High-Tilt Ion Exposure With Tilt-Scan Angle Matching
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving high-tilt ion processes with improved within-wafer uniformity while minimizing the size of the process chamber, as existing methods often result in non-uniform ion implantation and etching due to the difference between tilt and scan angles.
Innovation Solution
An ion implanter with a wafer handling unit that tilts and moves the wafer to maintain a difference between the tilt angle and scan angle less than a predetermined value, typically around 50°, allowing for high-tilt ion implantations and etching with enhanced uniformity without requiring modifications to existing process chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-tilt ion processes are performed with large difference between tilt angle and scan angle, then ion implantation and etching can be achieved, but within-wafer uniformity deteriorates
Solution Approach 1:
The patent applies dynamics by making the wafer stage movable and tiltable during the ion exposure process. The wafer stage is dynamically adjusted to maintain an optimal relationship between tilt angle and scan angle, specifically keeping their difference below a predetermined threshold. This dynamic adjustment ensures uniform ion exposure across the wafer surface while accommodating high-tilt process requirements, thereby improving within-wafer uniformity without requiring chamber modifications.
2Ease of manufacture
If existing process chambers are used without modification, then ease of manufacture is improved, but ability to perform high-tilt ion processes with good uniformity deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the operational parameters of existing process chambers rather than their physical structure. Specifically, it changes the relationship between tilt angle and scan angle parameters, maintaining their difference below a predetermined value to achieve uniform ion exposure. This parameter optimization allows existing chambers to perform high-tilt ion processes with improved uniformity without requiring hardware modifications, thus maintaining ease of manufacture while improving manufacturing precision.
3Manufacturing precision
If tilt angle and scan angle difference is not controlled, then process flexibility is improved, but ion exposure uniformity deteriorates
Solution Approach 1:
The patent applies feedback by implementing control mechanisms that monitor and adjust the relationship between tilt angle and scan angle during ion exposure processes. The system maintains the difference between these angles below a predetermined threshold through active control, ensuring uniform ion exposure. This feedback-based approach allows the system to adapt to different process conditions while maintaining uniformity, thus preserving process flexibility through programmable control rather than physical constraints.
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 improved within-wafer uniformity during high-tilt ion processes, reducing device defects and enhancing performance by maintaining the scan angle within the predetermined value of the tilt angle, thus allowing for efficient use of existing process chambers.
Implementation Method 1
exposing the wafer to an ion beam
Implementation Method 2
exposing the wafer to an ion beam
Data Source
AI summary
A method of exposing a wafer to a high-tilt angle ion beam and an apparatus for performing the same are disclosed. In an embodiment, a method includes forming a patterned mask layer over a wafer, the patterned mask layer including a patterned mask feature; exposing the wafer to an ion beam, a surface of the wafer being tilted at a tilt angle with respect to the ion beam; and moving the wafer along a scan line with respect to the ion beam, a scan angle being defined between the scan line and an axis perpendicular to an axis of the ion beam, a difference between the tilt angle and the scan angle being less than 50°.