JP4398396B2 - Ion milling equipment - Google Patents

Description

  The present invention relates to an ion milling apparatus, and more particularly, to an ion milling apparatus that allows easy alignment of a sample and a mask that shields a part of the sample.

  An ion milling device is a device for polishing the surface or cross section of metal, glass, ceramic, etc. by irradiating an argon beam, etc. As a pretreatment device for observing the surface or cross section of a sample with an electron microscope Is preferred.

  In the cross-sectional observation of a sample with an electron microscope, conventionally, the vicinity of the part to be observed is cut using, for example, a diamond cutter, a thread saw, etc., and then the cut surface is mechanically polished and attached to a sample stage for an electron microscope. I was observing.

  In the case of mechanical polishing, for example, a soft sample such as a polymer material or aluminum has a problem that the observation surface is crushed or deep scratches remain due to abrasive particles. In addition, for example, a hard sample such as glass or ceramic is difficult to polish, and a composite material in which a soft material and a hard material are laminated has a problem that cross-section processing is extremely difficult.

  On the other hand, ion milling has the effect that a hard sample and a composite material can be polished, and a cross section in a mirror state can be easily obtained, even if a soft sample can be processed without collapsing the surface form.

  Patent Document 1 describes a sample holder and a holder fixture of an ion milling apparatus.

JP-A-9-293475

  In the case of ion milling, it is necessary to accurately align the center of the ion beam with the portion of the sample to be mirror polished. In addition, it is necessary to expose only the part of the sample to be mirror polished and to shield the other part with a mask. In an ion milling apparatus, a sample is usually fixed to a sample holder, and the sample holder is fixed to a sample holder fixture. On the sample holder fixture installed in the vacuum chamber, it is not easy to accurately align the mask position with the processed surface of the sample due to the structural limitations of the ion milling apparatus. For this reason, as a result, it is not easy to accurately position the portion of the sample to be mirror polished and the center of the ion beam.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ion milling apparatus that can easily perform an alignment operation for aligning a mask position with a portion of a sample to be mirror polished.

  The present invention includes a sample mask unit main body in which a sample holder and its rotation mechanism, and a mask for shielding a part of the sample and a mechanism for finely adjusting the position of the mask are integrated. It is configured so that it can be attached to and detached from the sample holder fixture and can be taken out of the vacuum chamber.

  In this invention, it is also possible to comprise so that both a sample mask unit main body and a sample holder fixing tool can be taken out of a vacuum chamber, and it is contained in the embodiment of this invention.

  According to the present invention, a sample mask unit main body or a sample holder fixing tool that fixes the sample mask unit main body is pulled out of the vacuum chamber and placed under another high-performance microscope, and the sample whose section is to be mirror-polished And the positional relationship between the mask and the mask can be set with high accuracy.

  Hereinafter, embodiments of the ion milling apparatus of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following examples.

  FIG. 1 shows the configuration of an ion milling apparatus according to the present invention, where (a) is a plan view and (b) is a side view. (A) shows a state in which the sample mask unit body and the sample holder fixture are pulled out of the vacuum chamber, and (b) shows that the sample mask unit body and the sample holder fixture are installed inside the vacuum chamber. It shows the state. Below, the case where an argon ion beam is irradiated from an ion source is demonstrated.

  The current density of argon ions in the ion source 1 for argon ions is controlled by the ion source controller 7. The vacuum chamber 15 can be in a vacuum or atmospheric state by controlling the vacuum exhaust system 6 by the vacuum exhaust system controller 9 and can maintain the state.

  The sample holder fixture 5 is configured to be able to rotate and tilt at an arbitrary angle with respect to the optical axis of the argon ion beam, and the direction and angle of rotation are controlled by the sample fine movement control unit 8. By rotating and tilting the sample holder fixture, the sample fixed to the sample holder can be set at a predetermined angle with respect to the optical axis of the ion beam. Moreover, it is preferable that the sample holder fixture 5 is configured to be movable in the front-rear and left-right directions, that is, in the X direction and the Y direction, with respect to the optical axis of the argon ion beam.

  The sample holder fixture 5 is fixed to a flange 10 that also serves as a part of the container wall of the vacuum chamber 15. When the flange 10 is pulled out along the linear guide 11 and the vacuum chamber 15 is opened to the atmospheric state, the sample holder is fixed. The fixture 5 is configured to be pulled out of the vacuum chamber.

  A sample mask unit main body 21 in which the positional relationship between the mask 2 and the sample 3 is finely adjusted in advance is attached to the sample holder fixture 5. The loupe arm 14 is rotated by using the loupe 12 having the loupe fine movement mechanism 13 for adjusting the focus as a rotation axis provided on the flange 10 and moved to a predetermined position, that is, the optical axis of the argon ion beam. Using the XY moving mechanism of the sample holder fixture 5, the portion of the sample 3 to be cross-polished is moved to the center of the XY memory attached to the loupe. Then, ion milling is performed by irradiating the sample 3 with an argon ion beam in a vacuum state.

  The configuration of the sample mask unit main body will be described with reference to FIG. 2A is a plan view, and FIG. 2B is a side view. In the present invention, at least the sample holder 23 and its rotation mechanism, and the mask 2 and its fine adjustment mechanism are integrally configured as a sample mask unit main body. In FIG. 2, a sample holder rotating ring 22 and a sample holder rotating screw 28 are provided as a rotating mechanism of the sample holder 23 so that the sample holder can be rotated perpendicularly to the optical axis of the ion beam.

  The sample mask unit main body 21 has a mechanism that can finely adjust the position and rotation angle of the mask, and can be attached to and detached from the sample holder fixture 5.

  The mask 2 is fixed to the mask holder 25 by a mask fixing screw 27. The mask holder 25 is moved along the linear guide 24 by operating the mask fine adjustment mechanism 26, whereby the positions of the sample 3 and the mask 2 are finely adjusted. The sample holder 23 is inserted and fixed to the sample holder rotating ring 22 from the lower side. The sample 3 is bonded and fixed to the sample holder 23. The position of the sample holder 23 in the height direction is adjusted by the sample holder position control mechanism 30, and the sample holder 23 is brought into close contact with the mask 2.

  The sample holder rotating ring 22 is configured to rotate by turning the sample holder rotating screw 28, and the reverse rotation is returned by the spring pressure of the spring 29.

  FIG. 3 is an explanatory view showing a method of making the cross section of the sample and the mask parallel to each other.

  The sample holder rotating screw 28 is turned to adjust the position in the X1 direction, and fine adjustment is performed under the microscope so that the cross section of the sample 3 and the ridge line of the mask 2 are parallel. At this time, the mask fine adjustment mechanism 26 is set to rotate so that the cross section of the sample 3 slightly protrudes from the mask, for example, approximately 50 μm.

  FIG. 4 is an explanatory view showing a method of aligning the portion of the sample 3 whose section is to be polished with the center of the argon ion beam. A photosensitive paper or the like is attached to the sample holder 23, and the trace formed by irradiating the argon ion beam, that is, the center of the beam and the center of the loupe are driven by the loupe fine movement mechanism 13 to drive X2 and X3. The sample mask unit main body 21 after fine adjustment in FIG. 3 is attached to the sample holder fixture 5, and the position of the sample holder fixture 5 in the X3 and Y3 directions is adjusted to match the center of the loupe. The part which wants to carry out cross-sectional polishing can be match | combined.

  FIG. 5 is an explanatory view showing a method of mirror-polishing the cross section of the sample 3 with an argon ion beam. When the argon ion beam is irradiated, the sample 3 not covered with the mask 2 can be removed along the mask 2 in the depth direction, and the surface of the cross section of the sample 3 can be mirror-polished.

  In recent years, particularly in the semiconductor field, it has become important to observe a cross-section of a composite material with an electron microscope, and the importance of mirror-polishing the cross-section of the composite material has increased. According to the present invention, it is possible to easily and accurately set a mask at a site where a cross section of a sample is desired to be observed. In the present invention, if a plurality of mask sample unit main bodies are provided, it is possible to prepare a large number of samples in a state where the mask position is finely adjusted in advance, which is very efficient. Further, according to the present invention, it is possible to observe an image with an electron microscope while the sample is attached to the sample holder.

It is a schematic block diagram of the ion milling apparatus by one Example of this invention. It is a schematic block diagram of a sample mask unit main body. It is explanatory drawing which showed the method of making the cross section of a sample and a mask into parallel. It is explanatory drawing which showed the method to match | combine the argon ion beam center and the site | part which wants to grind | polish the cross section of a sample. It is explanatory drawing which showed the sample cross-section grinding | polishing method by ion milling.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Ion source, 2 ... Mask, 3 ... Sample, 5 ... Sample holder fixture, 6 ... Vacuum exhaust system, 7 ... Ion source control part, 8 ... Sample fine movement control part, 9 ... Vacuum exhaust system control part, 10 ... Flange, 11 ... Linear guide, 12 ... Loupe, 13 ... Loupe fine movement mechanism, 14 ... Loupe arm, 15 ... Vacuum chamber, 21 ... Sample mask unit body, 22 ... Sample holder rotating ring, 23 ... Sample holder, 24 ... Linear guide , 25 ... Mask holder, 26 ... Mask fine adjustment mechanism, 27 ... Mask fixing screw, 28 ... Sample holder rotating screw, 29 ... Spring, 30 ... Sample holder position adjustment mechanism.

Claims (5)

  An ion source for irradiating a sample fixed to the sample holder with an ion beam, a sample holder fixture for fixing the sample holder, and a part of the sample fixed to the sample holder so that the ion beam is not irradiated A mask for shielding, a sample holder rotating mechanism for rotating the sample holder in order to align the processed part of the sample with the optical axis of the ion beam, and a mask fine adjusting mechanism for adjusting the positional relationship between the mask and the sample. An ion milling device configured to perform ion milling in a vacuum chamber, wherein the sample holder and its rotation mechanism, and the mask and its fine adjustment mechanism are integrally formed. A mask unit main body, the sample mask unit main body being removable from the sample holder fixture, and the vacuum chamber Ion milling apparatus characterized by being configured to be able to take out to the outside.   2. The sample holder fixture moving mechanism configured to move the sample holder fixture in a direction transverse to the optical axis of the ion beam, and the sample holder fixture with respect to the optical axis of the ion beam according to claim 1. An ion milling apparatus comprising at least one of a sample holder fixture rotating and tilting mechanism capable of tilting at an arbitrary angle.   An ion source for irradiating a sample fixed to the sample holder with an ion beam, a sample holder fixture for fixing the sample holder, and a part of the sample fixed to the sample holder so that the ion beam is not irradiated A mask for shielding, a sample holder rotating mechanism for rotating the sample holder in order to align the processed part of the sample with the optical axis of the ion beam, and a mask fine adjusting mechanism for adjusting the positional relationship between the mask and the sample. An ion milling device configured to perform ion milling in a vacuum chamber, wherein the sample holder and its rotation mechanism, and the mask and its fine adjustment mechanism are integrally formed. It has a mask unit body, and the sample mask unit body and the sample holder fixture can be taken out of the vacuum chamber. Ion milling apparatus characterized by being.   4. The sample holder fixture moving mechanism capable of moving the sample holder fixture in a direction transverse to the optical axis of the ion beam; and the sample holder fixture with respect to the optical axis of the ion beam. An ion milling apparatus comprising at least one of a sample holder fixture rotating and tilting mechanism capable of tilting at an arbitrary angle.   5. The ion milling apparatus according to claim 4, wherein the sample holder fixture is fixed to a flange that also serves as a part of the vacuum chamber, and the flange is configured to be pulled out of the vacuum chamber.

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