Projection Printing
Similar to film photography, by pressing the shutter button, light is projected onto the film through the lens and exposed. Afterwards, the image is obtained by soaking the film in a developing solution through "photo washing". Projection lithography is the mainstream lithography technology for integrated circuits due to its high efficiency and non-destructive advantages.
3a. Scanning Project Printing
Research began in the late 1970s and early 1980s. The size of the mask and pattern in this lithography machine is 1:1, which means that the size on the mask is the same as the size of the pattern on the photoresist. The reason why it is called scanning is because light is transmitted through a narrow slit onto the substrate, usually exposing several lines at once. The substrate needs to be moved to expose all areas with light energy.
Features: Process nodes range from 180 nm to 130 nm, mask plate ratio of 1:1, full-size exposure.
3b. Stepping repeating project printing (also known as Stepper)
Research began in the late 1980s and 1990s, using a lens system to project patterns from a mask onto a substrate one by one over a small area. After each exposure of a small area, the substrate will move to the next position until the entire substrate is exposed. An exposed area is a 'shot'. Because it is projected through a lens system, a 5-fold plate is generally used when using 365nm ultraviolet light, which means that the size of the pattern on the mask plate is 5 times the size of the actual photoresist. Therefore, more complex patterns can be designed on the mask plate, but it increases the difficulty of manufacturing the prism system.
3c. Scanning Step Project Printing (also known as Scanner)
Since the late 1990s, this type of machine is generally used in high-end semiconductor manufacturing for processes with a diameter of ≤ 0.18 μ m. During the exposure process, the mask moves in one direction while the wafer moves synchronously in a direction perpendicular to it.
Features: Increased field of view for each exposure; Provide compensation for uneven surface of silicon wafers; Improve the size uniformity of the entire silicon wafer. However, due to the need for reverse motion, the precision requirements of the mechanical system are increased. Scanners usually have higher production efficiency than other exposure machines, and their design and manufacturing are very complex. The purchase and maintenance costs of scanners are also high.
High precision double-sided lithography
Mainly used for the research and production of small and medium-sized integrated circuits, semiconductor components, optoelectronic devices, surface acoustic wave devices, thin film circuits, and power electronic devices.
The double-sided lithography machine includes a motion control system, an image processing system, system software, and a data I/O processing control unit.
High precision single-sided lithography
A high-precision lithography machine developed for various colleges, universities, enterprises, and research institutions based on the characteristics of lithography machine usage. It is used for the research and production of small and medium-sized integrated circuits, semiconductor components, optoelectronic devices, and surface acoustic wave devices.
It consists of a high-precision alignment worktable, a binocular separated field of view CCD microscopic display system, an exposure head, a pneumatic system, a vacuum pipeline system, a direct connected oil-free vacuum pump, an anti vibration worktable, and an accessory box.
Resolve the issue of misalignment caused by the inability to separate the plates due to non-circular substrates, fragments, and uneven substrate surfaces.
