Have you ever wondered about engineering life? How daunting would it be to identify the concepts of engineering? You are right. Here is the one topic which I chose to be termed as “Physical design.” Making a career in physical design is quite a challenging task, though it’s not impossible. You can make it easy by going through some of the questions asked by the interviewer, which I am going to share today in this article, but what the heck is the physical design that many of us are not aware of? Let’s deep dive into this.
The concept of physical design is predominantly used in integrated electric circuits. It is one of the most important steps, which is followed by circuit design. Specialized engineers can understand and familiar with this topic quite easily, and that’s why they know the bread and butter of it. In integrated electric circuits, this core step of physical design is split into two parts.
- Design and verification of the whole process
- Entire validation of the whole process
Now the whole system has been changed. As per modern standards, physical design is followed by certain process flows, which are the backbone. Thus, front-end design and backend design are the two backbone indicators in physical design. Moreover, these two backbone indicators have their own self-process: fabrication and manufacturing convert the entire design system into silicon diodes/dies. Then these small silicon dies are packed into separate integrated circuits.
A Career in Physical Design
Though in every discipline, you need a specific qualification to make a career in that particular field. The same goes for career opportunities for students and working professionals in the field of physical design. Therefore, I am going to share some of the important prerequisites which are necessary for those who are looking to make a career in physical design.
Qualification Needed
A candidate who is looking to make a career in physical design must have:
- Graduated from any recognized university with a bachelor’s degree in computer science or electrical engineering, master’s in electrical engineering, and Ph.D. in electrical engineering background and other related fields.
- For working professionals, one must have at least 5 years of experience in physical design. Other than that, candidates should be well versed with sound business knowledge and relevant industry practices in physical design like floor planning, site ground overview, hands-on experience with computer-aided design, and other design technicalities.
Skills
Apart from educational qualifications, you should have:
- Excellent communication skills
- Having well versed with certain languages like Python and other scripting languages like Java.
- Familiar with the concepts of physical verification, construction, and seamless validation of engineering projects
- Strong analytical skills
- Open to adapt and self-intellectual capability
- Self-motivated and able to work in a team
- Hands-on experience with certain workflows and workstations related to circuit design and maintenance and also the whole integrated circuits process flow.
- Knowledge of standardized physical design tools
- Experience in machine learning and how advanced technology circuit diodes work
Now, suppose all these skills and qualifications match your skills sets and the entire experience. What’s next, then? The next step is going to be the interview round.
You have been wondering which type of questions will be asked by an interviewer concerning a physical design interview? Moving to that part, I would like to mention some of the roles and responsibilities of a typical physical design engineer, which are a must before scheduling the interview process because there is no point in giving the interview if you are not aware of what to do as a physical design engineer.
Roles and Responsibilities of a Physical Design Engineer
The following are the roles and responsibilities of a physical design engineer:
- As a physical designer, you are responsible for managing the physical design team to ensure that the whole process is lean and systematic.
- You will also create a certain plan of action in terms of a blueprint that will not only improve the performance of integrated electric circuits but also utilize the efficiency and effectiveness of engineers and make consistent design flows.
- Activities meant for design flows include:
- Floor planning and selection
- Site ground overview
- Logic synthesizer diodes
- Time series analysis
- Analyze the voltage of the circuit
- Place and route analysis
- Thermal power analysis
- Making the manufacturing process simpler
- Liaising with the production engineering department to make sure the workflows and workstations are working effectively and efficiently
- You will also be responsible for implementing the latest advanced technologies concerning AI, data science, and machine learning to streamline the workflows.
- Responsible for generating the reports related to power and performance of the integrated circuits and disseminating the information to the management for contributing to the overall development of the organization.
- Managing the workflows of the entire system by implementing automation that caters to the entire infrastructure, which in turn leads to reliability, authenticity, and effectiveness of the design which you are going to finalize.
- You will also be handling all the design-related architecture with the auto-CAD machine to do testing with the design system and overall production processes.
- Identify the root cause of the problem and analyze the deficiencies and gaps of the particular design element.
These are some of the major roles and responsibilities of a particular physical design engineer. But again, this is such a challenging and lucrative job. For that, you need to face the interview. So now, to make it easier for you, I will list some of the questions which were frequently asked by the interviewer so that you can build the exact foundation by practicing some of them.
Top 12 Physical Design Interview Questions
Look, this is one of the crucial steps. If you face this and pass the race, then the game is yours. Here are some of the top 12 picked questions which are beneficial for you to pass the physical design interview. Let’s see!
Mention some of the common physical design inputs used by electrical engineers?
Some of the common physical design inputs used by electrical engineers are:
- Netlists
- Synopsis Designed Constraints
- Logical Workflow Library
- Physical Library
In electronics communication, what is input and output delay?
Input delay tells about how much delay is inherited by the signal coming from the input gate. And output delay tells about the combination of delay of gate input plus the delay which is caused due to load connected between the output of the gate.
Tell me about the components of physical verification?
Components of physical verification are:
- Electric Rule Check
- Layout Vs Schematic
- Logical Equivalence Check
- Design Rule Constraint Check
How do you make sure that you set up and fix the violations at the same appropriate time?
It can not be executed if we fix and set up violations simultaneously because then the delay happens. But there are only two alternatives to doing so:
- Kept the data paths as a buffer for sometime.
- Slowdown the frequency process of the clock.
There is a term commonly used in integrated circuits, i.e cross talk? Can you define it?
When an undesirable electrical connection happens between two nets, one net is parallel to another net, then the cross-talk effect exists.
Why is a floor plan required in physical design?
Sometimes, we can not meet the required area and performance. To make sure that the quality of the chip matches the entire area, you need to create a good floor plan. A proper floor plan effectively and efficiently utilizes the amount of area and thereby increases the performance of the signals of the different circuits.
Explain the concept of rows in the floor plan?
In the design, certain cells need to be standardized. Various standardized cells are placed in the rows to execute the tasks, and all rows have equal spacing and height. Only the difference comes concerning the width of the row. A row can build the ground as well as power connection between the VSS and VDD railing system.
- Highlight some of the advantages of the Non-default Rule for a good physical design of the site?
- Double width can be applied by using NDR.
- To avoid cross-talk interconnection between the IC’s
- To improve the accessibility of standardized cells as per the rules
- To minimize the congestion and timings of the metal data layer
- Improves the efficiency of the machines
There are certain inputs/libraries in the Floor Plan? What are those?
For maintaining the successful floor plan, we have certain inputs/libraries, which are:
- .sdc
- .lib
- .lef
- .tlu
- Height, the width of the overall floor plan
- Pin and pad position
Does cross-talk always create substantial violations in the circuit system?
Yes, it is created to add or subtract energy to the signals, leading to certain violations.
You are a physical design engineer? Suppose there is a low power design. How can you solve the problem?
I will take necessary actions in that case like:
- Apply gate to the clock.
- Apply power gating so that the entire voltage can be stabilized.
How can you improve the entire physical design if the workflow is not working?
One thing I will do by implementing DFM and DFT, which gives the quality and conformity of the entire design. Also,
- I will minimize the entire custom flow that will give better physical data capabilities.
- Using advanced tools like Synopsys IC2 to ensure the smooth flow of operations
Conclusion
It is working professionals, and the students need to practice types of questions before scheduling the physical design interview. If you practice regularly, you can win the race and get the maximum out because physical design is a lucrative and rewarding career for an individual. So, apply your learning and make or break them.
