Symposium Conference Proceedings

The Development of a 0.3mm Pitch CSP Assembly Process Part 2: Assembly & Reliability

Authors: Mark Whitmore and Jeff Schake
Company: ASM Assembly Systems
Date Published: 4/12/2016   Conference: Symposium

Abstract: With shrinking component technology the stencil printing process is becoming increasingly challenged. Not only do long established design rules need to be broken to accommodate finer pitches, but print quality and consistency of print are becoming even more critical to maintain a high yield assembly process.

A major study has been undertaken looking at several different aspects of the stencil printing process and their impact upon the assembly and reliability of 0.3mm pitch CSP components.

Previously, in Part 1, stencil printing factors such as aperture design (circles, rotated squares), aperture size (140 microns thru 200 microns) and printing technology (standard squeegees, active squeegees) were investigated. Highlights of the experiments are summarised here (whilst full details can be found in the 2015 conference proceedings of SMTA South East Asia [1] and SMTA ICSR [2]).

Key learnings from Part 1 have subsequently been used for a series of assembly trials to determine the impact, (if any) of the stencil printing process on ultimate solder joint reliability of 0.3 mm pitch CSP assemblies. Assembly yields in terms of electrical continuity and identification of shorted solder bumps are reported here, together with preliminary reliability data from ongoing thermal cycling of assemblies.

Members download articles for free:

Not a member yet?

What else do you get when you join SMTA? Read about all of the benefits that go along with membership.

Notice: Sharing of articles is restricted to just your immediate work group. Downloaded papers should not be stored on an external network or shared on the internet.


SMTA Headquarters
6600 City West Parkway, Suite 300
Eden Prairie, MN 55344 USA

Phone +1 952.920.7682
Fax +1 952.926.1819