Technology behind Semiconductor chip manufacturing

Source– This post on Technology behind Semiconductor chip manufacturing is based on the article “What is the technology behind manufacturing a semiconductor chip?” published in “The Hindu” on 7th April 2024.

Why in the News?

Recently, a rise in semiconductor global capability centres (GCCs) has been seen in India with a focus on design, testing and validation. The TATA group has partnered with Taiwan’s Powerchip Semiconductor Manufacturing Corporation (PSMC) to set-up a 300mm wafer fabrication plant in Gujarat. It will roll out its first 28nm chip in 2026. Two assembly and test plants in Gujarat and Assam have also been recently approved by the Government of India.

About semiconductor chip

1. Semiconductors have electrical properties between conductors and insulators.

2. Its electrical properties can be changed by adding small amounts of certain substances called ‘dopants’.

3. By taking a pure semiconductor and carefully injecting certain parts with specific dopants, complex circuits can be ‘printed’ on the semiconductor.

What is transistor and how it is used?

1. The transistor is one of the earliest electronic components to be built using a semiconductor. It is an extremely versatile device. For ex- It can function as an electronic switch.

2. A typical semiconductor chip can have millions/billions of these interconnected switches that work together to perform various logical and computational operations.

3. Millions of these tiny switches can be found on a single chip, which work together to perform complex tasks.

4. Transistors are essential for devices that need to process signals, like those used for WiFi.

Advances made in the fabrication technology

Technology has progressed at a relentless pace since the semiconductor chip was first conceptualised,  more than six decades ago.

Impressive gains in the switching capability of the transistors- The transistors are able to switch on-and-off faster (more computations per second) and with lesser power consumption (longer battery life and lesser heat dissipation).

New manufacturing technology- The industry has used labels like ‘45nm’, ‘28nm’ and ‘16nm’ to introduce each new manufacturing technology. These numbers convey the level of miniaturisation that is achievable using a particular technology (so smaller is better).

Researchers aiming for decreased sizes-  Researchers are aiming to stacking entire circuits on top of one another is another way to continue to shrink semiconductor chip sizes.

Wafer

Wafer is a circular piece of semiconductor on which an array (typically 300-400) of chips are printed. This is then diced to create individual chips. A larger wafer size allows more chips to be printed on a single wafer which makes chip production faster and cheaper.

Wafer sizes used in the industry have constantly been increasing. The current size if the wafer is 300mm which is approximately 12 inches. Efforts are ongoing to move to a 450mm wafer size.

While moving to a larger wafer size has its technical challenges and capital expenses, it has proven to be economical in the long run.

Assembly and test plant

A chip is tested for its functionality and stress (subjecting the chip to high temperature and voltages) to ensure reliability during its lifetime. This is done in assembly and test plant.

About India’s semiconductor ecosystem

1. India’s chip design sector has been booming since the 1990s, leveraging computer-aided design to create semiconductor chips entirely in software.

2. This involves outlining the chip’s functions, converting these into electronic circuits, and refining them for efficiency, power, and size by skilled engineers using desktops.

3. The finalized design is then sent as a file to a manufacturing plant for production, akin to sending a digital graphic novel to a publisher.

4. Semiconductor production opens doors for a broader range of experts, including process and control engineers, data scientists, material scientists, physicists, and chemical engineers, to significantly contribute to the industry.

Read more: Semiconductor fabrication

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