Paper planning can make retrofits less complicated and more successful with minimum to no production downtime
by Lisa A. Coleman
One of the toughest construction jobs is retrofitting, upgrading or revamping a contamination-controlled manufacturing area. It poses many challenges for the designers, construction managers, subcontractors, facility managers and the facility personnel. Fast technology improvements—especially in semiconductor manufacturing as smaller design rules propel tighter contamination control levels—drive facility managers to demand more cleanroom space.
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Getting new cleanroom space into existing production areas is not always easy or quick. Retrofitting existing clean manufacturing space can impede current production and yield. In many cases, scheduled production downtime will occur for building renovations. However, construction and design experts agree that proper planning months in advance can make retrofits less complicated and more successful with minimum to no production downtime.
“The keys to a successful cleanroom retrofit project are planning, planning and more planning,” says Gregg Conboy, project manager at Erland Construction (Burlington, MA). Designing a retrofit and working out any potential problems takes about 75 percent of the project's time, construction takes about 25 percent, he estimates.
A clean sweep
In many cases, retrofits are a better choice than new greenfield construction. Existing building space, workforce and the manufacturing supply chain are all available locally.
“Good sites are very hard to find,” says Michael Fitzpatrick, program director at Lockwood-Greene (Tempe, AZ). For example, finding vibration-free sites is a difficult task in the San Francisco Bay area, he says. Some companies would have to go at least 100 miles away to find a good site that offered an available workforce, water, dependable power and suppliers, he explains. Therefore, renovating an existing site instead of building new is an attractive option, Fitzpatick claims.
Retrofitting fabrication facilities occurs more as the semiconductor industry moves to 300-mm wafers. As semiconductor manufacturers upgrade their equipment, they also need to upgrade their cleanrooms to meet the needs of the new equipment.
“As the Motorolas and Intels start switching over to 300-mm technologies, there is an abundance of smaller device equipment available on the used market,” says Conboy. “So other companies have started buying used equipment that typically processed six-inch wafers just to help increase their production,” he says. In many cases, these companies do not have enough space to accommodate the equipment, Conboy adds.
Other revamps, upgrades and retrofits are needed simply to improve production flow or because manufacturers are changing products. Or they may need to improve their class of cleanroom.
“A lot of cases where they change the room, they change it because their process has changed and we may need to just upgrade the cleanroom level. A lot of companies are expanding and need more space, so they'll take over non-clean spaces and turn them into cleanrooms,” observes Blake Hodess, president of Hodess Building Co. (N. Attleboro, MA).
Wireless semiconductor manufacturer Alpha Industries (Woburn, MA) decided to expand its fab and has been continuously retrofitting for two and a half years to increase production capacity and increase wafer starts, says Joe Torrice, Alpha's facilities manager. Alpha added 15,000 square feet of ISO Class 5, 6 and 7 (Class 100, 1,000 and 10,000) cleanroom space.
“We had a good infrastructure in place and we believed we could retrofit faster than greenfield,” Torrice says. Prior to the retrofit project, Alpha was producing 200 wafer starts per week. Now its production has increased to 600 wafer starts per week. “Adding more clean space is what we needed,” he adds.
Back to the drawing board
After a decision to retrofit has been made, the best place to start is with the architect/designer and the construction manager/general contractor. “The quality of the design documents and the quality of the construction efforts are two issues, but supporting ongoing production is a different issue,” says Thomas Hansz, AIA, president of Facility Planning & Resources (Pittsburgh). “You can have the best design in the world, but if the design is such that it will shut down production, it's not good.”
Hansz suggests hiring an architect and developing the program first. The next step is adding the builder/contractor to the team. “Defining the project first will help you hire the appropriate contractor/construction manager,” he says.
Hansz says he promotes taking time to find the right team even if it takes longer than expected. But he cautions owners that contractors are not always qualified as cleanroom programmers.
Hodess's company, on the other hand, has had great success when the designer and the general contractor are brought in together at the beginning of the retrofit project. “It's much more cost effective that way,” he adds. Many owners want their retrofits done quickly and as inexpensively as possible. Having both the designer and contractor there from the beginning of the planning stage helps save money and keeps the project on schedule, he explains.
Getting a construction manager onboard at the same time as the design group facilitates communication, adds Conboy of Erland. “We really promote getting a construction manager onboard as early as you're getting a design group onboard,” he says. “The design group has a concept of how the building is supposed to be designed but the feasibility of its construction is not necessarily the best. An engineer might come up to us with a scenario of how they want the equipment installed but they may not know that it's not the most practical way of installing it,” Conboy continues.
Owner's homework
The owner needs to collect very specific information before the retrofit can begin. This begins with a tool matrix detailing equipment and its requirements for operating, such as, utilities, power, gas, drains and exhaust requirements. Based on this matrix, heat loads can be determined and then the correct air handlers, exhaust systems, etc. can be chosen. Typically, the construction manager will verify the tool matrix and ask the subcontractors to do the same.
Using the tool matrix will also help identify all mechanical system and infrastructure requirements for the retrofit. But thorough analysis of a building is best. Many times as cleanroom floors or ceilings are being taken apart, the contractor will discover that the documented specifications were inaccurate.
“When a cleanroom is opened up during construction unforeseen situations can occur,” Hansz warns. “For example, there may be a four-inch slab instead of a six-inch slab, or a 24-inch duct instead of 12 inches. These are unforeseen conditions that could have been understood in the programming and planning stage.” The existing facility may not be built as designed but a thorough analysis of the building will help alleviate unexpected surprises during construction, he adds.
The big three
Production, cost and space are all impacted when an existing operational cleanroom is retrofitted. “The key word in retrofits is time. The idea is that renovations are usually hampering production, and a firm that can get in and out quickly is ideal,” Hansz says.
For example, Alpha Industries' retrofit, which was managed by JM Coull Inc. (Concord, MA), occurred while Alpha was producing wafer starts, Torrice of Alpha says. Torrice says he was tasked with keeping production moving because the company's business commitments would not allow any major shutdowns. “There were a lot of challenges,” says Torrice. “But there were no shutdowns even though we had a major chill water renovation,” he adds.
Temporary chillers and cooling towers were constructed outside of the plant, which allowed Alpha to continue its production, Torrice explains. “We continued renovations and used the life support of the temporary chilled water,” he adds. “We were able to switch to the new, renovated chillers on the fly with no downtime.”
Scheduling and coordinating retrofits with ongoing manufacturing gets complex and challenging, says Fitzpatrick of Lockwood-Greene. “You must tailor construction activities to the point where you are not impacting existing process lines,” he explains. “This takes a lot of cunning, ingenuity and creativity,” Fitzpatrick notes.
“It is unrealistic to expect to maintain optimum production levels during retrofit, but proper planning and sequencing of work ensure minimum unexpected events that effect budget, time and facility operations,” agrees Timothy Loughran, project manager of the cleanroom design/construction firm AdvanceTEC (Richmond, VA).
Renovations and retrofits are rarely cheaper than building new facilities, Fitzpatrick says. The least-expensive part of new construction is the brick and mortar, while the expensive part of renovation, especially in semiconductor fabs, is tying into existing gas and chemical lines, he explains.
“You have to shoehorn a process line into a facility not originally designed for it,” Fitzpatrick says. Some fabs may have put in state-of-the-art high-purity water 10 years ago, but upgrading it today requires ripping out the old system and installing a new one, he continues. “Routing utilities are not based on the best routing technology but what's best for the facility,” Fitzpatrick adds.
However, retrofit cost is also a summation of the price of the work along with any lost production, potential for lost yield and inconvenience, Loughran says. “Cost is not necessarily equal to price.”
Renovating a clean manufacturing environment while production occurs drives the cost of the project up, Conboy of Erland says. Retrofit work schedules need to be coordinated with production so that if a utility tie-in needs to be completed, the contractor knows when a work stoppage has been scheduled, he explains. The clean environment needs to be protected and temporary partitions should be erected, typically with metal studs and materials such as Tyvek, Conboy adds. “These things do drive up the cost,” Conboy notes.
In some cases, facilities are operating 24-hours per day, and shut downs can cause problems and some of the systems, such as scrubbed exhaust systems, cannot be shutdown, Conboy says. “If you were to shut these units down, all those condensables that were pulled through the exhaust would actually condense and migrate back down the duct work to create a dangerous situation,” he explains.
Another area where facility owners need to be wary is the required amount of space for their retrofit. Is there enough space for construction activities such as clean tool storage, wipe down rooms and construction personnel gowning?
For example, if an owner has 20,000 square feet, 10,000 may be used for a chase and 10,000 may be used for the cleanroom, Hansz says. Clean construction staging may require another 2,000 to 5,000 square feet, he continues. Managing laydown and storage space for construction materials and components is extremely critical for the retrofit schedule, Hansz explains.
“Proper provisions for material handling will significantly cut labor cost and the potential for contamination generation,” Loughran says. Moving construction back and forth adds to the possibility that materials may be damaged or contaminated, he notes.
“Careful advance planning and construction management allows for just-in-time deliveries and ease of staging of materials for installation, requiring minimal staging areas,” Loughran adds.
Opening lines of communication
Communication among the facility's personnel, the construction manager and the designers and engineers is essential. The best advice is “communicating and making sure everybody knows what's going on and what's planned,” says David Novak, Erland's director of business development.
Hansz recommends the following tips to ensure success for each retrofit project:
- put together a good team that will work well together and can help the facility owners meet their goals;
- research how operations will be affected during retrofit and plan for any work interruptions;
- assign a full-time project manager or representative to the renovation and don’t overload your full-time staff with full-time project responsibilities;
- evaluate space needs and make sure enough exists for clean tool storage and gowning;
- investigate the facility and make sure the owners, designers and construction managers have an accurate understanding of existing conditions;
- plan for change.
“From the time the project is first conceived until the time it is done, you are probably going to go through four or five major changes,” Hansz says. “Either the toolset changes or the architectural configuration changes therefore you must plan for change.”
POINT/COUNTERPOINT
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Point: Define project first.
“A trend we're seeing is that construction managers want to be one-stop shopping — and this is not always in the client's best interest. Instead, hire an architect and develop the program first before adding the builder/contractor to the team.”
Counterpoint: Choose team at project outset.
“It's nonsense to think that one or the other should be there first. The old traditional ways of doing design, like bringing in a designer first then a contractor, are not cost effective or schedule effective in today's economy. Having both the designer and contractor there from the beginning of the planning stage helps save money and keeps the project on schedule.”
Operational plans for retrofits
By Timothy Loughran
Retrofitting an existing operational cleanroom carries an uncommon set of issues and concerns. Addressing these issues in advance of construction will ensure a successful retrofit project while maintaining targeted production and existing yield levels. After considering retrofit issues, such as cost, access and storage as well as choosing a contractor, an operational plan is needed before proceeding with retrofitting.
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The first step is surveying the existing facility to determine how closely documented plans reflect actual existing conditions. Identifying how reliable facility plans are will significantly effect the aggressiveness of the schedule, material stock requirements and manloading. Also, try surveying acceptable components within the marketplace to match existing facility conditions where required. Material selection may depend more on its availability to meet the required schedule than anything else. Set performance criteria and prioritize price, product and delivery issues.
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Create a detailed work sequence and incorporate it into a preliminary schedule. This schedule can then be compared with the facility's production requirements and other potential events that require schedule flexibility. In areas of schedule conflict the team must determine priorities and adapt requirements appropriately—this is most critical to project success.
A potentially significant cost issue is excess material stock. How much and what kind of excess stock materials are required must be considered along with potential for restocking, the associated charges and the critical nature of certain sequences along with lead time availability of potential shortfall products. Local sourcing of as many materials as possible helps properly plan for possible contingencies.
With the planning complete, facility preparation begins. A proper build-clean protocol must be established to ensure contamination generation is kept at minimum. In areas where construction workers interface with operating production areas, cleanroom construction protocol must match the operating protocol. Construction area separation must be maintained at all times. To inhibit contamination, special consideration should be given above the ceiling, in duct systems, plenums, return walls, conduit, and below the floor.
Removing protection from existing equipment and curtaining off construction areas can now be completed, however, it must be done with painstaking detail. Any compromise of the existing operational facility delays in re-starting production or affects yield percentages in the renovated area. Whenever and wherever possible, equipment should be removed or isolated from the construction area.
Any demolition should occur by following a sequential plan. Any materials removed from the controlled area should be properly disposed. Hazardous materials should be identified in advance and removed according to regulations.
Contamination-generating materials should be properly bagged upon removal and immediately removed from the critical environment. A staging area for outgoing and incoming materials should be established. Personnel should wear badges. Critical environment workers should be easily identifiable from non-critical environment workers. They should follow established acceptable protocol at all times.
Salvageable products that are slated for re-installation or re-use should be identified immediately upon removal. These products should be moved to the staging area where they are cleaned and wrapped for storage. When re-installing they should be unwrapped and cleaned following incoming material protocol.
With demolition complete, re-installation of the salvaged materials and new material installation can begin. All materials should be treated as new. Follow incoming material protocol. Construction should occur under a build-clean protocol, which is equal to or exceeds that of the operating facility. Final (super) clean should occur prior to removing temporary construction barriers. Finally, move equipment through the staging area by using incoming material protocol placed under operating protocol conditions.
Timothy Loughran is project manager for AdvanceTEC (Richmond, VA). He was formerly the manager of design/build services for Performance Contracting Inc. and division manager for the cleanroom engineering division of Cleanroom Products. He has over 15 years experience in the cleanroom industry and has published papers on numerous construction-related topics.