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ICs, or microcircuits, are miniaturized electronic circuits composed of semiconductors and passive components. They are commonly referred to as chips and are produced on semiconductor wafers.

Integrated circuits (ICs), also known as microcircuits, microchips, or simply chips, are a miniaturized form of electronic circuits. They consist of various electronic components, primarily semiconductor devices, as well as passive components, and are often manufactured on the surface of a semiconductor wafer.

The development of integrated circuits revolutionized the field of electronics by allowing for the integration of multiple electronic components onto a single chip. This miniaturization not only reduced the physical size of circuits but also improved their performance, reliability, and cost-effectiveness.

Integrated circuits are widely used in various electronic devices and systems, including computers, smartphones, televisions, automobiles, and many other consumer and industrial applications. They play a crucial role in modern technology, enabling the advancement of digital systems, telecommunications, and countless other areas of electronics.

The manufacture of circuits on the surface of semiconductor chips is known as thin-film integrated circuits. Another type, thick-film integrated circuits (hybrid integrated circuit), integrates independent semiconductor devices and passive components onto a substrate or a printed circuit board, forming a miniaturized circuit.

From 1949 to 1957, prototypes were developed by Werner Jacobi, Jeffrey Dummer, Sidney Darlington, and Yasuo Tarui, but modern integrated circuits were invented by Jack Kilby in 1958. For this invention, he was awarded the Nobel Prize in Physics in 2000. However, the practical development of integrated circuits was achieved earlier by Robert Noyce, who passed away before 1990.

After the invention and mass production of transistors, various solid-state semiconductor components such as diodes and transistors replaced the function and role of vacuum tubes in circuits. With advancements in semiconductor manufacturing technology in the mid-20th century, integrated circuits became feasible. Compared to manually assembling circuits using individual discrete electronic components, integrated circuits can integrate a large number of micro-transistors into a small chip, representing a significant advancement. The mass production capability of integrated circuits, their reliability, and the modular approach to circuit design ensured rapid adoption of standardized integrated circuits to replace designs using discrete transistors. Integrated circuits have two main advantages over discrete transistors: cost and performance. The low cost is due to the chip printing all components as a unit using photolithography, rather than manufacturing one transistor at a time. High performance is due to the rapid switching of components, which consumes lower energy because the components are small and close to each other. By 2006, chip sizes ranged from a few square millimeters to 350 mm², with up to a million transistors per mm².

Development of Integrated Circuits

The most advanced integrated circuits are the cores of microprocessors or multi-core processors, which can control everything from computers to mobile phones to digital microwaves. Although the cost of designing and developing a complex integrated circuit is very high, when distributed across typically millions of products, the cost of each integrated circuit is minimized. Integrated circuits have high performance because the small size leads to short paths, allowing low-power logic circuits to operate at fast switching speeds. In recent years, integrated circuits have continued to shrink in size, allowing more circuits to be packaged on each chip. This increases the capacity per unit area, reduces costs, and increases functionality, following Moore’s Law, which states that the number of transistors in an integrated circuit doubles every 1.5 years. In summary, as the size decreases, almost all indicators improve, with unit cost and switching power consumption decreasing, and speed increasing. However, integrated circuits with nanoscale devices also face problems, primarily leakage current. As a result, there is a significant increase in speed and power consumption for end users, and manufacturers face sharp challenges in using better geometry. This process and the expected progress in the coming years are well described in the International Technology Roadmap for Semiconductors.

Over the past half century since its development, integrated circuits have become ubiquitous, making computers, mobile phones, and other digital appliances an indispensable part of the social structure. This is because modern computing, communication, manufacturing, and transportation systems, including the internet, all depend on the existence of integrated circuits. Many scholars even consider the digital revolution brought about by integrated circuits to be the most important event in human history. The maturity of ICs will lead to a great leap forward in technology, both in design and semiconductor process breakthroughs, which are closely related.

Classification

There are many ways to classify integrated circuits. Based on whether the circuit is analog or digital, they can be divided into: analog integrated circuits, digital integrated circuits, and mixed-signal integrated circuits (analog and digital on one chip). Digital integrated circuits can contain anything from a few thousand to millions of logic gates, flip-flops, multiplexers, and other circuits in a few square millimeters. These circuits’ small size allows for higher speed, lower power consumption (see low-power design), and reduced manufacturing costs. These digital ICs, represented by microprocessors, digital signal processors, and microcontrollers, operate using binary signals of 1s and 0s.

Manufacturing

Since the 1930s, semiconductors from the periodic table of elements have been studied, and certain semiconductors have been considered the most likely materials for solid-state vacuum tubes by researchers such as William Shockley at Bell Labs. From copper oxide to germanium, and then to silicon, materials were systematically studied from the 1940s to the 1950s. Although some III-V compound semiconductors from the periodic table, such as gallium arsenide, are used for special purposes such as light-emitting diodes, lasers, solar cells, and high-speed integrated circuits, single-crystal silicon has become the mainstream substrate for integrated circuits. It took several decades to develop methods for creating defect-free crystals.

Single-crystal silicon wafers (or III-V family, such as gallium arsenide) are used as the substrate, and then MOSFETs or BJTs are made using techniques such as lithography, doping, and CMP. Then, wire connections are made using thin film and CMP techniques to create wires. This completes the chip manufacturing process. Based on product performance requirements and cost considerations, the wires can be divided into aluminum processes (mainly sputtering) and copper processes (mainly electroplating, see Damascene). The main process technologies can be divided into several categories: photolithography, etching, diffusion, thin film, planarization, and metallization.

ICs consist of many overlapping layers, each defined by video technology and usually represented with different colors. Some layers indicate where different doping diffuses into the substrate (forming a diffusion layer), some define where additional ions are implanted (implantation layer), some define conductors (polysilicon or metal layers), and some define connections between conductor layers (vias or contact layers). All components are made up of specific combinations of these layers. In a complementary metal-oxide-semiconductor (CMOS) process, all gate layers (polysilicon or metal) form transistors through the diffusion layer. Electronic Components Distributor , the length-width ratio of the resistor structure, and the combined surface resistance coefficient determine the resistance. Due to size limitations, only small capacitors can be produced on ICs. Less common inductance structures can be manufactured as chip-mounted inductors or spiral models. Because CMOS devices only conduct current between logic gates, CMOS devices consume much less current than bipolar devices (such as bipolar transistors). By drawing multiple transistors on a silicon wafer, logic circuits with different functions can be drawn.

Random access memory is the most common type of integrated circuit, so the highest-density devices are memories. Even microprocessors have memory. Although the structure is very complex—in recent decades, chip widths have continued to decrease—the layers of integrated circuits are still much thinner than their width. The manufacturing process of the component layer is very similar to the photographic process. Although light waves in the visible spectrum cannot be used to expose the component layer because they are too large, high-frequency photons (usually ultraviolet light) are used to create patterns for each layer. Because each feature is very small, an electron microscope is a necessary tool for a process engineer debugging the manufacturing process.

Before packaging, each device undergoes testing. The testing process is known as wafer testing or wafer probing. The wafer is cut into rectangular pieces, each called a die. Each good die is attached to pads with aluminum or gold wires and connected to the package. After packaging, the same or similar ATE used in wafer probing is used for final inspection. Testing costs can reach 25% of the manufacturing cost of low-cost products, but for low-output, large, and/or high-cost devices, this cost can be negligible.