JP6091836B2 - Identifier generation method and identifier generation apparatus for semiconductor integrated circuit - Google Patents

Description

  The present invention relates to an identifier generation method and an identifier generation apparatus for a semiconductor integrated circuit.

  Reducing the incidence of defective products in the manufacturing process of semiconductor integrated circuits, that is, improving the yield is one of the important issues for semiconductor manufacturers. In order to improve the yield, the cause of the defect is clarified based on the history information such as the manufacturing history of each semiconductor integrated circuit, the manufacturing line such as the manufacturing line and the manufacturing lot, and the inspection history such as the inspection type and the inspection result. It is desirable that

  As one of means for specifying such history information, each semiconductor integrated circuit is given an identifier for distinguishing the semiconductor integrated circuit from other semiconductor integrated circuits, and the history information of the semiconductor integrated circuit is obtained. It is possible to manage on the database in association with the identifier.

  Assigning an identifier to each semiconductor integrated circuit has the advantage of not only improving the yield, but also helping to quickly identify and analyze a defective part even when a defect is discovered after manufacturing.

  Conventionally, as a method for assigning an identifier to a semiconductor integrated circuit, a method of providing a nonvolatile memory in the semiconductor integrated circuit and writing the identifier in the nonvolatile memory has been known. However, since the process of creating a nonvolatile memory inside a semiconductor integrated circuit is generally complicated, there is a case where a semiconductor integrated circuit has a nonvolatile memory as an original standard and an identifier can be written therein. Except for this, there arises a problem that the number of processes and manufacturing costs increase.

  As another method, a method of directly marking a semiconductor integrated circuit with a laser, a method of cutting a fuse using a laser, and the like have been known. However, a separate process for marking and cutting the fuse is required. Therefore, there arises a problem that the number of steps and the manufacturing cost increase as in the above method.

  Patent Document 1 discloses a technique for suppressing an increase in the number of processes and manufacturing costs, which is a problem of a conventional identifier generation method. The invention according to Patent Document 1 is an identifier generation method for generating an identifier for identifying a plurality of semiconductor integrated circuits having the same configuration from each other, and the identifier assigned to each of the plurality of semiconductor integrated circuits is the same. An identifier generation method for generating an identifier based on an analog signal output from the semiconductor integrated circuit under conditions.

JP 2011-9691 A (published January 13, 2011)

  In the method of Patent Document 1, there is room for improvement in the reliability of the identifier.

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide an identifier generation method capable of generating an identifier with higher reliability than in the past.

In order to solve the above problems, an identifier generation method according to the present invention is an identifier generation method for generating an identifier for identifying a plurality of semiconductor integrated circuits having the same configuration from each other. An identifier generating step for generating an identifier to be assigned to each of the circuits based on power supply current values for a plurality of predetermined internal states in a non-operating state of the semiconductor integrated circuit , and in the identifier generating step, Based on an identification number list obtained by rearranging internal state identification numbers for identifying a plurality of defined internal states according to the magnitude relationship of power supply current values with respect to the internal states corresponding to each internal state identification number The identifier is generated .

An identifier generation apparatus according to the present invention is an identifier generation apparatus that generates an identifier for mutually identifying a plurality of semiconductor integrated circuits having the same configuration, and is an identifier assigned to each of the plurality of semiconductor integrated circuits Is generated based on power supply current values for a plurality of predetermined internal states in a non-operating state of the semiconductor integrated circuit, and the identifier generating unit includes the plurality of predetermined The above identifier is generated based on an identification number list obtained by rearranging internal state identification numbers for identifying internal states according to the magnitude relationship of power supply current values with respect to the internal states corresponding to the internal state identification numbers. to, it is characterized in that.

  According to one embodiment of the present invention, it is possible to provide an identifier generation method and an identifier generation apparatus that can generate an identifier with higher reliability than conventional ones.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating a configuration of an identifier generation device according to a first embodiment of the present invention. FIG. 3 is a diagram illustrating an identifier generation method according to an embodiment of the present invention. 1 is a block diagram showing a configuration of a liquid crystal driver, showing a semiconductor integrated circuit to which an identifier is to be assigned in an embodiment of the present invention. FIG. 1 is a circuit diagram of a reference voltage generation circuit having a gamma resistance in a liquid crystal driver, showing a semiconductor integrated circuit to which an identifier is to be assigned in an embodiment of the present invention. 4 is a graph for explaining an embodiment of the present invention and showing a value of an output voltage from a liquid crystal driver. FIG. 10 is a graph illustrating a power supply current value for each of a plurality of internal states of the same liquid crystal driver, illustrating an embodiment of the present invention. FIG. 11 is a diagram illustrating an embodiment of the present invention and an explanatory diagram relating to a modified example of the identifier generation method. FIG. 11 is a diagram illustrating an embodiment of the present invention and an explanatory diagram relating to a modified example of the identifier generation method. FIG. 10 is a graph illustrating a second embodiment of the present invention, in which a result of measuring a power supply current value supplied to a specific power supply terminal of a liquid crystal driver is plotted.

Embodiment 1
An identifier generation method for a semiconductor integrated circuit according to an embodiment of the present invention will be described below with reference to the drawings.

  First, FIG. 3 shows a block diagram of a liquid crystal driver having an analog output function as an example of a semiconductor integrated circuit to be given an identifier in the identifier generating method according to the present embodiment. The liquid crystal driver shown in FIG. 3 is a semiconductor integrated circuit for outputting a drive signal (analog signal) for driving a liquid crystal panel (not shown) of the liquid crystal display.

  The operation of the liquid crystal driver will be briefly described with reference to FIG. As shown in FIG. 3, the liquid crystal driver includes a shift register, sampling memory, hold memory, level shifter, DA converter, output operational amplifier, data latch, and reference voltage generation circuit.

  RGB input is a video input signal indicating digitally the colors (R: red, G: Green, B: Blue) and luminance (brightness) displayed on the liquid crystal panel, and is a signal input serially to the liquid crystal driver. is there. The liquid crystal driver performs an operation of converting a digital value indicated by RGB input into an analog value (voltage) and outputting the analog value (voltage) to the liquid crystal panel.

  First, the liquid crystal driver holds (latches) the video data from the RGB input in the data latch at the timing of the operation clock (CK). The held video data is held in the sampling memory by a sampling clock generated by the shift register based on CK. By sequentially storing RGB input signals in the sampling memory at the timing of the shift clock, the video data input serially from the RGB input is serial-parallel converted. This allows video data to be processed in parallel. The video data stored in the sampling memory is transferred to the hold memory by a signal from the LS.

  The data transferred to the hold memory undergoes voltage conversion by the level shifter and is given to the DA converter. The video data from the RGB input is a digital signal of about 3V, but the signal for operating the liquid crystal panel is a voltage of more than a dozen V, so voltage conversion is necessary.

  The video data (digital value) input to the liquid crystal panel is converted into a corresponding voltage (analog value) by the DA converter, and further impedance-converted by the output operational amplifier and output to the liquid crystal panel.

  FIG. 4 is a diagram showing a configuration of a reference voltage generating circuit in the liquid crystal driver. The reference voltage generation circuit creates a voltage that the DA converter selects in accordance with the video data (digital value). As shown in FIG. 4, the reference voltage generation circuit includes a plurality of serially connected resistors (m1 to mn), both ends of a serially connected resistor, and V0H to VkH that apply voltage in the middle (n and k are natural numbers). ). When the maximum voltage and the minimum voltage for driving the liquid crystal panel are input to V0H and VkH that apply the voltages at both ends, a voltage divided by resistors is generated between the serially connected resistors m1 to mn. For example, 256 gradation voltages can be created by using 256 resistors (m1 to m256).

  The brightness of the liquid crystal panel changes depending on the voltage output from the liquid crystal driver, but the brightness does not change uniformly with respect to the applied voltage change. It is necessary to increase the difference in voltage applied at. For this reason, in the reference voltage generation circuit, the resistance values of m1 to mn are changed so that the voltage created by resistance division matches the characteristics of the liquid crystal panel, so that the liquid crystal driver has output characteristics as shown in FIG. .

  FIG. 5 is a plot of video data (for example, data indicating 256 gradations to data indicating 256 gradations) given to the liquid crystal driver on the horizontal axis, and output of the liquid crystal driver on the vertical axis.

  As shown in FIG. 4, V1H to Vk-1H that apply voltages in the middle of the reference voltage generation circuit are for changing the output characteristics.

  Further, the power supply VDD and VLS are connected to the liquid crystal driver. VDD provides a voltage necessary for the operation of the shift register, data latch, sampling memory, hold memory, and level shifter. VLS provides a voltage necessary for the operation of the level shifter, DA converter, output operational amplifier, and reference voltage generation circuit. Currents IDD and ILS flowing from power supply VDD and VLS to GND can be measured by connecting an ammeter to each of VDD and VLS.

  Hereinafter, a method for generating the identifier based on the power supply current value of the liquid crystal driver shown in FIG. 3 will be described.

  The power supply current value is measured when the liquid crystal driver is in a static state (also called a non-operating state). Here, static means that the signal is stopped by setting the input signals CK, RGB input, LS to VDD level or GND level, and the current that always flows in the analog circuit is cut off so that the liquid crystal driver does not operate. is there.

  The current generated by the liquid crystal driver in the static state is approximately equal to zero, but not zero. This is because a minute leak current is generated when the transistor constituting the liquid crystal driver is off.

  The leakage current in the static state is determined by the number and size of the off transistors. The leakage current increases as the number of transistors that are turned off increases or the size of the transistors that are turned off is smaller. For this reason, since the internal state, that is, the number of transistors that are turned off and the size of the transistors that are turned off vary depending on the state before the device enters a static state, the measurement current also varies.

  Furthermore, the leakage current of a transistor varies depending on factors such as slight non-uniformity in processing dimensions and small non-uniformity of impurities to be doped. If the device is different, the current value is different even if the internal state is the same. Therefore, an identifier can be generated based on the power supply current value for each internal state of various devices.

FIG. 6 is an example of a graph obtained by measuring and plotting the current values (IDD + ILS) of the power supply VDD and VLS supplied to a liquid crystal driver with 256-bit video signal output with 8-bit video signal data in the following 1024 states. The unit of the vertical axis is μA. Here, the 1024 state means
State 1) Static state when the liquid crystal driver starts to capture the video data from the RGB input. State 2) When the liquid crystal driver finishes capturing the video data from the RGB input, that is, after the video data is captured in all the sampling memories. Static state 3) During data transfer from sampling memory to hold memory. That is, the static state state at the start of changing the output state of the liquid crystal driver 4) the four static states of the static state in the state where the output state is stable after the output of the liquid crystal driver is started, and the input data (gradation) It is a 1024 state combining 256 ways. Hereinafter, the 1024 states determined by the above four static states and 256 patterns of input data (gradation) are referred to as internal states of the liquid crystal driver.

  The internal state of the liquid crystal driver is set by an apparatus (tester) that measures a semiconductor device. Since the tester can accurately control the timing of the input signal, the current measurement timing, etc., the internal transistor of the liquid crystal driver to be measured can be set to the same internal state for each measurement.

  FIG. 2 shows an embodiment of the present invention and is an explanatory diagram related to an identifier generation method. The upper part of FIG. 2A shows an example of a graph in which the power supply current value in the 1024 state of the liquid crystal driver in the wafer state is measured, and the unit of the vertical axis is μA. As shown in the lower part of FIG. 2A, for each of the measured power supply current values of 1024 states, as an internal state identification number (also referred to as a number) that is a number for identifying the internal state of the liquid crystal driver at the time of measurement. , 0011, 0012, 0013, 0014,.

  The number associated here is a number composed of a three-digit number indicating any gradation of the input data and a one-digit number indicating one of the static states. For example, 0011 represents the first state of one gradation, 0012 represents the second state of one gradation, 0013 represents the third state of one gradation, and 0014 represents the fourth state of the first gradation. Similarly, the second and subsequent gradations are associated as 0021, 0022, 0023, 0024,. For example, in the example shown in the lower part of FIG. 2A, 0011 = 0.822 μA, 0012 = 0.721 μA, 0013 = 0.799 μA, and 0014 = 0.824 μA.

  By measuring the power supply current values in the four static states at all the gradations, power supply current data indicating the power supply current values for 1024 states of 256 gradations × 4 states can be collected. The collected power supply current data may be used as an identifier, but in the present embodiment, an identification number list (0011, 0012, 0013, 0014, 0021, 0022,...) Indicating an internal identification number corresponding to the measured power supply current value. .., 2561, 2562, 2563, 2564) are used as identifiers. The measured power supply current values in the 1024 states are compared, and the power supply current values are in descending order (in the example shown in FIG. 2A, 1463 → 2273 → 2263 → 0862...) And the rearranged identification number list as the identifier of the semiconductor integrated circuit.

[Trace method using generated identifier]
This identifier hardly changes even if the temperature condition or the measurement condition changes depending on the wafer state or the individual package state (also called the individual state). For example, when the power source current value of the wafer state device measured at room temperature is 1.2 μA and the power source current value of the individual device is measured at high temperature, the characteristics of the semiconductor integrated circuit The current value is shifted to 2.4 μA corresponding to the temperature shift. In this embodiment, the measurement value itself is not used as an identifier, and the identification number list rearranged in a state with a large current value and a state with a small current value is used as an identifier, so that the influence of the measurement environment can be reduced.

  The upper part of FIG. 2B shows an example of a graph obtained by measuring the power supply current value in the 1024 state of the liquid crystal driver in the individual state, and the unit of the vertical axis is μA. As shown in the lower part of FIG. 2B, as with the identifier generation in the wafer state, the internal state identification numbers 0011, 0012, 0013, 0014,. , Respectively.

  For example, the power supply current value of the number 0011 in the wafer state shown in FIG. 2A is 0.822 μA, while the number 0011 in the individual state is shown in the lower part of FIG. The power supply current value is 0.832 μA. In all of the numbers 0012, 0013, and 0014, the power supply current value is shifted. As described above, the power supply current value of the liquid crystal device fluctuates due to changes in temperature conditions and measurement conditions. Therefore, when the power supply current value itself is used as an identifier, the individual state device and the wafer state device are linked. (Trace) may not be performed correctly.

  Therefore, by using this identifier created based on the magnitude relationship of current values as described below, it becomes possible to link a device in the individual state and a device in the wafer state.

  Specifically, the lower part of FIG. 2B shows an example of an identification number list in which the power supply current values in the 1024 states in the individual state are compared and rearranged in order of the power supply current values. . The wafer number identification number list shown in the lower part of FIG. 2A is 1463, 2273, 2263, 0862,... In order from the top, whereas the list shown in FIG. The one-state identification number list is in the order of 1463, 2273, 2263, 1011,. Similarly, the wafer state identification number list shown in FIG. 2 (a) is 2422, 2412, 1984, 1763,... In order from the bottom, whereas the individual state shown in FIG. The identification number list is in the order of 2422, 2103, 1984, 1763,.

  Although it is desirable that all the magnitude relations of the power supply current values corresponding to the respective internal state identification numbers match, in the example shown in FIGS. 2A and 2B, the measurement of the power supply current value in each state is performed. Since the value difference is a minimum value of about 0.001 μA, the magnitude relationship may be switched depending on the current measurement accuracy. In consideration of this point, the identifier of the wafer state and the identifier in the individual piece state are compared, and if the matching rate is equal to or higher than a predetermined threshold (for example, 85% or more), the individual state device and the wafer It can be tied to a device in the state and preferably allows tracing. The threshold value of the coincidence rate can be determined statistically by collecting the identifiers of the devices in the wafer state and the identifiers of the devices in the individual piece state.

  Therefore, according to the identifier generation method according to the present invention, it is possible to generate a highly reliable identifier.

  In the above embodiment, the case where an identifier is generated using all of the 1024 states has been described. However, the case where an identifier is generated using a part of the 1024 states will be described below.

  FIG. 7 shows an embodiment of the present invention, and is an explanatory diagram regarding a modification of the identifier generation method. The upper part of FIG. 7A shows an example of a graph in which the power supply current value in the 1024 state of the liquid crystal driver in the wafer state is measured in the same manner as the upper part of FIG. The unit is μA. For each of the measured power supply current values in the 1024 states, as an internal state identification number (also called a number) that is a number for identifying the internal state of the liquid crystal driver at the time of measurement, 0011, 0012, 0013, 0014,. Are associated with each other. As shown in the lower part of FIG. 7A, the power supply current values in the measured 1024 states are compared, and the identification number list is rearranged in descending order of the power supply current values. Further, as shown in the lower part of FIG. 7A, in the rearranged identification number list, the power supply current values from 1 to Nth (N is a natural number of 1024 or less) are large, similarly from 1 to N Create an identification number list that is rearranged in the state with the smallest power supply current value up to. An identifier of each semiconductor integrated circuit is generated based on the created identification number list.

  By using this identifier, it is possible to compare and associate the identifier in the wafer state with the identifier in the individual piece state.

  The number N used as an identifier can be determined by the matching rate. The match rate and the required value of N are calculated statistically by stacking the data. If the match rate is high, N can be set small.

  The specific value of N is not limited to the present embodiment, but for example, N = 30, N = 50, and the like can be taken as typical values.

  In Patent Document 1, for example, a liquid crystal driver is characterized by an output voltage value for each output terminal having several hundred to 1000 pins or more and a current value variation for each internal state, which are used as identifiers. In the method of Patent Document 1, the output voltage value for each output terminal having hundreds to 1000 pins or more used as each identifier is analyzed, and the amount of data is enormous for tracing, and it is necessary to analyze the enormous data. This can increase the time required for tracing.

  According to the identifier generation method of the present invention, since the power supply current value of the semiconductor integrated circuit is used as an identifier without increasing the chip area, the data collection time (test time reduction) is suppressed together with the data amount, and the high It can be traced with efficiency.

  In this embodiment, the variation of the power supply current value in the internal state of the 1024 states (256 gradations × 4 states) of the liquid crystal driver is used, but the power supply current values in various states of the internal circuit are used. Is also possible.

  For example, the 256 states in which 256 grayscale input data is input in the state 1 of the liquid crystal driver (the static state when the liquid crystal driver starts to capture the video data from the RGB input) are defined as internal states, and the power supply current in each state The value may be measured. A specific example will be described with reference to FIG.

  FIG. 8 shows an embodiment of the present invention and is an explanatory diagram regarding a modification of the identifier generation method. As shown in FIGS. 8A and 8B, power supply current data for 256 states of 256 gradations × 1 state is collected. The measured power supply current values in the 256 states are compared, the identification number list is rearranged in order of increasing or decreasing power supply current value, and the rearranged identification number list is used as the identifier of the semiconductor integrated circuit. In this case, since it is possible to save the trouble of setting each of the four states using a tester, the time required for measuring the power supply current value can be shortened.

  Further, identifiers may be generated based on an identification number list in which M (M is a natural number of 256 or less) in order of increasing power supply current value and M in order of decreasing power among the 256 states.

  The number M used as an identifier in this case can also be determined by the matching rate. The match rate and the required value of M are calculated statistically by stacking the data. If the match rate is high, M can be set small.

  In this case, the time required for tracing using the identifier generated by the above procedure can be further shortened.

  Further, instead of associating an internal state identification number with each of the measured power supply current values in the 1024 state, the power supply current value from the semiconductor integrated circuit placed under two predetermined conditions in the non-operating state The identification number may be associated with the difference. For example, the difference between the power supply current value when the input data of gradation 001 in state 1 is input and the power supply current value when the input data of gradation 001 in state 2 is input is obtained, and the identification number 0011 is associated. Similarly, the difference between the power supply current value in state 1 and the power supply current value in state 2 when the input data of each gradation is input is obtained, respectively, and identification numbers 0021, 0031,..., 2541, 2551, 2561 are sequentially assigned. Associate. The obtained 256 difference values may be compared to create an identification number list in which the identification numbers are rearranged in order of increasing or decreasing difference values, and this identification number list may be used as an identifier. Furthermore, among the rearranged identification number lists, L (L is a natural number of 256 or less) in the descending order of difference values and L identification number lists rearranged in the smaller order may be used as identifiers.

  The number L used as an identifier in this case can also be determined by the matching rate. The coincidence rate and the required L value are calculated statistically by stacking data. If the matching rate is high, L can be set small.

  In this case, since the identifier is generated based on the difference between the power supply current values in the two states, it is possible to generate a more reliable identifier.

  In the present embodiment, a four-digit number is used as the internal state identification number, but this does not limit the present invention. That is, it is only necessary to identify the internal state of the semiconductor integrated circuit in the non-operating state, and a character string and a combination of a number and a character string may be used. For example, by expressing a 3-digit number indicating input data of 256 gradations in hexadecimal and using 2 digits, the number of digits of the internal state identification number can be reduced, and the data amount of the identifier can be reduced. .

  In the above example, a liquid crystal driver has been described as an example of a semiconductor integrated circuit. However, the present invention is not limited to this and can be applied to a semiconductor integrated circuit other than a liquid crystal driver. It is.

  The above is the description of the identifier generation method for the semiconductor integrated circuit according to the present embodiment and the trace method using the generated identifier. Next, an identifier generation apparatus 1 according to the present invention used for actually using the identifier generation method will be described.

[Identifier generator 1]
FIG. 1 shows a block diagram of an identifier generating apparatus 1 according to the present embodiment. The identifier generation device 1 includes a DC measurement unit 11, a memory unit 12, a calculation unit 13, a comparison unit 14, and a power supply unit 15. The identifier generation device 1 is connected to the database 50, for example. In FIG. 1, the double line indicates the path of the power supply current, and the solid line indicates the path of the signal. First, an identifier assigning process for assigning an identifier to a liquid crystal driver (semiconductor integrated circuit) to be identified will be described along a specific signal flow.

  The power supply unit 15 is means for supplying power to the semiconductor integrated circuit to be identified.

  A tester for measuring a semiconductor device is connected to the liquid crystal driver to be identified. The tester is a means for setting the state of the liquid crystal driver. Specifically, the four static states described above are set.

  Further, the identifier generation device 1 includes an input signal supply unit (not shown). The input signal supply unit is means for supplying 256-gradation input data to a liquid crystal driver to be identified. In the four static states set by the tester, the input signal supply unit is controlled by the tester so that the input signal of 256 gradations is input to the liquid crystal driver. In this embodiment, 1024 internal states are set by the tester and the input signal supply unit.

  In this embodiment, the identifier generation device 1 includes an input signal supply unit, and a configuration in which input data is supplied from the input signal supply unit to the semiconductor integrated circuit will be described. However, this limits the present invention. It is not a thing. The input signal supply unit that supplies the input data may be included in the identifier generation device 1 or may be configured as included in another device.

  The DC measurement unit 11 is a means for measuring the power supply current supplied from the power supply unit 15 to the semiconductor integrated circuit. In particular, in the present embodiment, the DC measurement unit 11 measures a power supply current value for each of a plurality of internal states, and sequentially transmits the measured power supply current value to the memory unit 12. Further, the DC measurement unit 11 is controlled by the tester for the measurement timing of the power supply current value.

  The memory unit 12 is a means for accumulating the power supply current value for each of a plurality of internal states sent from the DC measurement unit 11 for each semiconductor integrated circuit.

  The arithmetic unit 13 is a means for generating an identifier based on power supply current values in a plurality of internal states for each semiconductor integrated circuit stored in the memory unit 12. Specifically, the arithmetic unit 13 has an internal state identification number 0011, 0012, 0013, 0014 which is a number for identifying the internal state of the liquid crystal driver for each of the 1024 state power supply current values measured by the DC measuring unit 11. , ... are associated with each other. Subsequently, the calculation unit 13 compares the power supply current values associated with the internal state identification numbers, rearranges the internal state identification numbers in order of increasing or decreasing power supply current values, and creates an identification number list. . Further, the calculation unit 13 selects the identification number list rearranged in a state where the power supply current values from 1 to Nth are large, similarly in a state where the power supply current value is small from 1 to Nth. create. The calculation unit 13 generates the created identification number list as an identifier of the semiconductor integrated circuit. The calculation unit 13 outputs the identifier generated for each semiconductor integrated circuit in this manner to the database 50.

  The database 50 is a means for associating identifiers input to each semiconductor integrated circuit with manufacturing histories, inspection histories and the like related to the semiconductor integrated circuits, and accumulating and managing the associated information.

  Specifically, the database 50 associates the input identifier with the manufacturing history and inspection history of the liquid crystal driver, and stores and manages the associated data for each liquid crystal driver.

  As described above, by using the identifier generation device 1 according to the present embodiment, a unique identifier can be generated for each liquid crystal driver. By using the identifier 50 together with the database 50, manufacturing information about individual semiconductor integrated circuits, Inspection information and the like can be accumulated and managed.

[Trace method using identifier generator 1]
On the other hand, the identifier discriminating step for specifying the manufacturing information or the inspection information of the liquid crystal driver in which a defect is found in the inspection step or the liquid crystal driver returned from the user can be performed as follows.

  First, it is assumed that the identifier of the liquid crystal driver in the wafer state is generated by the identifier generation device 1 and stored in the database 50 in advance. The liquid crystal driver in the individual state is set to the internal state of 1024 by the tester and the input signal supply unit, and transmits the power supply current value in each state to the DC measurement unit 11. The DC measurement unit 11 measures the power supply current value of the signal and sequentially outputs the measured value to the memory unit 12.

  The memory unit 12 stores the power supply current measurement value input from the DC measurement unit 11 for each liquid crystal driver. Based on the power supply current measurement value stored in the memory unit 12, the calculation unit 13 performs the same processing as that for generating an identifier in the wafer state, and generates an identifier for each liquid crystal driver. The generated identifier is input to the comparison unit 14.

  The comparison unit 14 compares the input identifier with the identifier for the same type of semiconductor integrated circuit stored in the database 50, and compares the input identifier with the identifier for the same type of semiconductor integrated circuit stored in the database 50. Among them, it is a means for identifying one of them.

  Specifically, the comparison unit 14 compares the input identifier with all identifiers for the same type of liquid crystal driver stored in the database 50, and compares the input identifier with the same type of liquid crystal stored in the database 50. Identify one of the driver identifiers.

  In the identification operation, any one of the identifiers stored in the database 50 and the input identifier are sorted, for example, in a state where the power supply current values from 1 to Nth in the sorted identification number list are large. Can be easily performed by sequentially comparing.

  In an ideal situation, the identifiers stored in the comparison unit 14 and the database 50 are compared with the input identifiers, and if the order of the internal state identification numbers in the identification number list all match, both identifiers are the same. Judged as an identifier.

  Actually, since the measurement of the power supply current value in the DC measurement unit 11 involves a measurement error, the identifier stored in the database 50 and the input identifier may not completely match. Identification with sufficient accuracy is possible. Specifically, the comparison unit 14 does not change the identifiers stored in the database 50 and the input identifiers even if there are several internal state identification numbers whose orders are different due to measurement errors. If the order of the internal state identification numbers matches, both identifiers may be identified as the same identifier, and the identification operation has a very high accuracy to the extent that there is no practical problem.

[Embodiment 2]
In the second embodiment of the present invention, the identifier is set based on the set of power supply current values of the semiconductor integrated circuit excluding values significantly different from other values caused by noise or poor contact. It is about the method of generating.

  FIG. 9 is a plot of the results of measuring the power supply current value of the liquid crystal driver while changing the gradation of the input data input to the liquid crystal driver. In addition, a plurality of graphs having different shades in FIG. 9 indicate power supply current values in four different static states. In FIG. 9, a portion surrounded by a circle indicates an abnormal value that is significantly different from the measurement values at other measurement points. The unit of the vertical axis in FIG. 9 is milliampere (mA).

  In general, the power supply current value of a semiconductor integrated circuit to be measured is not constant and is accompanied by a measurement error. Therefore, an identifier can be generated using the power supply current by sampling a specific power supply terminal a plurality of times for each device state.

  As shown in FIG. 9, in actual measurement, abnormal data is generated due to the influence of noise or poor contact of the measurement system.

  In the present embodiment, an identifier to be given to the semiconductor integrated circuit is generated based on a set of power supply current values excluding the abnormal data (that is, power supply current values far from power supply current values at other sampling points). . Here, the abnormal data can be regarded as a power supply current value having a large deviation from the power supply current value at another sampling point.

  By adopting such a method, in the present embodiment, it is possible to generate an identifier while suppressing the influence of abnormal data due to noise, poor contact, or the like.

  As described above, in the present embodiment, the identifier given to each of the plurality of semiconductor integrated circuits is set such that the power supply current value having a large deviation from the power supply current values in the plurality of internal states in which the semiconductor integrated circuit is not operating. An identification number list is created except for (abnormal data), and the created identification number list is used as an identifier.

  According to the above method, the identifier to be given to each of the plurality of semiconductor integrated circuits is changed from a power supply current value (abnormal data) having a large deviation from a power supply current value in a plurality of internal states in which the semiconductor integrated circuit is not operating. ), The identifier can be generated while suppressing the influence of an abnormal value of the power supply current caused by noise, poor contact, or the like.

  As a specific identifier generation method, the method described in the above embodiment may be used. Whether or not the data is abnormal data can be determined by, for example, determining that the difference from the average value of all the data is equal to or greater than a predetermined threshold. As the predetermined threshold, for example, the variance of all data may be used, or the standard deviation of all data may be used.

  Further, the present embodiment is not limited to the case where the identifier is generated based on a set obtained by removing abnormal data from the set of power supply current values of the semiconductor integrated circuit as described above.

  For example, in the present embodiment, the identifier given to each of the plurality of semiconductor integrated circuits is based on the difference between the power supply current values of the semiconductor integrated circuits placed under two predetermined conditions in the non-operating state. May be generated.

  According to the above method, the identifier given to each of the plurality of semiconductor integrated circuits is set to the difference between the power supply current values of the semiconductor integrated circuits placed under two predetermined conditions in the non-operating state. Therefore, it is possible to generate an identifier while suppressing the influence of an abnormal value of power supply current caused by noise, poor contact, or the like.

  In the above example, a liquid crystal driver has been described as an example of a semiconductor integrated circuit. However, the present invention is not limited to this and can be applied to a semiconductor integrated circuit other than a liquid crystal driver. It is.

(Summary)
An identifier generation method according to an aspect of the present invention is an identifier generation method for generating an identifier for identifying a plurality of semiconductor integrated circuits (liquid crystal drivers) having the same configuration from each other. An identifier to be assigned to each is generated based on power supply current values for a plurality of predetermined internal states in a non-operating state (static state) of the semiconductor integrated circuit.

  In general, each semiconductor element constituting a semiconductor integrated circuit is the same type of semiconductor element due to microscopic factors such as slight non-uniformity in processing dimensions and slight non-uniformity of doped impurities. But their characteristics are different from each other. Therefore, even in a semiconductor integrated circuit having the same configuration constituted by the same kind of semiconductor elements, the power supply current value under the same condition differs for each semiconductor integrated circuit.

  Further, the characteristics of the semiconductor elements constituting the semiconductor integrated circuit hardly change even if time elapses or the wafer state is cut out from the wafer state. Therefore, the power supply current value of a certain semiconductor integrated circuit hardly changes under the same conditions. Therefore, the power supply current value of the semiconductor integrated circuit can be used as an identifier unique to each semiconductor integrated circuit under the same conditions.

  Furthermore, according to the identifier generation method, the identifier is generated based on the power supply current values for a plurality of predetermined internal states in the non-operating state (static state) of the semiconductor integrated circuit. Can be generated.

  In the identifier generation method according to one aspect of the present invention, an internal state identification number (number) for mutually identifying the plurality of predetermined internal states is a power supply for the internal state corresponding to each internal state identification number. It is preferable to generate the identifier based on an identification number list obtained by rearranging according to the magnitude relationship of the current value.

  Generally, when measuring an analog signal value or power supply current output from a semiconductor integrated circuit, a measurement error is accompanied. Since the measurement error is contained in the generated identifier, if the influence of the measurement error is increased, the identity (reproducibility) of the generated identifier is impaired.

  The identifier given to each of the plurality of semiconductor integrated circuits, the internal state identification number given for each of the plurality of internal states in the non-operating state of the semiconductor integrated circuit, according to the power supply current value of each of the plurality of internal states Rearrange. By generating the identifiers of the individual semiconductor integrated circuits based on the rearranged identification number list, it is possible to reduce the influence of the measurement error, and therefore it is possible to generate more reliable identifiers.

  Furthermore, in the identifier generation method according to an aspect of the present invention, among the internal state identification numbers included in the identification number list, the top N (N is a natural number) internal state identification numbers corresponding to the larger power supply current values. It is preferable that the lower N internal state identification numbers having smaller power supply current values correspond to the identifiers.

  An identifier to be assigned to each of the plurality of semiconductor integrated circuits is extracted by extracting only the top N and the bottom N of the rearranged identification number list and using the identifiers of the individual semiconductor integrated circuits, thereby further reducing the number of identifiers. It is possible to generate a highly reliable identifier with the amount of data.

  In the identifier generation method according to one aspect of the present invention, the plurality of predetermined internal states are determined by a plurality of non-operation states and values of input data to the semiconductor integrated circuit, Among the plurality of non-operational states, an internal state identification number for mutually identifying an internal state defined by one non-operational state and the value of the input data is a power supply for the internal state corresponding to each internal state identification number. An identification number list is created by rearranging according to the magnitude relationship of the current value values, and among the internal state identification numbers included in the identification number list, the higher M corresponding power supply current values are larger (M is a natural number) ) And the corresponding lower M internal state identification numbers with smaller power supply current values are preferably used as the identifier.

  By reducing the plurality of internal states when measuring the power supply current value, the generation time for generating the identifier can be shortened. Further, by extracting only the upper M pieces and lower M pieces of the rearranged identification number list as identifiers to be assigned to each of the plurality of semiconductor integrated circuits, and using them as identifiers of individual semiconductor integrated circuits. In addition, a highly reliable identifier can be generated with a smaller amount of data.

  In the identifier generating method according to one aspect of the present invention, it is preferable that the identifier is generated based on a difference between power supply current values supplied to the semiconductor integrated circuit placed under two predetermined conditions.

  According to the above method, the identifier to be assigned to each of the plurality of semiconductor integrated circuits is generated based on a difference between power supply current values supplied to the semiconductor integrated circuits placed under two predetermined conditions. Therefore, it is possible to generate an identifier while suppressing the influence of an abnormal power supply current value caused by noise or poor contact.

  Further, in the identifier generation method according to one aspect of the present invention, an identifier to be given to each of the plurality of semiconductor integrated circuits is a power supply current value group for a plurality of predetermined internal states in a non-operating state of the semiconductor integrated circuit. From this, it is preferable to generate based on the power supply current value group excluding the power supply current value having a large deviation.

  Here, the power supply current value having a large deviation refers to, for example, a power supply current value that is more than a predetermined threshold from the average of other power supply current values.

  According to the above method, the identifier given to each of the plurality of semiconductor integrated circuits is a power supply current having a large deviation from a power supply current value group for a plurality of predetermined internal states in the non-operating state of the semiconductor integrated circuit. Since it can be generated based on the power supply current value group excluding the value, the identifier can be generated while suppressing the influence of the power supply current having an abnormal value caused by noise or poor contact. .

  Furthermore, in the identifier generation method according to one aspect of the present invention, the semiconductor integrated circuit is a liquid crystal driver, and the power supply current value is a power supply current value for a plurality of gradations in a non-operating state of the liquid crystal driver. Is preferred.

  The semiconductor integrated circuit trace method according to one aspect of the present invention is characterized in that the association between the wafer state of the semiconductor integrated circuit and the semiconductor integrated circuit piece state is associated using the identifier described above. Yes.

  By using the above-described trace method, an identifier can be generated using a function that has been provided in the past without using a new identifier circuit or process in the semiconductor integrated circuit, thereby suppressing an increase in manufacturing cost. be able to. In addition, the identifier can be identified even when there is a defect in a part of the semiconductor integrated circuit to be identified, such as a return from the user or a defective product, and the power supply current becomes high depending on the state. Therefore, it is possible to reliably trace the manufacturing history of the semiconductor integrated circuit.

  Furthermore, an identifier generation apparatus according to an aspect of the present invention is an identifier generation apparatus that generates an identifier for identifying a plurality of semiconductor integrated circuits having the same configuration from each other, and is provided in each of the plurality of semiconductor integrated circuits. It is characterized by comprising identifier generating means for generating an identifier to be assigned based on power supply current values for a plurality of predetermined internal states in a non-operating state of the semiconductor integrated circuit.

  According to said identifier production | generation apparatus, there exists an effect similar to said identifier production | generation method.

  Moreover, it is a program for operating the computer with which the identifier production | generation apparatus which concerns on 1 aspect of this invention is provided, Comprising: The program for functioning the said computer as each means with which the said identifier production | generation apparatus is provided, and these A computer-readable recording medium on which the program is recorded is also included in the scope of the present invention.

(Additional notes)
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

[Example of software implementation]
Finally, each block of the identifier generation device 1 may be realized by hardware by a logic circuit formed on an integrated circuit (IC chip) or by software using a CPU (Central Processing Unit). May be.

  In the latter case, the identifier generating device 1 includes a CPU that executes instructions of a program that realizes each function, a ROM (Read Only Memory) that stores the program, a RAM (Random Access Memory) that expands the program, the program, A storage device (recording medium) such as a memory for storing various data is provided. An object of the present invention is to provide a recording medium in which a program code (execution format program, intermediate code program, source program) of a control program of the identifier generation apparatus 1 which is software for realizing the above-described functions is recorded so as to be readable by a computer. This can also be achieved by supplying the identifier generation apparatus 1 and reading and executing the program code recorded on the recording medium by the computer (or CPU or MPU).

  As the recording medium, a non-transitory tangible medium such as a magnetic tape or a cassette tape, a magnetic disk such as a floppy (registered trademark) disk / hard disk, or a CD-ROM / MO Discs including optical discs such as / MD / DVD / CD-R, cards such as IC cards (including memory cards) / optical cards, semiconductor memories such as mask ROM / EPROM / EEPROM (registered trademark) / flash ROM Alternatively, logic circuits such as PLD (Programmable Logic Device) and FPGA (Field Programmable Gate Array) can be used.

  Further, the identifier generating device 1 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited as long as it can transmit the program code. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication network, and the like can be used. The transmission medium constituting the communication network may be any medium that can transmit the program code, and is not limited to a specific configuration or type. For example, even with wired lines such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, and ADSL (Asymmetric Digital Subscriber Line) line, infrared rays such as IrDA and remote control, Bluetooth (registered trademark), IEEE 802.11 wireless, HDR ( It can also be used by radio such as High Data Rate (NFC), Near Field Communication (NFC), Digital Living Network Alliance (DLNA), mobile phone network, satellite line, and digital terrestrial network. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  The identifier generation method according to the present invention can be suitably used for identifying a semiconductor integrated circuit.

DESCRIPTION OF SYMBOLS 1 Identifier production | generation apparatus 11 DC measurement part 12 Memory part 13 Calculation part 14 Comparison part 15 Power supply part

Claims (4)

An identifier generation method for generating an identifier for identifying a plurality of semiconductor integrated circuits having the same configuration from each other,
An identifier generating step for generating an identifier to be given to each of the plurality of semiconductor integrated circuits based on power supply current values for a plurality of predetermined internal states in a non-operating state of the semiconductor integrated circuit ;
In the identifier generating step, the internal state identification numbers for mutually identifying the plurality of predetermined internal states are rearranged according to the magnitude relationship of the power supply current values with respect to the internal states corresponding to the internal state identification numbers. Based on the obtained list of identification numbers, the identifier is generated.
An identifier generation method characterized by the above. The identifier generation method according to claim 1 ,
In the identifier generation step, among the internal state identification numbers included in the identification number list, the top N (N is a natural number) internal state identification numbers having a larger corresponding power supply current value, and the corresponding power supply current value An identifier generation method characterized in that the lower N internal state identification numbers having smaller values are used as the identifier. The identifier generation method according to claim 1 or 2 ,
The semiconductor integrated circuit is a liquid crystal driver,
The identifier generation method, wherein the power supply current value is a power supply current value for a plurality of gradations in a non-operating state of the liquid crystal driver. An identifier generation device for generating an identifier for identifying a plurality of semiconductor integrated circuits having the same configuration from each other,
An identifier to be assigned to each of the plurality of semiconductor integrated circuit provided with an identifier generating means for generating on the basis of the value of the supply current to a plurality of internal states predetermined in the non-operating state of the semiconductor integrated circuit,
The identifier generating means rearranges the internal state identification numbers for identifying the plurality of predetermined internal states according to the magnitude relationship of the power supply current values with respect to the internal states corresponding to the internal state identification numbers. Based on the obtained list of identification numbers, the identifier is generated.
An identifier generation device characterized by the above.

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