3D laser inspection system for bump inspection

Citation

(2000), "3D laser inspection system for bump inspection", Microelectronics International, Vol. 17 No. 2. https://doi.org/10.1108/mi.2000.21817bad.002

3D laser inspection system for bump inspection

Keywords Datacon, Electronic packaging, Inspection, Solder bumps

The market for advanced packaging - including advanced packaging applications such as flip-chips - will experience rapid growth in the years ahead. Ramping up production to meet this demand also involves more highly automated process management and quality assurance in the production of bumped wafers.

Datacon's new 8000is 3D inspection system, with its high accuracy and reliability combined with very high throughput, is ideal for this type of automated application. The 8000is analyzes the three-dimensional images used in bump, wire, wafer and postbonding inspection and can also be used to inspect the quality of bonding and soldering pastes. It represents a new era in quality assurance.

The eye of the 8000is is a specially developed 3D laser scanner head incorporated in an X/Y positioning system. The very high flexibility of the system is the result of designing all configurable components as exchangeable modules.

The 8000is 3D inspection system can be used to inspect 4- to 12-inch wafers (300 mm) as well as substrates and lead frames. The system operates unbuffered with its operation synchronized with the production process. It is capable of 100 per cent monitoring of all critical parameters, such as bump height and diameter, coplanarity, form and missing or incorrectly applied bumps.

Shadow effects are negligible with the 8000is 3D inspection system, because light path and detector are coaxial. A second important point is that only reflected light is used to measure bump height. Stray light from neighboring areas, that falsifies height data in conventional systems (triangulation), does not impair the signal quality in this system.

The scanning head works according to the confocal principle

The laser beam is projected through a lens onto the surface of the object to be analyzed. The light reflected from the test piece is mapped by the same lens through a semitransparent mirror onto a shadow mask. If the plane of the object is in focus, the signal reaching the detector behind the shadow mask is at its maximum. As soon as the test piece surface moves out of focus, the intensity of the signal received by the detector is reduced.

For further information contact Monika Walcher, Datacon Semiconductor Equipment GmbH, InnStr. 16, A-6240 Radfeld, Austria. Tel: +43-5337-600-104; Fax: +43-5337-600-695; E-mail: monika.waicher@datacon.at