Specifications.pdf

SPECIFICATIONS

Polyimide Curing Oven

BACKGROUND:

The Boulder Microfabrication Facility (BMF) is an 18,000 square feet Class 100 cleanroom located in the Katharine Blodgett Gebbie Laboratory. It is operated by the MicroFabrication Group in the Quantum Electromagnetics Division of the Physical Measurement Laboratory, who is responsible for providing the NIST-Boulder staff with state-of-the-art microelectronic and microelectromechanical systems (MEMS) fabrication capability.

PURPOSE:

The BMF requires a polyimide curing oven for use in developing new wafers processes. This oven will be used to cure photo-definable polyimide films after deposition on silicon wafers. In a typical process polyimide precursor is applied to a wafer using existing spin coating equipment. The wafer is then soft-baked using existing vented vacuum hot plates at temperature near 120ºC. The wafer is then exposed to ultraviolet (UV)light in an existing wafer stepper and developed using tetramethylammonium hydroxide (TMAH) in an existing puddle development tool. After these steps the polyimide film is cured by baking it in a N2 atmosphere. During the bake, the temperature of the oven undergoes a thermal profile that typically consists of a controlled ramp to an intermediate temperature (roughly 200ºC) where it is held for 30 minute.

The temperature is then ramped again to the final cure temperature (350ºC) where it is held for an hour or more. The temperature is then ramped slowly to ambient, and the wafers are removed from the oven.

There are two variants in oven design that are envisioned to be proposed – HEPA filtered N2 atmospheric-pressure ovens and HEPA filtered N2 vacuum ovens. Either variant is acceptable.

SPECIFIC REQUIREMENTS

1 each Polyimide Curing Oven

TECHNICAL SPECIFICATIONS:

The system should be a production model, not a prototype or one-of-a-kind system. There shall be at least 5 working units of the proposed make and model operating currently in the field. All equipment (excluding the possibly proposed vacuum pump) shall be Class 100 cleanroom compatible, designed to sit entirely within a cleanroom. The proposal package should include the mechanical hook up requirement listing all required utilities (power – voltage and current, N2 - flow and pressure, exhaust – flow and pressure, cooling water – flow and pressure).

Operating Temperature: From less than 40ºC to at least 350ºC.

Operating Temperature Uniformity at 350ºC: Less than ±5ºC variation.

Operating Temperature Stability at 350ºC: Less than ±4ºC variation.

Temperature Ramping: The ramp rate between temperatures must be controllable. We require a ramp rate of at least 5ºC/minute for heating from ambient to 200ºC, and a ramp rate of at least 3ºC/minute for heating from 200ºC to 350ºC.

Temperature Programmability: It is required that the oven have some means of programming an entire cure cycle consisting of at least a ramp at a controlled rate followed by a timed hold at one temperature followed by a second controlled ramp and an additional time hold. The cycle must end with a controlled ramp to ambient temperature. The oven must provide some indication of the current status of the cycle and current temperature.

Atmosphere: The oven must be operated with a N2 atmosphere utilizing flow through the oven.

The N2 atmosphere must be filtered using a HEPA filter to maintain an interior cleanliness of ISO 5 (class 100) or better. The oven shall be capable of obtaining O2 concentrations of 100 ppm or better.

Oxygen Concentration Monitoring: Atmospheric ovens are required to have instrumentation to monitor the O2 concentration throughout operation. This monitoring is needed to determine when the O2 concentration is low enough to start the thermal process.

Volume: The capacity to processing at least one standard 25 wafer cassette of 150 mm silicon wafers. Because of the value of space in our cleanroom, ovens with smaller footprints that meet this specification are preferred to larger ovens.

Footprint: No larger than 1.2 m x 1.2m (48 inches x 48 inches).

Oven Stand: If the proposed oven is not designed to sit on the floor, it is required that an appropriate stand be provided.

DELIVERY: 12 Weeks ARO or sooner

TYPE OF CONTRACT:

Firm Fixed Price