JPS6271883A - Manufacture of multichannel type radiation detector - Google Patents

Abstract

PURPOSE:To manufacture a multichannel detector which is highly stable and has no deterioration in sensitivity by an easy method by working a fixed area which is sensitive to radiation on a conductor substrate with a wire saw and then working the substrate to narrow groove cutting width by a slicing machine. CONSTITUTION:The area 1 of the semiconductor detector which is fixed on the conductive substrate 3, equipped with a counter electrode 2, and sensitive to radiation is cut with piano wires 6 and the wire saw of abrasive grains so that cut crushing is small. Then, the substrate 3 is cut at a high speed with high precision by using the slicing machine to groove cut width B narrower than said groove cut width A, and then a rod radiation detector is formed, and detectors are laminated in contact to form the multichannel radiation detector which is highly stable and has no deterioration in sensitivity by the easy method using a proper saw according to the working.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention focuses on a spatially independent multi-channel radiation detector method.

Conventional technology In the method of forming a spatially independent multi-channel radiation detector, as in Japanese Patent Laid-Open No. 58-93292, after bonding a semiconductor substrate that will become a detector on a fixed plate, a Co2 laser or a Methods of cutting and separating using a YAG laser, an ion milling device, a mechanical cutter, etc. have been proposed. Figure 3 is an example. The detector 1 is fixed on the fixing plate 2, and the processing grooves 4 for separation are formed by the method described above to form a multi-channel radiation detector.

Problems that the invention attempts to solve However, thermal processing methods such as laser processing tend to cause thermal deterioration of the semiconductor sensitive layer for thermally unstable materials, making it impractical for practical use. It is difficult to know the method.

Further, an ion milling method has been proposed, but this method is unlikely to be practical if the separation groove depth of the sensitive layer is 100 μm or more.

Currently, the most common processing technique is a method using a mechanical cutter. In particular, the groove machining method using a wire saw, which can reduce the process-affected layer to 6 μm or less, is the most suitable machining method except for intermediate molds with a large wire diameter. Wire saw is 80
Since this is a method of cutting the sample while polishing it using a pier wire of μm to 200 μm and abrasive grains of a grain size of 1 μm to 10 μm, the width of the cutting groove is larger than the diameter of the pier wire. For this reason, when processing minute sensors with a pitch of 1 m or less, the width of the cutting groove causes a decrease in sensitivity.

It is also conceivable to carry each cut detector individually and layer it in layers, but if the detector size is about 100 μm, it is impossible to arrange them with high precision.

In this way, in the conventional method, since the groove width is wide, when forming a multi-channel radiation detector with a minute element size of 11Il11 or less, the groove width or dead area is As the number of detectors increases, the detection sensitivity decreases significantly. For example, even when the groove width is 100 μm, the sensitivity when five 7/s are arranged per 1+a is reduced by 60% compared to the case where the groove width is ideally zero.

The present invention has been made in view of the above, and an object of the present invention is to provide a multi-channel radiation detector that is highly stable and exhibits little decrease in sensitivity using a simple method.

In order to solve the above-mentioned problem, the present invention uses a wire saw with a small amount of damaged layer to process the area sensitive to radiation. , a high-speed, high-precision cutting machine like a slicing machine.
It is characterized in that it is cut with a width narrower than the groove cutting width of a wire saw, and the cut rod-shaped sensors are laminated and fixed.

Operation According to the method described above, the present invention can maximize the semiconductor area sensitive to radiation and minimize the dimensional error caused by arranging a large number of sensors. Furthermore, since the width of the fixing plate is wider than the width of the semiconductor region, spatial independence of the semiconductors can be ensured even when stacked, allowing extremely simple and highly accurate processing.

Embodiment FIG. 1 shows an embodiment of the multi-channel radiation detector of the present invention. In Fig. 1, 1 is a semiconductor detector sensitive to radiation, 2 is an electrode, and 3 is a conductive substrate to which the semiconductor detector 1 is fixed, and a plurality of these are fixed to form a multi-channel radiation detector. ing. The present embodiment will be described below with reference to FIG.

In FIG. 2(a), the semiconductor detector 1 is a thin flat semiconductor wafer, and counter electrodes 2 are formed on the upper and lower surfaces. The material of the semiconductor detector 1 is Si.
, Go, CdTe, GaAs, Hql, and other radiation-sensitive and highly stable materials are used.

For X-ray detection, materials with large atomic numbers have high sensitivity, and Hg I 2 , Cd Te, etc. absorb 90% or more of 60 KeV X-rays even with a thickness of 1 mm or less.

The counter electrode 2 is made of a material having excellent bondability with an external circuit, such as An, Au, or Pt. As the conductor substrate 3, Cu, Fe
, AJ! metals such as copper, alloys such as copper, Si substrates treated to have low resistance, and various ceramics are used. For fixing the semiconductor detector 1 and the conductive substrate 3, a conductive adhesive, a low melting point metal, or a eutectic alloy such as Au-an is used.

Next, the cutting method will be explained. The semiconductor detector 1 manufactured by the method described above is first processed using a wire saw. A wire saw uses abrasive grains on a moving piano wire to polish only the part of the cut object that comes into contact with the wire.
Since it is cut into one square, the fracture layer at the cut portion can be made extremely small by adjusting the wire, load, etc. Therefore, it is possible to form a stable surface without etching or other treatment of the cut portion. Of course, the present invention is also applicable to objects that undergo special processing. In FIG. 2(b), the wire 6 cuts a groove with a groove cutting width A determined by the wire diameter and the grain size of the abrasive grains. The cutting speed of the wire saw varies depending on the material being cut, so the semiconductor detector 1
The connection point with the conductive substrate 3 is confirmed by monitoring the change in cutting speed. Since the cutting dimensional accuracy of a wire saw is generally about 6 .mu.m.-20 .mu.m, when a large number of detectors are stacked and arranged, the dimensional error due to integration becomes too large. When stacking 100 μm detectors, only a maximum of 20% of the positional difference 7 will occur, and this will result in dimensional deviations during assembly, warping due to uneven flatness, etc., resulting in difficulty in assembly and damage to the detection part. This may result in short circuit or damage. Therefore, in this embodiment, the conductive substrate 3 was cut using a slicing machine using an extremely thin disk blade. The cutting grooves of the slicing machines shown in FIGS. 2(a) and 2(b) generally not only have good dimensional accuracy and flatness of the machined surface, but also allow high-speed cutting. The groove cutting width B in Fig. 2 (b>) is smaller than the wire saw cutting width A.The dimensional accuracy of the groove cutting width B is high, 6 μm.
By making the blade thickness of the slicing machine less than or equal to the wire diameter of the wire saw, it is easy to make the rod-shaped detector as follows: (conductor substrate thickness) > (detection part thickness) Can be processed. In addition, in FIG. 2, 4 indicates a cutting section by a wire saw, and s indicates a cutting section by a slicing machine.

A plurality of rod-shaped detectors thus obtained are stacked as shown in FIG. 2(C), and the conductive substrate 3 is fixed.

Conductive adhesives or low-melting point metals are used for fixing. In this embodiment, only the conductor substrate 3 described above was fixed, but it is also possible to use a separate bottom plate to facilitate the assembly process when fixing the conductor substrate 3. Moreover, when stacking these rod-shaped detectors, by inspecting the semiconductor detector 1, it becomes possible to extract defective parts. Furthermore, if a product is defective in only one part, by aligning the parts during stacking and arranging only the good parts in the same place, it is possible to make a good product after cutting, greatly increasing the yield rate in manufacturing. It can be improved.

The rod-shaped detector blocks stacked in this manner are cut in a direction parallel to the stacking direction. Again, a wire saw is used to cut the detection part.

When a plurality of conductor substrates are not laminated, the conductor substrate portion may be cut using a wire saw. When making a two-dimensional multi-channel detector, the same procedure as described above is used.

Effects of the Invention As described above, according to the present invention, it is possible to easily create multiple channels in a spatially independent and extremely small radiation detector, and to minimize the insensitive portion of the radiation entrance surface. , it is possible to significantly improve sensitivity compared to the conventional method.

Furthermore, since the yield is significantly improved, it is also possible to reduce costs, which is extremely useful from a practical standpoint.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a multi-channel radiation detector according to an embodiment of the present invention, Fig. 2 (a), (b), (c)
3 is a perspective view showing a modified culm of the same multi-channel radiation detector, and FIG. 3 is a perspective view of a conventional multi-channel radiation detector. 1...Semiconductor detector, 2...--electrode, 3...
...Conductor board. Name of agent: Patent attorney Toshi Nakao 2') 1 person / --- Half-N throat A 4 positions M 5 M) L1 ≠ to 2-11 electrode 2 @ I Fig. 2 Figure 3.

Claims (2)

[Claims] (1) A multi-channel radiation detector in which radiation-sensitive semiconductor detectors are arranged in a linear or planar manner, in which the radiation-sensitive semiconductor detectors are fixed on a conductive substrate, resulting in less cutting and shattering. The radiation-sensitive semiconductor detector is cut with a first cutter, and then the conductive substrate is cut with a second cutter having a cutting width that is equal to or narrower than the width of the cutting groove made by the first cutter. . A method for manufacturing a multi-channel radiation detector, characterized in that the respective conductor substrates cut by a second cutter are then closely laminated. (2) The method for manufacturing a multi-channel radiation detector according to claim 1, wherein the first cutter is a wire saw. (2) The method for manufacturing a multi-channel radiation detector according to claim 1, wherein the second cutter is a slicing machine.