Planning is key to successful retrofitting
Routine retrofitting has become a fact of life for most cleanroom facilities. Here are a few tips to make the process a little less painful.
By Sheila Galatowitsch
It`s rare these days to find a fab or equipment supplier not involved in some form of retrofit, expansion or upgrade project. The reason can be summed up in one word: change.
“Change is the only constant in our industry,” says Bob Anderson, director of facilities for Applied Magnetics (Goleta, CA). Operation and maintenance personnel “must have on their plate that change is eventually going to come. And they need to be planning how they are going to support these changes.”
Anderson is in the second phase of a major expansion to increase production capacity for Applied Magnetics, a manufacturer of magnetic recording heads for the disk drive industry. Modifying, retrofitting and upgrading the company`s facilities are a never-ending project, he says.
“The retrofit of our cleanroom is a continuous situation. We are constantly changing production tools, which drives changes in the utilities, the architectural pieces of the cleanroom and some of the airflow conditions.”
The routine retrofits include changing the physical dimensions of service aisles to accommodate new, larger vacuum deposition equipment. That requires the relocation of process utilities and electrical upgrades to current electrical rooms and substations. The company is also upgrading some of its clean areas from Class 1,000 to Class 100 and from Class 100 to Class 10.
“Instead of moving to another site or another city, we wanted to take advantage of our resources already in place — the engineering team, maintenance team, equipment and our other resources here that support the wafer fab. We felt that it would be too disruptive and not cost-effective to run a parallel team. That was one of the biggest reasons we decided to retrofit and expand the current wafer fab here,” Anderson says.
“The facility before retrofit and expansion was basically an old office building with wooden beams for roof support and an old built-up roof. We decided to totally demolish 20,000 sq. ft. of the existing building and start over with a high-bay structural steel system.”
In the first phase of expansion completed last year, 8,000 sq. ft. was added to a 10,000 sq. ft. fab. The second phase, a $14 million expansion begun in January, will add 16,000 sq. ft. of cleanroom space and 4,000 sq. ft. of chemical support areas. The project will be completed in December. Both the expansion and continuing retrofit projects have been completed while the company`s round-the-clock manufacturing operations continued.
There are generally two kinds of retrofits: cleanroom and utility infrastructure, says Kent Peterson, chief mechanical engineer at P2S Engineering (Long Beach, CA). New processes typically require new tools, which require modifications in utility infrastructure, as well as upgrades to the room.
For chip manufacturers, the conversion to 300 mm tools will create a gigantic jump in retrofits, says Curtis Cline, vice president of the advanced technology group at Faulkner Construction Company (Austin, TX). The biggest challenge will be increasing ceiling heights. “We will need to ensure that there is structural space in the facility. We may have to lower the floor and raise the roof in many of these facilities to accommodate the new tools.”
Equipment suppliers to chip manufacturers are also upgrading facilities to satisfy their customers` demands that equipment be manufactured in a clean environment. Many of these retrofits are upgrading Class 10,000 manufacturing areas to Class 1,000, and adding Class 100 packaging and testing areas.
Everywhere, facilities managers are looking for ways to squeeze as much earning potential as possible out of an existing facility. If you are anticipating a retrofit or upgrade, you are not alone. Following are some tips on conducting a successful retrofit or upgrade.
When is a retrofit required?
If you are putting in a new tool set, changing your processes or otherwise upgrading manufacturing conditions, you will need a retrofit, says Tim Loughran, manager of business development at Performance Contracting Inc. (Phoenix, AZ).
Most retrofits are driven by tooling changes, either when upgrading the tools or increasing wafer sizes, says Peterson. Changing the tools can typically result in utility infrastructure upgrades to handle larger loads.
“Cleanroom facilities include both `clean space` and the infrastructure that supports it, such as chiller plants, process utilities and the electrical distribution system. Even though you may not physically require any wall changes, you could require a retrofit on the infrastructure due to increasing loads,” says Peterson.
For example, a six-inch wafer line requires twice as much power, more process cooling, and increased exhaust and HVAC requirements than a three-inch line. Careful monitoring of existing utility loads will disclose which systems are getting close to the maximum capacity and require retrofits to expand capacity. “It`s important to know what the current load is on those systems,” says Peterson. “Then, when you are faced with additional requirements, you will be able to make an educated decision whether the infrastructure can handle the additional loads.”
When and how can operations be maintained during the retrofit?
Maintaining operations during a retrofit depends on the nature of the retrofit, say these experts. For a retrofit in existing fabs where one area of the fab is being renovated, that area can be isolated from the operational area within construction barricades, shut down and then brought back on line after renovation, while maintaining operations in the rest of the fab, says Peterson. For fab expansions, operations can be maintained by carefully planning tie-ins to existing systems or larger tasks during normal operational shut-downs, such as the Fourth of July, Christmas and New Year`s holidays, or a time that least impacts operations.
The only reason to halt production for construction is when a product is being phased out and will no longer be produced, he says. The entire area can be retrofitted and then brought back on line.
Successfully maintaining operations during a retrofit depends on how well the project team plans for vibration, dust and contamination issues, humidity, pressurization, egress and other factors that could impact operations. “It takes very little to upset a fab,” says Peterson.
Moreover, it is unrealistic to expect to maintain optimum production levels during a retrofit, says Loughran. Proper planning and sequencing of work will ensure a reduced, but reasonable level of production during the upgrading program.
Another way to maintain operations during a retrofit is to do the retrofit in pieces rather than all at once, advises Loughran. “You might want to retrofit a cleanroom in small boxes at one time and work successively on small modules in order to maintain operations. You can retrofit, turn that space over and work your way through a cleanroom in pieces.”
Key factors to a successful retrofit
Planning. Planning is the most vital part of a successful retrofit or upgrade, but amazingly, it can be overlooked or ignored. “Sometimes it is difficult to adequately plan because of time-to-market constraints, but you set yourself up for failure if you don`t,” says Anderson.
Lack of planning can lead to many problems, such as unscheduled shutdowns of process utilities by a contractor; unscheduled construction interruptions; vibration from heavy equipment and other types of construction tools interfering with operations; and even some simple things like blocking off egress, emergency exits and process flow.
As part of the planning process, Anderson advises getting a complete buy-in from production and engineering staffs, as well as from the outside contractors, as to the exact scope of work. The retrofit team then needs to meticulously plan how they will accommodate operations.
That involves identifying “your window of opportunity in the production schedule,” Loughran says. “Plan how you are going to segregate the area of retrofit from the operating area and how you are going to get materials and personnel in and out of the cleanroom, avoiding the construction area. And plan for your materials delivery to hit the window of opportunity.”
Other key planning concerns, according to Loughran, include:
demolition and disposal of hazardous materials, such as asbestos and items contaminated by process chemicals;
maintenance of fire exit corridors and sprinkler systems during renovation, which might require re-routing of piping systems, temporary disablement of sprinkler zones and temporary egress corridors; and
access for material, equipment and personnel to ensure that production workers can access operational areas and construction workers can access the construction site in a timely fashion.
Loughran says that temporary access corridors and gown rooms can make operations more efficient during the retrofit, saving production workers significant time entering and exiting the clean space. And separate construction entrances may seem to be a luxury during planning, but pay for themselves through more efficient production, he says.
Scheduling. Scheduling is one of the most important factors to success, especially since most of these projects are done on a fast-track. “I have never been involved in a cleanroom project that is not fast-track, where equipment is ordered before the design is complete,” says Anderson.
To initiate scheduling, Loughran advises developing a detailed schedule of work to be performed, which is then documented and incorporated into a preliminary schedule. The preliminary schedule is compared to the facility`s production requirements and any other factor that could require schedule flexibility.
In areas of schedule conflict, the project team must determine priorities and adapt requirements appropriately, according to Loughran. Consideration has to be given to squeezing or expanding the construction task`s duration to match schedules and maintain a cooperative interface. Overall project duration must be measured considering holiday schedules, manpower availability, man-loading within a confined work space and continued operation of the facility.
“What makes a project not work is if the schedule is not followed,” says Peterson. “If the schedule can`t be met, then costs are going to go up.” The schedule can be disrupted if the user changes requirements in the middle of design or construction.
Clearly defined scope of work. Critical to a successful retrofitting project is understanding exactly how you intend to use the room, says Dan Mahoney, vice president of JMC Environmental Systems (Concord, MA).
A common mistake is not to clearly define the scope of work and get agreement from all the parties involved — the facilities manager, end user and construction team, says Roxy Flanders, project manager for Brycon Corp. (Albuquerque, NM). Sometimes the user needs are not understood by the facilities manager, who may misinform the contractor on what is really desired. “You need to have the end user and contractor in the same meeting with the facilities manager. There should be no middle communication.”
Field investigation. Another common mistake in retrofitting is to rely on a previous set of drawings without verifying the current conditions. Basing a retrofit on outdated drawings can prove costly. A thorough field investigation should be conducted with drawings in hand to determine how closely the documented plans reflect actual conditions.
The field investigation will determine accurate structural conditions, piping, process piping and electrical routing. “You need to have knowledge of existing utilities and services that are in the area so when you start demolition, you don`t damage or interrupt facilities. You don`t want to interrupt the manufacturing process. It will also help the schedule move along much quicker,” Peterson says. Field investigation can remove unknown elements from the project, which can impact the schedule.
Identifying the level by which you can rely on the plans will significantly affect the aggressiveness of the schedule, material stock requirements and man-loading, Loughran says. At the same time as the field investigation, he also advises conducting a careful market survey to verify the availability of acceptable components that meet schedule and performance requirements.
Designing for flexibility. One of the biggest problems in retrofitting is designing for current requirements only and not designing for flexibility in the future. “An owner will give you a fab layout with tooling and you design everything to make that work. Six months down the road they want to change, and then you are retrofitting,” Peterson says.
For example, you could add an exhaust fan in the future, but the makeup air unit wouldn`t be able to handle the addition. Humidity requirements may not be flexible enough to handle future exhaust, or air conditioning capacity is too limited to accommodate increased tool layout density.
Designing for flexibility means anticipating what your requirements may be at a given point in the future. It is best to design the fab around benchmark requirements, adding the tools in later, Peterson says.
Flexibility is a key issue for Applied Magnetics “because the technology of manufacturing equipment changes so rapidly, we have to stay current,” Anderson say. “We eliminated or reduced major building columns within the fab area to allow free movement of wall panel systems. We used a series of below-grade trenches for some of our process utilities, while some of our areas have raised floors where we can be flexible with process utilities. If you`ve done your homework and designed the original fab and all the process utilities to maintain flexibility, it can make these changes, retrofits and expansions easier,” he says.
Storing materials. Storage space will be scarce during the construction process, so the project team should arrange for just-in-time delivery of new materials and components and provide for a staging area for materials, says Cline. “When you place the order, give suppliers an accurate deadline to meet, and follow-up to ensure they meet them.”
Proper provisions for material handling will significantly cut labor cost and the potential for contamination generation, says Loughran. Constant movement of materials puts them at risk to damage and can compromise a project`s completion.
When preparing for just-in-time delivery versus excess material stock, you should consider what and how much excess stock material is required, the associated premium costs and the critical nature of certain sequences along with lead time availability of potential quantity shortfalls, Loughran says. “Local sourcing of as many materials as possible must be considered in anticipation of a contingency response to unforeseen issues,” he says.
Protecting the existing environment. When renovation work begins, protocols must be established to ensure that contamination generation is kept to minimum, says Loughran. In areas where construction workers interface with operation production areas, the cleanroom protocol for construction must match the operating protocol, while balancing realistic protocol with cost and schedule considerations.
The construction area separation must be maintained at all times. The existing environment can be protected from damage or contamination by the proper use of clean partitioning materials. Attention should also be given to the areas above the ceiling, in duct systems, plenums, return walls, conduit and below the floor to ensure that any contamination spread from demolition is minimal and contained. When possible, equipment should be removed or isolated from the construction area, Loughran says.
During demolition, materials should be removed from the controlled area and properly disposed. Contamination-generating materials should be bagged and removed immediately from the critical environment. Personnel should be badged and identified as critical environment workers and non-critical environment workers. Products identified as salvageable and slated for reinstallation or re-use should be identified immediately upon removal to the staging area, cleaned and wrapped for storage.
With demolition complete, reinstallation of the salvaged materials and new material installation can begin. All materials should be treated as new and follow the incoming material protocol. Then, Loughran says, construction should occur under a build-clean protocol that equals or exceeds that of the operating facility.
Training and communication. Training is also critical to the success of a retrofit. Outside contractors and manufacturing personnel should be trained in internal cleanroom procedures and protocol during renovation work.
Constant communication with the manufacturing personnel is essential, Anderson says. Keep them updated on the schedule, planned interruptions, vibrations and noise. “Get buy-in from the manufacturing side on what you are doing and when you are going to do it, and they will be cooperative. Don`t surprise or blindside them. If they know it ahead of time, they can plan for it and keep operations as normal as possible.”
How to hold down retrofit costs
The biggest way to hold down costs is to keep to the schedule and know what you are designing for, Peterson says. “You will be able to keep costs under control if you have a clear understanding of the type of materials and lead times of those materials you anticipate using,” Anderson says. “You should also budget in a certain contingency for unforeseen conditions.”
Flanders suggests conducting a job walk-through with the construction lead to ensure everyone understands the scope of work. Do not allow changes after the start of the project without first meeting between teams to see what effect the changes will have on the schedule and cost.
Economical construction options may also help to hold down costs. For example, various grades of ceiling and wall systems are available. The less expensive systems aren`t as flexible as premium systems, and may require more support, but cost less per square foot. Cheaper-grade air handlers and filtration systems might also satisfy your requirements. Above all, don`t over-specify. “You don`t need to design Class 1-type equipment for a Class 1,000-type fab,” Peterson says.
Getting started
If you are new to retrofitting, JMC`s Mahoney advises getting professional help before spending too much time in-house wading through the issues. An experienced retrofitter can give you a primer on the basics, such as the cost associated with various cleanrooms, sizes and cleanliness classes, and information on Federal Standard 209E.
When selecting a contractor, choose someone who can best meet the lead time requirements, educational process and performance expectations.
And even though it may seem like you needed the work completed yesterday, “when you are retrofitting a cleanroom, faster isn`t always better,” Loughran warns.
“Realistically evaluate the timeframe in which you need to accomplish the work,” adds Mahoney. “Sometimes a customer wants to do in eight weeks a project that should take 14 weeks. This is an expensive product, and if you haven`t given sufficient time to the schedule, you are paying excess.” CR
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A Class 10 process lab at Bruce Technologies (Billerica, MA). Photo courtesy of JMC Environmental Systems (Concord, MA).
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Flat panel display systems are manufactured in Class 1,000 clean bays and Class 10,000 clean aisles at Brooks Automation (Chelmsford, MA). Photo courtesy of JMC Environmental Systems (Concord, MA).
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A phased retrofit project for clean manufacturing (Class 10,000) at Bruce Technologies (Billerica, MA). Photo courtesy of JMC Environmental Systems (Concord, MA).
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Cleanroom service aisle construction for a retrofit project at Applied Magnetics (Goleta, CA).
A case study
Converting office space into a Class 10,000 manufacturing plant taught Ray Cahoon one big lesson: Do not allow yourself to be oversold when planning a retrofit or upgrade.
“There are so many levels of cleanliness. It`s easy to be oversold with cleanliness that you don`t need or particle levels you don`t need,” he says. “Make sure the contractor understands what you are doing and understands your product. Contractors should be asking you questions about your process.”
Cahoon is the facilities manager at Tokyo Electron Massachusetts (Beverly, MA), a division of Tokyo Electron of Japan. The company manufactures oxide etchers used in semiconductor processing.
The Massachusetts division was operating as an R&D facility until two years ago when the parent company decided to begin manufacturing operations in the U.S. The company requires its Unity II etcher system to be built in a Class 10,000 or better environment.
The existing facility was a two-floor building with about 20,000 sq. ft. on each floor. “It`s not a building that lends itself to manufacturing,” Cahoon says. “It`s more of an office building. The low ceilings and floor loading capacity weren`t what they needed to be for manufacture.”
One of the first tasks the project team undertook was to demonstrate a 6,000 sq. ft., Class 10,000 cleanroom design on the upper floor. With a satisfactory design and budget in place, construction began.
To save on costs, the project team kept parts of the room in order to avoid a huge demolition job. “We ended up leaving some existing sheet rock walls, and we used special epoxy paint that does not outgas in a cleanroom. We were also able to keep intact the vinyl floor tile,” Cahoon says. “Everything else had to go.”
The typical office ceiling grid with foam tiles gave way to a unique plenum space design. The space between the ceiling and top of the roof is now used as a common air plenum with clean cool air. “It`s a much more efficient approach using that space above the ceiling as a common air return plenum, as opposed to individually ducted-fan HEPAs, which are noisy and consume considerable power,” Cahoon says. The existing HVAC system on the roof was replaced with a new, higher capacity model.
The second phase of the renovation required adding 10,000 sq. ft. of cleanroom space as a building addition, which will be attached to the upper-floor cleanroom. An elevator/lift system will be used to transport the process module manufactured on the upper floor to the new addition for final processing.
The lower cleanroom is also Class 10,000, with a Class 1,000 “shroud” around the etcher itself. Additional HEPA filters and a transparent curtain separate the two areas. There is also a small Class 100 area under construction, which will be used as an applications lab.
One wall divides the upper floor cleanroom, which is operational, from the construction area for the new addition. The wall will be taken down when the new cleanroom is complete this month.