Confocal profilers have been developed for measuring smooth to very rough surfaces. Confocal profiling provides the highest lateral resolution, up to 0.15 um line & space, with spatial sampling can be reduced to 0.01 μm, which is ideal for critical dimension measurements.
Confocal technology is able to measure the surface height converting conventional images into optical sections where the signal is preserved for those areas within the depth of focus of the objective, improving the image contrast and the lateral resolution and system noise.
For 3D imaging it is necessary to obtain data from all the pixels of the camera. That means: to reconstruct a confocal image. To do that, the multiple slit image is shifted one pixel as many times as necessary to fill the camera. In each of the shifted multiple slits, one image of the camera is taken and the confocal algorithm is applied on the pixels illuminated at that moment.
No moving parts in the optical set-up
The confocal scanning technique implemented in Sensofar’s systems is a Microdisplay Scan Confocal Microscope (according to ISO 25178 part 607). The microdisplay creates a rapidly switching device with no moving parts, making data acquisition fast, reliable and accurate. Due to this and the associated algorithms, Sensofar’s Confocal technique yields a class-leading vertical resolution, better than other Confocal approaches.
Read our related paper Confocal Fusion: Towards the universal optical 3D metrology technology
Don’t stop me now! Continuous Confocal
Revolutionary step in Confocal measurement technology, steadily reducing the acquisition time by a factor of 3. Continuous Confocal mode avoids the discrete (and time-consuming) plane-by-plane acquisition of classical Confocal by simultaneously scanning in-plane and Z axis. Essential for reducing acquisition times for large area scans and large Z scans.
Confocal profiling provides the highest lateral resolution, up to 0.15μm line & space, with spatial sampling can be reduced to 0.01 μm, which is ideal for critical dimension measurements. High NA (0.95) and magnification (150X) objectives are available to measure smooth surfaces with steep local slopes over 70° (for rough surfaces up to 86°).
Best lateral resolution: 300 nm (Rayleigh criteria)
Slopes up to 70º for smooth surfaces and 86º for rough surfaces
Continuous confocal: speed comparable to AiFV
High repeatability, down to 1 nm system noise
Thickness measurements from 1.5 μm to several mm
Highest level of flexibility