USR Alliance: Facilitating an Open Multi-Chip Module Ecosystem

In order to adapt to the ever-increasing bandwidth requirements, design complexity, the emergence of new processes and the integration of multidisciplinary technologies, the semiconductor industry is experiencing exponential growth and faster changes, all of which are getting shorter and shorter. The development cycle and the increasingly fierce competition have taken place. In other industry-driven areas such as software and hardware, similar challenges are being addressed through the establishment of a series of open alliances and open standards. This article does not want to list the names of all open federations here. The Open Compute Project, the Open Data Path, and the Linux Foundation are just some of the most prominent examples. But there is still a technology field that does not adopt this open collaboration. This is the Multi-Chip Module (MCM), which packages multiple semiconductor chips together to create a complete system in a single package.

The concept of MCM has been around for a while in the industry, with a variety of technical and market advantages, including:

Higher yields—By splitting silicon into multiple wafers instead of building large single chips with low yields, high cost (and sometimes even no manufacturing), you can significantly increase the yield of each component and even the overall solution. Higher yields eventually translate into lower costs.

Optimized Process - The final MCM product is made up of mix-and-match units with different manufacturing processes, so process optimization can be performed for specific IP modules with similar characteristics.

Multiple manufacturing plants - can create specific products with different production lines with unique features.

Product Category - Easily create new products by combining different quantities and types of devices to create innovative and cost-optimized MCMs.

Shorten product development cycles - each wafer can be upgraded independently, which makes it easy to enhance the functionality of new products and/or the ability to correct problems within a specific wafer. For example, new products can be integrated with new I/O interfaces without the need to redesign and change the parts of the solution that are stable, avoiding wasted time and money.

Economies of scale - Each wafer can be reused in a variety of applications and products, increasing the volume and yield of mass production, thereby increasing the overall return on product development investment.

Subdividing larger semiconductor devices into smaller wafers and mounting them on MCMs has become a new trend in printed circuit boards (PCBs) with smaller footprints and lower power. Consumed, higher performance and more extended features.

Now, we can imagine that the advantages listed above are not limited to a chip supplier, but can be shared by the entire industry. By opening and normalizing the interface between the chips, it is possible to introduce a truly open platform under which companies from different companies with their own technical expertise can create a company beyond any single player. And a variety of new products.

This is where the USR Alliance advocates implementation. The USR Alliance has defined ultra-short-range (USR) links optimized for very short-range communication between components contained in a single package. Existing ultra-short-range (VSR) PHYs that span package boundaries and connectors need to face some technical challenges that are not part of the package, while USR links can provide higher bandwidth, lower power consumption and smaller Chip size. In addition, the USR PHY is based on multi-line differential signaling technology and is optimized for the MCM environment.

There are many applications that can be implemented over USR links such as CPUs, switches and routers, FPGAs, DSPs, analog components, and various long-range electro-optical interfaces.

Figure 1: A possible example of MCM wiring

As an active promoter of the USR Alliance, Marvell is working to build an ecosystem of interoperable components, interconnects, protocols and software to help the semiconductor industry bring more value to the market. The USR Alliance is working with industry and other standards development organizations to create PHY, MAC and software standards and interoperability protocols, while also promoting the development of a complete ecosystem of USR applications, including certification programs, to ensure broad interoperability. system.