JP2007232677A - Measuring position assigning method, and dimension measuring instrument for executing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correctly assign a measuring position of a pattern. <P>SOLUTION: This measuring position assigning method is a method for assigning the two-dimensional measuring position when measuring a two-dimensional dimension in case of viewing the pattern with layer structure formed at two or more of timings on a substrate, from a planar direction, and includes the first step for designing a layer image at the every timing to be pattern-collated with an actual object and for recording it, the second step for constitution-classifying graphic forms indicated respectively in the layer images recorded in the first step into one or a plurality of shape portions (components), and for imparting a component name to the each component, and the third step for assigning the measuring position of the pattern by the component name. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention captures a measurement target such as a semiconductor integrated circuit finely processed to a submicron order and an etching product associated therewith with an imaging device, processes the captured image, and lays out the measurement target at two or more times. The present invention relates to a method for designating a measurement position of a pattern and a dimension measurement apparatus for executing the method when measuring the dimension of a pattern formed in the above manner.

  When a pattern with a fine line width is generated by partially forming layers at different timings by an etching process, which is a semiconductor manufacturing process, on the substrate, since the pattern is fine, the width and spacing of each pattern Therefore, it is necessary to generate the shape dimension and the like with high accuracy without shifting the position.

  The patterns generated at such different timings are displaced due to differences in apparatuses that form the patterns, alignment errors, and the like. In the pattern formation process, the pattern may be formed to be thick or thin. For this reason, in such pattern formation, a pattern is captured by an imaging camera, image recognition is performed on a computer screen, and the pattern dimension is measured to grasp the pattern formation state (Patent Document 1).

  A method for specifying a measurement location for conventional dimension measurement will be described.

  First, the first substrate (actual) is imaged. A measurement location on the substrate is designated on the captured image. This designated location is registered in the template image. The measurement position in the template image is designated as coordinates and stored.

Next, another substrate (another actual object) is imaged. An image (matching image) having a shape matching the template image is searched from the images of the other substrates. The measurement position on the searched coincidence image is designated according to the stored measurement position data. However, in this designation method, the measurement position of another substrate pattern is different from that of the first substrate, so that it may not be correctly designated. Further, when the pattern design is repeatedly changed, it takes a lot of man-hours to re-instruct the measurement position.
Japanese Patent No. 3059602

  Therefore, the problem to be solved by the present invention is to be able to correctly specify the measurement position of the pattern. Further, it is to be able to specify the measurement position with a small number of man-hours even if pattern design changes are repeated.

  (1) The present invention is a method for designating a measurement position in two dimensions when measuring a dimension of a pattern formed with a layered structure on a substrate at a timing of two or more times. A first step of designing and recording a layer image (an image on which a pattern in the layer is formed) for pattern matching with a substrate on which a pattern is actually formed in a layer structure, and recording in the first step The pattern of the pattern shown in each layer image is divided into one or more shape parts (parts), and a second step of assigning a part name to each part, and the pattern measurement position by the part name And a third step of designating.

  According to the present invention, the patterns generated at different timings of the patterns of the respective real objects may be misaligned due to differences in apparatuses that form the patterns, or may be fat or thin. Since the pattern measurement position is designated by the part name, the pattern measurement position can be correctly designated. Further, even if the pattern design change is repeated, the measurement position can be easily specified without man-hours.

  (2) In the third step, an orthogonal two-dimensional XY coordinate having an arbitrary point of the layer image as a relative image origin is set, and the pattern is specified by specifying the relative coordinate of the shape portion corresponding to the part name using this coordinate. It is preferable to specify relative measurement positions.

  (3) In the third step, it is preferable to specify the measurement position of the pattern by a logical expression based on the part name corresponding to the measurement position.

  According to the present invention, since the measurement position of the pattern is specified by the part name, the pattern generated at a timing when each actual pattern is different may be shifted due to a difference in apparatuses for forming these patterns. Alternatively, the measurement position can be correctly specified even if it is fat or thin, and the measurement position can be specified with less man-hours even if the pattern design change is repeated.

  Hereinafter, a dimension measurement position designation method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing a schematic configuration of a dimension measuring apparatus used for carrying out the dimension measuring position specifying method of the embodiment. FIG. 1 shows the X-axis direction, the Y-axis direction, and the Z-axis direction. These axes are orthogonal to each other. With reference to these drawings, the dimension measuring device 2 includes an imaging device 4 for imaging a measurement object and a control device 6 with a computer that controls the imaging device 4. The imaging device 4 and the control device 6 are connected so as to be able to transmit information to each other.

  The imaging device 4 includes an imaging base 8 having a rectangular shape in plan view, which is long in the X-axis direction and constant in the Y-axis direction. A pair of guide rails 10 extending in parallel with each other in the X-axis direction are provided on the imaging base 8. A rectangular flat plate-shaped moving table 12 is movable in the X-axis direction on the pair of guide rails 10. An encoder head (not shown) is integrally installed on the moving table 12. The linear scale 14 provided along the guide rail 10 and the encoder constitute a linear encoder that measures the amount of movement of the moving table 12 in the X-axis direction.

  On the imaging base 8, a gate-type imaging base 16 is installed so as to straddle the movable table 12 in the Y-axis direction. The imaging platform 16 is provided with an area-type imaging device 18 as a camera mechanism and a high-speed autofocus mechanism 20 movably in the Y-axis direction as a camera movement mechanism (not shown). The camera moving mechanism integrally moves the area type image sensor 18 and the high-speed autofocus mechanism 20 to the X coordinate commanded from the control device 6. The area-type image sensor 18 has an objective lens like a microscope and includes a two-dimensional CCD image sensor. The imaging magnification can be changed by exchanging the objective lens.

  The substrate 22 is, for example, a glass substrate for a liquid crystal panel, and is positioned on the moving table 12 by a plurality of positioning pins 23 and a plurality of pushers 26.

  1 moves the area-type image sensor 18 in the X-axis direction and the Y-axis direction with respect to the substrate 22 by moving the moving table 12 and the imaging gantry 16 of the imaging device 4. An image of a predetermined portion above is taken, the image is taken into the control device 6, the dimension measurement position of the element formed on the substrate is designated by image processing in the control device 6, and the dimension at the designated measurement position is measured. Be able to.

  The control device 6 includes a keyboard and a display, sends a command to the imaging device 4, observes an image captured by the area-type imaging device 18 of the imaging device 4, and controls the imaging device 4. Can be entered. The computer program for dimension measurement for controlling the imaging device 4 may be installed in the computer of the control device 6 from the beginning, or may be downloaded from the outside via a network.

  The control device 6 is equipped with a computer program for executing the measurement position specifying method described below.

  FIG. 2 shows a photographed image of the substrate 22 (actual) by the area type image sensor 18. Such a photographed image shown in FIG. 2 is obtained by photographing each of the plurality of substrates. Each of the plurality of substrates is captured by the control device 6. The captured image shown in FIG. 2 shows an image in which a pattern is formed at two or more different timings. The pattern shown in the captured image of FIG. 2 is a semiconductor manufacturing technique that is performed several times, in this example, three times, so that the pattern having a fine line width on the order of submicron becomes three layers. It is formed. The captured image in FIG. 2 is an image of a substrate (actual) on which a pattern is actually formed in a layered structure.

  FIG. 3 shows a layer image designed and recorded for comparison with the actual object shown in FIG. 3A to 3C are layer images, and each layer image shows a pattern figure. The layer image in FIG. 3A is named as Ray1, the layer image in FIG. 3B is named as Ray2, and the layer image in FIG. 3C is named as Ray3. Each layer image of FIGS. 3A to 3C shows a pattern figure for each timing for collation with the real object. The figures shown in these layers 1, 2, and 3 are divided into one or more shape parts (parts). Each of these parts is given a part name.

  FIG. 4 shows a part name example of some of these part names. That is, in FIG. 4, ELE1 is a part name given to the shape part A of Ray2 in FIG. 3, and ELE2 and ELE3 are part names given to the shape parts B and C of Ray1 in FIG. The above part names are examples of part names, and can be given to each shape part constituting each of the patterns shown in FIGS. Relative coordinates for use in specifying the measurement position are attached to the parts shown in each of these layer images.

  FIG. 5 representatively shows the coordinates of the part ELE1 shown in the Ray2. That is, the coordinate image in FIG. 5 is a quadrilateral. In the quadrilateral diagram, the upper left corner where the left side and the upper side intersect is the image origin, the right side direction in the drawing along the upper side is the X relative coordinate, and the lower left side direction. Is the Y relative coordinate, the X, Y relative coordinate of the ELE 1 of the Layer 2 can be obtained. Similarly, the X and Y relative coordinates can be obtained for other parts as well. This image origin may be an arbitrary position, and is not limited to that in FIG.

  In the above, in each pattern of each layer image, there are portions that overlap each other in a direction perpendicular to the plane direction. This is because the layer structure constituting the actual pattern in FIG. 2 is overlapped, and the layer portion of each layer image designed and recorded correspondingly overlaps in the direction perpendicular to the plane direction. Exists.

  A case where the measurement position of the overlapping portion or the non-overlapping portion is specified for such a pattern having an overlapping portion will be described with reference to FIG. FIG. 6 shows a diagram in which Ray1, Ray2, and Ray3 are overlapped. As an example, this measurement position is a portion surrounded by a circle in FIG. 6 and indicated by a black “e” in katakana. This measurement position portion is a portion that does not overlap with ELE2 and ELE3 of Lay1 in ELE1 of Lay2. Therefore, the designation of the measurement position can be calculated by a logical expression of (ELE2orELE3) xorELE1 as a part name. or is a logical sum and xor is an exclusive logical sum. The above logical expression is an example, and this logical expression can be set by the overlapping state of the figures shown in the layer image. Designation of the measurement position for the overlapping portion and the non-overlapping portion in the other Ray1, Ray2, and Ray3 can be similarly designated by a logical expression corresponding to each.

  In the embodiment described above, even if the pattern of another board is different from the pattern of the first board, the measurement position of the pattern can be correctly specified because it is specified by the component name. Further, even if the pattern design change is repeated, the measurement position can be easily specified without man-hours.

  Further, even when there is a portion that overlaps each other in the direction perpendicular to the plane direction in the pattern of each layer image, the overlapping portion or the portion that does not overlap is designated as the measurement position for a plurality of parts corresponding to the overlapping portion. When the pattern measurement position is specified by a logical expression based on the part name corresponding to the measurement position, the patterns generated at different timings of the respective actual patterns are different from each other in forming the patterns. Even if there is a deviation, fatness, or thinning due to the above, the pattern measurement position can be correctly specified.

FIG. 1 is a diagram showing a schematic configuration of a dimension measuring apparatus used in an embodiment of the present invention. FIG. 2 is a diagram showing an actual photographed image photographed by the area type image sensor of the dimension measuring apparatus of FIG. FIG. 3 is a diagram showing each layer image for comparison with the actual object. FIG. 4 is a diagram showing some parts when the graphic shown in the layer image of FIG. 3 is divided into a plurality of parts. FIG. 5 is a diagram showing a coordinate image when the relative coordinates on the coordinate image of the component of FIG. 4 are obtained. FIG. 6 is a diagram in which a plurality of layer images are superimposed.

Explanation of symbols

2 Dimension Measurement Device 4 Imaging Device 6 Control Device 8 Imaging Base 10 Guide Rail 12 Moving Table 14 Linear Scale 16 Imaging Base 18 Area Type Image Sensor 22 Substrate Ray1, Ray2, Ray3 Layer Image ELE1, ELE2, ELE3 Parts

Claims (4)

A method for designating a measurement position in two dimensions when measuring a dimension of a pattern formed on a substrate at a timing of two or more times with a layered structure,
A first step of designing and recording a layer image (an image on which a pattern in the layer is formed) for pattern matching with an actual object (a substrate on which a pattern is actually formed in a layer structure);
A second step of dividing the figure of the pattern shown in each layer image recorded in the first step into one or a plurality of shape parts (components) and assigning a component name to each component;
A third step of designating the measurement position of the pattern by the part name;
A measurement position specifying method characterized by comprising:   The third step determines an orthogonal two-dimensional XY coordinate having an arbitrary point of the layer image as a relative image origin, and uses this coordinate to specify the pattern measurement position by specifying the relative coordinate of the shape portion corresponding to the part name. 2. The measurement position designation method according to claim 1, wherein relative designation is performed.   The measurement position designation method according to claim 1, wherein in the third step, the measurement position of the pattern is designated by a logical expression based on a part name corresponding to the measurement position.   A dimension measuring apparatus, comprising a computer program for executing each step of the measuring position specifying method according to any one of claims 1 to 3.