Source: What is the technology behind manufacturing a semiconductor chip? (The Hindu, April 8, 2024)
Semiconductor chip manufacturing is limited to a few regions globally. Disruptions in the supply chain during the pandemic highlighted the importance of chip manufacturing infrastructure. Recent geopolitical tensions have further emphasized the need for local manufacturing capabilities.
Investment Initiatives in India
- India, recognizing the significance, is investing in chip manufacturing infrastructure.
- The TATA group has partnered with Taiwan’s Powerchip Semiconductor Manufacturing Corporation (PSMC).
- A 300mm wafer fabrication plant is being set up in Gujarat.
Government Approvals
- The Government of India has approved two assembly and test plants in Gujarat and Assam.
- These initiatives aim to enhance domestic semiconductor production capacity.
Semiconductor Chips
Definition
- A semiconductor chip has properties between a conductor and an insulator.
- In its purest form, it’s a weak conductor of electricity.
Manufacturing Process
- Small amounts of substances called ‘dopants’ alter semiconductor’s electrical properties.
- Complex circuits are created by injecting specific dopants into pure semiconductors.
- The process resembles creating art using stencils and paint.
- Masks in the industry act as stencils, and dopants serve as paint.
Transistors
Definition
- A transistor is an early electronic component made from a semiconductor.
- It’s highly versatile, often functioning as an electronic switch.
Functionality
- Transistors on a semiconductor chip can number in the millions/billions.
- They work collectively to execute logical and computational tasks.
Applications
- Besides acting as switches, transistors can amplify weak signals, like those in cell phones.
- They’re crucial components in circuits for generating and processing high-frequency signals.
Integration
- Today, various transistor functions are consolidated into a single semiconductor chip.
- For instance, the WiFi chip in mobile phones contains these diverse transistor functionalities.
Technological Leap
- The transistor showcased the potential of a single semiconductor device.
- Advancements led to printing multiple devices on a single semiconductor, forming entire circuits.
Impact
- These breakthroughs paved the way for the semiconductor revolution.
- Recognized by Nobel Prizes in 1956 and 2000, they marked significant milestones in technology.
Fabrication Technology
Technological Progression
- Technology has advanced rapidly since the inception of the semiconductor chip over six decades ago.
- New manufacturing technologies have been consistently introduced, leading to significant miniaturization.
Miniaturization and Switching Capability
- Miniaturization of semiconductors has increased drastically, allowing for smaller and more intricate patterns.
- Transistors have shown remarkable improvements in switching capability, enabling faster computations and reduced power consumption.
Technology Labels
- Manufacturing technologies are often labeled as ’45nm’, ’28nm’, or ’16nm’.
- ‘nm’ stands for nanometer, representing an extremely small unit of length.
Significance of Numbers
- These numbers indicate the level of miniaturization achievable with each technology.
- Smaller numbers represent finer dimensions, often referring to the size of a single transistor.
Three-Dimensional Approach
- Researchers are exploring the third dimension (height) in semiconductor design.
- Increasing the height of transistors can ensure reliable performance as their length and breadth decrease.
Circuit Stacking
- Stacking entire circuits on top of each other is another method to reduce semiconductor chip sizes.
- This approach offers potential for further miniaturization and optimization of chip design.
Wafers
Manufacturing Process
- Like postage stamps on a sheet, semiconductor chips are printed on circular pieces of semiconductor known as wafers.
- These wafers are diced to create individual chips, typically in arrays of 300-400.
Wafer Size
- Larger wafer sizes allow for more chips per wafer, enhancing production efficiency and cost-effectiveness.
- The current industry standard is 300mm, with efforts to move towards 450mm wafers ongoing.
Benefits of Larger Wafers
- While transitioning to larger wafer sizes presents technical challenges and capital expenses, it proves economical in the long term.
Chip Packaging and Testing
Packaging Process
- After dicing, individual chips are packaged in protective coverings.
- Tiny wires are routed from the device to the package boundary, supplying power and transmitting signals and data.
Testing
- Each chip undergoes functionality verification and stress testing to ensure reliability.
- This process occurs in assembly and test plants.
India’s Semiconductor Ecosystem
Chip Design Industry
- India boasts a thriving chip design industry since the 1990s.
- Chip design, largely facilitated by computer-aided design, allows engineers to design chips entirely in software.
Design and Manufacturing
- The chip design process involves specifying functionality, translating it into electronic circuits, and optimizing for various factors like speed, power consumption, and size.
- Designs are sent to fabrication plants for manufacturing, resembling the process of designing a graphic novel on a computer and sending it to a publisher for printing.
Interdisciplinary Opportunities
- India’s semiconductor manufacturing efforts can leverage its existing chip design ecosystem.
- Semiconductor manufacturing involves various disciplines, offering opportunities for professionals like process engineers, data scientists, material scientists, physicists, and chemical engineers to contribute meaningfully.