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The Role Of A Stepper In The Fabrication Of Integrated Circuits

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Integrated circuits are used in almost all of the appliances and electronic devices available on the consumer market. Manufacturing these integrated circuits requires a very precise approach. Specialized machines known as steppers (which is short for step-by-step) are used to help ensure precision and control throughout the manufacturing process.

Learn more about the role a stepper plays in the fabrication of integrated circuits that make daily life more convenient.

Silicon Disk Alignment

Integrated circuits start as small disks that are cut from a cylindrical crystal of semiconductor material. Each disk is placed into a holding chamber within the stepper. When the time to begin the fabrication process arrives, the stepper utilizes automated robots to move individual disks from the holding chamber to the processing plate.

The alignment of the silicon disk is critical since it will determine the efficacy of the finished integrated circuit. Steppers rely on highly sensitive equipment to identify, read, and align disks according to specific parameters.

Pattern Exposure

Once a disk has been properly aligned, a stepper will place a reticle over the top of the disk. The reticle contains both opaque and transparent areas that define the function of the integrated circuit. A stepper must ensure that both the disk and reticle are precisely aligned to create integrated circuits that will function properly once the fabrication process is complete. Some steppers have the ability to utilize multiple reticles that can be placed over a repositioned disk to help streamline the fabrication of larger integrated circuits.

Disk Development

In order to transfer the pattern contained on the reticle to the silicon disk, a unique chemical known as a photoresist must coat the surface of the disk itself. Photoresist is highly sensitive to ultraviolet light. The stepper utilizes an ultraviolet light that is projected through the reticle and onto the disk. The opaque areas of the reticle help to control the distribution of light, resulting in areas that are more developed than others.

After light exposure is complete, the coated silicon disk is rinsed with a developing agent that removes the photoresist in all areas that were exposed to the ultraviolet light. Acid is then used to etch these exposed areas, creating finished integrated circuits that are capable of performing a wide range of functions.

Steppers have revolutionized the way that integrated circuits are manufactured. Advancements in technology continue to contribute to the development of more powerful and precise steppers capable of creating microscopic integrated circuits for today's electronics.

To learn more about integrated circuits, such as Ultratech Saturns, reach out to a local supplier.