Focal Plane Array / IR Sensor Bonding

Author: Sascha Lohse

Abstract: A Focal Plane Array (FPA) is a sensor with a a two-dimensional detector pixel matrix, i.e. for infra-red light or X-rays, positioned in the focal plane of an optical system.

Typically, FPA can be found in thermal cameras, astronomical instruments, inspection systems, medical imaging devices, bolometers, weapon guidance systems and other kinds of measuring units used to visualize phenomenons in various spectral ranges of electromagnetic waves.

For the most part, sensors designed as FPA are rather large and - as opposed to other types of sensors - feature a number of small, independent detector zones.  In order to work properly, a pixel-perfect connection to a readout unit (one or several read-out chips (ROCs) or ASICs) must be established. High pixel/bump counts and densities, tiny bump sizes and usually extremely small pitch make this a real challenge and have to be considered when choosing the best suitable bonding equipment and technology.