Dual Plenum Showerhead for Selective Photoresist Etching
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Solution Overview
Problem
Existing substrate processing systems face challenges in selectively removing photoresist layers without causing damage to underlying materials due to ion and photon flux exposure, leading to substrate loss and reduced removal rates.
Innovation Solution
A substrate processing system with a dual chamber configuration uses metastable species generated in an upper chamber to transfer energy to reactive gas species, filtering ions and UV light, and delivering these species to a lower chamber for selective etching, achieving high selectivity and reduced substrate loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct plasma (CCP or ICP) is used to strip photoresist, then removal rate is high and stripping is performed without vacuum break, but ions and VUV photons generated by the plasma damage underlying layers and cause substrate loss
Solution Approach 1:
The plasma source is divided into two separate chambers: an upper chamber for plasma generation and a lower chamber for substrate processing. This spatial segmentation allows the plasma to be generated away from the substrate, eliminating direct exposure to harmful ions and photons while maintaining high removal rates through metastable species transfer.
Solution Approach 2:
The harmful components (ions and VUV photons) are extracted or filtered out from the plasma before it reaches the substrate. The gas distribution device with its specific hole configuration and the light blocking structure remove these harmful factors while allowing metastable species to pass through and continue the photoresist stripping process.
2Object-affected harmful factors
If downstream plasma sources (ICP, ECR, or microwave) with showerhead are used to minimize ion and photon exposure, then substrate loss is reduced, but removal rate is lower due to surface recombination on dome/tube surfaces and chamber walls
Solution Approach 1:
Metastable species serve as intermediaries to transfer the photoresist stripping function from the plasma source to the substrate. These long-lived species can travel through the gas distribution device without recombining on surfaces, delivering the etching capability to the photoresist while avoiding surface recombination losses that plague conventional downstream plasma systems.
Solution Approach 2:
The system changes the physical parameters of plasma species utilization by focusing on metastable atoms rather than reactive radicals. This parameter change allows the plasma to maintain its photoresist stripping capability while eliminating the harmful effects of ions and photons, and avoiding surface recombination losses.
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 system achieves a photoresist etch selectivity ratio greater than 50:1 relative to other materials, with reduced substrate damage and higher removal rates compared to traditional methods.
Implementation Method 1
A plasma generating system generates plasma including ions and metastable species in the first chamber
Implementation Method 2
radio frequency (RF) plasma may be used to activate chemical reactions
Implementation Method 3
A gas distribution device is arranged between the first chamber and the second chamber to remove the ions from the plasma
Implementation Method 4
block ultraviolet (UV) light generated by the plasma
Implementation Method 5
The metastable species transfer energy to the reactive gas species to selectively etch one exposed material of the substrate
Implementation Method 6
selectively removing film from a substrate with high selectivity
Data Source
AI summary
Several designs of a gas distribution device for a substrate processing system are provided. The gas distribution device includes a dual plenum showerhead. Additionally, designs for a light blocking structure used with the showerheads are also provided.