Thin film technology has a very wide range of applications in fields such as semiconductors, solar cells, flat-panel displays, and optical coatings. Film thickness measurement is an important aspect of testing the microstructure of thin film surfaces. With the rapid development of precision testing technology, the accuracy requirements for measuring film thickness and surface quality are becoming increasingly stringent. Traditional mechanical and electromagnetic measurement methods can no longer keep up with the times. In the future, optoelectronic technology, with its advantages of non-contact, non-destructive, and high efficiency, will continue to lead the field of film thickness measurement. Advanced optoelectronic equipment and intelligent algorithms will be used to accurately measure thin film thickness and surface quality, aiding in process optimization and product upgrading, and promoting industrial innovation and development.
1. Principle Introduction
This article introduces a method for measuring film thickness using a reflective spectroscopy system. This system utilizes the principle of interference spectroscopy, with a simple structure and high sensitivity, making it suitable for measuring the surfaces of weakly reflective, transparent, or semi-transparent films.
As shown in the figure above, the light emitted by the light source is directed at the film being measured through a fiber optic probe. The light enters the film from the air, equivalent to light entering a denser medium from a rarer one, and two reflected beams are generated on the upper and lower surfaces of the film. The first reflection occurs at the air-film interface, forming the first reflected light. The refracted light that enters the film is then reflected at the interface between the bottom of the film and the carrier, and the reflected light passes through the film and enters the air, forming the second reflected light. These two reflected lights are then transmitted through the receiving fiber and finally collected by the spectrometer. Due to the optical path difference between the two reflected lights, a spectrum similar to interference fringes is formed. The film thickness d can be calculated using the incident angle, refractive index n, and the spectral data of the peaks and valleys by the extremum method. The thicker the film, the denser the spectral data; the longer the wavelength, the sparser the spectral data. The appropriate wavelength range and spectral resolution should be selected according to the situation.
2. System Characteristics
The described system can not only measure the thickness of the thin film but also the uniform distribution of the film thickness. Compared to other methods, this method has the following advantages:
● Efficient and Convenient Data Processing: Interference spectroscopy technology does not require the detection of interference fringes and can measure at any position, enabling real-time analysis and high-precision film thickness data presentation.
● Non-contact and Non-destructive Measurement: It avoids the risk of surface scratches or contamination that may be caused by traditional contact measurements, making it especially suitable for precision components and materials with high surface quality requirements.
● Ingenious Fiber Optic Probe Design with High Adaptability: The equipped fiber optic probe is small and highly flexible, easily navigating narrow spaces to perform precise measurements inside equipment.
● Wide Measurement Range and High Precision: Interference spectroscopy for film thickness measurement has a broad range, covering film thickness from nanometers to micrometers or even larger, meeting the diverse needs of different application scenarios. It also captures minute thickness variations with high accuracy.
● High Repeatability and Stability: This technology offers excellent repeatability and stability, maintaining the accuracy and consistency of measurement results even during long-term continuous measurement or under harsh environmental conditions.
In summary, interference spectroscopy for film thickness measurement, with its efficient data processing capability, non-contact and non-destructive detection, ingenious probe design, wide measurement range and high precision, as well as high repeatability and stability, shows great application potential and value in both scientific research and industrial fields. This technology is easy to integrate with automation equipment and control systems, enabling the automation and intelligence of the measurement process. By seamlessly interfacing with other equipment, it can create an efficient real-time online production monitoring and quality control system, further enhancing production efficiency and product quality.
3. Application Fields
● Semiconductor Industry: Controlling thin film thickness is crucial for chip manufacturing. In integrated circuit manufacturing, it is necessary to precisely control the thickness of oxide and metal layers to ensure the performance and stability of devices.
● Coating Industry: Film thickness testers can be used to measure the dry film thickness of coatings. Appropriate coating thickness helps improve the protective performance, aesthetics, and durability of the coating.
● Optical Field: Measuring the thickness of optical coatings, such as silicon dioxide and calcium fluoride films in the precision optics industry. The thickness of optical coatings directly affects the performance of optical components, such as reflectivity, transmittance, and dispersion.
● New Energy/Photovoltaic Industry: In the new energy and photovoltaic industry, film thickness measurement is used to measure the thickness of films such as perovskite and ITO. Precise control of film thickness is crucial for improving the photoelectric conversion efficiency and stability of photovoltaic devices.
● Display Panel Industry: Film thickness measurement instruments are used to measure the thickness of coating films, microchannels, and other films. The thickness of these films directly affects the display effect and performance of display panels.
● Polymer Materials Industry: In the polymer materials industry, film thickness measurement can be used to measure the thickness of polymer films such as PI film. The thickness of these films significantly impacts their performance and application effects, such as permeability, barrier properties, and mechanical strength.
● Scientific Research and Universities: Film thickness measurement is used to study the growth process of new material films and explore the properties of new materials.
In summary, film thickness measurement has wide applications in many fields. Its accuracy and stability are crucial for ensuring product quality, enhancing performance, and advancing research progress.
4. Product Recommendation
Jinsp's miniature fiber optic spectrometer is very suitable for film thickness measurement applications. For more details, please visit the following link: Fiber Optic Spectrometers - JINSP Company Limited (jinsptech.com)
● Excellent performance, good reliability, and high cost-performance ratio.
● Compact size, suitable for in-situ rapid real-time monitoring.
● Easy-to-use software, simple operation.
● UV, visible, near-infrared, spectrum covering 185~2500nm, capable of fast full-spectrum measurement.
Post time: Jul-05-2024