Cross Pitch Doubled Patterning for Semiconductor Contact Holes
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Solution Overview
Problem
Current semiconductor manufacturing processes require multiple film stacks and planarization steps to achieve fine patterns, leading to high aspect ratios and increased complexity, cost, and time due to the need for multiple layers and steps.
Innovation Solution
A cross pitch doubled patterning method involving a carbon layer, a dielectric anti-reflective coating (DARC) film, and an antireflective layer, which are stacked and etched selectively to form contact holes without the need for multiple layers or planarization, using Atomic Layer Deposition and photoresist trimming to create double pitch patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple film stacks and planarization steps are used to achieve fine patterns, then manufacturing precision is improved, but device complexity and process time increase
Solution Approach 1:
The patent extracts and eliminates the planarization step from the conventional multi-layer patterning process. By using a single-layer hard mask with vertically stacked photoresist patterns, the invention removes the need for intermediate planarization steps that are typically required when using multiple film stacks, thereby simplifying the process while maintaining fine pattern precision
Solution Approach 2:
The patent segments the patterning process into distinct vertical stages within a single hard mask layer. Instead of using multiple horizontal film stacks, the invention creates vertically stacked photoresist patterns (first and second photoresist layers) that are transferred sequentially into the single hard mask layer, achieving complex cross-pitch patterns without increasing lateral layer complexity
2Manufacturing precision
If multiple layers are stacked to achieve fine patterns, then manufacturing precision is improved, but aspect ratio increases causing variations
Solution Approach 1:
The patent transitions from a lateral multi-layer approach to a vertical stacking approach within a single hard mask layer. By stacking photoresist patterns vertically and transferring them sequentially into the hard mask, the invention achieves fine patterns without creating high aspect ratio structures, as all patterns are formed within the plane of a single hard mask layer rather than through tall vertical stacks
3Manufacturing precision
If multiple film stacks are used to achieve fine patterns, then manufacturing precision is improved, but fabricating time and cost increase
Solution Approach 1:
The patent merges multiple patterning operations into a single hard mask layer. By combining the functions of multiple hard masks into one layer and using vertically stacked photoresist patterns for sequential pattern transfer, the invention reduces the total number of fabrication steps, including eliminating planarization steps, thereby improving fabrication efficiency and reducing costs while maintaining fine pattern precision
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 reduces the aspect ratio, simplifies the process, and lowers costs by eliminating the need for multiple layers and planarization steps, enabling more precise and efficient semiconductor device manufacturing.
Implementation Method 1
the second and third layer have a very good etching selectivity from one another
Implementation Method 2
using Atomic Layer Deposition and photoresist trimming to create double pitch patterns
Data Source
AI summary
The present invention provides a method of cross double pitch patterning for forming a contact printing mask. First, a first, a second and a third layer a successively deposited; a photoresist is deposited on the third layer, and then trimmed into a first pre-pattern, on which an oxide layer is deposited. The oxide layer is etched into spacers forming a first pattern that is then etched into the third layer. A second cross pattern is formed the same way on the third layer. Finally the first and second layers are etched with selectivity both patterns.