AN3338 datasheet(39/72 Pages) STMICROELECTRONICS

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AN3338

Package

The SLLIMM benefits from a compact package while providing high power density, the best

thermal performance, and great electrical isolation (> 2500 VRMS).

The SDIP is a dual-in-line transfer mold package, available in 25-lead version (SDIP-25L)

and 38-lead version (SDIP-38L) and based on the state of the art DBC mounting technology

for the power stage, whilst the control stage is assembled on a PCB layer. A vacuum

soldering process is used to avoid any gas inclusion (voids) during the soldering process

that could cause potential hot spots. It results in a further increase in the reliability of the

SLLIMM family due to the improved thermal and electrical conductivity.

This technology makes it possible to achieve extremely low thermal resistance values, high

stability in thermal cycling, small size with optimum cost-effectiveness, and quality level.

3.1

DBC substrate

DBC means direct bonded copper and denotes a process in which copper and a ceramic

material are directly bonded, as shown in

Figure 26. Direct bonded copper substrates have

been proven for many years to be an excellent solution for electrical isolation and thermal

management of high power semiconductor modules.

The advantages of DBC substrates are, firstly, high current-carrying capability, due to thick

copper metallization, and secondly, a thermal expansion coefficient close to the silicon one

at the copper surface.

DBC has two layers of copper that are directly bonded onto an aluminum-oxide (Al2O3)

ceramic base. The DBC process yields a super-thin base and eliminates the need for thick,

heavy copper bases that were used prior to this process. Because SLLIMM with DBC bases

has fewer layers, it has much lower thermal resistance values than those based on different

materials.

Figure 26. DCB structure

AN3338 Datasheet(PDF) 39 Page - STMicroelectronics