Grounded Ion Filter Chamber for Uniform ALE and Selective Etching
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Solution Overview
Problem
Conventional etching technologies face challenges in achieving uniformity and repeatability across 300 mm wafers, particularly for high aspect ratio structures, due to the difficulty in balancing ion and neutral fluxes, leading to non-uniform layer removal and undesirable etching profiles, especially in advanced semiconductor manufacturing.
Innovation Solution
A novel chamber design with an upper and lower section separated by a grounded ion filter (GIF) allows neutral species to pass while blocking ions, enabling an inductively coupled plasma reactor for surface modification and a capacitively coupled plasma reactor for sputtering, with a tailored waveform to control ion energy distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional RIE process is used with both ion and neutral fluxes to enhance etching rate, then etching speed is improved, but uniformity and repeatability across 300 mm wafers deteriorates
Solution Approach 1:
The plasma process is segmented into two distinct phases: a high-density plasma phase for surface modification and a low-density plasma phase for material removal. This segmentation allows optimization of each phase independently, achieving both high etching rate and uniformity across 300mm wafers
Solution Approach 2:
The patent implements periodic alternation between high-density and low-density plasma phases. The high-density phase modifies the surface to enhance reactivity, followed by a low-density phase that removes material uniformly. This periodic action resolves the contradiction by decoupling the requirements for high etching rate and uniformity into separate temporal phases
2Shape
If ion flux is increased to improve etching anisotropy for high aspect ratio structures, then directional etching is improved, but non-uniform layer removal and undesirable etching profiles worsen
Solution Approach 1:
The patent dynamically adjusts plasma density between two states: high-density for surface modification and low-density for anisotropic etching. This dynamic control allows the system to achieve directional etching for high aspect ratio structures while maintaining uniform layer removal, as each phase is optimized for its specific function
Solution Approach 2:
The patent changes plasma density parameters between phases. During the low-density phase, ion flux is controlled to provide sufficient anisotropy for high aspect ratio structures, while the high-density phase compensates by enhancing surface reactivity. This parameter switching resolves the contradiction between anisotropy and uniformity
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 design enhances the ideality of atomic layer etching (ALE) and radical-based highly selective etching (HSE) processes, improving uniformity, precision, and consistency, especially for high aspect ratio structures, reducing cycle time and costs.
Implementation Method 1
The chamber is divided into an upper chamber and a lower chamber by a grounded ion filter that allows neutral species, such as radicals, to pass between the chambers while blocking ions
Implementation Method 2
enabling an inductively coupled plasma reactor for surface modification
Implementation Method 3
a capacitively coupled plasma reactor for sputtering
Data Source
AI summary
Disclosed herein is a system and method for integrating atomic layer etching (ALE) and radical-based highly selective etching (HSE) within a single process chamber. The innovative design, featuring a grounded ion filter (GIF), enables the precise control of ions and neutrals during etching. The system improves process efficiency, enhances selectivity, and reduces cycle times, making it ideal for manufacturing high-performance semiconductor devices with complex, high aspect ratio structures.