KR100907822B1 - Method and device for indicating status of programmable nonvolatile memory - Google Patents

Abstract

The present invention relates to a method and an apparatus for indicating a state of a programmable nonvolatile memory, comprising: one or more antifuse cells operating as memory cells, one or more memory blocks for storing a predetermined bit of data, and one or more antifuse cells. In response to each memory block, one or more status indicators for indicating the usage status of the corresponding memory block are provided, and the status value of the status indicator of the data indicator is changed and displayed when data is written, deleted or modified. Data can be modified and deleted, as well as data written, in a non-volatile memory based fuse cell.

Non-volatile memory, anti-fuse, organic semiconductor devices, RFID,

Description

Method and appratus for indicating condition of programmable non-volatile memory

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonvolatile memory suitable for an RFID tag using an organic semiconductor, and more particularly, to a programmable nonvolatile memory using an antifuse cell capable of directly changing a stored value and a method of operating the same. .

The organic semiconductor device is a technology that is being developed to fabricate a semiconductor active device and a passive device on a flexible plastic material such as bending or bending. The organic semiconductor device has been applied in various fields. In particular, the RFID tag using the organic semiconductor device can be manufactured by directly printing on a flexible material such as plastic without using expensive semiconductor devices such as silicon. This has the advantage of reducing production cost and high utility.

1 is a block diagram illustrating a general configuration of an RFID tag. As illustrated, an RFID tag includes an analog circuit unit 11 for receiving an RF signal from a reader or sending an RF signal to the reader, and the analog circuit unit ( And a nonvolatile memory 13 that stores data processed by the digital circuit unit 12 and stores the data stored therein or reads and transmits the data. .

RFID technology is emerging as a new solution in management areas such as access control, commute management, logistics management, and parking management. For smooth management, the RFID tag must be stored as data desired by the user, or modified data can be modified. do. In particular, for an organic semiconductor-based RFID tag, a user-programmable non-volatile memory (field programmable non-volatile memory) based on an organic semiconductor should be present.

However, conventional organic semiconductor transistors are manufactured by coating a gate electrode and a polymer insulator on a flexible plastic substrate, and using an organic semiconductor such as pentacene as an active region. Conventional RFID tags could not provide a user programmable nonvolatile memory.

3 is an IEEE journal of solid-state circuits, vol. 42, no. In Fig. 1, "A 13.56-MHz RFID system based on organic transponders", a structure of a ROM (Read Only Memory) type memory disclosed for an organic semiconductor-based RFID tag is shown. Is a memory whose value cannot be changed afterwards. Since the organic semiconductor RFID implemented with such a memory cannot change a stored code value as desired by the user, the organic semiconductor RFID is not suitable for commodity logistics management and the like, thereby reducing the practicality of the RFID tag.

In response, Brian A. Mattis and Vivek Subramanian published "Stacked low-power field-programmable antifuse memories for RFID on plastic" in IDEM 2006, which proposed a programmable antifuse cell memory that can be applied to plastic-based RFID. The anti-fuse is a device whose characteristics are changed when a voltage above a program voltage is applied. The anti-fuse is connected to word lines and bit lines of a memory, respectively, and the program voltage is connected to the word lines and bit lines. To save the code value.

However, the anti-fuse cell memory described above is a non-volatile memory in the form of OTP (One Time Programmable) that can be programmed only once by a user, and is not suitable as a memory of an RFID tag used for distribution and the like requiring data modification.

The present invention is to provide a programmable nonvolatile memory that can be applied to RFID tags in the field of logistics and distribution in such organic semiconductor-based RFID.

More specifically, the present invention can be manufactured as an organic semiconductor device, while the user can directly store the desired code value when needed, or the stored code value can be applied to the anti-fuse RFID tag in the logistics distribution field A nonvolatile memory using a cell and a method of operating the same are provided.

According to an aspect of the present invention, there is provided a means for solving the above problems, one or more memory blocks consisting of one or more anti-fuse cells to operate as a memory cell, and stores a certain bit of data; And one or more antifuse cells, each corresponding to the one or more memory blocks, and including one or more state indicators indicating a usage state of the corresponding memory block.

In a programmable nonvolatile memory using an antifuse cell according to an aspect of the present invention, the one or more status indicators may include: a first antifuse cell programmed together when the corresponding memory block is programmed; It may consist of a second antifuse cell programmed when data stored in the memory block is invalid.

In addition, in the programmable non-volatile memory using the anti-fuse cell according to an aspect of the present invention, the one or more state indicators, respectively, when the first and second anti-fuse cells are not all programmed in the corresponding memory block Is an unused memory block, the first antifuse cell is programmed and the second antifuse cell is valid data is stored in the corresponding memory block when not programmed. When all the fuse cells are programmed, this may indicate that data stored in the corresponding memory block is invalid data.

In addition, in a programmable nonvolatile memory using an antifuse cell according to an aspect of the present invention, the one or more memory blocks, one end of each of the one or more antifuse cells operating as memory cells are connected to the same word line, and the other end thereof. Is connected to each corresponding bit line, wherein the one or more status indicators are respectively connected to word lines to which one end of the first and second antifuse cells are connected to the corresponding memory block, and the other end is for status indication. It may be connected to each of the bit lines designated by.

In addition, in the programmable non-volatile memory using an anti-fuse cell according to an aspect of the present invention, the one or more memory blocks, one end of one or more anti-fuse cells, each operating as a memory cell is grounded, the other end is one or more organic semiconductor Each of the one or more organic semiconductor transistors is turned on at the same time by a voltage applied to one word line, so as to apply a voltage applied from each bit line to the connected one or more antifuse cells, The one or more state indicators, one end of the first and second anti-fuse cells are respectively grounded, the other end is connected to the first and second organic semiconductor transistor, the first and second organic semiconductor transistor is a word connected to the memory block Are simultaneously turned on by the voltage applied to the line, One or more of the associated the voltage applied from the bit line may be formed are connected so as to apply the anti-fuse cell.

In addition, in accordance with another aspect of the present invention, a programmable non-volatile using an antifuse cell comprising one or more first and second antifuse cells each corresponding to one or more memory blocks to indicate a usage state of the corresponding memory block. In the method of operating a memory, when the data write request to the memory, the first anti-fuse cell is programmed to write the first anti-fuse cell corresponding to the memory block, while writing the data in the memory block, the memory block Indicating that valid data is stored in the; And programming a second antifuse cell corresponding to the memory block when the write data is requested to be deleted, to indicate that the memory block is invalid.

According to another aspect of the present invention, a method of operating a programmable nonvolatile memory using an antifuse cell may include: a second antifuse cell corresponding to a memory block in which the requested data is stored when a request for modification of data written in the memory is requested; Programming to indicate that the memory block is invalid; And writing modified data to a memory block in which the first antifuse cell is not programmed, and programming the first antifuse cell of the memory block to indicate that the memory block is valid. have.

According to the above-described configuration, the nonvolatile memory of the present invention can be manufactured with an organic semiconductor device, and by being able to program for each memory block, it is applied to an RFID tag based on an organic semiconductor device, and records data necessary for logistic distribution management. There is an excellent effect that can prevent unnecessary data from being used.

In addition, by adopting the nonvolatile memory structure according to the present invention, it is possible to fabricate an organic semiconductor RFID having a nonvolatile memory in which a user can directly store, modify, and delete data.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing in detail the operating principle of the preferred embodiment of the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In addition, the same reference numerals are used for parts having similar functions and functions throughout the drawings.

In addition, throughout the specification, when a part is said to be 'connected' to another part, it is not only 'directly connected' but also 'indirectly connected' with another component in between. Also includes. In addition, the term 'comprising' a certain component means that the component may be further included, without excluding the other component unless specifically stated otherwise.

3 is a diagram illustrating a structure of a programmable nonvolatile memory using an antifuse cell according to an embodiment of the present invention.

The programmable nonvolatile memory according to an aspect of the present invention implements an antifuse capable of manufacturing an organic semiconductor device as a memory cell. As shown in FIG. 3, the programmable nonvolatile memory includes one or more antifuse cells 311 that operate as a memory cell. One or more memory blocks 31 to 3n for storing a predetermined bit of data and one or more anti-fuse cells 411 and 412 correspond to the one or more memory blocks 31 to 3n, respectively. One or more status indicators 41 to 4n indicating the usage status of ˜3n).

The state indicators 41 to 4n may be implemented as one or more antifuse cells so as to display the states of the corresponding memory blocks 31 to 3n, respectively. In the present embodiment, two bit values of two antifuse cells are provided. To display three states. In the following description, two anti-tip devices provided in the state indicators 41 to 4n are provided for the purpose of distinguishing and explaining the anti-fuse cell 311 provided in the memory blocks 31 to 3n and operating as a memory cell. The fuse cells 411 and 412 are called first and second antifuse cells, respectively.

The antifuse cell 311 for memory cells provided in each of the memory blocks 31 to 3n and the first and second antifuse cells 41 of the state indicators 41 to 4n corresponding to the memory blocks 31 to 3n. ˜4n) are connected together _{to the} same word line W / L _{1 to} W / L _n , and are connected to different bit lines B / L ₁ to B / L _n , respectively, to the word line W / L. _It is selected by the voltage signal applied _{to 1 to} W / L _n , and programmed into the voltage signal applied to the bit lines B / L ₁ to B / L _n .

Antifuse generally has the property of being electrically open before a voltage above a certain program voltage is applied across the fuse.However, when a voltage above a certain program voltage is applied across the fuse, the fuse breaks the insulation of the fuse and is electrically conductive. The current characteristics at both ends vary depending on whether or not the program is performed. In the present invention, the antifuse cells 311, 411, and 412 use the characteristics of the antifuse to recognize the difference between the resistance value of the antifuse cell when the current flows and when the current flows as a bit value of 0 and 1. Can be. For example, when a voltage signal is simultaneously applied to the word lines (W / L _{1 to} W / L _n ) and the bit lines (B / L ₁ to B / L _n ), it is recognized as a bit value 1. If not programmed, bit value 0 is recognized. According to the above principle, a predetermined number of bits of data are stored in the antifuse cells 311 of the memory blocks 31 to 3n, and a two-bit memory block state value is written to the status indicators 41 to 4n.

In addition, the first antifuse cell 411 is selected and programmed together when the corresponding memory block 31 is programmed, and the second antifuse cell 412 is stored in the corresponding memory block 31. It is selected and programmed if the data becomes invalid.

The programmable nonvolatile memory implemented using the implemented antifuse cell has the structure shown in FIG. 4.

That is, as shown in FIG. 4, the programmable nonvolatile memory has n memory blocks, and in each memory block unit, two bits of status indication values PI and UI and m bits of data b _0. , ..., b _{m -1} ) can be recorded or read.

State indicating value of the two bits (PI, UI) is the first and second may be recognized from the anti-fuse cell (411 412), the m bits of data (b _0, ..., b _{m -1)} is the The antifuse cells 311 used as memory cells may be recognized.

In the present embodiment, the two-bit state indication value (PI, UI) may be defined as shown in Table 1 below.

Status indication (PI, UI) condition 00 Unused block of memory 10 Is a valid block of memory (stored data is valid) 11 Invalid memory block (stored data is invalid)

By further including the first and second antifuse cells 411 and 412 displaying the state indication values defined above, the programmable nonvolatile memory of the present invention is applied to an RFID tag and has a memory block having a state indication value of 00. Can be programmed to record the RFID tag value, and also change the status indication value of the memory block in which the data was previously stored to 11, program another memory block having a status indication value of 00, and store the data, You can change the RFID tag value. Therefore, by using the programmable nonvolatile memory according to the present invention, it is possible to change the RFID tag value several times within the capacity of the memory, instead of writing data only once. The operation method using the programmable nonvolatile memory of the present invention will be described in more detail later.

In addition, the programmable nonvolatile memory having the above-described structure may be implemented by using an organic semiconductor device on a flexible material that is flexible or bent, such as plastic.

5 and 6 show detailed circuit configurations of the programmable nonvolatile memory of the present invention.

Referring to FIG. 5, the one or more memory blocks 31-3n and the one or more state indicators 41-4n respectively ground one end of the antifuse cells 311, 411, and 412, respectively. The other end is connected to each of the organic semiconductor transistors T1 to Tn, and the organic semiconductor transistors T1 to Tn are simultaneously turned on by a voltage applied to each word line W / L ₁ to W / L _n . In this state, the voltage applied from each bit line B / L ₁ to B / L _n may be connected to the connected antifuse cells 311, 411, and 412. More specifically, the gate electrodes of the organic semiconductor transistors T1 to Tn are connected to word lines W / L ₁ to W / L _n , and one of the source and drain electrodes of the organic semiconductor transistors T1 to Tn is formed. The bit lines B / L ₁ to B / L _n are connected, and the remaining electrodes are connected to the antifuse cells 311, 411, and 412.

Referring to FIG. 6, the one or more memory blocks 311 and one or more state indicators 41 to 4n may respectively connect one end of the antifuse cells 311, 411, and 412 to corresponding word lines W / L _1. - it may be made by connecting to the W / L _n), and connect the other end of the anti-fuse cell (311 411 412) on each of the corresponding bit line (B / L ₁ - B / L _n), which.

The organic semiconductor transistors T1 to Tn are manufactured by coating a gate electrode and a polymer insulator on a highly flexible plastic substrate, and using an organic semiconductor such as pentacene as an active region. The structure is generally well known.

As shown in FIG. 6, in the case of implementing only the antifuse cell without using the organic semiconductor transistors T1 to Tn, the voltage drop by the organic semiconductor transistor can be prevented when the antifuse is programmed.

In addition, the antifuse cells 311, 411, and 412 used in the programmable nonvolatile memory according to an embodiment of the present invention may use an antifuse cell in which a capacitor and a diode are connected in series, as shown in FIG. 7A. And, as shown in Figure 7 (b), it is possible to use an anti-fuse cell implemented only with a capacitor.

The manufacturing method and structure of the anti-fuse cell described above are well known in the art, and thus detailed description thereof will be omitted.

As illustrated in FIGS. 8 and 9, the anti-fuse cells illustrated in FIGS. 7A and 7B, respectively, are applied when a voltage below the fuse program voltage is applied based on the fuse program voltage. While exhibiting a low current characteristic, when a fuse program voltage is applied, it is programmed to exhibit a high current characteristic, and maintains a high current characteristic after being programmed.

Therefore, by using the anti-fuse cell described above, by controlling the anti-fuse program operation, it is possible to write a variety of data in the memory block consisting of the anti-fuse cell, in addition, by recognizing the difference in the resistance value due to the current characteristic difference, Data written to a memory block consisting of antifuse cells can be read.

10 is a flowchart illustrating a method of operating a programmable nonvolatile memory according to the present invention.

Referring to FIG. 10, when there is an access request to the programmable nonvolatile memory according to the present invention (S101), if the access request is a data write request (S102), an unused memory block, that is, the first antifuse cell Data is stored in the unprogrammed memory block (S103), and a first antifuse cell corresponding to the memory block in which the data is stored is programmed to indicate that valid data is stored in the memory block (S104).

In addition, when the access request is a data deletion request (S104), a second antifuse cell corresponding to the memory block in which the data to be deleted is programmed is programmed to indicate that the memory block is invalid (S105).

In addition, when the access request is a data modification request (S106), a second antifuse cell corresponding to the memory block in which the modification request data is stored is programmed to indicate that the memory block is invalid (S107), The unused memory block, that is, the first antifuse cell stores the data to be modified in the unprogrammed memory block (S108), and the first antifuse cell of the memory block in which the data is stored is programmed so that the memory block is valid. To display (S109).

In addition, in the case of a data read request, data stored in a memory block may be read in the same manner as a memory composed of other existing antifuse cells (S110).

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be apparent to those skilled in the art.

1 is a block diagram showing the configuration of a general RFID tag,

2 is a block diagram illustrating a structure of a nonvolatile memory used in a conventional organic semiconductor based RFID tag.

3 is a structural diagram of a programmable nonvolatile memory according to an embodiment of the present invention;

4 is a state diagram of a memory block of a programmable nonvolatile memory according to an embodiment of the present invention;

5 is a circuit diagram illustrating a detailed implementation of a programmable nonvolatile memory according to an embodiment of the present invention;

6 is a circuit diagram illustrating another implementation of a programmable nonvolatile memory according to another embodiment of the present invention;

7 is an equivalent circuit diagram of an antifuse applied to a programmable nonvolatile memory according to an embodiment of the present invention;

8 and 7 are operation state diagrams of the anti-fuse shown in (a) and (b) of FIG.

10 is a flowchart illustrating a method of operating a programmable nonvolatile memory according to an embodiment of the present invention.

Claims (9)

delete In the status indicating device consisting of one or more anti-fuse cells, indicating the state of use of the memory block when writing, deleting and modifying data in the memory block, A first antifuse cell programmed together when the memory block is programmed; And A second antifuse cell programmed when data stored in the memory block is invalid; Device for indicating the status of the programmable nonvolatile memory, comprising a. The apparatus of claim 2, wherein the state indicating device comprises: The memory block is an unused memory block when both the first and second antifuse cells are not programmed, and the memory block when the first antifuse cell is programmed and the second antifuse cell is not programmed. A state of the programmable non-volatile memory that indicates that the programmed and usable data is stored, and that the data stored in the memory block is invalid data when both of the first and second antifuse cells are programmed. Pointing device. The method of claim 2, wherein the memory block, And connecting one end of at least one antifuse cell that operates as a memory cell to the same word line, and the other end to a corresponding bit line, respectively. The apparatus of claim 4, wherein the state indicating device comprises: And connecting one end of the first and second antifuse cells to a word line to which the memory block is connected, and the other end to a bit line designated for status indication, respectively. The method of claim 2, wherein the memory block, One end of at least one antifuse cell acting as a memory cell, the other end being connected to one or more organic semiconductor transistors, respectively, wherein the one or more organic semiconductor transistors are simultaneously turned on by a voltage applied to one word line, And applying a voltage applied from each bit line to the connected one or more antifuse cells. The apparatus of claim 6, wherein the state indicating device comprises: One end of the first and second antifuse cells is grounded, and the other end is connected to the first and second organic semiconductor transistors, and the first and second organic semiconductor transistors are simultaneously applied by a voltage applied to a word line to which the memory block is connected. And a state of the programmable non-volatile memory, which is turned on and connected to apply the voltage applied from each bit line to the one or more connected anti-fuse cells. 1. A method of indicating a state of a programmable nonvolatile memory using an antifuse cell, the antifuse cell comprising one or more first and second antifuse cells corresponding to one or more memory blocks, respectively, to indicate a use state of the corresponding memory block. When a data write request is made to the memory, valid data is stored in the memory block by programming a first antifuse cell corresponding to the memory block while writing data to a memory block in which the first antifuse cell is not programmed. Displaying; And And programming a second antifuse cell corresponding to the memory block upon the request for erasing the recorded data to indicate that the memory block is invalid. The method of claim 8, When requesting to modify the data recorded in the memory, programming a second antifuse cell corresponding to the memory block in which the requested data is stored to indicate that the memory block is invalid; And And recording modified data in a memory block in which the first antifuse cell is not programmed, and programming the first antifuse cell of the memory block to indicate that the memory block is valid. How to indicate the status of programmable nonvolatile memory.

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