Enhanced configurable 2-d linear feedback shift register with maximal length

Abstract

Integrated circuit (IC) testing is one of the important steps in IC manufacturing. In IC testing, various methods have been developed to generate test patterns for testing purposes. Linear feedback shift register (LFSR) is one of the famous methods with easy implementation and uses little gate counts. However, LFSR is only able to generate pseudo random patterns which do not have the capability to detect random resistant faults. Some research papers have proposed to use the modified 2-D LFSR to generate deterministic patterns. However, 2-D LFSR has limitation to generate long test patterns, which leads to the proposal of another BIST called configurable 2-D LFSR to overcome this issue. In this project, we propose an enhanced configurable 2-D LFSR with maximal length and capable of generating both deterministic and pseudo random patterns. The new design of enhanced configurable 2-D LFSR with maximal length have similar fault coverage with less hardware overhead compare with traditional configurable 2-D LFSR. This project also compares the effectiveness of the 2-D LFSR, configurable 2-D LFSR and enhanced configurable 2-D LFSR with maximal length and proposed to use a split-able maximal LFSR to further reduce test time. In conclusion, this new enhanced BIST circuit has similar fault coverage and less hardware overhead compared with traditional configurable 2-D LFSR. This proved that it successfully met the project objective.