Advanced Micro Devices Corporation

Other

Spansion Llc.

Edward V Bautista, Jr

Weng Fook Lee

Ken Cheong Cheah

Colin Stewart Bill

Santosh K Yachareni

Feng Q Pan

Darlene G Hamilton

Boon Tang Teh

Azrul Halim

Kazuhiro Kurihara

Pau-Ling Chen

Ravi S Sunkavalli

Allan Parker

Shigekazu Yamada

Bhimachar Venkatesh

Joseph Kucera

Keith H Wong

Syahrizal Salleh

Murni Mohd-salleh

Tan Tat Hin

Chi-Mun Ho

Weng F Lee

Methods for recycling unused error correction code (ECC) during flash memory programming, comprise generating ECC from user data to form a syndrome and storing the syndrome into volatile memory. ECC is re-encoded corresponding to the syndrome read from the memory with new user data. Re-encoding ECC comprises comparing new ECC with the most recent ECC of the previous syndrome, correcting a bit error in the new ECC, and indicating if the new ECC has failed.

Implementation of recycling unused ECC parity bits during flash memory programming

Methods and apparatus are disclosed for erasing a core memory cell using a negative gate voltage in a semiconductor memory device, wherein negative pump MOS regulation capacitors are pre-charged according to a pre-charge signal during a core cell erase operation. A negative voltage pump is then regulated using the pre-charged negative pump MOS regulation capacitors to provide the negative gate voltage. Apparatus is disclosed for pre-charging negative pump MOS regulation capacitors during a core cell erase operation in a memory device, which comprises a switch connected between a reference voltage and the negative pump MOS regulation capacitors, and a pre-charge control circuit providing a pre-charge signal to the switch to selectively connect the reference voltage to the negative pump MOS regulation capacitors for pre-charging thereof in an erase operation.

Method and apparatus for pre-charging negative pump MOS regulation capacitors

In a method and system for diagnosing a back-end state machine used for testing flash memory cells fabricated on a semiconductor substrate, a signal selector and a diagnostic matching logic are fabricated on the semiconductor substrate. The diagnostic matching logic sets a generated match output to a pass or fail state depending on control variables from the back-end state machine. The signal selector selects the generated match output to be used in a verify step of a BIST (built-in-self-test) mode, if a diagnostic mode is invoked. The back-end state machine performs a plurality of BIST modes with the generated match output, for testing the functionality of the back-end state machine.

Diagnostic mode for testing functionality of BIST (built-in-self-test) back-end state machine

An address sequencer is fabricated on a semiconductor substrate having flash memory cells fabricated thereon for sequencing through the flash memory cells during BIST (built-in-self-test) of the flash memory cells. The address sequencer includes an address sequencer control logic and address sequencer buffers fabricated on the semiconductor substrate. The address sequencer buffers generate a plurality of bits indicating an address of the flash memory cells. The address sequencer control logic controls the buffers to sequence through a respective sequence of bit patterns for each of a plurality of BIST modes.

Address sequencer within BIST (Built-in-Self-Test) system

A memory device and a method for compensating for a load current in the memory device. The memory device includes a plurality of I/O buffers where each I/O buffer includes an I/O write-buffer driver circuit. The I/O write-buffer driver circuit is coupled to a load current compensation circuit. Although each I/O buffer includes an I/O write-buffer circuit, a single load current compensation circuit may be coupled to several I/O write-buffer driver circuits. The load current compensation circuit generates a load compensation current for each I/O buffer circuit that is not being programmed. The load compensation current increases the load current so that a drain-side programming voltage (VPROG) drives a substantially constant load current, wherein the drain-side programming voltage is substantially independent of the number of bits being programmed.

Memory device and method

A memory device and a method for refreshing the memory device. The memory device includes a memory cell capable of storing two bits of data. One bit is referred to as the normal data bit and the other bit is referred to as the complementary data bit. Each memory cell has an associated dynamic reference cell. The normal data is refreshed by latching refresh data into a data latch and ORing the latched data with input data. The refresh data is written to the corresponding memory location. The data for the complementary data bit is refreshed by latching complementary data bit refresh data into the complementary data latches and writing to the memory cell. The normal and complementary data bits are refreshed before each read operation.

In a method and system for providing a CAM (content addressable memory) cell of a flash memory device, a respective core flash memory cell to be used as the CAM cell is fabricated as part of a core array of the flash memory device. In addition, the respective core flash memory cell is accessed from the core array as the CAM cell for a CAM function within the flash memory device. Components used for supporting operation of the core array are also used for accessing the core flash memory cells of the additional sector for such CAM functionality. Thus, CAM functionality is provided with a minimized number of components and with minimized area of the die of the flash memory device. In addition, because the CAM cells are implemented as core flash memory cells of the core array, the CAM cells may reliably undergo more numerous programming and erasing cycles.

CAM (content addressable memory) cells as part of core array in flash memory device

A method for erasing a flash memory. In a flash memory device having multiple sectors a plurality of sectors is selected for erase (). a subset of sectors is selected () and an erase pulse is applied simultaneously to all sectors in the subset (). After the application of an erase pulse having an initial voltage value, at least one sector of the subset is verified (). If there is at least one unerased cell in the verified sector, the erase voltage is adjusted () and another erase pulse is applied to the subset of sectors (). The adjustment of the erase voltage may be a function of the number of times that an erase pulse has been applied to the subset. This cycle is repeated on the subset until the selected sector is verified as erased. After a sector is verified, the erase/verify cycle is applied to one or more of the remaining sectors in the subset until each of the remaining sectors has been verified as erased. After all of the sectors in the subset are erased, the erase voltage is reset to its initial value () and another subset of sectors is selected for erase/verify as described above (). The process may be repeated until all of the memory sectors in the device have been erased (). A flash memory device with embedded logic may be used to execute the method.

System and method for erase voltage control during multiple sector erase of a flash memory device

A method of implementing a reference current measurement mode within a reference array programming mode or a reference array erase mode in a semiconductor chip is disclosed. This implementation leads to significant reduction in testing time for the semiconductor chip, increasing production volume and revenues.

Implementing reference current measurement mode within reference array programming mode or reference array erase mode in a semiconductor

In a method and system for monitoring erase pulses applied on a sector of flash memory cells fabricated on a semiconductor substrate, a pulse counter and a pulse counter controller are fabricated on the semiconductor substrate. The pulse counter controller inputs a maximum number and outputs an indication of a sector fail if the flash memory cells of the sector do not pass erase verification with less than the maximum number of erase pulses applied on the sector during an erase verify BIST (Built-in-Self-Test) mode. In one example, the maximum number is a percentage of a diagonal total number of erase pulses needed to be applied on the sector until each flash memory cell at a diagonal location of the sector passes erase verification.

On-chip erase pulse counter for efficient erase verify BIST (built-in-self-test) mode

In a method and system for repairing defective flash memory cells fabricated on a semiconductor substrate, a repair controller and a plurality of voltage sources are fabricated on the semiconductor substrate. The repair controller controls the voltage sources to apply programming voltages on respective CAM (content addressable memory) flash memory cells in a JUICE state for replacing the defective flash memory cells with a corresponding redundancy element of flash memory cells. In addition, a FAILREP logic is fabricated on the semiconductor substrate for entering a HANG state if no redundancy element of flash memory cells is available or if the defective flash memory cells have been previously repaired.

On-chip repair of defective address of core flash memory cells

There is provided an improve BIST frontend state machine and a method for micro-architectural implementation of the same which is achieved with a minimal amount of test logic circuitry. The state frontend machine includes a state controller responsive to clock signals, control signals, and output register signals for generating output state signals based upon a fixed number of states utilizing death logic so as to sequence through one of a plurality of sets of tests until completed or failed. A substantial savings of approximately 40% in the I.C. chip area was realized in comparison to the implementation by a conventional state machine.

Method of micro-architectural implementation on bist fronted state machine utilizing 'death logic' state transition for area minimization

There is provided a tester interface circuit for use with a BIST state machine and a method for micro-architectural implementation of the same so as to enable cycling through a BIST test. The tester interface circuit includes a storage device, a logic decoder, a set/clear mechanism, and a polling logic device. The tester interface circuit is implemented with a minimum amount of chip area on a semiconductor IC.

Method of micro-architectural implementation of interface between bist state machine and tester interface to enable bist cycling

A wait system for a memory device is operative to provide a wait signal to delay performance of each operation relative the memory cell. The wait signal initially delays performance of at least one initial operation relative the memory cell during a given user mode by a first duration. After the initial wait signal, a subsequent wait signal is provided to delay performance of subsequent operations relative the memory cell during the given user mode by a second duration, which is less than the first duration.

System and method to facilitate stabilization of reference voltage signals in memory devices

Methods and apparatus are disclosed for verifying soft programming of one or more memory cells in a memory device. The methods comprise providing a voltage source to the core cell gate, and verifying soft programming of the cell after overshoot in the regulated voltage source has settled. Also disclosed are memory devices having a logic circuit providing a regulated voltage source to the cell gate during a soft program verify operation, and a sensor to verify soft programming of the cell when a first voltage is applied to the gate from the regulated voltage source. The logic circuit provides a soft program verify signal to the sensor to verify soft programming after overshoot in the voltage source has settled.

Growing community of inventors

Santa Clara, CA, United States of America

Edward V Bautista, Jr