JP2007071740A - Charged particle beam device equipped with manipulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manipulator for charged particle beams which implements exchanging work for a probe of manipulator quickly, keeping vacuum. <P>SOLUTION: After a probe mount 32 is moved to move a used probe 27 to a probe exchange position 20, a probe holder 34 is rotated if needed, and then an empty probe storage section 35 is moved to the probe exchange position 20. Next, the used probe 27 is removed from a probe fixing plated spring 29 to put in an empty probe storage section 35. The probe holder 34 is rotated to move the probe storage section 35a containing an unused probe 27a to the probe exchange position 20. Finally, by bring the unused probe 27a out from the probe storage plated spring 30 to load on the probe fixing plated spring 29, the probe exchanging is completed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a charged particle beam apparatus such as a scanning electron microscope equipped with a manipulator, and more particularly to a probe exchange mechanism used when measuring electrical characteristics of a sample with the manipulator.

  2. Description of the Related Art Some charged particle beam devices such as a scanning electron microscope include a manipulator having a probe (probe) in a sample chamber, and measures the electrical characteristics of the sample by applying a voltage or the like to the sample arranged in the sample chamber. An example of a conventional scanning electron microscope having such a configuration is shown in FIG. FIG. 1 is a cross-sectional view showing a schematic configuration of a sample chamber of a scanning electron microscope and its surroundings in the prior art. In FIG. 1, the electron beam EB is narrowed down by the objective lens 2 and applied to the sample 15 placed on the sample holder 14. Note that a lens barrel including an electron gun, a focusing lens scanning coil, and the like is not shown.

  The inside of the sample chamber 1 is kept in a vacuum, and a sample stage 5 having a Z-axis moving / tilting mechanism is attached to the wall of the sample chamber 1. On the sample stage 5, a Y-axis moving stage 6 and an X-axis moving stage 7 for performing a wide range of sample movement are configured. Here, the vertical relationship between the Y-axis moving stage 6 and the X-axis moving stage 7 has no particular meaning. A manipulator 18 is placed on the X-axis moving stage 7. The manipulator 18 includes a manipulator base 8 and an X-axis moving mechanism 9, a Y-axis moving mechanism 10, a Z-axis moving mechanism 11, a probe mount 12, a probe support member 13, and a probe 17 for each probe. . Here, the vertical relationship among the X-axis moving mechanism 9, the Y-axis moving mechanism 10, and the Z-axis moving mechanism 11 has no particular meaning. A lead wire (not shown) is wired to the probe 17 so that an electric signal can be taken out of the vacuum through an airtight terminal (not shown) provided on the wall of the sample chamber 1. The sample holder 14 is also placed on the manipulator base 8.

  A preliminary exchange chamber 3 is attached to the sample chamber 1, and a vacuum gate valve 4 is provided between the preliminary exchange chamber 3 communicating with the sample chamber 1. The inside of the sample chamber 1 and the preliminary exchange chamber 3 can be individually switched between vacuum holding and atmospheric release by an evacuation system (not shown). The spare exchange chamber 3 is provided with a replacement shaft 16 for moving the manipulator 18 between the spare exchange chamber 3 and the sample chamber 1. FIG. 2 is a plan view when the sample chamber and its periphery in the prior art of FIG. 1 are viewed from above (objective lens 2 side). Although FIG. 2 shows a case where four probes for measuring the electrical characteristics of the sample are provided, the number of probes varies depending on the purpose of measurement. For example, when measuring an internal electromotive force generated when an electron beam irradiated to a sample flows to the ground, at least two probes are required to measure a voltage between any two points. Further, for example, in the four-terminal method using four probes, a DC voltage is applied between two probes brought into contact with both ends of the sample, and the other two probes are placed on the desired two points on the sample. The resistance of the sample is measured by measuring the voltage drop between the two points.

  When it is necessary to replace the probe due to deformation or wear of the probe tip due to the measurement, the manipulator 18 is moved to the preliminary replacement chamber 3. The exchange is performed according to the following procedure. First, the preliminary exchange chamber 3 is brought into a vacuum state, the vacuum gate valve 4 is opened, the tip of the exchange shaft 16 is moved into the sample chamber, and is connected to the manipulator base 8. When the exchange shaft 16 is moved to the spare exchange chamber 3 side, the manipulator base 8 moves to the spare exchange chamber 3 with the manipulator 18 and the sample holder 14 placed thereon, as shown in the plan view of FIG. If the vacuum gate valve 4 is closed again and only the preliminary exchange chamber 3 is opened to the atmosphere, the probe can be exchanged. As is clear from the above procedure, the same procedure as the probe replacement is performed when only the sample replacement is necessary.

JP 2000-251820 A JP 2005-26530 A

  A semiconductor is mainly used as a sample for measuring electrical characteristics. However, as the degree of integration with LSI and VLSI increases on a large scale and the density increases, the part where the probe is brought into contact with becomes smaller. For this reason, the tip of the probe used for measurement is made extremely thin, and since it is easily deformed and worn, the probe replacement frequency must be increased. However, in the prior art shown in FIGS. 1 to 3, there is a problem that it takes time to replace the probe because it is necessary to take out the probe together with the manipulator when replacing the probe used in a high vacuum.

  In order to solve such a problem, Japanese Patent Application Laid-Open No. 2000-251820 of Patent Document 1 is provided with a probe holder dedicated air lock chamber, and a probe holding member is attached to the air lock chamber so that each probe can move. In the probe replacement, a technique is disclosed in which the probe is moved to the air lock chamber and the replacement operation is performed in the air lock chamber opened to the atmosphere. According to this technique, by providing a plurality of probe-dedicated airlock chambers, it is possible to measure the electrical characteristics of a sample using a plurality of probes, and it is possible to perform probe replacement while maintaining the vacuum of the main body. However, since an air lock chamber dedicated to the probe holder must be provided for each probe, there is a problem that the structure of the apparatus becomes complicated and the cost increases.

  Japanese Patent Application Laid-Open No. 2005-26530 of Patent Document 2 discloses a technique that uses a sample holder moving mechanism and a manipulator moving mechanism for exchanging samples. According to this technique, since an air lock chamber dedicated to the probe holder is not required, a simple configuration can be achieved. In addition, the probe of the manipulator can be exchanged efficiently while maintaining the vacuum of the main body. However, since the air lock chamber is also used for sample exchange, there is a problem that measurement using a plurality of probes cannot be performed.

  The present invention is provided with a manipulator that solves the above-mentioned problems, can measure the electrical characteristics of a sample using a plurality of probes, and can replace a probe that has been consumed in a short time with a new probe while maintaining the vacuum of the main body. It is to provide a charged particle beam apparatus.

In order to solve the above problems, the present invention provides:
A charged particle having a moving mechanism capable of moving the sample holder between the sample chamber and a preliminary exchange chamber communicating with the sample chamber, and a manipulator for holding and moving the probe contacting the sample on the sample holder. In the beam device,
A probe holder provided on the manipulator for removably supporting the probe; a probe holder having a first probe storage section for storing a used probe; and a second probe storage section for storing an unused probe;
The probe support means, the first probe storage portion, and the second probe storage portion are composed of a pair of leaf springs facing each other, and an interval between the pair of leaf spring tips facing each other across the probe is It is configured to be wider than the distance between the pair of leaf spring tips facing each other that do not sandwich the probe,
In a state where the vacuum in the sample chamber is maintained, the probe support means is associated / separated with respect to the first or second probe storage portion, thereby removing the used probe from the probe support means. The probe is stored in one probe storage section, and the unused probe is taken out from the second probe storage section and attached to the probe support means.

  In the invention, it is preferable that the probe holder is movable between the sample exchange chamber and the preliminary exchange chamber by the movement mechanism.

  Further, the present invention is characterized in that the sample can be placed on the probe holder.

  Further, the present invention is characterized in that the first probe storage portion and the second probe storage portion are arranged in the vicinity of the outer periphery on the probe holder.

  According to the present invention, there is provided means for moving the first probe storage portion and the second probe storage portion to a position for removing and attaching the used probe and the unused probe to and from the probe support means. The means for rotating the sample holder with the center of the sample holder as the center of rotation.

  Further, the present invention is characterized in that the probe is formed so as to become thinner from the body portion toward an end portion where the probe tip portion is supported and an end portion on the opposite side thereof.

According to the present invention,
A charged particle having a moving mechanism capable of moving the sample holder between the sample chamber and a preliminary exchange chamber communicating with the sample chamber, and a manipulator for holding and moving the probe contacting the sample on the sample holder. In the beam device,
A probe holder provided on the manipulator for removably supporting the probe; a probe holder having a first probe storage section for storing a used probe; and a second probe storage section for storing an unused probe;
The probe support means, the first probe storage portion, and the second probe storage portion are composed of a pair of leaf springs facing each other, and an interval between the pair of leaf spring tips facing each other across the probe is It is configured to be wider than the distance between the pair of leaf spring tips facing each other that do not sandwich the probe,
In a state where the vacuum in the sample chamber is maintained, the probe support means is associated / separated with respect to the first or second probe storage portion, thereby removing the used probe from the probe support means. Since the unused probe is taken out from the second probe storage portion and attached to the probe support means,
Even a manipulator capable of measuring electrical characteristics of a sample using a plurality of probes can replace a used probe with an unused probe in a short time while maintaining the vacuum of the main body. Therefore, the measurement efficiency can be greatly improved. Also, when replacing samples and when only used probes are stored in the probe holder and they are replaced with new probes, it is only necessary to open the sample holder to the atmosphere, thus eliminating the need for a large spare replacement chamber and reducing manufacturing costs. The operability can be improved.

Embodiments of the present invention will be described below with reference to the drawings. In addition, this Example is an example and this invention is not necessarily limited to this.
FIG. 4 is a longitudinal sectional view showing a schematic configuration of the sample chamber of the scanning electron microscope and its periphery in the present invention. In FIG. 4, the electron beam EB is narrowed down by the objective lens 2 and applied to the sample 15 placed on the probe holder 34. As in FIG. 1, a lens barrel made up of an electron gun, a focusing lens scanning coil, and the like is not shown.

  The inside of the sample chamber 31 is kept in a vacuum, and a sample stage 5 having a Z-axis moving / tilting mechanism is attached to the wall of the sample chamber 31. On the sample stage 5, a Y-axis moving stage 6 and an X-axis moving stage 7 for performing a wide range of sample movement are configured. Here, the vertical relationship between the Y-axis moving stage 6 and the X-axis moving stage 7 has no particular meaning. A manipulator 38 is placed on the X-axis moving stage 7. The manipulator 38 includes a manipulator base 8 and an X-axis moving mechanism 9, a Y-axis moving mechanism 10, a Z-axis moving mechanism 11, a probe mount 32, a leaf spring support member 33, and a probe 27 for each probe. Yes. Here, the vertical relationship among the X-axis moving mechanism 9, the Y-axis moving mechanism 10, and the Z-axis moving mechanism 11 has no particular meaning. A lead wire (not shown) is wired to the probe 27 so that an electric signal can be taken out of the vacuum through an airtight terminal (not shown) provided on the wall of the sample chamber 31. The probe holder 34 is placed on the manipulator base 8. A sample 15 is placed on the probe holder 34, and a plurality of probe storage portions 35 are attached so as to surround the sample 15. The probe storage unit 35 is provided to store a used probe and a replacement unused probe. A rotation mechanism 25 that rotates the probe holder 34 around the center of the probe holder 34 is provided below the probe holder 34.

  FIG. 8A shows an enlarged perspective view of the vicinity of the probe 27. The probe 27 is sandwiched so as to be detachable by a probe fixing leaf spring 29 supported by a leaf spring supporting member 33, and is fixed in a state where the electrical characteristics of the sample 15 can be measured. FIG. 8B is a perspective view showing a state in which the probe 27 is stored in the probe storage portion 35. The probe storage leaf spring 30 holds the probe 27 so as to be detachable. The probe tip 28 is accommodated in a probe tip accommodation hole 34 a formed in the probe holder 34. The probe distal end portion 28 side and the opposite end portion of the probe 27 are formed so as to become narrower from the body portion toward the end in order to smoothly perform probe exchange described later.

  A preliminary exchange chamber 23 is attached to the sample chamber 31, and a vacuum gate valve 24 is provided between the preliminary exchange chambers 23 communicating with the sample chamber 31. The inside of the sample chamber 31 and the preliminary exchange chamber 23 can be individually switched between vacuum holding and atmospheric release by an evacuation system (not shown). The spare exchange chamber 23 is provided with an exchange shaft 26 for moving the probe holder 34 between the spare exchange chamber 23 and the sample chamber 31.

  FIG. 5 is a plan view of the sample chamber and its periphery in FIG. 4 as viewed from above (from the objective lens 2 side). FIG. 5 shows a case where four probes for measuring the electrical characteristics of the sample are provided, but the number of probes varies depending on the purpose of measurement, and the present invention is not limited to this.

  Next, a method for exchanging the probe 27 in which the probe tip 28 is deformed and worn by measurement in the vacuum of the sample chamber 31 will be described. FIG. 7 is a diagram showing the concept of a method for exchanging probes. A probe replacement position 20 for a certain probe is determined. At the probe replacement position 20, the directions of the two leaf springs facing each other, that is, the probe fixing leaf spring 29 supported by the leaf spring support member 33 and the probe housing leaf spring 30 attached to the probe housing portion 35 are matched. It has become. However, the orientations of the probe holders in FIG. 7 are all drawn in the direction seen from the direction of arrow A in FIG.

  An outline of the probe replacement procedure will be described with reference to FIG. First, the probe mount 32 is moved and the probe 27 is set at the probe replacement position 20. The probe holder 34 is rotated as necessary to move the empty probe storage portion 35 to the probe replacement position 20. FIG. 7A shows the state at this time. Next, the used probe 27 is removed from the probe fixing plate spring 29 and stored in an empty probe storage section 35, and the probe holder 34 is rotated to probe the probe storage section 35a in which the unused probe 27a is stored. Move to exchange position 20. FIG. 7B shows the state at this time. Next, the unused probe 27a is taken out from the probe storage portion 35a and attached to the probe fixing leaf spring 29, and the probe replacement is completed.

  Details of the probe exchange method will be described with reference to FIG. FIG. 9A shows a method for transferring the used probe 27 to the empty probe storage unit 35. In FIG. 9A, the distance between the two leaf spring tips facing each other of the probe fixing leaf spring 29 sandwiching the probe 27 is the distance between the two leaf spring tips facing each other of the probe storage leaf spring 30 not sandwiching the probe 27. It is wider than the interval. Therefore, when the probe fixing plate spring 29 and the probe storage plate spring 30 are brought into association with each other and the probe mount 32 is lowered, the tip of the probe storage plate spring 30 is moved from the tip of the probe fixing plate spring 29 to the probe 27 and the probe storage plate spring 29. I will cut in between. After the probe storage leaf spring 30 has completely sandwiched the probe 27, the probe mount 32 is raised to separate the probe fixing plate spring 29 and the probe storage leaf spring 30, thereby completing the removal and storage of the probe.

  FIG. 9B shows a method for moving the unused probe 27a to the probe mount 32 side. In FIG. 9B, the distance between the two leaf spring tips facing each other of the probe storage leaf spring 30 sandwiching the probe 27a is the distance between the two leaf spring tips facing each other of the probe fixing leaf spring 29 not sandwiching the probe 27a. It is wider than the interval. Therefore, when the probe fixing plate spring 29 and the probe storage plate spring 30 are brought into association with each other and the probe mount 32 is lowered, the tip of the probe fixing plate spring 29 is inserted between the probe 27 a and the plate spring from the tip of the probe storage plate spring 30. Go. When the probe fixing plate spring 29 completely sandwiches the probe 27a, the probe mount 32 is raised and the probe fixing plate spring 29 and the probe storage plate spring 30 are separated from each other, the removal and mounting of the probe are completed.

  Here, for example, as can be seen from FIG. 9A, the tips of the two leaf springs 30 facing each other not sandwiching the probe 27 are inside the tips of the two leaf springs 29 facing each other sandwiching the probe 27. The probe tip 28 side of the probe 27 and the opposite end thereof are connected to the body so that the tip of the plate spring 30 to be interrupted smoothly enters when entering between the plate spring 29 and the probe 27. It is formed so as to become thinner from the part toward the end.

  Next, a method of replacing a used probe with an unused probe when all the probes stored in the probe storage unit 35 on the probe holder 34 are used will be described. Replacement of the used probe is performed after the probe holder 34 is moved to the spare exchange chamber 23 and the inside of the spare exchange chamber 23 is opened to the atmosphere. The exchange procedure is as follows. First, the preliminary exchange chamber 23 is evacuated, the vacuum gate valve 24 is opened, the tip of the exchange shaft 26 is moved into the sample chamber, and the probe holder 34 is connected. When the exchange shaft 26 is moved to the spare exchange chamber 23 side, the probe holder 34 moves to the spare exchange chamber 23 as shown in the plan view of FIG. If the vacuum gate 24 is closed again and the preliminary exchange chamber 23 is opened to the atmosphere, the probe can be exchanged.

  In the above-described embodiment, the sample is placed on the probe holder 34. However, the probe storage portion and the sample are not necessarily on the same holder. For example, the probe holder 34 includes only the probe storage portion. The probe may be replaced by replacing the sample holder only when the probe is replaced. Further, for example, the sample and the probe storage unit may be placed in the sample chamber at the same time and separately moved to the spare replacement chamber 23. However, in order to further shorten the time required for probe replacement, it is desirable that the probe storage unit and the sample are on the same holder.

  In the above-described embodiment, the probe holder 34 is configured to be movable to the spare exchange chamber 23 used for sample exchange. However, the probe holder 34 is not necessarily used as the spare exchange chamber for sample exchange. A spare exchange chamber for exchange and probe exchange may be provided separately. However, if the configuration is also used as a spare exchange chamber for exchanging samples, there is an advantage that the space for providing the spare exchange chamber in the sample chamber and the manufacturing cost can be saved.

  As described above, according to the present invention, the spare exchange chamber 23 only needs to be large enough to accommodate the probe holder 34, so that it can be made much smaller than the spare exchange chamber 3 of the prior art. . Therefore, the manufacturing cost can be reduced, the evacuation time can be shortened, and the operability can be improved. In addition, since a large number of unused probes can be prepared on the probe holder 34 at a time, the vacuum in the sample chamber 31 is maintained even when the probe needs to be replaced during the measurement. Since probe replacement can be performed quickly, the measurement efficiency can be greatly improved.

The longitudinal cross-sectional view which shows schematic structure of the sample chamber of the scanning electron microscope in a prior art, and its periphery. The top view which shows schematic structure of the sample chamber of the scanning electron microscope in a prior art, and its periphery. The top view which shows the state which moved the manipulator to the reserve replacement | exchange chamber in a prior art. Sectional drawing which shows schematic structure of the sample chamber of the scanning electron microscope in this invention, and its periphery. The top view which shows schematic structure of the sample chamber of the scanning electron microscope in this invention, and its periphery. The top view which shows the state which moved the sample holder to the preliminary exchange chamber in this invention. The figure for demonstrating the outline of the procedure which performs probe replacement | exchange in this invention. The perspective view which shows the probe of the state accommodated in the probe hold | maintained in the measurable state in this invention, and a probe accommodating part. The figure for demonstrating the detail of the method of exchanging a probe in a vacuum in this invention.

Explanation of symbols

(Those that perform the same or similar operations are denoted by a common reference.)
EB electron beam (charged particle beam)
DESCRIPTION OF SYMBOLS 1, 31 Sample chamber 2 Objective lens 3, 23 Preliminary exchange chamber 4, 24 Vacuum gate valve 5 Z-axis movement / tilting stage 6 Y-axis movement stage 7 X-axis movement stage 8 Manipulator base 9 X-axis movement mechanism 10 Y-axis Moving mechanism 11 Z-axis moving mechanism 12, 32 Probe mount 13 Probe mounting member 14 Sample holder 15 Sample 16, 26 Replacement shaft 18, 38 Manipulator 20 Probe replacement position 25 Rotating mechanism 27, 27a Probe 28 Probe tip 29 Probe fixing plate Spring 30 Probe storage leaf spring
33 Leaf spring support member 34 Probe holder 34a Probe tip storage hole 35 Probe storage section

Claims (6)

A charged particle having a moving mechanism capable of moving the sample holder between the sample chamber and a preliminary exchange chamber communicating with the sample chamber, and a manipulator for holding and moving the probe contacting the sample on the sample holder. In the beam device,
A probe holder provided on the manipulator for removably supporting the probe; a probe holder having a first probe storage section for storing a used probe; and a second probe storage section for storing an unused probe;
The probe support means, the first probe storage portion, and the second probe storage portion are composed of a pair of leaf springs facing each other, and an interval between the pair of leaf spring tips facing each other across the probe is It is configured to be wider than the distance between the pair of leaf spring tips facing each other that do not sandwich the probe,
In a state where the vacuum in the sample chamber is maintained, the probe support means is associated / separated with respect to the first or second probe storage portion, thereby removing the used probe from the probe support means. A charged particle beam apparatus, wherein the charged particle beam apparatus is stored in one probe storage section, and the unused probe is taken out from the second probe storage section and attached to the probe support means. 2. The charged particle beam apparatus according to claim 1, wherein the probe holder is movable between the preliminary exchange chamber communicated with the sample chamber by the moving mechanism. 3. The charged particle beam apparatus according to claim 1, wherein the sample can be placed on the probe holder. 4. The charged particle beam apparatus according to claim 1, wherein the first probe storage portion and the second probe storage portion are arranged in the vicinity of an outer periphery on the probe holder. 5. The means for moving the first probe storage portion and the second probe storage portion to a position for removing and mounting the used probe and the unused probe between the probe support means, The charged particle beam apparatus according to claim 1, wherein the charged particle beam apparatus is a means for rotating the sample holder with the center as a rotation center. 6. The charging according to claim 1, wherein the probe is formed so as to become thinner from an end portion of the body portion toward an end portion where the tip portion of the probe is supported and an opposite end portion thereof. Particle beam device.

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