Design-for-test techniques utilized in an avionics computer MCM

Application Specific Electronic Module Program (ASEM), Final Technical Report.

“…This standard 'triplate' structure was evaluated for this MCM, but resulted in a cross section of 42 layers. By screening X and Y wiring channels on the same layer and stacking three wiring layers together before adding a reference plane, and by reducing [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] I I the wiring pitch from 0.020" to 0.010", the cross section was reduced to 20 layers. The screening technology required to achieve this is similar to what is used on redistribution layers, except the redistribution lines are generally much shorter.…”

“…For these samples, the 3 value at three standard deviations was at or below the minimum strength required by the military specifications. The C4 data (Table [4][5][6] shows that all values exceed the IBM specifications for the chip size and C4 count used. However, for the values denoted with the asterisk, significant levels of contact metallurgy failure at the chip were observed.…”

“…Design Ground Rules Document A "Design Ground Rules" [6] document is the description of all technology specific manufacturing requirements. (e.g.…”

“…The gallery cover plate closest to the MCM under test consists of a plate with tubular orifices which, when the door is closed, directs the nitrogen flow directly onto the chips requiring cooling. The readily replaceable cover plate is simple in I 1 [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] I i design, and inexpensive to fabricate, thus reducing the cost and TAT associated with thermal management during uncapped testing of MCMs.…”

Analyzing the design-for-test techniques in a multiple substrate MCM

“…A multiple-substrate MCM named the Standby Indicators MCM (SIMCM) was developed for avionics applications [7] using a variety of design-for-testability ideas for performing component, sub-circuit, and module level testing. The implemented DlT methods can be used for initial modulelevel production testing as well as real-time in-system background level testing.…”