• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 34 subscribers
  • Views 121 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ESD441: Regarding Component Tilting During Reflow

Kyohei
Expert 2551 points

Part Number: ESD441

Hi team,

When the customer mounted the ESD441DPLR and ESD341DPLR on the PCB using a reflow process, component tilting was observed.
According to the datasheet, the implementation was performed using a metal mask thickness of 100 µm, a metal mask aperture size of 0.28 × 0.25 mm, and the recommended land pattern.
If there are any inaccuracies or issues with the above information, please kindly advise.
Best regards,
Kyohei
  • 0
    TI__Genius 12310 points

    Hi Kyohei-san, 

    This should be okay. I am confirming with our packaging team on this and will get back to you when I have an answer. 

    Best,

    McKenzie

  • 0 in reply to McKenzie Eaker
    Expert 2551 points

    Hi McKenzie-san,

    Thank you for your support.

    Regarding the above matter, could you please advise on the current status of your investigation?
    In addition, we have performed further confirmation with the customer and have some additional questions for your review.

    --------------------------------------------------------------------

    We have also confirmed the reflow conditions.
    Prior to assembly, temperature profile measurements were conducted, and we verified that the entire PCB was heated uniformly, that the conditions were within TI’s recommended temperature range, and that no excessive peak temperatures were reached.
    For the PCB in question as well, none of these issues were observed.

    Furthermore, reflow soldering was performed under a nitrogen (N₂) atmosphere, with an oxygen concentration of 3000 ppm or less.
    The solder paste used was a standard Sn96.5–Ag3.0–Cu0.5 alloy, with a melting temperature of 217–220 °C and a viscosity of 200 Pa·s.

    It should be noted that the tilt observed in this case is not along the short-axis direction of the component, but rather a rotational tilt along the long-axis direction, and it occurred on nearly all units.
    For this reason, we believe that the phenomenon cannot be sufficiently explained solely by a simple imbalance in solder volume between the left and right pads.

    In this context, we would appreciate your confirmation on the following points:

    • Are there any reported cases in which this package tilts in the long-axis direction during reflow?
    • When this package is assembled on a PCB together with large components such as CPUs, are there any package-specific assembly precautions or considerations that should be taken into account?

    While we believe that general assembly conditions have been properly observed, we would appreciate it if you could share, to the extent possible, any package-specific structural characteristics or design considerations that should be taken into account.

    ---------------------------------------------------------------

    Best regards,

    Kyohei

  • 0 in reply to Kyohei
    TI__Genius 12310 points

    Hi Kyohei-san, 

    Another customer brought this question up as well and we are working with our packaging and manufacturing team to get information on correctly soldered units and not correctly soldered units. As well as getting an understanding on how much tilt is okay for the device to continue functioning. 

    I will get back to you in the next few days with more detailed information. 

    Best,

    McKenzie

  • 0 in reply to McKenzie Eaker
    Expert 2551 points

    Hi McKenzie-san,

    Thank you for your support. I look forward to working with you.
    Best regards,
    Kyohei
  • 0 in reply to Kyohei
    TI__Genius 12310 points

    Hi Kyohei-san, 

    I heard back. Tilting is common across the long-axis for this package due to the size. To manage tilting, it is best to follow the stencil design and control the amount of solder paste. Too much solder paste can lead to higher amounts of tilting. 

    There are some packages that have a side wall, called Wettable Flank packages and these can help reduce tilt due to the solder going up the side of the package. We currently do not have devices with this, but we are working on it. 

    Best,

    McKenzie