Non-Volatile Memory Verification with Selective Pass Masking

The patent segments the verification process by dividing threshold voltage levels into different groups (first group and second group). The first group undergoes comprehensive pass bit masking verification to ensure high accuracy, while the second group uses a simplified verification process that counts program failures without full masking. This segmentation allows the system to maintain verification accuracy for critical threshold levels while reducing overall programming time through the optimized verification of other levels.

The patent applies different verification qualities to different groups based on their specific needs. The first group, which requires high verification precision, receives comprehensive pass bit masking operations. The second group, where high precision is less critical, receives a simplified verification process that counts program failures without performing full masking operations. This local quality approach ensures that resources are consumed only where necessary for high-precision verification, thereby reducing overall resource consumption while maintaining adequate verification precision.