JP4300211B2 - manipulator - Google Patents

Description

  The present invention relates to a microprobe manipulator in a vacuum, and in particular, a part necessary for analysis and observation from a sample piece using a probe device for evaluating the performance of an electronic element or analyzing a defect, or using a focused ion beam. The present invention relates to a sample preparation device that processes and extracts only the sample.

  There is a prober as a conventional evaluation method for electronic devices. This is a method in which a probe is brought into contact with a position where electrical characteristics are to be measured while observing a test 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 identify a conduction failure point.

  In recent years, with the progress of high integration of semiconductors, a method for evaluating an electronic element having submicron wiring has been devised. For example, as disclosed in Patent Document 1, in the prober described above, instead of an optical microscope, a microscopic means (such as an electron microscope) that irradiates a sample with charged particles in a vacuum and detects secondary electrons. The probe is brought into contact with the sample by a highly accurate probe moving mechanism.

  In addition, with the high integration of semiconductors, the need for analysis in 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) with high observation resolution is considered promising instead of SEM. In order to observe with TEM, it is necessary to process the thickness of the observation part of a sample thinly to 0.1 micrometer. 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. During TEM observation, this thin wall surface is irradiated with an electron beam perpendicularly.

  The disadvantages of this method are that it takes a lot of work to prepare a single sample, and there are places that cannot be analyzed for cutting the wafer.

  On the other hand, Patent Document 2 discloses the following method. In this method, the sample is cut out only by FIB processing while changing the posture of the sample. Here, as the sample extraction means after cutting, the operation needle having the same shape as the probe of the prober described above is brought into contact with the sample, the deposition gas is supplied, and the ion beam assisted deposition film is formed, thereby the operation needle And the sample are bonded to each other 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 the probe tip or the operation needle (hereinafter referred to as a probe) is brought into contact with the sample, which causes deterioration of the probe tip. A contact detection method for making the load / displacement such that the deformation of the probe when brought into contact with the sample is within the elastic deformation region is also being studied. However, since the surface of the sample 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 probe contact detection failure. As a result, the probe tip is plastically deformed, making it difficult to use the probe after the next time. This problem becomes more prominent as the degree of semiconductor integration increases and the probe tip becomes thinner.

  Speaking only of the latter sample preparation apparatus, the probe tip must be cut when another sample is prepared and extracted after the probe tip is bonded to the sample and the sample is separated from the wafer. This cutting can be performed by FIB, and the cutting surface can be sharpened by FIB. However, since it is only flat processing, the probe becomes thick and wedge-shaped in the thickness direction. For this reason, there are limits to repeated use.

  For the above reasons, the probe is a consumable item in any of the devices, and needs to be replaced with considerable frequency. By the way, in the probe moving manipulator attached to these devices, the mechanism portion and the probe are integrated, and when replacing the probe, the vacuum chamber must be opened to the atmosphere and removed from the main body. For this reason, in starting up the vacuum after replacement, a long time is required, which causes a reduction in the operating 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 without removing the vacuum chamber from the atmosphere when the probe is taken in and out of the vacuum chamber as the apparatus main body. Specifically, an air lock chamber is provided in the vacuum chamber, and this air lock chamber is connected to the vacuum chamber of the main body by a flexible vacuum bellows. The member holding the probe is attached to the air lock chamber, and the probe can be moved together with the air lock chamber by a moving mechanism provided in the main body. The air lock chamber can be evacuated, and the air lock chamber and the vacuum chamber are partitioned by a vacuum valve. A second moving mechanism is provided so that the probe can move between the air lock chamber and the vacuum chamber.

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

  FIG. 1 is a schematic configuration diagram of a manipulator showing an embodiment of the present invention. In the figure, an air lock chamber 3 connected by a vacuum bellows 2 is provided in a vacuum chamber 1 which is an apparatus main body. The probe holder 5 to which the probe 4 is attached is fixed to the air lock chamber 3 through a vacuum seal 6, and the entire air lock chamber 3 is probed by three-axis moving mechanisms 7 a, 7 b, 7 c provided in the vacuum chamber 1. 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 / open to the atmosphere from the exhaust port 9. The probe holder 5 is provided with a uniaxial moving mechanism 10 so that the probe 4 can move between the air lock chamber 3 and the vacuum chamber 1.

  Here, the operation of the present embodiment will be described. When the probe 4 is replaced, as shown in FIG. 2A, the probe holder 5 is retracted using the moving mechanism 10 and the vacuum valve 8 is closed. As a result, 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 air lock chamber 3 atmospheric pressure. Thereafter, the probe holder 5 is removed from the air lock chamber 3, and the probe 4 is replaced after the state shown in FIG. After replacement, the probe holder 5 is attached to the air lock chamber 3 in the reverse procedure, and the air lock 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. In order to operate the probe 4 to a desired position, the air lock chamber 3 is moved using the triaxial moving mechanisms 7a, 7b and 7c. As a result, the probe can be replaced without opening the vacuum chamber to the atmosphere.

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

  In the figure, a base flange 32 is fixed to a vacuum chamber 31 which is an apparatus main body 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 the end surface of the air lock chamber 34. The vacuum valve 37 is opened and closed by rotating a cylindrical valve opening / closing mechanism 38 configured in the air lock chamber 34. In the air lock chamber 34, an exhaust pipe 39 is attached to the base flange 32 through a vacuum bellows 40 and communicates with the exhaust port 41. Thereby, exhaust (or leak) in the air lock chamber 34 is performed.

  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 and a preload pressing spring 45a fixed to the base flange 32 are set, and the base (Y) 43 is moved in the Y-axis direction.

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

  Since the air lock chamber 32 and the probe holder 54 to which the probe 36 is attached are fixed to the base (X) 50, the linear actuators 44, 48, 51 of each axis are driven to drive the probe 36. Can move. The position of the probe 36 is grasped by the output values of the encoders 52a, 52b, and 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 shaft of the air lock chamber 32 while maintaining a vacuum.

  Here, the operation of the present embodiment will be described. When the probe 36 is replaced, 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 is separated from the main body vacuum chamber 31. Here, air is introduced into the air lock chamber 34 from the exhaust port 41 to bring the air lock chamber 34 to atmospheric pressure.

  Thereafter, the probe holder 54 is further pulled out of the air lock chamber 34 and the probe 36 is replaced after the state shown in FIG. After replacement, it can be installed in the reverse order. First, the probe holder 36 is inserted into the air lock chamber 34 and the air lock 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. In order to operate the probe 36 to a desired position, the air lock chamber 34 is moved using the triaxial linear actuators 44, 48 and 51. As a result, the probe can be replaced without opening the vacuum chamber to the atmosphere.

  FIG. 7 is a schematic view when the embodiment of the present invention is applied to a probe apparatus. In the figure, 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 converging lens 74, and passes through a deflector 75 and an objective lens 76 so as to be desired on a stage 77. It is focused on 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 probe 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 a probe position controller 82a, 82b, 82c that can be driven independently of the stage 77. Move. During the movement, the electron beam controller 83 scans the electron beam 72 in the vicinity of the evaluation element of the substrate 78, the 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 source 86 is connected to each of the probes 81a, 81b, 81c so that a voltage can be applied to a minute portion of the substrate 78 that is in contact. At the same time, an ammeter 87 is connected so that the current flowing through the probes 81a, 81b, 81c can also 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 the source electrode, the gate electrode, and the drain electrode, respectively. Here, the source electrode is dropped to the ground using a probe, and the relationship between the drain voltage and the drain current flowing between the source and the drain is measured by the probe while swinging the voltage of the gate electrode as a parameter by the probe. 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, and 80c have the same configuration as that shown in FIG. As a result, even if the probe is damaged during measurement evaluation, the probe can be easily replaced, so that the operating rate of the probe device can be improved.

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

  FIG. 8 is a schematic view when the embodiment of the present invention is applied to a sample preparation apparatus. In the figure, 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 passes on a stage 77 by passing through a deflector 75 and an objective lens 76. To the desired position.

  The focused ion beam (FIB) 90 can perform a 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 the extracted sample 92 are placed, and the stage position controller 79 specifies the position where the sample is processed and extracted. . The probe 81 attached to 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. During movement and processing, the FIB controller 94 scans the FIB in the vicinity of 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.

  The sample 92 is extracted by performing FIB processing while changing the posture of the substrate 78, so that the sample 92 is cut into a wedge shape and the tip of the probe 81 is brought into contact with the sample 92. A deposition gas is supplied to the contact portion using a deposition gas source 95 to form an ion beam assisted deposition film, thereby bonding the probe 81 and the sample 92 together.

  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, 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 with an ion beam assisted deposition film. . The tip of the probe 81 is cut from the sample 92 by FIB, and moved to the next sample extraction 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. As in the above-described embodiment, the manipulator has the configuration shown in FIG. Accordingly, even if the probe is consumed or damaged, the probe can be easily exchanged, so that the operating rate of the sample preparation apparatus can be improved.

  FIG. 9 is a schematic view when the embodiment of the present invention is applied to a sample observation apparatus. In the figure, 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 passes on a stage 77 by passing through a deflector 75 and an objective lens 76. To the 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 placed on the stage 77, and the position where the substrate is observed 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.

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

  When observing, 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 is applied is brought into contact with one end of the circuit, and a portion that will be connected to the circuit by design is observed. If it is connected without disconnection, the contrast changes (becomes brighter), so that it is possible to determine a circuit failure.

  These operations are collectively controlled by the central processing unit 88. As in the above-described embodiment, the manipulator has the configuration shown in FIG. As a result, even if the probe is broken, it is possible to easily replace the probe and to improve the operating rate of the sample observation apparatus.

It is a schematic longitudinal cross-sectional view of the manipulator of one Example of this invention. It is operation | movement explanatory drawing of the manipulator of one Example of this invention. It is a longitudinal cross-sectional view of the manipulator of another Example of this invention. It is a top view of the manipulator of the Example of FIG. It is AA sectional drawing of the manipulator of the Example of FIG. It is operation | movement explanatory drawing of the manipulator of the Example of FIG. 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 symbols

  DESCRIPTION OF SYMBOLS 1 ... Vacuum chamber, 2 ... Vacuum bellows, 3 ... Air lock chamber, 4 ... Probe, 5 ... Probe holder, 6 ... Vacuum seal, 7 ... Triaxial moving mechanism, 8 ... Vacuum valve, 9 ... Exhaust port, 10 ... 1 Axis 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 piping 40 ... Vacuum bellows, 41 ... Exhaust port, 42 ... Linear guide for Y axis, 43 ... Base (Y), 44 ... Linear actuator for Y axis, 45 ... Preload spring, 46 ... Linear guide for Z axis, 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 source, 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 ... Depot gas source.

Claims (7)

A probe in contact with the sample;
A probe holder for holding the probe;
A first moving mechanism for moving the probe to a desired position of the sample in a vacuum chamber;
An airlock chamber connected to the vacuum chamber;
A vacuum valve that opens and closes between the vacuum chamber and the air lock chamber,
The probe holder is held in the air lock chamber,
The first moving mechanism is a manipulator that moves the probe together with the airlock chamber. The manipulator according to claim 1, wherein
The first movement mechanism is a manipulator that is a movement mechanism capable of driving at least two axes. A probe in contact with the sample;
A probe holder for holding the probe;
A three-axis first moving mechanism for moving the probe to a desired position of the sample in a vacuum chamber;
An airlock chamber connected to the vacuum chamber;
A vacuum valve that opens and closes between the vacuum chamber and the air lock chamber,
The air lock chamber can be evacuated from the exhaust port and released to the atmosphere independently of the vacuum chamber.
The first moving mechanism is a manipulator that moves the probe together with the airlock chamber. In a manipulator that moves a probe in a vacuum chamber of a charged particle beam apparatus having at least a sample stage on which a sample is placed,
A probe holder for holding the probe;
A first moving mechanism for moving the probe to a desired position of the sample in a vacuum chamber;
An airlock chamber connected to the vacuum chamber;
A vacuum valve that opens and closes between the vacuum chamber and the air lock chamber,
The probe holder is held in the air lock chamber,
The first moving mechanism is a manipulator that moves the probe together with the airlock chamber. The manipulator according to any one of claims 1 to 4,
The probe holder is provided with a uniaxial second moving mechanism,
The second moving mechanism is a manipulator that moves the probe between the air lock chamber and the vacuum chamber. An airlock chamber connected to the vacuum chamber;
A vacuum valve disposed between the vacuum chamber and the air lock chamber, for opening and closing between the vacuum chamber and the air lock chamber;
A first moving mechanism for moving the air lock chamber;
When the air lock chamber is evacuated and the vacuum valve is open, a probe introduced into and out of the vacuum chamber;
A probe holder for holding the probe;
A second moving mechanism for moving the probe,
The probe holder is held in the air lock chamber,
The manipulator in which the probe can be moved to a desired position of the sample in the vacuum chamber by the first moving mechanism, and the probe moves together with the air lock chamber. The manipulator according to any one of claims 1 to 6,
The air lock chamber is a manipulator that moves along a guide provided in the vacuum chamber.

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