8.1 Chapter 6. ic fabrication technology from 60s to date_part 1

CONTENTS

• Introduction.
• Two Broad Categories of I.C.
• Planar Fabrication Processes.
  • Epitaxial Diffusion Process.
  • Mounting on header and packaging.
  • Photolithography.
• Fabrication of MC 1530.
  • Preparation of single crystal silicon wafer.
  • Thermal Oxidation.
  • Technology of LOCOS.
  • Wet etching vis-à-vis dry etching.
  • Poly-Si buffered LOCOS.
  • Buried Layer Diffusion.
  • Passivation.
  • Solid State Diffusion.
    • Constant Source Diffusion.
    • Limited Source Diffusion.
    • Diffusion Systems.
    • Buried Layer Diffusion.
  • N epitaxial layer growth on P substrate.
    • Epitaxial Layer Growth by Chemical Vapour Deposition(CVD).
  • P type Isolation Diffusion for electrical isolation of IC components.
  • P type Base diffusion.
  • N+ diffusion for Emitter and Collector Contact.
  • Aluminum Contact Pads and Aluminum Interconnections of IC components.
  • Flow-Chart of the processing of MC-1530

Chpater 6. Integrated Circuit Design and Fabrication Technology

Section (6.1) Introduction:

In 1930 the band theory of solids was presented by F. Block, A. H. Wilson and others. This was the beginning of the science of semiconductor technology but for next 20 years no solid state device found any wide application in the field of Electronics Engineering. It was the invention of transistors by Bardeen, Brattain and Shockley (1948) that raised the stature and importance of Solid State Technology in the field of device fabrication. The American Multinational Electronic companies with their huge in-house Research and Development facilities made important break-through and remarkable innovations in Solid State Technology resulting in newer processes and techniques such as diffusion , ion-implantation, Deep Ultra-Violet Lithography, poly-Silicon emitter contact and low temperature epitaxial growth. Development of silicon and silicon based planar technology permitted the fabrication of transistors, diodes, capacitors, resistors, and their interconnections on a monolithic single crystal chip. Integrated Circuit (I. C.), technology helped microminiaturize complex electronic circuit, considerably cut down the power supply requirement, by dispensing away with wire interconnections reliability was considerably increased and by mass producing standardized chips the cost per chip was considerably reduced. Apart from these advantages, I. C. Technology gave very good temperature tracking of devices (active or passive) lying on same isothermal of the I.C. chip (temperature tracking results in favorable performance feature), gave matched transistors which are indispensable in I.C. design philosophy and gave higher speed by reducing the parasitic capacitances and by reducing the propagation delay. But I. C. technology limits the range of component values (resistors and capacitors) which can be monolithically realized and has no provision for close tolerance components and for inductors. The limited repertoire of component types and values put some constraint on the circuit designer. This constraint has been partly removed by the use of hybrid circuits and partly by a wider application of CMOS devices.. In hybrid circuits the I. C. chips are used in conjunction with thin film and thick film components which gives much greater flexibility to circuit designers especially in designing Analog Circuits (or linear/nonlinear circuits). In Analog circuits proliferation of I. C. technology has been much less because of lack of standardization in analog applications and because of very specialized requirements. Thin Film and Thick Film Technology afford much closer tolerances and much wider spectrum of component values.