on the bottom surface of the via-hole.