Semiconductor processing equipment manufacturers are striving to achieve several goals. Their equipment must deal with shrinking feature sizes, requiring an increasing level of precision in the positioning ability of the machinery. At the same time, higher throughput is demanded of the system. This necessitates faster mechanisms, which tends to oppose the goal of superior precision. They must also compete in a global marketplace, which requires they keep the costs as low as possible, while making faster, more precise mechanisms.

BEI Kimco utilizes Integrated's magnetic field simulation software for the design and optimization of their voice coil actuators. "Integrated's magnetic simulation software has been key design tools in helping us further optimize the performance, speed and precision of our positioning actuators", said Mike Godkin, Director of Engineering for BEI Kimco. "By implementing Integrated's software we've been able to dramatically minimize the number of design iterations for our linear actuators. This allows us to provide a solution that meets our customers' expectations like Kulicke & Soffa's... the first time."

BEI Kimco was able to leverage its strength in magnet voice coil actuators to enable the latest generation of automated wire bonders from Kulicke & Soffa. These wire bonders make the necessary connections between the internal die of an integrated circuit and the outside leads that exit the chip package. Current processor chips can take high tens of connections per device. This makes bonding speed very important for volume production. Placement, accuracy and reliability are also absolutely important to help achieve the desired yield and reliability for the devices being manufactured. Kulicke & Soffa needed both the fastest and most precise mechanism to achieve new levels of bonding performance. "Integrated's design tools enable us to build in this sort of speed and precision to the critical magnetic circuit of the actuator", added Mike Godkin.

Linear voice coil actuators were the ideal approach to achieve the necessary goals. For stroke lengths of a few inches with loads in the tens of pounds, linear voice coil actuators offer the right combination of blinding speed with controllability. They have no preferred position or cogging, which might inhibit or slow positioning to certain areas. Using high-energy magnets allows voice coil actuators to achieve acceleration rates up to 100s of Gs.

For the wire bonder design, the manufacturer utilized three voice coil actuators. Two relatively large open-frame linear actuators are used for the XY stage. This stage moves the piece to be bonded in the X and Y planes. A third actuator is used for the bonding head's Z-axis. All three axes utilize optical encoders for precise measurement of axis position. The new configuration of bonder with actuator/encoder mechanisms is able to raise bonding speed to 22 single bonds per second.

Optical encoders have been utilized in previous generations of bonders and are also in the latest ones. BEI encoders are used by wire bonding equipment for their accuracy, reliability, high data rates and ability to interface easily with mechanical equipment.

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