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Talking about the metal substrate of PCB circuit board
2021-09-09
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Author:Aure

Talking about the metal substrate of PCB circuit board

The times are developing and technology is advancing. Nowadays, black technologies such as unmanned driving, smart home, and smart wear are constantly emerging around us, and the core components of these products include circuit boards. The PCB circuit board products currently on the market are divided into three main categories from the material categories: ordinary substrates, metal substrates and ceramic substrates. Today I want to share with you the metal substrate.


1. Classification of metal substrates:


       There are three main types of metal substrates: aluminum substrates, copper substrates, and iron substrates. Iron substrates are rarely used in the market, and the focus is on aluminum substrates and copper substrates.

Talking about the metal substrate of PCB circuit board

       Aluminum substrate is a unique metal-based copper clad laminate with good thermal conductivity, electrical insulation properties and mechanical processing properties. Aluminum substrates are currently the most used substrates among metal substrates, and aluminum substrates have a thermal conductivity 10 times higher than epoxy substrates. Aluminum substrates are divided into flexible aluminum substrates, mixed aluminum aluminum substrates, multilayer aluminum substrates, and through-hole aluminum substrates.


       Copper substrate is the most expensive kind of metal substrate. The heat conduction effect is many times better than that of aluminum substrate and iron substrate. The circuit layer requires a large current-carrying capacity, so thicker copper foil should be used, the thickness is generally 35μm~ 280μm; Copper substrates are divided into gold-plated copper substrates, silver-plated copper substrates, tin-sprayed copper substrates, and oxidation-resistant copper substrates.


2. Advantages of metal substrate:

       Metal substrates have been used since the 1960s, and were widely used in countries around the world in the 1980s and 1990s. It is estimated that the annual output value of global metal-based printing is about 2 billion U.S. dollars. What makes metal printed boards popular?


1. Thermal expansion


       Thermal expansion and contraction are the common nature of materials, and different materials have different coefficients of thermal expansion. The metal substrate can effectively solve the heat dissipation problem, thereby alleviating the thermal expansion and contraction of different substances on the circuit board, and improving the durability and reliability of the whole machine and electronic equipment.


2. Heat dissipation


       At present, many double-sided and multi-layer boards have high density and high power, and it is difficult to dissipate heat. Conventional circuit board substrates such as FR4 and CEM3 are poor thermal conductors, with interlayer insulation, and heat cannot be dissipated, resulting in high-temperature failure of electronic components. Metal-based printed boards can solve this heat dissipation problem.


3. Dimensional stability


       The size of the metal substrate is obviously much more stable than that of the insulating material. Aluminum-based printed boards and aluminum sandwich panels are heated from 30°C to 140~150°C, with a size change of 2.5~3.0%.


4. Wide range of applications


       The iron substrate has a shielding effect, can replace brittle ceramic substrates, replace components such as radiators, improve the heat resistance and physical properties of the product, and reduce production costs and labor.


       Aluminum substrates and copper substrates are widely used in various fields.


The application of aluminum substrates is very wide, such as audio equipment input, output amplifiers, balance amplifiers; computer CPU boards, floppy disk drives, power supply devices; automotive electronic regulators, igniters, power controllers; LED lights for lighting fixtures, etc. All use aluminum substrates.


Copper substrate is one of the more expensive metal substrates; compared with aluminum substrate, because the material is relatively special, the heat dissipation is relatively good, so it is relatively more expensive in terms of price, mainly suitable for high-frequency circuits and high-frequency circuits. Areas with large changes in low temperature and heat dissipation of precision communication equipment and architectural decoration industries.