General Studies Paper 3

INTRODUCTION

• Sand plays a vital role in our daily lives. Used in its raw form, it is the foundation material for building homes. Purify the sand a little more and it becomes the foundation of the semiconductor industry. India is currently waking up to its opportunities vis-à-vis semiconductors: access to the underlying technologies has been a long-standing dream of our nation. Success on this front would place India among a small, elite group of nations that have access to the tech as well as provide thousands of highly skilled jobs.

A SEMICONDUCTOR CHIP

• At its core, a semiconductor chip is composed of transistors, which in turn are meticulously crafted from a specially selected material, typically silicon.
• One major function of a transistor is to encode information in the form of 0s and 1s, and to manipulate them to produce new information.
• These transistors have three parts: the source, the gate, and the drain (or the sink).
• The flow of current between the source and the drain points is regulated by the voltage applied to the gate.
• This arrangement gave rise to the specific meaning of ‘gate’ in computing – analogous to a physical gate, but operating with electrical means rather than mechanical ones.
• By manipulating the gate to ‘open’ or ‘close’, the transistor stores and manipulates the data in a semiconductor chip.
• The semiconductor stores information in the form of bits.
• Each bit is a logical state that can have one of two values at a time.
• The more bits a semiconductor can store and the more quickly it can manipulate them, the more data transistors can process.
• The three parts of a transistor are connected to multiple metal layers on top of them that apply voltages, forming a complex mesh of electrical connections with the transistors.
• The metal layers allow selective access to a transistor and provide the versatility required for the chip to execute multiple tasks.

NODE NUMBER

• Through history, the names of semiconductor nodes have been based on two numbers: the length of the gate and the distance between adjacent metal strips connected to the gate; the latter, when measured centre to centre, is called the pitch.
• These dimensions were often equal. The size of transistors has progressively shrunk over the years.
• The smaller a transistor becomes, the more of them can be fit on a semiconductor chip, the more data the chip can store, the more computing power there will be.
• Yet as transistors continued to become smaller, researchers spotted a discrepancy between the gate length and the metal pitch, rooted in the fact that while smaller transistors generally resulted in faster operation, reducing the size of metal wires created different problems, including not being able to transport data fast enough.
• From a technical standpoint, node names hold no significance vis-à-vis the actual physical dimensions. Instead, marketers use them to mean one node is better than a previous iteration.

NEED OF LEGACY NODES TO INDIA

• The choice of nodes, just like our choices in life, involve compromises.
• While advanced nodes range from 10 nm to 5 nm, India’s current focus is around 28 nm or higher.
• However, this doesn’t mean we are attempting to develop outdated chips.
• Starting with legacy nodes can offer numerous advantages, including equipping us for long-term success.
• While the most advanced nodes are used in devices like smartphones and laptops, many applications require legacy nodes, including robotics, defence, aerospace, industry automation tools, automobiles, Internet of Things, and image sensors – because they are more cost-effective.
• The principal revenue source for any fabrication facility, or ‘fab’, is its most advanced node.
• But almost every commercial fab also maintains the production of legacy nodes to fulfil demands in the aforementioned areas.

WAY FORWARD

• Indeed, as the demand for electric cars – together with the ever-increasing demand for complementary electronics in the car, like music players – increases, the demand for legacy nodes will also increase.
• Given these facts, the Indian government and private players are sensible to begin their semiconductor journey with the legacy nodes, improving their game over time.
• Who knows – maybe one day India will be the semiconductors hub of the world.