Which of the following statement is true for projection mode of lithography?
As effect of diffraction of light is more, it requires highly optimized optical system for projection
The optical image of a mask can be scaled down maximum up to 2X to 3X by depending on the mask
As, resolution of this system is limited by diffraction of light, the commercial systems cannot provide better resolution than contact lithography
All of these
To determine which statement is true for the projection mode of lithography, we need to evaluate each statement individually.
1. "As the effect of diffraction of light is more, it requires a highly optimized optical system for projection": This statement is true. Diffraction of light is a phenomenon that occurs when light waves encounter obstacles or pass through small openings, causing the light to spread out or bend. In projection lithography, diffraction can impact the fidelity of the projected image, leading to reduced resolution. To mitigate this effect, a highly optimized optical system is necessary to control and minimize diffraction.
2. "The optical image of a mask can be scaled down maximum up to 2X to 3X depending on the mask": This statement is false. In projection lithography, the optical image of a mask is typically scaled down significantly more than 2X to 3X. The exact scaling factor depends on the specific design and process requirements, but it can be much higher, often ranging from 10X to 100X or more. This scaling allows for the reduction of the mask pattern onto the target substrate with high precision and resolution.
3. "As the resolution of this system is limited by the diffraction of light, commercial systems cannot provide better resolution than contact lithography": This statement is false. While diffraction of light does limit the resolution of a lithography system, projection lithography can achieve higher resolutions compared to contact lithography. Contact lithography involves direct contact between the mask and the substrate, which limits the achievable resolution due to various factors, including the gap distance and the size of the mask features. Projection lithography, on the other hand, uses an optical system to project the mask pattern onto the substrate, enabling higher resolutions by reducing the effects of the contact-based limitations.
Therefore, the correct statement is: "As the effect of diffraction of light is more, it requires a highly optimized optical system for projection."