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1X reticle
The reticle is the medium by which a stepper can transfer a chip
design from an engineer's computerized layout to the wafer. Ultratech
wafer steppers manufactured at the San Jose facility use a Wynne-Dyson
lens design and 1X reticle technology.
Annealing
A baking process typically used to incorporate doping atoms into
the silicon crystal lattice.
ASIC
Application-specific integrated circuit.
Aspect ratio
The width-to-height ratio of patterned features on a substrate.
Bump processing
A method of placing "bumps," typically solder or other conducting
material, onto IC bond pads so that the IC is mounted to either
a package or a printed circuit board directly.
Cost of ownership
The total cost a manufacturer incurs to "own" a piece of capital
equipment throughout that equipment's lifetime, including initial
costs and yearly operating costs.
Doping
The deliberate introduction of specific impurity atoms into the
silicon crystal lattice to change its electrical properties.
DRAM
Dynamic random-access memory.
gh-line
Exposure wavelength of 436 nanometers.
GILA (Gas Immersion Laser Annealing)
A self-aligned silicide (SALICIDE) process for forming low resistance
contacts at sub-critical dimension spacing as part of high-performance
CMOS logic fabrication.
i-line
Exposure wavelength of 365 nanometers.
Inductive thin film head
An electromechanical device that records (writes) data on and retrieves
(reads) data from the magnetic recording layer of the disk inside
the disk drive. Inductive heads read and write data using a conductive
coil wrapped around a very small stylus.
Magneto-resistive (MR) head
Recording head that uses an inductive thin film element to write
data onto the media and a separate MR element to read the data.
The use of a separate but much more sensitive read element permits
data to be recorded and, subsequently, read at much higher track
densities than inductive thin film head technology.
MEMS (Microelectromechanical systems)
A term often used interchangeably with micromachining.
Micromachining
The application of integrated circuit fabrication processes to the
manufacture of miniature machines, sensors and switches.
Micron
One millionth of a meter.
Minimum feature size
The smallest dimensions imaged on the wafer's surface.
Mix-and-match
The cost-effective strategy by which manufacturers use expensive
reduction steppers for the critical layers of an integrated circuit
and cost-effective 1X steppers for layers larger than 0.65 microns.
MVS (Machine Vision System)
A pattern recognition alignment system that eliminates the need
for large scribe lines to support dedicated alignment targets.
P-GILD
Projection-Gas Immersion Laser Doping. This process merges photolithography,
doping and annealing.
Photolithography
Photography is the best analogy to describe the photolithography
process. The stepper is like a photographic enlarger where a light
source projects an image through a lens system onto photographic
paper. The machine used to do all of this is called a "stepper"
because it literally does one die or a few die at a time, then steps
to the next die or set of die until it has exposed the entire wafer.
Photomask
Also known as a "reticle" or "mask," this glass plate contains the
patterns used for photolithographic manufacture of integrated circuits.
Photoresist
A photoactive film also known as "resist." Liquid photoresist is
applied to a wafer to create a thin, uniform film. This film reacts
with light energy from the stepper to define a circuit or component
pattern on the substrate.
Photosensitive polyimide
A stress buffer overcoat used in the manufacture of devices designated
for advanced packaging applications. The photosensitive properties
of the material enable manufacturers to achieve in only four steps
what would otherwise require nine steps for nonphotosensitive polyimide.
Primary Lithography
A lithography market including the manufacture of low cost IC's,
consumer products, micromachining devices and various semiconductor
processes with minimum line-width requirements ³ 0.65 micron.
This market also includes scanner replacement for capacity expansion,
wafer size upgrades and new process integration.
Reduction stepper
Steppers that reduce the image contained on the reticle nX times,
usually 5X, but sometimes 4X, 2.5X or 2X, before exposing the wafer.
Refractive lens
A lens (composed of glass lens components) that bends or deflects
the path of light as it passes between different media, for example,
air or gas.
Scanner
Scanners are lithography tools that were first introduced in the
early 1970s to replace contact printers. Today, scanners are being
replaced by higher-technology steppers.
Semiconductor
An electronic device (also referred to as an integrated circuit
or IC), such as memory or a microcontroller, used in a variety of
applications including computer, automotive and telecommunications
products.
Stepper
A photolithography tool used in the production of semiconductor
devices, thin film recording heads, micromachined devices and so
forth. Also referred to as a step-and-repeat projection aligner,
stepper works by transferring the image of a circuit or component
from a master photomask image onto a small portion of the wafer
surface. The substrate is then moved or stepped, and the image is
exposed once again onto another area of the wafer. This process
is repeated until the entire wafer surface is exposed.
Substrate
See wafer.
Thin film head
Currently, the most advanced type of magnetic recording head used
to read and write information on disk drives. The two types of TFHs
are inductive and the more advanced magneto-resistive.
Wafer
1. Semiconductor wafers are made of round, thin slices of single-crystal
silicon and form the base substrate for semiconductor processing.
Wafer plane irradiance
Exposure light at the substrate surface.
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