An integrated circuit package has the sole purpose of protecting and maintaining one or more integrated circuits. It is usually in the form of a plastic, glass, metal, or ceramic casing which creates a physical barrier of protection against things like impact and corrosion. Furthermore, it helps to hold contact pins or leads which are used to connect the device from external circuits, and it helps to drive away heat from the actual device. These packages or protection units consist out of a number of individual parts that are all very important to the overall functioning of this integrated circuit.
The leads are usually made out of copper with a thin plating of tin with finer wires connected to the package. These are used to create a strong connection between the leads and the integrated circuit. Leads are then bonded with conductive pads on the semiconductor die. On the outside of the package, the leads are then connected to the printed circuit board by means of soldering (oven-reflow soldering).
Earlier integrated circuits made frequent use of sockets which provided better reliability when they were soldered onto the printed circuit boards. It helped to give the package a better immunity against heating and higher temperatures. Today, sockets are not as frequently used, but they still play an important part when it comes to the experimenting and testing of integrated circuit. It is used as a cheaper option where replacement is better than discarding the product, or for application where the chip contains firmware or unique data. Devices that are equipped with hundreds of leads may be accompanied by zero insertion force sockets as well.
As already stated, the package material can consist out of a number of different materials. The most common material that is used is any sort of epoxy plastic which can provide adequate protection according to the size of the device and it has the strength to support the leads or handling of the package. In environments where the packaging will be used for aerospace purposes or in radiation cases, a ceramic material is used. Other materials can include metal types which works great for conducting heat and an easy assembly. These are usually preferred when working with high power wattage.
Integrated circuit package makes it possible for designers to create hybrid versions of their products. During these processes multiple types of semiconductor dies and components are assembled into a single substrate. The substrate is then connected to an external circuit and is then enveloped in a welded or frit cover. This method is often more expensive than conventional design methods, but it can offer the best cost-size benefits of integrated circuits.
