Transmission Pyrometry for Uniform Substrate Temperature Control
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Solution Overview
Problem
Current semiconductor processing techniques face challenges in achieving uniform and repeatable film formation due to variations in local substrate temperature, gas flows, and precursor concentrations, which complicates the control of substrate temperature and layer formation conditions.
Innovation Solution
A substrate processing apparatus with a vacuum chamber and thermal lamps, where radiation sensors measure temperatures at different zones of the substrate, and a controller adjusts power to the lamps based on these measurements to maintain uniform temperature control, using a transmission pyrometry system to accurately measure substrate temperature by directing radiation through the substrate and comparing intensities at discrete wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If heat lamps are positioned outside the process chamber to avoid contaminants, then contamination is minimized, but temperature control precision deteriorates due to thermal absorption and emission by chamber components
Solution Approach 1:
The patent divides the heating function into multiple independent heating zones with separate control, allowing precise temperature management in different regions of the substrate. This segmentation enables accurate temperature control while maintaining the benefit of external lamp positioning by reducing the impact of thermal interference from chamber components.
Solution Approach 2:
The patent implements a feedback control system using radiation sensors to continuously monitor substrate temperature and adjust heating power accordingly. This feedback mechanism compensates for thermal absorption and emission variations, maintaining precise temperature control despite the external positioning of heat lamps and the presence of chamber components.
2Measurement precision
If radiation sensors are exposed to film forming conditions inside the process chamber to measure substrate temperature, then temperature measurement capability is improved, but sensor reliability deteriorates due to exposure to harsh processing environment
Solution Approach 1:
The patent uses a transparent window as an intermediary medium that allows radiation from the substrate to pass through to the sensor while keeping the sensor isolated from the harsh process environment. This intermediary enables temperature measurement capability without exposing the sensor directly to film-forming conditions, thus maintaining both measurement precision and sensor reliability.
3Manufacturing precision
If multiple heating zones are implemented to improve temperature uniformity across the substrate, then temperature distribution homogeneity is improved, but device complexity increases
Solution Approach 1:
The patent segments the heating system into multiple independently controllable zones, each with its own radiation sensor and power adjustment capability. This segmentation achieves superior temperature uniformity across the substrate by allowing localized temperature control, while the modular design manages complexity through standardized control architecture.
Solution Approach 2:
The patent applies local quality control by allowing different regions of the substrate to be heated to different temperatures based on specific process requirements. Each heating zone can be independently optimized for its local temperature needs, achieving overall temperature uniformity while accommodating local variations in heating requirements.
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 enables precise temperature control, minimizing temperature anomalies and ensuring uniform film thickness and composition, thereby improving the repeatability and quality of semiconductor films.
Implementation Method 1
A plurality of thermal lamps is positioned external to the processing region... transmitting radiation from a plurality of lamps through the window... heating a substrate disposed on a substrate support in a chamber having a window by transmitting radiation from a plurality of lamps through the window
Implementation Method 2
A radiation sensor is disposed on the side of the substrate support opposite the plurality of thermal lamps to receive emitted radiation from the radiation source... using a transmission pyrometry system to accurately measure substrate temperature by directing radiation through the substrate and comparing intensities at discrete wavelengths
Implementation Method 3
A reflective member may be positioned to direct radiation from the radiation source disposed within the sidewall toward the radiation sensor
Data Source
AI summary
Implementations disclosed herein relate to methods and apparatus for zoned temperature control during a film forming process. In one implementation, a substrate processing apparatus is provided. The substrate processing apparatus comprises a vacuum chamber, a plurality of power supplies coupled with the plurality of thermal laps and a controller that adjusts the power supplies based on input from radiation sensors. The chamber includes a sidewall defining a processing region. A plurality of thermal lamps is positioned external to the processing region. A window is positioned between the plurality of thermal lamps and the processing region. A radiation source is disposed within the sidewall and oriented to direct radiation toward an area proximate a substrate support. A radiation sensor is disposed on the side of the substrate support opposite the plurality of thermal lamps to receive emitted radiation from the radiation source.