JP2015046338A - Cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning device capable of uniform cleaning of a sample observed by a scanning electron microscope.SOLUTION: A sample observation 14a is exposed uniformly to a plasma space 16 generated above an electrode 4, by arranging rods 25 on the first bottom wall 2b of a processing chamber 1 near the electrode 4 at a predetermined interval, and then fitting the dovetail groove 22f of a dovetail groove holder 22 and the rod 25. Furthermore, since the sample observation 14a is arranged near the electrode 4 in the plasma space 16 where the density of ions, ozone, radicals, and the like, is high, it is strongly affected by chemical reaction with ions, ozone, radicals, and the like, and thereby is cleaned efficiently.

Description

  The present invention relates to an apparatus for cleaning a sample such as an electron microscope.

  When observing a sample with an electron microscope such as a transmission electron microscope or a scanning electron microscope, dirt (carbon, metal, oil, fat, moisture, oxide, etc.) adheres to the sample surface, which hinders the observation and analysis of the sample. It is well known.

  In order to avoid such problems, the sample surface is generally cleaned prior to observation.

  The cleaning device arranges a sample in a plasma space generated by glow discharge, and removes dirt adhering to the sample surface by a chemical reaction with ions, ozone, radicals, and the like. In addition, there is an apparatus that can clean the sample holder together with the sample by putting the sample holder together with the sample while holding the sample (see, for example, Patent Document 1).

  FIG. 1 shows a conventional cleaning device. 1A is a front view, and FIG. 1B is a cross-sectional view of FIG. 1A viewed from the dotted line AA ′ in the direction of the arrow.

  A processing chamber 1 in a conventional cleaning apparatus includes a processing chamber side wall 2a that is a side surface of the processing chamber, and a processing chamber first bottom wall 2b and a processing chamber second bottom wall 2c that are bottom surfaces of the processing chamber. It is a space surrounded by the wall 2. The processing chamber second bottom wall 2 c supports the electrode 4 through the insulator 3. The electrode 4 is disposed at the same level with a slight gap 5 from the first bottom wall 2b of the processing chamber. Furthermore, the processing chamber 1 becomes a sealed space by placing a lid 6 made of a visible material such as glass on the processing chamber side wall 2a. The lid 6 can be removed, and an O-ring 7 is provided at a contact portion with the processing chamber side wall 2a. An exhaust unit (vacuum pump) 10 for exhausting the processing chamber and a gas supply unit (gas cylinder) 12 whose flow rate can be adjusted by a flow rate adjusting valve 11 are connected to the processing chamber 1.

  The processing chamber side wall 2a is provided with an insertion hole for inserting a TEM sample holder 9 holding a transmission electron microscope (TEM) sample 8 at the tip. The TEM sample holder 9 also serves as the processing chamber wall 2 as a part of the processing chamber side wall 2a. When cleaning the TEM sample 8, the TEM sample holder 9 is inserted into the insertion hole so that the TEM sample 8 is positioned above the electrode 4.

  Further, the conventional cleaning apparatus is provided with an AC power source 13 for applying an AC voltage between the electrode 4 and the processing chamber wall 2. The processing chamber wall side of the AC power supply 13 is connected to the ground.

  In the apparatus having such a configuration, the SEM sample holder 15 holding the sample 14 of the scanning electron microscope (SEM) having the sample observation surface 14a on the sample support surface 15a may be put into the processing chamber 1 for cleaning. When cleaning the SEM sample 14, a dummy TEM sample holder of the same type as the TEM sample holder 9 is inserted into the insertion hole of the processing chamber side wall 2a to close the insertion hole.

  When the operator sets the processing time using a timer and then instructs the start of cleaning, the cleaning device first evacuates the processing chamber 1 with the vacuum pump 10, and then continues the evacuation and continues the evacuation. Thus, gas is introduced from the gas cylinder 12 into the processing chamber 1 to balance the exhaust and gas supply, and the processing chamber 1 is maintained at a pressure of about 35 to 40 Pa. At this time, since the pressure in the processing chamber 1 is lower than the outside (atmospheric pressure) of the processing chamber 1, the lid 6 is pressed inside the processing chamber 1. For this reason, the lid 6 during sample cleaning cannot be removed from the processing chamber wall 2.

  Next, the cleaning device operates the AC power supply 13 and applies a voltage of about 300 V to the electrode 4 to generate glow discharge. Then, a plasma space 16 is generated on the electrode 4, and dirt adhering to the sample observation surface 14 a of the sample 14 in the plasma space 16 and the surface of the SEM sample holder 15 chemistry with ions, ozone, radicals, etc. in the plasma space 16. It is cleaned by reaction.

JP 2002-162324 A

  When the sample of the scanning electron microscope is cleaned with such a cleaning device, the manner in which the sample observation surface 14a exposed to the plasma space 16 is exposed is not constant depending on the position and orientation of the sample holder for observation of the scanning electron microscope. .

  Further, in the case of the cleaning device configured as shown in FIG. 1, since the area of the electrode 4 is smaller than the area of the processing chamber wall 2, the potential difference between the plasma and the electrode 4 is between the plasma and the processing chamber wall 2. The region of the plasma space 16 is biased to a location close to the electrode 4, and the density of ions, ozone, radicals, and the like increases in the vicinity of the electrode 4.

  Therefore, in the processing of the sample observation surface 14a, the cleaning effect varies depending on the position and orientation of the SEM sample holder 15, and it is difficult to uniformly clean the sample observation surface 14a.

  Further, in an apparatus capable of cleaning both the TEM sample holder 9 and the SEM sample holder 15, the TEM sample holder 9 or the dummy TEM sample holder is always positioned above the electrode 4. For this reason, in order to keep the sample observation surface 14a parallel to the electrode 4, holding the SEM sample holder 15 on the upper side of the processing chamber or on the lid side is a positional relationship with the TEM sample holder 9 or the dummy TEM sample holder. More difficult.

  The present invention has been made in view of these points, and an object of the present invention is to provide a cleaning apparatus that can uniformly clean the surface of a sample used for observation with a scanning electron microscope.

  The cleaning device of the present invention that achieves the above object supplies gas from a gas supply means to a chamber connected to an exhaust means, and is provided between the chamber and an electrode insulated from the chamber located on the bottom surface of the chamber. A cleaning is performed by applying a voltage to the chamber and the electrode by a power source to generate a discharge, generating a plasma space in the chamber, and cleaning a sample holder holding the sample and the sample on the sample support surface in the plasma space. In the apparatus, the sample holder includes an engaging portion that engages with the chamber, and the chamber is configured so that the sample support surface of the sample holder holds the sample holder upright toward the center of the electrode. A locking portion for locking the engaging portion of the sample holder is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the cleaning apparatus which can clean the sample surface of the sample for scanning electron microscopes uniformly can be provided.

It is shown in order to demonstrate the conventional cleaning apparatus. An example of the state which mounted | wore the scanning electron microscope apparatus with the sample holder is shown. An example of the sample holder of the state holding the sample is shown. An example of the cleaning device of the present invention is shown. An example of the cleaning apparatus which set the sample holder of this invention is shown. The other example of the state which mounted | wore the scanning electron microscope apparatus with the sample holder is shown. The other example of the sample holder of the state holding the sample is shown. It shows another example of the cleaning device of the present invention. The other example of the cleaning apparatus which set the sample holder is shown.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the same or similar components as those of the conventional cleaning device shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 2 shows an example of a state in which the sample holder is mounted on the scanning electron microscope apparatus.

  The sample chamber 21 formed by the sample chamber wall 17 includes an electron beam irradiation means 18 for irradiating the electron beam 19, a vacuum pump 20 for exhausting the sample chamber 21, and a sample stage 23 engaged with the dovetail groove. It has.

  FIG. 3 shows a dovetail sample holder in a state where the sample 14 is held. 3A is a front view, FIG. 3B is a side view, and FIG. 3C is a top view.

  As shown in FIG. 3A, the dovetail sample holder 22 has a structure having a sample support surface 22a on the upper surface of the holder body and an dovetail groove (engaging portion) 22f on the lower portion of the holder body. The dovetail groove 22f is constituted by a space surrounded by a parallel surface 22e parallel to the holder lower surface 22d of the dovetail groove sample holder 22, and an acute tapered surface 22b and a tapered surface 22c with respect to the holder lower surface 22d.

  The dovetail sample holder 22 holds the sample 14 on the sample support surface 22 so that the sample observation surface 14a to be observed with the scanning electron microscope device faces upward. Furthermore, the holder lower surface 22d is parallel to the sample support surface 22a.

  Here, an operation example when the dovetail sample holder 22 to be cleaned by the cleaning device of the present invention is used in the scanning electron microscope device will be described. As shown in FIGS. 2 and 3, the dovetail groove 22f of the dovetail sample holder 22 is fitted and held in the tenon (locking portion) of the sample stage 23 of the scanning electron microscope apparatus. In this state, the sample chamber 21 is evacuated by the vacuum pump 20. Next, the sample observation surface 14a is irradiated with an electron beam 19, and secondary electrons generated by the electrons irradiated on the sample observation surface 14a are detected by a secondary electron detector (not shown). When irradiating the sample observation surface 14a with the electron beam 19, a secondary electron image is obtained by two-dimensional scanning.

  FIG. 4 shows the cleaning device of the present invention. 4A is a front view, and FIG. 4B is a cross-sectional view as seen from the dotted line BB ′ in FIG. 4A in the direction of the arrow.

  The cleaning device of the present invention is further provided with a rod (locking portion) 25 for holding the sample holder by fitting into the dovetail groove 22f of the dovetail sample holder 22 with respect to the cleaning device shown in the conventional example, A groove portion 26 is provided for fitting with the groove sample holder 22 main body. A dummy TEM sample holder 24 used for cleaning the SEM sample 14 is also provided. The dummy TEM sample holder 24 seals the insertion hole provided in the processing chamber side wall 2 a in place of the TEM sample holder 9 and plays a part of the processing chamber wall 2.

  The rod 25 is a columnar rod provided near the electrode 4 and is erected at two positions at a predetermined interval on a groove 26 provided in the processing chamber first bottom wall 2b.

  The predetermined interval between the rods 25 erected at two positions is such that the rod 25a is in contact with the parallel surface 22e and the tapered surface 22b constituting the dovetail groove 22f of the dovetail sample holder 22, and the rod 25b is in contact with the parallel surface 22e and the tapered surface 22c. Will be in contact.

  Next, a procedure for setting the sample holder in the cleaning device will be described.

  First, the lid 6 is removed from the cleaning device, and the dovetail groove 22f of the dovetail specimen holder 22 is fitted to the rod 25 and attached. At this time, the sample support surface 22 a is fitted so as to face the electrode 4. Here, the main body of the dovetail sample holder 22 is fitted into the groove 26 at the same time as the rod 25, whereby further stability can be maintained. Then, the lid 6 is placed on the processing chamber wall 2 provided with the O-ring 7 to finish the setting of the sample holder 22.

  FIG. 5 shows the cleaning device with the sample holder set. FIG. 5A is a front view, and FIG. 5B is a cross-sectional view as viewed from the dotted line CC ′ in FIG.

  As shown in FIG. 5, since the dovetail groove 22f is fitted to the rod 25 standing on the groove 26 of the processing chamber first bottom wall 2b, the sample support surface 22a of the dovetail sample holder 22 is formed in the processing chamber. 1 is held in a state where it stands in a vertical direction with respect to the electrode 4 disposed on the bottom surface of 1.

  Here, the cleaning procedure of the cleaning device of the present invention will be described.

  First, the dovetail sample holder 22 is set in accordance with the procedure for setting the cleaning device described above.

  Next, after the processing chamber 1 is evacuated by the vacuum pump 10 of the cleaning device, the gas is introduced from the gas cylinder 12 by the flow rate adjusting valve 11 to keep the pressure in the processing chamber 1 at about 35 to 40 Pa. At this time, the gas cylinder 12 is not always necessary, and air may be introduced as a gas.

  Thereafter, an AC voltage of about 300 V is applied between the electrode 4 and the processing chamber wall 2 by the AC power source 13 to generate a glow discharge on the electrode 4 to form a plasma space 16 on the electrode 4. Here, since the sample observation surface 14a is disposed in the vicinity of the electrode 4 where the density of ions, ozone, radicals, etc. in the generated plasma space 16 is high, it is strongly influenced by chemical reaction with ions, ozone, radicals, etc. It is cleaned efficiently.

  The sample observation surface 14 a is held in a state where it faces the direction of the electrode 4 and stands in a direction perpendicular to the electrode 4. For this reason, the distance from the sample observation surface 14a to the electrode 4 is substantially constant with respect to the entire surface of the sample observation surface 14a, and the entire surface of the sample observation surface 14a is substantially free from etching effects such as ions, ozone, radicals, and chemical reactions. Evenly received and cleaned.

  In the above, the sample holder which has a dovetail was demonstrated about one Example of this invention.

  Other embodiments will be described below. However, the same or similar components as those described in FIGS. 1 to 5 are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 6 shows an example of a state in which a sample holder used in another embodiment is mounted on a scanning electron microscope apparatus.

  The scanning electron microscope apparatus of another embodiment includes a sample stage 28 provided with a lateral groove sample holder 27 having a groove on the side surface of the holder and a pressing portion for locking the groove of the horizontal groove sample holder 27.

  FIG. 7 shows a transverse groove sample holder in a state where the sample 14 is held. 7A is a front view, FIG. 7B is a side view, and FIG. 7C is a top view.

  As shown in FIG. 7 (a), the lateral groove sample holder 27 has a sample support surface 27a on the upper surface of the holder body, a groove portion (engaging portion) 27b on the holder side surface 27d side, and a groove portion (on the holder side surface 27e side). It has a structure having an engaging portion) 27c. For this reason, bulging portions 27f and 27g are formed at the upper portion of the holder body, and further, bulging portions 27h and 27i are formed at the lower portion of the holder body.

  The transverse groove sample holder 27 holds the sample 14 on the sample support surface 27a so that the sample observation surface 14a faces upward. Further, the holder lower surface 27j is parallel to the sample support surface 27a.

  FIG. 8 shows a cleaning device according to another embodiment of the present invention. FIG. 8A is a front view, and FIG. 8B is a cross-sectional view seen from the dotted line DD ′ in FIG. 8A in the direction of the arrow.

  In FIG. 8, a rod (locking portion) 29 is a rod for fitting the groove portion 27 b and the groove portion 27 c of the transverse groove sample holder 27 to hold the transverse groove sample holder 27.

  The rod 29 is a columnar rod provided in the vicinity of the electrode 4, and is erected at two positions on the processing chamber first bottom wall 2 b and the groove 26 with a predetermined interval.

  The predetermined interval between the bars 29 provided upright at two locations is about the width of the holder side surface 27d and the holder side surface 27e of the transverse groove sample holder 2. At this time, the rod 29a is surrounded by the upper bulging portion 27f, the holder side surface 27d, and the lower bulging portion 27h, and is in contact with the bulging portion 27f, the holder side surface 27d, and the bulging portion 27h. Similarly, the rod 29b is in contact with the bulging portion 27g, the holder side surface 27e, and the bulging portion 27i.

  When the rod 29a is in contact only with the bulging portion 27h and the holder side surface 27d, and the rod 29b is in contact with only the bulging portion 27i and the holder side surface 27e, one new rod that is in contact with the holder lower surface 27j is used. What is necessary is just to provide.

  Next, a procedure for setting the sample holder in the cleaning device of another embodiment will be described.

  First, the lid 6 is removed from the cleaning device, and then the groove portion of the transverse groove sample holder 27 is fitted to the rod 29 and attached. At this time, the transverse groove sample holder 27 is fitted in the direction in which the groove 27b corresponds to the rod 29a and the groove 27c corresponds to the rod 29b. Here, the main body of the transverse groove sample holder 27 can be fitted with the groove 29 at the same time as the rod 29, so that further stability can be maintained. Then, the lid 6 is placed on the processing chamber wall 2 provided with the O-ring 7 and the setting of the transverse groove sample holder 27 is completed.

  FIG. 9 shows a cleaning device in which a sample holder of another embodiment is set. FIG. 9A is a front view, and FIG. 9B is a cross-sectional view seen from the dotted line EE ′ in FIG. 9A in the direction of the arrow.

  As shown in FIG. 9, the sample support surface 27 a is engaged with the holder main body of the lateral groove type sample holder 27 sandwiched between the rods 29, and is held in a state where it stands in the vertical direction with respect to the electrode 4.

  In the cleaning apparatus according to another embodiment, even if the structure has a groove portion such as the transverse groove sample holder 27, the transverse groove sample holder 27 can be efficiently and stably held with a minimum configuration simply by adjusting the arrangement of the rods. Can do. As for the other embodiments, as in the previous embodiments, the sample observation surface 14a can be cleaned uniformly and efficiently.

  In addition, if the rod which latches the dovetail sample holder 22 and the transverse groove sample holder 27 of the present invention can be fixed so that the sample holder cannot be moved by fitting into the dovetail groove 22f or the groove portions 27b and 27c, the material can be shaped. It doesn't matter. For example, the locking portion of the cleaning device may be a plate instead of a bar. If only the dovetail groove sample holder 22 is used, the locking portion of the cleaning device may be a tenon-like protrusion that fits into the dovetail groove 22f.

  Furthermore, in addition to the sample holders shown in the examples and other examples, the sample holder can be held by changing the shape and number of the bars as the locking portions. For example, in the case of the lateral groove sample holder shown in the other embodiments, if the sample holder has a configuration in which the upper bulging portions 27f and 27g are missing, three engaging bars are used as the engaging portion. The sample holder can be held by arranging a bar at a position in contact with the bulging portion 27h (27i) and the holder side surface 27d (27e) and a position in contact with the holder lower surface 27j.

  DESCRIPTION OF SYMBOLS 1 ... Processing chamber, 2 ... Processing chamber wall, 2a ... Processing chamber side wall, 2b ... Processing chamber 1st bottom wall, 2c ... Processing chamber 2nd bottom wall, 3 ... Insulator, 4 ... Electrode, 5 ... Gap, 6 ... Lid, 7 ... O-ring, 8 ... TEM sample, 9 ... TEM holder, 10 ... Vacuum pump, 11 ... Flow control valve, 12 ... Gas cylinder, 13 ... AC power supply, 14 ... Sample, 14a ... Sample observation surface, 15 ... SEM sample holder, 15a ... sample support surface, 16 ... plasma space, 17 ... sample chamber wall, 18 ... electron beam irradiation means, 19 ... electron beam, 20 ... vacuum pump, 21 ... sample chamber, 22 ... dovetail sample holder, 22a ... Sample support surface, 22b ... Taber surface, 22c ... Taper surface, 22d ... Holder bottom surface, 22e ... Parallel surface, 22f ... Dovetail groove, 23 ... Sample stage, 24 ... Dummy TEM sample holder, 25 ... Bar, 25a ... Bar 25b ... rod, 26 ... groove, 27 Cross groove sample holder, 27a ... sample support surface, 27b ... groove, 27c ... groove, 27d ... holder side, 27e ... holder side, 27f ... bulge, 27g ... bulge, 27h ... bulge, 27i ... bulge Part, 27j ... bottom surface of holder, 28 ... sample stage, 29 ... bar, 29a ... bar, 29b ... bar

Claims (5)

Gas is supplied from a gas supply means to a chamber connected to the exhaust means, and a voltage is applied to the chamber and the electrode by a power source provided between the chamber and an electrode insulated from the chamber located on the bottom surface of the chamber. In the cleaning device for causing discharge by applying, generating a plasma space in the chamber, and cleaning a sample holder holding the sample and the sample on the sample support surface in the plasma space,
The sample holder includes an engaging portion that engages with the chamber;
The chamber includes a locking portion that locks the engaging portion of the sample holder so that the sample support surface of the sample holder stands and holds the sample holder toward the center of the electrode. A cleaning device characterized by. The sample holder has a sample support surface at the upper part and an engaging part at the lower part,
The cleaning device according to claim 1, wherein the shape of the engaging portion is a dovetail groove. The sample holder has a sample support surface at the upper part and an engaging part at the lower part,
The cleaning device according to claim 1, wherein the engaging portion is a bulging portion provided so as to protrude from a side surface of the sample holder.   The cleaning device according to claim 1, wherein the locking portion of the chamber is a plurality of bars for locking the engaging portion of the sample holder. The cleaning apparatus according to claim 1, wherein the chamber is provided with a groove for fitting and holding the sample holder on the bottom surface of the chamber.

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