Dual-Direction Chemical Delivery for ALD Uniformity
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Solution Overview
Problem
Multi-channel direct pump-purge systems face challenges in achieving uniformity of chemical deposition due to memory effects from channel length and varying flow characteristics of different chemicals, leading to non-uniform precursor distribution and deposition profiles.
Innovation Solution
A dual-directional chemical delivery system is implemented, allowing for chemical and purge flow to be alternated from both directions within the same hardware setup, compensating for concentration gradients and enhancing deposition uniformity by modulating chemical concentration distribution without complex re-design of hardware components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-channel direct pump-purge systems are used, then productivity and defect reduction are improved, but deposition uniformity deteriorates due to memory effects and concentration gradients
Solution Approach 1:
The patent introduces a second delivery channel that operates in the opposite direction to the first channel. While the first channel delivers precursor from one end, the second channel delivers precursor from the opposite end, creating bidirectional flow that compensates for concentration gradients and memory effects in each individual channel.
Solution Approach 2:
The patent creates different flow conditions in different parts of the system by having two channels with opposite flow directions. Each channel experiences different concentration gradients and residence times, allowing local optimization of precursor distribution across the substrate surface.
2Quantity of substance
If long channel length is used in multi-channel systems, then chemical delivery capability is improved, but memory effects increase leading to non-uniform deposition
Solution Approach 1:
By introducing a second channel with opposite flow direction, the patent counteracts the memory effects and concentration gradients that accumulate in long channels. The bidirectional approach ensures that no single channel experiences excessive residence time or concentration buildup.
3Adaptability or versatility
If different chemicals are used in the same hardware apparatus, then versatility is improved, but flow characteristics vary causing non-uniform precursor distribution
Solution Approach 1:
The patent allows different chemicals to be delivered through different channels with optimized flow characteristics for each chemical type. The bidirectional channel design enables local optimization of flow conditions to accommodate varying viscosity, vapor pressure, and reactivity of different precursors.
Data Source
AI summary
Provided are gas distribution apparatus with a delivery channel having an inlet end, an outlet end and a plurality of apertures spaced along the length. The inlet end is connectable to an inlet gas source and the outlet end is connectible with a vacuum source. Also provided are gas distribution apparatus with spiral delivery channels, intertwined spiral delivery channels, splitting delivery channels, merging delivery channels and shaped delivery channels in which an inlet end and outlet end are configured for rapid exchange of gas within the delivery channels.