The content of the invention
The problem of present invention exists for prior art, propose a kind of direct current using integrated circuit test system to chipThe test process of parameter is realized to be calibrated to the DC measurement that is, PMU of integrated circuit test system, is existed parallel so as to realizeDC measurement on-line calibration device and method in the integrated circuit test system of line calibration.
To reach above-mentioned technical purpose, technical scheme provides DC measurement in a kind of integrated circuit test systemThe on-line calibration device of unit, it includes integrated circuit test system, stable measurand and external DC parameter to be calibratedMeasuring instrumentss, the integrated circuit test system is connected by pin and forms test loop between stable measurand, describedThe positive and negative terminal of external DC parameter measuring instrumentss connects the test lead of measurand by Kelvin.
The on-line calibration method of DC measurement, the integrated circuit test system in a kind of integrated circuit test systemThe on-line calibration method of middle DC measurement comprises the following steps：
S1, collection integrated circuit test system export DC parameter to stablizing when measurand carries out proper testing；
S2 while the voltage of the measurand in test is measured using external DC parameter measuring instrumentss, and withThe DC parameter that the testing process synchronous acquisition DC parameter measuring instrumentss measurement of integrated circuit test system obtains；
S3, the DC parameter that DC parameter measuring instrumentss measurement is obtained and integrated circuit test system are tested to the stabilizationThe related DC parameter of object setting is compared, and is realized according to comparative result to DC measurement list in integrated circuit test systemThe on-line calibration of member.
The on-line calibration system and method for DC measurement in integrated circuit test system of the present invention, it is based on existingDC parameter test program of some integrated circuit test systems to supported chip, by integrated circuit test system to stable negativeChip operation DC parameter test program is carried, and using external DC parameter measuring instrumentss to steady load chip in test processDC parameter compared with the related DC parameter that integrated circuit test system is set to the steady load chip, according to thanRelatively result realizes the on-line calibration to DC measurement in integrated circuit test system, that is, utilizes integrated circuit test system pairThe test process of the DC parameter of chip is realized to be calibrated to the parallel on-line of the DC measurement of integrated circuit test system, fromWithout separately designing calibration procedure, and DC parameter measuring instrument for each different integrated circuit test system to be calibratedTable is the DC parameter gathered in real simulation test process, therefore calibration data is more bonded practical operation application, and thenSo that calibration result is more accurate.
Embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, it is right below in conjunction with drawings and ExamplesThe present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, andIt is not used in the restriction present invention.
The present invention provides a kind of on-line calibration device of DC measurement in integrated circuit test system, and it includes treating schoolQuasi- integrated circuit test system 10, stable measurand 20 and external DC parameter measuring instrumentss 30, the integrated circuit are surveyedTest system 10 is connected by pin and forms test loop, the external DC parameter measuring instrumentss between stable measurand 20The connection corresponding with the test lead of measurand 20 of 30 positive and negative terminal.
It is specific as shown in figure 1, by the integrated circuit test system 10 by pin connect with stablize measurand 20 itBetween form test loop, and 20 each pin of measurand connected by Kelvin and draws and is connected to corresponding DC parameter and surveyInstrument 30 is measured, each DC parameter measuring instrumentss 30 are connected to control work station 40 by gateway 50, it is right by control work station 40The measured value of DC parameter measuring instrumentss 30 is monitored, wherein switching adapter 60 is realized different external dc parameter surveysAmount instrument 30 requires connect to corresponding pin according to measurement.Preferably, the DC parameter measuring instrumentss are ammeter or electricityPress table.
Wherein, the resistance value of the stable measurand 20 immobilizes, specifically, the stable measurand 20 needsMeet during the reperformance test of integrated circuit test system 10, its parameters index will not change, and avoidThe problems such as temperature drift, causes test result to change, and stable the deleting for measurand 20 selects mode as follows：Select multiple chipsAs measurand, retest is carried out to multiple chips respectively, the test result of each chip is recorded, filters out front and rear testAs a result consistent chip, after a period of time, retest is carried out to the chip that screening obtains again, and record the survey of each chipTest result, the filler test result chip consistent with last time test result, so as to which the chip is stablizes measurand 20, through excessiveSecondary experiment, the stable measurand 20 is preferably 54ls245 chips or 74ACT245 chips.
As shown in Fig. 2 Fig. 2 is to be entered using the on-line calibration device of DC measurement in said integrated circuit test systemThe FB(flow block) of row on-line calibration method, the on-line calibration method of DC measurement includes in the integrated circuit test systemFollowing steps：
S1, collection integrated circuit test system 10 export DC parameter to stablizing when measurand 20 carries out proper testing；Wherein, the resistance value of the stable measurand 20 immobilizes, specifically, the stable measurand 20 is preferably54ls245 chips or 74ACT245 chips；
S2 while the voltage of the measurand in test is measured using external DC parameter measuring instrumentss 30, andObtained DC parameter is measured with the testing process synchronous acquisition DC parameter measuring instrumentss 30 of integrated circuit test system 10；ItsIn, the DC parameter measuring instrumentss 30 are ammeter or voltmeter；
S3, the DC parameter that the measurement of DC parameter measuring instrumentss 30 is obtained and integrated circuit test system 10 are to the stabilizationThe related DC parameter that measurand 20 is set is compared, and is realized according to comparative result to direct current in integrated circuit test systemThe on-line calibration of measuring unit.
Specifically, test of the integrated circuit test system 10 to chip DC parameter is broadly divided into VIH/IIH (inputsHigh level voltage/electric current), VIL/IIL (input low level voltage/current), VOH/IOH (output high level voltage/electric current),VOL/IOL (output low level voltage/electric current).Wherein, VOH test process is as follows, and PMU applies IOH to the efferent duct of chipWhether pin, the output pin voltage of test chip are higher than expection setting value of the integrated circuit test system 10 to the output pin.VOL test process is that PMU applies whether IOL electric currents are less than to the output pin of chip, the output pin voltage of test chipExpection setting value of the integrated circuit test system 10 to the output pin.VIH/VIL test process is similar.IIH testJourney is that PMU driving incoming levels are high, measures the electric current of chip input pin.IIL test process is that PMU drives incoming levelFor it is low when measure chip input pin electric current.IOH/IOL test process is similar.As can be seen that integrated circuit test system10 DC parameter test process is broadly divided into two classes：One kind is to apply current measure voltage, such as VOH/VOL.One kind is to applyMaking alive measurement electric current such as IOH/IOL.
Specifically, as shown in figure 1, using 74ACT245 chips as measurand 20 is stablized, by 74ACT245 chip pipesPin connection corresponding with the passage of integrated circuit test system 10, and the input and output pin of 74ACT245 chips is passed through into KelvinConnect external voltage table, when test system applies electric current to 74ACT245 chip pins, by the reading of comparison voltage table andIntegrated circuit test system 10 measures obtained magnitude of voltage, can calibrate the voltage measurement of integrated circuit test system 10, pass throughThe current value that the resistance of magnitude of voltage divided by 74ACT245 chips obtains, pass through the current value applied with integrated circuit test system 10Comparing can be driven with the electric current of calibration test system.When integrated circuit test system 10 tests the voltage of application voltage tester electric currentDuring value, process is similar, by the input and output pin of Kelvin's connection 74ACT245 chips to voltmeter, according to the reading of voltmeterNumber calibrates the driving of the voltage of integrated circuit test system 10, voltage that voltmeter measurement is obtained divided by 74ACT245 chipsThe current value that resistance obtains, to calibrate the current measurement of integrated circuit test system 10.
As shown in figure 3, the on-line calibration method of DC measurement is also wrapped in integrated circuit test system of the present inventionInclude step S4；
S4, the direct current ginseng for obtaining the stable measurand 20 of a variety of resistances by the measurement of external DC parameter measuring instrumentss 30Compared with the related DC parameter that number is set respectively with integrated circuit test system 10 to it, realized according to comparative result to collectionThe gamut calibration of DC measurement current-voltage measurement into circuit test system 10.
Voltage mode is measured by the driving current of test system, the stable measurand 20 of a variety of resistances is set, makes driveDifferent DC parameters can be exported during dynamic identical current value, and then makes the voltage measurement amount of DC parameter coverage test systemJourney, realize the gamut calibration to voltage measurement.Meanwhile current-mode is measured by the driving voltage of test system, set moreThe stable measurand 20 of kind resistance, allows to export different current values during driving identical DC parameter, covers current valueThe current measurement range of lid test system, and then realize and the gamut of current measurement is calibrated.
Specifically, PMU voltages driving/measuring range of integrated circuit test system 10 is set as -2V~7V, resolution ratio 5mA,Electric current driving/measuring range is ± 10 μ A~40mA.Choose the driving current of integrated circuit test system 10 measurement voltage tester sideThe stable measurand 20 of magnitude of voltage configuration of formula, set the VOH test conditions of stable measurand 20 steady for driving 5mA, configurationThe resistance for determining measurand 20 is respectively 1 ohm, 10 ohm, 100 ohm, 1 kilohm, 1.4 kilohms, works as integrated circuit testingWhen system 10 drives 5mA electric currents, voltage should be respectively 5mV, 50mV, 500mV, 5V, 7V at the pin of stable measurand 20, lead toCross the reading for comparing external perimysium reference voltmeter and magnitude of voltage that test system measurement obtains can be surveyed with the voltage of calibration test systemAmount, in order to put forward high-tension coverage, can improve the quantity of measuring resistance and change the resistance of measuring resistance, be not used toLimit the present invention.It is adjustable -2V voltages using identical principle when setting drives negative voltage.
Likewise, the magnitude of voltage configuration as chosen the driving voltage of integrated circuit test system 10 measurement testing current mode is steadyDetermine measurand 20, the IOH test conditions for setting stable measurand 20 are driving 5V, configure the resistance of stable measurand 20Respectively 125 ohm, 1.25 kilohms, 12.5 kilohms, 125 kilohms, 500 kilohms, when integrated circuit test system 10When driving 5V voltages, electric current should be respectively 40mA, 4mA, 400 μ A, 40 μ A, 10 μ A at the pin of stable measurand 20.In order toThe coverage of electric current is improved, the quantity of measuring resistance can be improved and change the resistance of measuring resistance, is not used to limit thisInvention.It is the μ of adjustable -10 A~-40mA electric currents using identical principle when setting drives negative voltage.
The on-line calibration system and method for DC measurement in integrated circuit test system of the present invention, it is based on existingDC parameter test program of some integrated circuit test systems 10 to supported chip, by integrated circuit test system 10 to steadyFixed load chip runs DC parameter test program, and using external DC parameter measuring instrumentss 30 to stable negative in test processThe DC parameter for carrying chip compares to the related DC parameter that integrated circuit test system 10 is set to the steady load chipCompared with being realized according to comparative result to the on-line calibration of DC measurement in integrated circuit test system, that is, utilize integrated circuitTest system 10 is realized to the DC measurement of integrated circuit test system 10 to the test process of the DC parameter of chipParallel on-line is calibrated, without separately designing calibration journey for each different integrated circuit test system to be calibrated 10Sequence, and DC parameter measuring instrumentss 30 are the DC parameters gathered in real simulation test process, therefore calibration data is morePractical operation application is bonded, and then make it that calibration result is more accurate.Meanwhile in order to cover direct current in integrated circuit test systemThe calibration of current parameters in parameter, also DC parameter measuring instrumentss 30 can be replaced by by ammeter based on structure shown in Fig. 1, usedSame flow and mode, realizes the calibration to current parameters in DC parameter in integrated circuit test system.
The embodiment of present invention described above, is not intended to limit the scope of the present invention..Any basisThe various other corresponding changes and deformation that the technical concept of the present invention is made, should be included in the guarantor of the claims in the present inventionIn the range of shield.