The pros and cons of very-low-voltage testing: an analysis based on resistive bridging faults

Abstract

Test application at reduced power supply voltage (or VLV testing) is a cost-effective way to increase the defect coverage of a test set. Resistive short defects are a major contributor to this coverage increase. Using a probabilistic model of these defects, we quantify the coverage impact of VLV testing for different voltages. When considering the coverage increase, we differentiate between defects missed by the test set at nominal voltage and undetectable defects (flaws) detected by VLV testing. In our analysis, the performance degradation of the device caused by lower power supply voltage is accounted for. Furthermore, we describe a situation in which defects detected by conventional testing are missed by VLV testing and quantify the resulting coverage loss. We report the numbers on the increased defect coverage, flaw coverage, and coverage loss for ISCAS circuits.

Investigation into voltage and process variation-aware manufacturing test

“…[70,123], where [70] has not seen any supply voltage-dependent behaviour and [123] has observed better detection at a lowered supply voltage, these are entered into the table both for verylow-voltage and elevated voltage. Furthermore, even though the entries in Table 2.1 list the tests and supply voltage that are most effective in defect detection, some defects can manifest themselves as faults only at other supply voltage settings, particularly in case of resistive bridging faults and resistive shorts [112,114]. The fact that defects of different types manifest for different supply voltage settings indicate that testing for designs that operate on multiple supply voltage settings should be performed using more than one supply voltage to achieve high defect coverage.…”

Diagnosis of Multiple-Voltage Design With Bridge Defect

“…Next, we provide an analysis of the effect of varying supply voltage on bridge fault behavior, which explains why defects behave differently at different voltage settings [17], [18]. Fig.…”

“…The nature of bridge defects in multi-Vdd designs is such that they manifest themselves at one or more voltage settings [18]- [20]. Existing diagnosis techniques use a single Vdd setting and therefore diagnosis for multi-Vdd designs imposes a challenge as bridge defects exhibit supply voltage dependent behavior.…”

Test cost reduction for multiple-voltage designs with bridge defects through Gate-Sizing

“…2-A, which shows the relationship between the voltage on the output of gate D1 ( Fig. 1-A) and the bridge resistance for two different supply voltages V dd A and V dd B [1], [3]. Fig.…”

“…It has been shown in [3] and more recently in [9] that the fault coverage of a test set targeting resistive bridging faults can vary with the supply voltage used during test. This means that, depending on the operating Vdd setting, a given RBF may or may not affect correct operation of the design.…”