Definition and Composition.

• An integrated circuit is a tiny electronic device or component. It is the use of a certain process, the required transistors in a circuit, resistors, capacitors and inductors and other components and wiring interconnect together, fabricated in a small piece or several small pieces of semiconductor wafers or medium substrate, and then packaged in a shell, become a miniature structure with the required circuit function.For example, the central processing unit (CPU) of a computer is a highly complex integrated circuit that integrates hundreds of millions of transistors on a small chip and is capable of performing complex arithmetic and logic operations.
• From the physical structure, integrated circuit is mainly composed of two parts: the chip (die) and the package.From the physical structure, integrated circuit is mainly composed of two parts: the chip (die) and the package. The chip is the core part, which integrates various electronic components and circuits. Packaging plays a role in protecting the chip, providing electrical connection and physical support. Common packaging forms include DIP (dual in-line packaging), QFP (square flat packaging), BGA (ball grid array packaging), etc.

• PCBA refers to the printed circuit board that has completed the assembly process such as installation and welding of electronic components. Printed Circuit Board (PCB) is a carrier that provides electrical connections for electronic components. It has pre-designed conductive lines, pads, vias and so on.PCBA is on the basis of PCB, will be a variety of electronic components (including integrated circuits, resistors, capacitors, inductors, diodes, transistors, etc.) through surface mount technology (SMT) or through hole instrumentation technology (THT) installed on the PCB, and after welding and other processes to form a component.For example, the motherboard of a mobile phone is a typical PCBA, which is equipped with many chips, capacitors, resistors and other components, and the electrical connection between them is realized through the lines on the PCB.
• In terms of composition, PCBA mainly includes PCB and various electronic components installed on it, as well as solder joints and lines connecting these components.

Function:

• Functions are highly integrated. It is able to integrate complex circuit functions in a small chip to achieve specific functions, such as signal processing, storage, control, etc. Take the storage integrated circuit as an example, it can store a large amount of data, ranging from a few KB to several TB, and is used in the memory, flash memory and other devices of the computer to realize the read and write operation of data.
• The performance mainly depends on its internal circuit design and manufacturing process. Advanced manufacturing processes enable integrated circuits with smaller transistor sizes, resulting in higher integration levels, lower power consumption, and faster computing speeds. For example, the integrated circuit fabricated by the 7nm process has better performance and lower power consumption than the integrated circuit fabricated by the 14nm process under the same function.

• Functional diversity. It is the physical realization of a complete electronic system or subsystem, and by combining different electronic components, including integrated circuits, a wide variety of functions can be achieved. For example, a computer motherboard PCBA, it integrates CPU, memory, hard disk interface, graphics card interface and other functional modules, through the cooperation between these modules, to achieve a variety of computer functions. 
• Performance is affected by many factors. In addition to the performance of the selected integrated circuit, the performance of PCBA is closely related to the PCB design (such as line layout, number of layers, electromagnetic compatibility, etc.), the quality of electronic components and installation process (such as welding quality, rationality of component layout, etc.) and other factors. A well-designed PCBA can give full play to the performance of each component and improve the reliability and stability of the whole system.

Manufacturing technique:

1.Integrated circuit manufacturing process

• The manufacturing process is very complex and highly precise. It mainly includes wafer fabrication, lithography, etching, doping, film deposition and other multiple steps. For example, in the lithography process, a high-precision lithography machine needs to be used to transfer the designed circuit pattern to the wafer surface, whose accuracy can reach the nanometer level.
• And each step of the process requires strict control of environmental conditions (such as cleanliness, temperature, humidity, etc.) to ensure the quality and performance of the integrated circuit.Specialized semiconductor manufacturing equipment and clean plants are required. These devices are very expensive, for example, an advanced lithography machine can cost hundreds of millions of dollars. The construction and maintenance cost of clean workshop is also very high, and its internal air cleanliness is required to reach extremely high standards to prevent dust and other impurities from interfering with the integrated circuit manufacturing process.

2.PCBA manufacturing process

• It mainly includes component procurement, printing solder paste (for SMT process), component mounting, welding (including reflow soldering, wave soldering, etc.), testing (such as AOI - automatic optical inspection, ICT - online circuit testing) and other links. For example, in the component mounting process, it is necessary to use a high-precision mounting machine to accurately place the electronic components to the corresponding pad position on the PCB. The speed and accuracy of the mounting machine have a great impact on the production efficiency and product quality.
• Compared with integrated circuit manufacturing, the equipment cost of PCBA manufacturing is lower and the environmental requirements are not so harsh, but it also requires certain production sites and equipment to complete the assembly and welding of components.

Application scenarios:

1.Integrated circuit

• Widely used in almost all electronic equipment, is the core of modern electronic technology. In the field of computer, CPU, GPU and other integrated circuits are the key factors of computer performance. In the field of communication, baseband chips and RF chips are used in communication devices such as mobile phones and base stations to realize signal processing and transmission. In the field of consumer electronics, such as smart watches, digital cameras and other devices are also inseparable from various functions of integrated circuits, such as sensor chips, image processor chips, etc.

2.PCBA

• The application scenario is mainly as the core motherboard or functional module of electronic devices. For example, in industrial automation equipment, PCBA is used to control the drive of motors, data acquisition and processing of sensors, etc. In medical equipment, such as electrocardiogram instrument, ultrasonic diagnostic instrument and other devices, the motherboard is also PCBA, which realizes the various function control and signal processing of the device.