What gives rise to the differences between C, I, M, and B products in a package? Are we using different materials for these?
C, I, M products:
These products use the same materials (die and packages) and processes. What distinguishes them is the testing temperature ranges that the various grades have to meet to satisfy the speed/timing conditions.
Products labelled as B-grade have undergone the "M" temperature testing, and the prescribed Military processing flows and screens. These flows (processing) subject B materials to special screening and inspections that the C, I, M products do not go through.