JP2012118002A - Device tester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device tester capable of easily obtaining an overall trend of shmoo data of a plurality of DUTs without acquiring shmoo data, including data obtained in the past, again.SOLUTION: A device tester 100 for performing an electrical test of a device to be tested (DUT140) comprises: a shmoo acquisition part 220 for obtaining shmoo data of the device to be tested; a data storage part 222 for storing the obtained shmoo data in a file; a data reading part 228 for reading shmoo data from the file; a data selection part 226 for causing a user to select one, or two or more shmoo data items from shmoo data read from the obtained shmoo data and the file; and a superimposition display part 230 for logically calculating the selected one, or two or more shmoo data items by a plot unit, and displaying the calculated superimposition shmoo data on a display 212.

Description

  The present invention relates to a device tester capable of browsing shmoo data using a shmoo tool.

  In recent years, integrated circuits (ICs) have been increased in capacity, speed, and size (high density). In a device having such an integrated circuit, a high-speed and complicated process is required for electrical function testing as the density of the integrated circuit increases. In a device tester that performs such an electrical function test, a function test such as an access time margin is performed on a device under test (hereinafter referred to as “DUT”), for example, various microcomputers and memories. Yes.

  In the device tester, it is possible to execute a shmoo (see, for example, Patent Document 1) for deriving the electrical characteristics of the DUT by changing test parameters such as voltage and input / output timing set in the DUT. The device tester is equipped not only with a single DUT but also with a multi-shmoo function that tests a plurality of DUTs together and independently derives the electrical characteristics of each DUT. The user can visually grasp the characteristics of the DUT by using a shmoo tool that graphically selects and displays the shmoo data that is the result data of the shmoo.

  In addition, the applicant has proposed a technique for simultaneously testing a plurality of shmoo data by testing a plurality of DUTs together and displaying a plurality of shmoo data at the same time by previewing or overlaying them (patent). Reference 2). As a result, it becomes possible to simultaneously display and compare the shmoo data of a plurality of DUTs tested together using the multi shmoo function described above, so that it is easy to grasp the overall tendency of the shmoo data of a plurality of DUTs. As a result, the analysis time with the shmoo tool was reduced, and the device test efficiency was improved.

JP 2003-315418 A JP 2008-145157 A

  However, with the technique of Patent Document 2, although a plurality of shmoo data tested together can be displayed at the same time, it is not possible to display the plurality of shmoo data and the shmoo data acquired at the time of past shmoo at the same time. Can not. Therefore, when it is desired to display and compare them at the same time, it is necessary to perform another shmoo operation on the DUT from which the shmoo data has been acquired in the past and acquire the shmoo data again. For this reason, in the device tester of Patent Document 2, it is difficult to compare with the previously obtained shmoo data, and there is room for further improvement in improving the device test efficiency.

  In view of such a problem, the present invention provides a device tester that can easily grasp the overall tendency of shmoo data of a plurality of DUTs without acquiring shmoo data again, including data acquired in the past. It is intended to provide.

  In order to solve the above problems, a representative configuration of a device tester according to the present invention is a device tester that performs an electrical test of a device under test, and includes a shmoo acquisition unit that acquires shmoo data of the device under test. A data storage unit for storing the acquired shmoo data in a file, a data reading unit for reading the shmoo data from the file, and one or more shmoo data from the acquired shmoo data and the shmoo data read from the file A data selection unit that allows the user to select, and a superimposed display unit that logically calculates the selected one or more of the shmoo data in plot units and displays the calculated superimposed shmoo data on the display unit. It is characterized by that.

  According to the above configuration, the acquired shmoo data is stored in a file by the data storage unit, and the stored file can be read out by the data reading unit. Then, the superimposed display unit displays superimposed shmoo data obtained by logically calculating the acquired shmoo data (newly acquired shmoo data) and the shmoo data read from the file (previously acquired shmoo data). Displayed in the section. Accordingly, it is possible to compare the previously acquired shmoo data with the newly acquired shmoo data without performing measurement again on the DUT for which the shmoo data has been acquired in the past. As a result, it becomes easy to grasp the overall tendency of the shmoo data, and the analysis time and thus the device test efficiency can be further improved.

  The data selection unit may be capable of designating a plurality of files and selecting a part of the plurality of shmoo data included in each file. According to such a configuration, the shmoo data stored in a plurality of files and the newly acquired shmoo data can be compared in any combination. Even if the specified file includes a plurality of shmoo data, the user can select any shmoo data from among them. For this reason, a user's convenience can be improved.

  The superimposition display unit can set a color for each plot value, and when the plot values are different among a plurality of shmoo data, an intermediate color set for each value may be displayed. This makes it possible to visually recognize a difference in plot values between a plurality of shmoo data displayed simultaneously. Therefore, it becomes easy to grasp the overall tendency of the shmoo data and the difference between the shmoo data. Further, when different values exist in the plot, by using an intermediate color, it is only necessary to set a color for each value such as pass / fail, and the setting items can be reduced for convenience in use.

  According to the present invention, it is possible to provide a device tester that can easily grasp the overall tendency of shmoo data of a plurality of DUTs, including data acquired in the past, without acquiring shmoo data again. It becomes.

It is the schematic which shows the structure of the device tester concerning this embodiment. It is the functional block diagram which showed the hardware constitutions of the device tester. It is the flowchart which showed the flow of the device test method using the device tester concerning this embodiment. It is a figure which shows the user interface of a shmoo tool. It is a figure which shows the user interface of a shmoo tool. It is a figure which illustrates the past data list.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  After setting the DUT, the device tester according to the embodiment of the present invention applies a test signal to the DUT according to a pattern program in which the test order is written, and acquires a signal output from the DUT accordingly. In addition, the shmoo tool provided in the device tester derives the electrical characteristics of the DUT by changing test parameters such as voltage and input / output timing set in the DUT. In order to facilitate understanding regarding such DUT testing, the overall structure of the device tester will be described first.

  FIG. 1 is a schematic diagram illustrating a configuration of a device tester 100 according to the present embodiment. A device tester 100 shown in FIG. 1 is a tester that performs an electrical test of a device under test (DUT 140), and includes a main body 110 and a test head 120. The main body 110 is provided with a central control unit 114 that executes a test process preset by a user. The central control unit 114 can be operated by a user via a user interface 112 (which can be realized using a general-purpose computer) having a display unit 212 and an operation unit 214 described later. The test head 120 is also referred to as a relay card 122 (PE (Pin Electronics) card) including a test terminal connected to each device terminal of the DUT 140 and a pin module (both not shown) connected to the test terminal and executing a test function. .) Is provided. The relay card 122 reflects the command regarding the function test from the main body 110 on the test terminal of the DUT 140.

  A performance board 130 is mounted on the test head 120, and a DUT 140 is attached on the performance board 130. The performance board 130 has a structure that can be attached to the test head 120 and to which the DUT 140 can be attached.

  In the present embodiment, the central control unit 114 applies a test signal to the DUT 140 via the relay card 122 and captures a signal from the DUT 140. At this time, the device tester 100 determines whether or not the test target DUT 140 outputs a desired voltage at a desired timing (pass / fail).

  The allowable range for passing the DUT 140 must be within a range where it can be determined that the DUT 140 is operating normally. However, since various electrical elements within the DUT 140 are complicatedly affected, the range is calculated. It is difficult to decide unambiguously. Therefore, using the shmoo tool according to the present embodiment, the electrical characteristics of the plurality of DUTs 140 are extracted to derive appropriate test parameters, and whether or not the determination based on such test parameters is appropriately performed. Check.

  FIG. 2 is a functional block diagram showing the hardware configuration of the device tester 100. The central control unit 114 includes an integrated circuit such as a CPU, and manages and controls the entire device tester 100. Further, input / output of test signals to / from the DUT 140 of the relay card 122 is controlled in accordance with a test program for test execution. Furthermore, it is possible to execute a shmoo that derives the electrical characteristics of the DUT 140 by changing test parameters such as voltage and input / output timing set in the DUT 140. Details of each unit included in the central control unit 114 will be described later.

  The display unit 212 includes a color or monochrome display, and can check the test result of the device test and the shmoo data graphically via the user interface of the shmoo tool. The operation unit 214 includes switches such as a mouse, a keyboard, a cross key, and a joystick, and accepts user operation inputs.

  The tester memory 216 is configured by a RAM or the like, and temporarily stores shmoo data acquired by executing shmoo. The storage unit 218 includes a flash memory, an HDD (Hard Disk Drive), and the like, and stores the acquired shmoo data semipermanently. In the present embodiment, the storage unit 218 is not necessarily provided in the device tester 100, but the storage unit 218 is not limited to this, and is a separate storage from the device tester 100 such as a CD-ROM or USB memory. It may be a medium.

  The configuration of the central control unit 114 and the device test method will be described with reference to FIGS. FIG. 3 is a flowchart showing a flow of a device test method using the device tester 100 according to the present embodiment.

  As shown in FIG. 3, when a new test of the DUT 140 is performed using the device tester 100 (YES in step 402), the device tester 100 first sets test parameters from the operation unit 214 using a shmoo tool. (Step 404). The device tester 100 tests the DUT 140 in response to a shmoo start signal from the user, and the shmoo acquisition unit 220 executes shmoo and acquires the shmoo data of the DUT 140 (step 406).

  Shmoo is a program that examines how the pass / fail is affected by sequentially changing the determination range in order to determine the validity of the input / output of the DUT 140. Shmoo can be defined by either the input signal or the output signal of the DUT 140. The acquired shmoo data is used as reference data for determining an appropriate range under such plot observation and determining the test range during mass production.

  FIG. 4 is a diagram showing a user interface 300 of the shmoo tool, and particularly illustrates a user interface when one shmoo data is plotted. The shmoo tool is processed by the central control unit 114, and the user interface 300 displays the shmoo data. The user interface 300 is provided with a display DUT box 302 for designating the DUT 140 to be displayed, and a main area 304 that graphically represents the shmoo data of the DUT 140. When, for example, “2” is entered in the display DUT box 302, the shmoo data of the DUT 140 with “2” as the device number is displayed in the main area 304.

  In the example of FIG. 4, the shmoo tool automatically changes the voltage parameter and the timing parameter, and it is checked whether or not an actual voltage is present within the range indicated by the parameter (pass / fail). Specifically, it is inspected whether the output voltage detected after a predetermined range (STB0) 0 to 320 nsec from a predetermined input signal to DUT 140 is within an allowable range. For example, in the DUT 140 with the device number “2”, since the output of the DUT at the time of 176 nsec delay from the predetermined input signal is within the allowable range, the plot 306 of STB0 = 176 nsec and VOH = 3 V becomes “pass”. ing. Thus, the shmoo data is formed by arranging a plurality of cells as a plot in a grid pattern, and the passed plot and the failed plot are represented by different colors.

  As an order of measurement, for example, an appropriate voltage is selected from the upper limit (VOH) of the range, and the output signal is measured by sequentially shifting STB0 in the voltage range. When the STB0 shift is completed, the upper limit (VOH) of the range is changed, and the STB0 shift is repeated from the beginning.

  The shmoo data acquired as described above is stored in the tester memory 216 (step 408). Steps 406 to 408 are repeated until all the shmoo data is acquired (NO in step 410). When the acquisition of all the shmoo data is completed (YES in step 410), when the acquired shmoo data is stored (YES in step 412), the data storage unit 222 stores the shmoo data stored in the tester memory 216. Is stored in a file stored in the storage unit 218 (step 414).

  FIG. 5 is a diagram illustrating a user interface 300 of the shmoo tool, and particularly illustrates the user interface 300 when a plurality of shmoo data is plotted. In order to facilitate understanding, in the following description, the shmoo data acquired in the test in step 406 and stored in the tester memory 216 in step 408 is referred to as “new shmoo data”.

  Subsequently, when a plurality of plot tabs 300a shown in FIG. 5 is selected by user input via the operation unit 214, the new data list display unit 224 lists the new shmoo data stored in the tester memory 216 and creates a new The shmoo data list is displayed in the new list area 310 of the user interface 300 (step 416). Particularly in the present embodiment, the new data list display unit 224 reads out the new shmoo data displayed in the new list area 310 and generates shmoo data (plot image). Each of the shmoo data is reduced and displayed as thumbnails 312 side by side. Thus, when the user selects the shmoo data, not only the data name but also the shape of the shmoo data can be referred to as a preview, and the desired shmoo data can be quickly identified.

  In the present embodiment, the thumbnails (preview images) of the new shmoo data are displayed. However, the present invention is not limited to this, and only the data names (DUT numbers, etc.) may be displayed. In step 416, the new data list display unit 224 does not necessarily need to list the new shmoo data. If the data name of the new shmoo data is held in the shmoo acquisition unit 220, the shmoo acquisition unit 220 is stored. The data names may be sent as a list to the new data list display unit 224.

  When the new shmoo data list is displayed in the new list area 310, the data selection unit 226 causes the user to select new shmoo data via the operation unit 214 (step 418). As for the selection method, by operating the operation unit 214, the pointer is placed on the icon 312 to be selected, and the icon is dragged and dropped onto the selection list area 340 or the plot area 360 of the overlapping area 305, or the icon is double-clicked. It is possible to set arbitrarily. The new shmoo data selected in step 418 is reflected in the selection list area 340.

  Next, the new shmoo data selected in step 418 and the shmoo data stored in the file stored in the storage unit 218, that is, past acquired shmoo data (hereinafter referred to as past shmoo data). When reading past shmoo data (YES in step 420), such as when comparing past shmoo data (NO in step 402), the data reading unit 228 is first stored in the storage unit 218. And the folder list is displayed in the folder list area 320 (step 422). Subsequently, when an arbitrary folder is selected from the displayed folder list by a user input via the operation unit 214, the data reading unit 228 reads a file stored in the folder, and stores the file list in the file list. The data is displayed in the list area 330 (step 424).

  When the file list is displayed in step 424, the data selection unit 226 causes the user to select an arbitrary file by the operation unit 214, and if there is only one past shmoo data stored in the selected file (step 424). The data selection unit 226 determines that the past shmoo data stored in the file has been selected and reflects it in the selection list area 340 in the overlap area 305 (step 430).

  In step 426, the data selection unit can select (specify) a plurality of files. Thereby, the past shmoo data stored in a plurality of files and the new shmoo data can be arbitrarily combined and compared. Also in the file selection in step 426, an arbitrary operation such as a drag drop can be set as in step 418 described above.

  FIG. 6 is a diagram illustrating a past data list. If a plurality of past shmoo data is stored in the selected file (YES in step 426), the data reading unit 228 reads a plurality of past shmoo data stored in the file and displays a past data list. (Step 428). In this embodiment, as shown in FIG. 6, the past data list is displayed as a dialog 350 different from the user interface 300 in step 428. Then, the data selection unit 226 causes the user to select past shmoo data via the operation unit 214 (step 430). The past shmoo data selected in step 430 is reflected in the selection list area 340.

  As a selection method in the dialog 350 described above, by operating the operation unit 214, the check box 354 is checked by placing the pointer on the check box 354 provided below the number 352 of past shmoo data and clicking. To select (ON). Clicking on the checked check box 354 again releases the check (off). FIG. 6 illustrates a state where the past shmoo data of numbers “1”, “2”, “3”, and “5” is being checked (selected). In this way, by checking the check box 354, it is possible to select a part of the plurality of shmoo data included in the file, so that the selected (designated) file includes a plurality of shmoo data. However, the user can select any shmoo data from among them, and the convenience of the user can be improved.

  In the present embodiment, the past data list is displayed as the dialog 350. However, the present invention is not limited to this. The display is provided with a display area on the user interface 300 as in the case of displaying the folder list and the file list. Alternatively, other modes may be adopted. The above-described configuration is also merely an example in the display format and selection method of the dialog 350. For example, the past shmoo data names are displayed in a list instead of the check box 354, and the past shmoo data names are double-clicked or drag-dropped. It is good also as a structure selected by doing.

  If the selection of the shmoo data is not completed through steps 418 and 430 (NO in step 432), steps 418 to 430 are repeated until the selection is completed. When the selection of the shmoo data is completed (YES in step 432), a list of selected new shmoo data and past shmoo data is displayed in the selection list area 340.

  As described above, in this embodiment, the data selection unit 226 includes a plurality of shmoo data from new shmoo data (newly obtained shmoo data) and past shmoo data (shmoo data read from a file). Can be selected by the user. Therefore, it is possible to compare the shmoo data with the newly acquired shmoo data without performing measurement again on the DUT 140 that has acquired the shmoo data in the past.

  In the present embodiment, a check box 344 is provided for each shmoo data 342 displayed in the selection list area 340 as well. As a result, the user can switch on / off the check by operating the operation unit 214 as described above. For example, the user can improve the convenience of operation by temporarily excluding some of the selected data. be able to.

  When the selection of the shmoo data is completed in step 432, the superimposition display unit 230 displays the shmoo data selected by the data selection unit 226, in other words, in the selection list area 340 and is checked. The data is logically calculated in plot units (step 434), and the calculated superimposed shmoo data is displayed in the plot area 360 (display unit 212) in the superimposed area 305 (step 436).

  In the present embodiment, the superimposition display unit 230 can set a color for each plot value, and if the plot values differ among a plurality of superimposed shmoo data, an intermediate color set for each value is displayed. indicate. This makes it possible to visually recognize differences in plot values between multiple shmoo data displayed at the same time, making it easy to understand the overall trend of shmoo data and the differences between the shmoo data. Become. In addition, when different values exist in the plot, by using an intermediate color, it is only necessary to set a color for each value such as pass / fail, and the number of setting items can be reduced for convenience in use.

  As a specific example, if the pass is set to blue and the fail is set to red, the pass and fail can be recognized at a glance. When a plurality of data are superimposed in such a setting, if the plot values differ between the plurality of shmoo data, the plot is displayed in purple, which is an intermediate color between red and blue. Since the drawing is monochrome, in FIG. 5, among the superimposed shmoo data displayed in the plot area 360, the path (blue) plot 362 a is filled in, and the fail (red) plot 362 b is hatched, and different values are superimposed. (Purple) plot 362c is shaded.

  The intermediate color may be a single intermediate color (50%: 50%), but may be an intermediate color according to the ratio of the number of values when three or more shmoo data are superimposed. For example, when the pass is overlapped once and the fail is overlapped three times, the intermediate color can be displayed with pass color: failure color = 25%: 75%.

  As described above, after the superimposed shmoo data is displayed in step 436, when a new test of DUT 140 is performed again, or when the shmoo data is compared, that is, when it is not finished (NO in step 438), step Returning to 402, the subsequent steps are repeated.

  As described above, according to the device tester 100 according to the present embodiment, the data storage unit 222 and the data reading unit 228 can store and read the shmoo data acquired by the shmoo acquisition unit 220. For this reason, the superimposed display unit 230 can display the newly obtained new shmoo data and the superimposed shmoo data obtained by logically calculating the past shmoo data read from the file. As a result, since it is possible to compare past shmoo data with new shmoo data without performing measurement again on the DUT 140 for which shmoo data has been acquired in the past, the overall trend of those shmoo data can be compared. This makes it easier to grasp and can reduce the analysis time and further improve the device test efficiency.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood. Each process in the device test method of the present specification does not necessarily have to be processed in time series in the order described in the flowchart, and may include processes in parallel or by a subroutine.

  INDUSTRIAL APPLICABILITY The present invention can be used for a device tester that can browse shmoo data using a shmoo tool.

DESCRIPTION OF SYMBOLS 100 ... Device tester, 110 ... Main body, 112 ... User interface, 114 ... Central control part, 120 ... Test head, 122 ... Relay card, 130 ... Performance board, 140 ... DUT, 212 ... Display part, 214 ... Operation part, 216 ... Tester memory, 218 ... Storage unit, 220 ... Shmoo acquisition unit, 222 ... Data storage unit, 224 ... New data list display unit, 226 ... Data selection unit, 228 ... Data reading unit, 230 ... Superimposed display unit, 300 ... User Interface 302 ... Display DUT box 304 ... Main area 305 ... Superimposition area 310 ... New list area 312 ... Icon 320 ... Folder list area 330 ... File list area 340 ... Selection list area 342 ... Shmoo Data, 344 ... Check box Vinegar, 350 ... dialog, 352 ... number, 354 ... check box, 360 ... the plot area, 362a ... plot, 362b ... plot, 362c ... plot

Claims (3)

A device tester for conducting an electrical test of a device under test,
A shmoo acquisition unit for acquiring shmoo data of the device under test;
A data storage unit for storing the acquired shmoo data in a file;
A data reading unit for reading shmoo data from a file;
A data selection unit that allows the user to select one or more shmoo data from the acquired shmoo data and the shmoo data read from the file;
A superimposed display unit that logically calculates the selected one or two or more shmoo data in plot units, and displays the calculated superimposed shmoo data on a display unit;
A device tester comprising:   The device tester according to claim 1, wherein the data selection unit can designate a plurality of files and can select a part of the plurality of shmoo data included in each file.   The superimposition display unit can set a color for each plot value, and when the plot values are different among a plurality of shmoo data, it displays an intermediate color set for each value. The device tester according to claim 1.

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