Semiconductor Contact Fabrication via Orthogonal Spacer Patterning
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Solution Overview
Problem
Current methods for fabricating semiconductor devices, such as double-patterning technology, face challenges in achieving uniformity and reliability due to asymmetric patterns and complex processing steps, which can lead to inefficiencies and reduced operation reliability.
Innovation Solution
A method involving the formation of multiple mask patterns and spacers with specific etching processes to create contact patterns and holes, using materials with varying etch selectivity, and the strategic use of sacrificial films to simplify the fabrication process and improve pattern uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If double-patterning technology is applied to fabricate patterns in highly integrated semiconductor devices, then pattern precision is improved, but process complexity increases and asymmetric patterns are generated
Solution Approach 1:
The fabrication process is divided into multiple sequential stages: first forming mask patterns in a first direction, then forming spacers on side walls, followed by forming mask patterns in a second direction perpendicular to the first. This segmentation allows complex contact hole patterns to be created through simpler, more uniform sequential steps rather than attempting to form all patterns simultaneously, thereby improving precision while managing process complexity.
Solution Approach 2:
Spacer structures are formed in advance on the side walls of mask patterns before the final etching step. These pre-formed spacers serve as etch masks that define the contact hole positions with high precision. By performing this preliminary action, the method ensures uniform pattern formation while avoiding the asymmetric issues that arise in conventional double-patterning approaches.
2Manufacturing precision
If double-patterning technology is used to improve pattern uniformity, then manufacturing precision is improved, but operation reliability decreases due to asymmetric features
Solution Approach 1:
The method deliberately employs orthogonal directions (first direction and second direction perpendicular to it) for forming mask patterns and spacers. This asymmetric approach in terms of directionality actually produces symmetric contact hole patterns because the orthogonal arrangement ensures uniform spacing and positioning from all sides, eliminating the asymmetric features that harm reliability in conventional methods.
Solution Approach 2:
The fabrication process transitions from two-dimensional planar patterning to three-dimensional spacer formation on vertical side walls, then combines patterns from two orthogonal directions. This dimensional transition and combination create highly uniform contact hole patterns with improved reliability, as the vertical spacer formation ensures consistent pattern dimensions regardless of lateral variations.
3Device complexity
If conventional fabrication methods are used, then process complexity is low, but manufacturing precision and pattern uniformity are insufficient for highly integrated devices
Solution Approach 1:
The fabrication process is divided into multiple sequential stages: first forming mask patterns in a first direction, then forming spacers on side walls, followed by forming mask patterns in a second direction perpendicular to the first. This segmentation allows complex contact hole patterns to be created through simpler, more uniform sequential steps rather than attempting to form all patterns simultaneously, thereby improving precision while managing process complexity.
Solution Approach 2:
Spacer structures serve as intermediary elements between the mask patterns and the final contact holes. These spacers are formed on the side walls of mask patterns and then used as etch masks to define the contact hole positions. This intermediary step enables precise pattern transfer while maintaining uniformity, bridging the gap between simple mask formation and precise contact hole creation.
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 approach enhances the efficiency and reliability of semiconductor device fabrication by reducing the complexity of the process, preventing asymmetric features in contact holes, and improving the uniformity of patterns, thereby increasing the operational reliability of the devices.
Implementation Method 1
etching the first film using the first spacer and the second spacer as etch masks to form a contact pattern
Implementation Method 2
removing the first and second spacers to expose the contact pattern
Data Source
AI summary
A method for fabricating a semiconductor device includes forming a first mask pattern on a first film to extend in a first direction, forming a first spacer on either side wall of the first mask pattern, forming a second film to cover the first spacer and the first film, and forming a second mask pattern on the second film. The second mask pattern extends in a second direction different from the first direction. The method further includes forming a second spacer on either side wall of the second mask pattern, etching the first film using the first spacer and the second spacer as etch masks to form a contact pattern, and removing the first and second spacers to expose the contact pattern.