Nondestructive and destructive evaluation of selected package assembly schemes (2 and 3 for CuMoCu and 6 and 8 for CuW) using each [Al.sub.2][O.sub.3] variety showed insulator frame cracking (postfabrication) for CuMoGu/96 percent ZTA structures, as shown in Figure 7, and base-flange/bond interface voiding, as shown in Figure 8.
The 96 percent 99 percent and ZTA materials possessed sufficient strength to be considered in the application with CuW structures for all thickness and process variations.
For a given thickness and assembly brazing/process temperature, a base-flange material change from GuMoCu to CuW produced a lOx decrease in warp deformation, 10 to 15 x decrease in stress in the [Al.sub.2][O.sub.3] critical corner region and 7 to 10 order of magnitude decrease in the [P.sub.f] of the [Al.sub.2][O.sub.3].
Several CuW flanges fabricated for use with RF power devices and circuits are shown in Figure 2.
Figure 3 shows CuW carriers for use in advanced microwave applications.
When fabricated with the new CuW composite materials, all of these products benefit from the materials' enhanced properties.