Manufacturing solar cells and solar panels involves the precise layering of materials including glass, semiconductors, metals, and antireflective coatings.
Subjecting them to many sophisticated etching, bonding and electrochemical processing steps is also part of the process. Yield is critical, and Photoluminescence optical inspection is an important tool to allow selection of highest efficiency wafers which will later be processed and built into panels.
Photoluminescence techniques can also be used with modulated light source / panel operation to carry inspection on installed panels during day light.
Hyperspectral imaging (HSI) is a technique that analyses a wider spectrum of light instead than just assigning primary colours (red, green, blue) to each pixel.
The light striking the pixels in an array is broken down into many different spectral bands in order to provide reflectance information on what is being imaged. Hyperspectral imaging provides identification of materials and specific chemicals thanks to the unique spectral signatures acquired by the pixels generating the image of a scene.
Hyperspectral is useful technique for food and plastic sorting as well as for crop and geological surveys.
X-ray cameras are used to detect porosity, inclusions, cracks and even grain structure within a variety of cast components and in welded joints.
With the increasing production of many new types of components such as BGA and flip-chip devices, it is important to produce good quality, real-time, X-ray images to isolate dry joints, bridging/shorts, voiding, misplacement and misalignment problems down to few microns or less resolution.
A high-resolution camera can be used in conjunction with high geometric magnification in order to keep a system that includes moving stages compact. The same kind of set up can be used for inspection of the latest ceramic, plastic and composite structures as well. The latest cameras released by PSEL will typically achieve better than 25 microns minimum feature detection without geometric magnification thus allowing compact design and large field of view coverage.
Simultaneous read out and exposure cycles are used for keeping the duty cycle as close as possible to 100%, thus enabling the highest PCB/sample inspection throughput.
The semiconductor industry roadmap uses shorter wavelength light sources to produce smaller feature sizes on processors as well as on memory components.
Wavelengths ranging from 248 nm to 193 nm are currently used to produce feature sizes < 100 nm. The next generation includes EUV sources which use 13.5 nm for printing feature size as small as 32 nm. A source with very good brightness is needed for maintaining production throughput similar to that of DUV techniques. Therefore, EUV and UXV CMOS detectors with good UV sensitivity and good dynamic range are necessary to cope with pulsed sources that are used to characterise resin, prior to mask manufacturing. EUV sources can produce an large amount of debris so it is important that that the CMOS detectors withstand over exposures without saturation / bleeding artefacts as well as the potential contamination from debris coming from the plasma generation.
InGaAs cameras are used to characterise the profiles of lasers used in the telecom bands as well those used for free space communication.
Moments, divergence and wavelength emissions can be precisely determined using a set of motorised stages and spectrometer combined with a high-resolution camera
UV sensitive CMOS cameras are used for recording the UV reflectance of untreated fingerprints, as well as fingerprints that have been processed with cyanoacrylate fuming (superglue evaporation).
Good sensitivity is often required for detecting faint luminol-treated stains. The cameras are used with a narrow band pass filter which will select the UV response only above the visible background light.
High resolution sensors, typically over 4.2 megapixel, are required for sampling specific finger print details. Image enhancement tools like Fast Fourier Transform and image subtraction that allow you to quickly identify your images can also be utilised.