New VP3 module from Viscom guarantees fast and reliable in-line 3-D paste inspection

At SMT 2007 in Nuremberg, Germany Viscom presented the new VP3 module for 3-D paste inspection to the public for the first time. In addition to the proven 2-D evaluation of completeness, displacement and smearing, now the volume of paste deposits for critical components such as BGAs or FlipChips can be reliably inspected. The print process itself is optimized, because systematic as well as sporadic defects are positively recognized.

Now a Viscom paste inspection system, with 100% 3-D inspection coverage at line speed, is available. With it, Viscom extends its product portfolio through the previously available solutions for 2-D and selective 3-D inspection, to a 3-D full surface inspection. Only a 3-D inspection can recognize if the correct solder paste volume is present and has been applied in the proper shape and position. Viscom accomplishes this with the VP3 module, which functions by isotropic polychromatic fringe projection: Special light patterns are simultaneously projected onto the PCB from three directions. Specific color coding of the light pattern allows multiple image capture simultaneously, and therefore provides high throughput with very high accuracy. Furthermore, radiating light from three directions ensures that the measurement is not dependent on the particular orientation of the inspection object. And, because its sensor head has no mechanical moving parts, the VP3 is extremely robust. This makes the 3-D paste inspection from Viscom especially well-suited for demanding production conditions.

This new, modular 3-D sensor concept achieves height resolution of <1 µm, which is particularly advantageous when critical print structures needed for components such as BGAs, Finch pitch etc. are inspected. In addition to the defect features: missing paste, smearing and short circuits, the height of the printed paste, its volume and also its topography can be measured and evaluated.

The 3-D option fits seamlessly into the existing Viscom AOI system range and is integrated into the Viscom S3088 system. The 3-D paste inspection is completely compatible with the existing software tools and add-on modules HARAN, off-line programming and EasyPro. This applies as well to the Viscom VPC, which in addition to straightforward good/bad verification also delivers SPC data about developing trends that affect production quality.