Are you ready for a ‘technically challenging’ career? If yes, get ready for something beyond the preliminary levels of integrated circuits (ICs) involving small-scale integration (like logic gates) or medium-scale integration (like multiplexers and parity encoders). A much bigger world involving miniaturisation at levels where even a micrometre or a microsecond is considered a huge measure is waiting for you! This is the world of very large-scale integration (VLSI).
“Programmable logic devices, hardware description languages and design tools of today have changed the circuit design process to such an extent that it has become totally independent of the actual device manufacturing issues,” says Dr S. Karthik, engineering director, India Product Development Centre (IPDC), Analog Devices India. Let’s figure out the possibilities and the opportunities in the VLSI field for professionals with subject-matter expertise in electronics.
In the present scenario, the outsourcing aspect of VLSI design is attracting major international players in this field to India. In fact, most of the top global players in VLSI have their R&D setups in India playing very pivotal role in driving their overall strategy.
Moreover, the electronics industry in India is undergoing a gradual but rapid change from a software-driven outsourcing model to one that is increasingly focused on growth and development of the domestic market. According to India Semiconductor Association (ISA), the Indian semiconductor and embedded design industry is expected to earn revenues of $43 billion in 2015—a marked increase from the $5.9 billion in 2009. VLSI design services contribute approximately 13 per cent to overall revenues and 11 per cent to the overall workforce of the industry.
“Even in the recent downturn many companies did not cut the R&D spends. In fact, they are focused now, more than ever, on investing time and resources in creating the new applications for the wide varieties of market. Certain skill sets in this arena are always likely to be in short supply and therefore in great demand. So there is not only a need for talent in the semiconductor and electronics design industry but also a tremendous scope for growth for those who choose this path as a career,” says Surinder Bhagat, country manager-HR, Freescale Semiconductor India.
There is not only a need for talent in the semiconductor and electronics design industry but also a tremendous scope for growth for those who choose this path as a career.
—Surinder Bhagat, Country Manager-HR, Freescale Semiconductor India
Major recruiters in this field are Texas Instruments, PMC Sierra, Infineon, Alliance Semi- conductor, Freescale Semi- conductor, Analog Devices, Cadence, Synopsys, Mentor Graphics, HCL, Intel, Lucent, Micron Tech, National Semiconductor, Motorola, Philips Semiconductor, Qualcomm, Sasken, Atrenta, Conexant, Moschip, Cradle Tech, Syplicity, Wipro, TCS and eInfochips. There is also a very huge pool of SMEs with a headcount anywhere between 5 and 200 that is playing a pivotal role both in talent acquisition and development.
What role to choose?
Most of the jobs available in this field can be put under three broad categories: design, verification and implementation. Though most of the entry-level job profiles involve code entry, verification, synthesis and system-level engineering, the possibility of role diversification moving ahead is huge. The main job function involves engineering aspects of design, product, test, applications and process. Product engineering and test engineering functions are often combined efficiently into one role because of the interdependency and overlap of skills and tasks.
The roles are defined depending on the requirements of the job. “Typically, a design engineer takes specifications, defines architecture, designs circuits, runs simulations, supervises layout, tapes out the chip to the foundry and evaluates the prototype once the chip comes back from the factory,” says Anil Singh, director-training, CETPA Infotech. The design role itself offers further classification. For example, when the marketing team gives a company the product to design for the market, the architecture team is responsible for defining the chip design. You may work in such a team as a chip architect. You may also be involved in designing the functions or modules of the chip that are required to perform the well-defined tasks described by the architecture team. This role is defined as RTL designer. RTL design is written in a high-level logic description language such as Verilog or VHDL.
On the other hand, as a physical designer, your responsibilities will include placement and routing of digital blocks and chip-level integration. You have to take the netlist and perform a layout of the chip. This layout can be used to produce ‘masks,’ which are then used to manufacture the chip on a silicon wafer.
If you have interest in optimisation of circuit design or layout of custom cells like adders and shifters, you may start as a circuit designer.
According to Dr Karthik, with a sound knowledge of VLSI, you can be involved in the design phase of a project as a product engineer and ensure manufacturability; develop characterisation plan, assembly guidelines, quality assurance and reliability plan. Further, you can evaluate the chip in terms of characterisation, reliability qualification and manufacturing yield. “You will be responsible for production release as well as for customer returns, failure analysis and corrective actions including design changes during the post-production phase,” adds Dr Karthik.
In the role of a test or verification engineer, you have to generate and run tests on the chip to ensure proper functionality. It involves development of behavioural models, test benches and simulation environments, module integration, complete functional and regression test suites, functional coverage analysis and a reusable test infrastructure.
An application or implementation engineer defines new products from the customers’ point of view, based on the inputs received from the marketing team. “His mission is to ensure that the chip works in the designed system or used by the customers, and complies with appropriate standards (such as Ethernet, SONET and WiFi). He will be responsible for all customer technical support, firmware development, evaluation boards, datasheets and all product documentation such as application notes, trade shows, magazine articles, evaluation reports, software drives and so on,” says Dr Karthik.
How much rewarding can it be?
Generally, salaries are based on individual skillsets and qualifications. According to Bhagat, an engineer with a bachelor’s degree can expect anything between Rs 300,000 and Rs 600,000 per annum. Many companies give higher salaries to engineers with M.Tech/PhD degrees.
“Design engineers are the most sought after because of the industry’s emphasis on continuous new product development, miniaturisation and innovation in integration. Typically, a graduate with a master’s degree can expect about 10 per cent higher than the one with a bachelor’s degree, and someone with a PhD degree can expect a wide range,” says C.P. Ravikumar, technical director-university relation, Texas Instruments.
Design engineers are the most sought after because of the industry’s emphasis on continuous new product development, miniaturisation and innovation in integration.
—C.P. Ravikumar, Technical Director-University Relation, Texas Instruments
Based oncontinual performance, knowledge and competence, you can expect steep growth in remuneration as well as roles and responsib-ilities. The growth prospects for professionals in Indian companies are definitely promising given the scarcity of talent. For example, a young engineer can easily grow to become a team leader or project manager in a span of six to nine years. The ability to handle multitasking jobs may be a defining factor. As you gain experience, this field offers one of the best growth potentials, both on the technical as well as management front. Though the global recession has hugely affected starting salaries in the private sector at present, the previous year’s industry feedback reveals an average pay package between Rs 700,000 and Rs 1.5 million per annum for a four-to five-year-experienced professional.
How to get chosen?
“For VLSI design, companies prefer BE/B.Tech, ME/M.Tech and PhD holders with specialisation in electron¬ics, telecommunications and electri¬cal VLSI domains. Typically, these professionals should have hands-on experience in systems design, digital application-specific integrated circuit (ASIC) design, physical design, mixed-signal IC design, VHDL or VHSIC (very high-speed integrated circuit), VLSI design, circuit design and simulations, microcontrollers, digital PCB design and routing. You can expect an engineer with M.Tech/PhD degree and VLSI skills to have an edge in the job market,” explains Bhagat.
An aspirant in this field is expected to know the physics of semiconductor devices, linear systems, probability and random variables, engineering mathematics, circuit analysis and engineering electromagnetics.
—Dr S.Karthik, Engineering Director, India Product Development Centre, Analog Devices India
For working in this field, it is mandatory to have in-depth knowledge of either electronics, electrical or computer science. Though an engineering degree is the obvious qualification to earn, graduate and postgraduates in physics also qualify to become an engineer. The physics of semiconductor devices is the fundamental basis of VLSI.
“The subject of VLSI design is quite vast. It is not fair to expect both breadth and depth from a fresh recruit. At the undergraduate level, we expect a good understanding of fundamental concepts. Our campus recruitment is based on a written test and an interview.
The written test is separate for hardware and software engineers. The hardware paper has a section on aptitude, a section on digital design and a section on analogue design. We ask the students to select any one section between digital and analogue design. The software paper has an aptitude section and a software section. Candidates who fare well in the written test are shortlisted for interview. From my experience, the interviews are mostly based on problem-solving exercises and test the conceptual understanding rather than rote learning. We don’t pay too much importance to the B.Tech project done by the student,” says Ravikumar.
“For postgraduate students, our process is similar, except that we may go into their thesis. For candidates with a PhD, we also ask for a presentation where we invite our experts,” he adds.
One can understand this field from chip to ship level only by completing a successful project.
—Sasisekar K., President, RCS Online
The earlier, the better. If you ever tinkered with a broken radio set, you have already started. Academically, the right time to acquaint yourself with this niche field of electronics is when you are in the second or third year of engineering.
Dr Karthik points out, “An aspirant in this field is expected to know the physics of semiconductor devices, linear systems, probability and random variables, engineering mathematics (Fourier, Laplace and Z transforms), circuit analysis and engineering electromagnetics. For hiring a fresher, we look for in-depth understanding of second-and third-year engineering course curriculum rather than sector-
Solid Verilog/VHDL skills, familiarity with front-end design cycle, knowledge of synthesis and simulation tools, sound digital design fundamentals and knowledge of microprocessors would be an added advantage for any aspiring candidate.
What’s the right way to get started?
VLSI circuits are everywhere—your personal computer, your cellphone, your brand new state-of-the-art digital camera or for that matter any electronic gadget you dream to buy. Actually, this field involves packing more and more logic devices into progressively smaller areas. So the circuits that would have taken board-full of space can now be put into a small space few millimetres across!
According to Vivek Pawar, CEO, Sankalp Semiconductor, “The best way to start work on VLSI is to build core competency in this field. Component-level knowledge of electronic circuits and devices and thorough understanding of network theory, linear and digital design concepts are must-have.” Further, he emphasises on step-by-step knowledge acquisition of digital design, analogue design, board design and system design using different embedded tools.
To achieve this goal, Sankalp picks up second-and third-year electronics engineering students under its industry-academia ecosystem ‘Eklakshya’ and trains them following the ‘learning by doing’ principle.
According to Dr P.S. Bhat, director, Eklakhshya, “You may start with a typical analogue or digital design flow. For example, a digital design flow is specification→architecture→ RTL coding→RTL verification→synthesis→backend→tape out to foundry to get the end product.” Here the end product is a wafer with repeated number of identical ICs. All modern digital designs start with a designer writing a hardware description of the IC (using HDL) in Verilog/VHDL. A Verilog or VHDL program essentially describes the hardware (logic gates, flip-flops, counters, etc), the functionality and circuit block interconnects. Various electronic design automation (EDA) tools are available to synthesise a circuit based on the HDL. The most widely used synthesis tools come from Synposys and Cadence.
Without going into details, you may consider VHDL as ‘C’ language of the VLSI industry. VHDL stands for ‘VHSIC hardware definition language.’ This language is used to design the circuits at a high level, in two ways. It can either be a behavioural description of what the circuit is supposed to do or a structural description of what the circuit is made of. There are other languages too for describing circuits, such as Verilog, that work in a similar fashion. Both forms of description are then used to generate a very low-level description that actually spells out how all this is to be fabricated on the silicon chips.This results in the manufacturing of the intended IC.
Laying out the circuit components is a task common to all branches of electronics. The speciality in VLSI layout is the number of possible ways available to do this.
—Dr P.S. Bhat, Director, Eklakhshya
For an analogue design, the flow may vary to some extent: specifications → architecture→ circuit design→ simulation →layout→ parametric ex-traction/back annotation→final de-sign→tape out to foundry.
While digital design is highly automated now, very small portion of analogue design can be automated. For analogue, there is a hardware description language called AHDL, but it is not widely used as it does not accurately give the behavioural model of the circuit because of the complex analogue behaviour of the circuit. Many analogue chips are termed as ‘flat’ or non-hierarchical designs. This is true for small-transistor-count chips such as operational amplifiers, filters or power management chips. For more complex analogue chips such as data converters, the design is done at the transistor level, building up to the cell level, then the block level and finally integrated at the chip level. Not many EDA tools are available for analogue design even today and thus analogue design remains a difficult art. SPICE is the most useful simulation tool for analogue as well as digital design.
Keep in mind that digital VLSI circuits are predominantly CMOS-based. So the way normal blocks like latches and gates are implemented is different from what you have seen so far. However, the behaviour remains the same. All the miniaturisation involves new things to consider. A lot of thought has to go into the actual implementation as well as design.
Further, Dr Bhat points out, “Lay-ing out the circuit components is a task common to all branches of electronics. The speciality in VLSI layout is the number of possible ways available to do this; there can be multiple layers of different materials on the same silicon, different arrangements of smaller parts for the same component and so on. Each one has a separate layout.”
Layout is responsible for the functionality of the circuit. Power dissipation and speed in a circuit present a trade-off; if we try to optimise one, the other is affected. The choice between the two is determined by the way you choose to layout the circuit components. Layout can also affect the fabrication of VLSI chips, making it either easy or difficult to implement the components on the silicon.
How to tackle the reality?
Know where to apply your skillset. Analogue designs are mostly used for small-transistor-count precision circuits such as amplifiers, data converters, filters, phase-locked loops and sensors. In digital design, the progress in the fabrication of ICs has enabled designers to create fast and powerful circuits in smaller and smaller devices. This also means that you can pack a lot of functionality into the same area. The biggest application of this ability is in the design of ASICs. These ICs are created for specific purposes. The most common application area for an ASIC is DSP—signal filtering, image compression, etc. To understand better, consider the fact that a digital wristwatch normally consists of a single IC doing all the time-keeping as well as extra features like games, calendar, etc. SoCs (systems on a chip), on the other hand, are highly complex mixed-signal circuits (digital and analogue on the same chip). Network processor chips and wireless radio chips are examples of an SoC.
If it looks complicated to you, here’s an advice: “One can understand this field from chip to ship level only by completing a successful project,” says Sasisekar K., president, RCS Online. He advises to select designs that can address both the cost sensitivity and needs of the Indian market; for example, small chips for e-books or biosensors like blood-sugar monitoring devices. You should even try to get involved in stages like foundry-level fabrication and IP creation. In fact, these kinds of involvements can build a future generation of entrepreneurs in this field.
So don’t panic over the current job scenario; the time is perfect to resurrect your thought process on a very large scale. Devote your time to become an expert in VLSI. It will definitely bring ‘very large’ opportunities in the future.
The author is a consultant-editorial, industry & academia interface at EFY