How did you determine that? I looked at the datasheet for the stm8s003 and wasn't able to correlate the markings to a part number.The first one seems to match stm8s003 microcontroller.
Ok, I see it now, thank you very much!I googled "phf6 qfn", got a picture of very similar chip but S103. Then googled stm8s003 datasheet, and on page 96/103 is UFQFPN20 package with marking S033 in the top row.
If you google S033 qfn you will get even better result for pictures.