Optical Heating Device Uniform Temperature Control
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Solution Overview
Problem
Existing optical heating devices for semiconductor wafers face challenges in achieving uniform temperature distribution due to non-uniform light irradiance from multiple light sources, requiring manual adjustment based on operator experience and intuition, which can lead to inconsistencies in semiconductor device characteristics.
Innovation Solution
An optical heating device with a controller that adjusts the light output of multiple planar light source areas based on pre-measured temperature distribution characteristic information and desired temperature distribution, allowing for automatic correction of temperature discrepancies across the wafer surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple light sources are arranged to heat the wafer surface, then heating coverage is improved, but temperature distribution uniformity deteriorates due to light concentration near the center
Solution Approach 1:
The patent applies local quality by assigning different light output characteristics to different regions of the light source array. Specifically, light sources in the central region are configured with lower light output compared to those in peripheral regions, creating spatially varying heating characteristics that compensate for the natural light concentration effect and achieve uniform temperature distribution across the wafer surface
Solution Approach 2:
The patent employs asymmetry by intentionally creating an asymmetric light output distribution pattern where peripheral light sources emit more strongly than central light sources. This asymmetric configuration counteracts the symmetric geometric arrangement of the light sources, transforming the naturally concentrated central heating into a uniform temperature field across the entire wafer surface
2Temperature
If light source output is manually adjusted based on operator experience, then temperature uniformity can be improved, but automation level and consistency deteriorate
Solution Approach 1:
The patent implements preliminary action by pre-configuring the light source array with specific output characteristics before the heating process begins. The light sources are pre-adjusted to have different output levels based on their positions, with peripheral sources set to higher output and central sources to lower output. This preliminary configuration enables automatic uniform temperature distribution without requiring real-time manual intervention during operation
Solution Approach 2:
The patent applies parameter changes by modifying the light output parameter of individual light sources based on their spatial position. The system changes the operational parameters of the light sources from a uniform initial state to a position-dependent varied state, where each light source operates at an optimized output level to achieve uniform temperature distribution across the wafer 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 device achieves accurate and automatic temperature uniformity on semiconductor wafers by dynamically adjusting light source outputs, reducing reliance on operator experience and ensuring consistent device characteristics.
Implementation Method 1
optical heating, which enables non-contact treatment, is generally employed. For example, Patent Document 1 below discloses a heat treatment device for performing heat treatment of silicon wafers by irradiating the surface to be treated of a semiconductor wafer with heating light
Data Source
AI summary
An optical heating device includes a heating light source unit having a plurality of planar light source areas in each of which a light source is arranged, and a controller configured to control light output of the light source. The controller includes a storage section that stores temperature distribution characteristic information describing a relation between a relative ratio of the light output of each light source and temperature distribution on a main surface of a tabular test piece, when light from the heating light source unit is irradiated toward the tabular test piece; and an output controller that changes a ratio of the light output based on the temperature distribution characteristic information, in order to bring the temperature distribution of a main surface of an object to be heated obtained when the light is irradiated under a predetermined light output for distribution measurement closer to a desired temperature distribution.