Voltage controlled oscillator, and test system and test method for detecting technological fluctuation

Abstract

The invention belongs to the technical field of microelectronics, and in particular relates to a VCO (voltage controlled oscillator), and a test system and a test method for detecting technological fluctuation. The VCO comprises a ring oscillator and a current controlled MOS (Metal Oxide Semiconductor) tube, wherein the ring oscillator comprises odd number of CMOS (Complementary Metal-Oxide-Semiconductor Transistor) phase inverters; a bias voltage is input at a grid end of the current controlled MOS tube so that the current controlled MOS tube is worked in a sub-threshold region, the current flowing through one CMOS phase inverter is further controlled, and therefore the output frequency of the VCO reflects the threshold voltage of the current controlled MOS tube. The test system is formed based the VCO. The random fluctuation value of the threshold voltage among different MOS tubes inside a chip is tested by using the test method provided by the invention. The VCO has the advantages that a circuit is simple and the digitization is easy to achieve. When the technological fluctuation is tested by using the testing system based on the VCO, the random fluctuation value of the threshold voltage with high sensitivity can be obtained, and the test accuracy is good.

Description

technical field [0001] The invention belongs to the technical field of microelectronics and relates to the detection of chip process fluctuations, in particular to a voltage-controlled oscillator (Voltage Control Oscillator, VCO)-based test system and a test method for detecting process fluctuations. Background technique [0002] With the continuous development of microelectronics manufacturing technology, the feature size of the device is getting smaller and smaller, and the size of the process generation is also getting smaller and smaller. Despite the continuous development of chip manufacturing technology, the problem of random process fluctuations is inevitable, and even its impact on chip performance cannot be ignored. [0003] Generally, process fluctuations are caused by slight process errors between the same batch or between different batches, which will also cause slight changes in the structural parameters of the device, for example, MOS (Metal Oxide Semiconductor...

AI Technical Summary

Problems solved by technology

[0008] (3) Output voltage V OUT is an analog signal, the output of the analog signal requires a buffer (buffer), and the introduced buffer will generate errors, which will easily lead to V OUT unreal

At the same time, the circuit for this test is an analog circuit as a whole, and it is difficult to guarantee its normal operation after it is prepared in the early process

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