Preliminary Study on the Model of Thermal Laser Stimulation for Defect Localization in Integrated Circuits

Abstract

Thermal Laser Stimulation (TLS) is an efficient technology for integrated circuit defect localization in Failure Analysis (FA) laboratories. It contains Optical Beam-Induced Resistance Change (OBIRCH), Thermally-Induced Voltage Alteration (TIVA), and Seebeck Effect Imaging (SEI). These techniques respectively use the principle of laser-induced resistance change and the Seebeck effect. In this paper, a comprehensive model of TLS technology is proposed. Firstly, the model presents an analytical expression of the temperature variation in Integrated Circuits (IC) after laser irradiation, which quantificationally shows the positive correlation with laser power and the negative correlation with scanning velocity. Secondly, the model describes the opposite influence of laser-induced resistance change and the Seebeck effect in the device. Finally, the relationship between the current variation measured in the experiment and other parameters, especially the voltage bias, is well explained by the model. The comprehensive model provides theoretical guidance for the efficient and accurate defect localization of TLS technology.

Preliminary Study on Automatic Detection of Hard Defects in Integrated Circuits Based on Thermal Laser Stimulation

“…Figure 2 is a scheme of the hard defect scanning and testing system [18]. It includes a laser energy control unit, an image acquisition unit, a mechanical motion unit, a data acquisition unit, a computer, etc.…”

“…OBIRCH and SEI signals have negative effects on each other [18]. When the bias voltage is low, the SEI signal dominates; when the bias voltage is high, the OBIRCH signal dominates.…”

“…The Seebeck effect (SEI) signal affects the OBIRCH signal in thermal laser localization experiments [15,16]. A simulation model of OBIRCH and TIVA was proposed early [17], and there is also a study on the models of TLS [18]. However, no one has constructed a corresponding defect localization system based on an analytical model of TLS.…”