Recently we get a series of EPCS4SI8N parts which are in flash memory type. After comparing with golden samples provides by our customer, we found several key differences in its die structure and surface marking pattern. We also find ST logo in golden sample's die marking surprisingly, although it is manufactured by Altera. Can any technical staff from ST explain these marking problems? Thank you! The following are the key differences of our products from golden samples:
Surface markings show big differences include that on Top and bottom patterns.
Our samples show no MFG logo but "MIAMI4M" and "2013-0329" die markings on die surface. Golden samples show ST's logo, copy right 2008 and "52JB 4" die markings on die surface.
All our samples don't match with golden samples both on surface and die markings. We hesitate that we buy fake parts. Please help to explain whether the markings can verify if these samples are good or fake. Thank you!