An Online Self-Healing Research Based On ECC And BISR For Embedded RAM

With the continuous development of integrated circuit technology,the integration degree of SoC chips is getting higher and higher,hundreds of millions of transistors can be integrated on a mobile phone chip,and the probability of chip failure also increases.Among them,the largest area is the embedded memory.Therefore,it is more and more important to test and repair embedded memory during chip manufacturing,leaving factory and using.Especially online test and repair during use,problems that are difficult to find in offline test can be found,faults can be quickly repaired,and the service life of the memory can be improved.Therefore,how to better realize the online test and self-healing of embedded memory has become an important issue in the current research,and it is also the main issue of this article.The main research contents of this article are as follows:(1)The fault type of the embedded memory is studied,especially for the aging process,the fault occurrence address is recorded,and the classification method according to the transient fault,intermittent fault and permanent fault is used for classification,which is convenient for the subsequent prediction of the fault;(2)The online built-in self-test of the memory is studied,and an improvement is made on the basis of the original test scheme,and a temporary memory test method with a small area is proposed.The March C-algorithm in the offline test is used for testing,but the data in the test unit is backed up with temporary registers first.In the test process,in order to reduce the temporary memory area and cover test failures,a pair-by-test method of storage units is used,so that only two words need to be backed up each time,and coupling failures between all units can be tested;(3)The aging test is performed on the memory,and a fault prediction model was established by simulation.The weibull distribution was used to fit the fault occurrence.The probability of the fault was predicted according to the fault occurrence law and the fitted function curve.The memory repair was performed according to the fault occurrence probability.(4)Combining the proposed online test method with ECC technology and redundant allocation technology to design a complete set of memory fault self-healing mechanisms.Contains a complete set of mechanisms from detection to repair and prevention to maximize the stability of the memory and extend the life of the memory.