The Through Silicon Via Test Solution Based On The Ring Oscillator

The traditional two-dimensional integrated circuits can not achieve further performance improvement by reducing their size.Moore's law is gradually failing.In order to continue Moore's law and further improve the performance of integrated circuits,the concept of three-dimensional integrated circuits has been proposed.Different from traditional two-dimensional integrated circuits,three-dimensional integrated circuits stack modules vertically by through-silicon-vias in order to reduce the length of interconnects,reduce parasitic parameters and improve the performance of integrated circuits.Through-silicon-via is one of the most important devices in three-dimensional integration.Because of its high density and vulnerability,the traditional probe structure is not suitable for testing through-silicon-vias.How to test through-silicon-vias to improve chip yield and monitor process is an important issue in three-dimensional integrated circuits.In this paper,through-silicon-via testing in three-dimensional integrated circuits is studied.In this paper,the electrical modeling of through-silicon-vias is studied firstly,because the fault diagnosis of through-silicon-vias is carried out by means of electrical methods.Previous literatures often deviate from the physical size of through-silicon-vias and study silicon through-hole testing,and only using the method of formula analysis leads to inaccurate electrical model.In this paper,the physical model of through-silicon-vias is analyzed by three-dimensional full-wave simulation software.The equivalent electrical model of through-silicon-vias obtained by simulation software will be more accurate.Then the fault is injected into the physical model of through-silicon-vias to study the effect of the fault on the equivalent electrical model of through-silicon-vias.The simulation results show that the equivalent resistance of through-silicon-vias increases due to the void fault of through-silicon-vias,and the leakage fault of through-silicon-vias leads to the decrease of the dielectric layer resistance and equivalent capacitance formed by through-silicon-via and silicon substrate.The RC ring oscillator increases the period of the ring oscillator by adding RC circuit to the ring oscillator.Moreover,the variation of the output period of the RC ring oscillator increases when the leakage fault occurs in the through-silicon-via,which makes the weaker leakage fault can be detected.The simulation structure shows that the RC ring oscillator can detect leakage faults of 0.2?m~2 or more.The Schmidt ring oscillator replaces the inverters at the through-silicon-via receiving end with Schmidt flip-flops.Both theoretical analysis and simulation results show that Schmidt flip-flop with high forward threshold and low reverse threshold is advantageous to the detection and diagnosis of void faults.The simulation results show that the period of the ordinary ring oscillator varies by 384 picoseconds when the void resistance of the through-silicon-via is 30K?and the void fault is located in the middle part of the through-silicon-via.The period of the Schmidt ring oscillator varies by 884 picoseconds,which is better than that of the ordinary ring oscillator.For leakage faults,a voltage dividing circuit is realized by using an inverter on Schmidt flip-flop to diagnose leakage faults of the through-silicon-via.This method has high sensitivity to leakage faults of the through-silicon-via.The simulation results show that when the leakage fault of 1?m~2 occurs in the the through-silicon-via,the max voltage of the upper end node of the the through-silicon-via changes by 0.078V.