JPH01172792A - Radiation detector and is manufacture - Google Patents

Abstract

PURPOSE:To exactly and efficiently mount many elements by a construction wherein a shield plate for shielding light between each scintillator is provided and allowing the end of said shield plate to reach an insulating bonding material layer and be out of contact with a photodiode. CONSTITUTION:A protecting film 3 is formed on the underside of a scintillator 2, a transparent electrode 4 is installed on the protecting film 3 for detecting the generation of the scintillator 2, further, a P-type a-Si layer 5, an I-type a-Si layer 6 and N-type a-Si layer 7 are formed in order and lastly electrodes 2 are installed. An electric signal is obtained from electrodes 4, 8. A photodiode part, especially semiconductor parts 5-7 and the electrode 8 come in contact with a shield plate 1 for separating the scintillator 2 through an insulating bonding material layer 9 and both are placed apart each other electrically and spatially. Thus, at the time of incorporating the shield plate 1, a photodiode is not damaged. Further, the shield plate 1 is inserted and fixed in a groove 11 and crosstalk generated in the neighboring channels can be prevented because the light emitted from each scintillator does not reach the photodiode of the neighboring channel.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a radiation detector used in an X-ray CT device, etc., and a method for manufacturing the same, and in particular, to a radiation detector that has no crosstalk between adjacent channels and has a high SIN ratio. The present invention relates to a radiation detector with high detection sensitivity, no characteristic deterioration during mounting, and easy mounting, and a method for manufacturing the same.

[Conventional technology]

Solid-state detection elements for solid-state horizontal use for CT″fA are as follows:
There are some that combine a scintillator and a photodiode. Due to recent advances in applied research on amorphous materials, it is becoming possible to use an amorphous silicon photodiode as the photodiode. Literature related to this type of technology is as follows.

For example, JP-A-62-71881, JP-A-62-43
No. 585, No. 62-235588, and the like can be mentioned.

In addition, as a solid-state detector using a crystal photodiode, 1. There is one disclosed in Japanese Unexamined Patent Publication No. 60-263456.

As an example, the solid state detection element for CT apparatus disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 62-71881 will be described as follows.
In this solid-state detection element, a large number of radiation detection elements each having a photoelectric conversion element formed on at least the surface facing the radiation incident surface of the scintillator are arranged in a circular shape in close contact with each other.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, no consideration is given to the accurate and efficient mounting of multiple elements, and a large number of radiation detection elements are arranged in close contact in a circular shape, resulting in misalignment between adjacent elements. There was a serious problem that was easily overlooked. *Also, since the manufacturing process requires highly skilled technology, there is a problem in that the manufacturing cost becomes extremely high.

The present invention has been made in view of the above circumstances, and its purpose is to solve the above-mentioned problems in conventional radiation detectors and to enable accurate and efficient mounting of a large number of elements. An object of the present invention is to provide a radiation detector and a method for manufacturing the same.

[Means for solving problems]

The above-mentioned object of the present invention is to provide a radiation detection device in which a plurality of elements are integrated, which comprises at least a plurality of scintillators, a plurality of photodiodes formed in close contact with each of the scintillators, and a substrate supporting the scintillator group. In the device, the substrate is fixed to the scintillator and the photodiode with a substantially insulating adhesive, and a shielding plate for shielding light or radiation is present between each scintillator, A radiation detector characterized in that an end of the shielding plate reaches at least the insulating adhesive layer and does not touch the photodiode, and at least 1. In the method for manufacturing a radiation detector, in which a transparent electrode, an amorphous semiconductor layer, and an electrode are formed and fixed to a substrate using an insulating adhesive, a scintillator wafer is used as the scintillator, and at least the transparent After patterning an electrode, an amorphous semiconductor layer, and an electrode, and fixing them to a substrate with an insulating adhesive, a cut is made to a predetermined depth from the scintillator wafer side to form the scintillator.

Achieved by a radiation detector manufacturing method characterized by cutting a transparent electrode, an amorphous semiconductor layer, and an electrode into predetermined sizes, and inserting a shielding plate for shielding light or radiation into the cut. be done.

[Effect]

In the radiation detector according to the present invention, at least a transparent electrode, an amorphous semiconductor layer, and an electrode are patterned on a scintillator wafer, and after this is fixed to a substrate with an insulating adhesive, a predetermined pattern is formed from the scintillator wafer side. The scintillator, the transparent electrode,
Radiation detectors are manufactured by cutting the amorphous semiconductor layer and electrodes into predetermined sizes and inserting a shielding plate for shielding light or radiation into the cut, so a large number of scintillators can be used. , which can be handled in a regularly arranged form in advance, allowing for efficient implementation.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a sectional view showing the structure of a two-channel radiation detection element which is an embodiment of the present invention.

The scintillator 2 of the radiation detection element shown in this embodiment is, for example, a Gd2O□S ceramic scintillator, a CdW
O, crystal scintillator, the size of one element is, for example,
The size is 30mm x 3mm x 1mm.

A protective film 3 is provided on the bottom surface of the scintillator 2 as necessary.
(For example, a Si○2 transparent film) is formed, and on this protective film 3, an a-8i photodiode for detecting light emission from the scintillator is formed. That is, the transparent electrode 4 (for example, ITO, Sn○21 S n○2/IT02 layer film)
Furthermore, a p-type a-8i layer 5゜j-type a-3i layer 6
．． An n-type a-5i layer 7 is formed in sequence, and finally an electrode 8 is formed. Electric signals are obtained from the transparent electrode 4 and electrode 8.

The photodiode section, particularly the semiconductor sections 5 to 7 and the electrode 8, are in contact with the shielding plate 1 that separates the scintillator via an insulating adhesive layer 9, and are electrically and spatially separated from each other. . Therefore, the photodiode is not damaged when the shielding plate 1 is assembled, and the structure is such that deterioration of element characteristics during mounting is unlikely to occur. Shielding plate 1 for signal current
Another advantage is that no noise current is introduced through the circuit.

Further, the shielding plate 1 is inserted into and fixed to a groove 11 formed in a part of the scintillator 2 and the insulating adhesive layer 9, and prevents light emitted from each scintillator from reaching the photodiode of an adjacent channel. . This can prevent crosstalk between adjacent channels.

The structure of the shielding plate 1 may be, for example, a thin plate of tungsten or molybdenum (50 to 150 μm thick), and a light reflecting film may be formed on the surface of the thin plate if necessary. The space between the grooves 11 is made slightly wider (for example, 10 to 20 μm) than the thickness of the shielding plate 1.

The insulating adhesive layer 9 (for example, epoxy resin, etc.) is for the purpose of fixing the scintillator 2 and the photodiode group to the substrate 10, so that these detection element groups have an integrated structure. It is. Another purpose of the insulating adhesive layer 9 is to act as a protective film for the semiconductor layers 5 to 7 used in photodiodes. That is, the insulating adhesive layer 9 can prevent characteristic deterioration that occurs when the semiconductor layers 5 to 7 are left in the atmosphere.

Further, if an adhesive material that is opaque to scintillator light is used as the insulating adhesive layer 9, it is possible to remove even a slight amount of light that goes around into the adhesive material, thereby further reducing the above-mentioned crosstalk.

FIG. 2 shows another embodiment of the present invention, in which the shielding plate 1 is a scintillator 2. The insulating adhesive layer 9 is completely separated, and its tip reaches into the substrate 10. According to this structure, the number of crosses between adjacent elements can be further reduced.

Next, an example of a method for manufacturing the radiation detection element of the embodiment shown in FIGS. 1 and 2 will be described with reference to FIG. 3.

First, as shown in FIG. 3(a), a large number (two in the figure) of a-3i photodiodes are formed on - scintillator wafers 2a. Next, as shown in FIG. 3(b), the substrate 10 and the scintillator wafer 2a are bonded together using an insulating adhesive 9. As a result, the scintillator wafer 2
(a) has a significantly increased mechanical strength and can prevent damage to the scintillator in the subsequent cutting process. Further, the photodiode is also protected by the insulating adhesive 9.

An example of the element shape after the cutting process, which is the next process, is shown in the third
Shown in Figure (c). Cutting can be easily performed using, for example, a diamond cutter, wire saw, band saw, or dicing saw. Further, the positional accuracy of the groove 11 is determined by the accuracy of machining alignment, and an accuracy of about 5 to 10 μm can be easily obtained.

The shielding plate 1 is inserted and fixed into this groove 11. As a fixing method, for example, there is a method of fixing both ends of the shielding plate 1 with an adhesive. Furthermore, it is not impossible to pour a bonding agent into the shield plate insertion groove 11. In this way, Figures 1 and 2
A detection element having the structure shown in the figure can be manufactured.

FIG. 4 shows yet another embodiment of the present invention.

This example differs from the previous example in that a-3i
After forming the photodiode, an insulating protective film 12 (for example, PIQ or SiO□) is coated. According to this method, the insulating adhesive layer 9 does not necessarily need to be a completely insulating material. That is, the two-layer structure of the semiconductor protective film and the adhesive layer substantially functions as an insulating adhesive layer.

The feature of this embodiment is that since the a-8i film is protected by a protective film, deterioration of the characteristics of the photodiode portion can be prevented even if machining such as cutting is performed without waiting for the adhesion process. It also has the advantage of widening the selection range of adhesive materials.

〔Effect of the invention〕

As described above, according to the present invention, at least a transparent electrode, an amorphous semiconductor layer, and an electrode are patterned on a scintillator wafer, and after this is fixed to a substrate with an insulating adhesive, A cut is made to a predetermined depth, and the scintillator, transparent electrode, amorphous semiconductor layer, and electrode are cut to a predetermined size, and a shielding plate for blocking light or radiation is inserted into the cut. Since the radiation detector is manufactured, it is possible to realize a radiation detector and a method for manufacturing the same in which a large number of elements can be mounted accurately and efficiently, which is a remarkable effect.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of a two-channel radiation detection element according to an embodiment of the present invention, and FIG. FIG. 4 is a sectional view showing another embodiment of the present invention, and FIG.
) to (c) are cross-sectional views showing the structure of a two-channel radiation detection element at each stage of the manufacturing process, which is an embodiment of the present invention. 1: Shielding plate, 2: Scintillator, 3: Protective film, 4: Transparent electrode, 5: P-type a-8i film M, 6: I-type a-8i layer, 7: N-type a-8i layer, 8: Electrode , 9: Insulating adhesive (layer), 10: Substrate, 11: Groove. Figure 1 Figure 2 Figure 3 (a)

Claims (1)

[Claims] 1. A radiation detector integrated with a plurality of elements, which includes at least a plurality of scintillators, a plurality of photodiodes formed in close contact with each of the scintillators, and a substrate supporting the scintillator group, The substrate is fixed to the scintillator and the photodiode with a substantially insulating adhesive, and a shielding plate for shielding light or radiation is present between each scintillator, and the shielding plate is A radiation detector characterized in that an end portion reaches at least the insulating adhesive layer and does not touch the photodiode. 2. The radiation detector according to claim 1, wherein the shielding plate extends into the substrate. 3. A method for manufacturing a radiation detector, in which at least a transparent electrode, an amorphous semiconductor layer, and an electrode are formed on a scintillator, and these are fixed to a substrate with an insulating adhesive, using a scintillator wafer as the scintillator; After patterning at least the transparent electrode, the amorphous semiconductor layer, and the electrode on the wafer and fixing it to the substrate with an insulating adhesive, a cut is made to a predetermined depth from the scintillator wafer side, and the scintillator, A method for manufacturing a radiation detector, which comprises cutting a transparent electrode, an amorphous semiconductor layer, and an electrode into a predetermined size, and inserting a shielding plate for shielding light or radiation into the cut.