SLVAFH0 December   2023 CSD13201W10 , CSD13302W , CSD13303W1015 , CSD13306W , CSD13380F3 , CSD13381F4 , CSD13383F4 , CSD13385F5 , CSD15380F3 , CSD17381F4 , CSD17382F4 , CSD17483F4 , CSD17484F4 , CSD17585F5 , CSD18541F5 , CSD22202W15 , CSD22204W , CSD22205L , CSD22206W , CSD23202W10 , CSD23203W , CSD23280F3 , CSD23285F5 , CSD23381F4 , CSD23382F4 , CSD25202W15 , CSD25211W1015 , CSD25213W10 , CSD25304W1015 , CSD25480F3 , CSD25481F4 , CSD25483F4 , CSD25484F4 , CSD25485F5 , CSD25501F3 , CSD75207W15 , CSD75208W1015 , CSD83325L , CSD85302L , CSD86311W1723 , CSD87501L

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Solving Assembly Issues with Chip Scale Power MOSFETs
  5. 2Land Grid Array (LGA) MOSFET Packaging Technology
  6. 3Wafer Level Chip Scale Packaging Technology
  7. 4Common Issues
  8. 5Best Practices
  9. 6Considerations When There are Problems
    1. 6.1 Tilted or Misaligned Packages
    2. 6.2 Solder Balls, Poor, or no Solder
    3. 6.3 Chipped or Cracked Devices
  10. 7Summary
  11. 8References

6.1 Tilted or Misaligned Packages

Tilting or misalignment of devices sometimes occurs during assembly. The following are some areas to look at when trying to resolve these issues.

  1. Check the printed solder paste from top and side view or read from solder paste inspection (SPI) data to make sure the solder volumes are consistent.
  2. Check the PCB land pattern design. Pads larger than recommended in the data sheet allow more space for the package to shift and rotate.
  3. It is critical that the package is picked up at its center. The package might shift inside the tape and reel pocket during transportation and might not be picked up accurately. Package placement needs to be adjusted using the package outline to the center of the PCB pads.
  4. Do not allow the package to free fall onto the PCB. Upon placement, the package needs to be level and in contact with the solder paste printed on the PCB pads. Placement force should not exceed 3N.
  5. Sometimes tilting can be due to handling, movement of the conveyor belt, or airflow from the fan inside the reflow oven.
  6. Visually inspect the package at a side view after placement and before reflow soldering. Inspect the package again post reflow. This can help isolate where the tilting occurs in the process.
  7. Review X-rays to see if there are any abnormal voids in the solder joint that can cause package to tilt.