Void Reduction in Bottom Terminated Components Using Vacuum Assisted Reflow - 第17页

Intr oduction ■ Several well known reflow profile process based techniques to reduce voiding – Reflow Profile – Peak Temperature – Time Above Liquidus ■ None of them eliminate voiding ■ Study performed with Vacuum during…

Void Reduction in Bottom Terminated Components

Using Vacuum Assisted Reflow

M. Holtzer[2], M. Barnes[1], D.W. Lee[1], D. Heller[1], T. Cucu[2], J.

Fudala[3], J. Renda[3],

[1] Heller Industries

[2] Alpha Assembly Solutions

[3] MacDermid Enthone Electronic Solutions

Introduction

■ Several well known reflow profile process based techniques to reduce voiding

– Reflow Profile

– Peak Temperature

– Time Above Liquidus

■ None of them eliminate voiding

■ Study performed with Vacuum during reflow

■ High voiding paste/powder

■ 4 Surface Finishes, 2 vacuum pressures, 2 dwell times

■ Full factorial DOE using X-Ray inspection as response

• Single lot of in house voiding test vehicle was used.

• 6 Were finished with an OSP, 6 With Immersion Silver, 6 with

Immersion Tin, 6 with ENIG within a day or two of each other.

•

Paste applied using a 100 µ thick uncoated SS stencil