VCSEL Heater Block Layout for Uniform Substrate Heating
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Solution Overview
Problem
Conventional substrate heating devices using halogen lamps struggle with temperature measurement accuracy and uniformity due to the translucent nature of silicon wafers at low temperatures and the inability to divide control areas, leading to non-uniform heating and potential substrate damage.
Innovation Solution
A heater block comprising a first and second laser module with independently controlled areas, each supplied by separate power sources, and a reflector unit to direct light, combined with pyrometers for precise temperature measurement, allowing for subdivided control of heating zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If halogen lamps are used for substrate heating, then heating capability is provided, but temperature measurement accuracy deteriorates due to light transmission through translucent silicon wafers
Solution Approach 1:
The patent changes the wavelength parameter of the light source from halogen lamp (broad spectrum including 0.9-1μm) to VCSEL laser (specific wavelength outside measurement band). By selecting a laser wavelength that does not overlap with the pyrometer's measurement wavelength band, the interference from light transmission through the substrate is eliminated, enabling accurate temperature measurement even at low temperatures where silicon is translucent.
2Manufacturing precision
If halogen lamps are used as single control unit, then heating is provided, but temperature uniformity across substrate areas deteriorates due to inability to divide control areas
Solution Approach 1:
The patent divides the heating system into multiple independent VCSEL laser modules, each capable of being controlled separately. This segmentation allows different regions of the substrate to be heated to different temperatures independently, enabling precise temperature uniformity control across the entire substrate surface. Each laser module can be adjusted based on the specific thermal requirements of its corresponding substrate region.
Solution Approach 2:
The patent implements dynamic control of each VCSEL laser module's power output based on real-time temperature feedback from pyrometers. The power supply to each module can be independently adjusted during the heating process, allowing the system to adapt to changing thermal conditions and maintain optimal temperature uniformity throughout the substrate.
3Manufacturing precision
If VCSELs are divided into multiple control areas with independent power supply, then temperature uniformity is improved, but device complexity increases
Solution Approach 1:
The power supply system is segmented into multiple independent power sources, each dedicated to a specific VCSEL laser module or control area. This segmentation allows for independent control and optimization of each region's power consumption, enabling precise temperature management while maintaining manageable system complexity through modular architecture.
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 enhances temperature uniformity and accuracy, reduces power consumption, and prevents substrate damage by using VCSELs to control heating zones independently, ensuring reliable low-temperature processes.
Implementation Method 1
a first laser module having a plurality of laser cells; a second laser module having a plurality of laser cells and disposed around the first laser module
Implementation Method 2
The pyrometer may collect radiant energy emitted from the substrate and measure the temperature of the substrate in a non-contact manner based on a black body radiation temperature relationship
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3(a)~3(b)
AI summary
The present invention relates to a heater block capable of precise control of a heating temperature and a substrate device including the heater block. The heater block may include: a first laser module having multiple laser cells; a second laser module which has multiple laser cells and is provided around the first laser module; and a first and a second power source part for independently supplying power to the first laser module and the second laser module, respectively, wherein, at least one among the first laser module and the second laser module is divided into multiple control areas each of which includes the one or more laser cells sharing an input terminal to which power is input, and the multiple control areas are controlled independently from each other.