Optical Wafer Stage Alignment for Uniform Ion Exposure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor manufacturing faces challenges in achieving uniformity and reducing defects due to misalignments between the wafer and the wafer holder during ion exposure processes, leading to variations in device performance and increased defects.
Innovation Solution
An apparatus and method for detecting and correcting x-direction, y-direction, and rotational misalignments of a wafer on a wafer holder using light emitter/detector pairs and cameras, which shifts the wafer stage to align the wafer properly before the ion exposure process, ensuring perpendicularity and optimal tilt angles for uniform ion exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wafer positioning is performed manually or with simple mechanical alignment, then the device complexity is low, but the manufacturing precision deteriorates due to misalignments between wafer and wafer holder
Solution Approach 1:
The patent replaces manual mechanical alignment operations with an automated optical detection system. Light emitter/detector pairs and cameras detect wafer position and orientation, automatically determining misalignments in x-direction, y-direction, and rotation without requiring manual mechanical adjustment, thereby improving precision while managing complexity through automation.
Solution Approach 2:
The system enables self-alignment by having the wafer stage automatically shift its own position based on detection data. The apparatus detects the misalignment and the same wafer stage performs the correction without external intervention, making the system self-correcting and reducing the need for complex external alignment mechanisms.
2Manufacturing precision
If multiple detection systems are added to detect x-direction, y-direction, and rotational misalignments, then the manufacturing precision improves, but the device complexity increases
Solution Approach 1:
The wafer stage is designed to perform multiple functions: it positions the wafer in x and y directions, rotates the wafer for rotational alignment, and tilts the wafer holder. This multi-functional design consolidates what could be separate complex systems into a single integrated apparatus, improving alignment accuracy across all three parameters while managing overall system complexity.
Solution Approach 2:
The patent combines multiple detection functions into an integrated detection system where light emitters and detectors work together with cameras to simultaneously or sequentially measure x-position, y-position, and rotational orientation. The detection and correction functions are merged into a unified automated process rather than separate manual operations.
3Manufacturing precision
If the wafer stage performs multiple corrections (x-direction, y-direction, rotational), then the within-wafer uniformity improves, but the time required for alignment increases
Solution Approach 1:
The system performs all necessary alignment corrections (x-direction, y-direction, and rotational) before the ion exposure process begins. By completing the full alignment sequence in advance, the system ensures optimal within-wafer uniformity during the actual manufacturing process without requiring time-consuming adjustments during production, thereby improving uniformity while minimizing time loss.
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 improves within-wafer uniformity, reduces wafer-to-wafer process variations, and enhances device performance by accurately aligning the wafer before ion exposure, thereby minimizing defects and improving overall manufacturing consistency.
Implementation Method 1
Light emitter/detector pairs may be used to detect the x-direction misalignment and the y-direction misalignment of the wafer
Implementation Method 2
a camera and/or light emitter/detector pair may be used to detect the alignment mark, allowing for the rotational misalignment of the wafer to be determined
Data Source
AI summary
A method of correcting a misalignment of a wafer on a wafer holder and an apparatus for performing the same are disclosed. In an embodiment, a semiconductor alignment apparatus includes a wafer stage; a wafer holder over the wafer stage; a first position detector configured to detect an alignment of a wafer over the wafer holder in a first direction; a second position detector configured to detect an alignment of the wafer over the wafer holder in a second direction; and a rotational detector configured to detect a rotational alignment of the wafer over the wafer holder.