Semiconductor Patterning via Spacer Formation
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Solution Overview
Problem
Current photolithographic techniques face limitations in reducing feature size due to minimum pitch constraints, making it challenging to achieve different levels of pitch multiplication across various regions of a semiconductor substrate efficiently without introducing complexity into the fabrication process.
Innovation Solution
A method involving the formation of multiple patterns with varying pitches on a semiconductor base using a stack of materials, including silicon nitride and oxynitride layers, where masking features are trimmed and spacers are formed to achieve pitch-doubling and pitch-quadrupling, allowing for the combination of common process steps across different regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pitch-doubling is performed along one region of a semiconductor substrate and pitch-quadrupling along another region, then different levels of pitch multiplication are achieved across different regions, but the fabrication process becomes more complex
Solution Approach 1:
The semiconductor substrate is divided into different regions (first region and second region) that receive different pitch multiplication treatments. The method segments the fabrication process into region-specific steps, allowing pitch-doubling in one region and pitch-quadrupling in another, thereby achieving adaptability while managing complexity through structured division
Solution Approach 2:
The patent employs universal process steps that can serve multiple functions across different regions. By using common masking, etching, and spacer formation procedures that work for both pitch-doubling and pitch-quadrupling, the method achieves multi-functionality, reducing the need for entirely separate process sequences and thereby limiting complexity growth
2Ease of manufacture
If common process steps are combined for different levels of pitch multiplication, then fabrication economy is improved, but other complexities are introduced into the fabrication process
Solution Approach 1:
The patent merges common process steps for different pitch multiplication levels, combining masking, etching, and spacer formation into unified sequences that serve both pitch-doubling and pitch-quadrupling regions. This merging improves fabrication economy by reducing redundant steps while the structured combination prevents excessive complexity through systematic integration
3Manufacturing precision
If photolithographic techniques are used to reduce feature size, then integrated circuit density is improved, but minimum pitch constraints limit further reduction
Solution Approach 1:
The patent transitions from direct photolithographic patterning to a multi-dimensional approach using spacer formation. By depositing conformal spacer layers around photoresist features and then removing the photoresist, the method creates patterns at dimensions smaller than the photolithographic limit, effectively moving the patterning problem into a different dimensional regime (from planar photolithography to vertical spacer deposition and lateral pattern transfer)
Solution Approach 2:
The method performs preliminary actions by forming photoresist features at larger dimensions that are within photolithographic capabilities, then uses these as templates for subsequent spacer formation. This preliminary patterning at relaxed dimensions allows the final high-density pattern to be achieved through spacer-based multiplication rather than direct photolithography, bypassing minimum pitch constraints
Data Source
AI summary
Some embodiments include methods of patterning a base. First and second masking features are formed over the base. The first and second masking features include pedestals of carbon-containing material capped with silicon oxynitride. A mask is formed over the second masking features, and the silicon oxynitride caps are removed from the first masking features. Spacers are formed along sidewalls of the first masking features. The mask and the carbon-containing material of the first masking features are removed. Patterns of the spacers and second masking features are transferred into one or more materials of the base to pattern said one or more materials. Some embodiments include patterned bases.