|Other Names||thermal treatment, baking, soft baking|
|Equipment||List of curing equipment|
|Materials||Polymeric thin films like, spin on glass, polyimide, photoresist, sol-gel etc.|
|Warning:||This page has not been released yet.|
Curing is often referred to process in which a thin polymeric, or slurry are exposed to a determined process in order to remove solvent and activate cross-linking reactions that will toughen and hardened the material to make it durable and stable. The curing can be done by temperature or UV exposure. One such proccess is the sol-gel curing, the slurry (mix of solid and solvent) curing and polymer curing. There are several widely used polymers in the semiconductor (micro-nanofabrication) industry: photoresist, polyimide and Spin on Glass (SOG) to name a few. In this section we will refer to temperature curing, as the UV curing is covered under lithography and nanoimprinting.
Method of operation
In all cases mentioned both the thermal and UV curing process are very specific. Thermal curing is done in a controlled environment (i.e. vacuum or reducing atmosphere) and under controlled conditions which are often referred as the heating program. Hence qualified equipment is needed where the environment, heating rate, cooling rate in addition to the ability to program the temperature vs. time changes are needed.
This is commonly used to cure spin on glass, poly-imide, photoresist. In addition sol-gels must be cured and slurries containing materials that will be deposited by spinning to obtain a film with a desired composition and thickness.
Polyimides are used, as packaging material, in electronics as a low k dielectric,as planarizer in interconnect to fill in cavities with an stable insulator. It is also used as waveguides, as durable, flexible substrate, as nanoparticles, as TAB interconnect in flip chip, etc.
Spin on Glass are used as dielectric fillers, planarizers, etc., SOG's are stable, planarizable, can be etched, etc. They are preferable used in situation where other silicon oxide deposition are not possible. They come in a variety of viscosities (thicknesses) and there are several suppliers.
Sol-gel is a fabrication technique mainly used to make oxide ceramics, or polymer-ceramic composite materials. These materials can be in the form of powders, coatings, bulk monoliths or fibres. The two most common (i.e. economically viable) being powders and coatings. They are also used in micro and nano-fabrication in cases where the components of the films can't be stoichiommetrically deposited, or when segregation rules does not allow these compounds in commonly used tools, as in the case of Li compounds, or when low cost approach to fabrication is needed
The two most important parameters are temperature program and environment
The temperature program is crucial to obtain a uniform film, stable, avoid crack formation, avoid bubble formation, etc.
The curing can be done in oxidative environment, when the formation of certain oxides is desired, a reducing environment, when the oxide formation needs to be avoided, vacuum environment, nitrogen atmosphere, etc.