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IPC-5704

Bare Board Cleanliness
IPC-5704 Bare Board CleanlinessThe 
cleanliness of a completed PCB is crucial because a contaminated circuit board deteriorates 
insulation resistance and dielectric strength.

Cleanliness Requirements 
IPC-5704 provides industry guidance on cleanliness testing for both product acceptance and process control, 
ensuring reliable equipment and chemistries.

IPC Standards
"The 
cleanliness of a printed board can directly impact the effectiveness or quality of an assembled 
printed board," explains John Perry, IPC technical project manager. "Residues increase the risk of field 
failures or can electrically impede a printed board's function, so having acceptance criteria for various 
levels of testing as well as direction on how many samples should be tested is extremely important."

C-7000 for Unpopulated Circuit Boards
The cleanliness provisions for 
IPC-5704 have been adapted from Delphi's C-7000. A bare board specification based on ion chromatography, C-7000 has been successfully used for 10-15 years and is consistent with recommended cleanliness levels from CSL/Foresite, PAL, and Rockwell Collins. 

Ion Chromatography
Like the industry standard Ionograph, Ion Chromatography measures total 
ionic contamination. However, and unlike an Ionograph, Ion Chromatography provides a breakdown of the levels of each individual component of ionic contamination

Process Solutions for High-Reliability Applications
Providing solutions for 
Printed Circuit Boards with High-Reliability Applications means accommodating the enhanced specification required. As a result, we employed a multi-step process adjustment to ensure bare board cleanliness

A primary contributor to high 
ionic contamination levels is the flux used in the HASL process, which can become entrapped in soldermask pores. 

UV Bumping
To close these pores, Saturn installed a UV oven in line with our soldermask developing and baking line. The UV "bumping" completes the soldermask cross-linking process to close the pores--ensuring the flux remains free on the PCB surface and no longer entrapped within the soldermask.

Custom Post-HASL Cleaning Line...On Steroids!
Saturn designed and built a custom post-HASL cleaning line for the sole purpose of removing the flux from the board's surface.

Simply put, it's an industry-standard post-cleaner on steroids. 

Comparison Chart Provides Breakdown...Even if Industry Doesn't
Below is a chart comparing the industry-standard to Saturn's custom-built post-HASL cleaner.