JP3693318B2 - X-ray variable perspective angle fluoroscope - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluoroscopic imaging apparatus using X-rays.
[0002]
[Prior art]
Recently, with the miniaturization and high density of electronic circuits, there has been an increasing demand for perspective observation of specific points that are considered defective for analysis of defects in electronic parts and LSI chip joints. In order to see through a specific point from multiple directions, conventionally, for example, as shown in FIG. 8, the X-ray source 1 and the X-ray imaging unit 7 are attached to an integral C-shaped frame 30 and the C-shaped frame 30 is centered on an axis 21 passing through the measurement point P. Thus, a method of tilting and rotating in the direction of reference symbol E is known . However, in this method, when the oblique angle is increased, the lower end corner portion 31 of the X-ray source 1 interferes (contacts) with the object 2 to be measured, so that the X-ray emission point cannot be brought close to the portion to be measured, and high-magnification observation is not possible. There is a serious drawback that the magnification is determined by the ratio of the X-ray emission point, the object to be measured, and the X-ray imaging unit. There is also a problem that the apparatus becomes large. As another conventional method, as shown in FIG. 9, a transmission X-ray having a large X-ray exit angle is used for the X-ray source 1, and only the X-ray image pickup unit 7 is moved on a radius centered on the X-ray output point (of the X-ray image pickup unit 7). There is a method in which the measured point P is positioned on a line connecting the X-ray emission point 40 and the X-ray imaging unit 7 and observed from a desired tilt direction. This method has the advantage that the X-ray source 1 and the DUT 2 can be brought close to each other and a high magnification can be obtained, but there is a serious drawback that the X-ray magnification is changed by changing the tilt angle of the X-ray imaging unit. It was.
[0003]
[Problems to be solved by the invention]
As described above, in the conventional technique, when the point to be measured is observed through a different perspective angle, a large enlargement ratio cannot be obtained, or the perspective angle cannot be changed while maintaining a constant magnification. There are drawbacks.
The object of the present invention is to eliminate these drawbacks, obtain a large magnification, and the magnification does not change even if the perspective angle is changed. Further, it is an object of the present invention to implement this with a simple mechanism.
[0004]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention achieves the above-mentioned transmission X-ray source, an XY stage that positions the object to be measured in the horizontal direction below the X-ray source, and a Z that positions the XY stage in the vertical direction that is the magnification direction. A stage is provided, an X-ray imaging unit below the XY stage, an imaging unit linear movement stage that linearly moves the imaging unit in the horizontal direction, and the X-ray detection surface always moves the X-ray emission point along with the operation of the linear movement stage. A variable perspective angle fluoroscopic imaging device is configured with an imaging unit tilting mechanism that tilts the X-ray imaging unit and an imaging unit rotation mechanism that rotates the imaging unit around a vertical line passing through the X-ray emission point.
More specifically, this operation will be described with reference to FIGS.
In both figures, 1 is an X-ray source, 2 is an object to be inspected (for example, a high-density mounting printed circuit board), and 7 is an X-ray imaging unit.
A case where observation is performed while changing the tilt angle α with respect to the vertical line (Z-axis) (that is, a change in viewing angle in the X-axis-Z-axis or Y-axis-Z-axis plane) will be described with reference to FIG. The measurement point P of the measurement object 2 is positioned on the XY stage at a position corresponding to the desired inclination α direction from the X-ray emission point of the X-ray source 1, and the X-ray imaging unit 7 is positioned in this emission direction. Further, according to this position, the X-ray detection surface 19 of the X-ray imaging unit 7 is inclined (angle β) so that the X-rays are incident vertically. In this way, fluoroscopic observation is performed.
Next, the case where observation is performed with the angle θ with respect to the X axis being changed will be described with reference to FIG. In this case, the measurement point P of the measurement object 2 is positioned at a desired position (x1, y1) with respect to the X axis on the XY stage, and the X-ray imaging unit is on a straight line connecting this position and the X-ray emission point O. The X-ray imaging unit 7 is positioned by the linear movement mechanism 7 and the imaging unit rotating mechanism (both not shown), and the X-ray detection 19 is tilted by the imaging unit tilting mechanism according to this position, and the fluoroscopic observation is performed from a desired angle. It is what I did.
[0005]
An embodiment of the present invention will be described below with reference to FIGS. 3 is a front view of the embodiment of the present invention, FIG. 4 is a side view of the same, and FIG. 5 is a plan view of the X-ray imaging unit 7 and the imaging unit linear movement stage 13. In both figures, the imaging units indicated by dotted lines show the states when they have moved. Reference numeral 1 denotes a transmissive X-ray source having an irradiation angle of 130 degrees. There is an XY stage below the X-ray source 1, and a high-density mounting substrate as the DUT 2 is fixed to the XY stage 3. The XY stage 3 is assembled to a Z stage 4 that is positioned in the vertical (Z-axis) direction. The Z axis stage is arranged at the four corners of the XY stage. By the action of the Z axis, when the X-ray source 1 and the DUT 2 are closest, the distance is 0.5 mm, and when the X-ray source 1 is farthest, it is 150 mm. The magnification is the maximum when it is closest, and the minimum when it is farthest. In the case of the current X-ray source, the magnification can be several times to 1000 times. Reference numeral 41 denotes an X-ray protective cabinet. 6 and 7 schematically show the motion of each stage. In both figures, only the operating part of the apparatus of the present embodiment is shown, and other structures are omitted.
[0006]
This will be described in detail below with reference to FIGS. Below the XY stage 3 is an X-ray imaging unit 7 which is composed of an X-ray image intensifier (hereinafter referred to as II tube) 5 for converting an X-ray image into a light image and a TV camera 6 for converting the X-ray image into an electric signal. It is arranged. The X-ray imaging unit 7 is rotatably mounted on the frame 10 by the rotation support unit 9 (the rotation direction is indicated by reference sign D in FIGS. 6 and 7). As shown in FIG. It is fixed to a worm gear 12 that is driven by a motor 11. As shown in FIG. 5, the frame 10 is attached to the table 14 of the imaging unit linear movement stage 13 and moves in the direction of reference sign B. As shown in FIG. 4, the imaging unit linear movement stage 13 is fixed to a rotating shaft 17 on which a worm gear 16 driven by a motor 15 is assembled. As shown in FIGS. 6 and 7, the imaging unit linear movement stage 13 rotates in the direction of the reference symbol C around the rotation shaft 17. Next, the relationship among the X-ray emission point O, the measured point P, the X-ray II5, the inclination angle α and the rotation angle θ will be described with reference to FIG. 1 which is a longitudinal section of the main part and FIG. When observing the measured point P from the directions of α and θ at the magnification A, first, the Z stage 4 (FIGS. 6 and 7) is such that the measured point P is on a plane including T where A = L / Z. Refer to) for positioning. Next, positioning is performed on the XY stage so that the point P to be measured comes to a point (x1, y1) that forms an angle α with respect to a perpendicular passing through the X-ray exit point O and forms an angle θ with respect to the X axis. At this time,
[Expression 1]
A = L / Z (2)
[Expression 2]
tan θ = y1 / x1 (4)
To satisfy. next,
r / Z = R / L (5)
The X-ray II5 is positioned at a point Q that satisfies the above and θ, and the X-ray detection surface 19 of the II tube 5 is made to X-ray by the II tube tilting mechanism 18 constituted by the worm gear 12, the motor 11, and the rotation support portion 9 according to this position. Position it so that it faces the exit point O.
[0007]
In the above description, the method of operating each positioning mechanism so as to simultaneously determine the inclination angle α and the rotation angle θ after determining the magnification A is described. However, after the magnification A is determined, the rotation angle θ is determined. Observing by changing the inclination direction α one after another, of course, after this observation is finished, it is of course possible to determine the inclination angle α and change the rotation direction θ one after another. Further, it is possible to perform defect analysis by determining the observation directions α and θ, changing only the magnification, and magnifying and observing the defective portion gradually. In this case as well, the relationship between the positions shown in equations (1) to (5) may be maintained. The calculation and operation command for each position depends on a computer and a control device (not shown), but this can be constituted by a publicly known personal computer and a numerical control board.
[0008]
【The invention's effect】
As described above, according to the present invention, the conventional X-ray inspection apparatus is provided with a mechanism for horizontally moving the X-ray imaging unit, inclining the X-ray detection surface accordingly, and rotating the X-ray imaging unit together with the horizontal movement mechanism. Thus, the measurement point can be inspected from a desired direction without changing the enlargement magnification from both the tilt direction and the horizontal rotation direction.
In addition, this function adds a X-ray imaging unit linear movement mechanism and tilt mechanism rotation mechanism to the conventional X-ray source, X-ray imaging unit, measurement object positioning XYZ stage, and only positions them in a certain geometric positional relationship. Therefore, it can be realized at a relatively low size and at a low cost.
[Brief description of the drawings]
1 is a front view showing a basic configuration of an embodiment of the present invention. FIG. 2 is a side sectional view showing a basic configuration of an embodiment of the present invention. FIG. 3 is a front view showing an embodiment of the present invention. FIG. 5 is a plan view showing an embodiment of the present invention. FIG. 6 is a schematic explanatory view of an embodiment of the present invention. FIG. 7 is a schematic view of an embodiment of the present invention. Explanatory drawing [FIG. 8] Explanatory drawing of conventional example [FIG.
1: X-ray source, 2: measured part, 3: XY stage, 4: Z stage, 5: X-ray image intensifier, 6: TV camera, 13: imaging unit linear movement mechanism, 18: imaging unit tilting mechanism, 19 : Imaging unit rotation mechanism

Claims (2)

  An X-ray source for generating X-rays, an XY stage for positioning a measurement object in the horizontal direction below the X-ray source, a Z stage for positioning the XY stage in a vertical direction, and an X-ray imaging provided at the lower part of the XY stage And an imaging unit linear movement stage that linearly moves the imaging unit in a horizontal direction, and an X-ray detection surface of the imaging unit is always inclined toward the X-ray emission point of the X-ray source in accordance with the operation of the linear movement stage. An X-ray variable perspective angle fluoroscopic device, comprising: an imaging unit tilting mechanism that rotates and an imaging unit rotation mechanism that rotates the imaging unit linear movement stage. A transmission X-ray source that radiates X-rays, an XY positioning means that is disposed below the X-ray source and positions in the horizontal direction of the measurement object, a Z positioning means that positions the XY positioning means in the vertical direction, and an XY positioning means An X-ray imaging means for taking an X-ray image, an imaging unit linear moving means for linearly moving the X-ray imaging means in the horizontal direction, and an X-ray of the X-ray imaging means in accordance with the linear movement of the imaging unit Imaging section tilting means for directing the detection surface in the direction of the X-ray source, and imaging section rotation for rotating the imaging section linear moving means, the imaging section tilting means and the X-ray imaging means about a vertical line passing through the X-ray emission point of the X-ray source An X-ray variable perspective angle fluoroscopic device comprising means.

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