STACIS Quiet Island

Semiconductor manufacturing factories (fabs), Nanotechnology Centers, Nanofabs, and other precision manufacturing and research facilities often incorporate cleanrooms with a system of raised false floors to accommodate complex facilities requirements (plumbing, electrical cables, gas piping, etc.) and to maintain strict cleanliness standards. Such floors present a challenge to the installation of vibration-sensitive production, inspection, and metrology equipment. The raised floors cannot provide the necessary quiet vibration environment for such tools. TMC's Quiet Island^® is an innovative solution that replaces a section of the raised floor area with a "Quiet Island" anchored to the sub-floor below. The Quiet Island consists of a cleanroom compatible platform top combined with an application and site specific support structure.

Vibration Cancellation

The main support element and core technology unique to the Quiet Island is the STACIS III Active Vibration Cancellation System. This "rigid" style inertial vibration cancellation support system is critical for any vibration sensitive instrument, enabling such tools to operate to their highest standards in an otherwise noisy environment. STACIS III is compatible with automated wafer processing tools, high resolution eBeam imaging tools, ion-beam milling tools, and any tool with internal vibration isolation systems, both passive and active (see our white paper on stacking active on active isolators). In addition, it provides the most vibration isolation across the widest frequency range commercially available. And, the "hard-mount" design is extremely stiff so that there is no stability concern for tall, top-heavy tools.

For very short raised floors, a more compact version of the Quiet Island can be designed utilizing STACIS IIIc isolators.

Risers and Supports

Extremely rigid and durable risers to support STACIS isolators are designed by TMC's experienced engineering team and manufactured to high standards and welding certifications in our ISO 9001 factory. Each Quiet Island is engineered to suit a variety of raised floor heights, sub-floor geometries, and tool footprints. With thousands of installations globally supporting over 200 different instrument models, TMC has the knowledge and experience to design a support structure meeting the needs of STACIS and your facility.

Rigid Platform

The raised floor platform is a TMC designed and manufactured 4 inch (100 mm) thick lamination of steel plates sandwiched around a lightweight, incompressible, damped core material. The layering effect of rigid steel plates and core, epoxy bonded into a seamless, stainless steel pan provides an extremely high level of stiffness and structural damping. The large cross-section and steel content yield a very high level of overall rigidity. The top and sides are a continuous, one-piece, stainless steel shell to preserve cleanliness, appearance and integrity. TMC designs and manufactures the platforms specific to the application incorporating cutouts, special shapes, tiedown holes, and lifting bolts as required.

Designing a facility to meet the stringent Vibration Criteria of extremely precise imaging equipment can be very challenging, and often cost-prohibitive, particularly when not all tools in the facility require these very low vibration levels.^[1]

Statistical representation (in terms of Mean plus Sigma Spectra) of vertical vibrations in a typical semiconductor fab production area at "as built" and two times thereafter ^[2]

It is very difficult to isolate very large areas such as entire buildings, or an entire floor. It is also well documented that building vibration levels will increase relative to a design specification as the facility is populated with equipment and people. Repeated vibration measurements a few months, or a year later, show that floor vibration levels typically rise over time.^[2]

The more cost effective and successful approach for achieving the stringent requirements of vibration sensitive tools, is to employ point-of use active vibration control with serial piezoelectric technology, particularly to mitigate challenging low frequency (less than 5 Hz) vibration (example here).

TMC can work with the your team to design a tool-specific Quiet Island solution. This process allows us to look at each tool specifically and provide the best performing solution. A building design incorporating one large concrete sub-floor “slab” with a “raised floor” allows for flexibility of tool selection post-construction. Replacing the raised floor with a Quiet Island only where needed provides the most sensitive tool set with a vibration environment an order of magnitude, at least, lower than the sub-floor.

See also The Benefits of Including Floor Vibration Control for Nano-Tech Facilities over Designing "Quiet" Buildings article on AZO Nano.

¹Evolving criteria for research facilities: I – Vibration, Colin Gordon Associates, SPIE Conference 5933: Buildings for Nanoscale Research and Beyond, 2005, Source

²Maturation of the Vibration Environment in Advanced Technology Facilities, Colin Gordon Associates, Journal of the IEST, V. 48, No. 1, 2005, Source

• Incorporates STACIS - TMC's active piezoelectric vibration cancellation technology is unmatched in the industry, with its "hard mount" design and isolation starting at 0.6 Hz, compatible with tools incorporating internal isolators.
• Modularity, customization and relocation flexibility - Each platform is individually tailored to the customer's application but can easily be reconfigured if the tool or the floor characteristics change, unlike concrete plinths.
• Expertise - TMC has broad experience working with the world's leading semiconductor manufacturers, scientific facilities and ultra-precision OEMs. We know our customers and their needs. We design and manufacture in-house.

Measured transmissibility on a 24” tall 40”x60” Quiet Island, 4-mount STACIS support, VC-C input from the floor

For vibration isolation specification see STACIS® III.

Large instruments without a vibration specification for the environment very often require a rigid and stable support separated from the raised floor. The Rigid Quiet Island is the ideal solution. With the same high performance platform top, Rigid Quiet Islands are also custom engineered for installations in raised floor cleanrooms with any height, any sub-floor geometry and for a variety of tool footprints. TMC offers a range of different types of support posts to accommodate a range of requirements, resulting in a solution specific to the instrument and Fab, yet is modular, provides flexibility to relocate, and is upgradable.

Because of the complexity, sensitivity, and value of the equipment installed on our Quiet Island® Sub-Floor Platforms, we do not maintain standard catalog numbers for ordering. We consider each installation to be a custom-engineered solution. The recommended procedure for ordering is as follows:

• Tell us what equipment or instrument you want to isolate. Because of our installed base, it is likely that we have already engineered a platform design to the requirements of your application. In addition, we maintain close contact with stepper, aligner, SEM, and other tool manufacturers to keep current with size, shape, weight changes, and floor vibration specifications.
• Alternatively, you may want a system to fit within the raised floor grid system. Specifiers often opt for a 47 x 47 in. (1,190 x 1,190 mm) platform to replace an even number of floor tiles.
• Tell us the height of your raised floor above the solid sub-floor.
• Describe to us or provide an illustration showing any hole pattern in your sub-floor or the steel beam/waffle slab geometry.
• Provide us with floor vibration data or discuss with us how to arrange to have this data measured.
• Consider the vibration sensitivity of the instrument. Many tools are adequately supported by our rigid, non-resonant post design. More sensitive applications will require air or piezo support