Research On Testing Methods Of FPGA Embedded BRA

With the progress of semiconductor technology,the scale of chips is expanding,and the embedded storage resources are also increasing,Block RAM(BRAM)is a commonly used embedded memory with large capacity and fast processing speed.Because of the high repeatability and high wiring density of BRAM,it is easy to produce manufacturing defects and reduce the chip yield.At present,traditional test methods can no longer meet the test requirements of BRAM.How to test BRAM efficiently has become an important part of chip test.Although Memory built-in self-test(Mbist)will increase the hardware cost of the chip,it can effectively reduce the test time and has become the mainstream test method of BRAM.In this thesis,the Mbist of BRAM is deeply studied,and the main research contents are as follows:1.In view of the problems of low fault coverage and high test cost in the traditional test algorithm,a new March CG algorithm is proposed on the basis of March C+ algorithm.The coverage of static,dynamic,and in-word coupling faults are improved by increasing continuous read and write operation and data background.The high-efficiency Mbist circuit was constructed using the March CG algorithm,and simulation test experiments on 1Kbit×36BRAM by Modelsim.Compared to the March C+ algorithm,the fault coverage of static faults and dynamic faults is respectively improved 23.8% and 27.3%.2.Aiming at the problems of low fault coverage,poor flexibility of the common Mbist method,a new programmable Mbist method based on finite state machine is proposed.The programmable control module and the algorithm module integrating eight test algorithms are designed to improve the fault coverage and flexibility.The programmable Mbist circuit is designed with Verilog language,and the simulation experiment of 1Kbit×36 BRAM is carried out with Modelsim.Compared with the common Mbist test method,the proposed method can accurately locate the fault location,and the fault detection rate has been improved by15.625%,and the problem of poor flexibility has also been greatly improved.3.Aiming at the problem of slow speed and manual repetitive operation in board-level test,the programmable Mbist method is applied to the Automatic Test Equipment(ATE).The test vector compression techniques and reconfiguration techniques are introduced,the whole process of ATE test system development is designed,and the engineering batch test is realized,which is easy to transplant and universal.