Optical Film Thickness Measurement in Substrate Processing
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Solution Overview
Problem
Current methods for measuring film thickness in the manufacturing of display panels, such as organic light emitting display devices, face challenges in accuracy and reliability, particularly due to indirect thickness calculations using techniques like quartz crystal microbalance and optical emission spectroscopy, which are sensitive to vibration and plasma states, respectively.
Innovation Solution
A substrate processing apparatus with a measurement unit that includes a light source, transmission portions, and a reception portion, allowing for real-time calculation of film thickness by irradiating light and measuring reflectance or elliptical polarization changes, ensuring accurate thickness measurement on both the measurement unit and the substrate, even in non-plasma deposition processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If indirect measurement methods like quartz crystal microbalance are used, then film thickness can be measured during deposition, but the measurement accuracy deteriorates due to sensitivity to vibration
Solution Approach 1:
The patent creates an optical copy of the film formation process by measuring reflectance changes that correspond to film thickness, rather than directly measuring the physical film. The measurement unit detects optical properties that are copied from the actual film deposition state, allowing indirect but stable measurement of thickness without being affected by vibration that would impact direct physical measurement methods.
Solution Approach 2:
The patent replaces mechanical measurement systems (like quartz crystal microbalance that physically detect mass change) with an optical measurement system. By using light reflectance and polarization changes instead of mechanical vibration detection, the system achieves measurement capability that is not sensitive to external vibrations, thereby improving reliability while maintaining measurement precision.
2Loss of time
If optical emission spectroscopy is used for thickness calculation, then real-time measurement is possible, but the measurement precision deteriorates due to plasma state sensitivity
Solution Approach 1:
The patent creates an optical copy of the film properties by measuring reflectance and polarization changes that correspond to film thickness. This optical copying method provides real-time measurement capability while being independent of plasma state variations, thereby maintaining both time efficiency and measurement precision simultaneously.
Solution Approach 2:
The patent introduces optical properties (reflectance and polarization) as intermediary measurement parameters that mediate between the film deposition process and the measurement system. These optical intermediaries provide real-time information about film thickness without being directly affected by plasma state changes, thus achieving both real-time measurement and high precision.
3Measurement precision
If a measurement unit is added to the substrate processing apparatus, then in-situ thickness measurement is enabled, but the device complexity increases
Solution Approach 1:
The measurement unit is designed with multi-functionality, serving both as a thickness measurement device and potentially as part of the deposition monitoring system. By making the measurement unit universal, the patent reduces the need for separate dedicated components, thereby enabling in-situ measurement while minimizing the increase in overall device complexity.
Solution Approach 2:
The patent merges the measurement functionality with the existing substrate processing apparatus structure. The measurement unit is integrated into the deposition chamber environment, combining measurement functions with the deposition process monitoring, which reduces the need for separate external measurement systems and thereby limits the increase in device complexity.
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 enhances the accuracy and reliability of film thickness measurement by directly calculating the thickness on the substrate based on measurements from the measurement unit, improving the precision and consistency of the deposition process.
Implementation Method 1
The controller may calculate the first thickness of the at least one deposition material deposited on the at least one transmission portion based on the second light
Implementation Method 2
The controller may calculate the first thickness of the at least one deposition material deposited on the at least one transmission portion based on a change in elliptical polarization of the at least one deposition material
Data Source
AI summary
A substrate processing apparatus includes a chamber including an accommodation space, a stage disposed in the accommodation space and provided with a substrate disposed thereon, a deposition part disposed under the stage and spraying at least one deposition material to the substrate, and a measurement part disposed adjacent to the deposition part. The measurement part includes an accommodation portion provided with an opening defined through at least one surface thereof, a light source disposed in the accommodation portion and irradiating a first light, at least one transmission portion disposed in the opening, facing the light source, and receiving the first light, and a reception portion facing the at least one transmission portion and receiving the first light reflected from the at least one deposition material as a second light.