IC Basic Planar Process MCQ [Free PDF] - Objective Question Answer for IC Basic Planar Process MCQ Quiz

16. Find the coating material used for the photo etching process along with its thickness range.

A. Kodak photoresist (5000-10000Å)
B. Kodak photoresist (1000-5000Å)
C. Kodak photo etchant (1000-5000 Å)
D. Kodak photo etchant (500-1000 Å)

Answer: A

The coating material is Kodak photoresist. It is a photosensitive emulsion film coated on the wafer to remove SiO₂ from the desired region.

17. Which type of etching process is preferred to make the photoresist immune to etchants?

A. None of the mentioned
B. Wet etching
C. Plasma etching
D. Chemical etching

Answer: C

Plasma etching is also called dry etching. The major advantage of the dry etching process is that it is possible to achieve smaller line openings (<1µm) compared to other processes.

18. Which of the following statement is not true?

A. X-ray and Electron beam lithography technique, produce device dimensions down to the submicron range.

B. Ultraviolet lithography has limitations due to diffraction effects of wavelength.

C. The cost of X-ray or Electron beam is less compared to Ultraviolet photolithography.

D. The exposure time is less in Ultraviolet compared to X-ray or Electron beam lithography.

Answer: C

The cost of an X-ray or Electron beam is very high and thus, it is an expensive process. Therefore, it is used only when very small device dimensions (<1 µm) are needed.

19. For photographic purposes usually coordinate graph is preferred for artwork because,

A. It is a precision drafting machine
B. Cutting head can be positioned accurately
C. It can be moved along two perpendicular axes
D. All of the mentioned

Answer: D

A coordinate graph is a drafting machine that outlines the pattern cutting through the red Mylar without damaging the clear layer underneath.

20. Which of the following is added as an impurity to p-type material in the diffusion process?

A. Phosphorous pentaoxide (P₂O₅)
B. Phosphorous oxychloride (POcl₃)
C. Boron oxide (B₂O₃)
D. None of the mentioned

Answer: C

Boron is a p-type material, whereas Phosphorous is an n-type material.

21. In the fabrication of monolithic ICs, Boron chloride is added as an impurity in the diffusion process. Find the diffusion time, if the furnace is heated up to 1200^oc.

A. 1 hour
B. 2 hours
C. 45 minutes
D. 30 minutes

Answer: B

In the diffusion process, the depth of diffusion of impurities depends upon the time taken for diffusion, which normally extends for more than 2 hours.

21. Which component is not used as an impurity in the diffusion process?

A. Phosphorous
B. Boron chloride
C. Phosphorous pentaoxide
D. Boron oxide

Answer: A

The elemental form of Phosphorous is not added directly as an impurity in the diffusion process.

22. In the ion implantation method, penetrating the ions into the silicon wafer depends upon

A. Accelerating voltage
B. Accelerating speed
C. Accelerating current
D. All of the mentioned

Answer: A

The depth of penetration of any particular type of ion increases with increasing accelerating voltage.

23. What is the advantage of using the Ion implantation process?

A. Lateral spreading is more
B. Performed at high temperature
C. Beam current-controlled from outside
D. Performed at low temperature

Answer: C

In the diffusion process, the temperature has to be controlled over a large area inside the oven, whereas in the ion implantation technique, accelerating potential and the beam current are electrically controlled from the outside.

24. The major disadvantage of the PN-junction isolation technique is:
A. Formation of Parasitic Resistance
B. Formation of Parasitic Capacitance
C. Formation of Isolation island
D. None of the mentioned

Answer: B

The presence of Parasitic Capacitance at the isolating PN-junction results in an inevitable capacitor coupling between the component and substrate. This also limits the performance of circuits at high frequencies.

26. Which isolation technique is used in applications like military and aeroscope?

A. Thin-film isolation
B. PN-junction isolation
C. Barrier isolation
D. Dielectric isolation

Answer: D

In dielectric isolation, a layer of solid dielectric is used for isolation purposes. This layer is thick enough such that its associated capacitance is negligible. Moreover, it is more expensive, which is justified by its superior performance.

27. Aluminium is usually used for the metallization of most IC as it offers

A. Relatively a good conductor
B. High resistance
C. Good mechanical bond with silicon
D. Deposition of aluminum film using vacuum deposition

Answer: C

Aluminum forms low resistance (it is a good conductor of electricity). Therefore, it forms ohmic contact (Semiconductor-metal contact) with p-type silicon and heavily doped n-type silicon.

28. How the aluminum film coating is carried out in the metallization process?

A. Heating and pouring aluminum in the required place.
B. Aluminium is vacuum evaporated and then condensed
C. Placing the aluminum in the required place and then heating it using tungsten
D. None of the mentioned

Answer: B

The metallization process takes place in the Vacuum evaporation chamber, where the material is evaporated by focussing a high power density electron beam. Vapors then hit the substrate and get condensed to form a thin-film coating.

29. What type of packing is suitable for Integrated Circuits?

A. Metal can package
B. Dual-in-line package
C. Ceramic flat package
D. All of the mentioned

Answer: D

These packages are the three different possible packages available in Integrated Circuits. Its usage depends upon the number of leads required for application.

30. Metal can IC packages are available in

A. 42 leads
B. 16 leads
C. 12 leads
D. 24 leads

Answer: C

The maximum lead available in a metal can IC package is 12. The remaining lead numbers are commonly available in dual-in-line packages.

31. What process is used in the semiconductor industry to fabricate Integrated Circuits?

A. Silicon wafer preparation
B. Silicon planar process
C. Epitaxial growth of silicon
D. Photolithography process

Answer: B

The planar process (Silicon planar technology) in the semiconductor industry built individual components. It is the primary process by which Integrated Circuits are built. The other processes are the different steps involved within the planar process.

32. Which semiconductor is most widely used for the fabrication of Integrated circuits?

A. Germanium, Ge
B. Gallium Arsenide, GaAs
C. Silicon, Si
D. All of the mentioned

Answer: C

Silicon is abundantly available in the form of sand. It is possible to form superior stable SiO₂(Which has superb insulating properties). Whereas GaAs is more difficult to grow in crystal form and Ge crystal will be destroyed at high temperature.

33. What will be the next step after slicing (process) silicon wafers?

A. All of the mentioned
B. Lapping
C. Polishing
D. Chemical

Answer: A

When the silicon ingots are sliced for the given industrial dimension. It gives a rough surface and thus undergoes lapping, polishing, and chemical processing steps to get a smooth surface.

34. During the ion implantation process (before the ion strike the wafer) the accelerated ions are passed through

A. Strong Electric field
B. Strong Magnetic field
C. Strong Electric and Magnetic Field
D. None of the mentioned

Answer: B

During arc discharge in ion implantation, unwanted impurities get generated. The magnetic field acts to separate unwanted impurities from dopant ions.

35. In which method shallow penetration of dopants is possible?

A. Ion implantation
B. Vertical diffusion
C. Horizontal diffusion
D. Dopants diffusion

Answer: A

The depth of diffusion in this method can be easily regulated by control of the incident ion velocity and is capable of shallow penetration.

36. Which method is most suitable for silicon crystal growth in silicon wafer preparation?

A. Float zone process
B. Bridgeman-Stockbarger method
C. Czochralski crystal growth process
D. Laser heated pedestal growth

Answer: C

Czochralski crystal growth processes obtain a single crystal of semiconductor. The most important application of this method may be the growth of a large cylindrical ingot of single-crystal silicon.

Pages: 1 2

Related Posts