Photolithography services create photomasks and use them to etch or engrave patterns on semiconductor substrates. Photolithography is a semiconductor manufacturing process that is used to remove parts of a thin-film selectively, or to etch away the majority of a flat substrate. Typically, this microfabrication process uses a photomask for integrated circuit (IC) fabrication. Photomasks are made of high-purity glass or quartz, and contain precise images of ICs or chips that are transferred optically onto semiconductor wafers. By using a powerful, projected light and a high-aperture lens, photolithography services cast an image of the device’s design onto a silicon wafer coated with a photoresist, a light-sensitive material that is then removed.
The photomasks that photolithography services use are optical templates that, depending upon the photoresist, represent a positive or negative image of the semiconductor design. With a negative photoresist, the masked part of the semiconductor substrate is removed. With a positive photoresist, the unmasked part is removed. In both cases, light is used to transfer the pattern from the photomask to the photoresist, which is on the semiconductor. Using chemical reactions, the pattern on the photoresist is etched into channels. Because many chips are manufactured in layers, photolithography services repeat these deposition and removal steps, each time with a different photomask. Some semiconductors have as many as 30 layers.
Applications, Capabilities and Certifications
Photolithography services differ in terms of applications, capabilities and certifications. Some companies serve the barcode, medical imaging, microscopy, or optical industries. Others specialize in robotics, scanning, or photonics applications. Supplier capabilities include photolithography services for two-dimensional (2D) and three-dimensional (3D) microstructures, chemical or photochemical etching, chemical milling, photo engraving, and photofabrication. Photolithography services that use spin coater workstations for the spin deposition f photoresist are also available. This technology, which develops and bakes in a single-wafer process, is used both for research and development (R&D) and for specialized semiconductor fabrication.
In terms of materials, photolithography services may work with a variety of substrates. Examples include aluminum, brass, bronze, beryllium copper, steel, carbon steel, lead, magnetic alloys, and molybdenum. Photolithography services that work with specialty or proprietary materials such as Monel and Inconel (Special Metals Corporation) are also available.