Opto Relay & Chip Switch Assembly
The assembly process combines two different wire bonding techniques in just one single product. A LED is wired into the circuit with 1.0 mil gold wire using a thermosonic ball bonder,while the FET’s are wire bonded with an Orthodyne heavy aluminum wedge bonder. Sizes of aluminum wires used range from 2.0 mils up to 6.0 mils.
There are several unique features in the assembly of this product line. Leadframes are custom design according to the product application. Some products require alumina substrates attached into the leadframe. Hexfet devices are coupled to a LED by means of a sub-process called dome coating using a clear, transparent silicone material. White epoxy molding compound is used as encapsulant.
Dome coating is considered as the most delicate part of the process. Strict criteria are observed in terms of the height and shape of the dome. Dispensing of silicone material is tightly controlled to ensure just the right amount to cover all bond wires but without getting in contact with certain portions of the leadframe.
The final product comes in three different options: dual in line insertion, single in line, or surface mount. Final electrical test is performed with every device having a unique test program of its own