Research On Contactless Testing Of TSV Fault Using Mixed Test Stimulus

Three-dimensional stacking integration has brought a new paradigm to the semiconductor industry,in which through-silicon via(TSV)is a new interconnect technology that enables 3D integrated circuit to have the advantages of high bandwidth,low power consumption,short delay,small form factor and heterogeneous integration.However,the current TSV process technology is complex and immature,and various faults are prone to occur during the manufacturing process,which affects the yield and reliability of the 3D IC.Therefore,it is necessary to study the fault modeling and testing techniques of TSV.The size and the pitch requirements for direct TSV probing cannot be easily met by current wafer probe technologies.A contactless test method based on mixed test stimulus is proposed in this paper.The main research work is as follows:1.Signal-ground TSV pair(SG-TSV)is used as research object and contactless test structures are designed based on capacitive coupling.And the effects of the design parameter change on the signal coupled to the SG-TSV is analyzed by S-parameters in HFSS.Then the SG-TSV with contactless probe is electrically modeled and verified.2.For the void and pinhole faults,the mechanisms of the faults are analyzed and the fault physical models are established.The influences of the characteristic parameters of the faults on the signal integrity of SG-TSV are obtained by S-parameter and group delay analysis.Then,the equivalent circuits are modeled for the two faults and the analytical equations of the fault parameters are derived.Finally it is verified whether the circuits are correct by S-parameter comparison of circuit simulation and full-wave simulation.3.The mixed test stimulus is designed based on group delay,and the parameters selection rules of the main multi-tone signal are heavily studied.The response characteristics of TSV parameter faults to mixed test stimulus are obtained through simulation.4.A contactless test method based on mixed test stimulus is proposed,and the crest factor(CF)is used as the test index.Specifically,the mixed test stimulus is applied to the TSV under test through contactless probe,and the output response is obtained by the detector.The CF value is measured and calculated,and the fault diagnosis is performed by the difference between it and the faultless CF value.The void fault is tested as an example and the fault function is obtained.Finally,the fault test resolution is improved by changing the modulation of the multi-tone signal.