Laser Annealing Orbit Control for Uniform Wafer Die Heating
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Solution Overview
Problem
The pattern loading effect during annealing processes in semiconductor device fabrication leads to temperature variations across semiconductor dies, resulting in inconsistent dopant activation and electrical characteristics among devices, due to differences in radiant energy absorption caused by patterning density, aspect ratio, and reflectivity variations.
Innovation Solution
A system comprising a wafer stage, a laser beam generator, and a controller that uses manufacturing information to project a laser beam onto the semiconductor die with adjustable parameters and orbits, performing a self-alignment procedure and measuring temperature to adjust the annealing process, thereby addressing the pattern loading effect by ensuring uniform heat distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional annealing processes are used, then processing speed is maintained, but temperature variations across semiconductor dies cause inconsistent dopant activation and electrical characteristics
Solution Approach 1:
The patent applies local quality by varying the laser beam parameters (power, spot size, scanning speed) across different regions of the semiconductor die to compensate for pattern loading effects. Different areas receive customized annealing conditions based on their specific pattern density and reflectivity characteristics, ensuring uniform dopant activation despite structural variations.
Solution Approach 2:
The system incorporates real-time temperature measurement and feedback control during the laser annealing process. Temperature sensors monitor the actual thermal conditions, and the control system adjusts laser parameters dynamically to maintain target temperature profiles, eliminating temperature variations that would otherwise cause inconsistent electrical characteristics.
2Ease of manufacture
If uniform laser annealing is applied across the entire die, then processing is simplified, but pattern loading effects cause temperature variations due to differences in radiant energy absorption
Solution Approach 1:
The patent transforms the static uniform annealing approach into a dynamic process where laser parameters are continuously adjusted during scanning. The system modifies power, spot size, and scanning speed in real-time based on the local pattern characteristics, enabling temperature uniformity while maintaining ease of manufacture through automated control.
Solution Approach 2:
The invention changes multiple laser parameters simultaneously (power, spot size, scanning speed) to compensate for pattern loading effects. By varying these parameters according to the local pattern density and reflectivity, the system achieves uniform temperature distribution without requiring complex manual intervention.
3Temperature
If laser parameters are adjusted to compensate for pattern loading effects, then temperature uniformity is achieved, but system complexity increases due to multiple adjustable parameters and control requirements
Solution Approach 1:
The system performs self-alignment and automatic parameter adjustment based on pre-stored layout information. The controller automatically calculates the optimal laser parameters for each region without requiring manual intervention, and the system self-corrects for pattern loading effects using the stored geometric data, reducing operational complexity despite the multiple adjustable parameters.
Solution Approach 2:
The patent stores the semiconductor die layout information and pattern characteristics in advance before the annealing process. This preliminary preparation enables the control system to pre-calculate the required laser parameter adjustments, eliminating the need for real-time complex calculations and reducing system complexity during actual operation.
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 the efficiency and accuracy of the annealing process by ensuring uniform dopant activation across the semiconductor die, reducing resistance and circuit delays, and enhancing the overall performance of semiconductor devices.
Implementation Method 1
a laser beam generator to generate a laser beam; the controller is configured to control the laser beam generator to project the laser beam onto the semiconductor die along at least one annealing orbit
Implementation Method 2
a measurement module to measure a temperature of the semiconductor die; the controller is configured to adjust the annealing process in response to the temperature
Data Source
AI summary
Systems for annealing a wafer are provided. A system includes a wafer stage, a laser beam generator, and a controller. The laser beam generator is configured to generate a laser beam. The controller is configured to control the laser beam generator according to information regarding layout of a first semiconductor die of the wafer, so as to project the laser beam with a first laser parameter onto the first semiconductor die of the wafer on the wafer stage along at least one annealing orbit. The controller is configured to arrange the annealing orbit to partially cover the first semiconductor die of the wafer and to uncover a plurality of second semiconductor dies of the wafer.