JP2008027614A - Incident angle monitor element of charged particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an incident angle monitor element of charged particles in an ion beam device using a silicon plate with an opening formed and a silicon plate with a line-space pattern formed. <P>SOLUTION: The incident angle monitor element is composed of a member having an opening for passing the charged particles and a member having a face to irradiate charged particles forming a pattern structure for measuring a size, and has these arranged through a gap. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an evaluation sensor for evaluating the state of an apparatus in a device manufacturing apparatus such as a magnetic disk head.

  In the manufacturing process of a magnetic disk head whose density is increasing, a process apparatus is required to have high processing accuracy, and it is necessary to always grasp the state of the apparatus and maintain a good state. In particular, in an ion beam processing apparatus, it is known that a processing dimensional error due to beam expansion becomes a problem, resulting in a decrease in product yield. Since the device status changes with time, the conventional method is to inspect the actual wafer as appropriate in the manufacturing process, grasp the device status from the processing shape and characteristic inspection results, and feed back to the device status management. Was common.

  However, in the conventional method, there is a problem that when a defect occurs because an actual sample is used, a large cost is required and it takes time until feedback. Moreover, even if a dedicated sample is used for testing, the same cost and time are problems.

In order to solve this, as a method for detecting the state of the ion beam, a method of detecting the ion beam current distribution by arranging a beam sensor composed of a beam passing microhole and a conductor at the sample position (Patent Document) 1) and a method of measuring a beam shape with high accuracy by detecting a charged particle passing through a shape measuring apparatus having a sharp edge and a blocking portion while moving in a direction perpendicular to the beam (see Patent Document 2). Has been devised.
JP-A-6-162975 JP 2003-14347 A

  However, the ion beam state detection method disclosed in Patent Document 1 is difficult to measure the problem of beam spread and is difficult to apply to a manufacturing apparatus that processes the entire wafer surface. Further, Patent Document 2 is applicable only to measurement of a small beam having a beam diameter of the order of microns or less, and is not applicable to a manufacturing apparatus that processes the entire wafer surface. In addition, even if measurement is possible, since it is necessary to incorporate a measurement structure into the apparatus, there is a problem that the consistency with the manufacturing apparatus is poor.

  Therefore, the present invention provides an evaluation element that can directly measure the spread of an ion beam in an ion beam apparatus without changing the apparatus.

  A first invention is an incident angle monitor element for monitoring a spread amount of charged particles in a processing apparatus using charged particles, the first member having an opening for allowing the charged particles to pass through, and the charged A second member having a surface for irradiating the charged particles on which a pattern for measuring the spreading dimension of the particles is formed, and the first member and the second member are disposed with a gap interposed therebetween. The present invention relates to an incident angle monitor element.

  That is, according to the first invention, the incident angle monitor element includes a first member provided with an opening for allowing charged particles to pass through, and a second member provided with a pattern for measuring the amount of spread of the charged particles. The upper and lower surfaces are bonded to each other via a gap so that the charged particles that pass through the upper opening are irradiated onto the lower pattern, and after being put into the device, they are taken out and monitored for processing traces on the irradiated pattern. By doing so, the beam spread of the charged particles can be easily known, and the state of the charged particles emitted in the processing apparatus using the charged particles can be directly monitored at the process site.

  The second invention relates to the incident angle monitoring element according to the first invention, wherein at least one of the first member and the second member uses silicon as a material.

  That is, according to the second invention, by applying microfabrication on a silicon substrate, it is possible to secure micron-order machining accuracy that is difficult to achieve by machining, so that the same measurement accuracy is realized. . Further, since the positional accuracy by the combination of the two members can be achieved at a level that cannot be realized by the combination of the machined parts, the position shift amount of the machining pattern with respect to the opening can be accurately observed.

  According to a third aspect of the present invention, the pattern formed on the second member includes a repetitive pattern having a predetermined pitch of a line space or a concentric shape. The present invention relates to an incident angle monitor element.

  That is, according to the third invention, the pattern for measuring the amount of beam expansion formed on the second member is a continuous pattern having a predetermined pitch, for example, a concentric circle shape, a lattice shape, or a line / space shape. By adopting a structure in which the unit pattern dimensions are clarified by using a repetitive pattern, the dimensions of the shape processed by charged particle irradiation after the introduction of the apparatus can be easily confirmed visually, which is large for the operator of the ion beam apparatus. It will give convenience.

  According to a fourth aspect of the present invention, there is provided the structure according to any one of the first to third aspects, wherein the first member has a structure capable of removing a part of the substrate forming the opening. The present invention relates to a corner monitor element.

  That is, according to the fourth aspect of the present invention, a configuration is adopted in which a notch or the like is made in a part of the substrate forming the opening disposed at the upper portion, and the part forming the opening can be easily deleted. Therefore, after being put into the apparatus, a part of the cutout provided in the first member can be removed to expose the pattern part irradiated with the charged particles, and irradiation traces in the pattern part can be observed. It becomes extremely easy.

  A fifth invention relates to the incident angle monitor element according to any one of the first to fourth inventions, wherein a plurality of the incident angle monitor elements are formed and used as a single unit.

  That is, according to the fifth invention, since a large number of incident angle monitoring elements are formed in the same substrate surface such as a silicon wafer, distribution in the substrate surface can be measured. Also, by using silicon process technology, the upper first member and the lower second member can be accurately aligned, and the relative position between the opening and the pattern forming part such as a line and a space. Can be accurately arranged, the beam shift amount can be evaluated.

  As described above, according to the present invention, it is possible to directly observe the state of a manufacturing apparatus such as an ion beam processing apparatus at a low cost, thereby greatly reducing the number of evaluation steps related to establishment of apparatus conditions and apparatus state management, leading to cost reduction. At the same time, the yield can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of a basic structure of an incident angle monitor element for charged particles according to an embodiment of the present invention. The embodiment is an example of the structure of an incident angle monitor element that is inserted into the ion beam apparatus using charged particles to monitor the state of the ion beam apparatus and checks the beam spread of the charged particles irradiated to the measurement sample. It is shown. 1A is a top view of the incident angle monitor element, and FIG. 1B is a cross-sectional view of a plane passing through the vicinity of the opening.

  The incident angle monitoring element of the present invention includes a first member 1 in which an opening 12 for allowing charged particles to pass through a thin membrane portion 11 and a pattern forming portion 21 for evaluating beam spread of the charged particles. The second member 2 is joined to the top and bottom. In the present embodiment, the first member 1 and the second member 2 are both shown as examples in which silicon is used as a material. However, the present invention is not limited to this, and a desired structure is used. Any material can be used as long as it is excellent in workability in realizing it.

  Furthermore, several openings 12 for allowing charged particles to pass therethrough are formed in the first member 1 at the top. In this case, notches 13 are provided for crushing after introduction into the ion beam device and for monitoring. Is provided. The region where the opening 12 is formed (membrane portion 11) has a thickness as thin as 20 μm, for example. In the second member 2 in the lower part, a pattern composed of a line and a space structure is formed in the X direction and the Y direction in the pattern forming part 21, respectively. It is arranged directly under the opening 12 of the member 1.

  The incident angle monitor element has, for example, a dimension of the opening 12 of φ100 μm, a distance between the opening 12 and the surface of the lower second member 2 of 450 μm, and a line of the lower second member 2. The space shape is 5 μm wide.

  FIG. 2 shows the relationship between the beam incident angle and the spread amount in the incident angle monitor element for charged particles according to the embodiment of the present invention. In the embodiment, the amount of spread of the beam diameter with respect to the incident angle (expansion angle from the vertical axis with respect to the surface of the second member 2) when the charged particles are incident on the pattern forming portion 21 in the second member 2 below. Show. However, an example is shown in which the distance between the lower surface of the membrane portion 11 of the upper first member 1 and the surface of the second member 2 is 450 μm. In the case of this design dimension, the detection sensitivity of the beam incident angle can be ensured to be 0.5 degrees or less. Of course, when higher detection sensitivity is required, it is possible to cope with this by making the line and space intervals smaller.

  FIG. 3 shows an example of the shape of a charged particle incident angle monitor element wafer according to an embodiment of the present invention. Further, FIG. 4 shows an irradiation state when the membrane is peeled off after the device is introduced in the incident angle monitor element according to the embodiment of the present invention. A large number of the incident angle monitoring elements are formed in the silicon wafer as shown in FIG. The sensor is processed by putting this silicon wafer into an apparatus to be evaluated and performing a beam irradiation process. The wafer after the introduction of the apparatus is taken out, and as shown in FIG. 4, the thin membrane portion 11 is cut along the notch 13 on the upper surface of the incident angle monitor element, and the shape of the line and space irradiated with the charged particles immediately below the opening portion 12 Can be directly observed by means such as an optical microscope. As a result, it is possible to easily measure the dimensions of the processing region based on the pre-processed line and space pattern.

  In addition, since silicon is used as the material for the upper first member 1, if an infrared microscope is used, the processing dimension can be directly measured without removing the notch 13 of the first member 1. Is possible. Furthermore, if the dimension value and the angle value converted into the incident angle are described in the vicinity of the line and space pattern, the operator can more easily evaluate the apparatus characteristics.

  In addition, since a large number of incident angle monitoring elements are formed in the wafer surface as shown in FIG. 3, it is possible to measure the distribution in the wafer surface and use the silicon process technology to achieve the first The alignment between the member 1 and the second member 2 below can be performed accurately, and the relative position between the opening 12 and the pattern forming unit 21 such as a line and a space can be accurately positioned. It is also one of the features of the present invention that the evaluation can be performed.

  Below, the manufacturing method of the incident angle monitor element of the charged particle mentioned above is demonstrated using FIGS.

FIG. 5 shows a procedure for producing the first member layer in the incident angle monitor element according to the embodiment of the present invention. The present embodiment deals with an example in which silicon is applied as the substrate of the first member layer.
Process 1: A 6-inch silicon substrate having a thickness of 625 μm is prepared. It is also possible to use an SOI (Silicon on Insulator) substrate.
Process 2: A resist pattern is formed on the surface of the silicon substrate, and a circular opening 12 pattern and a notch 13 pattern are formed by dry etching using SF 6 gas. The depth is 20 μm.
Process 3: A convex pattern is exposed on the periphery of the wafer on the back side in accordance with the pattern on the silicon surface, and the alignment convex part 14 is formed by wet etching using TMAH (Tetra-Methyl-Ammonium-Hydroxide). The height of the convex shape is about 150 μm. Further, the shape pattern of the back surface opening 15 is exposed on the back surface in accordance with the convex pattern in a state where the convex pattern region is protected with an oxide film, etc., and the back surface opening portion 15 is etched by wet etching with TMAH, thereby The first member 1 is completed.

FIG. 6 shows a procedure for producing the second member layer in the incident angle monitor element according to the embodiment of the present invention. Similarly, this embodiment deals with an example in which silicon is applied as the substrate of the second member layer.
Process 1: A 6-inch silicon substrate having a thickness of 625 μm is prepared.
Process 2: A line and space pattern with a pitch of 5 μm is exposed, and a line and space pattern shape is formed by dry etching with SF6. The depth is about 1 μm.
Process 3: A concave pattern is exposed on the periphery of the wafer in accordance with the line and space patterns, and the shape of the alignment concave portion 22 is formed by wet etching using TMAH. The height of the concave shape is about 150 μm. At this time, the already formed pattern region is protected with an oxide film or the like. Thereby, the lower second member 2 is completed.

  FIG. 7 shows an incident angle monitor element in which the first member and the second member according to the embodiment of the present invention are combined vertically. As shown in FIG. 7, the upper first member 1 and the lower second member 2 are combined and bonded by direct silicon bonding or eutectic bonding with Au (gold) or Al (aluminum) interposed. Join both members together. Thus, simple and accurate alignment is possible by combining the convex structure of the upper member (alignment convex part 14) and the concave structure of the lower member (alignment concave part 22).

  With the above procedure, a wafer of charged particle incident angle monitoring elements is completed.

  The completed incident angle monitor element wafer can be used as it is, and the elements are separated by dicing, and are incorporated into other wafers and parts, for example, in small elements and put into the apparatus. Can also be evaluated.

  Note that the upper first member 1 is not limited to a silicon material, and it is also possible to use, for example, a glass material that is compatible with a micromachining process.

  FIG. 8 shows a repetitive pattern example formed on the second member of the incident angle monitor element according to the embodiment of the present invention. Pattern 1 shows an example in which concentric circular patterns are repeatedly formed, pattern 2 shows an example in which rectangular patterns are repeated in a lattice pattern, and pattern 3 shows an example in which lines and spaces having different widths are repeated. . Since all of these patterns have clear unit pattern dimensions, the dimensions of the shape processed by irradiation of charged particles after the introduction of the apparatus can be easily confirmed visually. Of course, the pattern shape is not limited to the above-described example, and needless to say, the pattern shape may be any pattern that can be visually confirmed.

It is a figure which shows the example of 1 basic structure of the incident angle monitor element of the charged particle which becomes embodiment of this invention. It is a figure which shows the relationship between the beam incident angle and the amount of spread in the incident angle monitor element of the charged particle which becomes embodiment of this invention. It is a figure which shows the example of a shape of the wafer for incident angle monitor elements of the charged particle which becomes embodiment of this invention. It is a figure which shows the irradiation condition at the time of peeling off a membrane after apparatus introduction in the incident angle monitor element which becomes embodiment of this invention. It is a figure which shows the preparation procedures of the 1st member layer in the incident angle monitor element which becomes embodiment of this invention. It is a figure which shows the preparation procedures of the 2nd member layer in the incident angle monitor element which becomes embodiment of this invention. It is a figure which shows the incident angle monitor element which combined the 1st member and 2nd member which become embodiment of this invention up and down. It is a figure which shows the example of a repeating pattern formed in the 2nd member of the incident angle monitor element which becomes embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st member 2 2nd member 11 Membrane part 12 Opening part 13 Notch 14 Alignment convex part 15 Back surface opening part 21 Pattern formation part 22 Alignment concave part

Claims (5)

An incident angle monitor element for monitoring the amount of spread of charged particles in a processing apparatus using charged particles,
A first member having an opening for passing the charged particles;
A second member having a surface for irradiating the charged particles on which a pattern for measuring the spread dimension of the charged particles is formed;
An incident angle monitor element, wherein the first member and the second member are disposed with a gap.   The incident angle monitor element according to claim 1, wherein at least one of the first member and the second member uses silicon as a material.   The incident angle monitor element according to claim 1, wherein the pattern formed on the second member includes a repetitive pattern having a predetermined pitch of a line space shape or a concentric shape.   4. The incident angle monitoring element according to claim 1, wherein a part of the substrate forming the opening in the first member is removable.   The incident angle monitor element according to any one of claims 1 to 4, wherein a plurality of the incident angle monitor elements are formed and used integrally.

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