Canon EOS20Da
Zeiss 55mm Contax F/1.7 with 70mm of extension tubes.
The rays of the setting sun coming through a conservatory window were used to illuminate the chip
Camera mounted on a 4" long standard 1/2" optical post held in the 4 axis (tilt, tip, Y, Z) as shown below:
The chip was stuck to surface of a small aluminium block with double sided foam tape. This block in turn sat on top of a short length of HDPE rod which in turn sat on a 3 axis mount (X, Y, Z) as shown below:
The 2 positioners sat on a piece of 30mm x 300m x 600mm polished granite as shown below:
|
The lens aperture was set at F/2.8 (according to the engraved markings on the lens barrel). In reality the image space F/number was closer to F/6.3 and the object space F/No closer to F/5. Image magnification was about 1.27 (determined largely by the 70mm total length of the extension tubes)
Camera mode set to P (programmed automatic exposure) Since a Zeiss lens is used the camera cannot vary the aperture for the exposure, it can only vary the exposure time.
The lens was focused slightly beyond the chip surface and a sequence of exposures taken with the distance from the chip to the lens deceased by 0.001" (micrometer graduations on 3 axis stage) between successive exposures for a total of 74 exposures. The exposure which best showed the bond wire detail being selected.
1/400 sec.