How to Clean Black Pasted IC Safely and Properly

In mobile phone repair, a major challenge is handling black pasted ICs. They often seal them with this strong black glue or compound to keep them from damage or tampering. If someone needs to carry out a repair or replacement, they must remove the glue with care. Improper cleaning might lead to damaging the board or the IC itself.

In this blog, you'll learn how to remove black adhesive from a PCB step by step. We'll also cover cleaning the area and preparing the IC for reballing. We will also discuss the best tools for the job, safety tips, and common errors to avoid.

What Is a Black Pasted IC?

A black-pasted IC is an integrated circuit covered in black glue or compound. Mobile manufacturers often use this glue to block moisture. It also helps prevent tampering and protects the chip from damage. If you want to repair the chip, especially if you want to remove it, this black compound becomes an issue.

Why Cleaning Black Pasted IC Is Important

Here are the reasons why cleaning a black-pasted IC is important:

• You need to replace or repair the chip.
• Preparing the IC for reballing.
• Working on logic board repairs in mobile devices.
• When black glue is blocking a few connections on the board,
• If someone does not clean it well, the IC could get damaged, or they might lose key connections on the PCB.

Tools for Cleaning Pasted IC

The tools employed should be apt for cleaning the paste off black ICs. Otherwise, the chip or motherboard gets damaged. Common tools include:

• Technicians use a hot-air rework station. They heat the black compound to soften it while applying heat.
• Use a plastic or wooden spudger to scrape the glue off with care.
• The technician uses tweezers and a needle to pick off the glue in detail.
• Flux and solder wick are used for cleaning the solder pads.
• Isopropyl alcohol (IPA 99%) is useful for the final wash.
• BGA Cleaner or Paste Remover is helpful as a solvent for hard glue.
• A microscope or magnifying glass helps you see and examine small IC pins with clarity.
• ESD mats and wrist straps protect components from static charges.

How to Remove Black Paste IC in a Safe and Proper Manner

Cleaning a black pasted IC takes patience and care. Do it right, or you might damage the board or components. Here are some of the things you need to consider to arrive at a safe and proper cleaning:

Start by softening the black glue.

This step aims to soften the black compound. This helps in removing it in a manner that protects the IC and the board from damage. This step loosens the adhesive. This makes cleaning easier and safer.

• Use a Hot Air Rework Station: Set the temperature to about 280°C to 320°C, based on your board type. Keep the airflow low to avoid blowing away nearby components.
• Watch for Softening Signs: The glue will begin to change color and will become sticky or soft. This is the best time to remove it.
• Avoid Overheating the Area: Too much heat will ruin the PCB and lift away the solder pads.

Use Safe Tools to Remove the Compound

Sometimes, the heat makes the black glue soft, and we need to remove it. This is necessary to ensure it works well with the IC and the PCB.

• Choose a Plastic Spudger or Wooden Stick: These tools are gentle, making it safer to remove the black glue.
• Avoid Using Metal Tools in the Beginning: Metal tools could very well damage IC pins or lift solder pads. Use them for final cleaning only, if at all.
• Work with care and take your time; don't rush the process. Thin layers are all you should aim for as you scrape the glue off to ensure the protection of the board.
• Use flat and angled tools for different areas: Flat tools work well for wide spaces. Use angled or pointed tools for tight corners.
• Hold the PCB steady while cleaning: Place the board on the ESD mat or holder. This keeps it secure as you remove the compound.

Clean Hard-to-Reach Areas Carefully

After the top layer removal of black glue, some sticky bits may remain near the pins or below the IC. You must remove such bits with great care not to damage small components.

• Use fine-point tweezers or a needle: They help lift glue from small spaces around IC pins and corners.
• Look under a microscope or magnifier: This close-up view helps you see where the glue is stuck. You can then remove it safely without harming the board.
• Scrape Gently, Not Forcefully: Apply light pressure always. Excessive pressure can lift pads or break fine connections.

Apply a chemical cleaner if needed

Most of the time, the black glue is difficult to get off using heat and pulling with the tool. In such situations, going for a safe chemical cleaner that dissolves the glue would do no harm to the PCB.

• Pick the Right Cleaner: Use BGA Glue Remover or 99% isopropyl alcohol. Both are safe for electronics and dissolve tough black glue.
• Apply with a brush or dropper to the glued area with a light touch. Do not be overly generous with the chemical; a thin layer to cover all the sticky bits will suffice.
• Let It Sit for a few minutes: You have to wait for 5 to 10 minutes for the chemical to soften the glue.
• Avoid Harsh Solvents: Don’t use strong chemicals, as they can damage the PCB layers or leave stains.

Wipe and Dry the Area After Cleaning

After removing the black glue and residue, it prevents the formation of short circuits and prepares the board for the next repair step.

• Final Cleaning with Isopropyl Alcohol (99%): Use a clean cotton swab or cloth soaked in alcohol. Gently wipe the IC area. This will help remove dirt, flux, and chemical traces.
• Inspect under a light or microscope: Check for staining, residues, or any looseness. Ensure that you leave nothing behind.

Prepare for the Next Repair Step

After you fully clean and dry the IC and the board, you advance. Proper cleaning provides solid bonds and a successful repair.

• Check for Damaged or Missing Pads: Repair any lifted or missing pads before installing the new chip.
• Clean the pads with flux and solder wick: First, apply some flux. Then, heat the solder with the iron. Finally, use the wick to remove the old solder from the pads. It should create a flat and shiny surface for soldering.
• Make sure the area is flat and smooth: A smooth surface is key for reballing or placing the new IC. If there is unevenness, one has to give it yet another cleaning.
• Using a Microscope for Final Inspection: Check cleanliness under the microscope and look at the alignment of all edges and corners.
• Get the Right IC Ready for Soldering: When the board is ready, place the correct IC on it. Then, follow the usual reballing or soldering steps.

Conclusion

Anyone in mobile repair must carefully remove the black paste from an IC. They need to do this safely and without making a mess. Use the right mobile repair IC cleaning tools to soften and remove the black compound from the board. Use these tips to clean black compound ICs safely: gentle heating and safe tools. This helps keep the board undamaged.
After cleaning the black glue from the PCB, we will join the IC. This can include IC reballing or replacement. When removing glue or SMD ICs with black glue, take your time.
Be patient and precise to keep the board safe and working like new.

Frequently Asked Questions

Q1: Can an IC with black paste be cleaned without heat?

Not very easily. Heating softens the glue and makes its removal safer.

Q2: Is alcohol enough to remove all the glue?

It works well for light glue but may require help from a BGA cleaner.

Q3: What happens if you use metal tools too early?

You may damage the solder pads or the PCB traces.

Q4: What tools should you choose for cleaning the post-paste IC?

Some essential ones would be a hot air station, a plastic spudger, tweezers, flux, and isopropyl alcohol.