Dry Plasma Etching Silicon ARC Layer CD Bias Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional plasma etch processes fail to maintain uniform critical dimension (CD) and reduce CD bias offset between nested and isolated structures during pattern transfer in silicon-containing anti-reflective coating (ARC) layers on semiconductor substrates.
Innovation Solution
A method involving a multi-layer mask with a lithographic layer overlying a silicon-containing ARC layer, using a dry plasma etching process with specific gas chemistries like SF6 and CO2 to transfer patterns, reducing CD bias offset by optimizing process recipes and etch conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma etch processes are used to transfer patterns from lithographic layer to silicon-containing ARC layer, then pattern transfer is achieved, but critical dimension (CD) bias offset between nested and isolated structures increases and uniformity is reduced
Solution Approach 1:
The patent applies parameter changes by modifying plasma etch process conditions including gas composition (SF6, CO2, O2 ratios), pressure, power, and temperature to reduce CD bias offset. Specifically, the process uses a two-step etch recipe where the first step uses SF6-based plasma with specific parameters to etch the ARC layer, and the second step uses CO2-based plasma to complete the transfer, achieving uniform CD across nested and isolated structures
Solution Approach 2:
The patent segments the pattern transfer process into multiple distinct etch steps with different gas chemistries and parameters. The first etch step uses SF6 plasma for initial ARC layer removal, followed by a second step using CO2 plasma for precise feature definition. This segmentation allows independent optimization of each step to minimize CD bias and achieve uniform pattern transfer
2Manufacturing precision
If plasma etch process removes material along fine lines and within vias, then pattern transfer from resist layer to underlying layer is achieved, but CD bias difference between initial and final CD increases
Solution Approach 1:
The patent divides the pattern transfer process into multiple sequential etch steps, each with specific gas chemistry and parameters. The first step uses SF6 plasma for ARC layer etching, and the second step uses CO2 plasma for precise feature transfer. This segmentation enables better CD control through optimized parameters for each step while maintaining manufacturability
Solution Approach 2:
The patent employs parameter changes by adjusting gas composition (SF6 to CO2 transition), pressure, power, and temperature between etch steps to control CD bias. The process recipe is specifically optimized to achieve minimal CD difference between initial lithographic pattern and final etched features
3Productivity
If dry plasma etching process is used to transfer feature pattern, then pattern transfer efficiency is improved, but CD bias offset between nested and isolated structures increases
Solution Approach 1:
The patent uses parameter changes in the dry plasma etch process, specifically transitioning from SF6-based plasma to CO2-based plasma between steps, and optimizing pressure, power, and gas flow rates to maintain high transfer efficiency while reducing CD bias offset between nested and isolated structures
Solution Approach 2:
The patent segments the dry plasma etching into multiple steps with different gas chemistries. The first step uses SF6 plasma for efficient ARC layer removal, and the second step uses CO2 plasma for precise feature definition, maintaining productivity while achieving uniform CD bias across different structure types
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
The method effectively reduces CD bias offset between nested and isolated structures, maintaining uniformity in pattern transfer across the substrate, improving the precision of feature etching in semiconductor fabrication.
Implementation Method 1
forming plasma from the process gas in the plasma processing system according to the process recipe
Data Source
AI summary
A method of dry developing a multi-layer mask having a silicon-containing anti-reflective coating (ARC) layer on a substrate is described. The method comprises forming the multi-layer mask on the substrate, wherein the multi-layer mask comprises a lithographic layer overlying the silicon-containing ARC layer. A feature pattern is then formed in the lithographic layer using a lithographic process. Thereafter, the feature pattern is transferred from the lithographic layer to the silicon-containing ARC layer using a dry plasma etching process, wherein the offset in the critical dimension (CD) bias is reduced between nested structures and isolated structures.