Wafer Cleaning Optics for Uniform Laser Heating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing wafer cleaning processes using batch devices face issues with temperature uniformity on the wafer surface due to air flow and reflectivity, leading to defects and poor dispersion uniformity, necessitating a conversion to single-wafer devices with laser heating, which still struggles with achieving uniform temperature across the entire surface.
Innovation Solution
A wafer cleaning apparatus that includes a rotatable chuck, a laser module for heating the wafer, and a calibration window with different light transmissivity regions to optimize laser penetration and temperature control, using an aspheric lens array and coating layers to ensure uniform heating and cleaning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a batch device is used for wet cleaning, then multiple wafers can be cleaned simultaneously, but temperature uniformity on the wafer surface deteriorates due to air flow and reflectivity
Solution Approach 1:
The patent transitions from batch processing to single-wafer processing, segmenting the cleaning process to eliminate temperature uniformity issues caused by batch processing, while maintaining productivity through rapid sequential processing
Solution Approach 2:
The patent replaces conventional heating methods with laser heating, using optical energy to achieve uniform and precise temperature control on the wafer surface, eliminating the temperature uniformity problems associated with thermal convection in batch processors
2Temperature
If a single-wafer device with laser heating is used, then temperature uniformity can be improved, but difficulty in achieving uniform temperature across the entire surface persists due to air flow and reflectivity
Solution Approach 1:
The patent modifies the optical parameters of the laser system by introducing an aspheric lens array and calibration window with specific transmissivity characteristics, changing the laser beam profile to achieve uniform energy distribution across the wafer surface
Solution Approach 2:
The patent introduces a calibration window with specific optical transmissivity as an intermediary between the laser and wafer, and an aspheric lens array to mediate the laser beam shaping, ensuring uniform energy distribution and reliable temperature control
3Device complexity
If conventional heating methods are used in single-wafer devices, then equipment complexity is reduced, but temperature uniformity deteriorates
Solution Approach 1:
The patent replaces mechanical heating systems with a laser-based optical heating system, which achieves superior temperature uniformity through non-contact energy delivery and precise beam control using aspheric lenses
Solution Approach 2:
The patent changes the fundamental heating mechanism from thermal conduction/convection to optical absorption, utilizing the wafer's optical properties to achieve rapid and uniform heating across the entire surface
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
The solution improves temperature uniformity and cleaning performance across the entire wafer surface, enhancing the fabrication of semiconductor devices by maintaining consistent laser intensity and temperature distribution.
Implementation Method 1
a laser module configured to irradiate a lower surface of the wafer with a laser
Implementation Method 2
irradiating a lower surface of the wafer with a laser to heat the wafer
Implementation Method 3
an aspheric lens array configured that the laser is transmitted through the optical system between the laser module and the wafer
Implementation Method 4
a first coating layer and a second coating layer having different light transmissivities from each other
Data Source
AI summary
A wafer cleaning apparatus, a method of cleaning wafer and a method of fabricating a semiconductor device are provided. The method of fabricating the semiconductor device includes disposing a wafer on a rotatable chuck, irradiating a lower surface of the wafer with a laser to heat the wafer, and supplying a chemical to an upper surface of the wafer to clean the wafer, wherein the laser penetrates an optical system including an aspheric lens array, the laser penetrates a calibration window, which includes a first window structure including a first light projection window including first and second regions different from each other, a first coating layer covering the first region of the first light projection window, and a second coating layer covering the second region of the first light projection window, and the first coating layer and the second coating layer have different light transmissivities from each other.