International Business Machines Corporation

Todd Michael Burdine

Orazio Pasquale Forlenza

Donato Orazio Forlenza

William James Hurley

Phong T Tran

Franco Motika

Adrian C Anderson

Edward Emile Kelley

Peilin Song

Steven Michnowski

James Bernard Webb

Charles J Blasi

A method, apparatus and computer program product are provided for implementing deterministic based broken scan chain diagnostics. A deterministic test pattern is generated and is loaded into each scan chain in the device under test using lateral insertion via system data ports applying system clocks. Then each scan chain is unloaded and a last switching latch is identified. The testing steps are repeated a selected number of times. Then checking for consistent results is performed. When consistent results are identified, then the identified last switching latch is sent to a Physical Failure Analysis system.

implementing deterministic based broken scan chain diagnostics

Method for implementing deterministic based broken scan chain diagnostics

A method, apparatus and computer program product are provided implementing a scan chain diagnostics technique. The diagnostics technique includes employing fuses coupled to latches of the scan chain to load a known logic value into the latches at known locations of the scan chain, and then unloading values from the scan chain, and if the scan chain is defective (for example, based on the unloaded logic values), then localizing a defect in the scan chain from the unloaded logic values by comparison thereof with the known locations of the latches of the scan chain loaded with the known logic value via the fuses. The scan chain may be predesigned with fuses spaced periodically across the chain every n latches to facilitate subsequent localization of a detected defect in the scan chain.

Method, apparatus, and computer program product for diagnosing a scan chain failure employing fuses coupled to the scan chain

The Nth state of an n-stage linear feedback shift register (LFSR) used to generate pseudo random binary sequences or patterns, and which may be configured as a multiple input signature register (MISR) or single input signature register (SISR) to compress data and generate signatures, is determined by building a look-up table of n-bit states for latch positions of the linear feedback shift register; obtaining the modulo remainder of the Nth state; and generating the Nth state directly from the modulo remainder and n-bit states.

System and method for determining the Nth state of linear feedback shift registers

A method, apparatus and program product for testing at least one scan chain in an electronic chip in which the scan chain is formed by shift register latches arranged in the chain having a scan path with input pins and output pins. A flush test is executed for the scan chain under test and the flush test diagnostics for the flush test are recorded. A scan test is then executed for the scan chain under test and further test diagnostics are recorded in the event either or both the flush test or the scan test fails. The recorded flush test diagnostics and further test diagnostics are then analyzed to identify a call to one or more probable failed or failing shift register latches in the tested scan chain. The further scan chain diagnostics may include Disturb, Deterministic, ABIST, LBIST and Look-Ahead diagnostics. The tests may also be conducted for different voltage levels to determine the sensitivity of the scan chain being tested to differing voltage levels.

Method and apparatus for selective scan chain diagnostics

An apparatus, program product and method utilize an ABIST circuit provided on an integrated circuit device to assist in the identification and location of defects in a scan chain that is also provided on the integrated circuit device. In particular, a defect in a scan chain may be detected by applying a plurality of pattern sets to a scan chain coupled to an ABIST circuit, collecting scan out data generated as a result of the application of the plurality of pattern sets to the scan chain, and using the collected scan out data to identify a defective latch in the scan chain.

ABIST-assisted detection of scan chain defects

Examiner's permission under MPEP &#xa7;608.01(q) and 37 CFR &#xa7;1.125(b) is requested to submit a substitute specification and abstract. The substitute specification corrects typographical errors, grammar and formatting. No new matter has been added. The substitute specification and abstract contain no new matter to the specification of record. A marked-up version is attached along with a clean version in an appendix attached hereto.

Diagnostic method for detection of multiple defects in a Level Sensitive Scan Design (LSSD)

A method for providing interactive and iterative testing of integrated circuits including the receiving of a first failing region. The first failing region corresponds to one or more circuits on the integrated circuit. The method generates a set of adaptive algorithmic test patterns for the one or more circuits in response to the first failing region and to a logic model of the integrated circuit. Expected results for the test patterns are determined. The method includes applying the test patterns to the first failing region on the integrated circuit resulting in actual results for the test patterns. The expected results to the actual results are compared. The method also transmits mismatches between the expected results and the actual results to a fault simulator. The method includes receiving a second failing region from the fault simulator, the second failing region created in response to the mismatches and the logic model, and the second failing region corresponding to a subset of the one or more circuits on the integrated circuit.

Growing community of inventors

Wappingers Falls, NY, United States of America

Todd Michael Burdine