Information Notice 2002-32, Electromigration on Semiconductor Integrated Circuits
| ML023080088 | |
| Person / Time | |
|---|---|
| Issue date: | 10/31/2002 |
| From: | Beckner W NRC/NRR/DRIP/RORP |
| To: | |
| Foster J, NRR/RORP, 415-3647 | |
| References | |
| TAC M5261 IN-02-032 | |
| Download: ML023080088 (6) | |
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555-0001 October 31, 2002 NRC INFORMATION NOTICE 2002-32: ELECTROMIGRATION ON SEMICONDUCTOR
INTEGRATED CIRCUITS
Addressees
All holders of operating licenses for nuclear power reactors except those who have ceased
operations and have certified that fuel has been permanently removed from the reactor vessel.
Purpose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to inform
addressees of a failure mechanism identified in semiconductor components at the Kashiwazaki- Kariwa Nuclear Power Station Unit 5 of the Tokyo Electric Power Company, Inc. (TEPCO). The
failure mechanism has been attributed to electromigration. It is expected that recipients will
review the information for applicability to their facilities and consider actions, as appropriate.
Suggestions contained in this information notice are not NRC requirements; therefore, no
specific action or written response is required.
Description of Circumstances
In July and September of 2001, control rods at the Kashiwazaki-Kariwa Nuclear Power Station
were temporarily rendered inoperable due to defective control rod transponder cards. The
Nuclear and Industrial Safety Agency (NISA) of Japan identified the failure mechanism as
integrated circuit (IC) wire breakage and attributed it to electromigration in aluminum (Al) wires
with small crystal grains. The root cause has been determined to be inadequate quality control
methods in the IC manufacturing process. All of the ICs that failed were traced to the HITACHI
Takasaki Works and were manufactured in September of 1986. Further investigation revealed
that between 1985 and 1990, ICs in which Al vapor was deposited by electron beam had small
Al crystal grains.
TEPCO implemented an action plan to evaluate other systems and replace transponder cards
where a single defect in an IC could affect plant safety functions or plant control. Other
businesses operating nuclear reactors where the same phenomenon has occurred have been
advised to develop appropriate management and maintenance plans and to report defects.
Discussion
Electromigrationthe drift of metal atomsis an age-related phenomenon that has been
confirmed to occur in Al wires and traces. It appears to correlate with high current densities in
traces or wires with small cross-sectional areas. The movement of the atoms creates voids that
may eventually present themselves as electrical interconnect failures. Recent research has
shown that this failure mode is strongly affected by the grain structure size of the Al trace or
wire, and can be delayed or overcome by metallurgical modifications to the microstructure.
Other methods for reducing the effects of electromigration include limiting the current density
and minimizing flaws during the deposition process.
While electromigration has the potential to adversely affect all ICs that have Al wires with small
cross-sectional areas and operate at high current densities, the interconnect failure mechanism
would not be expected to occur simultaneously in redundant safety-related components. It is
also expected that failures in safety-related circuits due to manufacturing defects or operational
conditions would likely be detected by routine surveillance, testing, or diagnostics and that the
followup root cause analyses and corrective actions would address the generic aspects of the
failure.
It is expected that 10 CFR Part 21, Reporting of Defects and Noncompliance, would be the
method used by licensees to notify the NRC of component failures. Therefore, IC failures due
to electromigration would be reportable under 10 CFR Part 21 for safety-related instrumentation
and control components.
This information notice requires no specific action or written response. If you have any
questions about the information in this notice, please contact the technical contact listed below
or the appropriate Office of Nuclear Reactor Regulation project manager.
/RA/
William D. Beckner, Program Director
Operating Reactor Improvements Program
Division of Regulatory Improvement Programs
Office of Nuclear Reactor Regulation
Technical contact: C. Graham, NRR
(301) 415-3201 E-mail: cxg2@nrc.gov
Attachment: List of Recently Issued NRC Information Notices Discussion
Electromigrationthe drift of metal atomsis an age-related phenomenon that has been
confirmed to occur in Al wires and traces. It appears to correlate with high current densities in
traces or wires with small cross-sectional areas. The movement of the atoms creates voids that
may eventually present themselves as electrical interconnect failures. Recent research has
shown that this failure mode is strongly affected by the grain structure size of the Al trace or
wire, and can be delayed or overcome by metallurgical modifications to the microstructure.
Other methods for reducing the effects of electromigration include limiting the current density
and minimizing flaws during the deposition process.
While electromigration has the potential to adversely affect all ICs that have Al wires with small
cross-sectional areas and operate at high current densities, the interconnect failure mechanism
would not be expected to occur simultaneously in redundant safety-related components. It is
also expected that failures in safety-related circuits due to manufacturing defects or operational
conditions would likely be detected by routine surveillance, testing, or diagnostics and that the
followup root cause analyses and corrective actions would address the generic aspects of the
failure.
It is expected that 10 CFR Part 21, Reporting of Defects and Noncompliance, would be the
method used by licensees to notify the NRC of component failures. Therefore, IC failures due
to electromigration would be reportable under 10 CFR Part 21 for safety-related instrumentation
and control components.
This information notice requires no specific action or written response. If you have any
questions about the information in this notice, please contact the technical contact listed below
or the appropriate Office of Nuclear Reactor Regulation project manager.
/RA/
William D. Beckner, Program Director
Operating Reactor Improvements Program
Division of Regulatory Improvement Programs
Office of Nuclear Reactor Regulation
Technical contact: C. Graham, NRR
(301) 415-3201 E-mail: cxg2@nrc.gov
Attachment: List of Recently Issued NRC Information Notices
DISTRIBUTION:
IN File
- See previous concurrence
DOCUMENT NAME: G:\RORP\OES\STAFF FOLDERS\FOSTER\ElectromigrationMB6261.wpd
OFFICE RE:RORP:DRIP Tech Editor EEIB:DE EEIB:DE EEIB:DE (A)SC:EEIB:DE
NAME JWFoster PKleene* CGraham KMortensen MChiramal EMarinos
DATE 10/29/2002 10/29/2002 10/29/2002 10/30/2002 10/30/2002 10/30/2002 OFFICE SC:EEIB:DE SC:RORP:DRIP PD:RORP:DRIP
NAME JCalvo TReis WDBeckner
DATE 10/30/2002 10/31/2002 10/31/2002 OFFICIAL RECORD COPY
Attachment LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
_____________________________________________________________________________________
Information Date of
Notice No. Subject Issuance Issued to
_____________________________________________________________________________________
2002-30 Control and Surveillance of 10/30/2002 All NRC licensees authorized to
Portable Gauges During Field possess, use, transport, and store
Operations portable gauges.
2002-29 Recent Design Problems in 10/15/2002 All holders of operating licenses
Safety Functions of Pneumatic or construction permits for
Systems nuclear power reactors.
2002-28 Appointment of Radiation 09/27/2002 All medical licensees.
Safety Officers and Authorized
Users Under 10 CFR Part 35
2002-27 Recent Fires at Commercial 09/20/2002 All holders of operating licenses
Nuclear Power Plants in the for nuclear power reactors, United States except those who have
permanently ceased operations
and have certified that fuel has
been permanently removed from
the reactor.
2002-26 Failure of Steam Dryer Cover 09/11/2002 All holders of operating license or
Plate After a Recent Power construction permits for nuclear
Uprate power reactors, except those that
have permanently ceased
operations and have certified that
fuel has been permanently
removed from the reactor.
2002-25 Challenges to Licensees 08/26/2002 All holders of operating licenses
Ability to Provide Prompt for nuclear power reactors, Public Notification and except those who have
Information During an permanently ceased operations
Emergency Preparedness and have certified that fuel has
Event been permanently removed from
the reactor vessel.
Note: NRC generic communications may be received in electronic format shortly after they are
issued by subscribing to the NRC listserver as follows:
To subscribe send an e-mail to <listproc@nrc.gov >, no subject, and the following
command in the message portion:
subscribe gc-nrr firstname lastname
______________________________________________________________________________________
OL = Operating License
CP = Construction Permit