Semiconductor Stripe Structures Polymer Mask Etching
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Solution Overview
Problem
The challenge in semiconductor manufacturing lies in forming stripe structures with precise corner angles and critical dimensions, as existing dry etching processes lead to over-etching and bridging issues due to the shrinking dimensions, causing position errors and short circuits in poly silicon gates and interconnect lines.
Innovation Solution
A method involving a hard mask pattern and a polymer layer formed on the photoresist pattern to control the width of stripe openings, allowing for precise etching of stripe structures using a double-patterning and double-etching technique, which reduces the risk of bridging and improves morphology control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dry etching process is used to form stripe structures, then manufacturing efficiency is improved, but corner angles become overly etched and turn into arcs
Solution Approach 1:
The patent applies segmentation by dividing the single etching process into multiple etching steps (first etching process and second etching process). The first etching process forms initial stripe structures, and the second etching process refines the corner angles. This segmentation allows each etching step to be optimized independently, preventing over-etching while maintaining manufacturing efficiency.
Solution Approach 2:
The patent uses preliminary action by forming a protective layer on the stripe structures before the second etching process. This protective layer is applied in advance to prevent over-etching of the corner angles during the refinement step, ensuring precise corner angle formation while maintaining overall manufacturing efficiency.
2Manufacturing precision
If double-lithography and double-etching method is used to overcome over-etching, then corner angle precision is improved, but process complexity increases
Solution Approach 1:
The patent merges the formation of stripe structures and the refinement of corner angles into a unified double-etching process that shares common process parameters and equipment. By combining these operations under a single process flow with integrated control, the patent reduces the overall process complexity while maintaining high corner angle precision.
Solution Approach 2:
The patent applies parameter changes by systematically varying etching parameters (such as etch rate, plasma power, gas flow) between the first and second etching processes. This allows optimization of each step for its specific purpose (initial formation vs. corner refinement) while maintaining overall process simplicity through consistent parameter management.
3Manufacturing precision
If photolithography process is used to form stripe patterns, then pattern definition is improved, but bridging occurs between adjacent stripe structures
Solution Approach 1:
The patent applies preliminary anti-action by forming a protective layer on the stripe structures before the second etching process. This protective layer acts in advance to prevent material deposition or bridging between adjacent stripes during the etching and cleaning processes, thereby maintaining pattern definition while preventing bridging.
Solution Approach 2:
The protective layer serves as an intermediary between the photolithography-formed patterns and the subsequent etching processes. It mediates the interaction by protecting the stripe structures from over-etching and preventing bridging, while allowing the photolithography pattern definition to be preserved throughout the manufacturing process.
4Productivity
If stripe structures are made thinner to meet technology requirements, then device density is improved, but over-etching and bridging issues worsen
Solution Approach 1:
The patent segments the etching process into two distinct steps, allowing the first step to form thin stripe structures with appropriate margins and the second step to precisely define the final dimensions. This segmentation enables the formation of thinner structures with better control over corner angles and reduced risk of over-etching.
Solution Approach 2:
The protective layer is applied preliminarily before the second etching process to protect the thin stripe structures from over-etching. This preliminary protection allows the stripe structures to be made thinner while maintaining their integrity and preventing bridging during the refinement step.
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 enables the formation of stripe structures with improved morphology and reduced bridging, ensuring accurate placement of poly silicon gates and interconnect lines, thereby preventing short circuits and enhancing the reliability of semiconductor devices.
Implementation Method 1
forming a polymer layer on a top surface and side surfaces of the photoresist pattern to reduce a width of the stripe opening
Implementation Method 2
forming hard mask patterns having a second stripe by etching the hard mask pattern having the first stripe using the photoresist pattern having the polymer layer as an etching mask
Data Source
AI summary
A method is provided for fabricating stripe structures. The method includes providing a substrate; and forming a to-be-etched layer on the substrate. The method also includes forming a hard mask pattern having a first stripe on the to-be-etched layer; and forming a photoresist pattern having a stripe opening on the to-be-etched layer and the hard mask pattern having the first stripe. Further, the method includes forming a polymer layer on a top surface and side surfaces of the photoresist pattern to reduce a width of the stripe opening; forming hard mask patterns having a second stripe by etching the hard mask pattern having the first stripe using the photoresist pattern having the polymer layer as an etching mask; and forming the stripe structures by etching the to-be-etching layer using the hard mask pattern having the second stripe as an etching mask until the substrate is exposed.