v/EPA
United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S-92/050 October 1992
ENVIRONMENTAL
RESEARCH BRIEF
Waste Reduction Activities and Options for a Manufacturer of
Systems to Produce Semiconductors
Alan Ulbrecht and Daniel J. Watts*
Abstract
The U.S. Environmental Protection Agency (EPA) funded a project
with the New Jersey Department of Environmental Protection and
Energy (NJDEPE) to assist in conducting waste minimization as-
sessments at 30 small- to medium-sized businesses in the state of
New Jersey. One of the sites selected was a facility that manufac-
tures systems for vapor deposition of organometallic compounds or
metals used in the production of semiconductors. As part of the
manufacturing process it is necessary to test the systems using the
materials actually used in semiconductor production. Test deposition
of materials containing arsenic, indium, or gallium, among others,
result in much of the waste stream. A site visit was made in 1990
during which several opportunities for waste minimization were
identified. Options identified included changes in degreasing proce-
dures and modifications to filtering systems. Implementation of the
identified waste minimization opportunities was not part of the pro-
gram. Percent waste reduction, net annual savings, implementation
costs and payback periods were estimated.
This Research Brief was developed by the Principal Investiga-
tors and EPA's Risk Reduction Engineering Laboratory in Cin-
cinnati, OH, to announce key findings of this completed as-
sessment.
Introduction
The environmental issues facing industry today have expanded
considerably beyond traditional concerns. Wastewater, air
emissions, potential soil and groundwater contamination, solid
waste disposal, and employee health and safety have become
increasingly important concerns. The management and dis-
posal of hazardous substances, including both process-related
wastes and residues from waste treatment, receive significant
attention because of regulation and economics.
* New Jersey Institute of Technology, Newark, NJ 07102
As environmental issues have become more complex, the
strategies for waste management and control have become
more systematic and integrated. The positive role of waste
minimization and pollution prevention within industrial operations
at each stage of product life is recognized throughout the
world. An ideal goal is to manufacture products while generat-
ing the least amount of waste possible.
The Hazardous Waste Advisement Program (HWAP) of the
Division of Hazardous Waste Management, New Jersey De-
partment of Environmental Protection and Energy, NJDEPE, is
pursuing the goals of waste minimization awareness and pro-
gram implementation in the state. HWAP, with the help of an
EPA grant from the Risk Reduction Engineering Laboratory,
conducted an Assessment of Reduction and Recycling Oppor-
tunities for Hazardous Waste (ARROW) project. ARROW was
designed to assess waste minimization potential across a
broad range of New Jersey industries. The project targeted 30
sites to perform waste minimization assessments following the
approach outlined in EPA's Waste Minimization Opportunity
Assessment Manual (EPA/625/7-88/003). Under contract to
NJDEPE, the Hazardous Substance Management Research
Center at the New Jersey Institute of Technology (NJIT) as-
sisted in conducting the assessments. This research brief
presents an assessment of the manufacturing of systems for
vapor deposition of organometallic compounds or metals used
in the production of semiconductors (1 of the 30 assessments
performed) and provides recommendations for waste minimi-
zation options resulting from the assessment.
Methodology of Assessments
The assessment process was coordinated by a team of techni-
cal staff from NJIT with experience in process operations,
basic chemistry, and environmental concerns and needs. Be-
cause the EPA waste minimization manual is designed to be
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primarily applied by the inhouse staff of the facility, the degree
of involvement of the NJIT team varied according to the ease
with which the facility staff could apply the manual. In some
cases, NJITs role was to provide advice. In others, NJIT
conducted essentially the entire evaluation.
The goal of the project was to encourage participation in the
assessment process by management and staff at the facility.
To do this, the participants were encouraged to proceed through
the organizational steps outlined in the manual. These steps
can be summarized as follows:
• Obtaining corporate commitment to a waste minimization
initiative
• Organizing a task force or similar group to carry out the
assessment
• Developing a policy statement regarding waste minimiza-
tion for issuance by corporate management
• Establishing tentative waste reduction goals to be achieved
by the program
• Identifying waste-generating sites and processes
• Conducting a detailed site inspection
• Developing a list of options which may lead to the waste
reduction goal
• Formally analyzing the feasibility of the various options
• Measuring the effectiveness of the options and continuing
the assessment.
Not every facility was able to follow these steps as presented.
In each case, however, the identification of waste-generating
sites and processes, detailed site inspections, and development
of options was carried out. Frequently, it was necessary for a
high degree of involvement by NJIT to accomplish these steps.
Two common reasons for needing outside participation were a
shortage of technical staff within the company and a need to
develop an agenda for technical action before corporate com-
mitment and policy statements could be obtained.
It was not a goal of the ARROW project to participate in the
feasibility analysis or implementation steps. However, NJIT
offered to provide advice for feasibility analysis if requested.
In each case, the NJIT team made several site visits to the
facility. Initially, visits were made to explain the EPA manual
and to encourage the facility through the organizational stages.
If delays and complications developed, the team offered assis-
tance in the technical review, inspections, and option develop-
ment.
No sampling or laboratory analysis was undertaken as part of
these assessments.
Facility Background
The facility is a manufacturer of a vapor deposition system
used in the production of semiconductors. The facility manu-
factures the units and then tests them under simulated semi-
conductor production conditions using the actual chemical ma-
terials which are deposited on silicon wafers in large-scale
production. This testing produces the bulk of the waste which
is generated at the facility.
The facility is located.in a suburban area and employs about
100 people. The demanding quality standards of the semicon-
ductor manufacturing field are reflected in this facility and in the
care which goes into the manufacture of each of its units.
Manufacturing Processes
The facility produces the vapor deposition units by assembling
several components which are produced outside the facility.
Stainless steel tubing is used in the units for structural strength
and to minimize interference with the deposition process which
might occur with other materials. The facility carries out cutting
and forming operations on the tubing and generates some
metal working fluid wastes as a result. The tubing is also
etched with nitric and hydrofluoric acid and degreased with a
chlorofluorocarbon in an ultrasonic bath.
The completed units are tested under simulated semiconductor
wafer manufacturing conditions involving vapor deposition on
silicon wafers of materials containing arsenic, gallium, phos-
phorus, mercury, indium and other elements used in semicon-
ductor production. The vapors which are not deposited on the
test wafers are captured in stainless steel traps. The majority
of the waste streams from this part of the operation result from
the procedures to clean the traps for reuse. The cleaning steps
involve vacuuming with special "clean room" filters and then
washing with solutions which are somewhat specific for the
material trapped in the filter. The washing solutions include
caustic, hydrofluoric acid, ammonium hydroxide, hydrogen
peroxide, nitric acid, and sulfuric acid. The washings may
contain small amounts of chromium, molybdenum, gallium,
indium, arsenic, and phosphorus.
Existing Waste Management Activities
The company generates relatively small quantities of waste.
The challenge from a waste management perspective is that
while the total amount is small, the waste stream is composed
of several different types of waste which should be segregated
and managed separately. This raises costs and limits some of
the options for pollution prevention.
From the production portion of the operation, the degreasing
step using chlorofluorocarbon in an ultrasonic bath produces
no specific waste stream. On the other hand, the facility pur-
chases two drums of the solvent annually, indicating that
evaporative losses do occur. The solvent was chosen because
it is an effective cleaner and leaves no residue on the parts.
The facility is looking for an effective substitute. In addition, the
etching of stainless steel tubing generates about 2 drums per
year of mixed acid. The metal working fluid waste stream also
generates about 2 drums per year of material. Both streams
are sent offsite for disposal.
The testing and evaluation component of the operation gener-
ates additional waste streams. The vapor retention and recov-
ery system for the test setups include both stainless steel filters
and activated carbon traps. Efforts are made to clean and
reuse the steel filters. The carbon traps are sent offsite for
disposal. About 60 Ib/yr of this material is generated.
The steel filters are first vacuumed to recover loose materials
and then are washed with different solutions, depending upon
the material entrained in the filter. This process uses about 0.5
gal of each solution for each cleaning. Each year about 4
drums of ammonium hydroxide/hydrogen peroxide solution, 2
drums of sulfuric acid, and 4 drums of sodium hydroxide are
generated. These materials are sent offsite for disposal.
In addition, other waste streams include about 2 drums of
mixed solvents such as acetone and methanol used for the
cleaning and processing of the test wafers and about 2 drums
of plant scrap solid wastes including gloves and wipes used for
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cleaning the test units are shipped for disposal as hazardous
wastes.
Waste Minimization Opportunities
The type of waste currently generated by the facility, the
source of the waste, the quantity of the waste and the annual
treatment and disposal costs are given in Table 1.
Table 2 shows the opportunities for waste minimization recom-
mended for the facility. The type of waste, the minimization
opportunity, the possible waste reduction and associated sav-
ings, and the implementation cost along with the payback time
are given in the table. The quantities of waste currently gener-
ated at the facility and possible waste reduction depend on the
level of activity of the facility. All values should be considered
in that context.
ft should be noted that the economic savings of the minimization
opportunity, in most cases, results from the need for less raw
material and from reduced present and future costs associated
with waste treatment and disposal, ft should also be noted that
the savings given for each opportunity reflect the savings
achievable when implementing each waste minimizatbn op-
portunity independently and do not reflect duplication of savings
that would result when the opportunities are implemented in a
package.
The cost savings are calculated both in terms of avoided costs
of waste disposal and recovery of the value of raw material
used again. Also, no equipment depreciation is factored into
the calculations.
This type of facility represents a unique challenge to identifica-
tion of pollution prevention options. The facility has control over
the manufacturing steps and suggestions about modifications
of that can be considered. The facility has little control over the
use its customers will make of their units. Because the facility
must test the units under realistic operating conditions, the
employees must simulate the production processes of their
customers. Therefore, they have very limited control over the
types and quantities of the materials they use in the tests. They
do have some control over the procedures used to capture and
handle the waste streams from the tests. This situation is made
more complex by the fact that the chemicals used for the test
raise concern about worker safety because of potential health
effects.
Regulatory Implications
There are no significant regulatory issues which would impede
implementation of pollution prevention initiatives at this facility.
Tightened regulatory scrutiny on the use and manufacture of
chlorofluorocarbons can be expected to accelerate the change
to a substitute degreaser. Air quality regulations and technol-
ogy advancement may change the operations of semiconductor
manufacturers which will in turn cause modification of the
testing procedures at this facility.
This Research Brief summarizes a part of the work done under
cooperative Agreement No. CR-815165 by the New Jersey
Institute of Technology under the sponsorship of the New
Jersey Department of Environmental Protection and Energy
and the U.S. Environmental Protection Agency. The EPA Project
Officer was Mary Ann Curran. She can be reached at:
Pollution Prevention Research Branch
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
* Mention of trade names or commercial products does not constitute endorse-
ment or recommendation for use.
Table 1. Summary of Current Waste Generation
Waste Generated Source of Waste
Chlorofluorocarbon
Mixed Add
Annual Quantity
Generated
Evaporative loss from degreasing 110 gal
tank
Etching of stainless steel tubing 110 gal
drawing operation
Annual Waste
Management Costs
$ 3600 (raw material cost)
400
Water Soluble Oils
Spent Carbon
Cleaning Solutions
Mixed Solvents
Solid Wastes
Metal working lubricant and coolant
Carbon filters
Washings of stainless steel filters
Processing of test wafers
Plant scraps, gloves, and wipes
110 gal
60 Ib
1100 gal
110 gal
110 gal
750
200
2000
400
650
&U.8. GOVERNMENT PRINTING OFFICE: MM - SSO-4M7/WIM
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Table 2. Summary of Recommended Waste Minimization Opportunities
Waste Steam
Reduced
Minimization Opportunity
Annual Waste Reduction
Quantity Percent
Net Implementation Payback
Annual Savings Cost Years *
Chhrofluorocarbon
Cleaning Solutions
Scrap Waste
Change to aqueous-based solution
tor decreasing. Because
ultrasonic tank is already
available, such a change should
be facilitated.
Stop cleaning filters tor reuse.
More waste is generated by the
cleaning process than if the filters
were drectfy disposed of.
Consider how to reuse gloves and
how to dean using fewer wipes.
110 gal
1100 gal
100
100
11 gal
10
$ 3,600 0 immed
(It will be necessary to purchase an
alternative cleaning solvent, and an
aqueous waste stream can be expected.)
2000 0 immed
(It will be necessary to purchase more
filters and to pay for disposal of this
waste stream. The actual cost savings
will depend on the cost of the filters.
We can estimate about a$1000 savings.)
40
immed
* Savings result from reduced raw material and treatment and disposal costs when implementing each minimization opportunity independently.
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
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