JP2004279431A - Manipulator and probe device, sample fabricating device and sample observing device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manipulator for improving the operating rate of a device by shortening a time for stopping the device during replacing a probe. <P>SOLUTION: An air lock room is provided in a vacuum chamber and the air lock room is connected to the vacuum chamber of a body with a vacuum bellows. A probe holder is mounted in the air lock room so that the probe is moved together with the air lock room by a moving mechanism provided on the body. The air lock chamber is evacuated through an exhaust port and the air lock room is partitioned from the vacuum chamber with a vacuum valve. The probe has a second moving mechanism so that it can be moved between the air lock room and the vacuum chamber. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a manipulator for a micro-tip in a vacuum, and particularly to a probe device for evaluating the performance of an electronic element or analyzing a failure, or a portion necessary for analysis and observation from a sample piece using a focused ion beam. The present invention relates to a sample preparation apparatus for processing and extracting only a sample.

  There is a prober as a conventional method for evaluating an electronic device. This is a method in which a probe is brought into contact with a position where electrical characteristics are to be measured while observing an inspection sample with an optical microscope in the atmosphere. By providing the probe with a voltage applying unit and a current measuring unit, it is possible to evaluate the current-voltage characteristics of the element and to specify a conduction failure portion.

  In recent years, semiconductors have been highly integrated, and techniques for evaluating electronic devices having submicron wiring have been devised. For example, as disclosed in Patent Document 1, in the above-described prober, instead of an optical microscope, a sample is irradiated with charged particles in a vacuum, and microscopic means for detecting secondary electrons thereof (such as an electron microscope) The probe is brought into contact with the sample by a high-precision probe moving mechanism.

  In addition, due to the high integration of semiconductors, the necessity of analysis of extremely fine objects that cannot be measured with the resolution of a scanning electron microscope (hereinafter abbreviated as SEM) is increasing. For this reason, a transmission electron microscope (hereinafter abbreviated as TEM) having a high observation resolution has been regarded as a promising alternative to the SEM. In order to observe with a TEM, it is necessary to make the thickness of the observation portion of the sample as thin as 0.1 μm. As an example of this processing procedure, first, a strip-shaped pellet including a region to be observed is cut out from a sample such as a wafer using a dicing apparatus. A part of the pellet is irradiated with a focused ion beam (hereinafter abbreviated as FIB) to form a thin-walled part. At the time of TEM observation, the thin wall surface is irradiated with an electron beam vertically.

  Disadvantages of this method are that the work involved in preparing one sample is complicated, and that there is a part that cannot be analyzed because the wafer is cut.

  On the other hand, Patent Document 2 discloses the following method. This is a method of cutting out a sample only by FIB processing while changing the posture of the sample. Here, as a sample extracting means after cutting out, an operating needle having the same shape as the probe of the prober described above is brought into contact with the sample, a deposition gas is supplied, and an ion beam assisted deposition film is formed. And the sample are bonded, and separated from the wafer.

JP-A-9-326425

JP-A-5-52721

  However, a problem common to the former probe device and the latter sample preparation device is that a probe or an operating needle (hereinafter, referred to as a probe) is brought into contact with a sample, thereby causing deterioration of a probe tip. A method of detecting contact to make the load and displacement such that the deformation of the probe when it is brought into contact with the sample falls within the elastic deformation region is also being studied. However, since the state of the contact surface is not always the same, for example, the surface of the sample is covered with an insulator, the probe may be pressed against the sample more than necessary due to poor contact detection of the probe. As a result, the tip of the probe is plastically deformed, and it becomes difficult to use the probe after the next time. This problem becomes more remarkable as the degree of integration of the semiconductor increases and the tip of the probe becomes thinner.

  Speaking of the latter sample preparation apparatus alone, the probe tip must be cut off when the probe tip is bonded to the sample and the sample is separated from the wafer, and then another sample is prepared and extracted. This cutting can be performed by the FIB, and the cut surface can be sharpened by the FIB. However, since only a planar processing is performed, the probe becomes a wedge-shaped probe that is thick in the thickness direction. Therefore, there is a limit for repeated use.

  For all of the above reasons, the probe is a consumable item in any device and needs to be replaced quite frequently. By the way, the manipulator for moving the probe attached to these devices has a mechanical unit and a probe integrated with each other, and it is necessary to open the vacuum chamber to the atmosphere and remove it from the main body when replacing the probe. Therefore, it takes a long time to start up the vacuum after the replacement, which causes a reduction in the operation rate of the apparatus.

  In order to solve the above problems, the present invention uses the following means.

  There is provided a vacuum introduction mechanism that can be used when the probe is taken in and out of the vacuum chamber that is the apparatus main body without opening the vacuum chamber to the atmosphere. Specifically, an airlock chamber is provided in the vacuum chamber, and the airlock chamber is connected to a vacuum chamber of the main body by a flexible vacuum bellows. The member holding the probe is attached to the airlock chamber, and the probe can be moved together with the airlock chamber by a moving mechanism provided in the main body. The airlock chamber has a structure capable of evacuating, and the airlock chamber and the vacuum chamber are separated by a vacuum valve. A second moving mechanism is provided so that the probe can move between the airlock chamber and the vacuum chamber.

  According to the present invention, it is not necessary to open the vacuum chamber to the atmosphere when the probe is moved in and out of the vacuum chamber of the main body, so that the operation rate of the apparatus can be improved.

  FIG. 1 is a schematic configuration diagram of a manipulator showing one embodiment of the present invention. In the figure, an airlock chamber 3 connected by a vacuum bellows 2 is provided in a vacuum chamber 1 which is a main body of the apparatus. The probe holder 5 on which the probe 4 is mounted is fixed to the airlock chamber 3 via a vacuum seal 6, and the three-axis moving mechanisms 7 a, 7 b, 7 c provided in the vacuum chamber 1 provide a probe together with the airlock chamber 3. 4 movements are possible. The partition between the air lock chamber 3 and the vacuum chamber 1 is constituted by a vacuum valve 8 that can be opened and closed, and the air lock chamber 3 can be evacuated / opened to the atmosphere from an exhaust port 9. The probe holder 5 is provided with a uniaxial moving mechanism 10 so that the probe 4 can move between the airlock chamber 3 and the vacuum chamber 1.

  Here, the operation of the present embodiment will be described. When exchanging the probe 4, as shown in FIG. 2A, the probe holder 5 is retracted using the moving mechanism 10, and the vacuum valve 8 is closed. Thereby, the air lock chamber 3 becomes a separate space from the main body vacuum chamber 1. Here, air is introduced into the air lock chamber 3 from the exhaust port 9 to make the inside of the air lock chamber 3 atmospheric pressure. Thereafter, the probe holder 5 is removed from the airlock chamber 3, and the probe 4 is replaced after the state shown in FIG. After the replacement, the probe holder 5 is attached to the airlock chamber 3 in the reverse order, and the airlock chamber 3 is evacuated. After confirming that the pressure difference between the air lock chamber 3 and the vacuum chamber 1 has disappeared, the vacuum valve 8 is opened. The probe holder 3 is introduced into the vacuum chamber 1 by the moving mechanism 10. To operate the probe 4 at a desired position, the airlock chamber 3 is moved together with the three-axis moving mechanisms 7a, 7b, 7c. Thus, the probe can be replaced without exposing the vacuum chamber to the atmosphere.

  FIG. 3 is a detailed sectional view of a manipulator showing another embodiment of the present invention. FIG. 4 is a plan view of FIG. 3, and FIG. 5 is a sectional view taken along the line AA of FIG.

  In the figure, a base flange 32 is fixed to a vacuum chamber 31 which is an apparatus main body by using a vacuum seal 33. The air lock chamber 34 is connected to the base flange 32 via a vacuum bellows 35, and a vacuum valve 37 is provided on an end face of the air lock chamber 34. The opening and closing of the vacuum valve 37 is performed by rotating a cylindrical valve opening and closing mechanism 38 formed in the air lock chamber 34. In the air lock chamber 34, an exhaust pipe 39 is attached to the base flange 32 via a vacuum bellows 40 and communicates with an exhaust port 41. As a result, the air in the air lock chamber 34 is exhausted (or leaked).

  A base (Y) 43 is attached to the base flange 32 via a Y-axis linear guide 42. At both ends, a Y-axis linear actuator 44 fixed to the base flange 32 and a preload pressing spring 45a are provided to move the base (Y) 43 in the Y-axis direction.

  Similarly, a base (Z) 47 is attached to the base (Y) 43 via a Z-axis linear guide 46. The base (Y) 43 is fixed by a Z-axis linear actuator 48 fixed to the base (Y) 43 and a preload pressing spring 45b. , In the Z-axis direction. The base (X) 50 is moved along the X-axis linear guide 49 in the X-axis direction. At this time, the output of the X-axis linear actuator 51 is inverted using the lever 55.

  Since the air lock chamber 32 and the probe holder 54 on which the probe 36 is mounted are fixed to the base (X) 50, the linear actuators 44, 48, 51 of each axis are driven so that the probe 36 You can move. The position of the probe 36 is grasped by the output values of the encoders 52a, 52b, 52c of each axis, and highly accurate position control is possible. The probe holder 54 is provided with a shaft vacuum seal 53 so as to be movable along the axis of the airlock chamber 32 while maintaining a vacuum.

  Here, the operation of the present embodiment will be described. When replacing the probe 36, as shown in FIG. 6A, the probe holder 54 is manually retracted, the valve opening / closing mechanism 38 is operated, and the vacuum valve 37 is closed. As a result, the air lock chamber 34 becomes a separate space from the main body vacuum chamber 31. Here, air is introduced into the air lock chamber 34 from the exhaust port 41 to make the inside of the air lock chamber 34 atmospheric pressure.

  Thereafter, the probe holder 54 is further pulled out from the airlock chamber 34, and the probe 36 is replaced after the state shown in FIG. 6B. After the replacement, it may be incorporated in the reverse procedure. First, the probe holder 36 is inserted into the airlock chamber 34, and the inside of the airlock chamber 34 is evacuated. After confirming that the pressure difference between the air lock chamber 34 and the vacuum chamber 31 has disappeared, the valve opening / closing mechanism 38 is operated to open the vacuum valve 37. The probe holder 54 is further manually inserted into the vacuum chamber 31. To operate the probe 36 at a desired position, the airlock chamber 34 is moved together with the three-axis linear actuators 44, 48, 51. Thus, the probe can be replaced without exposing the vacuum chamber to the atmosphere.

  FIG. 7 is a schematic diagram when the embodiment of the present invention is applied to a probe device. In the drawing, an electron beam 72 emitted from an electron gun 71 is shaped by an aperture 73, the spread of the electron beam 72 is controlled by a focusing lens 74, Is focused at the position. A substrate 78 such as a semiconductor wafer or a semiconductor chip is placed on the stage 77, and the position of an element to be evaluated on the substrate 78 is specified by a stage position controller 79.

  Each of the probes 81a, 81b, 81c mounted on the plurality of manipulators 80a, 80b, 80c is moved to the position of the evaluation element on the substrate 78 by the probe position controllers 82a, 82b, 82c which can be driven independently of the stage 77. Move. At the time of movement, the electron beam 72 is scanned by the electron beam controller 83 near the evaluation element on the substrate 78, secondary electrons from the substrate 78 are detected by the secondary electron detector 84, and the image is displayed on the display 85. Perform while displaying / observing. A power supply 86 is connected to each of the probes 81a, 81b, and 81c so that a voltage can be applied to a minute portion of the substrate 78 in contact with the probe. At the same time, an ammeter 87 is connected so that the current flowing through each of the probes 81a, 81b, 81c can be measured.

  As an example of the evaluation method, a case of a MOS device formed on a wafer will be described. First, three probes are brought into contact with a source electrode, a gate electrode, and a drain electrode, respectively. Here, the source electrode is grounded using a probe, and the probe measures the relationship between the drain voltage and the drain current flowing between the source and the drain while varying the voltage of the gate electrode as a parameter. Thereby, the output characteristics of the MOS can be obtained. These operations are collectively controlled by the central processing unit 88.

  The manipulators 80a, 80b, 80c have the same configuration as that shown in FIG. Thereby, even if the probe is broken at the time of measurement evaluation, the probe can be easily replaced, so that the operation rate of the probe device can be improved.

  Further, in the present embodiment, even with a probe device using an irradiation optical system configured by replacing the electron gun 71 with an ion source, a similar effect can be obtained by using the manipulator of the present invention.

  FIG. 8 is a schematic diagram when the embodiment of the present invention is applied to a sample preparation apparatus. In the drawing, an ion beam 90 emitted from an ion source 89 is shaped by a beam limiting aperture 91, the spread of the ion beam 90 is controlled by a focusing lens 74, and is passed on a stage 77 by passing through a deflector 75 and an objective lens 76. At a desired position.

  The focused ion beam (FIB) 90 can perform precise processing of the sample 92 by sputtering the surface of the substrate 78 into a scanned shape. On the stage 77, a substrate 78 such as a semiconductor wafer or a semiconductor chip and a sample holder 93 for holding an extracted sample 92 are mounted, and a stage position controller 79 specifies a position for processing and extracting the sample. . The probe 81 mounted on the manipulator 80 is moved to an extraction position on the substrate 78 by a probe position controller 82 that can be driven independently of the stage 77. At the time of movement and processing, the FIB controller 94 scans the FIB near the extraction position of the substrate 78, detects secondary electrons from the substrate 78 by the secondary electron detector 84, and displays the image on the display 85. / Perform while observing.

  In extracting the sample 92, the sample 92 is cut out in a wedge shape by performing FIB processing while changing the posture of the substrate 78, and the tip of the probe 81 is brought into contact with the sample 92. The probe 81 and the sample 92 are bonded to each other by supplying a deposition gas to the contact portion by using a deposition gas source 95 and forming an ion beam assisted deposition film.

  Thereafter, the probe 81 is pulled up from the substrate 78 by the probe position controller 82 and moved to the position of the sample holder 93 on the stage 77. The probe 81 is lowered, and it is confirmed that the wedge tip of the sample 92 adhered to the probe 81 is in contact with the surface of the sample holder 93, and the side surface of the sample 92 and the sample holder 93 are adhered by the ion beam assisted deposition film. . The tip of the probe 81 is cut from the sample 92 by the FIB, and is moved to the next sample extracting position by the probe position controller 82. In this way, it is possible to transfer a desired number of samples from one substrate to one sample holder.

  These operations are collectively controlled by the central processing unit 88. Note that the manipulator has the configuration shown in FIG. 3 as in the above-described embodiment. Accordingly, even if the probe is worn or damaged, the probe can be easily replaced, so that the operation rate of the sample manufacturing apparatus can be improved.

  FIG. 9 is a schematic diagram when the embodiment of the present invention is applied to a sample observation device. In the drawing, an ion beam 90 emitted from an ion source 89 is shaped by a beam limiting aperture 91, the spread of the ion beam 90 is controlled by a focusing lens 74, and is passed on a stage 77 by passing through a deflector 75 and an objective lens 76. At a desired position. The focused ion beam 90, that is, FIB, can be precisely processed by sputtering the surface of the substrate 78 into a scanned shape.

  A substrate 78 such as a semiconductor wafer or a semiconductor chip is mounted on the stage 77, and a position for observing the substrate is specified by a stage position controller 79. The probe 81 mounted on the manipulator 80 is moved to an observation position on the substrate 78 by a probe position controller 82 that can be driven independently of the stage 77.

  At the time of movement and processing, the FIB controller 94 scans the FIB at the observation position of the substrate 78, detects secondary electrons from the substrate 78 by the secondary electron detector 84, and displays the image on the display 85. While doing. A power supply 86 is connected to the probe 81 so that a voltage can be applied to a minute portion of the substrate 78 in contact therewith.

  When performing observation, first, a groove is formed around the circuit by FIB so that the circuit to be observed is electrically isolated from other circuits. A probe 81 to which a voltage has been applied is brought into contact with one end of the circuit, and a portion that would be connected to the circuit by design is observed. If the connection is made without disconnection, the contrast changes (brightens), so that it is possible to judge the circuit failure.

  These operations are collectively controlled by the central processing unit 88. Note that the manipulator has the configuration shown in FIG. 3 as in the above-described embodiment. Thus, even if the probe is damaged, the probe can be easily replaced, and the operation rate of the sample observation device can be improved.

1 is a schematic vertical sectional view of a manipulator according to one embodiment of the present invention. FIG. 6 is an explanatory diagram of the operation of the manipulator according to one embodiment of the present invention. It is a longitudinal section of a manipulator of another example of the present invention. FIG. 4 is a plan view of the manipulator of the embodiment of FIG. FIG. 4 is a sectional view taken along the line AA of the manipulator of the embodiment in FIG. 3. FIG. 4 is an operation explanatory diagram of the manipulator of the embodiment in FIG. 3. It is a principal part perspective view of the probe apparatus of another Example of this invention. It is a principal part perspective view of the sample preparation apparatus of another Example of this invention. It is a principal part perspective view of the sample observation apparatus of another Example of this invention.

Explanation of reference numerals

  DESCRIPTION OF SYMBOLS 1 ... Vacuum chamber, 2 ... Vacuum bellows, 3 ... Air lock chamber, 4 ... Probe, 5 ... Probe holder, 6 ... Vacuum seal, 7 ... 3-axis moving mechanism, 8 ... Vacuum valve, 9 ... Exhaust port, 10 ... 1 Shaft moving mechanism, 31: vacuum chamber, 32: base flange, 33: vacuum seal, 34: air lock chamber, 35: vacuum bellows, 36: probe, 37: vacuum valve, 38: valve opening / closing mechanism, 39: exhaust pipe , 40 ... vacuum bellows, 41 ... exhaust port, 42 ... Y-axis linear guide, 43 ... base (Y), 44 ... Y-axis linear actuator, 45 ... preload press spring, 46 ... Z-axis linear guide, 47 ... Base (Z), 48 ... Z-axis linear actuator, 49 ... X-axis linear guide, 50 ... Base (X), 51 ... X-axis linear actuator, 52 ... Encoder, 3: vacuum seal, 54: probe holder, 55: lever, 71: electron gun, 72: electron beam, 73: aperture, 74: focusing lens, 75: deflector, 76: objective lens, 77: stage, 78: substrate 79, stage position controller, 80, manipulator, 81, probe, 82, probe position controller, 83, electron beam controller, 84, secondary electron detector, 85, display, 86, power supply, 87, ammeter, 88 Central processing unit, 89: ion source, 90: ion beam, 91: beam limiting aperture, 92: sample, 93: sample holder, 94: FIB controller, 95: deposit gas source.

Claims (1)

  A manipulator comprising a needle-like member and a moving means for moving the needle-like member in a vacuum container, wherein the needle-like member is moved in and out of the vacuum container without opening the vacuum container to the atmosphere. A manipulator comprising a vacuum introducing means capable of performing the following.

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