Contactless Test Access Mechanism for 3D IC

3D IC integration presents many advantages over the current 2D IC integration. It has the potential to reduce the power consumption and the physical size while supporting higher bandwidth and processing speed. Through Silicon Via’s (TSVs) are vertical interconnects between different layers of 3D ICs with a typical 5μm diameter and 50μm length. To test a 3D IC, an access mechanism is needed to apply test vectors to TSVs and observe their responses. However, TSVs are too small for access by current wafer probes and direct TSV probing may affect their physical integrity. In addition, the probe needles for direct TSV probing must be cleaned or replaced frequently. Contactless probing method resolves most of the TSV probing problems and can be employed for small-pitch TSVs. In this dissertation, contactless test access mechanisms for 3D IC have been explored using capacitive and inductive coupling techniques. Circuit models for capacitive and inductive communication links are extracted using 3D full-wave simulations and then circuit level simulations are carried out using Advanced Design System (ADS) design environment to verify the results. The effects of cross-talk and misalignment on the communication link have been investigated. A contactless TSV probing method using capacitive coupling is proposed and simulated. A prototype was fabricated using TSMC 65nm CMOS technology to verify the proposed method. The measurement results on the fabricated prototype show that this TSV probing scheme presents -55dB insertion loss at 1GHz frequency and maintains higher than 35dB signal-to-noise ratio within 5µm distance. A microscale contactless probe based on the principle of resonant inductive coupling has also been designed and simulated. Experimental measurements on a prototype fabricated in TSMC 65nm CMOS technology indicate that the data signal on the TSV can be reconstructed when the distance between the TSV and the probe remains less than 15µm

Contactless transmission of measurement information between sensor and conditioning electronics

4Contactless transmission can be, in a lot of cases, a good answer when the measurement environment has characteristics unsuitable for the classical cable-transmission. In this article the contactless transmission problem is analyzed also when the distance between readout circuit and sensor circuit changes. A new measurement method that comprise also the evaluation of the distance is proposed. A parameter, that has a very little sensitivity to sensing capacitance and high sensitivity to the distance, is identified. The measurement method has been tested in the laboratory and the experimental results are reported.nonenoneMARIOLI D.; SARDINI E.; SERPELLONI M.; TARONI A.Marioli, Daniele; Sardini, Emilio; Serpelloni, Mauro; Taroni, Andre

Contactless transmission of measurement information between sensor and conditioning electronics

In many cases, contactless transmission can be a solution to applications where the measurement environment has characteristics that are unsuitable for the classical cable transmission. In this paper, the contactless transmission problem is analyzed when the distance between the readout and the sensor circuits changes. A model of the system, which considers the effect of the parasitic capacitance and the change of coupled and leakage fluxes, is proposed. A simulation of the theoretical analysis on the developed model shows that one frequency is more sensitive to the transducer capacitance and has no dependence on stray capacitance. A parameter that has very little sensitivity to sensing capacitance and high sensitivity to distance is identified. The measurement method has been tested in the laboratory, and the relative experimental results are reported