Design And Implementation Of LPDDR4 Failure Analysis Test Process Based On T5833ES

Memory plays a very important role in today's integrated circuit products.It is widely used in personal computers,various mobile terminal equipment and data centers.However,as the process becomes more advanced and the interface speed becomes faster and faster,How to ensure the product yield is becoming more and more difficult.We can locate the cause of the failure through failure analysis,and solve the problem to improve the product yield.This article firstly studied the international JEDEC standard of LPDDR4 and the types of failures that may exist in the memory.Through the analysis of the failure analysis test process of Xi'an Unil C Semiconductor Co.,Ltd.,it was found that the test process is not suitable for today's new products.The entire test process is too cumbersome to simply locate the cause of the chip failure.Therefore,this article adjusts the design ideas of the entire test process,and uses the pass failure information of different test programs to locate the possible types of failures in the memory.The test results are clear and the types of failures that may exist in the memory can be determined more accurately.For the LPDDR4 chip,algorithms such as the basic function test algorithm,row and column decoder test algorithm,horizontal line algorithm,vertical line algorithm,checkerboard algorithm,strong and weak coupling effect test algorithm were designed to detect possible faults in the chip in the paper.The algorithm can cover one or more failure models.After that,the ATL machine language supporting the automatic test machine was used to complete the writing of the program corresponding for the test algorithm.When the test program was written,the switching mode of writing and reading was used to greatly reduce the running time of the program and significantly improve the test efficiency.It greatly reduce the cost of testing.After successfully compiling all test programs,the effects of temperature,voltage,bus timing and other conditions on the chip were analyzed,and the design of the entire failure analysis test process was completed accordingly.The new test process locates the cause of the chip's failure based on the failure information after all test procedures are executed.The test results are simple and clear with extremely high accuracy.In order to ensure that there are no logical loopholes in all test programs,a good LPDDR4 chip was used to transfer the entire program package on the test machine.Finally,in order to verify the feasibility and scientificity of the test process,we used the LPDDR4 chip that failed in mass production and the Advantech T5833 ES test machine for the final test.The test results showed that this chip has no fixed faults,Conversion failure,short circuit failure,address decoding function failure and other failures,but the memory cell has abnormal leakage at high temperature,and cannot resist the impact of asymmetric array noise.The test results of the entire process show that the new failure analysis test process can locate the cause of the LPDDR4 chip failure.Comparing the failure analysis test process of Xi'an Unil C Semiconductor Co,the test results of the test process designed in the article are simple and clear.It can accurately locate the cause of the failure.The portability and scalability of the entire program package is also very high,and the program package is slightly modified.It can be applied to LPDDR4 chips of different architectures.At the same time,the test time is greatly shortened,and the test cost is reduced.It is so economical and effective that has huge engineering practical value.