Advanced line speeds through flip-chip assembly

Universal Instruments has designed an advanced assembly line that can assemble over 2000 flip chips per hour on flexible circuits.

Universal Instruments has designed an advanced assembly line that can assemble over 2000 flip chips per hour on flexible circuits.

The substrate is a thin flexible circuit that is normally processed in a carrier with eight to 12 circuits.

Each comprises a 3 to 5mm square pre-amplifier chip, five to ten discretes and a connector.

An optimised line consists of a screen printer to apply solder paste to the modules, a high speed chipshooter to pick and place the chip capacitors and the connector, a flip chip placement machine with integrated dip fluxing, and a reflow oven.

For some applications featuring high capacitor counts, two chipshooters would be required to optimise tact time.

Universal Instruments' chip placement platform configurations incorporate the company's proprietary, patented variable reluctance motor (VRM) linear motors, featuring dual drives and 1um linear encoders.

This provides an unbeatable combination of high accuracy and high speed, and enables the machines to be used in clean room environments.

VRM technology is also at the heart of Universal's 30-spindle rotary Lightning head - a dynamic chip placement solution that is considerably smaller than equivalent mechanical turret heads typically deployed to place small discrete components.

In addition, a four-spindle pressure enhanced (PE) head is used to place challenging components that demand higher accuracy.

The PE head is used in conjunction with Universal's Magellan camera - a high resolution digital upward looking camera (ULC).

For the equipment designers, a major technical barrier was accurately imaging the component.

The development project successfully identified a need for a lighting module that integrates both blue and red LEDs to handle the wide spectrum of materials, such as polyimide, copper etc.

The team also redesigned the dip fluxing unit to be able to gang dip several components concurrently by adopting a linear rather than rotary mechanism.

This unit is the largest of its kind in our industry.

The optimal tact time for the line is between 20 and 25 seconds.

A twin-beam Universal Instruments GSM Genesis platform equipped with two Lightning heads handles the discretes and the connectors.

A second platform machine featuring a linear motor positioning system and a four spindle head combined with the Magellan ULC places all the flip chips to an accuracy of +/-9um at +/-3 sigma.

Both machines are certified UL, CE, SEMI S2 and SEMI S8.

Back to top