High-Pressure Cobalt Etching Using H2 and NO-Hfac Gases
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Solution Overview
Problem
Current etching methods for forming fine wiring in semiconductor devices, such as those using Co films, face inefficiencies in etching rate and gas consumption, particularly due to low internal pressures in processing containers, leading to prolonged process times and increased costs.
Innovation Solution
An etching method involving a processing container with a pressure set higher than 2.40×104 Pa, using a combination of hydrogen (H2) gas for reduction and nitric oxide (NO) and hexafluoroacetylacetone (Hfac) gas to oxidize and etch Co films, optimizing the internal pressure to enhance etching rates and reduce gas usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If low internal pressure is used in the processing container, then gas consumption is reduced, but etching rate decreases and process time increases
Solution Approach 1:
The patent changes the pressure parameter from conventional low pressure to high pressure (higher than 2.40×10^4 Pa). This parameter change fundamentally alters the etching mechanism, enabling rapid etching at high pressure while reducing gas consumption compared to conventional low-pressure methods. The high pressure increases gas density and reaction rate, resolving the contradiction between gas consumption and etching rate.
2Loss of energy
If low internal pressure is used in the processing container, then operational costs are reduced, but process time increases
Solution Approach 1:
By changing the pressure parameter to high pressure (higher than 2.40×10^4 Pa), the patent achieves both reduced operational costs and shortened process time. The high pressure enables more efficient gas utilization and faster etching reactions, simultaneously addressing both cost and time concerns.
3Adaptability or versatility
If conventional etching methods are used, then existing process compatibility is maintained, but etching efficiency is low
Solution Approach 1:
The patent applies parameter changes by operating at high pressure (higher than 2.40×10^4 Pa) while using standard etching gases (Cl2, CF4, SF6). This approach maintains compatibility with existing gas supply systems and process equipment while dramatically improving etching efficiency through the pressure-driven enhancement of reaction rates and gas density.
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 significantly shortens etching time, reduces the amount of Hfac and NO gases required, and maintains surface quality without deteriorating roughness, thereby improving throughput and reducing operational costs.
Implementation Method 1
oxidizing and etching the metallic film by setting an internal pressure of the processing container to a pressure higher than 2.40×104 Pa and supplying an oxidizing gas for oxidizing the metallic film
Implementation Method 2
supplying an etching gas comprising β-diketone into the processing container
Data Source
AI summary
There is provided an etching method, including: loading a substrate having a metallic film formed on the substrate into a processing container; and subsequently, oxidizing and etching the metallic film by setting an internal pressure of the processing container to a pressure higher than 2.40×104 Pa and supplying an oxidizing gas for oxidizing the metallic film and an etching gas comprising β-diketone into the processing container.