Metrics: Reliability

Available Reports

PPM/FITS Summary: A graphical trend of National Semiconductor's Reliability Performance.

PPM/FITS - By Process: Failure Rates of Major Processes at National Semiconductor.

Package Data: Failure Rates of all Packages at National Semiconductor.

In reviewing this data, it may be helpful to refer to our Process by NSID Cross Reference Table (pdf: 1.8MB) and information on our Reliability Testing Programs.

Purpose of this Metric

• To provide a periodic monitor of product reliability under accelerated test conditions on wafer fabrication and assembly processes.
• To provide fab process and package reliability performance characteristics to customer.

Audit Strategy

• Package/Assembly processes are audited by Autoclave (ACLV), Temperature and Humidity Bias Test (THBT) and Temperature Cycling (TMCL) tests.
• Wafer fabrication processes are monitored by EFR and Long Term High Temperature Operating Life (OPL) tests.
• Devices are selected within each package and process audit groups based on representability and high manufacturing volume. Each audit group contains at least 3 devices.

Test Frequency

PPM/FITS Summary 

National Semiconductor conducts a Long Term Audit (LTA) program in order to identify trends in reliability of our products. The chart below displays the Early Failure Rate (PPM) and Long Term Life Failure Rate (FITS) trends for these products.

The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

The trend lines for both PPM and FIT rates illustrate the positive year to year reliability improvements at National Semiconductor.

PPM/FITS by Process 

The following table lists Early Failure Rates in parts per million (PPM ) and Long Term Failure Rates in units per billion device hours (FITS) for the wafer fabrication processes.

The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

The data used to calculate the failure rates was obtained from OPL tests performed in the Reliability Monitoring Program; and from Reliability Qualification where applicable

These failure rates are updated quarterly with data through the end of the preceding quarter.

Note: PPM is a point estimate based on rejects and sample size for EFR.
* - Data from previous time range 02/24/2003 - 02/27/2004

Package Data - Reliability Monitor Plan 

The following tables list failure rate in percentage (PCT) for packages. The data used to calculate the failure percentage was obtained from ACLV, THBT and TMCL tests.

These tables are updated quarterly with data through the end of the preceding quarter.

Percentage = Rejects/Sample size * 100
Period Covered: 29th Feb 2004 to Feb 2011
Last Updated: 3 October 2011