CHIP | CHIP

Key Words: dielectric deposition, doping, epitaxy, etching, metallization, passivation, patterning, photolithography, semiconductor, thermal oxidation, Wafer

Definition:A chip is a miniature electronic circuit (from approximately 1mm - 10 mm square) manufactured on the surface of semiconductor material. Terms such as integrated circuit (IC), microcircuit, microchip, semiconductor chip, silicon chip are used interchangeably with the term 'chip'

TECHNOLOGY:

The manufacture of a chip is a multi-step process during which several identical copies (typically hundreds) of the chip are formed on a single wafer. Each step in the process contributes to building a multilayered, interconnected electronic circuit able to switch and transfer signals from one area of the chip to another. Some areas of the chip may incorporate insulating materials, while others may contain dopants that alter electrical properties. Fabrication of the chip may involve several often repeated steps that include thermal oxidation, patterning, etching, doping, dielectric deposition and metallization, passivation and testing. Following testing, the wafer is diamond cut into component 'dice' or 'dies' and assembled into a package that includes any necessary interconnecting wires for its final intended use. To avoid using wires to connect numbers of chips in a device, some manufacturers are now stacking chips vertically with connections traveling directly through the chips. This allows information between chips to be exchanged more efficiently and quickly. Microscopy is used throughout the fabrication process as a quality control tool to verify correct patterning and deposition and to detect any contamination (dust, oily form etc) that could interfere with chip function. The fabrication process is carried out under clean room conditions to protect chips from contaminants.

APPLICATIONS:

Chips are a fundamental to today's electronic technologies and are employed in, for example, military and aerospace applications, medical instruments, consumer goods, automotive products, and communications fields. Chip fabrication is central to applications such as lab-on-a-chip and nanotechnology devices, which may also incorporate micro-fluidic as well as electronic circuits.

IMAGE: Courtesy of Microscopy U

Caption: Surface of a chip captured in brightfield (a), darkfield (b), and DIC illumination using a vertical illuminator and reflected light (c). For more information go to MicroscopyU

MICROSCOPE CONFIGURATION:

A variety of microscope systems have been designed for wafer inspection and measurement using brightfield, darkfield, DIC, reflected light, fluorescence and confocal techniques. Manual handling and contamination must be avoided to prevent wafer damage. Inspection and measuring microscopes are usually accompanied by a wafer loader that robotically positions the wafer for examination.

RECOMMENDED SYSTEM:

Key equipment includes the Eclipse LV150 series modular reflected light microscope for 150mm wafer inspection, the Eclipse L200 series for 200mm wafers, and L300 series for 300mm wafers. These may be configured with NWL-641 and NWL-860 wafer loaders capable of handling 100-150 mm and 150 and 200mm wafers respectively.

The NEXIV VM-450C is designed for use with 300mm Front Opening Unified Pod (FOUP) & Front Opening Shipping Box (FOSB) wafer carriers. It detects hard to see edges using a variety of illumination features. By incorporating laser auto focus that provides quick non-contact focusing (even on transparent surfaces and on the edge of wafer peripheries) the VM-450C is able to measure semi-standard dimensions with accuracy.

LINKS:

Reflected light DIC microscopy: