Machine Design

Vision system takes a fast look at fluid dispensers

Speedy machine-vision processing lets fluid-dispense heads find their targets on printed-circuit boards.

In underfill operations handled by Asymtek dispensing platforms, a bead of encapsulating epoxy resin is dispensed near the chip and draws by capillary action into the space between the chip and the carrier. The epoxy resin underfill mechanically couples the chip and the carrier and minimizes the temperature coefficient mismatch between them. Coreco imaging is a standard feature on Asymtek Century systems (above) as well as Millennium and Axiom 1010 dispensing platforms.

The automated fluid-dispensing systems fielded by the Asymtek subsidiary of Nordson Corp., Carlsbad, Calif., often have a role in underfilling semiconductor ICs to pull away heat, and in encapsulating chips to augment structural integrity and corrosion resistance.

Machinevision systems from Dalsa Coreco, Quebec, make this operation possible by giving the motioncontrol system coordinates for positioning the dispense head. The Coreco gear also helps inspect the chips once the fluid is in place.

Key components in the machine-vision system are PCVision frame grabbers/ image processors, highspeed CCD cameras, and software that corrects any misalignment in the workpiece. The PCVision frame grabber is specially designed for high-end machine-vision use. It drives the camera directlyto eliminate any possible jitter that can otherwise arise in the more traditional method of phase-lock-loop syncing the frame grabber with the camera.

A PC built into the Asymtek equipment coordinates the machinevision components. The Coreco vision engine takes a series of measurements to find the chip die edges and then calculates the corner coordinates. The Coreco system works with Asymtek patternrecognition software to hustle image acquisition and processing, thus boosting machine throughput.

(800) 279-6835,
Dalsa Coreco, (978) 670-2000,

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