Ion Implantation Speed Control for Wafer Non-Uniformity Correction
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Solution Overview
Problem
In semiconductor manufacturing, achieving uniform ion implantation across a wafer surface is challenging, especially with the miniaturization of semiconductor chips, leading to non-uniformity and varying electrical characteristics, which prevents the creation of chips with consistent performance. Existing methods struggle to generate intentional non-uniform two-dimensional ion implantation distributions without using step rotation, particularly in dealing with concentric circle, eccentric, and elliptical shapes that occur in plasma and annealing processes.
Innovation Solution
The method involves controlling the speed of ion beam scanning and mechanical wafer scanning independently to create intentional non-uniform two-dimensional ion implantation distributions of concentric circle, eccentric, and elliptical shapes on the wafer surface by using speed correction amounts that are proportional to the square of the distance from the wafer center or an arbitrary point, allowing for flexible correction and pattern formation without step rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If uniform ion implantation is performed across the wafer surface, then manufacturing precision is improved, but device complexity increases due to the need for step rotation or complex scanning patterns
Solution Approach 1:
The invention extracts the step rotation function from the ion implantation apparatus by performing ion implantation in a single direction without rotating the wafer. The non-uniformity correction is achieved through independent speed control of the ion beam and wafer, eliminating the need for complex step rotation mechanisms while maintaining implantation uniformity.
Solution Approach 2:
The invention changes the control parameters from fixed scanning speeds to variable speeds with correction amounts proportional to the square of the distance from the wafer center. This parameter change allows uniform ion implantation to be achieved through speed modulation rather than mechanical rotation, simplifying the device structure.
2Manufacturing precision
If speed correction amounts proportional to the square of the distance from the wafer center are applied, then ion implantation uniformity is improved, but control system complexity increases
Solution Approach 1:
The invention applies speed correction amounts that are proportional to the square of the distance from the wafer center, transforming the control parameters from constant speeds to position-dependent variable speeds. This mathematical relationship simplifies the control logic while achieving uniform ion implantation distribution across the wafer surface.
Solution Approach 2:
The invention replaces complex mechanical adjustments with electronic speed control. By using control functions that define speed correction amounts based on position, the system achieves precise ion implantation uniformity through software-based parameter adjustment rather than mechanical modification.
3Adaptability or versatility
If independent speed control of ion beam and wafer is implemented, then adaptability for correcting various non-uniformity patterns is improved, but control system complexity increases
Solution Approach 1:
The invention implements independent speed control for both the ion beam and wafer, allowing separate adjustment of their respective scanning speeds. This dual parameter control enables flexible correction of various non-uniformity patterns (concentric circle, eccentric, elliptical shapes) by modifying speed profiles without changing the physical configuration of the system.
Solution Approach 2:
The independent speed control system serves multiple functions: it can correct concentric circle non-uniformity, eccentric non-uniformity, and elliptical non-uniformity patterns using the same control mechanism. This universal approach eliminates the need for different correction mechanisms for different patterns, reducing overall system complexity.
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 approach enables the creation of continuous and smooth non-uniform ion implantation distributions that match the shapes of surface non-uniformities, correcting wafer surface irregularities and ensuring consistent chip performance without the limitations of step rotation, thus addressing the challenge of achieving uniformity in semiconductor manufacturing processes.
Implementation Method 1
a process for introducing ions into a semiconductor wafer is performed
Implementation Method 2
forming an accelerated ion beam, and a function of irradiating the entire surface of the semiconductor wafer with the ion beam, through beam scanning
Implementation Method 3
mechanically scanning a wafer in a direction perpendicular to the ion beam scanning direction
Data Source
AI summary
An ion implantation method includes reciprocally scanning an ion beam, mechanically scanning a wafer in a direction perpendicular to the ion beam scanning direction, implanting ions into the wafer, and generating an ion implantation amount distribution in a wafer surface of an isotropic concentric circle shape for correcting non-uniformity in the wafer surface in other semiconductor manufacturing processes, by controlling a beam scanning speed in the ion beam scanning direction and a wafer scanning speed in the mechanical scanning direction at the same time and independently using the respective control functions defining speed correction amounts.