Publisher’sRoundtable
REDUCING SYSTEM FOOTPRINT AND
OPERATIONAL COSTS THROUGH CAREFUL
COMPONENT SELECTION
Rob Nine, Senior Marketing Manager, Pall Corporation
T
he costs to operate and maintain the latest-generation
semiconductor and LCD manufacturing plants have been
rising as these plants continue to grow in size. To reverse
this trend, manufacturers and their suppliers are finding ways
to reduce capital, operating, and maintenance costs, and minimize the footprint of their process equipment and distribution
systems. All of this must be accomplished without affecting
processes and yields.
There are many means by which cost and space efficiency
can be achieved. Process improvement, equipment maintenance and waste reduction, energy conservation, and equipment upgrades are among them. The implementation of carefully selected fluid-handling components is also important. A
vendor needs to work closely with its customers to identify specific challenges to size and cost reduction that could be solved
by using more efficient components. To accomplish this, new
products need to be developed.
The traditional large-flow gas housings used to filter bulk
clean dry air (CDA) and nitrogen present a challenge in terms
of their size. Pall has developed a large-diameter filter cartridge
to replace the traditional, smaller-diameter filter products used
for this same purpose. One 40” large-diameter filter takes the
place of twelve 30” traditional filters. Customers have benefited from a smaller system footprint, as well as lower capital and
maintenance costs. For new installations, they have realized
average cost savings of more than 20% and maintenance savings in excess of 50%. Similar technology has been introduced
for point-of-use (POU) on display manufacturing equipment. It
will enable increased flow rates with minimal impact on the
system footprint. This is critical where additional space is
almost nonexistent.
Increased operational and maintenance costs can result
from the unreliability of oxygen analyzers with zirconium oxide
(ZrO2) sensors. Such analyzers are used in critical semiconductor processes such as low-temperature RTP, ALD, PVD,
and CVD. Impurities in the process exhaust gas can cause
interference with the electrode material in the analyzer, resulting in frequent calibrations and costly process downtime. Our
solution was to develop a purification technology, which combines a metal catalyst with a metal filter. The purifier can be
installed upstream of the analyzer and will remove harmful
contaminants from the process stream. The result has been
increased uptime and reductions in the number of calibrations
by as much as sevenfold.
Aspects of the plasma etch process can result in higher
maintenance costs and decreased yields. During this process,
carbon monoxide (CO) is frequently added to the fluorocarbon
gas in order to enhance the selectivity process, particularly
32
gases and TECHNOLOGY
where high aspect ratios are
required[1]. CO is known to react with
certain metals, including nickel and
iron, forming harmful metal carbonyl
complexes. If these impurities are not
removed, they may be deposited on the Rob Nine
wafer, causing electrical shorts and a
reduction in die yield. Gaskleen® purifiers have been shown to
reduce these metal carbonyls to levels of less than 1 part per
billion (ppb). Harmful moisture impurities can also be
removed to similar levels. The removal of these types of impurities translates to longer on-stream life and fewer changeouts,
resulting in both increased production and cost reduction.
There are additional ways in which the purifiers save on
space and cost. Since they contain particle filters, and are similar in dimensions to particle filter assemblies, a one-for-one
replacement can be made without additional changes to the
distribution system. Their compact size allows them to be easily installed on the main feed lines or at POU on the gas stick.
These purifiers can be operated at ambient temperatures, so
an additional heat source is not required. Additional heat
sources raise capital, maintenance, and energy expenses.
Components have become more compact as a result of surface mount (top mount) technology, which was introduced several years ago. This technology has enabled gas stick manufacturers to reduce the size of their gas boxes. Since all components have similar base sizes and sealing surfaces, different
components on a common substrate can be easily interchanged. A top mount sandwich filter has been developed,
which can be installed between the substrate and another top
mount component. This enables customers to free up a space
on their substrate, reducing the overall length of the gas stick
and size of the gas box. It also allows the addition of a component to an existing installation when there are no free spaces on
the substrate.
Careful selection of system and other process components,
such as regulators, valves, gauges, and mass flow controllers,
can result in a smaller system footprint and a larger cost reduction. The technologies and components discussed in this article are alternatives that can help achieve these results.
1. R. Chakraborty, K. Brown, M. Horikoshi, “Removal of Metal Carbonyl
and Moisture Impurities Through POU Purification of CO Gas,” Solid
State Technology, (July 2005)
Rob Nine can be reached at 516-801-9104 or
rob_nine@pall.com
Continued on Page XX
May/June 2006