RATIONALE FOR DFEHS Contributions by Bob Duffin, Motorola Corp.

 1999 Arizona Board of Regents for The University of Arizona

What is DFEHS?

DFEHS stands for Design for Environment, Health, and Safety. It represents a systematic approach to the design, manufacture, use, and final disposition of semiconductors that incorporates consideration for EHS impacts at the earliest possible stage. In the broadest terms, DFEHS is a systematic management approach for evaluating and mitigating EHS concerns at the earliest possible stages of process design or product life cycle. It includes ongoing evaluation during the product life cycle, while optimizing the balance between EHS priorities and factors such as cost, yield, cycle time, performance, etc.

Business Driving Forces for DFEHS

Decreasing cost – DFEHS often results in reduced material consumption, reduced cycle time, reduced regulatory bureaucracy, avoided delays, etc. These all translate into cost savings. DFEHS reduces operating costs and risks by reducing or eliminating storage, handling, training for use, safe management, site response, compliance requirements, and final disposal of hazardous materials and wastes.

Achieving sustainability for tools/processes – Early consideration of EHS impacts may help ensure that a tool/process is sustainable for the next technology generation. It at least ensures that EHS issues will not be the reason that the tool/process cannot be used later.

Minimizing time to market – Addressing EHS issues in the design and development stages will help avoid costly delays at the implementation stage. These could include permit modifications, EHS reviews, retrofits, etc. Unexpected or unprecedented regulatory changes and limitations on the use of hazardous materials can derail product introduction and new product development. DFEHS prevents such interruptions by anticipating these potential roadblocks.

Maintaining market access – Compliance with international standards, such as ISO or EMAS, may become mandatory to conduct business in many countries – especially in Europe. A DFEHS program is an essential element of these types of standards.

Increasing market share – EHS performance is now viewed as a distinct competitive tool. Customers may migrate towards companies with proactive EHS programs and environmentally preferable products – particularly in Europe.

1 Reducing corporate risk factors – In an era of severe cost constraints, corporations are keen to reduce operating risks to increase stakeholder value. DFEHS offers many risk reduction opportunities, such as elimination of hazardous waste treatment, storage, and disposal liability; reduction in workplace hazards (safety and hazardous material exposure risks); anticipation of bans or restrictions on critical materials; early identification of required permit modification; and planning new products with an eye toward eventual product and materials take-back.

Projecting Environmental Leadership – Many corporations are beginning to include EHS leadership as one of the core values of business.

Addressing Customer Concerns

As customers become more environmentally conscious, they are beginning to use their ‘green purchasing power’. They are concerned about the environment and are increasingly demanding environmentally friendly products.

Permits/Disposal

It is expensive and time consuming to obtain and comply with environmental permits. Likewise, it is expensive and time-consuming to appropriately dispose of the waste that we generate. Incorporating DFEHS concepts into our business will allow us to minimize the time and money that we spend on permits and waste disposal.

Hot EHS Issues

Global Warming

In 1995 the Intergovernmental Panel on Climate Change (IPCC), an international group of atmospheric scientists working under the auspices of the United Nations, concluded that there is a discernible human influence on global climate. Perfluorocompounds (PFCs), such as perfluoromethane (CF4), perfluoroethane (C2F6), sulfur hexafluoride (SF6), nitrogen trifluoride (NF3), perfluoropropane (C3F8), and trifluoromethane (CHF3) are potent global warming gases used in the semiconductor industry for plasma cleaning and etching.

Future CVD and etch process and equipment development at many semiconductor manufacturers should include actions to reduce or eliminate emissions of these gases through improved utilization, decreased consumption, use of non-global warming alternatives, and/or emissions abatement.

Water Use Reduction

Semiconductor facilities are typically the largest consumers of water in a municipality. Some people have estimated that up to 10,000 gallons of DI water may be required to process one 200 mm wafer from beginning to end. Furthermore, the ion exchange

2 process used to produce DI water is the single largest use of bulk chemicals and generates a great deal of waste. This adds significant cost to the products we make. The semiconductor industry’s water usage is also becoming a major concern for local municipalities and environmental groups. It has the potential of limiting where new factories can be built and may even limit factory production levels.

Case Studies – Motorola Corporation

Traditionally, people believed that it would cost money to address quality concerns. Then it was discovered that ‘quality is free’. Likewise, it has been discovered that by proactively addressing DFEHS concerns, companies actually save money, since 70% of EHS costs are “locked in” during the design process. DFEHS can also prevent delays in tool installations and process implementation, which translates to significant cost savings. Each of the case studies outlined below come from Motorola Corporation fabs.

Segregated Ammonia Exhaust System

Routing ammonia exhaust from the fab to an acid exhaust system created problems with visible plumes and interference with scrubber effluent testing. This was due to ammonia salts that form when the ammonia mixes with the acid gases in the exhaust. The solution was to retrofit the fabs with segregated ammonia exhaust and ammonia scrubbing systems. The retrofit cost ranges from $3-5 million. However, new fab construction of a segregated ammonia system costs approximately $1-2 million. If DFEHS would have been applied and the segregate exhaust requirement anticipated, several million dollars could have been saved.

Methanol to IPA Conversion

Methanol is commonly used as a solvent in the metal etch deveil and photoresist stripping operations of semiconductor manufacturing. Methanol, however, is a hazardous air pollutant under the Clean Air Act Amendments. Because the current abatement system for volatile organic compounds (VOCs) cannot destroy methanol effectively, the site could have been subject to the Federal Title V permitting program due to methanol emissions greater than 10 tons per year. Conversion of the processes to isopropyl alcohol (IPA), which is not a hazardous air pollutant and is less toxic than methanol, will save up to $300,000 in permitting costs. It also avoids the federal permitting program, which would have significantly decreased permit flexibility for the site and increase downtime spent on permit modification. Furthermore, the site might have had to spend $1-2 million in specific abatement equipment for methanol, since the USEPA is considering imposing maximum achievable control standards for methanol that could not be attained with the current site abatement. If DFEHS would have been applied during process development and IPA selected from the start, the cost to re-qualify the process could have been saved.

3 Water Reuse

Many fabs have several wet cleans tools that utilize water. These tools are often supplied with the proper plumbing to recycle water. However, most fabs do not have the network of plumbing to support the water recycle. If this plumbing did exist, it would cost approximately $7500 to hook up each wet bench for recycling. Instead, it will cost $4.8- 6 million to retrofit the fabs. Even at this amount, the payback will only be 15 months.

Tool Exhaust

A new tool for wafer cleans was set to be installed in place of an old system. It utilizes HF vapor instead of wet chemistry, followed by an IPA dry. The current plumbing was hooked to solvent exhaust, and HF vapor was not used in the fab prior to the introduction of this new tool. The start up was delayed while ducting modifications were made to plumb the new tool effluent to the acid exhaust system.

Pump Oil Reclaim

A system designed to reclaim synthetic oil in vacuum pumps saved over $220,000 during the first two years of use. It consists of rough and fine filters to remove acids and other impurities. The cost of new oil is $170-179 per quart, while the cost of reclaimed oil is only $0.62 per quart.

Consequences of No DFEHS

Failure to address EHS issues can result in severe penalties. Some examples or permitting delays, regulatory fines, and criminal prosecutions are as follows:

 Under Arizona’s new air permitting rules, it takes approximately 18 moths to obtain an air permit. Designing manufacturing processes without hazardous air pollutants (HAPs) can eliminate the air permitting process.

 Millions nationwide have been spent on cleanups of contaminated sites.

 Currently, there are over 100,000 environmental regulations in the United States, and more are passed every day. Proactively implementing concepts lessens concern about being out of compliance.

 In 1983, the average fine for violating RCRA (Resource Conservation and Recovery Act) was $8,460, and in 1989, the average fine was $103,000. This trend has continued.

 Corporations do not go to jail – individuals do. Violation of environmental regulations may result in personal criminal liability for employees, even if the individuals involved were not aware of those regulations. Incorporation of DFEHS

4 into business practices, in concert with early involvement of EHS personnel, can minimize the risk of unintentional violation of environmental laws.

 Between 1983 and 1990, the Justice Department received 703 criminal indictments for environmental crimes, and 517 resulted in guilty pleas. Over 30 million dollars in criminal fines and 342 years of jail terms were imposed as sentences.

Incorporating DFEHS concepts into business minimizes the opportunity for regulatory fines and criminal prosecutions to occur. Minimizing chemical usage and the amount of pollution (air, water, and solid) generated will minimize the opportunity for us to violate environmental regulations.

Long Term Environmental Trends

There are many policies and standards being developed on a domestic and international basis that deal with EHS issues. These standards have a significant impact on the semiconductor business. Many countries, especially in Europe, will be adopting EHS- related standards for companies they do business with. There is also legislation involving restriction of certain materials in products or take-back of products at the end of useful life.

What Can You Do?

Engineers can practice DFEHS by following the hierarchy of reduce/reuse/recycle.

Reduce

Reduce energy and water use, chemicals, etc. in support of the conservation of natural resources. Reduce pollution at the source whenever possible Reduce the toxicity of chemicals used Reduce employee exposure to chemicals Reduce the use of chemicals by optimizing processes

Reuse

Reuse previous designs and processes that minimize impact on the environment. Reuse shipping packaging. Design shipping packages to minimize the impact on the environment while not compromising the protection of the product.

Recycle

Recycle or reuse the waste or by-products generated wherever pollution cannot be reduced to zero at the source. Purchase recycled products wherever possible. Utilize locally recycled materials in transport packaging.

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