Halogen-Enhanced Ashable Hard Mask for Higher Etch Selectivity
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Solution Overview
Problem
Current ashable hard masks (AHMs) in semiconductor processing have limitations due to high hydrogen content, leading to increased etch rates and reduced etch selectivity, necessitating improvements in etch resistance and selectivity without compromising deposition rate or film properties.
Innovation Solution
The use of halogen-containing precursors in plasma-enhanced chemical vapor deposition (PECVD) processes to form AHMs, which reduce hydrogen and halogen content, enhancing etch resistance and selectivity by incorporating halogen atoms that act as hydrogen getters and participate in the deposition process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional precursors are used to deposit AHM, then deposition rate is maintained, but etch resistance and selectivity deteriorate due to high hydrogen content
Solution Approach 1:
The patent changes the chemical composition parameters of the precursor by incorporating halogen-containing compounds (such as CF4, C2F6, C2F8) into the deposition process. This parameter change transforms the AHM film composition from hydrogen-rich to halogen-enriched, fundamentally altering the film's etch resistance properties while maintaining deposition rate
Solution Approach 2:
The patent creates a composite AHM film structure by combining carbon-based materials with halogen-containing species. The resulting composite film exhibits synergistic properties where the halogen component provides enhanced etch resistance while the carbon matrix maintains the ashable characteristic, resolving the contradiction between etch resistance and hydrogen content
2Reliability
If AHM thickness is increased to improve selectivity, then etch selectivity improves, but process complexity and deposition time increase
Solution Approach 1:
By changing the precursor composition to include halogen-containing species, the patent achieves higher etch selectivity at comparable or reduced thickness levels. The halogen-enriched film provides enhanced etch resistance per unit thickness, reducing the total deposition time required to achieve the necessary selectivity for HAR processes
3Reliability
If hydrogen content in AHM is reduced to improve etch resistance, then etch selectivity improves, but deposition process complexity increases
Solution Approach 1:
The patent introduces halogen-containing precursors as intermediary substances that facilitate the reduction of hydrogen content in the AHM film. These intermediaries react during deposition to incorporate halogen atoms into the film matrix, effectively displacing hydrogen and enhancing etch resistance through a controlled chemical mechanism rather than direct hydrogen removal
Solution Approach 2:
The patent modifies the deposition process parameters by adjusting precursor ratios, plasma power, and pressure conditions to optimize halogen incorporation. These parameter changes enable precise control over film composition, achieving low hydrogen content and high etch selectivity through systematic process optimization rather than complex multi-step procedures
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 approach results in AHMs with lower hydrogen content, improved etch rates, and higher selectivity, allowing for more efficient HAR semiconductor processes while maintaining comparable deposition rates and film properties.
Implementation Method 1
depositing on the surface an ashable hard mask film (AHM) by a plasma enhanced chemical vapor deposition (PECVD) process
Implementation Method 2
incorporating halogen atoms that act as hydrogen getters and participate in the deposition process
Data Source
AI summary
Provided herein are methods and related apparatuses for forming an ashable hard mask (AHM). In particular instances, use of a halogen-containing precursor can provide an AHM having improved etch resistance.