Test Strategies For Pre-bond Interposer And Post-bond TSVs In 2.5D And 3D ICs

TSVs-based 2.5D/3D integration technology greatly reduces the interconnect length,increases the integrated density and bandwidth,and reduces the system power consumption.Compared with traditional two-dimensional integrated circuits,2.5D/3D integrated circuits(2.5D/3D ICs)have the advantages of low latency,low power consumption and high bandwidth.However,due to the high density integration,2.5D/3D ICs are more likely to introduce faults during the manufacturing process.For example,due to the high density of interconnect wires on interposers in the pre-bond 2.5D ICs,the interconnect wires have a high failure rate.The open-fault or short-fault in any one of the interconnect wires can cause the entire circuit to fail.Besides,for the large density of TSVs in the post-bond 2.5D/3D ICs,the possibility of crosstalk fault between TSVs is extremely great.Once a crosstalk fault occurs,the entire integrated circuit will not work normally.Therefore,in order to improve the yield of 2.5D/3D ICs,it is necessary to study and provide a low-cost and high-fault coverage test method.This paper proposes effective solutions for the interposer test in pre-bond 2.5D ICs and the TSVs test in post-bond 2.5D/3D ICs.The methods proposed in this paper are as follows: 1.Pre-bond test of interposer via auxiliary interposer and fuses in 2.5D ICs.By placing fuses and wires on the auxiliary interposer,and connecting the auxiliary interposer to the interposer under test,it can make the original inaccessible interconnects on the interposer become testable.The proposed technique only needs one auxiliary interposer.During arranging the fuse,the proposed connection strategy of inter-group e-fuses not only reduces the required number of fuses,but also enables multiple interconnects to be tested in parallel.Experimental results show that compared with the existing pre-bond interposer test scheme,the test scheme can effectively improve fault coverage that make fault coverage reach 100%,and reduce test time and test cost.2.Post-bond test and diagnosis of TSVs with crosstalk faults in the 2.5D/3D ICs.A new scheme for test and diagnosis of TSVs crosstalk faults is proposed by reusing the scan cells receiving test stimulus,which effectively reduces the TSVs test time,diagnosis time,and area overhead.The scheme firstly divides the TSVs into several groups according to the crosstalk influence distance between TSVs by the algorithm for finding the largest independent set in an adjacency matrix.In this way,the TSVs within one group will have no crosstalk faults and the number of TSVs within one group can be maximized.After grouping,all the TSVs in one group can be tested in parallel.Furthermore,the faulty TSVs can be diagnosed via test response.Experimental results show that the proposed test scheme can effectively reduce the test time,diagnosis time,and area overhead,which the test time is reduced by 38.82%,the diagnosis time is reduced by 81.94%,and the area overhead is reduced by 81.69%.