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Soldering flux trapped under the sensor's protective glass

Category: Hardware
Product Number: MAX86916

Hi team,

I am currently working on a board utilizing the MAX86916 integrated optical sensor. After the assembly and soldering process, I noticed that some soldering flux has somehow seeped into the sensor module and is now trapped underneath the protective glass, obscuring the optical area.

I am aware that the glass is sealed, and I have not attempted to pry it open as I know it might damage the delicate wire bonds and the internal optical barrier.

My questions are:

  1. Is there any recommended, non-destructive method to clean or extract flux from inside the sealed optical cavity of the MAX86916?

  2. Does this flux ingress permanently compromise the sensor's optical isolation and factory calibration, effectively rendering the module unusable?

  3. For future board assemblies, what are the strict assembly and soldering guidelines (e.g., specific no-clean flux, temperature profiles, or masking tape) to prevent flux from penetrating the glass seal of this specific component?

Any insights or recommendations would be highly appreciated. Thank you!