Semiconductor Glossary

Optical Proximity Correction: A photolithography enhancement technique for offsetting the optical proximity effect, a phenomenon in which photomask patterns transferred onto a photoresist under insufficient resolution develop inaccuracies. OPC offsets those image errors by adding intricate modifications to the original photomask pattern, so the projected image on the photoresist accurately reflects the intended circuit pattern.

Optoelectronics: A coinage combining opto- (a prefix meaning light) and electronics. The word refers to technologies enabling conversion of electric signals into light and vice versa. Representative optoelectronic devices include optical fibers and LEDs.

P-Type Semiconductor (Positive Semiconductor): In p-type semiconductors, electron holes move when a voltage is applied, carrying positive charge to produce an electric current. P-type semiconductors are created by doping quadrivalent semiconductor materials (such as silicon) with trace amount of trivalent elements (such as boron).

Photolithography: A process of exposing a photomask pattern onto a photoresist-coated substrate to transfer the pattern using ultraviolet or visible light. Either a contact/proximity system or a projection system is used depending on the preferred exposure method.

Photomask: A plate used in a lithographic exposure system for transferring a circuit pattern onto a photoresist-coated wafer in the IC/LSI fabrication process. Typically, a photomask is a plate of fused quartz on which a circuit pattern is formed using chromium (Cr) or other opaque materials.

Photomask Equipment: A type of semiconductor manufacturing equipment used to fabricate photomasks by forming a pattern of integrated circuits on glass plates. Photomasks are similar in function to negative film. The mainstream mask-making technology has shifted from optical lens-based tools to electron beam lithography tools.

Photoresist: A light-sensitive resin coating used to transfer masked circuit patterns on a substrate by means of exposure and development. The type of photoresist in which the exposed portion is removed is called a positive photoresist, and one in which the exposed portion remains is called a negative photoresist.

Plasma Display: A type of flat panel display which, along with LCD, attracted a lot of attention as the next-generation display technology when it came out. A plasma display panel has numerous tiny cells encapsulating neon and other noble gases. When a voltage is applied, the gases in each cell light up and form images on the screen.

Printed Circuit Board (PCB): An insulated substrate on which an electronic circuit pattern is formed. Capacitors and other electronic components are soldered on the PCB to complete the circuit. Among its varieties are multi-layered PCBs and flexible PCBs.

Rambus Dynamic Random Access Memory: A type of DRAM developed by U.S.-based Rambus Incorporated featuring an ultra-fast interface. The device was originally touted to be the next-generation DRAM with a 500 MB/s bandwidth, which was five to ten times greater than conventional DRAMs. However, it failed to become the next industry standard due to stiff pricing, and was replaced by double data rate synchronous dynamic random-access memory (DDR SDRAM) devices. Today, Rambus DRAMs have very limited applications.