vlsi chip making singular feature

PRESENTED BY:

Y.L.REVATHIV.HARSHA SRI

ABSTRACT

INTRODUCTION

FRONT END CONSTRUCTION OF COMPONENTS

BACK END – ADDING THE CONNECTING WIRES ADVANTAGES OF SINGLE FEATURE OVER BATCH PROCESS

CONCLUSION

VLSI – Very Large Scale Integration(10^5 -10^7)

VLSI design started in 1978. Today one of these 300-mm wafers can yield more than 700 Ics

Early process is the batch process where there is over production of chips.

In this paper the IC fabrication steps are given in brief. Batch process and the Single wafer process are compared in detail

Batch process

Singular process

Now 300mm wafers can yield more than 700 Ics.

ICs are manufactured with one wafer at a time process(Singular process) ) rather than many wafers at a time process(Batch Process)

Chip production today in detail

The number of transistors per chip will double for every 18 months

Steps for making components of the chip:

Construction Plan

Mask with circuit patterns

pure silicon crystal is grown

cutting and polishing

Covering with layer of silicon oxide

Placing protective material

Passing UV light

Etching

Doping

Steps for adding metal and connecting components

Metallization

Adding photo resist

Adding mask layer

Removing photo resist

Removing metal

Need of metal layer for connections

Testing

Separating chips from wafer

More good chips

Equipment is smaller

Uniform properties to all Ics

Maintains thickness of SiO2

Economically advantageous

Costs less

Hence single wafer process is adopted rather than batch process. IC manufacturers can plan their production very well with single wafer process.