October 8, 1998

Change partners and dance

Jim Lipman, Technical Editor

Silicon-foundry and ASIC-vendor roles for chip design and fabrication are changing. If someone had asked me 10 years ago what a silicon foundry does, I would have said that the foundry processes silicon wafers for chip vendors that either have no silicon-processing capabilities or have an undercapacity problem at their own processing facilities. However, today's silicon foundries are taking on more of the tasks that ASIC companies traditionally handled.

In the mid-1980s, ASIC vendors offered a range of products and services for their customers, resulting in one-stop shopping for many companies. Designers went to ASIC companies for their expertise in designing leading-edge chips. ASIC customers often accessed this expertise through the services of geographically distributed design or technology centers in strategic places throughout the country or, in some cases, throughout the world. Besides having knowledge of high-complexity design methodologies, ASIC designers also had experience using the EDA tools needed to design high-density, high-speed chips.

Design tools came from ASIC and EDA-tool vendors, which counted ASIC companies among their best customers. ASIC and EDA vendors often worked closely to verify new EDA tools before the EDA vendor made these tools available to other customers. Along with some internally developed tools, the ASIC houses supplied cell libraries, covering both standard-cell and gate-array design implementations. Supplementing ASIC cell libraries were compilers for structured blocks, such as SRAMs, ROMs, and even datapaths. In addition, many ASIC companies also developed megacells, which were larger, more complex blocks of predefined and preverified logic that you could use on multiple designs. Megacells were the forerunner of today's intellectual-property (IP) cores. Rounding out this rather full set of offerings was state-of-the-art wafer processing at the ASIC vendor's facilities, followed by chip packaging and testing. Silicon foundries were just starting out and offered one product—silicon-wafer processing.

Fast-forward to the present, when the roles of ASIC vendors and silicon foundries have changed a lot. Third-party EDA tool and library vendors have eliminated design-tool and cell-library products from most ASIC companies. Foundries have forged partnerships with many EDA-tool, design-library, and IP vendors. These relationships allow such vendors to design their products for and verify their products on a process-by-process basis, a necessary consideration with deep-submicron complexity. Foundries have also become the place to go for some ASIC libraries and memory blocks (including DRAM and flash). Finally, a process-technology gap between ASIC companies and foundries is shrinking along with the process technology. One major foundry claims that by 1999, its most advanced process will be on par with that of a leading microprocessor company. So, what's left for the ASIC vendors? Plenty.

ASIC companies still offer important products and services for chip designers. ASIC vendors have a good understanding of deep-submicron-design methodology, because the vendors use this methodology for their own ASIC and standard-product chips. For both hard and soft IP cores, third-party vendors are excellent sources for common blocks, such as Universal Serial Bus and PCI cores, but the more complex nature and customer-specific attributes of DSP, microprocessor, and true ASIC cores mean you're probably better off getting these cores from an ASIC vendor.

As a designer, this change of vendor sources means that you win. You get your design tools, libraries, cores, and design methodology from companies specializing in these products and services. ASIC companies know how to design complex chips and have the high-end cores needed for these chips. Foundries have become good sources of well-verified silicon processing and have added ties to core and library vendors to make their products more robust. You're changing partners, but the dancing doesn't stop. In fact, the music is getting faster.

You can reach Technical Editor Jim Lipman at fax 1-925-606-1563, or ednlipman@mcimail.com.

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