SAN JOSE, USA: The Global Semiconductor Alliance (GSA) has released its Analog/Mixed-Signal/Radio Frequency (AMS/RF) Process Control Monitoring (PCM) Checklist Version 1.0. The tool was developed by the GSA AMS/RF Working Group’s PCM/Process Checklist Sub-Working Group.
Process control monitors collect parameter data when testing specific structures placed on a semiconductor wafer. The parameter data collected is used to set accept/reject standards for each wafer. Yield, or good die per wafer, should be tightly correlated with parameter measurements that center on an average value.
Today, documents describing parameter measurements vary with each foundry, as foundries have different approaches to deciding what to measure, how to make the measurement and how to report the data. And the data presented is geared towards wafer acceptance standards, as opposed to being a tool that design engineers can use to design better yielding chips.
GSA’s AMS/RF PCM/Process Checklist Sub-Working has developed a checklist that provides:
(1) a recommended list of parameters that foundries should measure (i.e., test),
(2) a uniform way to measure each parameter (i.e., describe the measurement), and
(3) a consistent way to describe the test data.
The checklist includes the following information:
* Device (e.g., FET)
* Parameter (e.g., Drain-Source Breakdown)
* Parameter Measurement Definition
* Parameter Class (e.g., Reliability)
* Units (e.g., Volts)
* Layer (s)
* Type (e.g., N/P)
* Category (e.g., Pass/Fail)
* Structure Information.
Fabless and fab-lite companies, which are the targeted users of the Checklist, benefit from using the tool as it helps them better understand and use the parameter data they receive from their foundry partners. Better understanding yield and how it is affected by various PCM parameters allows fabless companies to design higher yielding chips.
“Previously, PCM data was not always easy to understand,” stated David Schwan, senior staff CAD engineer at Volterra and chairman of GSA’s PCM/Process Checklist Sub-Working Group. “By presenting a consistent format for recommended measurements and language describing the measured data, the Working Group hopes this will open up PCM data to a wider audience, expanding from foundry and product engineers to include design engineers and managers.”
Wafer foundries, which are classified as the Checklist providers, benefit because the quality of communication with semiconductor companies is greatly enhanced and improved; therefore, it becomes an effective marketing tool to acquire new, as well as maintain existing customers.