Active Metal Brazing AMB

The process flow for active metal braze substrates usually involves coating the braze alloy on the ceramic substrate of interest in a paste form, or as a metal foil. The copper foil is then placed on top of the braze alloy, and the whole assembly is heated in an inert atmosphere. The braze alloy melts and forms a strong bond with the copper and substrate. In many cases, the braze alloy and copper are patterned before bonding to eliminate the need for 

Alternatively, a complete coahng of braze alloy and copper foil can be placed on the ceramic. In this case, the copper is then etched much like a DEC substrate. However, in this case, an etching or abrasion process must be used to remove the unwanted braze alloy and activated substrate layer. 

Manufacturing infrastructure — high volume Rework tolerance X X X X X X X X X  

Note X Indicates ceramic offers significant advantage to the market/application. 

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Active metal brazing (AMB) is a process to braze metals, such as Kovar , titanium, copper, and molybdenum, to ceramics. The process does not require a metallization on the ceramic. For this chapter, only copper brazing will be addressed. The AMB process is used by some manufacturers as an alternative to DBC as it provides higher adhesive strength while using a less critical furnace profile. It also does not rely on oxide formation as in the DBC process. 

There are three fundamental methods of metallizing ceramic suhstrates thick film, thin film, and copper, which includes direct bond copper (DEC), plated copper, and active metal braze (AMB). Not all of these proeesses are compatible with all suhstrates. The selection of a metallization system depends on both the application and the eompatihility with the substrate material. 

Because the AMB process uses copper sheets as the metallization, the electrical and thermal performances are identical to that of DEC. It should be noted that the ceramic interaction with the active metal in the braze material has a high thermal conductivity and can be neglected in most thermal analyses. 

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