# US 12,190,934 B2 · Memory with row hammer mitigation technique

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- Number: US 12,190,934 B2
- Document ID: US12190934B2
- Status: Granted
- Kind: B2
- Application number: 17/704,714
- Filed: 2022-03-25
- Published: 2023-05-25
- Granted: 2025-01-07
- Earliest claimed: 2021-11-23
- Assignees: SK hynix Inc.
- Applicants: SK hynix Inc.
- Inventors: Woongrae Kim; Hoiju Chung
- Web page: https://patentgrep.com/patent/US12190934B2

## CPC

- G11C 11/40603: {Arbitration, priority and concurrent access to memory cells for read/write or refresh operations}
- G11C 11/40615: {Internal triggering or timing of refresh, e.g. hidden refresh, self refresh, pseudo-SRAMs}
- G11C 11/40611: {External triggering or timing of internal or partially internal refresh operations, e.g. auto-refresh or CAS-before-RAS triggered refresh}
- G11C 11/40622: {Partial refresh of memory arrays}
- G11C 11/4076: Timing circuits (for regeneration management G11C11/406)
- G11C 11/4078: Safety or protection circuits, e.g. for preventing inadvertent or unauthorised reading or writing; Status cells; Test cells (protection of memory contents during checking or testing G11C29/52)
- G11C 2211/4062: Parity or ECC in refresh operations
- G11C: STATIC STORES (semiconductor memory devices H10B)

## Abstract

A memory includes: a memory core; a list storage circuit suitable for storing a weak row list of rows that are vulnerable to a row hammer attack in the memory core; and a row hammer attack detection circuit suitable for selecting rows that are row-hammer-attacked among rows in the memory core as hammered rows, and increasing a probability that the rows stored in the list storage circuit are selected as the hammered rows.

## Claims

### Claim 1

A memory comprising:
a memory core;
a list storage circuit suitable for storing a weak row list that includes a list of rows that have been determined to be more vulnerable to a row hammer attack and data loss, as compared to other rows in the memory core also row hammered attacked, wherein the rows more vulnerable to the row hammer attack are divided into multiple levels according to a degree of vulnerability; and
a row hammer attack detection circuit suitable for selecting rows that are row-hammer-attacked among rows in the memory core as hammered rows,
wherein the row hammer attack detection circuit increases a probability that the rows in the list of rows that have been determined to be more vulnerable to a row hammer attack and data loss in the list storage circuit are selected as the hammered rows.

### Claim 2 (depends on 1)

The memory of claim 1, wherein rows positioned adjacent to the hammered row which is selected by the row hammer attack detection circuit are refreshed during a smart refresh operation of the memory.

### Claim 3

A memory comprising:
a memory core;
a list storage circuit suitable for storing a weak row list that includes a list of rows that have been determined to be more vulnerable to a row hammer attack and data loss, as compared to other rows in the memory core also row hammered attacked, wherein the rows more vulnerable to the row hammer attack are divided into multiple levels according to a degree of vulnerability;
a sampling circuit suitable for sampling and storing a portion of active addresses used for active operations of the memory core and increasing a sampling probability of an active address corresponding to the rows stored in the list storage circuit among the active addresses; and
a selection circuit suitable for selecting one among the sampled addresses stored in the sampling circuit as a hammered row address in a predetermined order whenever a smart refresh operation is performed,
wherein the selection circuit selects, when there is an address corresponding to a row stored in the list storage circuit among the sampled addresses, the row address as a hammered row address, and
wherein the selection circuit increases a probability that the rows in the list of rows that have been determined to be more vulnerable to a row hammer attack and data loss in the list storage circuit are selected as the hammered rows.

### Claim 4 (depends on 3)

The memory of claim 3, wherein the sampling circuit includes:
a random pulse generator suitable for generating a random pulse; and
a register circuit suitable for sampling and storing a row address when an active signal is activated in an activation period of the random pulse.

### Claim 5 (depends on 3)

The memory of claim 3, wherein the selection circuit selects, when there are a plurality of addresses corresponding to the rows stored in the list storage circuit among the sampled addresses, one among the corresponding addresses as a hammered row address in a predetermined order whenever the smart refresh operation is performed.

### Claim 6 (depends on 3)

The memory of claim 3, wherein rows positioned adjacent to the hammered row which is selected by the selection circuit are refreshed during a smart refresh operation of the memory.

### Claim 7 (depends on 1)

The memory of claim 1, wherein the row hammer attack detection circuit includes
a sampling circuit suitable for sampling and storing a portion of active addresses used for active operations of the memory core and increasing a sampling probability of an active address corresponding to the rows stored in the list storage circuit among the active addresses.

### Claim 8 (depends on 1)

The memory of claim 1, wherein, in the list storage circuit, the list of rows determined to be more vulnerable than other rows in the memory device also row attacked is determined at a time of manufacture of the memory device.

### Claim 9

A memory comprising:
a memory core;
a list storage circuit suitable for storing a weak row list of rows that are determined to be more vulnerable to a row hammer attack, as compared to the other rows in the memory core, wherein the rows more vulnerable to the row hammer attack are divided into multiple levels according to a degree of vulnerability; and
a row hammer attack detection circuit suitable for selecting rows that are row-hammer-attacked among rows in the memory core as hammered rows and increasing a probability that the rows stored in the list storage circuit are selected as the hammered rows,
wherein the row hammer attack detection circuit samples the other rows, except the rows stored in the list storage circuit, with a low probability when an active operation is performed while the rows stored in the list storage circuit are sampled with a high probability.