Redistributed Contact Layer for Low Resistance Interconnects
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Solution Overview
Problem
As semiconductor devices shrink, forming precise smaller contact holes and contact plugs on gates or source and drain regions while minimizing contact resistance becomes a challenge in achieving denser and faster integrated circuits.
Innovation Solution
A semiconductor transistor device with a redistributed contact layer (RCL) that extends from the active area to the trench isolation region, allowing for a contact plug to be electrically connected to the gate, source, or drain doping regions, facilitating improved interconnectivity and reducing contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional contact structures are used in shrinking semiconductor devices, then device density increases, but contact resistance increases and manufacturing precision deteriorates
Solution Approach 1:
The contact structure is divided into multiple segments: a contact hole through the insulating cap layer, a contact plug filling the contact hole, and a redistributed contact layer extending from the active area to the trench isolation region. This segmentation allows each component to be optimized independently, enabling precise formation of smaller contact holes while maintaining low contact resistance through the extended RCL pathway.
Solution Approach 2:
The redistributed contact layer extends in the lateral dimension from the active area to the trench isolation region, adding a horizontal component to the contact path. This dimensional extension allows the contact structure to achieve both small vertical contact hole dimensions and low resistance by distributing the contact function across a larger lateral area.
2Area of moving object
If device dimensions are reduced to increase density, then integrated circuit density improves, but contact resistance increases
Solution Approach 1:
While the vertical device dimensions are reduced to increase density, the redistributed contact layer extends laterally to the trench isolation region, compensating for the reduced contact area by distributing the contact function across a larger horizontal dimension, thereby maintaining low contact resistance.
Solution Approach 2:
The redistributed contact layer acts as an intermediary structure that bridges the gap between the shrinking contact plug and the underlying doping regions. It provides an extended conductive pathway that mediates the electrical connection, ensuring low contact resistance even as the direct contact area is reduced.
3Ease of manufacture
If conventional contact plugs are formed on gates or source/drain regions, then device functionality is achieved, but contact resistance cannot be minimized
Solution Approach 1:
The contact structure is segmented into a contact plug formed by filling a contact hole through the insulating cap layer, and a separate redistributed contact layer formed subsequently. This segmentation allows the contact plug to be precisely formed for ease of manufacture, while the extended RCL provides the low-resistance pathway that conventional single-structure contacts cannot achieve.
Data Source
AI summary
A semiconductor transistor device includes a substrate having an active area and a trench isolation region surrounding the active area, a gate oxide layer, a gate, a spacer on a sidewall of the gate, a doping region on one side of the gate, an insulating cap layer covering the gate, the spacer and the doping region, and a redistributed contact layer (RCL) on the insulating cap layer. The RCL extends from the active area to the trench isolation region. A contact plug is disposed above the trench isolation region and is electrically connected to the gate or the doping region through the RCL.