2019-BTU-web-Vacuum-reflow-Dimock.pdf - 第4页

Voiding is of particular concern for Thermal management of QFN and other devices All about keeping the chip cool by eliminating voids in Thermal Pads because empty spaces don’t transfer heat V oid issues

Outline

 Voids

 Why inline Vacuum Reflow?

 The Inline Vacuum Reflow Oven.

 The Vacuum Reflow Cycle?

 The Vacuum Trial

 The test vehicle

 Preliminary results from an extended trial at the

Universal Advanced Process Lab

 Things to Consider

Voiding is of particular concern for

Thermal management of QFN and other devices

All about keeping the chip cool by eliminating voids in

Thermal Pads because empty spaces don’t transfer heat

Void issues

• Voids form for many reasons including:

▫Paste solvent volatilization

▫Paste solids volatilization

▫Oxide volatilization

▫Outgassing (PCB, Component)

Void formation and growth

• Voids grow by merging

• Then escape the solder if they contact an

exposed surface.