Emissivity-Corrected Pyrometry for Stable Multilayer Deposition
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Solution Overview
Problem
Existing temperature measurement methods during thin-film deposition in semiconductor manufacturing suffer from significant oscillations due to incomplete emissivity correction, leading to inconsistent substrate temperatures and impaired reproducibility of multilayer structures, particularly in GaN (AlGaN) material systems on silicon, affecting the performance and yield of electronic components.
Innovation Solution
Simultaneously measure emissivity and reflectance values during the deposition of a multilayer structure's first section, calculate a correction value in situ, and use it to correct the actual temperature measurement during the deposition of the second section, optimizing the temperature control process to minimize oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If emissivity-corrected pyrometry is used during thin-film deposition, then temperature measurement accuracy is improved, but measurement precision deteriorates due to oscillations caused by incomplete emissivity correction
Solution Approach 1:
The patent applies preliminary action by determining the correction value during the deposition of the first section (buffer layers and transition layers) before depositing the second section (active layers). This preliminary determination of emissivity correction parameters during less critical deposition phases enables accurate temperature control during subsequent critical deposition phases without requiring real-time iterative correction during the entire process.
Solution Approach 2:
The patent segments the multilayer structure deposition into distinct sections: a first section comprising buffer layers and transition layers where the correction value is determined, and a second section comprising active layers where the corrected temperature measurement is applied for precise control. This segmentation allows the correction methodology to be optimized for different functional requirements of different layer types.
2Measurement precision
If separate deposition processes are used to determine correction values, then measurement precision is improved, but productivity deteriorates due to additional process steps
Solution Approach 1:
The patent merges the correction value determination process with the actual multilayer structure deposition process. Instead of performing separate calibration depositions, the methodology utilizes the deposition of the first section (buffer and transition layers) to simultaneously achieve both structural formation and emissivity correction parameter determination. This integration eliminates dedicated calibration steps while maintaining correction accuracy.
Solution Approach 2:
The deposition process serves dual purposes: it creates the functional multilayer structure while simultaneously providing the data needed for emissivity correction. The first section deposition inherently provides the optical properties information required for correction, making the process self-sufficient without requiring external calibration procedures.
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 reduces temperature oscillations to minimal levels, ensuring consistent substrate temperatures and improving the reproducibility of multilayer structures, enhancing the production of high-quality electronic components like transistors.
Implementation Method 1
The non-contact pyrometry method utilizes the relationship between the thermal radiation emitted by the hot object and the object's temperature, a relationship described by Planck's radiation equation
Implementation Method 2
using the actual value, a heating device for tempering the substrate against a setpoint temperature of the broad side of the substrate is controlled
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a device and a method for coating a substrate (22) with a multi-layer structure (21) which has layers of a first portion (18) and layers of a second portion (19) that are deposited on the layers of the first portion. During the deposition of at least one layer of the second portion, at least one optical measuring apparatus (10, 11) measures an emissivity value (E) and a reflectance value (R) on the broad side of the substrate (22), which broad side comprises the layer. Using a previously determined correction value (γ), an actual value (Tc) of a temperature of the broad side of the substrate (22) is calculated and, using the actual value (Tc), a heating apparatus (5) is controlled in order to control the temperature of the substrate (22) against a target value (Ts) of the temperature of the broad side of the substrate (22). It is essential that the correction value (γ) is determined during the deposition of the first portion (18), which is carried out directly before the deposition of the second portion (19).