A scan chain test device and its implementation method

Abstract

The invention discloses a scan chain test device and a realizing method; the scan chain test device comprises a scan chain logic circuit, an input decryption module, and an output encrypting module; the input decryption module is used for decoding inputted encryption data, and inputting decoded data to the scan chain logic circuit; the output encrypting module is used for encoding and outputting the data outputted by the scan chain logic circuit. The device and method can decode / encode the input and output data of the scan chain test circuit, thus testing scan chain performance correct, and ensuring chip internal data safety. In addition, the method and device can fully add all internal data of the integrated circuit into safety protection, thus providing wider test coverage ability and safety coverage ability.

Description

Technical field [0001] The invention relates to the field of integrated circuit design for test (DFT), in particular to a scan chain test device and an implementation method. Background technique [0002] As the scale of integrated circuit design becomes larger and smaller, the size of the process becomes smaller and smaller, and the ever-increasing integration level also increases the cost and difficulty of production test. Scan chain test method is an important design for test (DFT) Means, widely used to improve chip quality and yield. According to the scan chain test principle, the correctness test of the internal circuit can be completed, but it also brings security risks. Since the scan chain circuit connects all the registers in the integrated circuit in series, through the shift method, the scan chain input can send any value to any register of the circuit, and the input data is the response after the internal circuit completes the test logic function Data can be externa...

AI Technical Summary

Problems solved by technology

[0004] In other existing technologies, the method of controlling the scan chain test mode does not protect the most secure and sensitive data in the scan chain, and the test mode can be skipped through FIB (Focused Ionbeam) and other methods When protected, the original state of the data is still exposed to the outside

At the same time, since most of the scan chain tests are performed in third-party factories, the scan chain test mode needs to be shared with third parties, so the protection mode of the scan chain test mode is still in an unsafe state

However, the method of security division inside the integrated circuit will lead to the fact that the circuits that are not divided into the scan chain are not subjected to functional analysis for production testing, and there are also circuits that enter the scan chain that are completely unprotected.

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