Substrate Tuning via Spatial Light Projection for Thermal Uniformity
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Solution Overview
Problem
Conventional hotplates in semiconductor fabrication processes have temperature uniformity limitations of about 0.1 degrees Celsius, which is insufficient for preventing defects as semiconductor devices scale down, necessitating improved temperature control for precise heating and cooling.
Innovation Solution
A system that combines spatially-controlled light projection with hot plate heating, using UV or infrared light to achieve temperature uniformity within 0.02 degrees Celsius by modulating light intensity and wavelength, allowing for precise control of substrate temperature through pixel-based light patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional hotplate heating is used, then substrate heating function is provided, but temperature uniformity is limited to about 0.1 degrees Celsius
Solution Approach 1:
The patent applies local quality by using an optical projection system to deliver different light intensities to different locations on the substrate. The projection system can concentrate light energy on specific regions that require additional heating, while leaving other regions with standard hotplate heating, thereby creating locally optimized temperature distribution across the substrate surface
Solution Approach 2:
The patent introduces light energy as an intermediary medium between the hotplate and the substrate. The optical projection system acts as a mediator that modulates thermal energy delivery by converting light intensity patterns into localized heating effects, enabling precise temperature control without direct contact between the hotplate and substrate surface
2Reliability
If temperature uniformity is improved to within 0.02 degrees Celsius, then defectivity is reduced, but system complexity increases due to optical projection requirements
Solution Approach 1:
The patent achieves multi-functionality by using the optical projection system for dual purposes: it serves both as a heating mechanism to improve temperature uniformity and as a patterning tool that can selectively treat different regions of the substrate. This universal approach allows a single system to address multiple process requirements without adding separate dedicated equipment for each function
Solution Approach 2:
The patent utilizes parameter changes by varying the intensity, wavelength, and spatial distribution of projected light to achieve different heating effects. By adjusting optical parameters such as light intensity patterns and exposure duration, the system can dynamically control temperature profiles to prevent defects while maintaining process flexibility
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 significantly reduces defectivity in semiconductor fabrication by providing enhanced temperature uniformity and flexibility in meeting design specifications, enabling continued scaling of semiconductor devices.
Implementation Method 1
Typical hotplates can include one or more heating elements or zones to uniformly heat a substrate positioned thereon
Implementation Method 2
A wavelength of 400-700 nm light, Ultra Violet Light (UV), infrared light, or any wavelength directed at an object can produce heat on the impact site of projected light
Data Source
AI summary
Techniques herein include systems and methods that provide a spatially-controlled or pixel-based projection of light onto a substrate to tune various substrate properties. A given pixel-based image projected on to a substrate surface can be based on a substrate signature. The substrate signature can spatially represent non-uniformities across the surface of the substrate. Such non-uniformities can include energy, heat, critical dimensions, photolithographic exposure dosages, etc. Such pixel-based light projection can be used to tune various properties of substrates, including tuning of critical dimensions, heating uniformity, evaporative cooling, and generation of photo-sensitive agents. Combining such pixel-based light projection with photolithographic patterning processes and/or heating processes improves processing uniformity and decreases defectivity. Embodiments can include using a digital light processing (DLP) chip, grating light valve (GLV), or other grid-based micro projection technology.