LSI-TG
Tunable Laser Thickness Measurement System
Non-contact, non-destructive thickness measurement system using a tunable laser.
Capable of measuring objects more than 1 meter away in real-time. Ideal for integration into production lines.
LSI-TG is a thickness measurement system that uses a tunable laser as its medium. As the medium is light, it is fundamentally non-contact and non-destructive (excluding photosensitive materials that change with light exposure). The use of a laser as the light source provides strong penetration power, enabling measurement of relatively thick samples. In actual applications, we have measured samples with an optical thickness of about 3mm.
The system offers high real-time measurement capability and is widely adopted for production control during manufacturing. As it is often integrated into existing production lines, we can customize various output formats. The most commonly delivered systems output OK/NG judgments or processing completion signals to PLCs, but we can also output via DIO instead of PLC, or output thickness as voltage.
Features
Non-contact & Non-destructive Measurement
Light-based measurement causes no damage to samples.
Measure Objects 1m+ Away
Long working distance enables installation above production equipment.
Ideal for Production Lines
Real-time measurement enables use in production management and process control.
Measure Layers Up to Several mm (Optical Thickness)
Strong penetration power excels at measuring thick samples.
High-speed Measurement (Thousands per Second)
Fast wavelength variation enables real-time thickness monitoring.
Compatible with High-doped Si Wafers
Can measure high-concentration dopant samples such as P++.
Technical Details
Real-time Measurement and Production Management
LSI-TG is a non-contact, non-destructive real-time thickness measurement system using laser technology. Its non-contact real-time thickness measurement capability makes it suitable for integration into wafer and film manufacturing processes. The laser-based measurement medium provides high penetration power for thick sample measurement, and enables measurement at long working distances (WD).
In practice, we have measured Si wafers approximately 800μm thick from points more than 1m away in real-time. However, the wavelength variation range of lasers that can rapidly change wavelength is narrower compared to visible light measurement, making it unsuitable for thin samples. Therefore, samples below 10μm in Si-equivalent thickness cannot be measured. For measuring thin objects such as coating layers, please use our WSI-TG.
High-doped Sample Compatibility
LSI-TG's ability to handle high-doped samples is one of its strengths. Generally, higher dopant concentrations increase the extinction coefficient, making electromagnetic thickness measurement including optical methods more difficult. At certain dopant concentrations, contact-type gauges become the standard, but contact methods risk damaging samples unless stationary measurements are made. However, LSI-TG uses light with strong penetration power to capture the small amount of light that does penetrate high extinction coefficient environments, combined with proprietary innovations that highly cancel strong surface reflections, enabling thickness measurement even on high-concentration dopant Si wafers commonly called P++.
System Configuration
The system consists of a control PC, core unit, and probe. The control PC and core unit are each 3U 19-inch racks, with a typical system delivery consisting of a combined 6U 19-inch rack and probe.
The probe receives the laser reflected from a sample 1m away, so it is mounted on a stage with fine adjustment capability. This results in a size of approximately 100x100x150mm (excluding control knobs) for the stage with a cylindrical probe attached. However, this is for long WD applications; for short WD use, a cylindrical probe with simple mounting fixture can be used.
Customization Support
LSI-TG customization primarily involves probe fixtures adapted to WD and installation environment, as well as output formats and interfaces. As it is often installed on existing factory equipment, most customization involves matching to production equipment interfaces.
For example, the system receives a processing start signal to begin thickness monitoring, then sends signals to production equipment via PLC or DIO when processing recipe change thickness or processing completion thickness is reached.
Main Applications
Demo Equipment Rental Available
For samples with high measurement difficulty, we can receive them and study measurement recipes.
If you are considering a thickness measurement system, especially for integration into production lines,
and your target layer is in the 3μm to 5mm optical thickness range (refractive index × actual thickness) with double-sided mirror finish, there is a high probability that LSI-TG can measure it.