Research On Integrated Circuit Aging Mitigation And PCB Defect Detection

With the development level of transistors reaching nanometer size,the circuit reliability problem becomes more and more serious,and the degradation of integrated circuit functions caused by negative bias temperature instability(NBTI)becomes the most important reason.The affection of the NBTI effect to the circuit is mainly caused by the uncontrollable change of the threshold voltage of the transistor,which will large probability increase the delay of the circuit and reduce the performance of the transistor.In addition,during the soldering process of printed circuit board,defects such as missing soldering and may occur incorrect soldering,which may affect the system function.These two types of common problems may cause the life of the integrated circuit to be reduced or the circuit board not to be used normally.Therefore,the aging protection of the integratd circuit and the detection before the circuit board is put into production are essential,but the traditional aging protection method is not efficient and is subject to cost constraints.On the other hand,the manual defect detection technology method is inefficient and it is easily interfered by uncertain factors such as visual fatigue,and its reliability and stability are not highIn order to solve the above problems,the thesis does the following research on the alleviate aging technology of integrated circuits and defect detection on reliability.(1)Inserting the transmission gate(TG)at the input of the critical gate is an effective method to mitigate the NBTI effect,so the accurate identification of the critical gate is very important.In view of the lack of consideration of the influence of the output of critical gates on the subsequent logic gates in the contemporary critical gate identification methods,this thesis presents an effective critical gate measurement and identification method.This method uses path delay subtraction to re-identify critical gates,at the same time,propose an aging analysis framework using this effective measurement is proposed.Finally,the transmission gate insertion algorithm is used to protect the critical gates to alleviate the aging caused by NBTI.(2)On the basis of fully investigating and analyzing the current status of circuit board defect detection research,in view of the high cost and low efficiency of traditional printed circuit board(PCB)inspection methods,based on machine vision,a method of PCB defect detection based on digital image processing is proposed.Compare the reference method of the standard image and the image to be tested for the identification of true and false defects in PCB board defect detection.The experiments show that the average delay improvement rate of the mitigation circuit aging method in this thesis is 33.96%,compared with the contemporary method,the area is reduced by 57.94%on average,protection effect is good on the aging effect of integrated circuits.On the other hand,the defect detection method in this thesis uses the BLOB algorithm that introduces domain features,which can effectively distinguish true and false defects,and achieve fast and accurate registration of reference images and images to be tested,Improved the reliability of defect detection efficiency of integrated circuits.