Source: Fresh Date ClassroomOriginal Author: Xiaozao JunIn our daily work and life, we often use various electronic or electrical products, such as computers, mobile phones, televisions, refrigerators, washing machines, etc.If we take these products apart, we will see a green board similar to the one below.
Sometimes it’s blue or black.Everyone knows that this green board is called a circuit board. A more official name is printed circuit board, or PCB (Printed Circuit Board; sometimes referred to as PWB, Printed Wire Board, abroad).On the PCB, many electronic components are soldered, such as capacitors, resistors, inductors, etc.We can also see some black square components.That’s right, this component is likely a chip (referred to as a chip in English).
Definition of Chip
A chip is actually a rather general term.For electronic devices, it is hidden inside and very important, equivalent to an engine in a car or a heart in a person, hence the name “core”. In terms of shape, it comes in pieces, so it’s called a “chip”. Together, it becomes “chip”.Generally speaking, a chip is an integrated circuit (integrated circuit). The two can be equated and used interchangeably.Integrated circuits are relatively easy to define. Through specific technologies, transistors, resistors, capacitors, diodes, and other electronic components are integrated onto a single substrate to form a micro circuit, which is called an integrated circuit.If this substrate is made of semiconductor materials (such as silicon), or if the integrated circuit is made from semiconductor material wafers, it belongs to semiconductor integrated circuits.What we traditionally refer to as integrated circuits basically refers to semiconductor integrated circuits. Therefore, sometimes the terms semiconductor, chip, and integrated circuit are often used interchangeably.If we delve deeper, there are still some differences between chips and integrated circuits.Some industry perspectives believe:Integrated circuits are circuits, the basic unit, mainly emphasizing the realization of a certain function, such as a certain logical operation. In circuit design and other scenarios, this term will be used more.On the other hand, a chip is a more macro and productized concept. After design, manufacturing, packaging, and testing, it forms a directly usable product form, which is considered a chip. When emphasizing usage, people will more often use the term “chip”, such as CPU chip, AI chip, baseband chip, etc.Some also define a chip as: “a general semiconductor component product that contains one or more integrated circuits and can achieve a specific function”. In other words, a chip is a generic term for semiconductor component products.In contrast, the distinction between semiconductors and integrated circuits is clearer:Semiconductors include: integrated circuits + discrete devices + optoelectronic devices + sensors.The main distinction between integrated circuits and the other three is the level of integration. The number of transistors in an integrated circuit far exceeds that of discrete devices, optoelectronic devices, and sensors. Additionally, the substrate materials are generally different.Currently, the combined market size of optoelectronic devices, discrete devices, and sensors only accounts for about 10% of the total semiconductor market size.Thus, we can say: integrated circuits are the most important component of semiconductors.
Classification of Chips
A chip is a set of circuits that achieve specific functions. It has a modular feature that allows manufacturers to quickly design and develop products, reducing development difficulty and shortening development cycles.For decades, semiconductor technology has rapidly developed under the guidance of Moore’s Law, with chip sizes becoming smaller and accommodating more circuits, significantly reducing the size, cost, and power consumption of electronic products.It has not only improved our quality of life but has also led the information technology revolution, promoting the progress of human civilization.
With chips, we have mobile phones.Today, chips have a very wide range of applications and have spawned many categories.The World Semiconductor Trade Statistics (WSTS) classification method is quite authoritative and official. They categorize all integrated circuit types into: Analog, Micro, Logic, and Memory.On an unofficial level, the classification is more arbitrary.By function, we often classify chips into: computing chips, storage chips, communication chips, sensing chips, energy chips, and interface chips.Some familiar types of chips include:
By design concept, they can also be divided into general-purpose chips (CPU, GPU, etc.) and dedicated chips (ASIC).We can also classify them by process technology, such as the commonly heard 28nm, 14nm, 7nm, 5nm. Or, by semiconductor materials, such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), gallium nitride (GaN), etc. We will introduce these when discussing the chip manufacturing process later.
In fact, besides electrical chips, we have also developed optical chips (such as silicon photonics technology), using light instead of current to transmit signals.From the perspective of integrated circuits, there are many classifications.By manufacturing process, integrated circuits can be divided into semiconductor integrated circuits and film integrated circuits (film integrated circuits use metals and ceramics, etc.). Film integrated circuits can be further divided into thick-film integrated circuits and thin-film integrated circuits.
By circuit properties, we can also classify them into digital integrated circuits, analog integrated circuits, and mixed-signal integrated circuits.Digital integrated circuits, as the name implies, process digital signals. They are the most common around us, such as microprocessors (CPU, GPU, etc.), digital signal processors (DSP), and microcontrollers (MCU), all of which are digital integrated circuits.Analog integrated circuits are mainly used for amplifying, filtering, demodulating, and mixing analog signals, often used in sensors, power chips, operational amplifiers, etc.Mixed-signal integrated circuits integrate both analog and digital circuits on a single chip. As you might guess, analog-to-digital (ADC) and digital-to-analog (DAC) conversion chips belong to this category.By the number of microelectronic devices integrated on the chip (scale), integrated circuits can be classified as follows:
More professionally, by conductivity type, integrated circuits can be divided into bipolar integrated circuits and unipolar integrated circuits.Bipolar integrated circuits have complex manufacturing processes and higher power consumption, with representative integrated circuits including TTL, ECL, HTL, LST-TL, STTL, etc.Unipolar integrated circuits have simpler manufacturing processes, lower power consumption, and are easier to produce large-scale integrated circuits, with representative integrated circuits including CMOS, NMOS, PMOS, etc.The above terms will be explained in detail by Xiaozao Jun when introducing the working principles of chips later.
Internal Structure of Chips
Earlier, we mentioned that chips appear as black square plates.Sometimes, they also have silver metallic covers (for enhanced protection and better heat dissipation). For example, our CPU:
CPU Cover
Appearance of CPUA chip becomes like this after packaging (a step in the chip manufacturing process).We can only see the core of the chip by removing the “shell”. Under a microscope, it looks like this:
The outer circle is the pins. The thin lines are the leads. The square part in the middle is the actual circuit of the chip.If we zoom in further, it looks like this:
In 3D effect, it looks like this:
Indeed, they are three-dimensional, with many layers, densely packed, resembling a super maze, also like a futuristic city.In the image, each line is a connection. The objects they connect to are transistors.The number of transistors in a chip usually represents the capability of that chip. The more transistors, the more circuits, and the stronger the functions and computing power. Nowadays, many manufacturers emphasize how many transistors a chip has, which is what this means.
NVIDIA’s H100 GPU has 80 billion transistors.Chips can be simple (relatively speaking) or complex. Some complex chips can also be divided into different functional modules. These modules together form a system, becoming a SoC (System on Chip).Our mobile phone main chips, such as Qualcomm Snapdragon, MediaTek Dimensity, and Huawei Kirin, are typical SoC chips. The chip includes CPU, GPU, APU, ISP, baseband, RF, etc.
END
Reprinted content represents the author’s views only
It does not represent the position of the Institute of Semiconductors, Chinese Academy of Sciences
Editor: Yi Er
Responsible Editor: Liu Kuai Qian De Yu
Submission Email: [email protected]
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