Chips (Integrated Circuits, ICs), packages, and printed circuit boards (PCBs) are closely related in electronic devices, but they have different functions and roles. The detailed design process is shown in the figure below.
1. The Connection Between the Three
Chip and Package: A chip is an integrated electronic component, typically made of semiconductor materials, and contains multiple functional units such as transistors and capacitors. Packaging is the process of enclosing the chip in an outer protective shell to protect it from the external environment and provide pins or balls for connection to external circuits. The most important function of packaging is protection, followed by heat dissipation.
Chip and PCB: After being packaged, the chip is usually mounted on a PCB. A PCB is composed of an insulating substrate and conductive traces, on which various electronic components, including chips, resistors, and capacitors, can be mounted. The chip is mounted on the PCB through soldering or other connection methods and connected to other components or circuits to form a complete electronic system.
2. Differences between the Three
Different Functions and Structures: A chip is an integrated circuit within an electronic device, containing multiple functional units. Packaging is the process of encapsulating the chip in an external protective shell, providing pins or balls for connection to external circuits. A PCB, on the other hand, is a board-like structure used to mount and connect various electronic components.
Different Functions and Roles: A chip is responsible for performing specific functions, such as logical operations and signal processing. Packaging provides protection and connectivity for the chip. A PCB, on the other hand, is used to assemble and connect various electronic components to form a complete electronic system.
3. Four Major Functions of Packaging and Examples
1. Fixed Pin System
For a chip to function properly, it must exchange data with external devices, and this is where packaging plays a crucial role. Of course, it's impossible to connect the pins inside a chip directly to a circuit board, as the metal wires are extremely thin, typically less than 1.5 microns (μm), and often only 1.0 μm. However, after packaging, the external pins are soldered to the internal pins with copper metal, allowing the chip to indirectly connect to the circuit board for data exchange.
External pin systems typically use two different alloys: iron-nickel alloy and copper alloy. The former is used for high strength and stability, while the latter offers better electrical and thermal conductivity. The specific pin system chosen depends on the specific situation.
- Physical Protection
Chips are protected from contamination by particles and other external damage through packaging. The primary method for physical protection is to secure the chip to a specific mounting area and enclose the chip, its connections, and associated pins in an appropriate packaging shell. The level of chip packaging required varies depending on the application, with consumer products typically having the lowest requirements.
3. Enhanced Heat Dissipation
As we all know, all semiconductor products generate heat during operation. When this heat reaches a certain level, it can affect the normal operation of the chip. The various materials of the package itself can dissipate some of this heat. Of course, for most chips that generate a lot of heat, in addition to cooling them with the packaging material, it's also worth considering installing a metal heat sink or fan on the chip to achieve even better heat dissipation.
4. Environmental Protection
Another function of the package is to provide environmental protection for the chip, protecting it from moisture and other gases that could interfere with its normal function and adversely affect its operation.
