Single Diffusion Break Isolation Using Universal Masking
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Solution Overview
Problem
Conventional methods for forming integrated circuit (IC) structures with isolation features require a large number of masks, limiting the ability to create single diffusion breaks (SDB) that abut end isolation regions due to design rule constraints and structural differences at various locations, preventing the use of a single mask for multiple types of isolation regions.
Innovation Solution
A method involving a plurality of fins and shallow trench isolations (STIs) on a substrate, where a masking layer is formed, and trenches are created to expose fins and STIs, allowing for the formation of insulators without exposing the substrate, enabling the creation of single diffusion breaks and end isolation regions with reduced mask usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to form multiple types of isolation regions, then each isolation structure can be formed with proper protection, but a large number of masks are required
Solution Approach 1:
A single mask structure is designed to perform multiple functions: it defines both the single diffusion break region and the end isolation region, and also serves as a protective layer for previously-formed structures. This universal mask approach eliminates the need for separate masks for each isolation type, reducing the total mask count while maintaining proper isolation structure formation.
Solution Approach 2:
The patent combines the formation of multiple isolation regions (SDB and end isolation) into a single processing step using one mask. The mask is positioned to simultaneously expose both the fin region for SDB formation and the STI region for end isolation formation, merging what would traditionally require separate masking and etching operations into one unified process.
2Adaptability or versatility
If structural features are added to protect previously-formed structures, then isolation regions can be formed at different locations, but the device complexity increases
Solution Approach 1:
The masking layer serves multiple protective and definitional functions simultaneously. It acts as a protective barrier for previously-formed structures while also defining the boundaries of both SDB and end isolation regions. This multi-functionality eliminates the need for additional protective structural features, reducing device complexity while maintaining adaptability for different isolation placements.
3Productivity
If a single mask is used to form multiple isolation regions, then mask quantity is reduced, but design rule constraints and structural differences must be accommodated
Solution Approach 1:
The masking layer is positioned at different locations with different dimensions to accommodate local structural requirements. The mask extends over the fin region to define the SDB boundary and over the STI region to define the end isolation boundary, with each portion optimized for its specific location. This local quality approach allows a single mask to satisfy design rules at different positions while maintaining manufacturing precision.
Data Source
AI summary
The disclosure provides integrated circuit (IC) structures with single diffusion break (SDB) abutting end isolation regions, and methods of forming the same. An IC structure may include: a plurality of fins positioned on a substrate; a plurality of gate structures each positioned on the plurality of fins and extending transversely across the plurality of fins; an insulator region positioned on the plurality of fins and laterally between the plurality of gate structures; at least one single diffusion break (SDB) positioned within the insulator region and one of the plurality of fins, the at least one SDB region extending from an upper surface of the substrate to an upper surface of the insulator region; and an end isolation region abutting a lateral end of the at least one SDB along a length of the plurality of gate structures, the end isolation region extending substantially in parallel with the plurality of fins.