Address Scrambling and Data Inversion Techniques for Yield Enhancement of NROM-Based ROMs

作者：Lu Shyue Kung^*; Li Tsu Lin; Hashizume Masaki; Chen Jiann Liang

来源：IEEE Transactions on Computers, 2015, 64(5): 1230-1240.

DOI：10.1109/TC.2014.2315639

• NROM
• fault masking
• reliability
• yield

Address scrambling and data inversion techniques are proposed for yield enhancement of NROM-based ROMs in this paper. Besides using the conventional fault replacement techniques, fault masking effects are also exploited to further improve the fabrication yield and reduce the amount of extra spare rows/columns. That is, we consider the logical effects of physical defects when the customer's code is to be programmed. A novel test and repair flow is also proposed. Based on the proposed techniques, possibilities of fault masking can be maximized. A row/column scrambling control word and a control column are used for the control of the scrambling techniques and the data inversion technique, respectively. The problem for determining the control word can be modeled with a bipartite graph. The proposed test and repair techniques can be easily incorporated into the ROM BIST architectures. This makes the proposed techniques more practical to be integrated into current design flow. According to experimental results, the fabrication yield can be improved significantly. Moreover, the incurred hardware overhead and timing penalty are almost negligible.

• 出版日期2015-5