阅读说明：本技术 半导体存储器装置 (Semiconductor memory device with a memory cell having a plurality of memory cells ) 是由 冈田敏治 于 2019-07-19 设计创作，主要内容包括：本发明涉及半导体存储器装置。提供了能够在短时间内输出示出存储器单元的通常块和缺陷块的配置关系的数据序列的半导体存储器装置。具有：存储器部,包括具有每一个由多个存储器单元构成的多个存储器块的通常存储器区域、以及具有用于置换多个存储器块之中的作为包括缺陷单元的存储器块的缺陷块的冗余块的冗余存储器区域；存储部,将示出通常存储器区域中的缺陷块的位置的缺陷地址信息与作为该缺陷块的置换对象的冗余块的位置对应起来存储；以及输出电路,根据数据读出信号,基于存储部中存储的信息,输出示出通常存储器区域的至少一部分的区域中的缺陷块与缺陷块以外的块的配置关系的由2值的数据构成的数据序列。(A semiconductor memory device capable of outputting a data sequence showing an arrangement relationship between a normal block and a defective block of memory cells in a short time, the semiconductor memory device includes a memory section including a normal memory region including a plurality of memory blocks each formed of memory cells and a redundant memory region including a redundant block for replacing a defective block of the memory blocks including a defective cell, a storage section storing defect address information showing a position of the defective block in the normal memory region and a position of the redundant block to be replaced by the defective block in association with each other, and an output circuit outputting a data sequence showing an arrangement relationship between the defective block and a block other than the defective block in a region of at least parts of the normal memory region based on information stored in the storage section based on a data read signal.)

A semiconductor memory device of the kind 1, , comprising:

a memory unit including a normal memory area including a plurality of memory blocks each including memory cells, and a redundant memory area including a redundant block having another address, the redundant memory area being an area for replacing an access to a defective block among the plurality of memory blocks with an access to the other address;

a storage unit that stores address information indicating a position of the defective block in the normal memory area in association with address information indicating a position of a redundant block to be replaced with the defective block; and

and an output circuit that outputs a data sequence of 2-valued data indicating an arrangement relationship between the defective block and a memory block other than the defective block in the normal memory area for at least an area of parts of the normal memory area based on the information stored in the storage unit, based on a data read signal.

2. The semiconductor memory device according to claim 1, wherein the output circuit generates the data sequence based on a distribution pattern of the 2-value data occurring in the memory portion, assuming that -value data among the 2-value data are written to a redundant block corresponding to the defective block and another -value data are written to a memory block other than the defective block of the normal memory area.

3. The semiconductor memory device according to claim 2, wherein the output circuit receives the data read signal and an address designation designating an area of the at least part of the normal memory area, extracts a distribution pattern corresponding to the area designated by the address designation from a distribution pattern of the 2-valued data appearing in the memory portion, and outputs the extracted distribution pattern as the data sequence.

4. The semiconductor memory device according to any of claims 1 to 3, wherein the output circuit is configured to be switched to a1 st output mode or a2 nd output mode in response to a designation of an output mode,

when the 1 st output mode is designated, the data sequence is output based on the data read signal, and when the 2 nd output mode is designated, the information actually written in the memory unit is output based on the data read signal.

A semiconductor memory device of the kind described in 5, , comprising:

a memory unit including a normal memory area including a plurality of memory blocks each including memory cells, and a redundant memory area including a redundant block having another address, the redundant memory area being an area for replacing an access to a defective block among the plurality of memory blocks with an access to the other address;

a storage unit that stores address information indicating a position of the defective block in the normal memory area in association with address information indicating a position of a redundant block to be replaced with the defective block; and

and a fixed value write circuit for writing values of data among the 2-value data into a redundant block corresponding to the defective block and another values of data into a memory block other than the defective block in the normal memory area based on the information stored in the storage unit in accordance with a data write start signal.

Technical Field

The present invention relates to a semiconductor memory device.

Background

In a manufacturing process of a semiconductor Memory such as a DRAM (Dynamic Random Access Memory), a test for determining the quality of the semiconductor Memory is performed in a wafer test process of a wafer on which the semiconductor Memory is formed. In such a test, memory cells that do not satisfy the prescribed operating conditions are detected as failing cells. In a semiconductor memory, a redundant area is provided in addition to a normal memory area, and a memory cell determined as a defective cell in a test is replaced with a cell (redundant cell) in the redundant area. That is, when an access is tried for an address of a defective cell, an access is made to an address of a redundant cell instead of the defective cell. If a larger number of defective cells than the number of redundant cells are detected, the semiconductor memory is determined to be defective.

In addition, in order to improve the detection rate of fail bits in a semiconductor memory and improve testability, parallel tests of an expected value comparison method are performed, and in parallel tests of an expected value comparison method, data read from memory cells is compared with expected value data, and in this case, parallel tests of an expected value comparison method are performed on a normal memory cell that is not a redundant cell, and therefore, when a redundant region is accessed, there is a problem in that an expected value becomes unclear.

Disclosure of Invention

Problems to be solved by the invention

In the case of performing a test by the method of the above-described conventional technique, it is necessary to acquire information indicating which memory cell is replaced with a redundant cell. However, when acquiring this information, it is necessary to write data in advance into the normal area and the redundant area and to repeat a process of issuing a write command corresponding to writing of each memory cell from the outside of the DRAM by a DRAM controller or the like for each memory cell, as preparation for the writing, and therefore, there is a problem that it takes time to write.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a semiconductor memory device capable of outputting a data sequence showing an arrangement relationship between a normal block and a defective block of a memory cell in a short time.

Means for solving the problems

A semiconductor memory device includes a memory including a normal memory area including a plurality of memory blocks each including memory cells and a redundant memory area including a redundant block having a defective block among the plurality of memory blocks, the redundant memory area being an area for replacing an access to an address of the defective block with an access to another address, a storage unit storing address information indicating a position of the defective block in the normal memory area and address information indicating a position of the redundant block to be replaced by the defective block in association with each other, and an output circuit outputting a data sequence including 2-valued data indicating an arrangement relationship between the defective block and a memory block other than the defective block in the normal memory area in an area of at least parts of the normal memory area based on information stored in the storage unit in accordance with a data read signal.

The semiconductor memory device of the present invention includes a memory including a normal memory area including a plurality of memory blocks each including memory cells, and a redundant memory area including a redundant block having a defective block among the plurality of memory blocks, the redundant memory area being an area for replacing an access to an address of the defective block with an access to another address, a storage unit storing address information indicating a position of the defective block in the normal memory area in association with address information indicating a position of the redundant block to be replaced by the defective block, and a fixed value write circuit writing values of data among 2 values of data to the redundant block corresponding to the defective block and writing another values of data to a memory block other than the defective block in the normal memory area based on information stored in the storage unit in accordance with a data write start signal.

Effects of the invention

According to the semiconductor memory device of the present invention, it is possible to output a data sequence showing the arrangement relationship of normal blocks and defective blocks of memory cells in a short time.

Drawings

Fig. 1 is a block diagram showing the structure of a semiconductor memory device of embodiment 1.

Fig. 2A is a diagram showing the structure of a memory cell.

Fig. 2B is a diagram schematically showing an image in the case where a redundant area is used.

Fig. 3A is a diagram showing a memory area in the case where "0" is written to the cells of the normal area and "1" is written to the cells of the redundant area.

Fig. 3B is a diagram schematically showing access to a normal block and a redundant block.

Fig. 4 is a block diagram showing the structure of the fixed value output circuit and the flow of data.

Fig. 5 is a flowchart showing a processing routine of the data acquisition process.

Fig. 6 is a block diagram showing the structure of the semiconductor memory device of embodiment 2.

Fig. 7 is a block diagram showing the structure of the fixed value auto-write circuit and the flow of data.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail. In the following description of the embodiments and the accompanying drawings, the same reference numerals are given to substantially the same or equivalent parts.

[ example 1]

Fig. 1 is a block diagram showing the structure of a semiconductor memory device 100 of the present embodiment. The semiconductor memory device 100 is composed of, for example, a dram (dynamic Random Access memory). The semiconductor memory device 100 includes a memory region 10, a fuse 11, and a control logic circuit 12.

The memory area 10 is composed of a normal area a1 and a redundant area a 2. The normal area a1 is a memory area including memory cells to be accessed by a normal memory. The redundant area a2 is a memory area including redundant blocks to be replaced with blocks including a predetermined number or more of defective cells (hereinafter referred to as defective blocks) in the normal area a 1.

The fuse 11 functions as a storage unit that stores an address of a defective block as a "redundant address" in association with an address of a replacement destination redundant block. The fuse 11 is composed of a plurality of fuse elements, and stores information of a redundant address by cutting the fuse elements.

Fig. 2A is a diagram schematically showing the structure of the memory region 10 and the fuse 11, each of the normal region a1 and the redundant region a2 of the memory region 10 is configured by a plurality of cells, in this embodiment, addresses are assigned to the cells in the normal region a1 for each row, in the semiconductor memory device 100 of the present embodiment, the normal region a1 and the redundant region a2 have the same number of columns, and replacement from the normal cells to the redundant cells is performed for each row, that is, in the normal region a1, a defective block is configured for each row, further, in the redundant region a2, a redundant block is configured for each row, and the fuse 11 has a storage region corresponding to each row (i.e., each redundant block) of the redundant region a 2.

Fig. 2B is a diagram schematically showing an image in the case where a redundant area is used in the semiconductor memory of the present embodiment. Here, blocks of addresses PP, OO, NN, and MM of the normal area a1 are indicated by oblique lines as defective blocks.

In the fuse 11, PP, OO, NN, and MM, which are addresses of defective blocks, are set as redundant addresses and stored. Thus, the blocks of addresses PP, OO, NN, and MM of the normal area a1 are replaced with the blocks of rows 1, 2, 3, and 4 of the redundant area a2, respectively.

Referring again to fig. 1, the control logic circuit 12 includes a user IF 21, a command/address analyzing section 22, a test mode control section 23, a read/write control section 24, a redundant area use determining section 25, a fuse interface 26, a memory cell IF 27, and a fixed value output circuit 28.

The user IF 21 is an interface unit that receives a command (command signal) such as writing or reading from the outside of the semiconductor memory device 100 to the memory area 10.

The command/address analysis unit 22 analyzes what the command indicates (for example, write or read) based on the command received by the user IF 21. The command/address analysis unit 22 analyzes the address of the memory cell to which the command is directed.

The test mode control unit 23 controls the operation of each unit in the control logic circuit 12 in the test mode. For example, the test mode control section 23 switches the fixed value output function of the fixed value output circuit 28 between enabled and disabled based on a command received via the user IF 21.

The read/write control section 24 controls operations of reading and writing with respect to each memory cell of the memory area 10. The read/write control unit 24 controls the read operation or the write operation based on the command analyzed by the command/address analysis unit 22.

The redundant area use determination unit 25 determines which of the normal area a1 or the redundant area a2 of the memory area 10 is to be accessed based on the address analyzed by the command/address analysis unit 22.

The fuse interface 26 accesses the fuse 11 to determine an access destination of the memory region under the control of the read/write control section 24. Specifically, the fuse interface 26 accesses the fuse 11 in order to check whether or not the access destination block to the memory area designated by the user IF 21 is a replacement target block with the redundant block.

The memory unit IF 27 is an interface unit that accesses the memory area 10 under the control of the read/write control unit 24. The memory unit IF 27 accesses the redundant block IF the access destination block is a replacement target block with the redundant block, and accesses the memory area designated from the user IF 21 IF the access destination block is not a replacement target block.

The fixed value output circuit 28 is controlled to be active or inactive by the control of the test mode control section 23, and outputs a fixed value when active. Specifically, the fixed value output circuit 28 outputs a data sequence made up of 2-valued data showing the arrangement relationship between the defective block and the blocks other than the defective block (normal blocks) in the normal memory area a 1. For example, the fixed value output circuit 28 outputs a data sequence of "0" or "1" that occurs when data of the memory cell 1 column amount is read out continuously from the memory area 10 in a state where "0" is written to the memory cells of the normal block and "1" is written to the memory cells of the redundant block.

Fig. 3A is a diagram showing the appearance of the memory area 10 in the case where "0" is written to the memory cells of the normal block and "1" is written to the memory cells of the redundant block. The blocks of addresses PP, OO, NN and MM are replaced with redundant blocks, and therefore, in the case where there is an access to the memory cells of these blocks, data "1" is read out instead of data "0".

The read position and size of the data sequence output by the fixed value output circuit 28 are predetermined, and are supplied to the semiconductor memory device 100 as portions of information included in a command issued by a DRAM controller or the like (not shown) outside the semiconductor memory device 100, "00010010010001000" is output as shown by DS1 in the figure, for example, when data of columns of the normal region a1 is specified, "001001000" is output as shown by DS2 in the figure, for example, when a region of portions less than columns is specified.

Fig. 4 is a block diagram showing the structure of the fixed value output circuit 28 and input/output of data. The fixed value output circuit 28 is constituted by a function switching block 31, a data switching block 32, and an address decoder 33.

The function switching block 31 switches the output functions so as to output any of the output data from the data switching block 32 and the data read from the memory area 10 via the memory cell IF 27, based on the function validation signal FES supplied from the test mode control section 23, for example, when the function validation signal FES is invalid, the function switching block 31 outputs the data read from the memory area 10 via the memory cell IF 27, and further , when the function validation signal FES is valid, the function switching block 31 outputs a fixed value as the data on the data switching block 32 side.

The data switching block 32 outputs a fixed value "0" or "1" to the function switching block 31 according to switching by the address decoder 33.

The address decoder 33 switches the data switching block 32 based on the determination result (whether the access destination is the normal area a1 or the redundant area a 2) by the redundant area use determining section 25. Specifically, the switching of the data switching block 32 is performed in such a manner that "0" is output in the case where the access destination is the normal area a1 and "1" is output in the case of the redundant area a 2.

Thus, when the fixed value output function of the fixed value output circuit 28 is set to be active, "0" is output at the time of read access to the normal area a1 and "1" is output at the time of read access to the redundant area a2, in other , when the fixed value output function of the fixed value output circuit 28 is set to be inactive, access to the memory area 10 is performed and data stored in the memory cell is read out, that is, the fixed value output circuit 28 outputs a data sequence consisting of "0" and "1" when the 1 st output mode is set (fixed value output is active) and outputs data actually stored in the memory area 10 when the 2 nd output mode is set (fixed value output is inactive).

Next, the processing operation of the data acquisition process performed by the semiconductor memory device 100 of the present embodiment will be described with reference to the flowchart of fig. 5.

First, a test mode control command including a command to validate the fixed value output function of the fixed value output circuit 28 is issued from the outside of the semiconductor memory device 100 (for example, a DRAM controller). The semiconductor memory device 100 receives the test mode control command via the user IF 21 (step 101).

The command/address analysis unit 22 analyzes the command and supplies the analyzed command to the test mode control unit 23. The test mode control unit 23 switches the functional block 31 so that the functional block 31 outputs data on the data switching block 32 side. Thus, the semiconductor memory device 100 is in a state of always outputting "0" at the time of read access to the normal area a1 and always outputting "1" at the time of read access to the redundant area a2, regardless of the content of data held by the memory cells.

Next, the semiconductor memory device 100 receives a read command (read command) via the user IF 21 (step 102). the fixed value output circuit 28 outputs a distribution pattern that appears when "0" is written to the normal area a1 of the memory area 10 and "1" is written to the redundant area a 2. when an address that is desired to be output from the read command (read command) is specified, a data sequence extracted based on the address specified by the distribution pattern that appears when "0" is written to the normal area a1 and "1" is written to the redundant area a2 of the memory area 10 is output.

The semiconductor memory device 100 determines whether or not reading of the data sequence is completed (step 103). When it is determined that the reading is not completed (NO in step 103), the process returns to step 102 to wait for the reception of the read command again.

When the reading of the data sequence is completed (yes in step 103), a command to disable the function of the fixed value output circuit 28 is issued from the outside of the semiconductor memory device 100 (for example, a DRAM controller) in order to return the semiconductor memory device 100 to a normal use state. The semiconductor memory device 100 receives the command via the user IF 21 (step 104).

The command/address analysis unit 22 analyzes the command and supplies the analyzed command to the test mode control unit 23. The test mode control unit 23 switches the functional block 31 so that the functional block 31 outputs data on the memory cell IF 27 side. Thus, the semiconductor memory device 100 is in a state of outputting the content of the data held in the memory cell.

As described above, the semiconductor memory device 100 of the present embodiment includes the fixed value output circuit 28, and outputs the data sequence including 2-valued data showing the arrangement relationship between the normal block and the defective block. With this configuration, it is possible to obtain the same data sequence in a short time as in the case of writing "0" into the memory cell of the normal area a1 and "1" into the memory cell of the redundant area a2 without actually writing data into the memory area.

Further, since the data sequence can be output without writing for outputting the data sequence and while maintaining the stored data in the memory area 10, the data sequence can be obtained without affecting the use state of the memory area 10.

[ example 2]

Next, example 2 of the present invention will be explained. Fig. 6 is a block diagram showing the structure of the semiconductor memory 200 of the present embodiment. The semiconductor memory 200 of the present embodiment is different from the semiconductor memory device 100 of embodiment 1 in that it has a fixed value auto-write circuit 40 instead of the fixed value output circuit 28.

The fixed value automatic write circuit 40 is provided in the test mode control section 23. The fixed value automatic write circuit 40 has a function of automatically writing "0" to all of the normal area a1 and "1" to all of the redundant area a2 of the memory area 10.

Fig. 7 is a block diagram showing the structure of the fixed value automatic write circuit 40 and the input/output of data. The fixed value automatic write circuit 40 includes a counter 41, an address generation section 42, a control signal generation section 43, an address decoder 44, and a data switching block 45.

The counter 41 starts counting in response to a command supplied from a DRAM controller or the like outside the semiconductor memory device 200 via the command/address analysis unit 22. The counter 41 counts up the number of write times of the entire area of the memory area 10.

The address generation unit 42 generates an address by incrementing the count of the counter 41. The control signal generator 43 generates a control signal.

The address decoder 44 determines which of the normal area a1 and the redundant area a2 the address generated by the address generation section 42 shows, and supplies the result thereof to the data switching block 45.

The data switching block 45 determines "0" as data to be written into the memory area 10 when the determination result by the address decoder 44 is the normal area a1, and determines "1" as data to be written into the memory area 10 when the determination result is the redundant area a 2.

The fixed value automatic write circuit 40 receives an issue of a command for writing all of the normal/redundant areas from a DRAM controller or the like outside the semiconductor memory device 200 and performs write processing. That is, the semiconductor memory device 200 generates an automatic write start signal in response to reception of all write commands via the user IF 21, and supplies the automatic write start signal to the test mode control unit 23. The fixed value auto-write circuit 40 writes "0" to all of the normal area a1 and "1" to all of the redundant area a2 in response to the auto-write signal.

When a read command is received from a DRAM controller or the like outside the semiconductor memory device 200 via the user IF 21, the semiconductor memory device 200 outputs a data sequence made up of data of "0" and "1" written to the memory area 10 in accordance therewith.

As described above, in the semiconductor memory device 200 of the present embodiment, the fixed value automatic write circuit 40 provided in the test mode control section 23 performs writing of "0" into the normal area a1 of the memory area and writing of "1" into the redundant area a 2. With this configuration, writing can be performed in a shorter time than in the case where writing is performed from the outside of the semiconductor memory device 200.

For example, in the case of 1Gbit DRAM with a data rate of 1600Mbps at maximum, 1024Mbit/1600Mbps =640ms is required at the lowest among all writes in the normal area a 1. Further, a processing time is required for the DRAM controller to issue a repeat of 800 ten thousand or more commands. In contrast, according to the semiconductor memory device 200 of the present embodiment, since the command is issued 1 time from the DRAM controller, the processing time is significantly shortened.

The present invention is not limited to the above embodiments. For example, in the above-described embodiment 2, a case has been described in which a command for writing all of the normal/redundant areas is issued from the DRAM controller, and the fixed value automatic write circuit 40 writes data of "0" or "1" in the normal area a1 and the redundant area a2 in accordance with the command. However, the timing of writing data is not limited to this. For example, the writing process can be automatically performed after the reset release without a command from the DRAM controller.

Description of reference numerals

100 semiconductor memory device

10 memory area

General area of A1

A2 redundant area

11 fuse

12 control logic circuit

21 subscriber IF

22 command/address analysis unit

23 test mode control part

24 read/write control section

25 redundant area use judging part

26 fuse interface

27 memory cell IF

28 fixed value output circuit

31 function switching block

32 data switching block

33 address decoder

40 fixed value automatic write circuit

41 counter

42 address generating part

43 control signal generating part

44 address decoder

45 data switch block.