Front-end and Back-end Test

Semiconductor Production Process: Front-end and Back-end

The semiconductor production process can be divided into two sequential sub-processes commonly referred to as front-end and back-end production, both of which contain many steps. The entire process, both front-end and back-end production, is complex and requires sophisticated engineering and manufacturing expertise. The diagram below summarizes the process.

Front-end production

Wafer Fabrication. Front-end production refers primarily to wafer fabrication. It starts with a clean disc-shaped silicon wafer that will ultimately become many silicon chips. First, a photomask that defines the circuit patterns for the transistors and interconnect layers is created. This mask is then laid on the clean silicon wafer and is used to map the circuit design. Transistors and other circuit elements are then formed on the wafer through photolithography. Photolithography involves a series of steps in which a photosensitive material is deposited on the wafer and exposed to light through a patterned mask; unwanted exposed material is then etched away, leaving only the desired circuit pattern on the wafer. By stacking the various patterns, individual elements of the semiconductor chip are defined. During the final phase of the front-end production process, each individual chip on the wafer is electrically tested to identify properly functioning chips for assembly.

Back-end production

Assembly and Test. Back-end production refers to the assembly and test of individual semiconductors. The assembly process is necessary to protect the chip, facilitate its integration into electronic systems, limit electrical interference and enable the dissipation of heat from the device. Once the front-end production process is complete, the wafer is transferred to an assembly facility, where it is sawed into individual semiconductor chips. These semiconductor chips are then individually attached by means of an alloy or an adhesive to a lead frame, a metallic device used to connect the semiconductor to a circuit board. Leads on the lead frame are then connected by aluminium or gold wires to the input/output terminals on the semiconductor chip through the use of automated machines known as wire bonders. Each semiconductor device is then encapsulated in a plastic molding compound or ceramic case, forming the package.

After assembly, power semiconductors are tested for different operating specifications, including functionality, voltage, current and timing. The completed packages are then shipped to the customer or to their final end-user destination through drop shipment.

Research by : Wan Aiman