Glossary

Aberration

Deviation of the light from the ideal path in an optical system. Aberrations are classified into six elements: Seidel's five aberrations (coma, spherical aberration, curvature, astigmatism, distortion) and chromatic aberration.

ADC

Automatic Defect Classification
A function that an inspection machine automatically classifies defects.

Aerial Image

Pattern image of a photomask projected onto a wafer where resist is to be placed.
Developed resist is not always formed like the pattern of the aerial image.

AFM

Atomic force microscope. AFM is used for measuring fine surface irregularity by using atomic force generated between a very fine needle tip and sample surface,

Air Mass (A.M.)

The spectrum of sunlight is indicated by Air Mass and the sunlight spectra (Spectral Intensity) in outer space is defined to be AM0 and the Air Mass of sunlight perpendicularly incident into the earth is defined to be AM1. Although Air Mass value varies with season, time of the day and latitude, AM1.5 is usually used as a standard for evaluating Solar cells.

Aligner

A photolithography tool that transfers the patterns of a photomask onto a resist-coated wafer on which an electronic circuit is to be formed.
This tool utilizes a UV lamp for the exposure and typically the pattern size of the photomask is equal to the pattern to be formed on wafer.

Alt-PSM

Alternating Phase Shift Mask
One type of phase shift mask.
Levenson type phase shift Masks (all the phase shift mask other than the Half Tone type phase shift mask).

Amorphous Silicon Thin Film Solar Cell

A Solar cell made of amorphous silicon thin film: Because amorphous silicon shows high optical absorption coefficient and is easy to be formed, it is possible to fabricate a Solar cell with thin film over a glass substrate. Large size Solar cell is producible at a low cost but efficiency is low compared with that of crystal type Solar cell.

Annealing

To expose wafers into high temperature non-oxidizing gas in order to stabilize interface character

AOD

Acoustic Optical Deflector
A device that deflects laser light by diffraction at ultrasonic wave front generated at the surface of the optical medium. Because of no mechanical moving part in this device, it enables a very high speed scanning of the light.

APC

Advanced Process Control
A kind of lithographic process control which utilizes feedback and/or feedforward of the process.

ArF

Argon Fluoride
ArF excimer laser used as an exposure light source
Laser wavelength: 193nm

Artificial Sunlight

Artificial sunlight is made of a lamp such as a Xenon lamp combined with suitable filters. Solar cell is normally measured by an artificial sunlight at the output intensity of 100 mW/cm2 with A.M. 1.5 spectrum.

A Solar Module

A structure consisting of a number of Solar Cells

Att-PSM

Attenuated Phase Shift Mask
One type of phase shift mask.
It is also called Half Tone type phase shift mask.