Multi Chip Packages (MCPs)

Multi-chip module packages, or “system in a package,” in combination with BGA technology, are viewed as part of the solution set for the widening gap between silicon I/O density and performance and the material capabilities of the package and board/substrate.

Multi-chip module packages can be viewed as standard single-chip modified to accommodate the multiple ICs and passive components to provide the user with much higher functionality integration. Most MCP’s typically incorporate 2 to 6 stacked die and are packaged in conventional BGA, LGA, CGA, QFP, PGA, or PLCC.

Some of the advantages of multi-chip module packaging include:

• Ability to achieve greater functionality in a time-to-market window that cannot be met through silicon integration. Increased density and performance and reduced size and weight at the board or system level
• Reduced board area and routing complexity at the next level. Often, board layer reduction offsets the additional costs of using multi-chip packages
• Design optimization through use of the most cost-effective silicon solutions and assembling different semiconductor technologies, die geometries, or chips from different fabs in the same package
• Value added of high-speed designs, assembly processes and material set incorporated into the MCP
• The ability to incorporate stacked die or multi-level two sided packages increase density even further
• Incorporation of different interconnection technologies, either flip-chip and wire bond, into the MCP are easily accommodated
• Allows the OEM to upgrade products by using die-shrinks in the same package
  

WEDC’s Role in the MCP Market

WEDC serves the data-communication, high-end computer and military-aerospace markets with standard and custom multi-chip package solutions.

As a merchant MCP supplier, WEDC began designing and building MCPs in 1987 and has been on the forefront of the technology ever since. Continued advances in high performance system requirements have created the need for increased integration of high-density electronics. Ruggedized subsystems offering reduced size, lower weight and improved electrical performance is the core of WEDC MCP technology.

Today WEDC has full designs, fabrication and test capabilities for a wide selection of multi-chip module devices. The WEDC product offering includes standard off the shelf memory MCPs and select processor MCPs for demanding applications. Memory MCPs include SRAM, SDRAM, flash and EEPROM technologies and combinations of these. Custom MCP designs based on customer supplied silicon takes advantage of these capabilities as well.

Packages and Materials

Packaging options include standard PBGA, CBGA, fully hermetic ceramic QFP and PGA as well as standard monolithic SOJ, flat pack and DIP.

WEDC uses a variety of interposer materials including alumina ceramic, high-TCE ceramic, laminate and resin technology. These materials are used with chip-on-boards, wire bond and flip chip assembly capability.

Plastic encapsulations for PBGA devices are capable of passing JEDEC standard moisture qualification testing, temp cycling, and HAST.

Engineering and Design

WEDC’s engineering team is fluent in all aspects of MCP device design and system performance requirements, including:

• Expertise in package construction requirements with regard to size and weight and associated thermal, mechanical and power considerations
• Expertise in environmental requirements from commercial testing to full military qualification
• Expertise in writing and implementing test software for complex memory and microprocessor circuits
• Expertise in system requirements, including memory, processor, coprocessor, cache memory, oscillators, timers, graphics options, interrupts, on-board clocks, and other logic functions
• Utilization of leading edge developments software for thermal, mechanical and electrical performance and emulation of the package
• Utilization of design tools that integrate system-level modeling and simulation and data transfer between chip, package and board design environments
• BLR analysis and qualification of MCPs for extended temperature applications