IEC TS 61944 pdf download – Integrated circuits – Manufacturing line approval – Demonstration vehicles

IEC TS 61944 pdf download – Integrated circuits – Manufacturing line approval – Demonstration vehicles
This technical specification establishes the characteristics of standard evaluation components(SEC) used for verifying capability and reliability.
2Standard evaluation component (SEG)
A standard evaluation component(SEC) is a test specimen especially designed or acommercial product taken from production and used for verifying capability (totally or partly)and reliability in accordance with the Process Manual.
sECs are used in the qualification test programme to define capability.
For maintenance, the tests shall demonstrate the quality aspects and either all the limits ofthe capability,or those limits of the capability used for products delivered during the mostrecent period.
Two types of components may be used as a SEC:
Type l: A component especially designed and manufactured to assess the design rules andthe manufacturing process.
Type ll: A commercial product taken from production.
Generally it is not possible to cover all limits and all quality aspects of the capability with asingle SEC.Either a single type or a combination of both types may be used, and collectivelythey shall be adequate for assessing the complete worst case design rules，the materials,manufacturing processes and the quality aspects. Where it is claimed that a diffused/metallized element,or group of elements,can demonstrate one or more limits，such anelement or group of elements shall be measurable separately without being subject toinfluence from other component elements.
The SEC shall be documented, including the design methodology and the software tools usedin the design, the functions it is to perform, its size in terms of utilized transistor or gate countand simulations of its performance.
Every SEC shall have a detail specification comprising the following requirements:
a) Complexity.: the complexity of at least one of the SEC types shall contain， as a minimum,one half the number of transistors expected to be used in the largest microcircuit to bebuilt on the qualified manufacturing line.
b) Functionality: the SEC shall contain fully functional circuits capable of being tested and
screened in a manner identical to that of qualified microcircuits.
c) Design: the SEC shall be used to test the worst case limits of geometries and electrical
design rules.The test conditions for the transistors and interconnections on the SEC shallreflect the worst case conditions.
d) Fabrication: the SEC shall be processed on a fabrication line which is intended to be, or
already is, a certified manufacturing line.
e) Packaging: the SEC shall be packaged in qualified packages according to the application
fields.
3Technology characterization vehicle (Tcv) program
The TCV program shall contain, as a minimum, those test structures needed to characterize atechnology’s susceptibility to intrinsic reliability failure mechanisms such as electromigration,time-dependent dielectric breakdown (TDDB)，hot carrier ageing，etc. lf other wear-outmechanisms are discovered as integrated circuit technology continues to mature，teststructures for the new wear-out mechanisms shall be added to the TCV program.The TCVprogram will be used for the following purposes: certification of the technology; reliabilitymonitoring; change control.
NOTE The test structures necessary to monitor intrinsic reliability failure mechanisms do not have to be on asingle die or location, but can appear on the PM(parametric monitor), on the SEC or on the device itself. The Tcvprogram should, however, indicate where the structures are located and how they are tested and analyzed.
TCV certification: For initial certification,a sufficient number of TCV test structures shall besubjected to accelerated ageing experiments for each wear-out mechanism. These teststructures shall be taken from wafers meeting the wafer screening requirements (andrandomly chosen from and evenly distributed from three homogeneous wafer lots in’thetechnology to be certified at the fabrication facility to be certified). The accelerated ageingexperiments shall produce an estimate of the MTTF(mean-time-to-failure) and a distributionof the failure times under worst case operating conditions and a circuit layout consistent withthe design rules for each wear-out mechanism. From the MTTF and distribution of failures,aworst case lifetime or a worst case failure rate can be predicted. Test structures shall betaken from completed wafers which have been glassivated. A summary of the acceleratedageing date and analysis shall be available for review by the NSI(National Standardlnspectorate).MTTF, failure distribution and acceleration factors at the initial certification willbe ‘used as bench-marks for the technology to which subsequent TCV results will becompared.Special considerations for hot carrier ageing, electromigration and time-dependentdielectric breakdown as well as ionic contamination are discussed below.
a) Hot carrier ageing: the TCV shall use structures that monitor hot carrier ageing applicable
to the technology to be used for qualified microcircuits.Device degradation is to becharacterized in terms of both grs(transconductance) and VGsT (threshold voltage)(whichever is best applicable to technology), and the resistance to hot carrier ageing is tobe based on whichever parameter experiences the manufacturer’s specified degradationlimit first for the minimum channel length allowed in the technology.
b) Electromigration: the TCV shall contain structures for the characterization of worst case
metal electromigration.
The current density and temperature acceleration factors for electromigration shall bedetermined as well as a MTTF and failure distribution for the worst case conditions.Fromthe MTTF and the distribution, a failure rate for electromigration in the technology shall becalculated.