Assembly and Rework of Lead Free Package on Package Technology

Authors: Raymond G. Clark and Joseph D. Poole

Abstract: Miniaturization continues to be a driving force in both integrated circuit packaging and printed circuit board laminate
technology. In addition to decreasing component pitch (lead to lead spacing), utilization of the vertical space by stack Save ing
packages has found wide acceptance by both designers and manufactures of electronics alike. Lead free Package on Package
(PoP) technology represents one of the latest advancements in vertical electronics packaging integration and has become the
preferred technology for mobile hand held electronics applications. TT Electronics in Perry, Ohio has developed the capability
to assemble and rework numerous “state of the art” packaging technologies. This paper will focus on the essential
engineering development activities performed to demonstrate TT Electronics’ ability to both assemble and rework PoP
components.

Printing and Assembly Challenges for Quad Flat No-Lead Packages

Author: William E. Coleman, Ph.D.

Abstract: QFNs present several assembly problems. The QFN can float during reflow if there is too much solder. Aperture size is a problem because with aperture widths as low as 0.175mm and aperture lengths as low as 0.4mm there can be a problem with the percent of paste transfer. Another challenge is the type of solder mask that’s employed on the printed circuit board. The article explores three types of solder mask designs – SMD where the pad opening on the board is defined by the solder mask; NSMD, where the pad itself defines the boundary of the pad and the solder mask is pulled back off the pad (typically 0.05 to 0.075mm per side); and NSMD–Window – and gives stencil design considerations and guidelines for each type. QFN repair is also covered. It  shows how with proper stencil design, proper stencil technology selection (laser, electroform, and nano-coat), and proper PCB solder mask layout, the challenges that quad flat no-lead packages (QFNs) present to the assembly process can be overcome.

Released September 2012

http://www.photostencil.com/pdf/Mastering-QFN-Challenges.pdf

Two Worlds Converging: Chipshooting and Flip-chip Bonding

By Eric Klaver and Patrick Huberts

Pick-and-place equipment has over the years mostly evolved in four key areas; it is faster, more reliable, more accurate and more user friendly. Most pick & place vendors have aimed at the mass production market, while others have moved towards more dedicated markets – mostly where production flexibility is needed as with high-mix, prototyping or evaluation. But in the end, we’re all doing the same thing: picking and placing components on bare substrates.

3 pages.

New Product Introduction

By ASM Siplace

New product introductions (NPIs) involve complex processes. This new publication presents solutions for everyday challenges, lots of tips and tricks, and a convenient checklist for the NPI process. It is directed toward manufacturers who want to implement robust NPI processes in their high-mix electronics production environments with consistent tool chains in order to raise the efficiency and quality of their new product introductions, which occur with increasing frequency. Readers will learn how even the first yield can be produced efficiently and error-free despite faulty Gerber data, incomplete bills of material, and missing or late component descriptions.