Spectral Lamps
Excerpts from a brochure about HBOs for microlithography by OSRAM*:
"Mercury short arc lamps (aka HBO) are direct-current short-arc gas discharge
lamps, in which the electric arc of the discharge takes place in a high-pressure
mercury atmosphere. They are [now] used primarily as a light source
in the manufacture of microchips, Liquid Crystal Displays (LCDs) and Printed
Circuit Boards (PCBs) (microlithography).
...[They were] used for ultraviolet light pens primarily at the beginning,
more and more new applications like fluorescent microscopy were added in
the years to follow. Apart from the use as a light source for UV-curing (photo
polymerization), the high power lamps have been used increasingly in the
production of semiconductor structures since the 1980s. At the beginning,
lamps with a power consumption of 200 W and 350 W were used whereby, depending
on the application, either a large share of the emission spectrum or selected
lines were employed for the exposure. With the increasing miniaturization
of the structures, lamps up to a power consumption of 1,000 W...
"...a spectrum is produced which consists primarily of the widened lines
of the mercury (depending on the pressure) (cf. chapter 4.6). The arc gap,
i.e. the spacing between the two electrodes during the operation of the lamp,
is only a few millimeters. Thus, the lamps come very close to the ideal of
a point-source lamp.
" H stands for mercury (Hg, lat.: hydrargyrum)
B stands for high luminance (B = symbol for luminance)
O stands for unforced cooling (original meaning, no longer
applicable today)"
* OSRAM
TECHNOLOGY AND APPLICATION – EDITION 1999/2000
MERCURY SHORT ARC LAMPS HBO® FOR MICROLITHOGRAPHY
http://www.osram.de/pdf/produkte/display_optic/hbo_ic.pdf
Downloaded Oct., 2006.