Open TSV Sublayer Structure for Stress Crack Prevention
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Solution Overview
Problem
Conventional through-substrate via (TSV) structures face high stress gradients due to materials with distinct properties, leading to increased cracking probability, which conventional stress compensation methods exacerbate.
Innovation Solution
Implementing an insulation and capping layer with sublayers of different intrinsic stress types, where one sublayer extends into the trench and another is adjacent to it, compensating overall stress without significant strain or cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If conventional stress compensation methods using high stress insulation layer are employed, then stress in remaining layers is compensated, but cracking probability inside the trench of TSV increases
Solution Approach 1:
The insulation layer is divided into multiple sublayers (first insulation sublayer, second insulation sublayer, third insulation sublayer) with different stress characteristics. This segmentation allows each sublayer to contribute differently to stress management, providing both stress compensation and crack prevention functionality that a single homogeneous layer cannot achieve.
Solution Approach 2:
Different sublayers are assigned different stress properties tailored to specific locations and functions. The first insulation sublayer has compressive stress to prevent tensile cracking, the second has tensile stress for stress compensation, and the third has compressive stress for surface protection. This local differentiation of material properties optimizes both stress management and reliability.
2Reliability
If different material layers with distinct material properties are employed in TSV, then electrical insulation and structural functionality are achieved, but large stress gradients between layers are generated
Solution Approach 1:
The patent changes the stress parameter (intrinsic stress state) across different insulation sublayers to create a gradient that compensates for stress from other TSV components. By carefully controlling the stress magnitude and sign in each sublayer, the overall stress distribution is optimized to minimize damaging stress concentrations while maintaining electrical insulation.
Solution Approach 2:
The insulation structure is designed as a composite of multiple sublayers with different stress characteristics rather than a single homogeneous material. This composite approach allows the system to achieve both electrical insulation and stress management functions by combining materials with complementary properties.
Data Source
Figure 1~2
Figure 3
AI summary
An open through-substrate via (1), TSV, comprises an insulation layer (20) disposed adjacent to at least a portion of side walls (15) of a trench (14) and to a surface (13) of a substrate body (10). The TSV further comprises a metallization layer (30) disposed adjacent to at least a portion of the insulation layer (20) and to at least a portion of a bottom wall (16) of said trench (14), a redistribution layer (40) disposed adjacent to at least a portion of the metallization layer (30) and a portion of the insulation layer (20) disposed adjacent to the surface (13), and a capping layer (50) disposed adjacent to at least a portion of the metallization layer (30) and to at least a portion of the redistribution layer (40). The insulation layer (20) and/or the capping layer (50) comprise sublayers (21, 22, 51, 52) that are distinct from each other in terms of material properties. A first of the sublayers (21, 51) is disposed adjacent to at least a portion of the side walls (15) and to at least a portion of the surface (13) and a second of the sublayers (22, 52) is disposed adjacent to at least a portion of the surface (13).