FinFET Patterning Using Dual Photomasks
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Solution Overview
Problem
Conventional methods for manufacturing semiconductor devices with fin structures, such as FinFETs, require multiple photomasks and additional processes, leading to increased manufacturing costs and complexity, especially when scaling down to 65 nm and below.
Innovation Solution
A method using only two photomasks to form both fin and feature structures through a sidewall image transfer process, where a first photomask forms sacrificial blocks and spacers, and a second photomask defines feature masks and fin cutting masks, allowing for the simultaneous formation of fin and feature spacers without the need for extra photomasks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to form fin structures with multiple photomasks, then the fin structure can be formed with good precision, but the manufacturing cost increases and process complexity increases
Solution Approach 1:
The patent combines the formation of fin structures and feature structures into a single integrated process using one photomask. The photomask simultaneously defines both the fin pattern and the feature pattern, merging two separate patterning operations into one, thereby reducing process complexity while maintaining manufacturing precision
Solution Approach 2:
The single photomask serves multiple functions: it defines the fin structure pattern, defines the feature structure pattern, and provides alignment references for both. This multi-functional approach eliminates the need for separate photomasks for fins and features, reducing overall device complexity
2Manufacturing precision
If extra photomasks are used to form feature structures, then the feature structures can be precisely defined, but the manufacturing cost increases
Solution Approach 1:
The patent merges the patterning of fin structures and feature structures into a single photolithography step using one photomask. This consolidation eliminates the need for additional photomasks and alignment processes, reducing manufacturing cost while maintaining the precision needed for feature structure definition
Solution Approach 2:
The single photomask is designed to serve multiple purposes: defining fin patterns, defining feature patterns, and providing alignment references. This universal approach allows precise feature structure definition without requiring extra photomasks, thereby reducing manufacturing cost
Data Source
AI summary
The present invention provides a method of manufacturing a semiconductor device including using a first photomask to form a sacrificial block on a hard mask layer in a first region, a first dummy pattern on the sacrificial block, a first spacer on sidewalls of the sacrificial block and a second spacer in a second region; using a second photomask to form a feature mask on the first dummy pattern and a fin cutting mask on the second spacer; and performing a fin cutting process to remove a portion of the first dummy pattern, a portion of the sacrificial block underlying the portion of the first dummy pattern and the first spacer to form a feature spacer and to remove a portion of the second spacer without being covered with the fin cutting mask to form a fin spacer.