JPH02183179A - Checking apparatus of integrated circuit - Google Patents

Abstract

PURPOSE:To quickly measure the voltage of a pad with high accuracy by providing a secondary electron signal detecting device having a filter capable of voltage control in order to detect a secondary electron signal of said measuring pad concentrated within a vacuum sector. CONSTITUTION:An input/output pin 25 of an IC 24 to be checked which is placed on the surface 13a at the air side of a substrate 13 is electrically connected to a measuring pad 21 collected on the surface 13b at the side of a vacuum sector of the substrate. This checking apparatus further includes a detecting means 30 equipped with a filter 31 to which a predetermined voltage is applied so as to detect the strength of a secondary electron signal and, an analyzing voltage generator 32 which controls the voltage to be applied to the filter 31, and the like. An electron beam 23 is irradiated selectively to the pad 21 by 11. A secondary electron generated at the pad 21 is detected by the detecting means 30 with an analyzing voltage preliminarily applied by 32 to the filter 31, which is determined as the signal strength by a secondary electron detecting circuit 33. In comparing this signal strength with a predetermined characteristic function of the pad 21 stored by a parameter table 43, the voltage of the pad can be measured considerably quickly and with high accuracy.

Description

[Detailed Description of the Invention] (Summary) The present invention relates to an integrated circuit testing device, and aims to shorten the time required for testing by measuring the output voltage of a human output bin with high accuracy, high speed, and high efficiency. A vacuum section, a mounting section for integrated circuits to be tested provided on the atmospheric section side surface of a partition forming a part of the vacuum section, and a plurality of integrated circuits to be tested placed on the mounting section. a plurality of measurement pads connected to each of the input/output bins by signal lines and exposed to the inner surface of the vacuum section of the bulkhead; A beam irradiation means for irradiating the measurement pad with an electron beam and a secondary electron signal intensity detection means generated from the measurement pad by the irradiation of the beam are provided in the vacuum part. In addition, it is installed alongside the vacuum section,
A beam deflection means for scanning an electron beam to selectively irradiate a predetermined measurement pad; a voltage control means for applying a predetermined voltage to a filter means forming a part of the secondary electron signal detection means; a storage means for measuring and storing in advance the relationship between the secondary electron signal intensity and the measurement pad voltage with respect to the voltage; and means for calculating the voltage of the measurement pad by referring to the relationship between the secondary electron signal intensity value and the pad voltage stored in the storage means.

[Industrial application field]

The present invention relates to an apparatus for measuring signal voltages of input/output bins of all types of ICs including LSIs, that is, integrated circuits, using an electron beam, and testing whether or not there is an abnormality in the internal circuits of the integrated circuits to be tested. In particular, the present invention relates to an integrated circuit testing device that can perform such testing at high speed and with high efficiency.

[Conventional technology]

An integrated circuit, more specifically a semiconductor integrated circuit (IC), has a large number of input/output bins arranged around its main body, each of which operates according to a certain built-in logic. Semiconductor integrated circuit (hereinafter simply IC)
When an IC is manufactured, it is necessary to inspect whether each input/output bin is operating according to the designed logic, and to improve the reliability of the manufactured IC.
It is common practice to perform a complete check.

However, since such tests involve a huge number of ICs to be tested, it is necessary to perform highly accurate measurements quickly in a very short period of time, and to shorten the number of man-hours required for testing and perform it with high efficiency. That is required.

Conventionally, testing of such ICs, for example, involves inserting the IC to be tested into a board that has a signal input/output wiring pattern, and connecting the input/output bins or leads of the IC to be tested to the wiring pattern. Then, after activating the vacuum pump to make the chamber a vacuum, a signal is applied to the IC to be tested via the wiring pattern, and during that time the electronics installed in the vacuum chamber are Depending on the gun, the IC
This was done by scanning the input/output bins or leads of the beam and observing the voltage at the input/output bins or leads that were illuminated by the beam at the time. However, in the method described above, (1) the IC is in an operating state during the test and generates heat during the test; The heat generated by the IC itself affects the test results. This is especially true if the IC is rated for high power consumption. Therefore, it is necessary to cool the IC, but since the IC is set in a vacuum, it is difficult to cool it.

■ Since the vacuum chamber is opened each time the IC to be tested is changed, it is necessary to operate the vacuum pump to evacuate the chamber after setting the new IC.
It is necessary to wait several minutes after setting C before starting the test, which requires a large number of testing steps.

■ The range in which the leads are dispersed is wider than the scanning range of the electron beam, and it is not possible to scan all the leads at once.
It is necessary to send C, etc. on an X-Y stage, which requires a large number of testing steps.

Furthermore, such conventional testing methods are unsuitable for ICs rated for particularly high power consumption, and have poor testing efficiency.

In order to solve this problem, the applicant of the present invention has proposed an IC inspection device as shown in FIG. (See patent application No. 16579/1983).

That is, in this inspection device, an IC or the like 24 to be inspected is installed on the atmospheric side 13a of the substrate 13, which functions as a partition wall that separates the vacuum section 14 and the atmospheric section 15, and the individual input/output bins 25 of this IC, etc. and the substrate are installed. Measuring pads 21 electrically connected through the substrate are concentratedly arranged on the surface 13b exposed to the vacuum side of the substrate, and the measuring pads are irradiated with an electron beam by a beam irradiator 11 provided in the vacuum area. 23 to detect the secondary electron energy emitted from the measurement pad, convert it into voltage by appropriate means, and measure the voltage signal of the input/output bin connected to the measurement pad. be.

However, even when such a device is used, measuring the voltage at the measurement pad must be completed in an extremely short time, and conventional voltage measurement methods using electron beams are unable to do so. The following problems still exist. That is, the conventional method of measuring voltage of a measurement pad utilizes the fact that, for example, when a measurement pad made mainly of metal is irradiated with an electron beam, the secondary electron energy generated changes depending on the potential given to the metal in advance. Then, an appropriate energy detection means is installed in the vacuum chamber, and the intensity of the detected secondary electron energy is converted into a change in the intensity of the secondary electron signal, which is then converted into a voltage, and then all measurements are performed. This is to check whether the brightness of the pad is modulated and displayed on the TV to understand and inspect the entire image as an image, or whether there is correspondence with the logic between the individual input and output bins. Specifically, a secondary electron energy analyzer consisting of a detector that measures the intensity of the secondary electron signal representing the energy of the secondary electrons emitted from the measurement pad is installed, and The S-curve relating to the signal intensity of the next electron emission is determined, and the voltage of the measurement pad is determined from this.

That is, as shown in FIG. 6, when the voltage applied to the mesh filter (analysis voltage) Vr is changed from negative to positive,
A known voltage (
sample voltage) vl (for example, -2■), the signal intensity T of the secondary electrons emitted from the measurement pad will change the S curve (analysis voltage vs. secondary electron signal intensity value curve) of Sl. Similarly, by applying a known voltage (sample voltage) 2 (for example OV) higher than vl to the same input/output bin, the S curve of S2 can be obtained in the same way.

At this time, the reference level Stl is set as a threshold value to an appropriate value between the maximum value and the minimum value of the secondary electron signal strength value T.

When set, the corresponding SLk value and each S curve Ss.

The difference between the intersection point Vt2 + Vrl with S2 (vrz v
r+) is found to be approximately equal to the sample voltage difference (V2 vl). Therefore, when testing a pad whose sample voltage is unknown among the measurement pads, try repeatedly measuring the feedback while changing the analysis voltage (■) appropriately and measuring the secondary electron signal strength T. By this, the analysis voltage V pH when the secondary electron signal intensity value T that coincides with the reference level S is finally obtained is determined, for example, Vr
The sample voltage of the measurement pad is determined from the tVrx value by V2-(vrz Vrx). Or,
Obtain S curves in advance for the entire expected sample voltage range between -, There are other ways to ask. All of these operations can be performed using hardware or software, but it takes time to find the analysis voltage that matches the reference voltage value Sub, so it takes a long time to obtain the measurement results. It required quite a bit of time.

[Problem to be solved by the invention]

The purpose of the present invention is to
The method of measuring the voltage of the measurement pad is still to detect the secondary electron signal intensity value while changing the analysis voltage, so the reference level S is dependent on the number of changes in the analysis voltage and the response speed of the analysis voltage. In view of the fact that it has been difficult to achieve high-speed, high-efficiency voltage measurement due to slow testing operations due to comparison operations, etc., we have developed an integrated circuit, In particular, it is an object of the present invention to provide an inspection apparatus that can increase the speed and efficiency of the inspection process for semiconductor integrated circuits such as ICs.

[Means to solve the problem]

The present invention has the following technical configuration to achieve the above object. That is, a vacuum part, a mounting part for the integrated circuit to be tested provided on the atmospheric part side surface of a partition forming a part of the vacuum part, and a plurality of integrated circuits to be tested placed on the mounting part. a plurality of measurement pads connected to each of the input/output bins by a signal line and exposed to the inner surface of the vacuum section of the partition; input/output wiring for the integrated circuit connected to at least a portion of the signal line; A beam irradiation means for irradiating the measurement pad with an electron beam and a means for detecting the intensity of a secondary electron signal generated from the measurement pad by the irradiation of the beam are provided in the vacuum part. , Furthermore, in conjunction with the vacuum section,
Beam deflection means for scanning an electron beam to selectively irradiate a predetermined measurement pad; voltage control means for applying a predetermined voltage to a filter means forming a part of the secondary electron signal intensity detection means; storage means for measuring and storing in advance the relationship between the secondary electron signal intensity value and the measurement pad voltage with respect to the voltage of the secondary electron signal intensity value detected from the measurement pad irradiated with the electron beam; and means for calculating the voltage of the measurement pad by referring to the relationship between the secondary electron signal intensity value and the pad voltage stored in the storage means.

That is, the integrated circuit testing device of the present invention, more specifically, the semiconductor integrated circuit testing device, has a filter means to which a predetermined voltage can be applied as a part thereof, in order to further improve the measurement accuracy of the previously proposed testing device described above. and means for controlling the voltage applied to the filter means, as well as means for controlling the voltage applied to the filter means. Unlike the conventional method of searching by repeating several inspection operations, the analysis voltage Vr is fixed in advance and maintained at a predetermined voltage, and the measuring pad is calculated from the detected secondary electron signal intensity value. It employs technology to determine voltage.

The secondary electron signal strength detecting means for performing secondary electron energy analysis used in the above-mentioned inspection apparatus used in the present invention detects the energy intensity of the secondary electrons emitted from the measurement pad by electron beam irradiation. Any device can be used as long as it can detect speed and convert the degree into an electrical signal (secondary electronic signal). Further, it is preferable that the secondary electron signal intensity detection means 30 is provided with a filter device 31 for controlling the passage of secondary electrons on the surface facing the measurement pad, and the filter device is a filter device 31 that controls the passage of secondary electrons. Among the secondary electrons, only those having a certain energy pass through a filter and reach the secondary electron signal strength detection means, for example, a mesh-like wire mesh to which a voltage can be applied. It is composed of
It is desirable that a voltage control circuit be added to this. When the secondary electron signal intensity value T is determined while changing the voltage of the filter, an S curve as shown in FIG. 6 described above can be drawn.

The inspection apparatus according to the present invention further includes a vacuum chamber 10 thereof.
A means 11 for generating an electron beam 23 is provided, for example, an electron gun, and a beam deflection means mainly composed of an electron lens 40 and a deflection coil 41 for narrowing the beam and deflecting the beam to a desired pad to be measured is provided. A means for controlling and driving these, such as a deflection coil driver means 42, is provided in conjunction with the vacuum section.

Next, regarding the voltage measurement of the measurement pad employed in the present invention, in the present invention, as described above, the analysis voltage of the filter means constituting a part of the secondary electron signal strength detection means is determined in advance. It is necessary to fix the voltage value, and for that purpose, a voltage control means such as an analysis voltage generator 3 is required.
2 is provided, and the relationship between the secondary electron signal value T for the predetermined voltage and the voltage of the measurement pad, that is, the sample voltage Vs is measured in advance by the Vs-T characteristic measuring section 44, and this is memorized. A storage means 43 stores a secondary electron signal strength value T stored in the storage means from a secondary electron signal strength value detected from the measurement pad to be inspected and a measurement pad voltage (sample voltage) Vs. and means for calculating the voltage of the measurement pad with reference to the relationship.

As a result of studying the relationship between the sample voltage (measurement pad voltage) Vs and the intensity T of the secondary electron signal, the inventors found that the intensity of the secondary electron signal detected by irradiating the measurement pad with an electron beam is It is known that it depends on the sample voltage Vs, and that a high signal strength T is detected when the voltage is low, but since only qualitative voltage levels can be known, the exact voltage value could not be determined. Fix the analysis voltage to a constant value,
Under these conditions, the pad voltage Vs and the secondary electron signal strength T are determined in advance.
(Vs-T characteristic) is determined for each pad, stored and registered, and the intensity of the secondary electron signal detected by irradiating the measurement pad with an electron beam during actual measurement is determined. It has been concluded that it is preferable to immediately obtain the pad voltage Vs by comparing the value T with the stored Vs-T characteristic.

The fixed analysis voltage used in the above is the voltage expected at the input/output pin of the IC under test in the S curve obtained from the filter applied voltage Vr of the secondary electron signal detection means and the secondary electron signal value T. 2 obtained when applying the maximum and minimum voltages to the measurement pad, respectively.
The applied voltage Vr at which the difference between the secondary electron signal intensity values T in the S curve of the species is the maximum is defined as the optimum analysis voltage value, and this is used. This optimum analysis voltage value is a voltage at which a Vs-T characteristic with the highest resolution can be obtained for the voltage range of the target measurement pad.

More specifically, for each measurement pad, the voltage Vs applied to the measurement pad is varied with the optimum analysis voltage value Vr fixed, and the secondary electron signal strength T value at that time is determined to determine the Vs - T characteristic. A curve or straight line is drawn and a certain function is derived from the graph and stored in a storage means 43 such as a parameter table. Therefore, when inspecting measurement pads in the present invention, by comparing and referencing the secondary electron signal intensity value T detected for each measurement pad and the corresponding function information in the storage means. It becomes possible to obtain the sample voltage value Vs, that is, the voltage of each measurement pad.

In the present invention, the X-Y coordinates of all measurement pads are recorded in a table provided in a part of the device, such as a microcomputer, and the A device that reads coordinate values from the table and transmits the data to beam deflection means composed of a deflection coil that controls electron beam irradiation means composed of an electron gun, thereby irradiating the beam onto a predetermined pad. It is. When the beam irradiation is performed, the secondary electron energy emitted from the measurement pad is measured by the secondary electron signal intensity detection means, and the measurement result is compared and referenced with the function value stored in the storage means, and the measurement pad is The voltage value vs is determined and the result is stored in a suitable memory provided in conjunction with the device, after which the voltage measurement of the fire measuring pad is repeated.

When such a repeated measurement operation is performed on a set of pins consisting of multiple input/output pins, the logic results registered in advance for that set of input/output pins are compared, and the logic results given in advance to each input/output pin are compared. If the measured output voltages and the measurement results all match, it is determined that the wiring of the - group of input/output bins is in accordance with the logic and is normal. Such measurements are performed on all input/output pins and necessary combinations of all input/output pins, and it is finally determined whether the IC to be tested is normal or not.

All such judgments are executed by software means using a microcomputer or the like.

A method for performing inspection using the semiconductor integrated circuit inspection apparatus according to the present invention is to drive the circuit according to a predetermined input/output signal wiring pattern and check the voltage values of all measurement pads by simultaneously displaying them as images. , a method of selecting a specific input/output pin and checking whether the voltage of each input/output pin is output correctly according to the preset and registered logic, or a method of checking whether the voltage of each input/output pin is output correctly according to the logic that is set and registered in advance, or the voltage is constant at the input bin of the specific input/output pin. A method of checking whether the output time delay at the output tip is within the normal range by applying a pulse of etc. are possible.

In addition, in the present invention, V for each measurement pad mentioned above
When determining the s-T characteristic relationship, remove the semiconductor integrated circuit such as the IC to be tested from the mounting section, and then connect the drive control section with the appropriate driver circuit and termination circuit to the input/output wiring pattern. The signal line is connected to all of the measurement pads via the signal line, and the functional relationship is determined for each measurement pad.

The reason for removing ICs and the like from the mounting part in such measurements is that when measuring the voltage of each input/output pin after driving the drive device, especially in the output bin, it is necessary to remove ICs and the like from the mounting section. This is because the output voltage changes depending on the logic used, so an accurate function cannot be determined.

Furthermore, when measuring the voltage Vs of the measurement pad in the present invention, the analysis voltage Vr, that is, the filter voltage is fixed and measured. The gain, offset m, etc. in the amplifier also need to be fixed.

[For production]

Since the present invention is an inspection device having the above-described configuration, by mounting an IC, etc., which is an object to be inspected, in a non-vacuum part, it is easy to cool the IC, etc., and it is possible to cool the IC etc. without destroying the vacuum part. It can be replaced with other ICs, etc.

Since the group of monitoring pads scanned by the electron beam are arranged in a concentrated manner, the above scanning is completed at once.

Further, since the secondary electron signal detection means having a voltage-controllable filter for detecting the secondary electron signal is used, the accuracy of the detected measurement pad voltage can be improved.

Further, in the voltage measuring means of the measurement pad in the present invention, the optimum analysis voltage value is determined in advance, the optimum analysis voltage value is fixed in advance, and the pad voltage value (Vs) is determined for each of the measurement pads. and secondary electron signal value (T)
A certain functional relationship is determined by determining the relationship between Since most of the measurement work can be performed automatically using software, the measurement work can be performed quickly and with high efficiency.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing a specific example of a semiconductor integrated circuit testing apparatus used in the present invention. That is, the inspection apparatus is provided with a mounting section 20 for mounting ICs, etc. 24 to be inspected on the atmospheric section side surface 13a of the substrate 13, which functions as a partition wall separating the vacuum section 14 and the atmospheric section 15. Insert and place the input/output pins. A measurement pad 21 made of a highly conductive metal such as copper is electrically connected to each input/output pin 25 of this IC, etc. via an arbitrary signal line 26 via the substrate 13, and is placed on the vacuum side of the substrate. surface exposed to 13
The voltage signal of the input/output pin 25 connected to the measurement pad 21 is measured by irradiating the measurement pad 21 with an electron beam 23 from a beam irradiator installed in the vacuum section. It is something to do.

The signal line 26 connecting the measurement pad 21 and each input/output pin of the semiconductor integrated circuit 24 has an input/output wiring pattern (16, 17) connected to an appropriate semiconductor integrated circuit driving device 34 in the substrate 13. It is connected. When measuring the voltage of the measurement pad, it is necessary to
Since it is necessary to measure the semiconductor integrated circuit to be tested such as C under the same conditions as when it operates under actual usage conditions, the control unit 3
Specifically, the input pin of a semiconductor integrated circuit such as an IC is connected to the driver circuit 36 of the drive device 34, and the output pin is connected to the termination circuit 37 of the drive device 34. .

The beam irradiation means 11 is usually an electron gun, and the electron beam 2 emitted from the beam irradiation means is
3 is appropriately focused by an electron lens 40, and then the direction of the beam is scanned by a deflection coil 41 to irradiate the beam onto a predetermined measurement pad. Such a deflection operation is performed by specifying the position of the measuring pad using X-Y coordinate values, etc., and storing it in a memory, for example, a parameter table 43 provided in a part of the pad voltage measuring means 49 via the input device 46, and When you want to irradiate a beam to a measurement pad, access the address of the measurement pad, read its X-Y coordinate value data, and control the deflection coil driver 42 to direct the beam 23 to the selected measurement pad. It is something that makes you

Next, in the present invention, as described above, the secondary electron signal detection means 30 that detects the secondary electron energy emitted from the measurement pad and converts the intensity value into an electric signal T is installed in the vacuum chamber 10. It is provided near the measurement pad 21 within the measurement pad 21 . Furthermore, the secondary electron signal strength detection means has as a part a filter means 31 to which a voltage can be applied to control the passage of secondary electrons. The filter means 3
Reference numeral 1 indicates that an optimum analysis voltage value, which will be described later, is applied by an analysis voltage generation circuit 32 that constitutes a part of a butt voltage measurement means 49 attached to the vacuum chamber, and an optimum analysis voltage value, which will be described later, is applied from the secondary electron signal intensity detection means. The detection signal is processed by the secondary electron signal detection circuit 33, which also constitutes a part of the pad voltage measuring means 49, and converted into a secondary electron signal intensity value T, which is then processed by a comparison reference circuit to be described later.

Next, the software compatible portion of the pad voltage measuring means in the present invention will be explained.

In the present invention, as described above, the voltage (2) to be applied to the filter, which is a part of the secondary electron signal strength detection means, that is, the analysis voltage, is fixed in advance to the optimum analysis voltage, and under that voltage, Vs -T It seeks characteristics.

Therefore, the principle of measuring the optimum analysis voltage will be explained with reference to FIG.

Both ends (-2
V, OV) is applied to the pad to be measured by the pad voltage setting section, and an electron beam is irradiated to create an S curve (IL S curve) for each voltage.
2))).

Next, the difference ΔT for 4JT in the secondary electron signal intensity for the S curve (1) and S curve (2) obtained = S curve (1) data (TI) - S curve (2) data (T2
) The analysis voltage with the largest value is the optimal analysis voltage.

Next, the principle for measuring the above-described Vs-T characteristics of each measurement pad in the present invention will be explained with reference to FIG. As described above, with the optimal analysis voltage for the pad to be measured set, the pad voltage setting section irradiates the electron beam while changing the voltage of the pad to be measured, and collects data on the pad voltage Vs vs. secondary electron signal strength T. obtain. A straight line approximating this relationship Secondary electron signal strength (T) = Ax pad voltage (Vs) + B
Convert it into a function, find its constants A and B, and register them as Vs-T characteristics. Note that the Vs-T characteristic is not necessarily limited to such linear approximation. Such Vs −T
When registering the measurement of characteristics, the IC to be inspected is removed from the mounting section, and a driver is connected to all measurement pads by a changeover switch of a driving device such as an IC, so that a specified voltage can be applied to a specified pad. After registering the parameters, insert the IC to be tested into the socket, and drive the IC by setting the changeover switch so that the driver is connected to the input pin of the IC and the termination circuit is connected to the output pin. The IC is inspected by measuring the voltage of the pin of interest. The voltage measurement unit 48 determines the pad voltage from the secondary electron signal T detected by irradiating the designated pad with an electron beam and the registered Vs-T characteristic. This calculation process is executed by the Vs-T characteristic measuring section 44 that constitutes a part of the pad voltage measuring means 49.

In the present invention, ' is the deflection position determined for each measurement pad as described above, the optimum analysis voltage, Vs-
The T characteristic is registered in a parameter table 43 forming a part of the pad voltage measuring means 49. It is preferable that the registration is performed in the order of the optimum analysis voltage and the Vs-T characteristic.

Next, the operating procedure of the semiconductor integrated circuit testing apparatus according to the present invention will be explained according to the flowchart shown in FIG.

When the number i of the measurement pad to be tested is input (step a), the optimum analysis voltage value corresponding to the measurement pad number i is read out from the parameter table and applied to the filter means of the secondary electron signal intensity detection means. Setting (Step b) Next, the deflection coordinate value corresponding to the measurement pad numbered i is read out from the parameter table and set in the electron beam deflection coil driver.

(Step C) After that, the beam is irradiated onto the measurement pad numbered i (
Step d) Secondary electrons are detected by the secondary electron signal strength detection means, and the signal strength T thereof is determined by the secondary electron detection circuit (Step e
) When the beam is interrupted (step f), compare and refer to the secondary electron signal intensity value T obtained in step e and the Vs-T characteristic function of the measurement pad with number i recorded in the parameter table. Pad voltage Vs = (T-B)/
A pad voltage Vs corresponding to the T value is calculated using the formula A (step g). Next, the calculated pad voltage Vs is recorded and saved and displayed as necessary (step h).
) The same measurement operation is repeated for all the input/output pins of the necessary ICs, etc., and finally it is determined whether the semiconductor integrated circuit under test is operating according to the designed logic, and defective products are rejected. excluded from.

〔Effect of the invention〕

According to the present invention, since the IC, etc. to be inspected is mounted in a non-vacuum area rather than a vacuum area, it is easy to cool the IC, etc., and even if the IC etc. easily generates heat, it can be easily cooled down during the inspection. It is possible to prevent heat generation from ICs, etc., and to obtain accurate test results without the influence of heat.

Furthermore, since ICs and the like are mounted in the non-vacuum section, the vacuum state can be maintained in the vacuum section even after the inspection of the negative IC, etc. is completed, and by removing it and mounting the next IC, etc. Therefore, there is no need to operate the vacuum pump to form a vacuum section each time an IC or the like is mounted. However, after removing the - IC etc. and installing another IC etc.,
Inspection of this IC etc. can be started immediately.

In other words, it is possible to test a plurality of ICs and the like continuously and sequentially.

In addition, since the measurement pads are concentrated in one place, the electron beam can scan all the monitor pads at once without changing the position of the electron gun, etc. The time required for inspection can be shortened.

Furthermore, in the present invention, it is possible to accurately capture and analyze the secondary electron energy emitted from the measurement pad by beam irradiation, so it is not only possible to accurately measure the pad voltage, but also to Since the analysis voltage when measuring the electron signal intensity is fixed and the pad voltage can be immediately obtained by referring to the Vs-T characteristic function determined in advance from the detected secondary electron signal intensity,
As long as the Vs-T characteristic function is determined in advance, semiconductor integrated circuits such as ICs can be tested extremely quickly and efficiently using software means, which can improve industrial testing efficiency. A reduction in the cost required for inspection can be expected.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing a semiconductor integrated circuit testing apparatus according to the present invention. FIG. 2 shows a principle diagram for determining the optimum analysis voltage in the present invention. FIG. 3 is a diagram showing an example of the Vs-T characteristic function in the present invention. FIG. 4 is a flowchart for operating the inspection device of the present invention. FIG. 5 is a basic configuration diagram of a semiconductor integrated circuit testing apparatus according to the present invention. FIG. 6 is a diagram showing the principle of a conventional method for measuring sample voltage. 10... Vacuum chamber, 11... Electron beam irradiation means, 12... Vacuum pump, 13... Substrate, 14...
・Vacuum part, 15... Atmospheric part, 16... Wiring pattern for signal input, 17... Wiring pattern for signal output, 20... Semiconductor integrated circuit mounting part, 13a... Atmospheric part of substrate Side surface, 13b... Vacuum part side surface of substrate, 21... Measurement pad, 23... Beam, 24, 2
4', 24"...Semiconductor integrated circuit to be tested, 25
...Input/output bin, 26...Signal line, 30...Secondary electron signal strength detection means, 31...Filter means, 32...Analysis voltage generation circuit, 33...Secondary electron detection Circuit, 34... Drive device for semiconductor integrated circuit, 35... Control unit, 36... Driver circuit, 37... Terminating circuit, 40... Electronic lens, 41... Deflection coil, 42... ...Deflection coil driver 43...Parameter table, 44...Vs-T characteristic measuring section, 45...Measurement result output device, 46...Input device, 47...Optimum analysis voltage measuring section, 48... Pad voltage measuring section, 49... Pad voltage measuring means.

Claims (1)

[Claims] 1. A vacuum section, a mounting section for an integrated circuit to be tested provided on the atmospheric section side surface of a partition wall forming a part of the vacuum section, and a mounting section for an integrated circuit to be tested placed on the mounting section. a plurality of measurement pads connected to each of the plurality of input/output pins of the integrated circuit for use by a signal line and exposed to the inner surface of the vacuum part of the partition wall; connected to at least a portion of the signal line; An input/output wiring pattern for the integrated circuit, and a beam irradiation means for irradiating the measurement pad with an electron beam in the vacuum section, and a secondary electron signal intensity generated from the measurement pad by irradiation of the beam. A detection means is provided, and is further provided in conjunction with the vacuum section,
A beam deflection means for scanning an electron beam to selectively irradiate a predetermined measurement pad; a voltage control means for applying a predetermined voltage to a filter means forming a part of the secondary electron signal detection means; a storage means for measuring and storing in advance the relationship between the secondary electron signal intensity and the measurement pad voltage with respect to the voltage; 1. An integrated circuit testing device comprising: means for calculating a voltage of a measurement pad by referring to a relationship between a secondary electron signal intensity value stored in a storage means and a pad voltage. 2. The inspection device according to claim 1, wherein the voltage applied to the filter means constituting a part of the secondary electron signal strength detection means is fixed. 3. The fixed voltage is predicted at the input/output pin of the semiconductor integrated circuit under test in the S curve obtained from the applied voltage Vr of the secondary electron signal strength detection means and the secondary electron signal strength value S. The applied voltage V at which the difference between the secondary electron signal intensity values is maximum in the two types of S curves obtained when the maximum and minimum voltages are respectively applied to the measurement pad.
The inspection device according to claim 1 or 2, characterized in that the optimum analysis voltage value is expressed by r. 4. Claim 1, wherein the storage means stores the relationship between the voltage value Vs of the measurement pad and the secondary electron signal strength value S at the optimum analysis voltage value in the form of a predetermined function. 3. The inspection device according to 3.