Gas Distribution Module for Fluorine Radical Recombination Control
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in precisely controlling the recombination rate of fluorine radicals during plasma etching of silicon germanium (SiGe), leading to potential damage to silicon (Si) due to free fluorine particles.
Innovation Solution
A gas distribution module with an upper electrode, ion blocker, showerhead, and purge gas supply unit is used to control the recombination rate of fluorine radicals by adjusting the flow of purge gases like argon, nitrogen, or helium in the recombination region, along with pressure measurement and control valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fluorine radicals are generated in the plasma generation region for etching silicon germanium, then the etch rate is improved, but silicon damage occurs due to free fluorine remaining after radical generation
Solution Approach 1:
A recombination region is introduced as an intermediary space between the plasma generation region and the substrate. This recombination region allows fluorine radicals to recombine into molecular fluorine before reaching the substrate, preventing silicon damage while maintaining etching capability. The recombination region acts as a buffer zone that mediates between radical generation and substrate processing.
Solution Approach 2:
The processing space is segmented into distinct regions: a plasma generation region for creating fluorine radicals, a recombination region for converting radicals to molecules, and a processing region for substrate etching. This spatial segmentation allows independent control of radical generation and recombination processes, enabling precise control over the etching chemistry.
2Object-affected harmful factors
If the recombination rate of fluorine radicals is increased to prevent silicon damage, then the amount of free fluorine is reduced, but the etch rate decreases
Solution Approach 1:
Different regions of the gas distribution module have different functional qualities: the plasma generation region is optimized for radical creation, the recombination region is optimized for radical-to-molecule conversion, and the processing region is optimized for etching. This local differentiation allows each region to perform its specific function optimally without compromising overall process performance.
Solution Approach 2:
The system dynamically controls the flow rates of process gas and purge gas to adjust the recombination rate in real-time. By varying gas flow conditions, the system can optimize the balance between radical recombination (to prevent damage) and radical availability (for etching), adapting to different processing requirements.
3Manufacturing precision
If a recombination region is introduced to control fluorine radical recombination, then process precision is improved, but the device complexity increases
Solution Approach 1:
The recombination region is integrated with the existing plasma generation and processing regions within a single gas distribution module. The purge gas supply unit is merged into the module structure, combining multiple functions (radical recombination, gas flow control, pressure regulation) into one unified device, thereby managing complexity through functional integration.
Solution Approach 2:
The recombination region operates autonomously using the supplied purge gas to facilitate radical recombination without requiring external intervention. The system self-regulates the recombination process through controlled gas flow and pressure, reducing the need for additional complex control mechanisms.
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 solution effectively adjusts the recombination rate of fluorine radicals, preventing silicon damage and enhancing the etch rate for silicon germanium, thereby improving process precision and efficiency.
Implementation Method 1
an ion blocker disposed under the upper electrode to form a plasma generation region
Implementation Method 2
the fluorine radicals may flow to the recombination region through a through-hole formed in the upper electrode and may be combined with one another in the recombination region to generate fluorine gas
Implementation Method 3
a purge gas supply unit configured to supply a purge gas to the recombination region
Implementation Method 4
the gas distribution module may further include a pressure gauge configured to measure pressure in the recombination region, and the purge gas supply unit may control the flow rate of the purge gas according to the pressure measured by the pressure gauge
Implementation Method 5
Processes using plasma, for example, etching and deposition, are widely used in the semiconductor manufacturing process
Data Source
AI summary
Disclosed are a gas distribution module capable of effectively adjusting the recombination rate of radical components, a substrate processing method, and a substrate processing apparatus. The gas distribution module configured to supply a gas to a processing region in a substrate processing apparatus using plasma includes an upper electrode, an ion blocker disposed under the upper electrode to form a plasma generation region, a showerhead disposed under the ion blocker to form a recombination region, and a purge gas supply unit configured to supply a purge gas to the recombination region.