Semiconductor Fin Structure Separator Insulating Layer
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Solution Overview
Problem
As semiconductor device dimensions decrease, self-aligned contact structures face challenges in maintaining electrical isolation between source/drain contacts and gate electrodes due to thinner sidewall spacers, leading to potential short circuits and increased density, which complicates the manufacturing process.
Innovation Solution
The method involves forming a separator insulating layer between the gate structures and source/drain regions, allowing for self-aligned contact formation through a gate cutting process, which reduces circuit size and suppresses short circuits by using a separator made of insulating material different from the isolation and interlayer dielectric layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If device dimensions are decreased to increase device density, then productivity is improved, but sidewall spacer thickness becomes thinner which causes short circuit between source/drain contact and gate electrodes, worsening reliability
Solution Approach 1:
A separator insulating layer is introduced as an intermediary component between the gate structure and source/drain contact. This separator layer with different etch selectivity enables independent patterning and provides additional electrical isolation, preventing short circuits while allowing continued scaling for improved device density.
Solution Approach 2:
The interlayer dielectric layer is segmented into multiple functional layers: a first interlayer dielectric layer forming the main contact structure, and a second interlayer dielectric layer forming the separator. This segmentation allows each layer to be optimized independently - the first layer for contact formation and the second layer for electrical isolation and gate protection.
2Reliability
If separator insulating layer and gate cutting process are used to improve electrical isolation, then reliability is improved, but device complexity increases
Solution Approach 1:
The separator insulating layer serves dual functions: it provides electrical isolation between gate and contact, and simultaneously acts as a self-aligned mask during the gate cutting process. The gate cutting process automatically defines the contact opening position using the separator layer itself, eliminating the need for separate alignment steps and reducing overall process complexity despite the additional layer.
Data Source
AI summary
A semiconductor device includes a fin structure, first and second gate structures, a source/drain region, a source/drain contact, a separator, a plug contacting the source/drain contact and a wiring contacting the plug. The fin structure protrudes from an isolation insulating layer and extends in a first direction. The first and second gate structures are formed over the fin structure and extend in a second direction crossing the first direction. The source/drain region is disposed between the first and second gate structures. The interlayer insulating layer is disposed over the fin structure, the first and second gate structures and the source/drain region. The first source/drain contact is disposed on the first source/drain region. The separator is disposed adjacent to the first source/drain contact layer. Ends of the first and second gate structures and an end of the source drain contact are in contact with a same face of the separator.