News Column

Patent Application Titled "Data Storing Circuit and Repair Circuit of Memory Device Including the Same" Published Online

January 30, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- According to news reporting originating from Washington, D.C., by VerticalNews journalists, a patent application by the inventor JEONG, Jeongsu (San Jose, CA), filed on July 6, 2012, was made available online on January 16, 2014.

No assignee for this patent application has been made.

Reporters obtained the following quote from the background information supplied by the inventors: "Exemplary embodiments of the present invention relate to a data storing circuit, and more particularly, to a data storing circuit including a one-time program cell, such as a laser fuse or an e-fuse.

"A laser fuse outputs a signal, or data, whose logic value becomes different according to whether the fuse is cut or not, and an e-fuse outputs a signal whose logic value becomes different according to whether its gate oxide is ruptured or not. The laser fuse and the e-fuse are being used for different semiconductor devices such as a memory device.

"Generally, a memory device uses a redundancy scheme, which uses a redundancy cell and improves production yield by substituting a defective cell with the redundancy cell. When a wafer process is ended and a defective cell is detected during a test process, the detected defective cell is to be substituted with a redundancy cell. To substitute the defective cell with a redundancy cell, the address of the detected defective cell is to be stored. Generally, a laser fuse or an e-fuse is used to store the address of the defective cell. However, the laser fuse or the e-fuse has a feature that once they are programmed (that is, once the logic value of data is changed), it is difficult to change the logic value of the data. For example, it is difficult to recover the laser fuse once the laser fuse is cut, and it is difficult to recover the e-fuse once the e-fuse is ruptured. For this reason, a memory cell formed of a laser fuse or an e-fuse is referred to as a one-time program cell.

"FIG. 1 illustrates information stored in a data storing circuit that is formed of a one-time program cell.

"Referring to FIG. 1, the data storing circuit 100 includes storages 111 to 117 for storing a 7-bit data and a storage 121 for storing validity of the data. Each of the storages 111 to 117 is formed of -a one-time program cell' (that is, a cell whose data logic value may be changed only once) such as a laser fuse or an e-fuse.

"The 7-bit data stored in the storages 111 to 117 is data that the data storing circuit 100 stores, and the signal stored in the storage 121 signifies the validity of the data stored in the storages 111 to 117. For example, when the signal stored in the storage 121 has a value of '1', the data stored in the storages 111 to 117 is determined to be a valid data, and when the signal that is stored in the storage 121 has a value of '0', the data stored in the storages 111 to 117 is determined to be an invalid data.

"The data logic value of a one-time program cell may be changed only once from the initial value. For instance, when the initial value is '0', the data logic value of the one-time program cell may be changed once to '1', and when the initial value is '1', the data logic value of the one-time program cell may be changed once to '0'. Hereafter, for illustration purposes, it is assumed that the initial value of the one-time program cell is '0'.

"It is also assumed that the data storing circuit 100 stores data as shown in the following Table 1.

"TABLE-US-00001 TABLE 1 EN D6 D5 D4 D3 D2 D1 D0 1 1 0 1 1 1 0 0

"According to Table 1, the data stored in the data storing circuit 100 is '1011100'; the stored data is a valid data as indicated by '1' is stored in the storage 121) and may be used for further processing. If it is decided that the stored data is erroneous after the data of '1011100' is stored in the data storing circuit 100, the data stored in 'EN' is to be changed to '0' to prevent the data stored in the data storing circuit 100 from being used. However, since the storage 121 is formed of a one-time program cell, it is difficult to change the data stored in the storage 121 back to '0'."

In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventor's summary information for this patent application: "An embodiment of the present invention is directed to a method that may effectively determine a valid program in a data storing circuit using, for example, a one-time program cell.

"In accordance with an embodiment of the present invention, a data storing circuit includes: a storage unit configured to store a multi-bit data and a validity signal representing validity of the data; and a decision unit configured to determine validity of the multi-bit data by comparing one-bit data of the multi-bit data with the validity signal.

"In accordance with another embodiment of the present invention, a repair circuit of a memory device includes: a storage unit configured to store a multi-bit repair address and a validity signal representing validity of the repair address; a decision unit configured to determine validity of the repair address by comparing one-bit data of the multi-bit repair address with the validity signal and generate a validity determination signal in response to the comparison; a latch unit configured to store the validity determination signal and the repair address; and an address comparison unit configured to generate, when the validity determination signal is enabled, a repair signal by comparing an input address and the repair address stored in the latch unit.

"In accordance with yet another embodiment of the present invention, an integrated circuit chip includes: an e-fuse array configured to store a plurality of data sets, each of which includes a multi-bit data, and validity signals that correspond to the data sets, respectively, and output a data set of the data sets and the corresponding validity signal at each cycle of a clock; a decision unit configured to generate validity determination signals, wherein the validity determination signals are each generated by comparing a respective one of the validity signals with one-bit data of the data set corresponding to the validity signal; a bus configured to transfer the validity determination signals and the data sets corresponding to the validity determination signals; a selection signal generation unit configured to generate a plurality of selection signals in response to the clock; and a plurality of latch sets configured to each store, in response to an enabled one of the selection signals, one of the validity determination signals and the data set corresponding to the validity determination signal.

BRIEF DESCRIPTION OF THE DRAWINGS

"FIG. 1 illustrates information stored in a data storing circuit that is formed of a one-time program cell.

"FIG. 2 is a block view illustrating a data storing circuit in accordance with an embodiment of the present invention.

"FIG. 3 is a block view illustrating a memory device including the data storing circuit shown in FIG. 2.

"FIG. 4 is a block view illustrating an integrated circuit chip in accordance with an embodiment of the present invention.

"FIG. 5 is a block view illustrating a selection signal generator 430 shown in FIG. 4."

For more information, see this patent application: JEONG, Jeongsu. Data Storing Circuit and Repair Circuit of Memory Device Including the Same. Filed July 6, 2012 and posted January 16, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=3453&p=70&f=G&l=50&d=PG01&S1=20140109.PD.&OS=PD/20140109&RS=PD/20140109

Keywords for this news article include: Patents.

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Source: Politics & Government Week


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