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Delvotec Pegasus 3600
Die bonding
The die bonder is used to dispense adhesive in a pre-chosen pattern before the die is placed on the substrate. The adhesive is then cured in an oven.
The die bonder also has flip chip capabilities. Flip chip provides high packaging density and performance and a low packaging profile. Flip chip technology is defined as mounting the chip, with the active side facing down, on a substrate with any kind of interconnect material. In most, if not all, flip chip systems in production today the chip is bumped, i.e., on each contact pad on the chip there is a quasi-spherical bump. The bump array pattern is mirrored onto the substrate chip site. The bumps are usually metal and serve as the joint forming material, either together with solder or adhesive or through melting the bump itself.
The advantages of flip chip technology are the short interconnects for improved electrical performance and reduction of size and weight which results in cost savings since less silicon and circuit board material are used. The total size can be reduced in three dimensions because the naked chip takes less space both in height and in width compared to the packaged chip. Each chip can have many connections since it is possible to have contact points on the whole surface area instead of just at the periphery. In optoelectronics the requirements on alignment accuracy are often very extreme. Flip chip offers the benefit of self-alignment through the soldering process. Ballbonder: Delvotec bonder 5610
A gold or aluminium wire is bonded between each pad on the chip and the corresponding bonding surface on the carrier. After chip mounting and bonding the chip and its wires are protected from mechanical and chemical impact by a local epoxy encapsulation called glob top or dam and fill. For additional protection the entire module can be encapsulated, a method used when the electronics will be exposed to harsh environments. Today, about 95% of all chips are wire bonded, either inside a package or directly to a substrate.
The equipment has the option of making stud bumps for flip chip assembly. Bumping flip chips can be achieved in many different ways. Today the availability of bumped dies is considered to be a significant bottleneck for flip chip production. One method of bumping is to use a ball bonder to make stud bumps. A ball bonder is used to form a ball on the aluminium pad. The wire is then pulled to breakage. The high speed of today’s wire bonders makes ball bonding an attractive alternative to plating. This method is especially suitable for prototyping.
Deep access wedge-wedge bonder
Delvotec bonder 5632
The deep access bonding head makes it possible to reach down in very narrow cavities. The machine uses both gold and aluminium wires. Pulltester 5600
A pulltester is used to verify the bonding parameters. |