An overview of integrated circuits

Integrated circuit, English for Integrated Circuit, abbreviated as IC; As the name implies, it is a circuit with specific functions that integrates a certain number of commonly used electronic components, such as resistors, capacitors, transistors, etc., and the wires between these components, through a semiconductor process. It is a new type of semiconductor device developed in the late 50s and 60s of the 20th century. It is through oxidation, lithography, diffusion, epitaxy, aluminum and other semiconductor manufacturing processes, the semiconductors, resistors, capacitors and other components required to form a circuit with certain functions and the connection wires between them are all integrated on a small silicon chip, and then soldered and packaged in a shell of electronic devices. Its encapsulated housings are available in round, flat or double in-line forms. Integrated circuit technology includes chip manufacturing technology and design technology, which is mainly reflected in the ability of processing equipment, processing technology, packaging and testing, mass production and design innovation.

Why are integrated circuits created? We know that there is a driving force behind any invention, and the driving force often comes from the problem. So what was the problem before the emergence of integrated circuits? Let's look at the world's first electronic computer born in the United States in 1946, it is a 150-square-meter, 30-ton behemoth, the circuit inside uses 17,468 tubes, 7,200 resistors, 10,000 capacitors, 500,000 wires, and consumes 150 kilowatts of electricity [1]. Obviously, the large area occupied and the inability to move are its most intuitive and prominent problems; How nice it would be if these electronic components and wires could be integrated on a small carrier! We believe that many people have thought about this issue and have come up with various ideas. Typical such as Dahmer, a scientist at the British Radar Institute, proposed at a conference in 1952 that the discrete components in the electronic circuit can be concentrated on a semiconductor wafer, and a small chip is a complete circuit, so that the volume of the electronic circuit can be greatly reduced and the reliability greatly improved. This was the idea of the early integrated circuit, and the invention of the transistor made this idea possible, and the first transistor was manufactured at Bell Labs in the United States in 1947, and before that, the current amplification function could only rely on large, power-hungry, fragile tubes. The transistor has the main function of the electron tube and overcomes the above shortcomings of the tube, so after the invention of the transistor, the idea of integrated circuits based on semiconductors soon appeared, and integrated circuits were quickly invented. Jack Kilby and Robert Noyce invented germanium integrated circuits and silicon integrated circuits respectively during 1958~1959.

At present, integrated circuits have played a very important role in all walks of life and are the cornerstone of the modern information society. The meaning of integrated circuits has far exceeded the definition range when it was first born, but its core part has not changed, that is, "integration", and the various disciplines derived from it are mostly carried out around the three questions of "what to integrate", "how to integrate", and "how to deal with the pros and cons of integration". Silicon integrated circuit is the mainstream, that is, the various components required to achieve a certain function of the circuit are placed on a silicon chip, and the whole formed is called an integrated circuit. For "integration", imagine that the house we have lived in may be easier to understand: many people lived in rural houses when they were children, when the main body of the house may be three or two bungalows, playing the function of a bedroom, a small yard at the door with a table and chairs, it acts as a living room, next to a small low house with cooking smoke, that is the kitchen, and the toilet with unique functions needs to have a certain isolation, it is possible to walk more than ten meters behind the house... Later, in the city, or rural urbanization, everyone lived in a building or suite, a suite, there is a living room, bedroom, kitchen, bathroom, balcony, maybe only tens of square meters, but with the original hundreds of square meters of rural houses of various functions, this is integration.

Of course, today's integrated circuits, its integration is far from a suite can be compared, perhaps a modern building can be better analogous: there are shops, offices, canteens, serviced apartments on the ground, several floors underground is a parking lot, and there is a foundation under the parking lot - this is the layout of integrated circuits, analog circuits and digital circuits are separated, sensitive circuits that process small signals are separated from control logic that flips frequently, and the power supply is placed in a separate corner. The layout of the rooms on each floor is different, and the corridors are different, with zigzags, I-shapes, and zigzag shapes - this is the design of integrated circuit devices, and transistors with folded shapes or "interphalange" structures can be used in low-noise circuits to reduce junction area and gate resistance. Each floor is directly reached by high-speed elevators, for efficiency and functional isolation, there may be multiple elevators, each elevator can reach different floors - this is the wiring of integrated circuits, power lines, ground wires are routed separately, and the line with large load is also wide; The clock is separate from the signal; Wiring between each layer vertically to avoid interference; The high-speed bus between the CPU and the storage is equivalent to the elevator, and the through-holes between the floors are equivalent to the elevator room...