Ion Implantation Apparatus Dynamic Scan Frequency Control
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Solution Overview
Problem
Existing ion implantation technologies face challenges in achieving a uniform two-dimensional ion implantation distribution on semiconductor wafers due to constraints in beam scan frequency, leading to uneven implantation and wafer damage, especially when attempting to realize non-uniform dose distributions with high ratios of in-plane dose amounts.
Innovation Solution
An ion implantation apparatus and method that utilize a beam scanner and mechanical scanner controlled by a frequency-adjusting unit to generate a scan waveform, allowing for variable scan speeds across different regions of the wafer, ensuring precise control of ion beam distribution and reducing side effects from frequency changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the beam scan frequency is increased to achieve uniform ion implantation distribution, then the uniformity of ion implantation is improved, but the beam scanner's operational limits are exceeded and wafer damage occurs
Solution Approach 1:
The patent applies dynamics by making the beam scan frequency variable rather than fixed. The control device dynamically adjusts the beam scan frequency according to the position on the wafer surface, allowing higher frequencies in regions requiring uniform implantation and lower frequencies in other regions, thus avoiding wafer damage while maintaining implantation uniformity where needed
Solution Approach 2:
The patent changes the parameter of beam scan frequency from a constant value to a position-dependent variable. The control device modifies the scan frequency parameter based on the target dose distribution requirements and wafer position, enabling precise control of ion implantation characteristics without exceeding equipment limits or causing wafer damage
2Object-affected harmful factors
If the beam scan frequency is decreased to avoid wafer damage, then wafer damage is reduced, but non-uniform ion implantation distribution occurs
Solution Approach 1:
The patent applies local quality by implementing different beam scan frequencies for different regions of the wafer. The control device determines position-dependent scan frequencies that match the target dose distribution requirements of each local region, ensuring uniform implantation where high frequency is needed while using lower frequencies in other regions to prevent wafer damage
Solution Approach 2:
The patent changes the beam scan frequency parameter dynamically based on wafer position and target dose requirements. The control device calculates and applies position-specific frequency values, allowing the system to optimize between avoiding wafer damage and achieving uniform ion implantation distribution in critical regions
3Manufacturing precision
If the scan speeds are controlled to be decreased in high dose regions to achieve desired dose distribution, then the target dose amount distribution is improved, but the overall implantation productivity decreases
Solution Approach 1:
The patent applies dynamics by implementing time-varying and position-dependent scan speeds. The control device dynamically adjusts the beam scan speed according to the target dose distribution requirements for each region, allowing slower speeds in high-dose regions to achieve precise dose control while maintaining higher speeds in other regions to preserve overall implantation productivity
Solution Approach 2:
The patent uses periodic reciprocating beam scans with position-dependent frequency control. The control device modulates the scan waveform frequency to create periodic scanning patterns that spend appropriate time in each region according to the target dose distribution, achieving precise dose control without proportionally reducing overall throughput
Data Source
AI summary
An ion implantation apparatus includes a beam scanner that provides a reciprocating beam scan in a beam scan direction in accordance with a scan waveform, a mechanical scanner that causes a wafer to reciprocate in a mechanical scan direction, and a control device that controls the beam scanner and the mechanical scanner to realize a target two-dimensional dose amount distribution on a surface of the wafer. The control device includes a scan frequency adjusting unit that determines a frequency of the scan waveform in accordance with the target two-dimensional dose amount distribution, and a beam scanner driving unit that drives the beam scanner by using the scan waveform having the frequency determined by the scan frequency adjusting unit.