Integrated Circuits are semiconductor microdevices originating in the 1950s. Through precision manufacturing processes such as oxidation, photolithography, diffusion, epitaxy, and aluminium deposition, semiconductor elements, resistors, capacitors, and interconnecting conductors are fully integrated onto a miniature silicon wafer. This forms circuits with specific functions, ultimately resulting in soldered and encapsulated electronic microdevices.
Based on product characteristics, integrated circuits can be subdivided into various types such as microprocessors, analogue circuits, logic circuits, and memory devices. Classified by functional implementation and downstream application domains, the ic industry further encompasses communication chips, sensor chips, security chips, memory chips, application processor chips, power management chips, development and control chips, and driver chips. For instance, communication chips are extensively deployed in end devices such as mobile phones, computers, smart home appliances, and smart payment tools. They support wireless and microwave communications. With the proliferation of technologies like Wi-Fi, their market continues to expand, evolving towards miniaturisation, high speed, multifunctionality, and low power consumption.
Although the terms ‘chip’ and ‘integrated circuit’ (IC) are often used interchangeably in everyday discourse, they possess subtle conceptual distinctions. A chip specifically denotes a highly miniaturised electronic component that integrates numerous transistors, capacitors, resistors, inductors, and related circuits to perform specific functions. For instance, the central processing unit (CPU) serving as a computer’s core is a type of chip.
IC, however, emphasise a manufacturing and application technology. By integrating multiple electronic components and circuits onto a single chip, they achieve higher integration levels and smaller physical dimensions. They are typically manufactured using semiconductor processes to ensure high quality and stability. Thus, a chip emphasises the functional entity itself, while an integrated circuit focuses on the manufacturing process and integration method used to realise that functional entity.
IC Chip Classification
Classification by Functional Structure
Integrated circuits can be broadly categorised into two main types based on their function and structure: analogue integrated circuits and digital integrated circuits.
Analogue ics generate, amplify, and process various analogue signals (signals whose amplitude varies continuously over time, such as audio signals in semiconductor radios or tape signals in recorders). Digital integrated circuits generate, amplify, and process various digital signals (signals with discrete values in both time and amplitude, such as audio and video signals reproduced from VCDs or DVDs).
Fundamental analogue ics include operational amplifiers, multipliers, integrated voltage regulators, timers, and signal generators. Digital ics encompass numerous varieties: small-scale integrated circuits feature multiple gate circuits; medium-scale ics include data selectors, encoders/decoders, flip-flops, counters, and registers; large-scale or very large-scale integrated circuits comprise PLDs (programmable logic devices) and ASICs (application-specific integrated circuits).
Classification by Manufacturing Process
ICs may be categorised by manufacturing process into semiconductor ics and thin-film ics. Thin-film ics are further subdivided into thick-film ics and thin-film ics.
Classification by Integration Level
Integrated circuits are classified by scale as: small-scale integrated circuits (SSI), medium-scale integrated circuits (MSI), large-scale integrated circuits (LSI), very large-scale integrated circuits (VLSI), and ultra-large-scale integrated circuits (ULSI).
Classification by Conduction Type
Integrated circuits may be categorised by conduction type into bipolar integrated circuits and unipolar integrated circuits. Bipolar ics involve complex fabrication processes and exhibit higher power consumption; representative types include TTL, ECL, HTL, LST-TL, and STTL. Unipolar integrated circuits feature simpler fabrication processes and lower power consumption, facilitating the production of large-scale integrated circuits; representative types include CMOS, NMOS, and PMOS.
Classification by Application
Integrated circuits can be categorised by application into television ICs, audio ICs, disc player ICs, video recorder ICs, computer (microcomputer) ICs, electronic keyboard ICs, communication ICs, camera ICs, alarm system ICs, and various specialised integrated circuits.
Semiconductor chips, though diminutive in size, possess highly intricate internal structures. This complexity is particularly evident in their core micro-components—tens of thousands of transistors. Integrated circuits primarily comprise the following elements:
- Substrate
Integrated circuits (ICs) typically utilise silicon (Si) wafers as their substrate. This material exhibits excellent semiconductor properties, enabling effective current control. The dimensions and thickness of the silicon wafer are critical in chip design, influencing both performance and manufacturing processes. - Semiconductor Materials
Beyond silicon, modern integrated circuits may utilise other semiconductor materials such as germanium (Ge) or gallium arsenide (GaAs), which offer superior performance in specific applications. - Circuit Interconnections The circuits within an integrated circuit (IC) are formed by connecting various electronic components (such as transistors, resistors, capacitors) via metallic conductors. Aluminium or copper are typically employed for circuit interconnections, forming intricate circuit networks within the IC that transmit signals.
- Logic Gates and Functional Units The fundamental building blocks of integrated circuits (ICs) are logic gates (such as AND gates, OR gates, NOT gates, etc.) and various functional units (e.g., adders, multipliers, memory units, etc.). These basic units work in concert to perform more complex computational and logical processing tasks.
- Packaging Upon completion, integrated circuits (ICs) are packaged into user-friendly forms. Packaging not only protects internal circuits but also provides interfaces for connecting to external devices. Common packaging types include DIP (Dual In-line Package), SOIC (Small Outline Integrated Circuit), and QFN (Quad Flat No-lead Package).
The Role and Functions of Chips
- Data processing chips execute complex computational and data processing tasks. Microprocessors and microcontrollers are the most common types, widely employed in computers, smartphones, and embedded systems.
- Control function chips govern the operation of other electronic components. For instance, microcontrollers are frequently used in household appliances, automobiles, and industrial equipment to monitor and regulate device functioning.
- Storage chips (such as RAM and ROM) are employed to store data and programmes. RAM provides temporary data storage, whilst ROM serves for permanent storage of firmware and system boot programmes.
- Digital Signal Processors (DSPs) specialise in processing audio, video, and other signals, finding extensive application in audio equipment, image processing, and communication systems.
- Communication chips play a pivotal role in wireless communications, including Bluetooth, Wi-Fi, and mobile networks. They handle data encoding, decoding, and transmission.
- Sensing and measurement sensor chips detect environmental changes (such as temperature, humidity, and light levels), converting this information into electrical signals for use by other devices.
- Power management chips regulate and distribute power, ensuring energy efficiency and stability across different operational states of the device.
- Security chips encrypt and decrypt data to safeguard devices and user information, finding extensive application in payment systems and authentication processes.
- Connectivity chips provide various interfaces (such as USB, HDMI, Ethernet) enabling devices to connect with other equipment or networks for data exchange and communication.
- Embedded Applications
Numerous chips are engineered as components within embedded systems, serving specific functions and delivering services across sectors including automotive, medical devices, and smart home technologies.
Integrated circuits, as miniature semiconductor devices, feature intricate and sophisticated internal structures. Utilising silicon wafers as their substrate, they achieve highly integrated electronic functionality through the precise combination of semiconductor materials, circuitry, logic gates, and functional units. These miniature devices play pivotal roles not only in data processing, control, storage, signal processing, communications, sensing and measurement, power management, security functions, and connectivity, but also deliver specialised services and capabilities across diverse embedded applications.
