Manufacturing lines include inspection systems for monitoring the quality of parts produced. Manufacturing lines for making
semiconductor devices generally inspect each fabricated part. The information obtained is used to fix manufacturing problems in the
semiconductor fab
plant. A
machine-vision
system for inspecting devices includes a
light source for propagating light to the device and an
image detector that receives light from the device. Also included is a light sensor
assembly for receiving a portion of the light from the
light source. The light sensor
assembly produces an output
signal responsive to the intensity of the light received at the light sensor
assembly. A controller controls the amount of light received by the
image detector to a desired intensity range in response to the output from the light sensor. The
image detector may include an array of imaging pixels. The imaging
system may also include a memory device which stores correction values for at least one of the pixels in the array of imaging pixels. To minimize or control thermal drift of signals output from an array of imaging pixels, the
machine-vision
system may also include a cooling element attached to the imaging device. The
light source for propagating light to the device may be strobed. The image
detector that receives light from the device remains in a
fixed position with respect to the strobed light source. A translation element moves the strobed light source and image
detector with respect to the device. The strobed light may be alternated between a first and second level.