A discussion of a GaAs MCM fabricated at MicroModule Systems through the multichip module designers´ access service (MIDAS)

The MCM Designers´ Access Service (MIDAS) allows designers to obtain low cost, prototype and small quantities of MCMs. MIDAS low cost price structure comes from a multi-project environment where the customers share tooling and substrate manufacturing costs. The service acts as a technology enabler by supplying the designer with an interface “transparent” to the fabricator and common to multiple vendors. By completing front-end foundry tasks such as data preparation and mask fabrication and by grouping multiple users together on a run, MIDAS offers a low-cost prototype and small quantity service. Utilization of certain design guidelines module footprint size and I/O ring, layer stacking and number of layers and MIDAS supplied standard packages allow the user ample flexibility when designing a module and provides a comprehensive design environment. To date, MIDAS has accepted designs from commercial, military, and educational/research institutions. This paper presents an example of a module that pushes the current MCM-D technology to an extreme limit. The design was done at the University of Michigan and fabricated at MicroModule Systems in Cupertino, CA. It represents a joint design effort amongst the University of Michigan, Motorola, and Cascade Design Automation. It includes a selection of Mayo Foundation Standard Test Structures and six custom designed CGaAs chips fabricated by Motorola. This module is a technology evaluation vehicle that aims to characterize the MCM interconnect and driver-receiver pairs for signal integrity, and evaluate the design methodology in Motorola CGaAs (tm). A clock generator drives two pairs of serial-to-parallel and parallel-to-serial shift-registers at frequencies up to 1 GHz. One chip controls an unterminated databus which will be probed at one end. This MCM is the first of three MCM designs planned in the development of a 1 GHz clock processor which will execute a subset of the PowerPC (tm) instruction set selected to optimize performance in GaAs. This paper discusses MIDAS´ role in fabricating and assembling the module, the design effort among the parties listed above and the module´s functionality