Honeywell AWM2100V mass airflow sensor (http://sensing.honeywell.com/product%20page?pr_id=25698)
Guessing the 9503 is a date code so tagging it as such.
Blog posts:
Package
Board
Ceramic, looks like Al2O3. Two layers of metalization plus thick-film resistors. Blue dielectric may be glass or polymer, not sure which yet.
Die
One layer of polysilicon resistor plus one layer of gold metalization.
Die is <100> oriented as can be seen by the KOH (or similar) etch used to define the cavity under the membrane.
