Application of Short Wave Infrared (SWIR) Technology in the Semiconductor Industry

Short-wave infrared (SWIR) cameras can detect invisible product defects and specific material characteristics, opening up a wide range of application spaces for machine vision solutions: most short-wave infrared cameras are equipped with InGaAs (indium gallium arsenide) sensors with a detection wavelength of 900 Between nm and 1,700 nm, traditional CCD or CMOS cameras can only detect light with wavelengths below about 1050 nm.

Today, the semiconductor industry has developed into one of the largest industries in the world, and its growth momentum has continued unabated. Wafer integrated circuit (IC or chip) production is the core business of this industry.

A short-wave infrared camera equipped with an InGaAs sensor can achieve spectral imaging with a wavelength of approximately 1,150 nm through semiconductor materials (such as silicon (Si)), which has become essential equipment for the inspection process. Transmissive imaging of silicon wafers is a non-destructive inspection method that provides many benefits to the production process. Now the semiconductor industry has introduced InGaAs cameras into testing, inspection, and quality control systems.

Silicon crystal and ingot (also called crystal brick) inspection is one of the typical applications of InGaAs cameras in the semiconductor industry. InGaAs cameras can image the transmittance spectrum (wavelength range greater than 1,150 nm) of silicon-based materials. It is an ideal solution for detecting impurities that may accumulate in crystals or ingots during the production process.

Ingots need to be cut into wafer slices with a special diamond dicing knife. In this process, the purity of the wafer is very important. Even if the wafer sheet contains only a small piece of metal and other inclusions, it may cause the expensive diamond cutter to break and be scrapped. The replacement of tools not only requires costs but also leads to a decline in production efficiency and profits. The introduction of short-wave infrared cameras can avoid this problem and ensure the smooth progress of the production process.

Another important application of short-wave infrared cameras is wafer inspection. In the wafer production process, particulate matter may appear on the top, bottom, or even inside or between the wafers. A CCD or CMOS camera can detect particles on the top and bottom, while an InGaAs camera can detect particles between two bonded wafers through the silicon-based material.

InGaAs cameras can also be used for wafer packaging, that is, to detect whether the arrangement of the backside of the wafer is aligned with the front side. Shortwave infrared technology can help align the layers of the wafer and align the wafer substrate and other sub-products, such as ICs, memory cells, or transistors.

From silicon crystals to ingots/tiles, wafers, solar cells, and even solar modules, short-wave infrared camera applications can cover the entire photovoltaic power supply chain inspection process. Since InGaAs cameras can realize light-transmitting imaging of silicon-based materials, it is the most effective solution for detecting physical defects inside silicon-based materials.

In addition to the newly emerging short-wave infrared imaging inspection technology, other important technologies and methods commonly used in the photovoltaic industry include: photoluminescence (PL) and electroluminescence (EL) are two commonly used inspection methods.

PL imaging uses optical excitation (such as laser irradiation) to generate electron-hole pairs and emits through radiation recombination, which triggers the camera's photosensitive imaging. The band-to-band emission around 1,150 nm provides information about internal defects and dislocation clusters in silicon-based materials.

In addition, by plotting the luminescence spectrum of the defect band at approximately 1,550 nm, results regarding the ultimate cell efficiency limit can be obtained. Therefore, InGaAs cameras with high detection sensitivity in the 900 nm to 1,700 nm range are very suitable for such applications.

In addition to crystalline silicon, this technology can also be used to inspect other types of solar cells or module materials (also called thin-film solar cells): 700 nm to 1,330 nm (depending on the indium/gallium ratio) wavelength range inspection of copper indium diselenide Gallium (CIGS); 1,330 nm wavelength range inspection of copper indium diselenide (CIS).

Compared with CCD and CMOS cameras, the main advantages of short-wave infrared are shorter exposure time and excellent quantum efficiency (QE) in the silicon main emission wavelength range, thus ensuring rapid identification in the production process. The exposure time required for CCD or CMOS cameras is longer, up to 30 seconds. Even with the NIR-enhanced CCD sensor, the required exposure time can reach 3 seconds or more. The short-wave infrared camera only needs a few milliseconds, so it can greatly increase the production capacity.

The SWIR imaging camera designed and manufactured by JAVOL uses the latest advanced InGaAs sensor, based on 640 x 512, 15μm InGaAs sensor (0.9μm to 1.7μm), has the advantages of small size, lightweight, low power consumption, suitable for a wide range of machine vision application. Flexible installation and configuration, with excellent short-wave infrared imaging performance, easy to integrate with various optoelectronic systems. If you want to learn more about SWIR imaging cameras after reading the above, please contact us for a comprehensive solution.

With excellent production technology and thoughtful service, we have become one of the leading manufacturers of infrared thermal imaging systems. Our professional production team and complete management system can meet the diverse needs of customers. We will continue to adjust and optimize new solutions according to customer needs and can provide customers with thoughtful one-stop service. If you want to buy our SWIR camera, please contact us immediately!