Ion Beam Etching for Finer Semiconductor Mask Patterns
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Solution Overview
Problem
The resolution limit of photolithography apparatuses hinders the formation of finer-pitch patterns in semiconductor device manufacturing, making it difficult to produce highly integrated semiconductor devices with advanced features.
Innovation Solution
A method involving the formation of preliminary mask patterns on a substrate, followed by an ion beam etching process using these patterns as an etch mask to create interim-mask patterns of triangular-prism and trapezoidal-prism shapes alternately, which allows for the formation of finer features beyond the resolution limit of conventional photolithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography apparatuses are used for pattern formation, then manufacturing process is simple and efficient, but pattern pitch is limited by resolution limit
Solution Approach 1:
The fabrication process is divided into multiple stages: first forming preliminary mask patterns with conventional photolithography, then using ion beam etching to create interim mask patterns with finer pitch, and finally forming target patterns. This segmentation allows each stage to optimize for its specific function, overcoming the resolution limit of photolithography while maintaining overall process efficiency
Solution Approach 2:
Preliminary mask patterns are formed in advance using photolithography before the ion beam etching process. These preliminary patterns serve as templates that guide the subsequent ion beam etching to create the final fine-pitch patterns, enabling the system to benefit from both conventional lithography and advanced etching techniques
2Manufacturing precision
If ion beam etching is used to form fine patterns, then pattern pitch is improved beyond photolithography resolution limit, but fabrication process complexity increases
Solution Approach 1:
Interim mask patterns are introduced as intermediary structures between the preliminary mask patterns and the final target patterns. These interim patterns, formed by ion beam etching with triangular-prism and trapezoidal-prism shapes, serve as intermediate templates that enable the transfer of fine-pitch features to the final structure while managing process complexity
Solution Approach 2:
The invention changes the etching parameters and methodology from conventional photolithography-based etching to ion beam etching. This parameter change enables the formation of patterns with pitch below the photolithography resolution limit by utilizing the directional and high-precision nature of ion beam irradiation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables the fabrication of semiconductor devices with finer pitches, overcoming the limitations of traditional photolithography and allowing for more advanced and integrated semiconductor designs.
Implementation Method 1
An ion beam etching process is performed on the upper mask layer using the plurality of preliminary mask patterns as an etch mask to form a first preliminary-interim-mask pattern and a pair of second preliminary-interim-mask patterns
Data Source
AI summary
An etching target layer is formed on a substrate. An upper mask layer is formed on the etching target layer. A plurality of preliminary mask patterns is formed on the upper mask layer. The plurality of preliminary mask patterns is arranged at a first pitch. Two neighboring preliminary mask patterns of the plurality of preliminary mask patterns define a preliminary opening. An ion beam etching process is performed on the upper mask layer using the plurality of preliminary mask patterns as an etch mask to form a first preliminary-interim-mask pattern and a pair of second preliminary-interim-mask patterns. The first preliminary-interim-mask pattern is formed between one of the pair of second preliminary-interim-mask patterns and the other of the pair of second preliminary-interim-mask patterns.