Sep05
Using 2D X-Ray to Diagnose BGA Solder Void Issues

post on September 5, 2024

Using 2D X-Ray to Diagnose BGA Solder Void Issues

This is an X-ray inspection image of an MCU’s BGA soldering that failed after reflow. The owner mentioned that the BGA package was not functioning, but when pressing on the MCU, it would temporarily work again. Since Workingbear didn’t have the chance to see the faulty product in person, the assessment is based on this image alone. However, from the overall description given, this appears to be a typical case of BGA non-wetted. Can you spot the problem with the solder balls from the X-ray image above?

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Quality, SMT, Soldering, Test/Inspection     WorkingBear    Views (1,834)     comment (0)
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Aug29
How to Use 2D X-Ray to Identify BGA Issues like Non-Wetting, Cold Solder, and HIP or NWO

post on August 29, 2024

How to Use 2D X-Ray to Identify BGA Issues like Non-Wetting, Cold Solder, and HIP or NWO

If you’re an SMT engineer, you’ve probably used an X-Ray inspection machine to check the soldering quality of BGAs. But, after looking at the BGA solder balls repeatedly, they all seem to look the same. So, how can you tell if there’s a non-wetting issue?

Most people use X-Ray inspection machines to check for issues like solder shorts, insufficient solder, or bubbles/voids. However, using X-Ray to determine if BGA solder balls have non-wetting issues is a bit more challenging, especially with a 2D X-Ray machine. But if you’re careful, you can still find clues using 2D X-Ray images to determine if BGA solder balls have voids.

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Quality, SMT, Soldering, Test/Inspection     WorkingBear    Views (2,428)     comment (0)
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Aug22
What is ENIG Surface Finished for Circuit Boards? What Are Its Advantages and Disadvantages?

post on August 22, 2024

What is ENIG Surface Treatment for Circuit Boards? What Are Its Advantages and Disadvantages?

ENIG (Electroless Nickel Immersion Gold), also known as immersion gold (Au), chemical Ni/Au, or soft gold, is a type of surface finished for printed circuit boards (PCBs). It is widely used in the assembly of mobile phone circuit boards and some BGA package substrates may also use ENIG or NEPIG (Chemical Nickel Palladium Gold).

ENIG is easy to recognize by appearance. If you see a printed circuit board with gold-colored pads (as shown in the image at the beginning of the article), it is likely ENIG. There is another type of “electroplated nickel gold” PCB that also has gold-colored pads, but due to the high cost of gold, it is rarely used unless there is a special need for a thicker gold layer or hard gold.

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PCB/FPC/PTF, Process, Quality, SMT, Soldering     WorkingBear    Views (2,382)     comment (0)
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Aug15
Causes of Poor Solderability on HASL Finished PCBs (Data Collection and Analysis)

post on August 15, 2024

Causes of Poor Solderability on HASL Finished PCBs

Workingbear personally doesn’t recommend using HASL (Hot Air Solder Leveling) surface-finished PCBs in today’s SMT reflow processes, especially for double-sided reflow or fine-pitch components located on 2nd side. The defect rate of soldering with HASL is quite high and hard to overcome.

Most people experienced with SMT processes, when facing issues with SMD components not soldering well, typically first suspect issues with solder paste printing (like improper stencil thickness, aperture, pressure adjustments), solder paste oxidation due to prolonged air exposure, moisture or oxidation on SMD component leads, or incorrect reflow oven temperature profiles.

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PCB/FPC/PTF, Process, Quality, SMT, Soldering     WorkingBear    Views (1,471)     comment (0)

Aug08
What Do PCB and PCBA Stand For? What’s the Difference?

post on August 8, 2024

What is the difference between PCB and PCBA? This should be an easy concept to understand, but since someone asked Workingbear, let’s explain it a bit. If you find any errors while passing by, please let us know to correct them.

Most people have probably heard of the term PCB. If you follow financial news, YouTube or read related articles, you might have come across this term. However, for those not in the electronics industry, the term PCBA might be less familiar, and sometimes it gets confused with PCB. Even though PCB and PCBA differ by just one letter, there is a significant difference between them in the electronics manufacturing industry.

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PCB/FPC/PTF, Soldering     WorkingBear    Views (1,473)     comment (0)