Browse Prior Art Database

Optical Profiler

IP.com Disclosure Number: IPCOM000078656D
Original Publication Date: 1973-Feb-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Ionta, AM: AUTHOR [+4]

Abstract

This optical profiler allows the automatic quantitative measurement of small physical dimensions in a dynamic mode, such as required in detecting and profiling solder pad terminals on integrated circuit chips, variations of which may produce reliability problems.

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Optical Profiler

This optical profiler allows the automatic quantitative measurement of small physical dimensions in a dynamic mode, such as required in detecting and profiling solder pad terminals on integrated circuit chips, variations of which may produce reliability problems.

The profiler includes, as shown in Fig. 1, a detector comprising an opaque plate 1 including a very narrow slit 2, or aperture, on the order of less than a mil in width. Mounted in close proximity, and preferably as close as possible to plate 1 is a sensitive photocell 3. Spacing is maintained at a minimum to reduce diffraction effects. A light source, not shown, is positioned opposite the detector. By passing an object to be inspected close to the detector at a uniform rate between the light source and the detector, a shadow representing the profile of the object will be cast on the detector and sampled by slit 2. Fig. 2 shows, for example, a portion of an integrated circuit chip 4 having mounted thereon a solder pad 5 typically about 8 mils wide and 5 mils high, being passed in front of the detector.

Fig. 3 represents the output of photocell 3 on a time scale. The output 6 represents the actual analog profile of the object measured. For the object shown, distances, such as d, representing the position of a solder pad with respect to the edge 7 of a substrate may be monitored, also, diameter D, and height, h, may be monitored to a high degree of accuracy with respect to the self- contai...