-
- News
- Books
Featured Books
- smt007 Magazine
Latest Issues
Current IssueIPC APEX EXPO 2024 Pre-show
This month’s issue devotes its pages to a comprehensive preview of the IPC APEX EXPO 2024 event. Whether your role is technical or business, if you're new-to-the-industry or seasoned veteran, you'll find value throughout this program.
Boost Your Sales
Every part of your business can be evaluated as a process, including your sales funnel. Optimizing your selling process requires a coordinated effort between marketing and sales. In this issue, industry experts in marketing and sales offer their best advice on how to boost your sales efforts.
The Cost of Rework
In this issue, we investigate rework's current state of the art. What are the root causes and how are they resolved? What is the financial impact of rework, and is it possible to eliminate it entirely without sacrificing your yields?
- Articles
- Columns
Search Console
- Links
- Events
||| MENU - smt007 Magazine
The War on Soldering Defects under Area Array Packages: Head-in-Pillow and Non-Wet Open
August 17, 2015 | Jason Fullerton, AlphaEstimated reading time: 2 minutes
The most difficult aspect of any soldering defect on an area array package is the inability to observe the defect easily. It is important to understand the characteristics of soldering defects in order to identify the proper action to take to mitigate the defects in a soldering process.
Head-in-pillow (HiP) defects are soldering defects on area array packages characterized by a lack of coalescence between the solder paste deposit and the package solder bump. In these defects, the solder paste deposit coalesces properly with itself and typically wets to the PCB land. Displacement of each solder deposit (paste and bump) is a common feature of HiP defects.
Non-wet open (NWO) defects are soldering defects characterized by a lack of wetting to a PCB land by a fully coalesced solder deposit on an area array package. In this defect, the solder paste and the package solder bump coalesce together fully without wetting to the PCB land.
A spherical or nearly spherical shape along the PCB side of the bump is a common feature of NWO defects.
What Head-in-Pillow and Non-Wet Open are not
It is important to discuss defects that can share some symptoms with HiP and NWO, in order to contrast against defects that require different mitigation actions. One example of a defect with similar symptoms to HiP and NWO is insufficient solder paste volume transfer during printing. In this case, it can appear that no wetting has occurred to the land and mimic NWO (especially if no paste has been transferred). If a small amount of paste has been printed, the resulting connection can initially appear to be consistent with HiP. Troubleshooting of HiP and NWO defects should include steps to ensure the solder paste printing process is properly controlled and performing well.
Another defect that can be confused with HiP is cold solder, which is characterized by a lack of coalescence of the solder paste deposit. HiP is a defect that occurs in the presence of a well-defined and controlled reflow process, which ensures coalescence of the solder paste deposit. Diagnosis of a defect as HiP should include an examination of the reflow profile to ensure that the process is not at risk of causing the occurrence of cold solder.
Non-wetting to a PCB land has many causes that should be familiar to most with experience troubleshooting solder defects. These defects can easily be confused with NWO since both defects share a symptom: poor wetting of a coalesced solder bump to the PCB land. The key difference is that NWO defects result in a solder bump that is spherical along the PCB side. A defect that is solely caused by poor PCB solderability will generally demonstrate the same shape as a typical area array solder connection: flatter and wider than a sphere and generally sharing the contour of the land along that interface. Testing the solderability of the PCB lands is an important step when attempting to determine if a wetting defect is a result of NWO defects.
Editor's Note: This article originally appeared in the August 2015 issue of SMT Magazine.
Suggested Items
Indium Corporation to Present, Exhibit at EPP InnovationsFORUM
03/28/2024 | Indium CorporationIndium Corporation is set to present and exhibit at EPP InnovationsFORUM, one of Europe’s premier single-day electronics manufacturing forums, on April 17 in Leinfelden-Echterdingen, Germany. Topic areas for 2024 will include AI, automation, sustainability, and quality.
Reducing Nitrogen Consumption in Convection Soldering with Rehm Thermal Systems' Patented Mechatronic Curtain
03/28/2024 | Rehm Thermal SystemsCurrent developments indicate a need for larger throughput heights due to the trend towards e-mobility, which in turn increases nitrogen consumption for process inertization. Rehm Thermal Systems responds to this issue with an innovative solution: the mechatronic curtain.
Indium Corporation, Industry Partners to Showcase Products “Live@APEX”
03/26/2024 | Indium CorporationIndium Corporation®, in cooperation with its industry partners, will feature its proven solder solutions live on the show floor throughout IPC APEX Expo from Apr. 9‒11 in Anaheim, Calif., U.S.
ITW EAE Wins New Product Introduction Award for Electrovert® Wave Soldering Machine Deep Wave
03/26/2024 | ITW EAEITW EAE is proud to announce that it has earned a 2024 New Product Introduction (NPI) Award for Electrovert’s Deep Wave option for wave soldering machines. This new, innovative system provides the ability to pump up to a 20 mm wave height.
Mek's Next-Gen AOI Technology Takes Center Stage at IPC APEX EXPO 2024
03/19/2024 | MEKMek is excited to announce its presence at IPC APEX EXPO, North America's largest electronics manufacturing event, in Anaheim, California, from April 6-11, 2024. Attendees are invited to visit Mek at booth #1433 to explore the latest AOI technology offerings.