The inventive concepts relate to a semiconductor memory device, and more particularly, to a semiconductor memory device and/or system having redundancy cells, and/or methods associated therewith.
A consistent increase in the size of semiconductor memories has caused a gradual increase in a defective cell occurrence probability. According to the existing methods of repairing such a defective cell, when a defective cell occurrence probability increases, redundancy resources are limited due to the limitation in flexibility of a repair unit. In addition, if a group unit of redundancy cells replaced due to an increase in memory density is constant, the number of replaced redundancy cells increases, causing an increase in a chip size.
At least one embodiment relates to a memory device.
In one embodiment, the memory device includes a memory cell array, a data line selection circuit and selection control logic. The memory cell array has at least a first memory cell group and a redundancy memory cell group. The first memory cell group includes a plurality of first memory cells associated with a first data line, and the redundancy memory cell group includes a plurality of redundancy memory cells associated with a redundancy data line. The selection control logic is configured to detect if a defective memory cell in the first memory cell group is being accessed, and is configured to control the data line selection circuit to replace access via the first data line with access via the redundancy data line such that a detected defective memory cell in the first memory cell group is replaced with one of the plurality of redundancy memory cells. The selection control logic includes a storage device configured to store address information for defective memory cells. The address information includes row address information and column address information identifying rows and columns in the first memory cell group including defective memory cells. The selection control logic also includes control signal generation logic configured to generate a control signal for controlling the data line selection circuit based on the address information and a received address. The received address identifies at least one memory cell in the cell array being accessed.
In one embodiment, the control signal generation logic includes a comparator configured to compare the address information and the received address, and the control signal generation logic is configured to generate the control signal based on the comparison.
In one embodiment, the comparator includes a row comparator and a column comparator. The row comparator is configured to compare the row address information with a received row address represented by the received address. The column comparator is configured to compare the column address information with a received column address represented by the received address.
In one embodiment, the row comparator includes a row address memory unit. The row address memory unit is configured to receive the row address information from the storage device and store the row address information.
In one embodiment, the column comparator includes a column address memory unit. The column address memory unit is configured to receive the column address information from the storage device and store the column address information.
In one embodiment, the storage device is a non-volatile memory device, and the row and column address memory units are volatile memory devices. For example, the volatile memory devices may be content addressable memories.
In one embodiment, the comparator is configured to generate a selection signal based on the comparison. The selection signal indicates whether a defective memory cell exists and identifies a memory group including the defective memory cell, and the control signal generation logic is configured to generate the control signal based on the selection signal.
In one embodiment, the control signal generation logic further includes a code generator configured to generate the control signal based on the selection signal. For example, the control signal includes a bit for controlling operation of each selection unit in the data line selection circuit.
In one embodiment, the memory cell array includes first to nth memory cell groups, where n is greater than or equal to 2. Each of the first to nth memory cell groups is associated with first to nth data lines. Here, the data line selection circuit is configured to provide data paths between (i) the redundancy data line and the first to nth data lines and (ii) first to nth input/output nodes.
In one embodiment, the data line selection circuit includes first to nth selection units. Each of the first to nth selection units is associated with a respective one of the first to nth input/output nodes. Each of the first to nth selection units has a first node associated with a respective one of the first-nth data lines and has a second node associated with one of the redundancy data line and the first to nth data lines. Each of the first to nth selection units is configured to provide a data path from one of the first and second nodes to the associated one of first to nth input/output nodes based on the control signal. In one embodiment, each of the first to nth selection units includes a multiplexer. In one embodiment, each of the first to nth input/output nodes is a DQ pad. In one embodiment, the control signal generation logic includes a comparator configured to compare the address information and the received address, and the control signal generation logic is configured to generate the control signal based on the comparison.
In one embodiment, the comparator is configured to generate a selection signal based on the comparison. The selection signal indicates whether a defective memory cell exists and identifies a one of the first to nth memory groups including the defective memory cell, and the control signal generation logic is configured to generate the control signal based on the selection signal.
In one embodiment, the control signal generation logic further includes a code generator configured to generate the control signal based on the selection signal. The control signal includes a bit associated with each of the first to nth selection units, each bit of the control signal indicating which of the first and second nodes of the associated one of the first to nth selection units to couple to the associated one of the first to nth input/output nodes.
In one embodiment, the second node of the first to (n−1)th selection units is associated with the data line for the second to nth memory cell groups; the second node of the nth selection unit is associated with the redundancy data line; and the control signal generation logic is configured to generate a control signal such that if a detected defective memory cell is in the mth memory cell group, the first to mth selection units provide a data path including the second node, and the (m+1)th to nth selection units provide a data path including the first node.
In one embodiment, the control signal generation logic is configured to generate the control signal such that the data paths provided by the data line selection circuit do not include a one of the first to nth data lines associated with a one of the first to nth memory cell groups including a detected defective memory cell.
In one embodiment, at least one of the first to nth data lines is connected to a sense amplifier arranged in a lengthwise direction of the memory cell array, and at least one of the first to nth data lines is connected to a sense amplifier arranged in a widthwise direction of the memory cell array.
In one embodiment, the storage device is configured to store address information such that one of the first to nth memory cell groups including a defective memory cell is replaced by the redundancy memory cell group.
In one embodiment, the storage device is configured to store address information such that a defective memory cell is replaced by a single redundancy memory cell. In one embodiment, the selection control logic is configured to not replace non-defective memory cells in a column including the defective memory cell such that the non-defective memory cells remain accessible.
In one embodiment, the storage device is configured to store address information such that a column of memory cells including a defective memory cell are replaced by a column of redundancy memory cells.
In one embodiment, the storage device is configured to store address information such that only a portion of a column of memory cells including a defective memory cell are replaced by a portion of a column of redundancy memory cells. In one embodiment, the selection control logic is configured to not replace non-defective memory cells in a remaining portion of the column including the defective memory cell such that the non-defective memory cells in the remaining portion remain accessible.
In one embodiment, the first memory cell group includes at least one column of internal redundancy memory cells for replacing defective memory cells in the first memory cell group.
In one embodiment, the memory device includes a memory cell array, a data line selection circuit and selection control logic. The memory cell array has at least a first memory cell group and a redundancy memory cell group. The first memory cell group includes a plurality of first memory cells arranged in columns and rows, and the plurality of first memory cells are associated with a first data line. The redundancy memory cell group includes a plurality of redundancy memory cells arranged in columns and rows, and the plurality of redundancy memory cells are associated with a redundancy data line. The selection control logic is configured to detect if a defective memory cell in the first memory group is being accessed, and is configured to control the data line selection circuit to replace access via the first data line with access via the redundancy data line such that a portion of a column of the plurality of first memory cells including the detected defective memory cell in the first group is replaced with a portion of a column of the plurality of redundancy memory cells.
In one embodiment, the portion of the column of the plurality of first memory cells includes a non-defective memory cell. In one embodiment, the selection control logic is configured to not replace non-defective memory cells in a remaining portion of the column including the defective memory cell such that the non-defective memory cells in the remaining portion remain accessible.
In one embodiment, the memory device includes a memory cell array, a data line selection circuit and selection control logic. The memory cell array has first to nth memory cell groups and a redundancy memory cell group, where n is greater than or equal to 2. Each of the first to nth memory cell groups is associated with first to nth data lines. The first to nth memory cell groups include first to nth pluralities of memory cells arranged in columns and rows, and the redundancy memory cell group includes a plurality of redundancy memory cells arranged in columns and rows. The plurality of redundancy memory cells are associated with a redundancy data line. The selection control logic is configured to detect if a defective memory cell in one of the first to nth memory groups is being accessed, and is configured to control the data line selection circuit to replace access via one of the first to nth data lines with access via the redundancy data line such that the one of the first to nth memory cells groups including the detected defective memory cell is replaced with the redundancy memory cell group.
In one embodiment, the memory device includes a memory cell array, a data line selection circuit and selection control logic. The memory cell array has at least a first memory cell group and a redundancy memory cell group. The first memory cell group includes a plurality of first memory cells arranged in columns and rows, and the plurality of first memory cells are associated with a first data line. The redundancy memory cell group includes a plurality of redundancy memory cells arranged in columns and rows, and the plurality of redundancy memory cells are associated with a redundancy data line. The selection control logic is configured to detect if a defective memory cell in the first memory group is being accessed, and is configured to control the data line selection circuit to replace access via the first data line with access via the redundancy data line such that a detected defective memory cell in the first group is replaced with one of the plurality of redundancy memory cells according to a desired replacement scheme. The desired replacement scheme is a programmable feature of the selection control logic.
In one embodiment, the desired replacement scheme causes the selection control logic to replace one of the first to nth memory cell groups including a defective memory cell with the redundancy memory cell group.
In one embodiment, the desired replacement scheme causes the selection control logic to replace a defective memory cell with a single redundancy memory cell.
In one embodiment, the desired replacement scheme causes the selection control logic to not replace non-defective memory cells in a column including the defective memory cell such that the non-defective memory cells remain accessible.
In one embodiment, the desired replacement scheme causes the selection control logic to replace a column of memory cells including a defective memory cell with a column of redundancy memory cells.
In one embodiment, the desired replacement scheme causes the selection control logic to replace only a portion of a column of memory cells including a defective memory cell with a portion of a column of redundancy memory cells. In one embodiment, the desired replacement scheme causes the selection control logic to not replace non-defective memory cells in a remaining portion of the column including the defective memory cell such that the non-defective memory cells in the remaining portion remain accessible.
In one embodiment, the selection control logic includes a storage device configured to be programmed with address information for defective memory cells according to the desired replacement scheme. The address information includes row address information and column address information identifying rows and columns in the first to nth memory cell groups including defective memory cells. The control signal generation logic is configured to generate a control signal for controlling the data line selection circuit based on the address information and a received address. The received address identifies at least one memory cell in the cell array being accessed.
At least one embodiment relates to system such as a computer system, memory card, electronic device, wireless phone, etc. including the memory device according to one of the example embodiments.
At least one embodiment relates to a method of replacing defective memory cells.
In one embodiment, the method is applied to a memory cell array having at least a first memory cell group and a redundancy memory cell group, the first memory cell group including a plurality of first memory cells associated with a first data line, and the redundancy memory cell group including a plurality of redundancy memory cells associated with a redundancy data line. The method includes detecting if a defective memory cell in the first memory cell group is being accessed, and controlling a data line selection circuit to replace access via the first data line with access via the redundancy data line such that a detected defective memory cell in the first memory cell group is replaced with one of the plurality of redundancy memory cells. The controlling includes storing, in a storage device, address information for defective memory cells. The address information includes row address information and column address information identifying rows and columns in the first memory cell group including defective memory cells. The controlling also includes generating a control signal for controlling the data line selection circuit based on the address information and a received address. The received address identifies at least one memory cell in the cell array being accessed.
In another embodiment, the method applies to a memory cell array having at least a first memory cell group and a redundancy memory cell group, the first memory cell group including a plurality of first memory cells arranged in columns and rows, and the plurality of first memory cells being associated with a first data line, and the redundancy memory cell group including a plurality of redundancy memory cells arranged in columns and rows, and the plurality of redundancy memory cells being associated with a redundancy data line. The method includes detecting if a defective memory cell in the first memory group is being accessed, and controlling, by a selection control logic, a data line selection circuit to replace access via the first data line with access via the redundancy data line such that a portion of a column of the plurality of first memory cells including the detected defective memory cell in the first group is replaced with a portion of a column of the plurality of redundancy memory cells.
In one embodiment, the method applies to a memory cell array having first to nth memory cell groups and a redundancy memory cell group, where n is greater than or equal to 2. Each of the first to nth memory cell groups is associated with first to nth data lines. The first to nth memory cell groups includes first to nth pluralities of memory cells arranged in columns and rows, and the redundancy memory cell group includes a plurality of redundancy memory cells arranged in columns and rows. The plurality of redundancy memory cells is associated with a redundancy data line. The method includes detecting if a defective memory cell in one of the first to nth memory groups is being accessed, and controlling, by a selection control logic, a data line selection circuit to replace access via the first data line with access via the redundancy data line such that the one of the first to nth memory cells groups including the detected defective memory cell is replaced with the redundancy memory cell group.
In one embodiment, the method applies to a memory cell array having at least a first memory cell group and a redundancy memory cell group, the first memory cell group including a plurality of first memory cells arranged in columns and rows, and the plurality of first memory cells being associated with a first data line, the redundancy memory cell group including a plurality of redundancy memory cells arranged in columns and rows, and the plurality of redundancy memory cells being associated with a redundancy data line. The method includes detecting if a defective memory cell in the first memory group is being accessed, and controlling, by a selection control logic, a data line selection circuit to replace access via the first data line with access via the redundancy data line such that a detected defective memory cell in the first group is replaced with one of the plurality of redundancy memory cells according to a desired replacement scheme. The desired replacement scheme is a programmable feature of the selection control logic.
Exemplary embodiments of the inventive concepts will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings in which:
Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments may be embodied in many different forms and should not be construed as being limited to the example embodiments set forth herein. Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail to avoid the unclear interpretation of the example embodiments. Throughout the specification, like reference numerals in the drawings denote like elements.
It will be understood that when an element or layer is referred to as being “on”, “connected to” or “coupled to” another element or layer, it may be directly on, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Referring to
The semiconductor memory device 100 may be a dynamic random access memory (DRAM) device. However, the semiconductor memory device 100 is not limited thereto and may include a plurality of memories of different types, such as a random-access memory (RAM), a read only memory (ROM), a synchronous dynamic random access memory (SDRAM), a NAND flash memory, a NOR flash memory, a Phase-Change Random Access Memory (PRAM), a Magnetic Random Access memory (MRAM), a Resistive Random Access Memory (ReRAM), and a Ferroelectric Random Access Memory (FRAM), which may be provided as internal semiconductor integrated circuits in computers and other electronic devices.
The memory cell array 110 may include a plurality of memory cell groups. For example, the memory cell array 110 may include a first memory cell group 111, a second memory cell group 112, a third memory cell group 113, and a fourth memory cell group 114. The memory cell array 110 may further include a redundancy cell group 115.
A fault may occur in at least one of memory cells included in the first to fourth memory cell groups 111, 112, 113, and 114. In the specification, a defective cell may be referred to as a single bit or a weak cell. A weak cell in the first to fourth memory cell groups 111, 112, 113, and 114 may be replaced with a redundancy cell included in the redundancy cell group 115 by the replacement control architecture 150.
Each of the first to fourth memory cell groups 111, 112, 113, and 114 may be defined in various ways. For example, the memory cell array 110 may include a plurality of memory banks or memory blocks, wherein each of the first to fourth memory cell groups 111, 112, 113, and 114 may be defined as a memory bank or a memory block. Alternatively, each of the first to fourth memory cell groups 111, 112, 113, and 114 may be defined as an area for inputting and outputting data through a different data line. In detail, memory cells included in each of the first to fourth memory cell groups 111, 112, 113, and 114 may be connected to global data lines through bit lines (not shown) and local data lines (not shown). For example, data in memory cells included in the first memory cell group 111 may be transferred through first to fourth global data lines GDL[1,1], GDL[1,2], GDL[1,3], and GDL[1,4] in a first group. Likewise, data in memory cells included in the second memory cell group 112 may be transferred through first to fourth global data lines GDL[2,1], GDL[2,2], GDL[2,3], and GDL[2,4] in a second group, data in memory cells included in the third memory cell group 113 may be transferred through first to fourth global data lines GDL[3,1], GDL[3,2], GDL[3,3], and GDL[3,4] in a third group, and data in memory cells included in the fourth memory cell group 114 may be transferred through first to fourth global data lines GDL[4,1], GDL[4,2], GDL[4,3], and GDL[4,4] in a fourth group.
Data in redundancy cells included in the redundancy cell group 115 may also be transferred through bit lines (e.g., redundancy bit lines (not shown)), local data lines (e.g., redundancy data lines (not shown)), and global data lines (e.g., first to fourth redundancy global data lines RGDL[1], RGDL[2], RGDL[3], and RGDL[4]). The same row and corresponding column as one of the accessed memory cell groups is accessed via the redundancy global bit lines RGBL.
Referring to
Data may be written or read by enabling the first to pth word lines WL[1] to WL[p] and the first to qth bit lines BL[1] to BL[q]. Data applied to the first to qth bit lines BL[1] to BL[q] is transferred to first to qth local data lines LDL[1], LDL[2], LDL[3] . . . , LDL[q] in response to a column selection operation, and data amplified by first to qth local sense amplifiers LSA[1], LSA[2], LSA[3] . . . , LSA[q] is transferred to first to qth global data lines GDL[1], GDL[2], GDL[3] . . . , GDL[q].
Data lines for transferring data in the redundancy cell group 115 may also have the local data line and global data line structure. Referring back to
For example, as shown in
According to another embodiment of the inventive concepts, in the semiconductor memory device 100, an internal redundancy memory cell group for internally performing repair in each of the first to fourth memory cell groups 111, 112, 113, and 114 may be included in the first to fourth memory cell groups 111, 112, 113, and 114, and the separate redundancy memory cell group 115 may be arranged for repair with respect to the first to fourth memory cell groups 111, 112, 113, and 114. For example, as shown in
Similarly, as shown in
The repair operations of a weak cell that are shown in
With respect to the above discussed replacement schemes, it will be understood that the example embodiments are not limited to a memory cell array having four memory cell groups as shown in
Referring to
The redundancy memory cell group 315 may be connected to at least one redundancy global data line, and for example,
Since the redundancy memory cell group 315 has a smaller area than the other memory cell groups 311 to 314, an area for arranging the LSAs may be limited. Therefore, at least one vertical LSA (V-LSA) 317 may be further arranged in a width-wise direction of the memory cell array 310 (e.g., a vertical direction in
Referring to
The memory cell array 210 may be configured in the same or similar manner to the memory cell array 110 shown in
The address controller 240 receives an address Addr from the outside and outputs a row address RA and a column address CA based on the received address Addr. The row decoder 230 decodes the row address RA to activate a word line of the memory cell array 210. The column decoder 220 decodes the column address CA to connect data lines of the memory cell groups 211 and the redundancy memory cell group 215 to respective global data lines and redundancy global data lines.
The replacement control architecture 250 includes a data line selection circuit 260 and selection control logic 270. The data line selection circuit 260 provides data paths between (1) global data lines and redundancy global data lines and (2) input/output nodes of the memory device. The input/output nodes DQ may be well-known input/output pads DQ0 . . . DQm as shown in
The selection control logic 270 includes a non-volatile memory 272 and control signal generation logic 280. The non-volatile memory 272 stores address information for defective cells in the memory array 210 and mode information. The mode information indicates the operating mode of the memory device 200 such as the data width (X8, X4 even, X4 odd, etc.). The address information includes row address information and column address information identifying rows and columns in the memory cell groups 211 including defective memory cells. For example, for single defective cell replacement as shown in
As shown in
The column comparator 288 includes a column address content addressable memory CAM_C, which may be one or more registers. During, for example start-up of the memory device, the non-volatile memory 272 loads the column address information FAIL_CA into the column address content addressable memory CAM_C. The non-volatile memory 272 also loads the mode information into the column address content addressable memory CAM_C. If the row comparator 286 makes a positive determination, the column comparator 288 compares the column address from the address controller 240 with the column address information to determine whether the addressed column from the address controller 240 is included in the column address information. If a positive determination is made, the column comparator 288 generates a selection signal SEL associated therewith. The selection signal and its generation will be described in greater detail below after the description of the data line selection circuit 260. The control code generator 284 generates the control signal or code based on the selection signal. The control code generator 284 will be described in greater detail below after the description of the data line selection circuit 260.
The data line selection circuit 260 will now be described in greater detail with respect to
Referring to
The semiconductor memory device 200 performs repair on the basis of a data line selection operation in the data line selection circuit 260. The data line selection circuit 260 is connected to global data lines of the first to eighth memory cell groups 211_1 to 211_8 and redundancy global data lines of the redundancy memory cell group 215 and inputs and outputs via first to eighth input/output nodes DQ0 to DQ7. For example, if data to be accessed is stored in normal cells, the data line selection circuit 260 normally outputs data in the first to eighth memory cell groups 211_1 to 211_8, otherwise if data in a defective cell is accessed, the data line selection circuit 260 controls data in the redundancy memory cell group 215 to be output instead of the data in the defective cell.
The data line selection operation described above may be performed on the basis of the control signal CS, which will be described in greater detail below.
An example of the data line selection operation in the semiconductor memory device 200 will now be described. It is assumed in the description of the current embodiment that a selection operation of global data lines is performed.
If data stored in normal cells is accessed, data in the first to eighth memory cell groups 211_1 to 211_8 is output to first to eighth input/output nodes DQ0 to DQ7 through the data line selection circuit 260. Otherwise, if a defective cell in, for example, the third memory cell group 211_3 is accessed, the data line selection circuit 260 performs a selection operation of the global data lines and the redundancy global data lines, for example, outputs data in the first and second memory cell groups 211_1 and 211_2 at the first and second input/output nodes DQ0 and DQ1 and outputs data in the fourth to eighth memory cell group 211_4 to 211_8 and the redundancy memory cell group 215 at the third to eighth input/output nodes DQ2 to DQ7, respectively.
A shifting operation of the global data lines is performed according to a selection operation of the first to eighth selection units 430_1 to 430_8. For example, in a normal operation, data transferred through the global data lines of the fourth memory cell group 211_4 is output at the fourth input/output node DQ3 through the fourth selection unit 430_4. During a data line shifting operation for repairing a defective memory cell, data transferred through the global data lines of the fourth memory cell group 211_4 is output at the third input/output node DQ2 through the third selection unit 430_3 assuming the defective cell is not in the fourth memory cell group 211_4. In addition, a data output of a defective cell is blocked, and instead, data in the redundancy memory cell group 215 is output at the eighth input/output node DQ7 through the redundancy global data lines and the eighth selection unit 430_8. On the basis of the shifting operation, even if any cell in any one of the first to eighth selection units 430_1 to 430_8 is defective, repair may be performed by the single redundancy memory cell group 215.
The recent specifications of semiconductor memory devices require that input and output data is output through only specific input and output pins according to a separately set data width option. For example, in a case of a semiconductor memory device having 16 input and output pins, data is input and output through the 16 input and output pins if an X16 data width option (or X16 data width mode) is set, and data is input and output through only 8 input and output pins if an X8 data width option is set. Similarly, if an X4 data width option is set, data is input and output through only 4 input and output pins.
If the X8 data width option is set, a memory is selected by a desired (or, alternatively, a predetermined) number of row and column addresses, and for example, a memory may be selected in response to first to thirteenth row addresses RA01 to RA13 and first to tenth column addresses CA01 to CA10. Otherwise if the X16 data width option is set, the thirteenth row address RA13 is ignored (don't care), and accordingly, double data compared to the X8 option may be input and output. Otherwise if the X4 data width option is set, an eleventh column address CA11 is further used, and accordingly, half the amount of data compared to the X8 data width option may be input and output.
In the example shown in
Each of the first to fourth selection units 431 to 434 may be connected to at least two memory cell groups (including the redundancy memory cell group 215). For example, each of the first and second selection units 431 and 432 may be connected to global data lines of three memory cell groups, the third selection unit 433 may be connected to global data lines of two memory cell groups and the redundancy global data lines, and the fourth selection unit 434 may be connected to global data lines of one memory cell group and the redundancy global data lines. However, this is only illustrative, and each of the first to fourth selection units 431 to 434 may be implemented to have a same selection circuit structure.
As a simple example, when a defective cell in the third memory cell group 211_3 is accessed in an option for inputting and outputting first and third data at DQ0 and DQ2, data in the redundancy memory cell group 215 is provided as third data at DQ2 through the third selection unit 433, and data in the first memory cell group 211_1 is provided as first data at DQ0 through the first selection unit 431. In addition, when a defective cell in the second memory cell group 211_2 is accessed in an option for inputting and outputting second and fourth data at DQ1 and DQ3, data in the redundancy memory cell group 215 is provided as fourth data at DQ3 through the fourth selection unit 434, and data in the fourth memory cell group 2114 is provided as second data at DQ1 through the second selection unit 432.
In addition, in a case of an option for inputting and outputting first and fourth data at DQ0 and DQ3, a repair operation may be performed by performing a shifting operation using the same method as in the connection structure of
As shown in
In the structure of
Furthermore, it will be understood that the MUXs create data paths between a connection node and one of a plurality of selection nodes. In the example of
The control code generator 284, in the selection control logic 270, for controlling the first to eighth selection units 430_1 to 430_8 is also shown. As shown in
If an address Addr from the outside is not of a defective cell, the first to eighth selection units 430_1 to 430_8 normally output data without a shifting operation of data lines. Otherwise, if the address Addr from the outside is of a defective cell, data is blocked from being output through a data line connected to the defective cell by a shifting operation of data lines, and instead, the data is output through a data line connected to a redundancy cell.
The control code generator 284 may store information, as shown in
In addition,
The X4 bit and CA11 bit comprise the mode information received from the nonvolatile memory 272 by the column comparator 288. The column comparator 288 determines the MF bit and the F0, F1, and F2 bits based on whether a defective memory cell is detected. If the detection is positive, the MF bit is set to 1. Then, depending on the memory cell group including the defective memory cells, as indicated by the column address, the column comparator generates the F0, F1 and F2 bits to indicate the memory cell group as shown in
The code generator 284 maps the selection signal into a control code or control signal having a bit associated with each selection unit 430_1 to 430_8 of the data line selection circuit. In the table of
For example, when an address input for access is of a normal cell, the MF bit may be 0, and in this case, a data line shifting operation is not performed. Also, since no defective cell exists, the remaining bits of the selection signal SEL are “don't care”. Otherwise, when the input address is of a defective cell, a MF bit is set to 1, and in this case, a shifting operation of at least one data line is controlled according to a control code shown in
If a defective cell is detected in the fifth memory cell group 211_5, the selection units 430_1 to 430_5 corresponding to the first to fifth input/output nodes DQ0 to DQ4 may perform shifting of data lines to block data in the defective cell from being transferred through the data lines, and selection units 430_6 to 430_8 corresponding to the sixth to eighth input/output nodes DQ5 to DQ7 may normally output data without shifting data lines. Namely, the first selection unit 430_1 provides a data path from the redundancy global data line of the redundancy memory cell group 215 to the first input/output node DQ0, the second though fifth selection units 4302 to 430_5 provide data paths from global data lines of the first to fourth memory cell groups 211_1 to 211_4 to the second to fifth input/output nodes DQ1 to DQ4, respectively, and the sixth to eighth selection units 430_6 to 430_8 provide data paths from the global data lines of the sixth to eighth memory cell groups 211_6 to 211_8 to the sixth to eighth input/output nodes DQ5 to DQ7, respectively.
As shown in
The thermometer code described above is an example of a control code for controlling the data line selection circuit 260, and the data line selection circuit 260 may be controlled by another control code generation method or controlled by thermometer codes set as different values.
Still further, it will be appreciated, that instead of the F0, F1 and F2 bits, the selection signal may instead include the control signal or code. Namely, the column comparator 288 may directly generate the control signal as the selection signal. In this embodiment, the code generator is not necessary, and the selection signal is applied to the data line selection circuit 260.
As illustrated in
For example, when a memory cell connected to a fourth global data line of the fourth memory cell group 211_4 is a defective cell, data of the fourth memory cell group 211_4 may be output via first through third MUXes and fifth through eighth MUXes of the fourth selection unit 430_4. On the other hand, data of the redundancy memory cell group 215 may be output via a fourth MUX of the fourth selection unit 430_4. Moreover, as described above, switching operations of the third and fourth selection units 430_3 and 430_4 may be controlled according to control codes.
Referring to
The memory cell array 1510 may include a plurality of memory cell groups, namely, first through fourth memory cell groups 1511 through 1514. The memory cell array 1510 may further include a redundancy memory cell group 1515 for replacing defective cells generated in the first through fourth memory cell groups 1511 through 1514. The first through fourth selection units 1531 through 1534 may operate in the same or similar manner as the first through fourth selection units 430_1 through 430_8 of
Data may be input to and output to the first selection unit 1531 via the first buffer unit 1541. Similarly, data may be input to and output to the second through fourth selection units 1532 through 1534 via the second through fourth buffer units 1542 through 1544, respectively.
A semiconductor memory device 1600 of
According to the embodiment of
Although
A connection structure between global data lines and first to eighth selection units 531 to 538 in the semiconductor memory device 500 of
Each of the first to eighth selection units 531 to 538 may be connected to at least three global data lines. Exceptionally, the first selection unit 531 located at the edge is connected to the first global data line and twice to a redundancy global data line. According to the 3:1 MUX structure, the redundancy global data line may be connected to two selection nodes of the first selection unit 531.
Similarly, the second selection unit 532 is connected to the redundancy global data line and the first and second global data lines. In addition, the third selection unit 533 is connected to the first to third global data lines, . . . , the eighth selection unit 538 is connected to the sixth to eighth global data lines.
When the semiconductor memory device 500 operates in the X8 data width option, according to the switch arrangement pattern shown in
For example, when data in the first to eighth memory cell groups is accessed by the same column selection signal, in which a defective cell in the fifth memory cell group 515 is accessed, data in the redundancy memory cell group 521 and the first to fourth memory cell groups 511 to 514 is output as first to fifth data to DQ0 to DQ4. In addition, a data output from the fifth memory cell group 515 is blocked, and data in the sixth to eighth memory cell groups 516 to 518 is output as sixth to eighth data to DQ5 to DQ7.
When the semiconductor memory device 500 operates in the X4 data width option, only two switches from the right of a MUX included in each of the first to eighth selection units 531 to 538 may operate. When a defective cell is accessed, a data line shifting operation for repairing the defective cell is performed. In the case of
Examples of the data line shifting operation will now be described in detail with reference to
According to a switching operation of the first to eighth selection units 531 to 538, a shifting operation with respect to the redundancy global data line and the first to fourth global data lines is performed. For example, the first selection unit 531 selectively outputs data received through the redundancy global data line, and the second to fifth selection units 532 to 535 selectively output data received through the first to fourth global data lines.
In addition, a data output through the fifth global data line is blocked, and data received through the sixth to eighth global data lines is output as sixth to eighth data to DQ5 to DQ7 without a shifting operation. According to the example of
According to the X4 data width option, data is transmitted and received through four of the eight selection units. For example, data transferred through oddth global data lines may be output as first to fourth data to the first, third, fifth and seventh input/output nodes DQ0, DQ2, DQ4 and DQ6, also referred to as the first to fourth odd mode input/output nodes DQO0, DQO1, DQO2 and DQO3. In this case, for a memory access, an eleventh column address CA11 may be additionally used, and for example, the first, third, fifth, and seventh memory cell groups 511, 513, 515, and 517 may be accessed.
According to the example described above, a plurality of memory cell groups (e.g., the first to eighth memory cell groups) may be classified into an even area and an odd area, and a defective cell in the even area or the odd area may be repaired using a single redundancy cell. That is, on the basis of a shifting operation, a defective cell in any one of four memory cell groups may be repaired using a single redundancy global data line.
When a defective cell in the fifth memory cell group 515 of the odd area is accessed, a data line shifting operation is performed by a switching operation of the first, third, fifth, and seventh selection units 531, 533, 535, and 537. For example, data transferred through the redundancy global data line is output as first data to DQ0 by a switching operation of the first selection unit 531.
Since the first global data line is shifted in a group unit of two global data lines, data transferred through the first global data line is output as second data to DQ2 (DQO1) by a switching operation of the third selection unit 533. Similarly, data transferred through the third global data line is output as third data to DQ4 (DQO2) by a switching operation of the fifth selection unit 535. However, an output of data through the fifth global data line corresponding to the fifth memory cell group 515 is blocked, and data in the seventh memory cell group 517 is output as fourth data to DQ6 (DQO3) through the seventh global data line and the seventh selection unit 537.
According to the X4 data width option shown in
According to the X4 data width option, the memory cell groups in the even area (e.g., the second, fourth, sixth, and eighth memory cell groups 512, 514, 516, and 518) may be accessed (e.g., even operation mode), and accordingly, data transferred through the eventh global data lines may be output at the second, fourth, sixth and eighth input/output nodes DQ1, DQ3, DQ5 and DQ7, also referred to as the first to fourth even input/output nodes DQE0 to DQE3. The eleventh column address CA11 may be additionally used for memory access according to the X4 data width option, and in this case, a defective cell in the second, fourth, sixth, and eighth memory cell groups 512, 514, 516, and 518 may be flexibly repaired using a single redundancy global data line.
When a defective cell in the fourth memory cell group 514 is accessed, a data line shifting operation is performed by a switching operation of the second, fourth, sixth, and eighth selection units 532, 534, 536, and 538. For example, data transferred through the redundancy global data line is output as first data to DQE0 by a switching operation of the second selection unit 532. In addition, data transferred through the second global data line is output as second data to DQE1 by a switching operation of the fourth selection unit 534.
However, a data output through the fourth global data line is blocked, and data through the sixth and eighth global data lines is output as third and fourth data to DQE2 and DQE3 through the sixth and eighth selection units 536 and 538 without a shifting operation.
In the current embodiment, in both the X16 data width option and the X8 data width option, a defective cell in eight memory cell groups may be flexibly repaired through a single redundancy global data line. That is, when a defective cell occurs in a particular memory cell group, repair may be performed by performing a shifting operation in units of single global data line even though a defective cell occurs in any location of eight memory cell groups. In addition, in the X4 data width option, a defective cell in four memory cell groups may be flexibly repaired through a single redundancy global data line according to selected memory cell groups. For example, a defective cell in an even area or an odd area may be repaired through a single redundancy global data line.
As shown in
In the embodiment of
The first redundancy memory cell group 621 is used to repair a defective cell in four memory cell groups. For example, the first redundancy memory cell group 621 is used to repair a defective cell in the first to fourth memory cell groups, and the second redundancy memory cell group 622 is used to repair a defective cell in the fifth to eighth memory cell groups. As shown in
A defective cell in the fifth memory cell group 615 is repaired using the second redundancy memory cell group 622. Data transferred through the second redundancy global data line corresponding to the second redundancy memory cell group 622 is output as eighth data to DQ7 through the eighth selection unit 638. Similarly, a shifting operation of sixth to eighth global data lines is performed, and accordingly, data transferred through the sixth to eighth global data lines is output as fifth to seventh data to DQ4 to DQ6 through the fifth to seventh selection units 635 to 637.
Referring to
The global data lines arranged in the right of
A data line selection block 630 includes a plurality of selection units (not shown) that may perform the switching operations as described in
According to the embodiment described above, redundancy memory cell groups are arranged on both sides (e.g., the left and right) of one cell array, and repair may be performed using any one of the redundancy memory cell groups according to a location of a defective cell. In addition, two defective cells may be simultaneously accessed, and in this case, the two defective cells may be simultaneously repaired using the two redundancy memory cell groups. For example, a defective cell in memory cell groups of an even area may be repaired using any one of the two redundancy memory cell groups according to a location of a memory cell group including the defective cell.
As shown in
In the embodiment of
According to the embodiment of
As shown in
A shifting operation between global data lines corresponding to memory cell groups in the odd area is performed on the basis of a switching operation of the selection units 731 to 738, and accordingly, the defective cell in the fifth memory cell group 715 is repaired. For example, data transferred through a first global data line is output as third data to DQ2 through the third selection unit 733, and data transferred through a third global data line is output as fifth data to DQ4 through the fifth selection unit 735. An output of data transferred through a fifth global data line connected to the defective cell is blocked, and data transferred through a seventh global data line is output as seventh data to DQ6 through the seventh selection unit 737.
A shifting operation of global data lines corresponding to memory cell groups in the even area does not have to be performed, and accordingly, data transferred through second, fourth, sixth, and eighth global data lines corresponding to second, fourth, sixth, and eighth memory cell groups may be output through the second, fourth, sixth, and eighth selection units 732, 734, 736, and 738.
As shown in
Access to the memory cell groups belonging to the even area is not performed, and accordingly, the selection units corresponding to the even area (e.g., the second, fourth, sixth, and eighth selection units 732, 734, 736, and 738) may maintain a switching connection state of the corresponding global data lines (e.g., the second, fourth, sixth, and eighth global data lines) or may block connections thereof.
As shown in
As shown in
Although repair of the even or odd area is performed using a single redundancy memory cell group on the basis of a switching operation of the even/odd selection unit 740 in the previous embodiment, according to the current embodiment, repair of any one memory cell group belonging to one of the even and odd areas is performed using the first redundancy memory cell group 821, and repair of any one memory cell group belonging to the other one area is performed using the second redundancy memory cell group 822. Accordingly, as shown in
A first redundancy global data line corresponding to the first redundancy memory cell group 821 is connected to the first selection unit 831, and a first global data line corresponding to the first memory cell group 811 is commonly connected to the first and third selection units 831 and 833. In addition, a second redundancy global data line corresponding to the second redundancy memory cell group 822 is connected to the fourth selection unit 834, and a fourth global data line corresponding to the fourth memory cell group 814 is commonly connected to the second and fourth selection units 832 and 834. Operations of the semiconductor memory device 800 of
As shown in
A defective cell in the fifth memory cell group 815 belonging to the odd area is repaired using the first redundancy memory cell group 821. To do so, a data line shifting operation is performed, and as shown in
A defective cell in the sixth memory cell group 816 belonging to the even area is repaired using the second redundancy memory cell group 822. To do so, a data line shifting operation is performed, and as shown in
As shown in
As shown in
According to the embodiments described above, even though a semiconductor memory device operates using various options, such as the X16, X8, and X4 data width options, defective cells may be repaired, and a defective cell in a plurality of memory cell groups may be repaired using a single redundancy memory cell group. In addition, by arranging at least two redundancy memory cell groups per cell array including a plurality of memory cell groups, even when two or more defective cells are simultaneously accessed, the defective cells may be simultaneously repaired. For example, the plurality of memory cell groups may be classified into a plurality of areas, such as even and odd areas, and repair may be performed using a separate redundancy memory cell group in each area.
Each of the one or more cell arrays 910_1 and 910_2 may include a plurality of memory cell groups MCGs and a redundancy memory cell group RMCG. For example, a first cell array 910_1 may include a plurality of memory cell groups 911 and a first redundancy memory cell group 921 corresponding to the plurality of memory cell groups 911, and a second cell array 910_2 may include a plurality of memory cell groups 912 and a second redundancy memory cell group 922 corresponding to the plurality of memory cell groups 912. When eight memory cell groups are arranged in each of the first and second cell arrays 910_1 and 910_2, the eight memory cell groups in the first cell array 910_1 are connected to first to eighth global data lines GDL11 to GDL18, respectively.
Repair is performed on the basis of a data line selection operation of the data line selection block 930. The data line selection block 930 is connected to a plurality of global data lines GDL11 to GDL18 and GDL21 to GDL28 connected to the first and second cell arrays 910_1 and 910_2, respectively, and blocks data in a defective cell from being output and controls data in a redundancy cell to be output instead by a data line selection operation. When a data width option is set to X8, the data line selection block 930 outputs first to eighth data DQ0 to DQ7 of which repair has been performed.
According to the current embodiment, the data line selection block 930 performs a selection operation of global data lines corresponding to memory cell groups without separately having redundancy global data lines corresponding to the first and second redundancy memory cell groups 921 and 922. In addition, the first redundancy memory cell group 921 may be used to repair a defective cell in the second cell array 910_2, and the second redundancy memory cell group 922 may be used to repair a defective cell in the first cell array 910_1. For example, when a defective cell occurs in the first cell array 910_1, data obtained by accessing the second redundancy memory cell group 922 is transferred to any one global data line in the second cell array 910_2 (e.g., the ninth global data line GDL21) according to a column selection operation, and the data line selection block 930 blocks data in the defective cell from being output by performing a data line selection operation and outputs the data in the second redundancy memory cell group 922 instead. When a defective cell occurs in a third memory cell group of the first cell array 910_1, the data line selection block 930 blocks data transferred through the third global data line GDL13 from being output and outputs data transferred through the ninth global data line GDL21 instead.
According to the embodiment of
As shown in
As described above, a defective cell in the first cell array 910_1 may be repaired using the second redundancy memory cell group 922 in the second cell array 910_2, and data in the second redundancy memory cell group 922 may be transferred through a global data line corresponding to the second cell array 910_2 on the basis of a column selection operation. For example, the data in the second redundancy memory cell group 922 is transferred through the ninth global data line GDL21 that is connected to the eighth selection unit 938 corresponding to the first cell array 910_1. The reverse of this operation, where the first redundancy memory cell group 921 repairs a defect in the second cell array 910_2 via the selection unit 939 may also be performed.
The row decoder 940 simultaneously enables the word lines in the first and second cell arrays 910_1 and 910_2 in response to the row address RA. Accordingly, memory cells (e.g., normal memory cells) in any one of the first and second cell arrays 910_1 and 910_2 and redundancy cells in the other one of the first and second cell arrays 910_1 and 910_2 may be simultaneously selected.
Data in the normal memory cells and data in the redundancy cells may be transferred through data lines by a column selection operation according to the column address CA. For example, the column address CA may be provided to the first column decoder 951 corresponding to the first cell array 910_1 and the second redundancy column decoder 954 corresponding to the second redundancy memory cell group 922. As described above, according to enabling of a redundancy column selection line, data in redundancy cells may be transferred through a global data line. For example, data in the second redundancy memory cell group 922 may be transferred through the ninth global data line GDL21. In addition, whether the redundancy column selection line is enabled may be controlled by the column address matching operation in the embodiment described above.
Similarly, a redundancy memory cell group 922 includes a plurality of redundancy bit lines RBLs connected to redundancy cells therein. A redundancy column selection area 922_1 for connecting the redundancy memory cell group 922 to the global data line GDL21 is further included, and data in the redundancy cells is transferred through the global data line GDL21 on the basis of a column selection operation of the redundancy column selection area 922_1.
A timing register 1102 may be enabled when a chip select signal CS changes from a disable level (e.g., logic high) to an enable level (e.g., logic low). The timing register 1102 may receive command signals, such as a clock signal CLK. A clock enable signal CKE, a chip select bar signal
Some of the internal command signals generated by the timing register 1102 are stored in a programming register 1104. For example, latency information, burst length information, and so forth that are related to a data output may be stored in the programming register 1104. The internal command signals stored in the programming register 1104 may be provided to a latency & burst length controller 1106, and the latency & burst length controller 1106 may provide a control signal for controlling latency or a burst length in a data output to a column decoder 1110 via a column buffer 1108 or to an output buffer 1112.
An address register 1120 may receive an address ADD from the outside. A row address may be provided to a row decoder 1124 via a row address buffer 1122. In addition, a column address may be provided to the column decoder 1110 via the column buffer 1108. The row address buffer 1122 may further receive a refresh address generated by a refresh counter (not shown) therein in response to refresh commands LRAS and LCBR and may provide any one of the row address and the refresh address to the row decoder 1124. In addition, the address register 1120 may provide a bank signal for selecting a bank to a bank selection unit 1126.
The row decoder 1124 may decode the row address or the refresh address received from the row address buffer 1122 and enable word lines in a memory cell array 1101. The column decoder 1110 may decode the column address and perform a selection operation of bit lines in the memory cell array 1101. For example, a column selection line may be applied to the semiconductor memory device 1100 to perform a selection operation for the column selection line.
A sense amplifier 1130 may amplify data in a memory cell selected by the row decoder 1124 and the column decoder 1110 and provide the amplified data to the output buffer 1112. Data to be written in a memory cell may be provided to the memory cell array 1101 via a data input register 1132, and an input/output controller 1134 may control a data transfer operation through the data input register 1132.
In the embodiment described above, some of the configurations and operations performed for a repair operation may be performed by the memory management chip 1211. For example, address information related to a weak cell may be stored in the memory management chip 1211, and accordingly, row and column addresses for enabling a redundancy cell may be provided from the memory management chip 1211 to the at least one semiconductor memory device 1212. In addition, the memory management chip 1211 may output control codes, such as thermometer codes, for controlling a data line shifting operation and provide the control codes to the at least one semiconductor memory device 1212.
Referring to
The host interface HOST I/F receives a request of the host and transmits the request of the host to the processor PROS, or transmits data received from the non-volatile memory device 1310 to the host. The host interface HOST I/F may interface with the host using various protocols, such as Universal Serial Bus (USB), Man Machine Communication (MMC), Peripheral Component Interconnect-Express (PCI-E), Serial Advanced Technology Attachment (SATA), Parallel Advanced Technology Attachment (PATA), Small Computer System Interface (SCSI), Enhanced Small Device Interface (ESDI), and Intelligent Drive Electronics (IDE). Data to be transmitted to the non-volatile memory device 1310 or data received from the non-volatile memory device 1310 may be temporarily stored in the cache buffer CBUF.
The non-volatile memory device 1310 may be packaged using various types of packages, e.g., Package on Package (PoP), Ball grid arrays (BGAs), Chip scale packages (CSPs), Plastic Leaded Chip Carrier (PLCC), Plastic Dual In-Line Package (PDIP), Die in Waffle Pack, Die in Wafer Form, Chip On Board (COB), Ceramic Dual In-Line Package (CERDIP), Plastic Metric Quad Flat Pack (MQFP), Thin Quad Flatpack (TQFP), Small Outline (SOIC), Shrink Small Outline Package (SSOP), Thin Small Outline (TSOP), Thin Quad Flatpack (TQFP), System In Package (SIP), Multi Chip Package (MCP), Wafer-level Fabricated Package (WFP), and Wafer-Level Processed Stack Package (WSP).
Referring to
Referring to
Although a structure in which a signal transfer between semiconductor layers is performed through the TSV is described in the current embodiment, the current embodiment is not limited thereto, and may also be applied to a structure layered through wire bonding, interpose, or wire-formed tapes.
In addition, a signal transfer between semiconductor layers may be performed by an optical input/output connection. For example, the semiconductor layers may be connected to each other using a radiative method using a radio frequency (RF) wave or an ultrasound wave, an inductive coupling method using magnetic induction, or a non-radiative method using magnetic field resonance.
The radiative method is a method of transferring a signal in a wireless manner by using an antenna, such as a monopole antenna or a planar inverted-F antenna (PIFA). Radiation occurs while an electric field and a magnetic field varying over time affect each other, and when an antenna of the same frequency exists, a signal may be received to meet a polarization characteristic of an incident wave. The inductive coupling method is a method of generating a magnetic field that is strong in one direction by winding a coil several times and generating coupling by approaching a coil resonating at a similar frequency to the wound coil. The non-radiative method is a method using evanescent wave coupling by which an electronic wave moves between two media resonating with the same frequency through a near distance magnetic field. Each of the master chip 1831 and the slave chip 1832 may include a reference voltage generator (not shown) according to the embodiments of the inventive concepts. The memory module 1810 may communicate with the memory controller 1820 via a system bus. Data DQ, command/address CMD/ADD, a clock signal CLK, and so forth may be transmitted and received between the memory module 1810 and the memory controller 1820 via the system bus.
While the inventive concepts has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the following claims.
Number | Date | Country | Kind |
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10-2012-0093879 | Aug 2012 | KR | national |
10-2012-0093883 | Aug 2012 | KR | national |
This application claims the benefit of U.S. Patent Application No. 61/556,597, filed on Nov. 7, 2011, in the US Patent Office and Korean Patent Nos. 10-2012-0093879 and 10-2012-0093883, filed on Aug. 27, 2012 and Aug. 27, 2012, in the Korean Intellectual Property Office, the disclosures of all of which are incorporated herein in their entirety by reference.
Number | Date | Country | |
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61556597 | Nov 2011 | US |