JPH03130693A - X-ray image sensor - Google Patents

Abstract

PURPOSE:To stably detect X-rays by providing a groove for embedding an element to a substrate to perform the fixing and electrical connection of the element and bringing a shield plate into close contact with element. CONSTITUTION:A through-hole is provided to the bottom surface of a groove to which an element 1 is bonded and the electrical wiring to the conductive adhesive resin 3a on the rear of the element 1 is performed through the through- hole. A plurality of divided connection electrodes 2 are formed to the surface opposed to a shield plate 7 of the element 1 corresponding to the slits 8 of the shield plate 7. The element 1 functions as a plurality of X-ray elements in the substantially same number as the electrodes 2. The electrical connection to the electrodes 2 is performed by a conductor 10 and a conductive adhesive resin 3b as the common electrode on the rear of the element 1. The shield plate 7 is mounted to a grooved substrate 9 in parallel so that the slits 8 are opposed to the electrodes 2 through an insulating spacer 11. Therefore, the electrodes 2 can come into close contact with the shield plate 7 and both of them can be brought to an integrated structure.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an X-ray image sensor using a semiconductor radiation sensor. Although configured as shown in Figure 3, the element 1 sensitive to X-rays is made of a CdTe single crystal with a thickness of about 0.5 m, a hole of about 1 m in width, and a length of about 1 to 2 cm.
After polishing and etching the surface, the gold electrode 2 is formed by electroless plating (electrode 2 is
Even if it is formed with a vapor-deposited thin film of French gold or the like, it is better. 2, as shown in FIG. 3, a plurality of islands are formed on the element surface. On the back surface of the element 1, electrodes of the section are formed over the entire surface, facing oppositely to the connection electrodes, and forming one sensor section corresponding to each of the connection electrodes. Electrode ζ In this example,
Although it is of course possible to provide a configuration in which electrodes facing each other are provided independently from the connection electrode 2, the connection electrode 2 of the element 1 can also be formed as a common electrode. The sensor blocks shown in FIG. 3, which are connected by the electrode pattern 5 on the substrate 4 and the conductor 6 and configured like a duck, are arranged in series to form an array. Even if the voltage is applied between the upper and lower electrodes that face each other,
For such a sensor block, the slit 8C provided in the shielding plate 7 may be parallel to the connecting electrode 2 of the element 1 for detecting X-rays and supported by another member at a distance of about 0.5 mm. However, the above-mentioned conventional technology has the following problems.

In other words, when obtaining a diagnostic image using a conventional X-ray image sensor using a so-called fan beam that spreads out in a fan shape and enters the tx X-ray image sensor, the X-rays enter the slit of the shielding plate at a considerable angle of incidence. do. As mentioned above, since the shielding plate 7 and the element 1 are separated by a distance of about 0.5 mm, when the X-rays are obliquely incident on the slit as described above, the connection electrode corresponding to the slit is In order to be able to receive X-rays, the size of the connecting electrode must be larger than the size of the slit.
Or, if the connecting electrodes are made larger or the arrangement pitch is made smaller in order to increase the resolution, the amount of received X-rays will be reduced.
Signal leakage occurs between adjacent sensors, causing errors such as positional density changes in X-ray diagnostic images.Because the element 1 protrudes above the substrate 4, it is vulnerable to mechanical shock from the outside. There are many shortcomings: foreign matter can enter the gap between the shielding plate 7 and the element 1, reducing the reliability of the device. To solve the problem, Invention 1i A groove for embedding the element is provided in the substrate to fix the element and make electrical connection.\ The shielding plate is placed in close contact with the element and placed on the upper surfaces of both walls of the groove. The effect of the above means is as follows: Due to the above means, the shielding plate is disposed closely to the element, so that the size of the connecting electrode is L. Approximately the same size as the slit in the board can be used.

External placement: Elements embedded in grooves in the substrate are less susceptible to direct mechanical shock from the outside, and because the shielding plate and the element are in close contact, foreign objects cannot get into the space between them as in the conventional method. ~Example Examples of the present invention will be described below based on the drawings.

FIG. 1 shows the configuration of an X-ray image sensor according to an embodiment of the present invention. Figure 1 (above) shows a sensor block in which the element 1 is embedded in the grooved substrate 9 and fixed and electrically connected with the conductive adhesive resin 3a.A through hole is provided at the bottom of the groove where the element 1 is bonded. Electrical wiring to the adjoining citrus 3a on the back side of the element 1 is done through this through hole. The plurality of connection electrodes 2 and the conductive adhesive resin 3a as a common electrode on the back surface form a plurality of connection electrodes 2, which are substantially the same in number as the number of connection electrodes 2, from the element 1ζ. The electrical connection to the connecting electrode 2, which functions as an X-ray element, is made by the conductor 10, which is a gold-plated copper foil, and the conductive adhesive resin 3b. It is attached to the substrate 9 in parallel so that the slit 8 faces the connection electrode.Although ζL CdTe is used as the element 1, silicon, germanium, etc. may also be used.
).

Thickness of conductive adhesive resin 3b and conductor 10 (usually 50μ
m or less, and by selecting the thickness of the spacer 11 in accordance with this thickness, the distance between the element 1 and the shielding plate 7 (upper
The wiring to the connection electrode 2 can be made with a thickness of about 50 to 150 μm, for example
This is also possible by passing a thin wire through the slit 8 of the shielding plate 7 and bonding it to the connection electrode 2.

Figure 2 shows the configuration of an X-ray image sensor according to another embodiment of the present invention. Even though a plurality of independent connection electrodes similar to the connection electrode 2 in FIG. In this case, the shielding plate 7 acts as a common electrode for the connection electrodes provided on the back surface of the element 1 4 and the conductive adhesive resin 3 corresponds to the slit 8 . A plurality of the connection electrodes cL are formed independently on the back surface of the element 1, even though they are coated on the element 1 except for some parts.The electrode pattern 1 is formed on the substrate 14 using conductive adhesive resin or the like.
Even if the electrical connection is made to the shield plate 7, the insulating spacer 15 that forms the groove in which the element 1 is embedded is also bonded to the shield plate γζ, and the direct external force ζ applied to the shield plate 7 is also bonded to the spacer 15. 1, which is almost as good as element 1. With such a configuration, the distance between the shielding plate 7 and the element 1 can be made as small as about 5 to 20 μm, which is the thickness of the conductive adhesive resin 3.

In this case, a through hole corresponding to the connection electrode is provided at the bottom of the groove of the substrate.It is also possible to make an electrical connection to the connection electrode through this through hole by wire bonding.

As described in detail, according to the present invention, it is possible to bring the connecting electrode of the X-ray sensor and the shielding plate into close contact with each other, and also to form an integrated structure for the two. Even when the direction changes, sensitivity changes between the slits are not likely to occur, making stable X-ray detection possible.Also, foreign matter does not get between the element and the shielding plate, greatly improving the reliability of the device. Although it is easy to downsize the X-ray sensor array block, a configuration in which the shield plate of the X-ray sensor is also used as an electrode is possible.
It is more effective in terms of simplifying the sensor configuration.

[Brief explanation of the drawing]

Figure 1 °(y) A configuration diagram of a sensor array block of an X-ray image sensor in one embodiment of the present invention Figure 2 ζ A diagram of a configuration of a sensor array block in another embodiment of the present invention Figure 3 is a diagram of a conventional sensor array block It is a configuration diagram of a sensor array block of an X-ray image sensor. ■... Element, 2... Connection voltage ff13a, 3b.
Conductive adhesive resin 7... Shielding plate 8... Slit,
4, 9, 14...Substrate 10...Conductor 11, 15
...Insulating spacer, 5.13...Electrode pattern.

Claims (3)

[Claims] (1) An X-ray sensitive element, a substrate holding the element, and an X-ray sensor having a slit and arranged facing and parallel to the element.
An X-ray image sensor comprising: a radiation shielding plate;
The element is housed in a groove formed in the substrate, and the shielding plate is supported by upper surfaces of both walls of the groove. (2) A claim characterized in that the X-ray sensitive element is connected to a common electrode on the surface in contact with the groove bottom, and a plurality of divided electrodes are formed on the surface facing the shielding plate. The X-ray image sensor according to item 1. (3) The X-ray sensitive element is characterized in that a surface facing the shielding plate is electrically connected to the shielding plate, and a plurality of divided electrodes are formed on the surface in contact with the groove bottom. The X-ray image sensor according to claim 1.