Integrated circuits
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This document provides an overview of integrated circuits (ICs), including a brief history from their invention in 1958, the scale of integration from small to ultra-large scale, the wafer fabrication process involving shaping, etching, cleaning and film deposition, the advantages of ICs being small, light and fast, and their applications in computers, automobiles and more.
Integrated circuits
- 2. Introduction Brief history Scale of integration Types of IC’s Wafer fabrication process IC’s fabrication techniques Advantages Disadvantages Applications Conclusion References
- 4. 1940’S – Initial stage. 1945’s – Bell labs established a group to develop a semiconductor replacement for vacuum tubes. 1947’s – Transistor invented. 1951’s – Junction transistors invented. 1958’s – Integrated circuits invented.
- 5. Small scale integration (SSI) Medium scale integration (MSI) Large scale integration (LSI) Very large scale integration (VLSI) Ultra large scale integration (ULSI)
- 6. Wafer scale integration (WSI) System on a chip (SOC) 3D IC’s
- 7. Analog IC’s Digital IC’s Mixed signal IC’s
- 8. Silicon shaping: Removal of ends Surface grinding Grounding of flats Slicing of ingots Lapping Edge contouring Chemical etching Polishing Chemical cleaning
- 9. Silicon is a hard & brittle material. Industrial grade diamond is the most suitable material for shaping & cutting silicon.
- 10. Remove seeds and tang ends. Metallurgical grade silicon (MGS). Cutting is done using a circular saw.
- 11. Rotating diamond grinding tool. X-ray diffraction techniques.
- 12. Primary flats Secondary flats
- 13. Inner diameter sawing Diamond saw
- 14. The wafer flatness produced at this step is better than 2 micro meter. Mixture of AL2O3 & glycerin.
- 15. Diamond tool. Prevents defects. Helps in smooth deposition of photoresist.
- 16. Acid etching: • acid bath • etchant Alkali etching: mixture of NaOH:H2O or KOH:H2O
- 17. For smooth surface Batch wafer process Single wafer process Slurry
- 18. Silicon wafers are cleaned chemically to remove organic films, heavy metals Aqueous solution of NH4OH-H2O2, HCL- H2O2.
- 19. Diffusion and ion implantation Oxidation and film deposition Epitaxial growth Lithography Etching Photo resist Deposition
- 21. Oxides are grown or deposited on the surface of the wafer Film deposition: thermal oxides dielectric layers polycrystalline oxides metal films
- 22. The growth of ultra pure layer of crystalline silicon. Approx 3% of silicon wafer. Contaminate free for the subsequent construction of transistor.
- 24. Small size Low weight Easy replacement High speed High temperature tolerance
- 25. Lack of flexibility High power requirements
- 26. Automobiles Appliances computers
- 27. Modern computing, communication, manufacturing and transport system including the internet, all depends on the existence of integrated circuits.