Polyimide Ovens

Polyimide oven solutions we carry

What is a polyimide oven?

A polyimide oven is a high-temperature vacuum machine that uses nitrogen flow cycles, a programmed vacuum, and a programmable temperature controller to cure polyimide coatings/ films.

The unit comprises a filtered, heated nitrogen purging unit that covers the entire roof surface to the floor of its chamber. The flow serves to clean the wafers in the process. A Polyimide oven uses an electrically heated oven designed to serve the specific heating process needed for tricky baking polyimide coatings while in a vacuum/ inert atmosphere.

A high-performance and clean process oven features a 100 recirculated unit airflow. It has many unique components, such as an oxygen control system and pressure relief system, ensuring strict atmospheric and oxygen requirements during polyimide curing.

Components of a Polyimide oven System

Pressure Relief System

The entire residual solvent is extracted during the hard baking polyimide curing process, followed by finalizing the desired surface properties. The extraction process demands that the oven is heated to prevent and correct any form of solvent condensation.

These polyimide oven dispatch designs feature a pressure relief system with a controllable “cold trap,” i.e., a cleanable condensate trap that prevents polyimide buildup in the exhaust system of the polyimide oven.

Oxygen Control and Monitor System

These Polyimide Ovens include an inert atmosphere oven that helps regulate the oxygen levels to ensure it is maintained at 20 ppm or below. The purpose of this is to prevent oxidation of the cured polyimide.

The oven also features an Oxygen monitor, which is purposely connected to the purge valve. The purge valve helps turn on the nitrogen purge valve when the oxygen level exceeds the maximum Oxygen monitor value.

The ideal O2 levels are maintained in the chamber after completing the nitrogen purge. This ensures minimum nitrogen usage and also ensures repeatable and consistent product curing.

Product Monitoring System

These Polyimide Ovens feature PC control software that helps communicate between the oven and the PC. For example, it has an Ethernet connection port of 38.1cm (15in) and a flat panel screen for explicit display purposes.

The Protocol software communicates with the Oven Control system, i.e., O2 monitors, to help observe data log cycles and provide the user with accurate real-time information, actual O2 levels, and chamber temperatures through the curing process.

Basic Features

• A compact cabinet design for minimizing footprint.
• The interior surface is continuously welded on a solid insulation side to ensure that the work chamber is protected from contamination.
• The heat loss in the chamber is minimized by the 4 in thick insulating material, external thermal spots, and air leakage.
• The recirculation air undergoes 100% filtration through the help of 99.99% HEPA filters to ensure better operation.
• The Magnehelic gauge HEPA filter pressure helps indicate when to replace the filter Protocol control with an integrated data logging port, LCD, and a USB port to ensure simple and more accessible data export and oven set up.
• Silicone-free construction
• High-limit audible, end cycle, and visual alarms to notify the operator when to stop a process
• Electronic and programmable door lock
• Burn-off and Installation of HEPA filter includes a post-burn-off residual cleaning from the chamber.

The cold trap is removable and easy to clean condensate trap that prevents any polyimide buildup in the exhaust system of the oven.

How does polyimide curing work?

Polyimide cure process and requirements. Typically, polyimide cure temperature can range from 280 to 400 °C based on the application and the material used.

Generally, a nitrogen atmosphere is together with oxygen content ideally below 100 PPM. Reasonable temperature and uniformity should be maintained for uniform heating of the wafer.

Higher exhaust rates are maintained to ensure no fume build-up. Fast-cycle times ensure better performance throughout the entire process.

What happens during the curing process?

During this process, an adhesive polymer or/and a cross-link undergoes a phase change, i.e., a change in the matter state from liquid to solid matter state.

Parameters that affect the material physical properties during the oven-curing process

• Type of the oven loading mechanism
• The cooling and heating ramp rates
• The variation if exhaust gas flow rate
• The temperature variability within the oven i.de is temperature uniformity maintained
• The Oxygen levels inside the oven, i.e., the ideal, should be 100 PPM and below
• Atmosphere cleanliness ISO 5/ Class 100 or better
• The variation in temperature control set temperature vs. the actual oven temperature.

How do the differences in an oven loading capacity affect the curing profile?

Generally, a heavier loaded oven requires a longer ramp-up for the fully curing process than a lightly loaded oven. In the same way, a heavier loaded oven will take longer to cool, i.e., cool slowly. The variability in cured material properties also results from the variation of the ramp rates

Polyimide bake oven uses and applications

Polyimides are engineered polymers with high temperatures and excellent mechanical and electrical properties. Most Microelectronic applications of these polymers include passivation layer, stress buffers, interlayer dielectric, and chip bonding.

Polyimides are applied in liquid form; then, a polyimide bake oven is used to thermally cure the liquid polyimide into a layer or film with the ideal properties.

The Formulated polyimide liquid requires curation in a furnace, i.e., a polyimide bake oven that has regulated temperature and oxygen to ensure uniformity, thus preventing crack formation or color variations. For example, low oxygen values are needed to ensure bright material with good adhesion properties is formed.

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