Foturan

Foturan is a photosensitive glass ceramic material developed by Schott AG. It is characterized by its ability to be selectively crystallized by exposure to UV light. This unique property allows for the creation of complex three-dimensional structures within the material through a photolithographic process.

Properties and Process:

Foturan starts as a transparent glass. Areas exposed to UV light undergo a chemical change, creating latent images of the desired structure. These exposed areas then undergo a controlled heat treatment, which causes crystalline phases to nucleate and grow only in the irradiated regions. The remaining, non-irradiated glass remains amorphous.

After the heat treatment, the uncrystallized glass can be selectively etched away using hydrofluoric acid (HF). This etching process leaves behind the crystalline structures created by the UV exposure and subsequent heat treatment, resulting in highly detailed and intricate three-dimensional microstructures.

Applications:

Foturan is used in a variety of applications, including:

• Microfluidics: Its ability to be precisely patterned makes it suitable for creating microchannels and other components in microfluidic devices.
• Micromechanics: Foturan can be used to create small mechanical components and sensors.
• Optical Components: The material's optical properties and ability to be shaped into complex forms make it useful for creating lenses, waveguides, and other optical elements.
• Biomedical Devices: The biocompatibility and precision fabrication capabilities allow for its use in certain biomedical applications.
• Mask Making: Foturan is utilized as a substrate for manufacturing photomasks used in semiconductor fabrication.

Advantages:

• High Precision: Foturan allows for the creation of structures with very fine details and tight tolerances.
• Three-Dimensional Structuring: Complex 3D shapes can be created through the selective crystallization and etching process.
• Chemical Resistance: The crystallized material is resistant to many chemicals, including acids (except HF).
• Optical Transparency: In its glass state, Foturan is transparent, allowing for its use in optical applications.
• Biocompatibility: The material exhibits biocompatibility making it suitable for medical uses.

Limitations:

• Etching Process: The etching process uses hydrofluoric acid, which is a hazardous chemical that requires special handling and safety precautions.
• Material Cost: Foturan can be more expensive than other materials used for similar applications.
• Process Complexity: The fabrication process involves multiple steps, including UV exposure, heat treatment, and etching, which can be complex and time-consuming.