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21 Cards in this Set
- Front
- Back
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What is an oxide (typically SiO2?)
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These materials used in IC fabrication insulate transistors gates (gate oxide) or act as insulation between metal layers (ILD.) They are either chemically deposited or thermally grown.
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What is Moore's Law?
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This law states that the number of transistors in an IC doubles every 1.5 years.
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What are advantages of small transistors?
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These advantages are increased speed, lower cost per die, less power consumption and more devices integrated on a single chip.
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What is a clean room environment?
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This environment is necessary for the fabrication of integrated circuits. In it air is continuously filtered and recirculated to keep dust to a minimun.
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What are processes that change the Si wafer surface?
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These thermal processes are oxidation, diffusion, ion implantation and annealing and epitaxial deposition.
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What is photolithography?
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This process is very key in IC manufacturing. It uses light to change the solubility of a film (photorsesist,) which can then be developed to create an image. UV light with a wavelenth of 248nm is commonly used.
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What is a photoresist coating?
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This material is applied to a wafer using spin coating. Its thickness is affected by spin speed, spin time and viscosity of the photo resist.
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What are steps of photolithography?
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These steps are deposition of material, coating with photoresist, exposure, development, etching (material) and stripping photoresist.
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What is negative photoresist?
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This coating prints a pattern that is opposite of the pattern that is on the mask.
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sand
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From what is silicon extracted?
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What is the process for creating silicon wafers?
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Silicon extracted from common sand is chemically reduced and purified. Then silicon ingots are grown from molten silicon. Single crystall ingo is grounded down to a desired diameter (ranging from 1 to 12 inches.) Silicon wafers are sliced off and polished.
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What is ingot pulling?
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This action occurs when a seed crystal is suspended in molten bath of silicon and slowly pulled.
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What is polysilicon (polycrystalline silicon?)
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This chemically deposited material is key for transistor gates in IC fabrication.
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What is metallization material (Al, W, Ti, Pt, Cu?)
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This material used in IC fabrication is used as interconnections. Typically multiples layers of it are deposited using CVD, evaporation or sputtering.
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salt, smoke, dust
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What are examples of things that can destroy an entire IC?
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What are methods for maintaining a clean room environment?
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These methods include wearing bunny suits with face masks, walking through air showers, walking across sticky mats and wearing double gloves washed in DI water. The extent of these method depend on the classification.
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What are IC fabrication processes?
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These processes include changing the silicon wafer surface (thermal,) patterning SiO2, Si3N4, polysilicon or aluminum (photolithography.)
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What is microlithography?
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This technique is used to print ultra-miniature patterns with light, e-beams or x-rays.
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What is positive photoresist?
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This coating prints a pattern that is the same as the pattern on the mask.
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What are the post-fabrication steps?
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In these steps, each die on a wafer is electrically tested using an autoprober (bad die are inked.) The wafer is then sliced, and bad die are removed. Good die are wire bonded in packages and sealed. Completed devices are tested prior to shipment.
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tin whiskers
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What is one of the problems with using tin solder?
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