JP2002014874A - Semiconductor memory, code distributing method, media reproducing method, and machine readable medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor memory capable of preventing the theft of a chip and the leakage of data stored in the chip. SOLUTION: This semiconductor memory, which has a memory array part for storing data and a power source potential detecting means for outputting an operation permit signal when the power source potential inside the device is raised to an operable level and permits a read/write operation from/to the memory array part at the time of outputting the operation permit signal, is provided with a safety circuit for permitting the read/write operation from/to the memory array part only when specific code information is inputted from the outside part at the time of outputting the operation permit signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor memory device such as a DRAM.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram showing a schematic configuration of a conventional semiconductor memory device.

In this semiconductor memory device, the power supply is turned on, and when the internal potential thereof reaches a predetermined value, a CHRDY signal is output from a power supply potential detection circuit 107. Thereafter, the device is brought into a required operation ready state. Become.

That is, when writing / reading data to / from the memory cell array 101, a row address AR and a column address AC are input to a row decoder 102 and a column decoder 104, respectively. By activating OE, desired data stored in the memory cell array 101 becomes
The signal is output to the I / O pin via the selector 103 and the write / read circuit 105. On the other hand, when writing data, by activating the write control signal WE, the write data input from the I / O pin is transferred to the write / read circuit 105 and the selector 1.
Through 03, data is written to a desired memory cell in the memory cell array 101.

[0005]

However, the above conventional semiconductor memory device has the following problems.

Conventionally, it has been expected that a chip body will be stolen at the time of shipment, or a defective product which should have been discarded will be packaged by a third party and sold in a market. It is fully anticipated that when a semiconductor storage device such as the one described above becomes a carrier of media transport, a semiconductor storage device storing personal data can easily be transferred to human hands.

[0007] From such a point, there has been a demand for a device structure and a countermeasure capable of preventing theft of the chip.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a semiconductor memory device capable of preventing theft of a chip and leakage of data stored in the chip. It is to provide. Another object of the present invention is to provide a code distribution method that can further avoid the risk of chip theft and a media reproduction method that can prevent theft of personally owned media information.

[0009]

In order to achieve the above object, in a semiconductor memory device according to the present invention, a memory array for storing data and a power supply potential in the device rise to an operable level. A power supply potential detecting means for outputting an operation permission signal when the operation permission signal is output, wherein when the operation permission signal is output, a read / write operation to the memory array unit is permitted. A safety circuit is provided which permits a read / write operation to the memory array unit only when specific code information is input from outside.

[0010] In the semiconductor memory device according to the second aspect of the present invention, in the semiconductor memory device according to the first aspect, the safety circuit may include a chip identification information set unique to the semiconductor storage device and the specific code information. A comparison circuit for comparing the coincidence and non-coincidence of the data, and only when the comparison result of the comparison circuit coincides, the read / write operation to the memory array section is permitted.

[0013] In the code distribution method according to the third aspect of the present invention, the step of waiting for the key number written on the package of the sold semiconductor storage device to be input from an external terminal includes the steps of: Using the input key number as a search key, a process of searching a database storing a sales list corresponding to the package purchaser who purchased the semiconductor storage device, and a sales list corresponding to the key number were searched. when,
And returning a specific code information to the external terminal to which the key number has been input.

In the code distribution method according to a fourth aspect of the present invention, in the code distribution method according to the third aspect, the input of the key number and the return of the specific code information include:
It is characterized by being performed online.

According to a fifth aspect of the present invention, in the code distribution method according to the third or fourth aspect, the semiconductor storage device is the semiconductor storage device according to the first or second aspect. The specific code information is the specific code information input to the semiconductor memory device.

According to a sixth aspect of the present invention, there is provided a media reproducing method, wherein media information is stored in the semiconductor memory device according to the first aspect, and the media information is distributed to the semiconductor memory device by the code distribution method according to the fifth aspect. After receiving the sent matter attached with the specific code information and setting the semiconductor memory device to a reproducing device, inputting the specific code information to the semiconductor memory device via the reproducing device, Performing a collation process between the chip identification information uniquely set to the semiconductor storage device and the specific code information, and reproducing the media information in the semiconductor storage device by the reproduction device only when the collation results match; It is characterized by.

According to a seventh aspect of the present invention, in the machine readable medium, a step of waiting for a key number written on a package of the sold semiconductor storage device to be input from an external terminal; Searching at least a database storing a sales list corresponding to a package purchaser who has purchased the semiconductor storage device using at least the input key number as a search key; and searching the sales list corresponding to the key number. And a step of returning specific code information for enabling the semiconductor storage device to the external terminal to which the key number has been input.

[0016] In the machine readable medium according to the present invention, the key number is input from the external terminal and the specific code is input to the external terminal. Reply of information,
A processing program configured to be performed online is recorded.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 is a block diagram showing a schematic configuration of a semiconductor memory device according to a first embodiment of the present invention.

The semiconductor memory device 10 has, for example, a DRA
It has a memory cell array 11 composed of M chips and having memory cells storing data of “1” or “0” arranged in a matrix. Memory cell array 11
To write data to the row address A
R and the column address AC are input to the row decoder 12 and the column decoder 14, respectively, and the write control signal WE is activated. Thus, the write data input from the I / O pin is written to a desired memory cell in the memory cell array 11 via the write / read circuit 15 and the selector 13.

On the other hand, in the case of reading, the row address AR
And the column address AC to the row decoder 12 and the column decoder 14, respectively, and by activating the read control signal OE, desired data stored in the memory cell array 11 is changed to the selector 13 and the write / read circuit. After that, it is output to the I / O pin.

After the power supply is turned on, the power supply potential detection circuit 17 detects the "H" level CHRDY signal when its internal potential reaches a predetermined value, that is, after confirming that the power supply potential has risen normally. And output this CHRD
The Y signal is input to a safety circuit 18 which is a feature of the present invention.

When starting up the semiconductor memory device, the safety circuit 18 supplies specific code data C that matches the chip ID 16 which is identification information unique to the chip.
If the OD is not input, this is a circuit for preventing the chip body from operating, and outputs a CRY signal to the write / read circuit 15 or the like as a control signal therefor.

As shown in FIG. 2, the configuration of the safety circuit 18 is a comparison circuit 18a for comparing the chip ID 16 with the code data COD for matching or non-matching, a comparison result signal of the comparison circuit 18a and a power supply potential detecting circuit. And an AND gate 18b which takes an AND logic with the CHRDY signal from 17 and outputs the result as the CRY signal. Note that the code data COD is externally input through the I / O pin 19.

More specifically, according to the safety circuit 18, the code data COD input after the power supply is turned on.
However, the redundancy process (R / D process: re
The comparator circuit 18a compares whether or not the data matches the chip ID 16 engraved on the chip at the time of “dundancy”. If they match, the output of the comparator circuit 18a is at the “H” level. Becomes When the input code data COD matches, “H” is output.
The level CDY signal is output. This CD
The Y signal is a signal for permitting the start of the normal operation of the chip, and when the code data COD does not match, the chip prohibits its own normal operation.

Here, the chip ID 16 will be described.

Normally, in the case of a DRAM, at the time of shipment, a chip ID composed of a combination of fuses different for each chip is engraved on each chip in a redundancy process described later. This is originally used to confirm the identity of chips in returned goods analysis and the like. More specifically, at the time of fuse blowing in the R / D process,
The site name, lot number, wafer number, and x / y position on the wafer of the chip are coded, and an ID fuse (ie, chip ID) is blown before shipment. That is, the chip ID is in a one-to-one correspondence for each chip, there is no identical one, and the blow content can be read out by a special command after packaging.

Conventionally, this chip ID is mainly used for process control and returned goods analysis. That is, in the process management, for example, when a lot of defects occur in the package test, the lot dependency and the wafer distribution can be tracked. Further, in the returned product analysis, the characteristics of the defective chip can be easily traced.

The most characteristic feature of the present invention is that the existing chip ID is used for chip-specific security.

FIG. 3 is a flowchart showing a process at the time of shipping.

First, after the wafer is manufactured (Step S1)
1) A wafer test is performed (step S12). As a result of this test, the defective cell is switched to a spare cell.
That is, the defective cell is switched to the spare cell by cutting the fuse. In this wafer test process, fuse cut information indicating which fuse is cut is generated.

In the subsequent redundancy process (step S1)
3) Based on the fuse cut information generated in the wafer test process (step S12), the fuse cut for switching to the spare cell is performed. At the same time, the fuse cut for generating the chip ID is also performed.

In the subsequent assembly process (step S
14) The wafer is diced and cut into individual chips, and in a manufacturing test process (step S15), the operation of all cells including the speed test is tested, and only non-defective products are shipped (step S16). ).

FIG. 4 is a flowchart showing a sequence during operation of the present embodiment.

After power-on (step S21), an encryption input command is input (step S22), and an I / O
The code data COD specified for each chip is input through the O pin 19 in accordance with the internal clock (step S23). The input code data COD is the chip I
If it matches D (step S24), the "key" is opened and the chip becomes operable (step S2).
5). If not, the process returns to step S21. That is, the chip is locked, and thereafter no write / read operation is performed on the chip.

[Second Embodiment] In this embodiment, a system for transmitting the code data COD to a user after shipment of a chip constituted by the semiconductor memory device of the first embodiment through a route different from a shipping route. It is to explain. As a result, the security of the present invention can be further emphasized.

At present, each plastic package has a key number, which basically exists in lot units. That is, the target lot can be traced from this key number. Therefore, FIG.
Establish a distribution route as shown in

FIG. 5 is a distribution route diagram showing a code distribution method according to the second embodiment of the present invention. In the example shown in the figure, a method of distributing code data COD from a chip vendor 21 to a system provider 22 is shown.

First, when chips are shipped from the chip vendor 21 to the system vendor 22 (T11), the system vendor 22 sends the key number to the ID database 23 of the chip vendor 21 online using a terminal. (T12).

The ID database 23 determines whether the inquirer is an appropriate partner from the sales list. In other words, the user waits for the key number written on the package of the sold chip to be input online from outside, and when the key number is input, purchases the chip using the input key number as a search key. ID database 23 storing sales lists corresponding to package purchasers
Search for. When the sales list corresponding to the key number is searched, the specific code data COD is returned to the system supplier 22 who has input the key number (T13).

As a result, the system provider 22 constructs a system so that the purchased chip can be moved based on the transmitted code data COD, for example.

In this embodiment, the code data COD, which is a key for operating the chip, is transmitted through a route different from the chip shipping route, so that it is difficult for a third party to obtain the code data COD. And as a result,
The risk of chip theft can be further avoided.

Note that the code distribution method of the present invention can be realized by reading out the above-mentioned processing program from a medium such as a CD-ROM storing a processing program for executing the code distribution method of this embodiment by a computer. Is also possible.

[Third Embodiment] In the present embodiment, when the chip shown in the first embodiment is used for a personal media medium (music, image, etc.), the reproduction of the media information is realized. This is an explanation of the method.

FIG. 6 is a distribution route diagram for realizing the media playback method according to the third embodiment of the present invention. Elements common to those in FIG. 5 are denoted by the same reference numerals and description thereof is omitted. I do.

The exchange between the chip vendor 21 and the media vendor 31 in this embodiment is the same as the exchange between the chip vendor 21 and the system vendor 22 shown in FIG. 5, and in this embodiment, The system vendor 22 is replaced with a media vendor 31, and the media vendor 31 and the individual user 32 communicate with each other.

In this embodiment, as shown in FIG. 6, the method of shipping chips (which is assumed to be constituted by a memory card in this embodiment) and the method of delivering code data COD are the same as in the second embodiment. It is. Thereafter, the media distributor 31 stores the media information such as music and images on the memory card purchased from the chip distributor 21, and furthermore, on the surface of the storage case for storing the memory card,
The code data COD received from the chip distributor 21 is described and sent to the individual user 32 who ordered the memory card (TS14, T15).

The individual user 32 takes out the memory card 60 from the storage case and inserts it into the card slot 52 of the media reproducing device 50 as shown in FIG. Playback equipment 5
In the case of 0, when the memory card 60 is inserted, a display prompting input of an ID is displayed on the display screen of the operation panel 51, for example. At this time, the individual user 32 inputs the code data COD described in the storage case as an ID from the operation panel 51. As a result, the collation between the code data COD and the chip ID as described in the first embodiment is performed.

The individual user need only input the ID for the first time, and the input ID is stored in the media playback device 50. When the memory card 60 is inserted, the media reproducing device 50 automatically inputs the ID stored so far into the semiconductor memory device of the present invention, and performs collation with the chip ID. If they match, the key is opened, and the playback sound of the media can be obtained from the earphone 53 or the like. That is, if you do not know the ID attached to the media,
Can't play. This can prevent theft of personally owned media information.

[0049]

As described above in detail, according to the semiconductor memory device of the present invention, the read / write of the device must be performed unless specific code information corresponding to the chip identification information set unique to the semiconductor memory device is input. Since the write operation cannot be started, it is possible to prevent the chip constituted by the semiconductor memory device of the present invention from being stolen and the data stored in the chip from being leaked to a third party.

According to the code distribution method of the present invention, a specific code information which is a key for operating the chip is purchased by a purchaser on a route different from the shipping route of the chip constituted by the semiconductor memory device of the present invention. , It becomes difficult for a third party to obtain specific code information, and the risk of chip theft can be further avoided.

According to the media reproducing method of the present invention, a person who does not know the specific code information accompanying the semiconductor storage device storing the media information cannot reproduce the media information. This can prevent theft of personally owned media information.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a semiconductor memory device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a comparison circuit in FIG. 1;

FIG. 3 is a flowchart showing a process at the time of shipping.

FIG. 4 is a flowchart showing a sequence at the time of operation of the first embodiment.

FIG. 5 is a distribution route diagram illustrating a code distribution method according to a second embodiment of the present invention.

FIG. 6 is a distribution route diagram for realizing a media reproduction method according to a third embodiment of the present invention.

7 is an external view of a media playback device that plays back a media medium received by an individual user in FIG. 6;

FIG. 8 is a block diagram showing a schematic configuration of a conventional semiconductor memory device.

[Explanation of symbols]

 Reference Signs List 11 memory cell array 12 row decoder 13 selector 14 column decoder 15 write / read circuit 16 chip ID 17 power supply potential detection circuit 18 safety circuit 18a comparison circuit COD code data

Claims (8)

[Claims] A memory array section for storing data; and a power supply potential detecting means for outputting an operation permission signal when a power supply potential inside the device rises to an operable level. In the semiconductor memory device permitting a read / write operation to the memory array unit, the read / write operation to the memory array unit is permitted only when specific code information is externally input when the operation permission signal is output. A semiconductor memory device comprising a safety circuit. 2. The safety circuit according to claim 1, further comprising: a comparison circuit for comparing whether the chip identification information set unique to the semiconductor memory device and the specific code information match or not, and wherein the comparison results of the comparison circuits match. 2. The semiconductor memory device according to claim 1, wherein a read / write operation to said memory array section is permitted only when said operation is performed. A step of waiting for a key number written on a package of the sold semiconductor storage device to be input from an external terminal; and at the time of inputting the key number, at least the input key number as a search key. A process of searching a database storing a sales list corresponding to a package purchaser who has purchased the semiconductor storage device; and, if a sales list corresponding to the key number has been searched, an external terminal having input the key number. And returning a specific code information to the code distribution method. 4. The code distribution method according to claim 3, wherein the input of the key number and the return of the specific code information are performed online. 5. The semiconductor memory device according to claim 1, wherein the specific code information is the specific code information input to the semiconductor memory device. The code distribution method according to claim 3 or 4, wherein: 6. A method for storing media information in a semiconductor memory device according to claim 1 and transmitting the specific code information distributed by the code distribution method according to claim 5 to the semiconductor memory device. After receiving the sent product and setting the semiconductor storage device in a playback device, the specific code information is input to the semiconductor storage device via the playback device, and a chip identification uniquely set for the semiconductor storage device is received. A media reproducing method, comprising: performing collation processing of information with the specific code information; and reproducing the media information in the semiconductor storage device by the reproducing device only when the collation results match. 7. A step of waiting for a key number written on a package of the sold semiconductor storage device to be input from an external terminal; and at the time of inputting the key number, at least the input key number as a search key; Searching a database in which a sales list corresponding to a package purchaser who purchased the semiconductor storage device is stored; and when a sales list corresponding to the key number is searched, an external terminal that has input the key number For
Returning a specific code information for enabling the semiconductor memory device to operate. A machine-readable medium having recorded thereon a processing program. 8. A processing program recorded such that the input of the key number from the external terminal and the return of the specific code information to the external terminal are performed online. 8. The machine readable medium according to claim 7.