AQL Advanced Quality Line (AQL). Fully-integrated production
line for mask blanks conforming to a very high
technological and quality standard.
CaF2 Calcium fluoride. Chemical composition of a (mono)
crystal that is used in optical lithography for light at
wavelengths of 157 nm, and in some cases 193 nm.
This material excels over other materials due to its high
transmission of these wavelengths, making it almost
unique in this respect.
Chip Integrated circuit on silicon.
Design rule Defines the size of structures that can be produced with a
certain technology. For example, chips produced with the
0.35 µm design rule have structures (conducting lines, or
dimensions of transistor components) with a width of
0.35 µm.
EUV Extreme Ultra-Violet (light): Ultra-violet light that is not
visible to the human eye and has an extremely short wave-
length. Visible light exhibits wavelengths of between
approx. 800 nm (red) and approx. 400 nm (blue),
Ultra-violet light has a wavelength smaller than 400 nm.
In lithography, EUV has a wavelength of approx 13 nm.
Excimer laser Lasers are artificial light sources whose light consists of only
one wavelength (“color”). Excimer lasers produce very high
energy (very intensive light) and are almost perfectly
monochromatic. Their wavelengths all reside within the deep
ultraviolet range and are used in lithography to produce chips
in large volumes and at high throughput rates. Excimer laser
light is generated by a mixture of gases, e.g. argon and
fluoride, in a chamber that is ”ignited” with an electrical
discharge.
Fused silica Glass made of quartz.
IC Integrated Circuit: Electronic circuit integrated on a
semiconductor.
i-line glass Special glass for optical components used in lithography,
with a transmission wavelength of 365 nm. The term derives
from a particular colour in the light spectrum of halogen
lamps.
Mask See Photomask.
Mask Blank Glass plate with a chromium and a photoresist coating. Mask
blanks are used as raw materials for producing a mask.
Lithography Generic term referring to the technology for producing ICs.
Micro = 1 millionth of a meter, lithography = “printing
technique”, “stone printing”.
Monocrystals Materials with homogenous properties throughout their entire
volume. Ceramics and polycrystals are comprised of many
monocrystals that are separated from each other by grain
boundaries.
Moore’s Law Empirical law according to which, inter alia, the density
of transistors per square centimeter increases. The law is
named after its discoverer.
OPC Optical Proximity Correction: A special method for copying
even the smallest of structures, sharply and design rule-
compliant, from a mask to a chip. This technology makes
it possible to generate structures with dimensions less than the
wavelength of the light used to illuminate the wafer. According
to classical optics, this would be impossible.
Photolithography See also: Lithography. Photolithography is lithography
performed with light. Lithography, by contrast, is much
slower and is performed with electron beams.
Photomasks Also: Masks. The layouts of conducting lines, transistor
components and many other structures comprising an
integrated circuit are reproduced on photomasks.
An average of 25 photomasks are required to produce
an IC.
Photoresist Also: Resist. A light-sensitive coating (similar to the
light-sensitive layer on a camera film).
Projector lenses Lenses used to sharply project the image on an illuminated
photomask onto the wafer, akin to projecting a slide photo
onto a screen using a slide projector. Unlike a slide projector,
however, the “picture” on the photomask is reduced in size in
lithography.
PSM Phase Shift Masks. With the help of these special photomasks,
structures can be reproduced, in a manner similar to OPC, that
are smaller in dimension that the smallest “normal” structures.
OPC and PSM help chip manufacturers to use existing steppers
and scanners for design rules lower in dimension that the
design rule for which they were designed.
Reticle Mask used in scanners. See also: photomask.
Road Map Plan adopted by companies in the semiconductor industry that
defines future developments in lithography with regard to
sequence, design rule and the ensuing product specifications for
steppers, scanners, photomasks, etc., etc.
Scanner Device for illuminating wafers coated with photoresist material.
Unlike steppers, scanners scan the entire mask with a beam of
light.
Stepper Device for illuminating wafers coated with photoresist material.
Unlike scanners, steppers illuminate part of the wafer in one
step, then move the wafer and/or the photomask and repeat
the procedure.
Substrate Planar parallel plates of glass with a highly polished surface.
These serve as raw material for making mask blanks. They
are coated with a chromium and then a photoresist layer.
Wafers Circular disks of material. In semiconductor production:
raw silicon material for producing ICs.
Wavelength Physical description of the “color” of light.
ZERODUR® Registered trademark held by SCHOTT Company.
ZERODUR® is a zeroexpansion material.
See entry above.
Zero-expansion A material that does not expand in size when
material temperature increases.
