The newest IPC solder mask specification is the IPC-SM-840C. This spec breaks
the solder masks into two classes:\

   A. Class "T" - Similar to the Bellcore TSY-000078 specification

   B. Class "H" - Similar to the MIL-P-55110D military spec

Class "T" is similar to the old class 2 of the IPC-SM-840B spec which covered
masks for computer, telecommunications, instruments, etc type applications.
Class "H" is similar to the old class 3 wich covered masks for high
reliability and military type applications.

Hope this helps. For more info, please call me.

Larry Fisher
Dexter Electronic Materials
Phone: (317)-628-7401
[log in to unmask]

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