JP6280495B2 - Sample fixing device - Google Patents

Description

  The present invention relates to a sample fixing device for fixing a minute sample.

The sample fixing device is used for fixing a sample when analyzing a micro sample such as a semiconductor material or a bio nano material with an electron microscope or the like. The micro sample is fixed to the sample fixing electrode portion of the sample fixing device and attached to the analyzer.
Analyzing apparatuses that analyze changes in characteristics and operations of a micro sample while a voltage is applied to the micro sample are being studied. As an example of a sample fixing device attached to such an analyzer, a mesh provided with a first wiring structure electrically connected to a micro sample and a second wiring structure connected to the first wiring structure are provided. And a sample holder for holding a mesh. The micro sample is thinned in advance to a thickness capable of transmitting an electron beam, and fixed to the mesh using a sample pressing jig and a pressing spring (see, for example, FIG. 2B of Patent Document 1).

JP 2007-303946 A

  In the sample fixing device described in Patent Document 1, it takes time to fix the sample to the mesh.

Sample fixing apparatus of this invention is formed by the semiconductor substrate, the base portion, and the micro sample stage having a sample mounting portion in which a pair of sample fixing piece is formed, an insulating film provided on one surface of the micro sample stage, And at least a pair of conductor structure portions formed on a micro sample stage via an insulating film, each of the pair of sample fixing pieces has an inner side surface and an upper surface facing each other, and each conductor structure portion is a pair of conductor structure portions . The sample fixing electrode portion is formed on the inner side surface and the upper surface of one of the sample fixing pieces , and the sample is voltage between the inner side surfaces of the pair of sample fixing pieces via the pair of sample fixing electrode portions. Is held to be impressable.

  According to the sample fixing device of the present invention, it is possible to efficiently attach the sample to the sample fixing device.

The top view which shows Embodiment 1 of the sample fixing device of this invention. The II-II sectional view taken on the line of the sample fixing device illustrated in FIG. The top view which shows the micro sample stand before forming a conductor structure part in the sample fixing device illustrated in FIG. FIG. 2 is an enlarged perspective view of a sample fixing electrode portion of the sample fixing device illustrated in FIG. 1. FIG. 5 is a perspective view illustrating a state in which a sample is held on the sample fixed electrode portion illustrated in FIG. 4. The top view for demonstrating the method to measure the electrical resistance of a sample. The equivalent circuit for demonstrating the method to measure the electrical resistance of a micro sample by the 4-terminal measuring method. The top view which shows Embodiment 2 of the sample fixing device of this invention. The top view which shows Embodiment 3 of the sample fixing device of this invention. XX sectional drawing in FIG.

Embodiment 1
Hereinafter, Embodiment 1 of the sample fixing device of the present invention will be described with reference to the drawings.
1 is a plan view showing Embodiment 1 of the sample fixing device of the present invention, FIG. 2 is a cross-sectional view taken along the line II-II of the sample fixing device shown in FIG. 1, and FIG. It is a top view which shows the micro sample stand before forming a conductor structure part in the sample fixing device shown in figure. 4 is an enlarged perspective view of the sample fixing electrode portion of the sample fixing device shown in FIG. 1, and FIG. 5 is a perspective view showing a state in which the sample is held on the sample fixing electrode portion shown in FIG. It is.
The sample fixing device 100 includes a micro sample table 10 formed of a semiconductor material such as silicon, an insulating film 20 (FIG. 2) formed on the surface of the micro sample table 10, and a pair of electrodes formed on the insulating film 20. The conductor structure part 30 is comprised.

The micro sample table 10 is a flat plate member formed by processing a semiconductor substrate by etching or the like. As shown in FIG. 3, the radius R is approximately several mm (1 to 2 mm) or less. A base part 11 having an arcuate outer peripheral part and a sample mounting part 12 formed integrally with the base part 11 are provided on the upper side of the base part 11.
In the following description, the left-right direction and the up-down direction will be described as directions shown in the drawings.
Guard parts 13 protruding above the sample mounting part 12 are formed on the left and right sides of the sample mounting part 12 of the micro sample table 10. The guard part 13 is formed integrally with the base part 11 and the sample mounting part 12. The guard unit 13 prevents the analysis device or the like from colliding with the micro sample 71 in the operation of fixing the micro sample 71 (see FIG. 5) to the micro sample stage 10 or analyzing the fixed micro sample 71. Is to do. Further, when the sample fixing device 100 falls, the micro sample 71 is guarded.
The micro sample stage 10 has a line-symmetric shape with respect to the center line CL, and the left and right guard portions 13 are formed in the same shape.

  The sample mounting portion 12 includes a leg portion 17 having a tapered substantially trapezoidal shape and a sample fixing body 18 formed on the leg portion 17. As shown in FIG. 4, the sample fixing body 18 is formed with a pair of sample fixing pieces 18 a at the top. The sample fixing piece 18 a has an inner side surface 51 on the surface side facing each other, an outer side surface 52 on the opposite side of the inner side surface 51, and an upper surface 53. The sample fixing piece 18a is formed in a tapered shape with the inner side surface 51 inclined in a direction in which the interval increases toward the tip side. The sample fixing body 18 having the leg portion 17 and the pair of sample fixing pieces 18a is formed integrally with the base body 11 by one semiconductor substrate.

  As shown in FIG. 2, the surface of the micro sample table 10 is covered with an insulating film 20 formed of an oxide film or the like. Since the micro sample table 10 is formed of a semiconductor substrate such as silicon, a natural oxide film is formed on the entire surface of the micro sample table 10 during and after the processing of the micro sample table 10. The insulating film 20 is composed of a natural oxide film formed on the surface of the micro sample table 10 in this way. An insulating film 20 may be formed by forming an inorganic silicide film such as a silicon oxide film or a silicon nitride film on the natural oxide film.

A pair of conductor structures 30 made of gold or copper is formed on the insulating film 20 formed so as to cover one surface 10a of the micro sample table 10.
As shown in FIG. 1, each conductor structure portion 30 is formed on an external voltage pad (external voltage application pad) 31, a measurement pad 32, and a sample attachment portion 12 formed on the base portion 11. It has the sample fixed electrode part 33 extended. The external voltage pad 31, the measurement pad 32, and the sample fixing electrode portion 33 are electrically connected by a routing portion 34.

  For example, the conductor structure unit 30 forms a base metal film on the entire surface of the insulating film 20 covering one surface 10a of the micro sample table 10 by sputtering, vapor deposition, or the like, and forms an electroplated film on the base metal film. The pattern can be formed by etching using a mask, so-called photoetching.

  As shown in FIG. 4, the sample fixing electrode portion 33 of the conductor structure portion 30 includes a surface electrode portion 33 d formed on the surface of the sample fixing piece 18 a of the sample fixing body 18, and an inner side surface 51 of the sample fixing piece 18 a. It has an inner surface 33a formed on the upper surface, an outer surface 33b formed on the outer side surface 52, and an upper end surface 33c formed on the upper surface 53, and is formed with the insulating film 20 interposed therebetween. One conductor structure 30 and the other conductor structure 30 are formed so as not to be short-circuited.

As shown in FIG. 5, the micro sample 71 is attached by being sandwiched between the sample fixing pieces 18 a of the micro sample table 10. In this state, it closely adheres to the inner side surface 33a of the sample fixing electrode portion 33 of the conductor structure portion 30 provided on each sample fixing piece 18a. Therefore, a voltage can be applied to the micro sample 71 from the outside via the conductor structure 30. Then, in a state where a voltage is applied from the outside, for example, a semiconductor material or a micro sample 71 formed by implanting ions or the like into the semiconductor material is observed with a detection device such as an electron microscope, and a non-application state and an application state are observed. It is possible to contrast changes in characteristics and changes in operation. Alternatively, it is possible to irradiate a micro sample with an ion beam, detect secondary ions emitted from the micro sample with a secondary ion detector (not shown), and analyze the physical properties thereof. It is also possible to use a biomaterial as a minute sample.
It is also possible to accurately measure the electrical resistance of the micro sample 71 using a four-terminal measurement method. This will be described below.

FIG. 6 is a plan view for explaining a method of measuring the electrical resistance of the sample. FIG. 7 is an equivalent circuit for explaining a method of measuring the electrical resistance of a minute sample by a four-terminal measurement method.
As shown in FIG. 6, the microprobe 73 is brought into contact with the external voltage pad 31 and the measurement pad 32 of each conductor structure 30.
As shown in FIG. 7, a voltage is applied by a power source 74 through a microprobe 73. A current flowing from the power supply 74 to the external voltage pad 31 is measured by an ammeter 75. Further, the voltage between the measurement pads 32 is measured by the voltmeter 76 through the microprobe 73.

（但し、ｉ＝ｉ_s+ｉ_v）
上記式により、微小試料７１の電気抵抗Ｒ_Sを求めることができる。 The electric resistance of the micro-sample 71 R _S, the internal impedance of the voltmeter 76 and R _v, r _i, the R _i, respectively, the contact resistance, when the electrical resistance of the conductor of the conductor structure 30, Kirchhoff's law of currents The following equation is obtained from

(However, i = i _s + i _v )
The electrical resistance R _S of the micro sample 71 can be obtained from the above formula.

According to the said Embodiment 1, there exist the following effects.
(1) A pair of sample fixing pieces 18a is provided on the micro sample table 10, and the fine sample 71 is fixed between the sample fixing pieces 18a. For this reason, the micro sample 71 can be fixed easily and efficiently.

(2) The micro sample table 10 is formed of a semiconductor substrate. Since the semiconductor substrate can be efficiently processed with high accuracy by etching or the like, the sample fixing device 100 can be manufactured with high accuracy and the production efficiency can be increased.

(3) The insulating film 20 that insulates the micro sample table 10 from the conductor structure 30 is formed using an oxide film formed on the micro sample table 10 during and after the processing of the micro sample table 10. For this reason, the formation of the insulating film 20 becomes efficient, and the productivity of the sample fixing device 100 can also be improved by this.

(4) The sample fixing device 100 is provided with the conductor structure portion 30 having the sample fixing electrode portion 33 and the external voltage pad 31. A voltage can be applied to the micro sample 71 from the outside simply by directly contacting the external voltage pad 31 with the micro probe 73 connected to an external power source. In this state, it is possible to analyze the characteristics of the micro sample 71 and changes in operation. For this reason, it is possible to shorten the time until the analysis is started after the micro sample 71 is fixed to the sample fixing device 100.

(5) The sample fixing device 100 shown in the first embodiment can be formed only by adding the conductor structure 30 to a conventional sample fixing device that does not have the conductor structure 30. That is, the micro sample stage 10 of the present invention can be manufactured by using a conventional sample fixing device that performs analysis without applying a voltage to the micro sample 71 as it is.
Therefore, an analysis performed by applying a voltage to the micro sample 71 from the outside using the sample fixing device 100 of the present embodiment and an analysis performed without applying a voltage to the micro sample 71 using a conventional sample fixing device. Can be performed using the same analyzer. That is, since it can be used as it is without improving the analyzer, it is advantageous in terms of capital investment. In addition, the micro sample 71 to be manufactured can be shared, and the efficiency of manufacturing the micro sample can be improved. Furthermore, it is possible to refer to analysis data of a conventional minute sample.

(6) The conductor structure portion 30 has a structure having a sample fixing electrode portion 33, an external voltage pad 31 and a measurement pad 32 connected to the sample fixing electrode portion 33. For this reason, the electrical characteristics of the micro sample 71 can be accurately measured using the four-terminal measurement method.

Embodiment 2
FIG. 8 is a plan view showing Embodiment 2 of the sample fixing device of the present invention.
The micro sample stage 10A of the sample fixing device 100A shown in the second embodiment includes three sample mounting portions 12.
Similar to the sample fixing device 100 of the first embodiment, a sample fixing body 18 having a pair of sample fixing pieces 18a is formed on each sample mounting portion 12 of the micro sample table 10A.
Each sample fixing piece 18 a has a conductor structure 30 or 30 </ b> A extending from the base body 11.

  At both ends in the left-right direction of the micro sample mounting base 10A, a conductor structure portion 30 similar to the sample fixing device 100 of the first embodiment is provided. That is, the conductor structure portion 30 includes an external voltage pad 31, a measurement pad 32, a sample fixing electrode portion 33, and a routing portion 34.

A conductor structure portion 30A is formed between the sample mounting portion 12 at the center of the small sample mounting base 10A and the sample mounting portion 12 adjacent to the sample mounting portion 12 at the center. The conductor structure portion 30 </ b> A has a structure in which the sample fixing electrode portions 33 formed adjacent to each other among the pair of sample fixing electrode portions 33 provided in each sample mounting portion 12 are connected by the connection portion 36. Each conductor structure portion 30 </ b> A has one measurement pad 32 for the sample fixed electrode portion 33. Each conductor structure portion 30 </ b> A does not have the external voltage pad 31.
Other configurations in the second embodiment are the same as those in the first embodiment.

  In the sample fixing device 100A of the second embodiment, the three sample mounting portions 12 are provided with a sample fixing body 18 having a pair of sample fixing pieces 18a constituting the conductor structure portions 30 and 30A, respectively. The sample fixing body 18 holds and holds the micro sample 71 between the pair of sample fixing pieces 18a, and the micro sample 71 can be analyzed in this state. Further, the electrical resistance of the micro sample 71 can be measured by the four-terminal measurement method with the micro sample 71 sandwiched between the pair of sample fixing pieces 18a.

Therefore, the second embodiment also has the same effect as the first embodiment.
In the second embodiment, since a plurality of micro samples 71 can be simultaneously fixed to each sample fixing body 18, the micro samples 71 can be continuously analyzed, and the efficiency of analysis work can be increased. it can.

Embodiment 3
FIG. 9 is a plan view showing Embodiment 3 of the sample fixing device of the present invention, and FIG. 10 is a sectional view taken along line XX in FIG.
The sample fixing device 100B of Embodiment 3 includes a conductor structure portion 30B. The conductor structure section 30B includes a sample fixing electrode section 33, an external voltage pad 31, and a connection section 37 that connects the sample fixing electrode section 33 and the external voltage pad 31.
As shown in FIG. 10, an opening 21 that exposes the surface 10 a of the micro sample table 10 is provided in a portion of the insulating film 20 facing the external voltage pad 31 of the conductor structure 30 </ b> B. The conductor structure 30 </ b> B provided so as to cover the opening 21 is joined to the surface 10 a of the micro sample table 10 exposed from the opening 21. That is, a diode having a potential barrier such as a Schottky diode is formed by joining a metal external voltage pad 32 and silicon or the like.
As described above, the micro sample 71 is sandwiched between the pair of sample fixing pieces 18 a and is held in an electrically conductive state with each sample fixing body 18.

In this state, the microprobe is brought into contact with the external voltage pad 31 of each conductor structure 30B to apply an external voltage. As a result, a current i flows between the external voltage pads 31 of the micro sample stage 10 as shown in FIG.
Here, the sample fixing device 100B is heated by irradiating thermal energy from a light source (not shown), and the micro sample 71 fixed to the sample fixing device 100B is heated.
As described above, a diode having a potential barrier at the junction surface with the conductor structure portion 30B is formed on the micro sample table 10 formed of a semiconductor material such as silicon. Since this type of diode has a correlation between temperature and allowable current, the temperature of the microsample table 10 and thus the temperature of the microsample 71 are detected by detecting the current flowing between the external voltage pads 32. be able to.
Therefore, by analyzing the micro sample 71, it is possible to analyze the physical properties of the micro sample 71 and the temperature characteristics of the operation.
Other configurations in the third embodiment are the same as those in the first embodiment.

Also in the third embodiment, the effects (1) to (5) described in the first embodiment can be achieved.
Furthermore, in the third embodiment, the sample fixing device 100B itself can have the function of a temperature sensor, and the physical properties of the micro sample 71 and the temperature characteristics of the operation can be analyzed inexpensively and efficiently. There is an effect.

  In each of the above embodiments, each of the pair of sample fixing pieces 18a is formed in a tapered shape that is inclined in a direction in which the distance between the sample fixing pieces 18a increases toward the distal end side. However, the sample fixing piece 18a may be a vertical surface or may be provided with fine irregularities or steps on the inner side surface.

  In each of the above embodiments, the conductive structures 30, 30 </ b> A, 30 </ b> B (hereinafter, representatively “30”) are formed on the micro sample table 10 by sputtering or plating via the insulating film 20. As an example. However, the conductor structure 30 may be formed of a conductive metal foil such as gold or copper and adhered to the micro sample table 10. In the case of this structure, the micro sample stage 10 has a structure in which the pair of sample fixing pieces 18 a are not formed on the sample mounting portion 12. That is, only the pair of sample fixing electrode portions 33 of the conductor structure portion 30 protrudes above the sample mounting portion 12. The micro sample 71 is sandwiched and held between a pair of sample fixing electrode portions 33 formed of a conductive metal foil. In this structure, since the flexibility of the sample fixing electrode portion 33 can be increased, the micro sample 71 can be easily fixed.

  In each said embodiment, the micro sample stand 10 was illustrated as a member in which the whole was formed with the semiconductor substrate. However, the base portion 11 and the sample mounting portion 12 are formed of a semiconductor substrate, an inorganic silicon film such as a silicon oxide film or a silicon nitride film is formed on the surface of only the sample mounting portion 12, the base material is removed, and the sample mounting portion 12 You may form with an inorganic silicon film. A micro sample stage having such a structure is disclosed in Japanese Patent Application Laid-Open No. 2010-271101. Further, the micro sample table 10 may be formed of a member other than a semiconductor.

  In addition, the present invention can be applied in various modifications. In short, a pair of conductor structure portions are provided on one surface of a micro sample table having a sample attachment portion, and each conductor structure portion is provided with a sample attachment portion. What is necessary is just to have the sample fixed electrode part formed protruding from the part and to be able to hold the sample between the pair of sample fixed electrode parts.

DESCRIPTION OF SYMBOLS 10 Minute sample stand 10a Surface 11 Base part 12 Sample mounting part 13 Guard part 17 Leg part 18 Sample fixing body 18a Sample fixing piece 20 Insulating film 21 Opening part 30, 30A, 30B Conductor structure part 31 External voltage pad (external voltage application) Pad)
32 Measurement pad 33 Sample fixing electrode portion 33a Inner side surface 33b Outer side surface 33c Upper end surface 34 Leading portion 36 Leading portion 71 Micro sample 73 Micro probe 100, 100A, 100B Sample fixing device

Claims (5)

Formed by the semiconductor substrate, and the minute sample table having a base portion, and the sample mount portion in which a pair of sample fixing piece is formed,
An insulating film provided on one surface of the micro sample table ;
Comprising at least a pair of conductor structures formed on the micro sample table via the insulating film;
Each of the pair of sample fixing pieces has an inner side surface and an upper surface facing each other,
Each conductor structure portion has a sample fixing electrode portion formed on the inner side surface and the upper surface of one of the pair of sample fixing pieces ,
A sample fixing device in which a sample is held between the inner side surfaces of a pair of the sample fixing pieces so that a voltage can be applied via the pair of sample fixing electrode portions . The sample fixing device according to claim 1,
The micro sample stage is a sample fixing device formed of a silicon substrate . In the sample fixing device according to claim 1 or 2 ,
Each said conductor structure part is provided in the said base | substrate part of the said micro sample stand, The sample fixing device provided with the pad for an external voltage application which an external terminal member contacts. The sample fixing device according to claim 3 , wherein
The sample fixing device, wherein the external voltage application pad includes an external voltage pad and a measurement pad connected to the sample fixing electrode section. The sample fixing device according to claim 4, wherein
The sample fixing device, wherein the external voltage pad of the conductor structure part is bonded to the surface of the base part through an opening provided in the insulating film.

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