Semiconductor Light Heating for Uniform Wafer Temperature
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Solution Overview
Problem
Existing heating systems for semiconductor processing, such as those used for OLED and LED fabrication, face challenges in achieving homogeneous temperature distribution across large areas, leading to variations in growth conditions and device characteristics, and are not reliable enough to maintain precise temperatures above 1000°C without significant power requirements or mechanical complexity.
Innovation Solution
A heating system utilizing multiple semiconductor light sources, specifically Vertical Cavity Surface Emitting Lasers (VCSELs), to heat a processing surface by illuminating it with overlapping light from at least 50 sources, ensuring a homogeneous temperature distribution by averaging out intensity differences and providing reliable high-temperature heating without the need for complex mechanical devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional heating systems are used to heat semiconductor wafers, then heating capability is achieved, but homogeneous temperature distribution cannot be maintained
Solution Approach 1:
The heating system is segmented into multiple independent semiconductor light sources (VCSELs) arranged in arrays, where each light source independently contributes to heating specific regions of the wafer. This segmentation allows precise local temperature control and achieves homogeneous overall temperature distribution through coordinated operation of multiple sources.
Solution Approach 2:
The patent replaces conventional mechanical heating systems (heating plates, contact heaters) with optical heating using semiconductor light sources. This substitution eliminates mechanical contact issues, improves temperature distribution homogeneity, and enables non-contact heating with superior control reliability.
2Temperature
If high power is used to maintain temperatures above 1000°C, then processing temperature is achieved, but power requirements become excessive
Solution Approach 1:
The system changes the heating parameter from conventional thermal conduction to optical absorption. Semiconductor light sources emit specific wavelengths that are efficiently absorbed by the wafer material, converting optical energy directly to thermal energy with high efficiency. This parameter change reduces overall power consumption while maintaining processing temperatures above 1000°C.
3Temperature
If conventional heating systems are used, then heating function is provided, but temperature homogeneity deteriorates across large areas
Solution Approach 1:
The heating system uses multiple semiconductor light sources arranged in arrays that can be independently controlled. Each light source heats a specific region, and by coordinating the intensity and distribution of multiple sources across large areas, homogeneous temperature distribution is achieved even over large wafer surfaces.
Solution Approach 2:
The system applies local quality control by allowing each semiconductor light source to independently adjust its output to match the specific heating requirements of different regions on the wafer. This enables precise local temperature control that maintains overall homogeneity across large processing areas.
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 system achieves a highly homogeneous temperature distribution across the processing surface, with temperature deviations less than 0.5%, enabling consistent semiconductor layer growth and processing at temperatures up to 1000°C with reduced power requirements and improved reliability, even when using medium-power semiconductor light sources.
Implementation Method 1
The optical energy provided by the semiconductor light sources heats a processing surface to the desired temperature
Implementation Method 2
Semiconductor light sources like Vertical Cavity Surface Emitting Lasers are used to illuminate the heating surface of the object
Data Source
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AI summary
The invention describes a heating system (100) and a corresponding method of heating a heating surface (180) of an object (150, 950) to a processing temperature of at least 100°C, wherein the heating system (100) comprises semiconductor light sources (115), and wherein the heating system (100) is adapted to heat an area element of the heating surface (180) with at least 50 semiconductor light sources (115) at the same time. The heating system (100) may be part of a reactor for processing semiconductor structures. The light emitted by means of the semiconductor light sources (115) overlaps at the heating surface (180). Differences of the characteristic of one single semiconductor light source (115) may be blurred at the heating surface (180) such that a homogeneous temperature distribution across a processing surface of a, for example, wafer may be enabled.