Semiconductor Glossary

Design In: An approach to semiconductor product development that involves early cooperation between a manufacturer and its marketers and users to ensure the designs are optimal for practical use. Even more radical approaches are emerging lately, including “concept in” and “research in,” which call for third party involvement at the product planning stage or earlier.

Diode: A diode originally referred to a vacuum tube with two electrodes, but today it refers to a two-terminal electronic device, typically made of a semiconductor with a p-n junction. Diodes are used in many electronic devices as rectifiers. They are also representative discrete semiconductors.

Dual Inline Package: A type of IC package with a rectangular housing and two parallel rows of electrical connecting pins, giving it a centipede-like appearance. It was the most common package type in the early days of ICs.

Discrete: An adjective used to describe types of semiconductor devices that perform a single function, such as transistors and diodes as opposed to integrated circuits. It is also used to describe digital electric signals, because digital signals are sampled and quantized, meaning that they are not continuous either on the time or amplitude axis.

Dynamic Random Access Memory: A type of semiconductor memory used in the main storage unit of a computer or as large-capacity working memory of other electronic devices. It is the most common type of memory that allows data to be read or written instantly as needed. A DRAM stores each bit of data in a cell consisting of a pair of a MOS transistor and a capacitor. When a bit of data is stored, the capacitor in the cell changes its state to either charged or discharged, representing the value 0 or 1 in the binary numeral system. To prevent the capacitor charge from fading through data reading and natural leakage, DRAM needs periodical refreshing.

Digital Signal Processor: A microprocessor capable of performing large numbers of multiplications at high speeds for quantization and other processes used in digitizing image and sound signals. A DSP typically has a high-speed data bus and a multiplier. Many advanced microprocessors today serve similar functions, however, making the conventional definition of DSP less pertinent.

Electronic Design Automation: A computer-assisted process for automatically designing semiconductors and electronic circuits. Also refers to dedicated tools (hardware and software) designed to serve this purpose. EDA covers the entire segments to be designed, including specifications, functions, logic, circuits, and layout.

Electron Beam: An electron beam is a stream of electrons, which are typically induced thermally from a cathode and flow to an anode. In electron beam processing, the flow of electrons is accelerated by electric fields, and as it strikes the target the material is drilled or welded as appropriate.

Eleven Nines: Eleven nines means 99.999999999%. When used in reference to a material, it means having a purity of 99.999999999%. Production of semiconductor devices such as ICs requires materials that are “eleven nines” pure. Silicon, a representative semiconducting material, becomes nearly nonconductive at this level of purity.

Embedded Array: A variation of ASIC that combines the advantages of a gate array and a standard cell. An embedded array is basically a gate array embedded with some high value-added cells.

Epitaxial Growth: Epitaxial growth, or epitaxy, refers to the deposition of a crystalline overlayer (epitaxial layer) on a crystalline substrate. The crystal orientation of the epitaxial layer depends on the structure of the substrate and seed crystals. Epitaxy is used for manufacturing Si ingots and for depositing suitable crystal layers on the wafer surface.

Electron Projection Lithography: A technology for scaling down and transferring the mask pattern onto the wafer surface by means of electron beams. ELP enables high resolutions and deep DOF (depth of focus), and is suitable for transferring resist mask patterns to form contact holes with a high aspect ratio.

Erasable Programmable Read Only Memory: A type of semiconductor memory chip on which data can be written and erased a certain number of times. An EPROM is basically a read-only memory that can be reprogrammed. The data can be typically erased by exposing the chip to intense ultraviolet light through a transparent opening on the package. In addition to this type of EPROM (referred to as UVEPROM), the Electrically Erasable Programmable Read-Only Memory (EEPROM) was also developed to provide an electrical erase function. Both types of EPROM were used widely, but have been replaced by flash memory in recent years.

Esaki Diode (Tunnel Diode): A type of semiconductor that uses the quantum tunneling effect. It was invented by Leona (Leo) Esaki in 1957. When a forward-biased current flows through this diode and the voltage is gradually increased, negative resistance is produced at a certain voltage range, meaning the current decreases as the voltage gets higher. In fact, oscillators and amplifiers equipped with Esaki diodes delivered far superior performance than those with conventional diodes.

Etching: A process of chemically removing from wafer surface part of the layers that is not covered by the patterned resist. There are two types of etching: liquid-based “wet” etching and plasma-based “dry” etching.

Etching Equipment: A type of machinery used for etching the surface of semiconductor wafers to form set patterns of metal interconnects, lead frames, printed circuit boards, etc. Also called an etcher. The terms etching equipment and etcher typically refer to plasma-based dry etching systems.

Extreme Ultraviolet Lithography: A lithography technology using the 13.5 nm extreme ultraviolet wavelength along with reflective masks and mirrors. EUV is capable of delivering the highest pattern resolutions among all optical lithography technologies. Because the light’s intensity is diminished at each reflection, however, a high-powered EUV light source is needed to raise productivity, a problem that still needs to be addressed.