Vertical Connection Structure for Low-Resistance Semiconductor Interconnects
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Solution Overview
Problem
The integration of high-density semiconductor devices poses challenges in maintaining critical dimensions and reducing contact resistance while ensuring adequate thermal dissipation and warpage control.
Innovation Solution
A vertical connection structure with a first portion having a smaller lateral size penetrating through the substrate to the frontside and a second portion with a larger lateral size extending to the backside, connected by a ring wall to maintain integration level and reduce contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the lateral size of the connection structure is reduced to maintain critical dimensions, then integration density is improved, but contact resistance increases
Solution Approach 1:
The connection structure transitions from a uniform two-dimensional cross-section to a three-dimensional structure with varying lateral dimensions along the vertical axis. The first portion has a smaller lateral size for maintaining critical dimensions at the frontside, while the second portion has a larger lateral size for reducing contact resistance at the backside, effectively using the vertical dimension to resolve the contradiction.
Solution Approach 2:
The connection structure is divided into two distinct portions: a first portion with smaller lateral dimensions for precision and integration density, and a second portion with larger lateral dimensions for lower contact resistance. This segmentation allows each portion to optimize for its specific function without compromising the other.
2Reliability
If the lateral size of the connection structure is increased to reduce contact resistance, then reliability is improved, but critical dimension control deteriorates
Solution Approach 1:
The solution moves beyond uniform two-dimensional scaling by introducing vertical dimensionality variation. The connection structure's lateral size changes along the vertical axis, allowing small lateral dimensions at the frontside for critical dimension control and large lateral dimensions at the backside for reduced contact resistance.
Solution Approach 2:
Different portions of the connection structure have different lateral dimensions tailored to their specific functional requirements. The first portion has smaller lateral size optimized for critical dimension maintenance, while the second portion has larger lateral size optimized for contact resistance reduction, applying local quality differentiation to resolve the contradiction.
3Productivity
If high-density integration is achieved by reducing device sizes, then productivity is improved, but thermal dissipation and warpage control become more difficult
Solution Approach 1:
The connection structure utilizes vertical dimensionality to provide thermal management benefits. The larger lateral size of the second portion at the backside creates an expanded thermal pathway and increased surface area for heat dissipation, counteracting the thermal challenges of high-density integration without compromising the small critical dimensions needed for productivity.
Data Source
AI summary
A semiconductor device includes a substrate, an interconnect, and a vertical connection structure. The substrate has a front-side and a back-side. The interconnect is disposed over the front-side of the substrate. The vertical connection structure is embedded in the interconnect and penetrates through the substrate, and the vertical connection structure includes a first portion and a second portion. The first portion is embedded inside the interconnect and further extends into the substrate. The second portion is disposed in the substrate and extends from the back-side to the first portion, and the second portion is in contact with the first portion. An aspect ratio of the second portion is less than an aspect ratio of the first portion.