Choosing a Semiconductor Process

In order to maximize your return-on-investment for an IC development, the choice of fab process and fab partner are critical. The breadth of process costs and technologies has never been larger. This guide will outline the steps needed to make this critical decision for your product.

Review Your Requirements

  • Prototype ready date, unit cost target, development cost budget
  • Product lifetime, sales volume, ramp
  • Performance requirements: speed/bandwidth, power, physical size, noise, supply voltages
  • Content: Number of logic gates, major functional blocks defined, implementation details estimated
  • Identify needed functional blocks that may be available to buy as existing IP (intellectual property)

Process Options

Collect information for process candidates that meet the business and technical requirements:

  • Wafer size, cost, and minimum lot size
  • Schedule from tape-in to finish of prototypes and production wafers
  • Minimum annual sales needed to meet the fab partner’s requirements
  • Availability of IP and tools support to meet your development team’s requirements
  • Mask set cost, multi-project wafer cost, and schedules

Making the choice

  • Comparing process options
  • Calculate NRE (non-recurring engineering) costs for each viable process option: IP costs, development engineering, software, wafers, masks, production lot qualification. Assume a re-spin for both schedule and costs.
  • Estimate die size for each process option
  • Calculate GDW (good die per wafer) for each process option.
  • Calculate production unit costs for each viable process option: wafer$/GDW + unit test + unit package
  • Compare NRE$, unit costs, and schedule