Ion Implanter Controller for Non-Uniform Dose Patterns
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Solution Overview
Problem
Conventional ion implanters lack the ability to directly create a desired two-dimensional non-uniform dose pattern efficiently, often requiring multiple passes and rotations, which adversely affects throughput and limits the dose pattern to symmetrical designs.
Innovation Solution
An ion implanter system that includes a controller to receive an input signal for a desired two-dimensional non-uniform dose pattern, driving the workpiece relative to an ion beam, and controlling at least one parameter, such as scan velocity or beam current density, to directly create the pattern in one pass, allowing for arbitrary non-uniform patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple passes and rotations are used to create non-uniform dose patterns, then the desired dose pattern can be approximated, but throughput performance deteriorates and the pattern is limited to symmetrical designs
Solution Approach 1:
The patent applies dynamics by making the beam scan velocity variable rather than constant. The controller dynamically adjusts the scan velocity according to a programmed velocity profile that corresponds to the desired non-uniform dose pattern. This allows arbitrary two-dimensional dose distributions to be created in a single pass, eliminating the need for multiple passes and rotations while maintaining pattern accuracy and improving throughput.
2Adaptability or versatility
If multiple passes of different uniform doses are used in different regions, then a non-uniform dose pattern can be created, but the actual pattern does not accurately match the desired pattern and additional time is required
Solution Approach 1:
The patent changes the scan velocity parameter dynamically during the beam scanning process. By programming the velocity as a function of position according to the desired dose distribution, the system can directly create arbitrary non-uniform dose patterns with high accuracy. This eliminates the approximation errors inherent in using multiple passes of uniform doses and achieves both flexibility and precision simultaneously.
3Manufacturing precision
If scan velocity is controlled in one scanned direction only, then a non-uniform dose pattern can be created, but the wafer must be rotated and multiple passes are required, affecting throughput
Solution Approach 1:
The patent extends the velocity control from one dimension to two dimensions by implementing independent velocity control in both scanned directions (X and Y axes). The controller programs the beam scan velocity in both directions simultaneously based on the desired two-dimensional dose pattern. This allows arbitrary non-uniform dose distributions across the entire wafer surface to be created in a single pass without rotation, achieving both precise control and high throughput.
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
Enables the direct creation of two-dimensional non-uniform dose patterns in a single pass, improving throughput and allowing for arbitrary pattern designs beyond symmetrical limitations, while maintaining accuracy and efficiency.
Implementation Method 1
Ion implantation is a standard technique for introducing conductivity—altering impurities into a workpiece such as a semiconductor wafer. The energetic ions in the beam penetrate into the bulk of the semiconductor material and are embedded into the crystalline lattice of the semiconductor material to form a region of desired conductivity.
Data Source
AI summary
A method includes receiving an input signal representative of a desired two-dimensional non-uniform dose pattern for a front surface of a workpiece, driving the workpiece relative to an ion beam to distribute the ion beam across the front surface of the workpiece, and controlling at least one parameter of an ion implanter when the ion beam is incident on the front surface of the workpiece to directly create the desired two-dimensional non-uniform dose pattern in one pass of the front surface of workpiece relative to the ion beam. The beam may be a scanned beam or a ribbon beam. An ion implanter is also provided.