JP2007071710A - Probing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique capable of improving measurement efficiency of electrical properties of micro-elements by avoiding breakage of probes due to false selection of probes in a probing devices. <P>SOLUTION: When a probe selected is moved while looking at SEM imagery projected on an operating screen, the varied values are monitored of SEM imagery projected on the operating screen, if the varied values of SEM imagery is larger than a noise level, judgment that right probe is selected is obtained resulting in continuous migration of the selected probe, while if the varied values of SEM imagery is equal or less than a noise level, judgment that wrong probe is selected is obtained resulting in making an end to migration of the selected probe. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a probing apparatus, and in particular, a technique effective when applied to a probing apparatus that evaluates the electrical characteristics of a microelement by directly contacting a plurality of probes with, for example, a nanometer-scale microelement wiring or contact. It is about.

  A sample in which a fine metal wire and further a submicron-scale metal wiring and a micron-scale metal electrode are formed on a nanometer-scale element is moved to the ultra-high vacuum prober chamber and electrically connected to the metal electrode using the ultra-high vacuum prober And an evaluation method for measuring the electrical characteristics of the nanometer scale element is disclosed (for example, see Patent Document 1).

  The probe cantilever and probe are made conductive, and the probe is provided with a voltage value acquisition circuit. First, the probe is used as a probe for an atomic force microscope to determine the voltage measurement location on the fine wiring. Next, a voltage measuring device is disclosed in which a probe is brought into contact with a fine wiring and a voltage is measured through a voltage value acquisition circuit unit (see, for example, Patent Document 2).

A plurality of probes having sharp tips are tilted (30 to 60 °) from the normal of the sample surface and arranged at intervals of an azimuth angle of 30 ° or more, so that a plurality of probes are simultaneously provided in the submicron region. An electronic element evaluation apparatus is disclosed that performs characteristic analysis of circuit elements on an actual device by bringing them into contact with each other (see, for example, Patent Document 3).
JP 2002-289621 A (paragraphs [0037] to [0040], FIG. 6) JP-A-5-251523 (paragraphs [0022] to [0030]) JP-A-9-26436 (paragraph [0022], FIG. 15)

  For example, there is a probing apparatus that measures the electrical characteristics of a microelement by directly contacting a plurality of probes with the wiring or contact of a nanometer scale microelement. This probing device uses a probe with a tip diameter of about 10 to 500 nm. While observing the SEM (Scanning Electron Microscope) image displayed on the operation screen, the movement of multiple probes can be observed. It operates with 3 axes of XYZ. The SEM scans the surface of a sample with a micro electron probe, receives secondary electrons or reflected electrons emitted from the surface with a detector, and displays the intensity as an image of a bright spot array on a monitor synchronized with probe scanning. It is an electron microscope and can observe the fine structure or form of the surface of a sample. Each probe can be selected by an operation screen or a switch of a dedicated controller of the probing apparatus, and which probe is selected can be confirmed by an SEM image displayed on the operation screen. Furthermore, the position of the selected probe can be displayed with a color marker on the operation screen.

  However, the probe selected by the operator (the probe that the operator wants to move), such as when the operator is enthusiastic about characterization of microelements or after an unintentional interruption, actually Unlike the selected probe (the probe that the operator does not want to move), an erroneous operation of the probe may occur that moves the probe that the operator does not want to move instead of the probe that the operator does not want to move. Such erroneous operation of the probe easily causes damage to the probe by causing the probes or the probes to collide with the sample surface. Since the tip of the probe is fine, if the probe breaks, the electrical characteristics of the microelement cannot be measured, and the probe must be replaced. However, since the probe replacement operation takes about 20 minutes per probe, this causes a problem that the measurement time of the electrical characteristics of the microelements becomes long and the measurement efficiency decreases.

  An object of the present invention is to provide a technique capable of improving the measurement efficiency of electrical characteristics of microelements in a probing apparatus by avoiding damage to the probe due to erroneous selection of the probe.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  The present invention is a probing for measuring the electrical characteristics of a microelement by operating a plurality of probes while directly viewing the SEM image displayed on the operation screen and bringing the plurality of probes into direct contact with the electrodes of the microelements. When the selected probe is moved, the apparatus monitors the change value of the SEM image displayed on the operation screen. If the change value of the SEM image is larger than the noise level, the correct probe is selected. The movement of the selected probe is continued, and if the change value of the SEM image is equal to or smaller than the noise level, it is determined that the wrong probe is selected and the selected probe is selected. The movement of is stopped.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  Since the probe can be prevented from being damaged due to the movement of the wrongly selected probe, the number of probe replacements can be reduced, the time required to measure the electrical characteristics of the microelements can be shortened, and the measurement efficiency can be improved. it can.

  In this embodiment, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments. However, unless otherwise specified, they are not irrelevant to each other. Some or all of the modifications, details, supplementary explanations, and the like are related.

  Also, in this embodiment, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), unless otherwise specified, or in principle limited to a specific number in principle. The number is not limited to the specific number, and may be a specific number or more. Further, in the present embodiment, the constituent elements (including element steps and the like) are not necessarily essential unless particularly specified and apparently essential in principle. Yes. Similarly, in this embodiment, when referring to the shape, positional relationship, etc. of the component, etc., the shape, etc. substantially, unless otherwise specified, or otherwise considered in principle. It shall include those that are approximate or similar to. The same applies to the above numerical values and ranges.

  In the drawings used in the present embodiment, hatching may be added even in a plan view for easy understanding of the drawings. In the present embodiment, a MIS • FET (Metal Insulator Semiconductor Field Effect Transistor) representing a field effect transistor is abbreviated as MIS.

  In all the drawings for explaining the embodiments, components having the same function are denoted by the same reference numerals in principle, and the repeated description thereof is omitted. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
A method for preventing erroneous selection of the probe provided in the probing apparatus according to the first embodiment will be described with reference to FIGS. Here, among the probing apparatuses, a probing apparatus that measures the electrical characteristics of a nanometer-scale microelement, for example, a MIS having a gate length of about 0.1 to 0.8 μm is illustrated.

  First, the probing apparatus according to the first embodiment will be described with reference to FIGS. FIG. 1 is an overall schematic diagram of a probing device, and FIG. 2 is a configuration diagram of a probe operation unit of the probing device.

  As shown in FIG. 1, the probing apparatus 1 is roughly composed of a sample chamber 2, a vacuum system 3, a probe replacement mechanism 4, an electron beam mechanism 5, a probe operation unit 6, and a measurement unit 7. Further, the sample chamber 2 includes a first sample chamber for exchanging the probe and a second sample chamber for measuring the electrical characteristics of the microelements. For example, the vacuum system 3 includes a turbo pump 3a and a dry pump 3b. Thus, the first and second sample chambers can be maintained in a vacuum state. In the sample chamber 2, a sample moving mechanism 9 for placing a sample 8 on which microelements are formed and a probe moving mechanism 11 that can be equipped with a plurality of (for example, six) probes 10 are installed. The stage 12 on which the sample moving mechanism 9 and the probe moving mechanism 11 are mounted can move in the first and second sample chambers. A partition may be provided between the first sample chamber and the second sample chamber.

  In the first sample chamber, the damaged probe 10 is replaced. A plurality of unused probes 10 are stored in advance in the probe stock 13, and after the probe moving mechanism 11 is moved to the first sample chamber, the damaged probe 10 is damaged using the probe replacement mechanism 4. And replace the unused probe 10. In the second sample chamber, each probe 10 newly attached to the probe moving mechanism 11 is brought into direct contact with each pattern constituting the microelement formed on the sample 8. The image of the microelement formed on the sample 8 and the image of each probe 10 in the second sample chamber are transferred to the operation screen 14 of the probe operation unit 6 as an SEM image obtained by the electron beam mechanism 5. The operator can directly contact each probe 10 with each pattern constituting the microelement formed on the sample 8 by operating each probe 10 while viewing the SEM image. The electrical characteristics of the microelements formed on the sample 8 are measured by the measurement unit 7.

  Further, as shown in FIG. 2, the probe operation unit 6 includes an operation screen 14 on which an SEM image is displayed, an SEM control unit 6 a that controls the operation screen 14, and a stage control unit 6 b that controls the movement of the stage 12. The probe control unit 6c controls the movement of each probe 10 with three axes XYZ. The probe control unit 6c further includes a probe selection unit 6c1 for selecting each probe 10 and each probe. And an XYZ-axis adjusting unit 6c2 for adjusting 10 XYZ triaxial coarse and fine movements.

  Next, an operation method in which the tip of the probe is brought into direct contact with each pattern constituting the microelement according to the first embodiment will be described with reference to FIGS. FIG. 3 is a schematic diagram of an SEM image displayed on the operation screen when the probe is operated, and FIG. 4 is an enlarged schematic diagram of a part of the SEM image displayed on the operation screen.

  As shown in FIG. 3, the tip diameter of the probe 10 is considered to be an appropriate range of, for example, 10 to 500 nm (not to be limited to this range depending on other conditions). Further, as a range suitable for mass production, a peripheral range having a central value of 100 nm such as 50 to 200 nm is considered most preferable. The tip of the probe 10 is brought into direct contact with each pattern constituting the microelement, for example, each ellipse or substantially circular electrode 15 having a diameter of about 100 to 500 nm, and the electrical characteristics of the microelement are measured. The tip of the probe 10 can be directly brought into contact with, for example, a plug connected to the gate electrode and the source / drain of the MIS, and the electrical characteristics of the MIS can be measured. Further, the tip end of the probe 10 can be directly brought into contact with, for example, the wiring, and the wiring resistance or the contact resistance can be measured. When the tip of the probe 10 is brought into direct contact with each pattern constituting the microelement, the stylus 10 is observed while observing the SEM image displayed on the operation screen 14 using an XYZ triaxial drive mechanism. Bring the tip close to the desired location.

  At this time, as shown in FIG. 4, the probe 10a to be operated is enlarged on the operation screen 14 so that the position of the tip of the probe 10 can be easily observed, and an SEM image is observed.

  By the way, if the operation target probe 10a is moved, a change always occurs in the SEM image displayed on the operation screen 14 in which the tip of the operation target probe 10a is in the field of view. If there is no change other than noise in the SEM image displayed on the operation screen 14 even though the operator intends to operate the probe 10a to be operated, the probe 10a to be operated is selected. It is thought that it is not.

  Therefore, in the first embodiment, in order to recognize the correctness of the selection of the probe, the change of the SEM image displayed on the operation screen 14 when the probe 10 is operated is monitored, and the change value of the SEM image is monitored. If the noise level is larger than the noise level, it is determined that the correct probe (manipulation target probe 10a) is selected, and the selected probe 10 (manipulation target probe 10a) continues to move to change the SEM image. If the value is equal to or smaller than the noise level, it is determined that the wrong probe is selected, and the movement of the selected probe 10 is stopped.

  Next, a method for preventing an erroneous operation of the probe by monitoring changes in the SEM image displayed on the operation screen will be described in detail with reference to FIGS. 5, 6, and 7. FIG. 5 is a schematic diagram of an SEM image displayed on the operation screen when operating a correctly selected probe. FIG. 6 is an image displayed on the operation screen when operating an erroneously selected probe. FIG. 7 is a schematic diagram showing a sequence for preventing an erroneously selected probe operation.

  As shown in FIG. 5, when the correctly selected probe (operation target probe 10a) is being operated, the operator is observing the operation target probe 10a, and is thus displayed on the operation screen 14. In the SEM image, it is observed that the probe 10a to be operated is moving. Although the change value of the SEM image is recorded simultaneously with the movement of the probe 10, if the probe 10a to be operated is moved, the change value of the SEM image becomes a noise level as shown in the area A of FIG. Bigger than. Therefore, if the change value of the SEM image is larger than the noise level, it is determined that the probe 10a to be operated is selected, a warning from the probing device 1 is not issued, and the movement of the probe 10a to be operated is not performed. Continued.

  On the other hand, as shown in FIG. 6, when an erroneously selected probe (probe 10b other than the operation target) is operated, the operator observes the operation target probe 10a. Therefore, the movement of the probe 10a to be operated is not observed in the SEM image displayed on the operation screen 14. Although the change value of the SEM image is recorded simultaneously with the movement of the probe 10, as shown in the area B of FIG. 7, the change value of the SEM image is equal to or smaller than the noise level. At this time, it is immediately determined that the probe 10b other than the operation target is selected, and the movement of the probe 10b other than the operation target is stopped. A warning is issued to the operator by voice or message before, after, or simultaneously with the stop of the movement of the probe 10b other than the operation target.

  If the operation of the probe 10b other than the operation target is mistakenly continued, the probe 10b other than the operation target continues to move until the selection error is noticed, so that not only the microelements are damaged but also the probes 10 collide with each other. The needle 10 is damaged. Since the tip of the probe 10 is fine, if the probe 10 is damaged, the electrical characteristics of the microelements cannot be measured and the probe 10 must be replaced. Since the replacement work takes about 20 minutes per one, the measurement time of the electrical characteristics of the microelements becomes long, resulting in a problem that the measurement efficiency is lowered.

  However, according to the first embodiment, when the change value of the SEM image is equal to or smaller than the noise level, it is determined that the probe 10b other than the operation target is selected and selected. The operation of the existing probe 10 is stopped. Thereby, the damage of the probe 10 due to the movement of the probe 10 selected by mistake can be avoided, and the number of times of replacement of the probe 10 is reduced. Therefore, the electrical characteristics of the microelement including the replacement operation of the probe 10 can be reduced. The time required for the measurement can be shortened, and the measurement efficiency of the electrical characteristics of the microelement can be improved.

(Embodiment 2)
In the second embodiment, whether or not the probe is selected is determined from the probe current flowing through the probe. A method for preventing erroneous selection of the probe of the probing apparatus according to the second embodiment will be described with reference to FIG. FIG. 8 is a schematic diagram for explaining the probe detection method using the probe current according to the second embodiment.

  When the tip of the probe 10 is brought into direct contact with each pattern constituting the microelement, for example, a plug connected to the gate electrode or source / drain of the MIS, the position of the tip of the probe 10 can be easily observed. Further, the probe 10 is enlarged on the operation screen 14 of the probing apparatus 1 to observe the SEM image. When the correctly selected probe (manipulation target probe 10a) is operated, it is observed that the operation target probe 10a is moving in the SEM image displayed on the operation screen 14. At this time, the probe 10a to be operated is irradiated with electrons irradiated from the electron gun of the SEM, so that a probe current flows through the ammeter 16 connected to the probe 10a to be operated. On the other hand, no probe current flows through the ammeter 16 connected to the probe 10 that is not displayed on the operation screen 14.

  Accordingly, an ammeter is connected to all the probes 10 to constantly monitor the probe currents flowing through all the probes 10, and an interlock mechanism is provided that disables the movement of the probes 10 where no probe current flows. Thus, if a probe current is flowing through the ammeter 16 connected to the selected probe 10, it is determined that the correct probe (manipulation target probe 10a) is selected, and the operation target probe is selected. The movement of 10a is continued, but if no probe current is flowing through the ammeter 16 connected to the selected probe 10, it is determined that the wrong probe is selected, and the probe 10 is interlocked. Can be prevented from moving.

  As described above, according to the second embodiment, when no probe current flows through the ammeter 16 connected to the selected probe 10, it is determined that the probe 10 is selected incorrectly, and the interlock mechanism This makes it impossible to move the probe 10 selected by mistake. Thereby, the breakage of the probe 10 due to the movement of the erroneously selected probe 10 can be avoided, and the same effect as in the first embodiment described above can be obtained.

(Embodiment 3)
In the third embodiment, whether the probe is selected correctly or not is determined from the probe mounting angle. A method for preventing erroneous selection of the probe of the probing apparatus according to the third embodiment will be described with reference to FIG. FIG. 9 is a schematic diagram of the SEM image displayed on the operation screen for explaining the SEM image overlay display method of the probe to be operated according to the third embodiment.

  Since the angle at which each probe 10 is mounted is determined in advance, it is possible to define in which direction each probe 10 is observed in the SEM image displayed on the operation screen. Therefore, an image of the probe 10a to be operated is assumed in advance, for example, as indicated by an arrow 17 in FIG. 9, and the arrow 17 and the SEM image are displayed in an overlapping manner, thereby erroneously selecting the probe 10. Can be prevented.

  When the correctly selected probe (manipulation target probe 10a) is being operated, the probe 10 moves in the same direction as the direction (angle) of the arrow 17, but the erroneously selected probe is operated. In this case, since the arrow 17 does not overlap the SEM image of the probe 10a to be operated, the operator can recognize that he is operating the probe 10b other than the operation target. Furthermore, the recognition of the selected probe 10 can be made clearer by linking to the magnification and displaying the tip of the probe 10 on the operation screen.

  As described above, according to the third embodiment, the operator operates by displaying the image of the probe 10a to be operated (for example, the arrow 17) so as to overlap the SEM image displayed on the operation screen. Therefore, it is possible to prevent the erroneously selected probe 10 from moving. Thereby, the breakage of the probe 10 due to the movement of the erroneously selected probe 10 can be avoided, and the same effect as in the first embodiment described above can be obtained.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  For example, in the above-described embodiment, the probing apparatus that measures the electrical characteristics of nanometer-scale microelements has been described. However, the present invention can be applied to other multi-probing systems using a probe having a fine tip diameter, for example. In addition, the destruction of the probe due to an erroneous operation of the probe can be avoided, and the measurement efficiency of the electrical characteristics of the microelement can be improved.

  The present invention can be applied to a probing apparatus or a multi-probing system using a fine probe having a tip diameter of 10 to 500 nm (typically about 100 nm).

1 is an overall schematic diagram of a probing device according to a first embodiment of the present invention. It is a block diagram of the probe operation part of the probing apparatus by Embodiment 1 of this invention. It is a schematic diagram of the SEM image displayed on the operation screen when operating the probe according to the first embodiment of the present invention. It is the schematic diagram which expanded a part of SEM image projected on the operation screen. It is a schematic diagram of the SEM image displayed on the operation screen when operating the correctly selected probe according to the first embodiment of the present invention. It is a schematic diagram of the SEM image displayed on the operation screen when operating the erroneously selected probe according to the first embodiment of the present invention. It is a schematic diagram which shows the sequence which prevents operation of the probe selected accidentally by Embodiment 1 of this invention. It is a schematic diagram explaining the detection method of the probe using the probe current by Embodiment 2 of this invention. It is a schematic diagram of the SEM image displayed on the operation screen explaining the SEM image overlay display method of the probe to be operated according to the third embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Probing apparatus 2 Sample chamber 3 Vacuum system 3a Turbo pump 3b Dry pump 4 Probe exchange mechanism 5 Electron beam mechanism 6 Probe operation part 6a SEM control part 6b Stage control part 6c Probe control part 6c1 Probe selection part 6c2 XYZ axis Adjustment unit 7 Measuring unit 8 Sample 9 Sample moving mechanism 10 Probe 10a Probe 10b to be operated Probe 11 other than operation target Probe moving mechanism 12 Stage 13 Probe stock 14 Operation screen 15 Electrode 16 Ammeter 17 Arrow

Claims (5)

While observing the SEM image displayed on the operation screen, the plurality of probes are operated, and the plurality of probes are brought into direct contact with each pattern constituting the microelements to measure the electrical characteristics of the microelements. A probing device,
When moving the selected probe, the change value of the SEM image displayed on the operation screen is monitored, and if the change value of the SEM image is larger than the noise level, it is determined that the correct probe is selected. The movement of the selected probe is continued, and if the change value of the SEM image is equal to or smaller than the noise level, it is determined that the wrong probe is selected, and the selected probe is moved. Probing device characterized in that movement is stopped.   2. The probing apparatus according to claim 1, wherein a tip diameter of the probe is 10 to 500 nm.   2. The probing apparatus according to claim 1, wherein a warning is issued by voice or a message before, after, or simultaneously with the movement of the selected probe. While observing the SEM image displayed on the operation screen, the plurality of probes are operated, and the plurality of probes are brought into direct contact with each pattern constituting the microelements to measure the electrical characteristics of the microelements. A probing device,
An ammeter is connected to each of the plurality of probes to monitor the probe current flowing through the plurality of probes. If the probe current is flowing through the ammeter connected to the selected probe, a correct probe is obtained. If the probe current does not flow through the ammeter connected to the selected probe, it is determined that the wrong probe is selected. Then, the probing apparatus is characterized in that the movement of the selected probe is stopped. While observing the SEM image displayed on the operation screen, the plurality of probes are operated, and the plurality of probes are brought into direct contact with each pattern constituting the microelements to measure the electrical characteristics of the microelements. A probing device,
An image of the probe to be operated is assumed in advance, the image of the probe to be operated and the SEM image displayed on the operation screen are displayed in an overlapping manner, and the selected probe has the same direction as the image. If it moves to, it is determined that the correct probe is selected, and the movement of the selected probe is continued. If the image does not overlap the SEM image of the selected probe, the wrong probe is selected. The probing apparatus is characterized in that the movement of the selected probe is stopped when it is determined that the probe has been detected.

Images