Quick Reference – Die Removal




  • Tacky Flux
  • Lint Free Wipes
  • Isopropyl Alcohol
  • Solder Braid (wick)
  • Flux Cleaning Pen
  • Solder Mask Repair Pen
Die attachment equipment and supplies


  • Anti-Static Mat
  • ESD Wrist Strap and ESD coat
  • PCB Heat Plate
  • Hot Air Gun
  • Soldering Station
  • Microscope
  • Anti-Static Tweezers
  • Exacto Knife or Scalpel

Handling Die Precautions

  • ESD precautions are REQUIRED.
  • Prevent overheating the work piece and die.
  • Use a hot air gun nozzle with diameter slightly larger than the largest die dimension.
  • Warning Warning: excessive airflow will move the die.
  • Soldering temperatures are critical and deviations in excess of ±10ºC can cause problems.

Anti-Static Measures

Anti-Static Measures Static warning
  • Rework must be done on an anti-static mat or bench that is connected to earth.
  • Connect all test equipment to ground.
  • ESD wrist strap and ESD lab coat MUST be worn.

Check for Under Fill

  • If die is encased in under fill, load the board onto a holding device such as a vice.
  • Focus on the die location under a microscope.
Under Fill

Under Fill Removal (skip if no underfill present)

Remove Under Fill
  • Remove the underfill from around the die using a SHARP scalpel.
  • Minimize damage to the die and PCB.
  • Clean area around the die using isopropyl alcohol and lint free wipes and allow to dry.

Prepare PCB for Heating

Prepare PCB for heating
  • Place the board on the heat plate fixture.
  • Attach the thermal sensor of the heat plate to the PCB.
  • Insert the hot air gun into the hot plate gun holder.
  • Center the nozzle of the hot air gun over the die to be removed.
  • Raise the hot air gun to its highest position.

Die Removal

Heating precaution
  • Pre-heat work-piece to 150ºC.
  • Set hot air gun to 150°C with near minimum airflow to prevent the die from blowing away.
  • Lower the hot air gun to approximately 1/16” (1.5mm) above the top of the die and set the temperature to 200°C for 45 seconds.
  • Raise the gun temperature to 240°C for 30 seconds.
  • Increase the gun temperature to 260°C.
  • Once at 260ºC for at least 12 seconds and no longer than 15 seconds, carefully pull die off the board with stainless steel tweezers.
  • Avoid excessive force. If experiencing difficulties removing the die, then:
Die Removal Procedure
  • Increase temperature of the hot air gun by 10ºC (Never exceed 280ºC OR 25 seconds).
  • Turn-off hot air gun, allow to cool, and check for under-fill.

Cool Down and Clean Up

Static warning
  • Once die has been removed, turn off hot air gun but not the heat plate – eases solder removal on pads with lots of copper.
  • Place hot air gun into holder, not onto the heat plate.
  • Using a soldering iron and wick, remove excess solder pad from the pads by stroking the braid in a lengthwise direction to reduce risk of damaging pads.
  • Inspect work under a microscope.
  • Turn off heat plate and allow PCB to cool.
  • Clean die pad area with flux cleaner pen, wipes and/or isopropyl alcohol. Remove any residual under-fill and wipe clean.
Clean Up and Cool Down

Inspect Board for Damage

Inspect for Damage Static warning
  • Inspect the pad area to determine if PCB can be re-used/ repaired
  • Use the evaluation criteria (#10 and #11 below) during the inspection to determine if board can be re-used
  • Fix damaged solder mask areas using a Solder Mask Repair Overcoat Pen (Circuit Works CW3300G) – EPC dies are solder mask defined. If repairs are made, make sure all repairs are cured and dried prior to proceeding with die attach.

Board Rework Evaluation Criteria: Acceptable

Acceptable Damage (Board can be reworked):

  • Minor breaks in solder mask around die.
  • Negligible damage to copper where die was attached.
  • Any silk screen damage.
  • Any copper damage well outside the die area.
Board Evaluation

Board Rework Evaluation Criteria: Unacceptable

Unacceptable Damage (Board will need to be scrapped):

  • Any visible copper pad/trace damage (bending, scoring, buckling, breakage) in the area of the die.
  • Any blistering of the PCB – can break internal vias.
  • Any scorching of the PCB – can cause voltage breakdown.
  • Any excessive mask damage – die is mask defined and needs the mask for proper alignment.
Board Evaluation Unacceptable  

ANY ONE of these conditions present, then scrap the board

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