1. Introduction to Silicon Processing Dr Vinod V. Thomas SMIEEE Ref: Section 2.2 ASICs : MJS Smith

2. Integrated circuits What are Silicon ICs ? Invented ? –1958/59 –Kilby at TI, Noyce at Fairchild –Complexity ? –Minimum feature size –Wafer size –Chip size

3. Why Silicon ? Abundance Semiconductor Easily grown oxide Relatively large band-gap (1.1 eV)

4. Levels of integration SSI – 10s of Tr MSI – 100s LSI – 1000s VLSI > 10K ULSI GSI

5. Overview of Si processing Selective addition and removal of material to/from substrate Controlled by lithography –Series of masks define location of features Doping –Boron or phosphorous added by diffusion or ion implantation to modify conductivity Oxidation –SiO 2 grown – insulation, masking, protection Metallisation –Deposit metal layer for interconnection Packaging –Place in a package and bond connecting wires

6. Si processing… Si refined from Quartzite –(purity < 1 inpurity in 10 10 atoms) Drawn as a single crystel Si @ 1500 °C –Boule OR Ingot –Czochralski Growth Sawn to form thin Circular Wafers –8” or 12” Diameter; 600  m thick

7. Si processing… Chip size –4.2 mm 2 die –18 k die/ Wafer –1 k Wafer/day Technology –Feature size: Production 90 nm; 65 nm

8. Benefits of integration Size Reliability Security Cost Performance