Thin film surface stress meter

Thin film surface stress meterIt is a precision detection equipment specifically used in semiconductor manufacturing to measure the stress of thin films on wafers. Based on laser scanning technology, it is mainly used to analyze the stress distribution, curvature imaging, and residual stress parameters of thin film materials.

FLATSCANThin film surface stress meterA non-contact optical surface profiler with a large measurement range, suitable for high-precision two-dimensional or three-dimensional measurement of wafer stress (film stress), surface curvature (radius), and slope.

Optical measurement principle for surface contour measurement

FLATSCANThin film stress testerUsed for non-contact measurement of flatness, surface curvature, average radius, and film stress (wafer stress) of various reflective surfaces such as silicon wafers, mirrors, X-ray mirrors, metal surfaces, or polished polymers. The principle of optical measurement ensures high accuracy. It is based on measuring the reflection angle of a vertically incident laser beam along a line with a constant step size. The change in reflection angle between measurement points can accurately calculate the surface contour. For certain applications, the reflection angle itself (surface slope) is also important. Therefore, the software also provides this measurement option.

In the application of semiconductor technology, the film stress (wafer stress) of the coating can be calculated by measuring the curvature radius of the wafer before and after coating.

Large measurement area

One characteristic of the measurement principle used is that it is independent of the measurement area. Therefore, the standard measurement field diameter of 200mm can be increased almost arbitrarily without reducing accuracy.

High measurement accuracy

The FLATSCAN thin film stress measuring instrument has the characteristic of high measurement accuracy. The resolution of the measurement system can reach 0.1 arcsec. The reproducibility of surface shape is better than 100 nm.

Large measurement range and working distance

The measurement range refers to the maximum vector height (or minimum measurable curvature radius) that can be measured in one scan. One major feature of FLATSCAN is its extremely wide measurement range, which cannot be achieved by other competing measurement methods such as fringe interferometers or phase-shifting interferometers.

Therefore, the FLATSCAN thin film stress gauge is suitable for measuring surfaces with strong curvature, such as goebel mirrors, silicon wafers, or other similar surfaces. The optical measurement principle used is not affected by the working distance and ensures a high working distance, so there is no risk of damage to the sample.

Optional 2D/3D measurement

Depending on the device type, single line scanning or full 3D scanning can be selected. 3D scanning is composed of numerous single line scans automatically combined and has automatic sample positioning function. This software provides all the commonly used functions for excellent graphical and numerical representation of measurement results, such as 3D characterization, profile drawings, and measurement reports.

Software module for calculating membrane stress

The software is equipped with a module for calculating thin film stress based on Fowkes theory, which is suitable for semiconductor technology and all applications involving surface modification (such as coating or removal of coating), and can quickly and easily measure thin film stress. The film stress is calculated based on the average curvature radius before and after the coating process.

Main technical parameters:

1. Laser beam non-contact measurement

2. Capable of automatically measuring the contour, curvature, and film stress of wafers

3. Repeatability of surface curvature (P-V) ≤ 100nm

4. Resolution of optical measurement system: 0.1 arcsec

5. Accuracy of optical measurement system: 1 arcsec

6. Scanning speed: 10-30mm/s

7. Measurable range: standard diameter of 200mm, 300mm, larger sizes can be customized