PELLICLE AND PHOTOMASK ASSEMBLY

Smart overview of the Invention

The invention pertains to a pellicle and photomask assembly used in lithography processes for wafer manufacturing. The assembly is designed to protect the photomask from contamination or deformation caused by environmental factors. At the core of this assembly is a pellicle membrane made from carbon nanotubes, known for their strength and high transmittance, supported by a frame that directly contacts the membrane's edges.

Functionality

The pellicle serves as a protective layer over the photomask during lithography, preventing defects on the wafer. The carbon nanotube membrane is designed to be free-standing on the frame, minimizing stress and deformation. The frame is engineered to provide a stable support structure, ensuring the pellicle maintains its integrity during the lithography process.

Design Details

The pellicle membrane is extremely thin, allowing for high light transmittance, crucial for effective photolithography. It is composed of a carbon nanotube layer, with thickness ranging from 5 nm to 20 nm, and achieves transmittance rates of 90% or more. The frame, which supports this membrane, is directly connected to its peripheral edge and can be configured in various shapes, such as quadrangular or circular forms.

Material Composition

The frame is made from materials that offer excellent heat resistance, including metals like aluminum, zinc, and stainless steel, or materials like diamond-like carbon and silicon. The bonding between the frame and the photomask is facilitated by an adhesive layer, which can include viscoelastic or hot melt adhesives, tailored to withstand the specific environmental conditions of the lithography process.

Assembly Integration

This assembly integrates the pellicle and photomask to form a closed space that protects the photomask from external contaminants. The adhesive layer ensures a secure bond between the frame and the photomask, enhancing the assembly's durability and reliability during use. This design supports mass production by simplifying the assembly process and reducing the need for additional connecting means.