Ion Implantation Beam Interruption for Plasma Ignition
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Solution Overview
Problem
The ion implantation apparatus faces issues with overcurrent generation due to charged particles produced when the ion beam collides with source gas in the beam line, degrading the vacuum and potentially causing power supply overload during plasma ignition.
Innovation Solution
Incorporating an interruption member in the beam line to temporarily halt the ion beam during plasma shower device ignition, preventing charged particle generation and maintaining a stable vacuum, while allowing plasma generation to proceed safely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the plasma generation device introduces a large amount of source gas during the plasma ignition period, then the plasma generation efficiency is improved, but the vacuum degree of the implantation processing chamber is degraded and charged particles are generated in the beam line
Solution Approach 1:
The beam line is segmented into multiple sections with vacuum barriers. The plasma generation chamber is isolated from the beam line vacuum system during ignition, allowing large amounts of source gas to be introduced without degrading the beam line vacuum. The beam line is divided into upstream and downstream sections relative to the plasma chamber, with each section maintaining independent vacuum control.
Solution Approach 2:
A vacuum barrier or isolation mechanism acts as an intermediary between the plasma generation chamber and the beam line. This intermediary allows the plasma chamber to operate with high source gas flow while protecting the beam line vacuum from degradation. The intermediary enables independent operation of the two systems during the ignition phase.
2Productivity
If the ion beam is continuously transmitted through the beam line, then the ion implantation process efficiency is improved, but the power supply may experience overcurrent due to load current generation from charged particles
Solution Approach 1:
The plasma generation device is activated in advance before ion implantation begins. This preliminary plasma generation creates a protective plasma environment that reduces charged particle generation during subsequent ion beam transmission. The plasma is established as a preliminary condition to prevent overcurrent issues during the main implantation process.
Solution Approach 2:
The ion beam transmission is controlled in periodic cycles, alternating between beam transmission and interruption periods. During plasma ignition, the beam is interrupted to prevent overcurrent. Once plasma is established, the beam is restored. This periodic control prevents power supply overcurrent while maintaining overall process efficiency.
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 suppresses load current generation, protecting the power supply and reducing start-up time for ion implantation processes by interrupting the ion beam during plasma ignition, thus enhancing operational efficiency and productivity.
Implementation Method 1
a discharging mechanism that generates plasma by causing a discharge in the introduced source gas is provided inside the implantation processing chamber
Implementation Method 2
an ion source, a drawn electrode, a mass-spectrometry magnet, a mass-spectrometry slit, an acceleration/deceleration device, a wafer processing chamber, and the like are disposed along the beam line and ions are implanted into a wafer as a semiconductor substrate. These devices control the ion beam by using an electric field formed between the electrodes to which a voltage is applied
Implementation Method 3
a control unit that causes the interruption member to interrupt the ion beam during an ignition start period of the plasma shower device
Data Source
AI summary
In an ion implantation apparatus, an interruption member interrupts an ion beam B in the middle of a beam line. A plasma shower device is provided at the downstream side of the interruption member in the beam line. A control unit causes the interruption member to interrupt the ion beam B during an ignition start period of the plasma shower device. The interruption member may be provided at the upstream side of at least one high-voltage electric field type electrode in the beam line. A gas supply unit may supply a source gas to the plasma shower device. The control unit may start the supply of the source gas from the gas supply unit after the ion beam B is interrupted by the interruption member.