LPS22HBTR and PCB cleaning

[DuncanR]

Dear ST/Forum,

We are using the LPS22HBTR pressure-temperature sensor in some PCB assemblies.

Due to some cleanliness requirements of the experiment, I need to be able to clean the PCB this device is attached to but due to the very fine holes in the lid to allow pressure to be measured, and your warnings in data to "not clean in solvent" etc, we are after some advice. I have purchased some liquid masking compound used in electronics assembly and propose to paint this onto the top of the device before cleaning and then peel it off after cleaning. Have you seen this done before and is it likely to cause a problem? I would prefer not to break a device trying this as replacing them on PCBs is difficult due to the geometry.

The masking compound is called Techspray WonderMASK P, Peelable Solder Mask Product# 2211. Data attached

Thanks in advance

Duncan

[Federica Bossi]

Hi @DuncanR ,

It is very difficult to know the type of masking compound material composition. The right way that our customers following is to use NO Clean solder paste for SMD parts and to clean only NO SMD portion of PCB.

[DuncanR]

Hi Federica,

Thank you for the reply and suggestion. Unfortunately I do not have the luxury of leaving any flux on the PCB. This is a high cleanliness vacuum application and the boards must be completely cleaned.

If there is no existing information on possible cleaning methods, I will have to experiment with the coating I have purchased. Theoretically it should work because it has no solvents or corrosives to affect the sensor, and the holes in the sensor are so small that this thick paste is unlikely to block them. I guess we shall see.

Regards

Duncan

[Federica Bossi]

Hi @DuncanR ,

Alright, let us know so it can be useful for other users :)

[DuncanR]

Sure. I will report back. 

Thanks

Duncan