Patent ID: 8159814

Claim:
A method of operating a semiconductor device, the method comprising: operating said semiconductor device for a first period of time at a normal operating mode; recording conditions of said semiconductor device during said first period of time; calculating a wearout amount (WA) caused during said first period of time at said normal operating mode; operating said semiconductor device for a second period of time at a repair mode after said first period of time at said normal operating mode, said repair mode being different from said normal operating mode; calculating a repair amount (RA) provided during said second period of time at said repair mode; recording a net wearout amount (NWA) by subtracting said RA from said WA; terminating said repair mode, if said NWA drops below a pre-determined value, making said second period of time shorter than a time period available from an end of said first period of time to a beginning of a third period of time; and operating said semiconductor device for said third period of time at said normal operating mode after said second period of time at said repair mode.