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TMP006: Question about soldering of the component.

Derry Malmberg
Prodigy 20 points
Part Number: TMP006
Other Parts Discussed in Thread: TMP007

We have designed a product utilizing the tmp006 IR-sensor from TI.
We are ready to ramp up production within 2weeks to 2k units per batch when we found some problems with the sensor 

we noticed that the production have placed solder paste on the copper area below the IR-sensor.
But the copper area under the sensor shouldn't have any solder paste, only the solder balls, right?
According to the PDF on TI's homepage, SBOU 143B, on page 25 it clearly states that  "Copper square in the center is a MUST too" 
But this area should be kept clean, only copper and gold plating? 

We've had some problems with our pre-series production and I am afraid that it is because the soldering paste might have touched the die or even damaged it...

Thanks for your time!

  • 0
    TI__Expert 5695 points
    TI support team will contact you shortly.
  • 0
    TI__Mastermind 35895 points
    Hi Derry,

    The TMP006 and TMP007 Layout and Assembly Guide that you referenced is indicating that the copper square is a necessary feature of the layout. It aids in temperature stability of the sensor. However, this square is not a pad or electrical connection. In fact, it's critical that this feature not contact the device. It's possible to damage the thermopile by contacting the device in this location. Therefore, you should not apply solder paste to this square, and you should take special care when handling and cleaning this area of the device.

    Thanks,
    Ren
  • 0 in reply to Ren Schackmann
    Prodigy 20 points

    Hello Ren,
    Thanks for your answer, I have some additional questions.
    Are we allowed to put solder mask on the copper area under the sensor?
    If we don't place any solder mask, what type of plating is allowed on the copper and what type is preferable?

    Many thanks for your time!

    Best regards
    Derry 

  • 0 in reply to Derry Malmberg
    TI__Mastermind 35895 points
    Polished metals have the lowest emissivity, so they will contribute the least amount of undesirable (offset) radiation. We have chosen to build our EVM with gold plating (ENIG.) I would caution against very cheap finishes (such as HASL) which will leave the surface non-planar. We have built PCBs with solder mask over the square, and they work as well.

    Ren