Patent ID: 6498752
Filing Date: 2002-12-24
Classification: G11C

Abstract:
A method for erasing a Flash memory, comprising:a) applying an erase pulse to increase a threshold voltage of a memory cell of a flash memory, b) verifying that the threshold voltage is greater than a first predetermined value after application of said erase pulse, c) repeating the application of an erase pulse if the threshold voltage is less than said first predetermined value until said threshold voltage is greater than said first predetermined value, d) applying a reverse program to decrease said threshold voltage of said memory cell, e) verifying that said threshold voltage is below a second predetermined value after application of said reverse program, f) repeating said reverse program if the threshold voltage is greater than said second predetermined value until said threshold voltage is less than said second predetermined value, g) verifying that said threshold voltage is greater than a third predetermined value after said reverse program operation is complete, h) correcting said threshold voltage to be greater than said third predetermined value if said threshold voltage is less than said third predetermined value.