Chemical Management Gears Up for the Next Millennium

		At a Glance
	Competition and increasingly complex processes are driving various sectors of the semiconductor industry to focus on technological core competencies and look for specialized expertise outside the fab. The chemical management industry is evolving rapidly to fill these needs by providing these resources even when they lie beyond its traditional fields.

The concept of chemical management -- having one party handle everything related to chemicals in the fab while providing on-site expertise at the customer's location -- is an idea originally conceptualized in Japan. The American semiconductor market learned about it through Motorola (one of the newer fabs in the late 1980s) primarily. Motorola MOS 6 (one of the newer fabs in the late 1980s) personnel experienced it in operation, working collaboratively with a Japanese supplier. Later Motorola approached its suppliers to try it in the United States for its MOS6 facility.

The practice took root and developed, and the scope of value-added services provided by the chemical supplier to the semiconductor manufacturer expanded and adapted to fit American needs. (Fig. 1)

Increased equipment uptime is a primary advantage of the total chemical management concept. Fewer interruptions take place in the product process lines, because the right chemicals -- in correct amounts and high quality -- arrive precisely when needed.

Where before the supplier's responsibility ended at the customer's loading bay, now it extends into the fab and even to production itself. This progression has followed the increase in complex processes and chemistries resulting from linewidth shrinkage, which has overwhelmed the basic chemical expertise found in the average fab. Since by definition, chemical suppliers are chemical experts, having that expertise grafted to the fab's resources was an inevitable step.

Chemical manufacturing/sourcing spectrum

Chemical management does not only involve supplying and managing chemicals, but getting exactly what the customer needs. As Hayes Anderson, business director for chemical management services at Olin Microelectronic Materials (Norwalk, Conn.), stated, "We are a very broad-based supplier with products that include chemicals, diffusing chemicals, process chemicals, and photoresist. Although for the majority of our accounts we mostly manage our own chemicals, we will do third-party sourcing if the customer requests it, or as an extension of our product supply."

Olin will manage competing products and will bottle, stage, warehouse, and deliver them to customers as it does with its own chemicals. Even if the customer buys a competing product directly, Olin will still provide logistical support, warehousing and JIT delivery.

This is common practice with chemical management companies, and while Olin does not guarantee the purity of another company's product, the company warrants that its handling will not contaminate it.

If a customer suspects the quality of a batch of chemicals, then with the customer's consent and that of the original supplier, the chemical management company will perform quality assurance testing. Chemical manufacturers are very circumspect about this, because the other supplier may not be only a competitor, but a vendor and client as well. It is common practice among chemical suppliers to maintain relationships with competitors, purchase or sell them raw materials for product manufacture, or even use OEM finished products and bottle them with their own label.

Purity, delivery and storage considerations

Fig. 1. Services offered by chemical management companies have expanded well beyond the traditional to the production, transport, storage and delivery of chemicals to the fab. They are rapidly becoming a one-stop source of specialized knowledge and expertise that their customers can tap into when necessary. (Source: Olin Microelectronic Materials)

Chemical management frees the fab from warehousing large quantities of chemicals and reduces the requirement of complying with environmental and safety storage regulations. Providers always work in concert with a local warehouse, sometimes owned by them and generally close to the customer. There, adequate chemical inventory levels are maintained for JIT deliveries coordinated to meet customer needs. (Fig. 2)

Purity is an ongoing concern, and the ability to produce (and deliver) ppt-purity-level chemicals is a keystone of the chemical management business. Chemicals must not only be delivered at those purity levels, but be maintained through the distribution system as well. Since the chemical management company is also responsible for maintaining the distribution system's integrity, its obligation for purity ends at the point of use, where the fab assumes control of the process.

Yield improvement is chemical management's real value. This can result from just having properly handled fresh chemicals when they are needed, in the quality and amounts needed. As Anderson stated, "Where we operate with customers who have similar multiple locations, and some locations subscribe to our service and others don't, the differences are clear. Benchmarked against their sister fabs, ours always show better yields."

Containers and distribution systems

Although basic semiconductor chemicals have not changed much, purity levels save. Considerable resources and effort are invested to ensure packaging will sustain and maintain the chemical's purity. This goes beyond investing time and money. Relationships are established, and proprietary technology is developed.

Fluoroware (Chaska, Minn.) is typical of the materials-management industry in that it addresses different directions in the distribution area. John Goodman, the company vice president of engineering and technology, said he sees the increase in chemical volumes as an important trend. "This is driven by 300 mm (still a way out) and the need for greater manufacturing operations efficiency," he said. "Another factor is fab size."

Fig. 2. The total chemical management concept requires that well-trained technicians and engineers be stationed on-site at customer locations to perform various services, including monitoring chemical supply to prevent down time and slowdowns. (Source: Ashland Chemical)

Goodman observed that although it is too early to talk about 300 mm fabs, newer 200 mm fabs are very large. "This means we must overcome more head space when pumping chemicals from a facilities area to point of use," he said. "We're responding to higher volume chemical delivery requirements with larger-diameter fittings, larger piping systems, as well as higher flow valves. This isn't as easy as it sounds -- these components deal with high-purity, extremely corrosive chemicals and mustn't add anything to the chemistry."

Experience has led Goodman to conclude there is no such thing as "chemically inert." Like its peers, Fluoroware must cope with chemicals being introduced to improve process efficiencies, which attack materials previously deemed impervious. Some new chemical developers have additives that attack fluoropolymer components. This will be exacerbated by the chemistries developed to support copper technologies.

Changes occur not only in pipes and fittings, but in packaging. For years the industry used bottles. Then purity and cost considerations led to 55-gallon drums and other containers. Now the move is to large chemical containers, isotainers and tanker-truck-sized chemical container delivery systems. Large containers present a smaller surface area to the total volume being transported, minimizing contamination potential.

"Our products are principally composed of fluoropolymers," Goodman explained. "Because they must handle ppt or even ppq chemicals without contamination, raw material purity is of paramount importance. We have extensive analytical facilities to test the resins that we manufacture into our products. Many of our high-end application products are either made or cleaned in cleanrooms. We work with our suppliers, DuPont and others, to continuously improve material quality."

Handling chemicals so they remain uncontaminated is an on-going concern for distribution systems. Minimal intervention and quick connection points that enable a line feeding into the fab to be attached to a container without introducing contamination are important features. Along with larger chemical containers and better connection systems, Fluoroware has redesigned a number of products to provide maximum throughput with minimal pressure loss. This has required new valve designs to do away with turbulent flow areas in the valve. "Products introduced over the next year or two," Goodman predicted, "will have a completely different look."

The Age of "rented" chemicals

Initially, chemical management meant getting the product to the customer site and helping him or her use it. Now, it can also mean "renting" chemicals, much in the way an automobile is leased.

Chemical management companies are in a unique position to dispose of and recycle the chemicals they provide. This service is evolving rapidly toward full life-cycle chemical management. The company manufactures the chemicals, delivers them, facilitates their use and takes them back for proper disposition. Sometimes uses can be found for "spent" chemicals, providing added value to the customer and extra profit to the supplier. Sulfuric acid is a good example. Being one of the larger-volume chemicals used by the semiconductor industry, it makes sense economically to reclaim it.

The chemical management company produces sulfuric acid to customer purity specifications, packages and ships it. Within the fab, chemical management personnel distribute it through the distribution system. The chemical is used and later stored in a dedicated bulk container. When it reaches a certain volume and it becomes economically viable, a customer or supplier with a sulfuric acid specification that can be met by the "spent" chemical is found. If there is no commercial outlet, other means are found to recycle it within the EPA's definitions.

Looking to 2001

It is unnecessary to be Nostradamus to foresee that the trend toward collaboration between experts in different fields will increase quantumly. Fabs everywhere are demanding more value-added services and expertise from their suppliers, while trying to reduce their number of vendors.

Obviously, chemical management companies are not universal experts. To offer a wide spectrum of services they must work with other companies. Most chemical management companies are actively forming or considering alliances with other companies, such as gas companies -- Olin with Matheson Gas, for example. These alliances will eventually cover the distribution equipment itself. "Total turnkey is where we see the future," said an executive of one of the larger players. "Not only in chemicals, gases and equipment, but equipment design as well, its construction, installation and operation."

Don Mitchell, president of Schumacher (Carlsbad, Calif.), said there are three industry drivers altering the way customers handle consumables. "The first is the investment level required to stay in business," he said. "That'll go though the roof when they transition to 300 mm. Add to that the cost of specialized expertise required to protect this investment and keep the fab running."

Mitchell said he foresees that the move to 300 mm will result in greater demand for supplies of chemistries and gases, higher water consumption and higher energy costs. Additional equipment will be needed in the back pad as well, to get these different materials into the fab. "Fabs have to attenuate these incremental expenses by having suppliers take more of an own/operate view on much of the equipment," he said. Mitchell predicted fabs will ultimately require the chemical management operation to generate some chemistries on site and assume some responsibility for overall facilities management.

Mitchell views competitiveness as the second driver. "Because the semiconductor industry is so competitive and so global, it increasingly must focus on its core competencies, device design and manufacturing," he said. "Customers do not want to play referee between capital equipment suppliers, chemical suppliers and gas suppliers. If a single party handles everything, their human (to say nothing about capital) resources are tremendously leveraged."

The final driver is technology-specific, according to Mitchell. "As devices get smaller, complexity increases," he said. This manifests itself in new materials and new process steps. "A whole group of new liquid precursors is coming in. New slurries are coming on line and soon there will be no one-stop shopping for one slurry, especially with copper coming in." Added to this are the new specialty gases.

Chemical/gas management companies must operate and provide services seamlessly and globally. The new integrated companies will have to own much more of both the chemistries and the equipment to stay in business. This means far-ranging preferred alliances that enable them to offer an exclusive list of products, with the economies of scale driven by the partner company.

Ashland Chemical Company (Dublin, Ohio) is also moving toward gas and chemical management consolidation. "We work with several gas suppliers," stated Bill Whitlock, director of technology and management services for Ashland Chemical's Electronic Chemicals Division.

Although we have not yet formalized an alliance with any (supplier), there is no doubt in our minds that the chemical and gas people must join to provide a consolidated service."

Fig. 3. Air Products and Chemicals, Inc. (Allentown, Penn.) manages chemicals and industrial gases at the White Oak Semiconductor facility near Richmond, Vir. White Oak is a joint venture between Motorola Semiconductor Products Sector (Phoenix, Ariz.) and Siemens Semiconductor Group. (Source: Air Products)

Still, Whitlock advised customers to moderate their enthusiasm. "Unquestionably, the consolidation of chemical and gas management saves money and infrastructure," he said. "But there is a crucial caveat here; there are infinite degrees of expertise. Some companies try to supply gases, chemicals, equipment, garments -- everything. Some important know-how can get lost in the mix. Make sure the company has the value-added expertise and resources that you need or you'll lose out by going to them."

Whitlock said he sees expertise as chemical management's principal contribution. "We're heavily involved in chemical technology," he said.

We work with fab engineers to solve problems at the fab. Our on-site people are chemical experts who work side-by-side with the research and leading-edge fab engineers to develop new chemistries and processes; all these resources are right at the fab."

This on-site presence enables some chemical management companies to take ownership of a fab's entire distribution system, including maintenance. If there are issues such as pumps or valves failing or temperature control probes that add impurities, experts tackle and solve them before they cause reliability problems with yields.

Chemical management also looks at how new chemicals may affect distribution systems. As new semiconductor generations evolve, more complex chemistries are used. New additives, surfactants, chelating agents and other chemicals are added to the basic RCA chemistry. This enhances performance, but it may also attack gaskets and affect particle levels.

As a gas/chemical management company, Air Liquide Electronics (Walnut Creek, Calif.), also advises on the overall design of a fab's chemical distribution systems. "We work with the customer's project team, the A&E firm and sometimes the general contractor," explained Dave Nachreiner, director of gas and chemical operations. "We keep gas and chemical issues from being forgotten when allocating space. It is very expensive to build, then have to go back to try to troubleshoot for lines, equipment and utilities."

One third of a typical Air Liquide site services team is made up of experts transferred from existing operations, with the balance consisting of people hired locally and trained by the company. Typically, the team reports to only one fab representative, usually the facilities manager or the manager of gases and chemicals. From early on, the team is responsible for procedures and does, in fact, write them. Because this makes them part of the fab's ISO certification process, SOPs are formatted to make them compliant with the customer's document control procedures.

The team participates in the daily fab operation meeting, and in engineering facilities meetings where discussions take place regarding new tool installation, troubleshooting existing tools, expansion plans, problems or productivity data.

There is a consensus that in a few years suppliers unable to completely own gas and chemical issues and assist in fab construction or the most minute operating detail will not survive. Inevitably, semiconductor manufacturers are coming to depend more on their chemical management companies to do more than just gases and chemicals. (Fig. 3)

Nachreiner recalled when one of their customers ran into problems with an unreliable power supply at their Dresden, Germany facility. Since even a nanosecond glitch in power can affect plasma tools and ruin wafers, this was a serious concern.

"When they turned to us we realized we lacked the resources," Nachreiner said. "So we formed a joint venture with an expert company and put in a co-generation unit to supply acceptable power. Now we have the resources. Customers have almost infinite needs, and suppliers who cannot take complete ownership of these needs are not going to make it."

Some chemical management companies are going beyond strategic alliances and mergers, to planning in-house silicon processing capability and applications laboratories. It is becoming impractical to use customers' fabs as experimental ground. As processes grow in complexity, chemical management companies will need the capability to process silicon and make ICs in their own fabs, where they can research and test. The coming of copper is requiring new chemistries, with considerable changes in CMP chemistry. Low-K dielectrics will also require whole new chemistries.

As Ashland's Whitlock stated, "Soon you won't be able to go to the customer and say 'trust me, this will work.' You're going to have to show him SEM photos of working vias and geometries proving that what you are advising will work."

Chemical management's entry into new fields may extend even further. An engineer at a leading equipment manufacturer, who asked not to be identified, pointed out that the semiconductor industry must come to terms with a dilemma. "Fabs used to be self-reliant when it came to developing new processes. This has changed over the years, and now it's mostly (the equipment suppliers) who define them. We must engage the specialty materials supplier who may have, or be able to develop an ideal chemical or material pre-cursor solution. This doesn't happen, because we see this as a threat to our ability to sell a new platform. Since, as equipment manufacturers, we wield more power over the buyer than the materials supplier, solutions that might be simpler and more cost-effective do not get in. This must change. There are difficult times ahead, and we must all work together to get through them."