AMB Ceramic PCB

What is AMB  Ceramics PCB?

AMB(Active Metal Brazing Substrate) is the further development of DBC technology. It is a method to use a small amount of active elements such as Ti and Zr contained in the filler metal to react with ceramics to form a reaction layer that can be wetted by liquid solder, so as to realize the bonding between ceramics and metals. AMB is combined by chemical reaction between ceramic and active metal solder at high temperature, so its bonding strength is higher and its reliability is better.

AMB technology refers to a process technology in which AgCu solder containing active elements Ti and Zr wets and reacts at the interface between ceramics and metals at a high temperature of about 800°C, thereby realizing heterogeneous bonding of ceramics and metals.In terms of performance, the bonding in the AMB ceramic substrate is achieved through the chemical reaction of the ceramic and the active metal solder at temperature, and the Si3N4 ceramic used in the AMB has a higher thermal conductivity than the traditional Al2O3 ceramic substrate (>90W/mK 25℃), closer to the thermal expansion coefficient of silicon (2.6×10 -6 /K), therefore, AMB substrates have higher bonding strength and reliability.

Combined with silver sintering process and high-power silicon carbide chip, the AMB copper layer with active metal coating can achieve high power, better heat dissipation and high reliability packaged modules (can withstand 3000 thermal shocks), AMB ceramic substrates have higher bonding strength and cold and thermal cycling characteristics and have made progress in applications such as high-power semiconductor modules, high-frequency switches, wind power generation, new energy vehicles, power locomotives, and aerospace.

The difference between DBC and AMB products is mainly reflected in the process technology: First, the copper and ceramics of DBC products are directly bonded, while the copper and ceramics of AMB products are brazed with active metal solder, which requires an additional silk screen process . Before brazing, the active metal solder needs to be evenly placed on the ceramic substrate;AMB Ceramic PCB bonds (brazes) copper directly to a ceramic substrate under high temperature vacuum. The brazing technique can also achieve copper weights up to 800μm on thin ceramic substrates. These heavy copper materials make AMBs ideal for power electronics. secondly, the copper of the DBC product is formed by one etching, while for the AMB product with an additional metal brazing layer, an additional Solder is removed by an etching process, usually with hydrofluoric acid.

AMB Ceramic PCB Manufacturing Processing

According to different brazing materials, the AMB Ceramic PCB process is currently divided into two types: placing silver-copper-titanium solder sheets and printing silver-copper-titanium solder paste.

The process flow of Si3N4 AMB Ceramic PCB printing silver copper titanium solder paste is shown in the figure below. First, Ag, Cu, and Ti elements are directly mixed in the form of powder to make a slurry, and the Ag-Cu-Ti solder is printed on the silicon nitride ceramic substrate by screen printing technology, and then the copper foil is laminated on the silicon nitride ceramic substrate by hot pressing technology. On the solder, a silicon nitride AMB copper clad laminate that meets the requirements is finally prepared through sintering, photolithography, corrosion and Ni plating processes.

Ag-based powder and its solder paste products for AMB ceramic circuit boards have the characteristics of low oxygen content, high purity and high sphericity. The following is a comparison of AIN Ceramic PCB processing between DBC and AMB.

AMB Ceramic PCB Advantages

(1) Good thermal cycle, good metal bonding, strong weldability and longer service life;

(2) The thermal cycles number of AMB ceramic PCB is 500~5000 times. The number of thermal cycles AMB AIN  ceramic substrateis more than 1000 times, and the number of thermal cycles of Si₃N₄ ceramic substrate is more than 5000 times, with better heat resistance and longer service life; the metal bonding force is above 28n/mm, and the metal layer bonding force is strong.

(3) The ceramic matrix prepared by the AMB process is a high-temperature metallurgical combination of AIN and oxygen-free copper through metal solder. AMB Ceramic circuit board has the advantages of high bonding strength, good reliability in cold and hot cycles, higher thermal conductivity, better copper layer bonding, and also has the advantages of smaller thermal resistance and higher reliability. The expansion coefficient is low, the expansion coefficient is close to that of silicon, and it is widely used in high-power packaging and IGBT electronic packaging.

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Please contact us for customization. We can also supply Aluminum Nitride (AlN) Ceramic with thermal conductivity up to 230W/mK

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QFPCB has 15 years of experience in the field of AMB Ceramic PCB production, choose QFPCB, you will get a reliable supplier in China. Contact us today for your AMB ceramic solutions.