Layout Design Rules — MCQs – EE

1. Layout design rules are primarily used to:
(A) Ensure manufacturability and reliability of ICs
(B) Improve simulation speed
(C) Reduce software complexity
(D) Enhance logical performance only

2. The layout design rules are provided by:
(A) The semiconductor foundry or fabrication facility
(B) The circuit designer
(C) The CAD tool developer
(D) The packaging engineer

3. The purpose of design rules is to:
(A) Avoid physical and electrical failures during fabrication
(B) Increase transistor count
(C) Improve logic synthesis
(D) Eliminate simulation errors

4. The two main types of layout design rules are:
(A) Lambda-based and Absolute rules
(B) Logical and Physical rules
(C) Linear and Non-linear rules
(D) Static and Dynamic rules

5. The term “lambda” in layout design rules refers to:
(A) A scalable unit representing half of the minimum feature size
(B) The wavelength of light used in photolithography
(C) The length of the transistor channel
(D) The oxide thickness

6. Lambda-based rules are useful because they:
(A) Allow technology-independent layout scaling
(B) Are specific to one fabrication process
(C) Eliminate DRC checks
(D) Reduce logic delay

7. Absolute design rules are given in:
(A) Micrometers or nanometers
(B) Logic levels
(C) Frequency units
(D) Electrical voltage

8. The minimum spacing between two metal lines ensures:
(A) No short circuit or leakage between lines
(B) Higher current flow
(C) Faster signal propagation
(D) Reduced resistance

9. The minimum width rule defines:
(A) The narrowest allowable line of a layer
(B) The maximum size of the transistor
(C) The gate oxide thickness
(D) The power supply width

10. The minimum overlap rule ensures:
(A) Proper alignment between layers
(B) Isolation between layers
(C) Reduction in chip area
(D) Increased current density

11. The minimum enclosure rule specifies:
(A) How much one layer must surround another
(B) The total area of the chip
(C) The oxide thickness
(D) The transistor channel length

12. The purpose of contact and via rules is to:
(A) Ensure reliable connections between layers
(B) Reduce metal resistivity
(C) Increase chip size
(D) Minimize leakage current

13. The metal layer rules are critical for:
(A) Interconnection reliability
(B) Logic simulation
(C) Noise immunity
(D) Device threshold control

14. The active area in layout design represents:
(A) The region where transistors are formed
(B) The metal interconnect area
(C) The passivation layer
(D) The substrate contact

15. The polysilicon layer is primarily used to form:
(A) The gate of MOS transistors
(B) The source and drain regions
(C) The metal interconnects
(D) The substrate

16. The well contact rules are important to:
(A) Prevent latch-up in CMOS circuits
(B) Reduce capacitance
(C) Increase channel mobility
(D) Improve propagation delay

17. A Design Rule Check (DRC) tool is used to:
(A) Verify that the layout meets all fabrication constraints
(B) Simulate circuit timing
(C) Perform logic synthesis
(D) Analyze transistor switching

18. A layout that violates design rules may lead to:
(A) Fabrication defects or circuit failure
(B) Faster circuit operation
(C) Lower cost manufacturing
(D) Improved yield

19. The spacing rule between two wells prevents:
(A) Electrical shorts and latch-up
(B) Power loss
(C) Signal delay
(D) Metal migration

20. The minimum contact size is defined to ensure:
(A) Reliable electrical connection and manufacturability
(B) Reduced capacitance
(C) Faster switching
(D) Lower leakage current

21. The oxide isolation in layout is used to:
(A) Electrically isolate neighboring transistors
(B) Reduce metal resistance
(C) Connect different layers
(D) Increase transistor speed

22. The metal density rule ensures:
(A) Uniform planarization during fabrication
(B) Maximum chip performance
(C) Minimum leakage
(D) Better logical performance

23. The antenna effect during fabrication is caused by:
(A) Long metal lines accumulating charge
(B) Misalignment of layers
(C) High resistance interconnects
(D) Thick oxide layers

24. Dummy fills in layout are used to:
(A) Maintain uniform metal density
(B) Reduce transistor leakage
(C) Increase speed
(D) Adjust threshold voltage

25. The minimum via enclosure rule prevents:
(A) Via misalignment and open circuits
(B) Leakage current
(C) Thermal issues
(D) Gate oxide breakdown

26. Layout compaction is performed to:
(A) Minimize chip area while following design rules
(B) Increase oxide thickness
(C) Reduce gate delay
(D) Eliminate DRC checks

27. In submicron technologies, design rules become:
(A) More restrictive and complex
(B) Easier and less detailed
(C) Independent of scaling
(D) Larger and relaxed

28. The purpose of latch-up prevention rules is to:
(A) Avoid unwanted current paths in CMOS circuits
(B) Increase logic levels
(C) Reduce propagation delay
(D) Improve noise margin

29. The concept of “scalable design rules” allows:
(A) Layout portability across different technologies
(B) Faster clock speeds
(C) Reduced leakage current
(D) Simplified testing

30. Violating layout design rules may result in:
(A) Reduced yield and chip failure
(B) Improved yield
(C) Faster processing
(D) Increased noise immunity