Ground Electrode for Plasma Generation Box in Substrate Processing
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Solution Overview
Problem
In substrate processing for semiconductor wafers, high-frequency plasma generation leads to a strong electric field between the plasma generating electrode and the wafer, causing plasma damage and particle generation, especially at the wafer edges.
Innovation Solution
A substrate processing apparatus is designed with a plasma generation box partitioned by a plasma partition wall and an inductively coupled electrode, along with a ground electrode positioned outside the plasma generation box to reduce the electric field strength near the wafer, using a configuration that includes a winding inductively coupled electrode and a ground electrode to minimize ion acceleration and particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high-frequency plasma generation is used to enable low-temperature substrate processing, then plasma processing capability is improved, but electric field strength between electrode and wafer increases causing plasma damage and particle generation
Solution Approach 1:
A ground electrode is introduced as an intermediary component between the plasma generating electrode and the wafer. This ground electrode serves as a mediator that captures and dissipates excess electric field energy, preventing direct interaction between the high-voltage plasma electrode and the wafer, thereby reducing plasma damage to the wafer edge while maintaining low-temperature processing capability
Solution Approach 2:
The harmful electric field effect is extracted and isolated from the wafer processing zone by introducing the ground electrode. The ground electrode specifically targets and removes the excessive electric field energy in the vicinity of the wafer, separating the plasma generation function from the harmful electric field effect
2Productivity
If high voltage is applied to plasma generating electrode for high-frequency plasma generation, then plasma generation efficiency is improved, but electric field strength increases causing ion acceleration and particle generation
Solution Approach 1:
The ground electrode acts as an intermediary that intercepts accelerated ions before they reach the wafer. By providing an intermediate grounding point, it dissipates ion kinetic energy and prevents ion bombardment damage, thereby reducing particle generation while maintaining high plasma generation efficiency through high voltage application
Solution Approach 2:
The ground electrode converts the harmful high-voltage electric field effect into a beneficial function. By strategically placing the ground electrode, the excessive electric field energy that would cause particle generation is redirected to create a controlled grounding path, transforming the harmful high voltage into a protective mechanism that shields the wafer from ion damage
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 apparatus effectively suppresses plasma generation near the wafer, reducing particle formation and maintaining high plasma density for efficient processing while protecting the wafer edges.
Implementation Method 1
an inductively coupled electrode located at an outer sidewall of the plasma generation box along its length direction; a high frequency power supply connected to the inductively coupled electrode through a feed line
Implementation Method 2
a ground electrode located outside the plasma generation box and between the processing vessel and the inductively coupled electrode, arranged in the vicinity of the outer sidewall of the plasma generation box or at least partially in contact with the outer sidewall, and extended toward an outside of the plasma generation box
Data Source
AI summary
A substrate processing apparatus includes: a processing vessel configured to be vacuumed; a holding unit configured to hold a plurality of substrates and to be inserted into or separated from the processing vessel; a gas supply unit configured to supply gas into the processing vessel; a plasma generation box partitioned and formed by a plasma partition wall; an inductively coupled electrode located at an outer sidewall of the plasma generation box along its length direction; a high frequency power supply connected to the inductively coupled electrode through a feed line; and a ground electrode located outside the plasma generation box and between the processing vessel and the inductively coupled electrode and arranged in the vicinity of the outer sidewall of the plasma generation box or at least partially in contact with the outer sidewall.