Impractical Stencil Aperture Designs to Enable M0201 Assembly
Effectiveness of I/O Stencil Aperture Modifications on BTC Void Reduction
Microalloyed Sn-Cu Pb-Free Solder for High Temp
Selective Reflow Rework Process
Impact of Thermal Loading on the Structural Intergrity of 3D TSV Package
Design and Fabrication of Ultra-Thin Flexible Substrate
Influence of PCB Surface Features on BGA Assembly Yield
Last Will and Testament of the BGA Void
Latest Industry News
Print These Electronic Circuits Directly Onto Skin
Compal increasingly asked to diversify production bases
Intel's margins tumble as customers shift to cheaper chips, shares slide 10%
From Foldable Phones to Stretchy Screens
6 Considerations for Integrating Sensors in Vehicles
Bill Gates Says Unhappy Customers Are Good for Your Business. Here's Why.
iPhone 12 review: Upgrade for the camera, not 5G
Apple's shifting supply chain creates boomtowns in rural Vietnam

Generalizations About Component Flatness

Generalizations About Component Flatness
Failure to have completely flat components and circuit boards can lead to opens, shorts, head on pillow, weakened solder joints and stressed solder joints.
Analysis Lab


Authored By:

Bev Christian, Linda Galvis, Rick Shelley and Matthew Anthony
Cambridge, Ontario, CANADA


An examination was made of a database of collected component warpage information in the hopes of finding a simple correlation between a physical attribute of the components and the warpage measured at reflow temperatures. This would allow companies to by-pass actual experimentation, at least for a first pass approximation of the expected warpage.

The measured flatness information was compared to various component outer and inner dimensions. In specific instances some correlations have been discerned, but no over-arching generalization can be made.


In this paper an examination has been made of over 250 different components that have been examined using shadow moie. There is no one attribute that provides a perfectly linear, exponential or polynomial correlation with the warpage observed for all plastic encapsulated components examined.

For various subsets of the components tested, correlations have been possible with respect to component thickness, substrate thickness, total volume of the ICs in the component or IC die thickness when there was only one die. There were factors that could not be taken into consideration because of lack of data.

Some of these were: packaging house or houses used by each component manufacturer, particular epoxy used for each component and curing conditions for each epoxy. It is expected that the type of epoxy would be the most important of these three mentioned.

Certainly component thickness and even more so IC volume are important considerations when examining for component flatness. But, as the scrutiny given to the data presented here shows, neither dimension tells the whole story regarding the warpage of components.

Initially Published in the SMTA Proceedings


No comments have been submitted to date.

Submit A Comment

Comments are reviewed prior to posting. You must include your full name to have your comments posted. We will not post your email address.

Your Name

Your Company
Your E-mail

Your Country
Your Comments

Board Talk
Causes of Blowholes
Tips When Moving a Reflow Oven
Assembling Boards with BGAs on Both Sides
Larger Stencil Apertures and Type 4 Paste
5 vs 8-Zone Ovens
Component Moisture Question?
BGA Components and Coplanarity
How To Verify Cleanliness After Rework and Prior to Re-coating?
Ask the Experts
Initial Screen Print Test Board
HASL Surface Finish and Coplanarity
Legend Marking Discoloration
Cleanliness Testing
Stencil Cleaning Frequency
Exposed Copper Risk
Spotting After DI Water Cleaning
ESD Grounding - 1 Meg Ohm Resistor