Backside Power Rail Layout With Tapered Via Contact
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Solution Overview
Problem
Existing integrated circuit devices face challenges in achieving high-capacity and high-integration while maintaining efficient electrical characteristics and reliability, particularly due to limitations in wiring structures and power rail designs.
Innovation Solution
The integrated circuit device incorporates a substrate with fin-type active regions, a device isolation layer, a via power rail extending through the isolation layer, and a backside power rail connected to the via power rail, featuring inclined surfaces on the via power rail to enhance electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional via power rail with vertical side walls is used, then the manufacturing process is simple, but the contact area with the backside power rail is limited and electrical resistance is high
Solution Approach 1:
The via power rail is designed with curved side walls instead of vertical walls, creating an inclined surface that increases the contact area with the backside power rail. This curvature modification improves electrical characteristics by reducing resistance while maintaining manufacturing feasibility through standard etching processes that can produce tapered profiles.
Solution Approach 2:
The geometry of the via power rail is changed by modifying the wall angle to create an inclined profile. This parameter change increases the surface area for electrical contact with the backside power rail, thereby improving electrical characteristics without fundamentally changing the manufacturing approach.
2Reliability
If the contact area between via power rail and backside power rail is increased, then electrical resistance is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The curved side walls of the via power rail naturally increase contact area while the taper angle can be controlled within standard manufacturing tolerances. This approach achieves improved electrical resistance without requiring ultra-precise manufacturing, as the curved profile can be formed by conventional etching processes.
Data Source
AI summary
An integrated circuit device includes: a substrate including a backside surface; fin-type active regions protruding from the substrate such as to define a trench region on the substrate; a device isolation layer covering, in the trench region, a side wall of each of the fin-type active regions; a via power rail vertically extending through the device isolation layer between the fin-type active regions; and a backside power rail vertically extending through the substrate and connected to one end of the via power rail, wherein the via power rail includes a first portion connected to the backside power rail and a second portion on the first portion, and wherein two side walls of the first portion each include an inclined surface that is inclined such as to come closer to the pair of fin-type active regions as the two side walls approach the backside power rail.