JP2009076726A - Wiring board for mounting x-ray detecting element, and x-ray detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray detecting device of high picture quality, where an influence of reflected X rays from a backside of a wiring board for X-ray detecting element mounting is suppressed. <P>SOLUTION: The wiring board for X-ray detecting element mounting includes a base 1 on which a plurality of insulating layers 1 are stacked, a connection pad 2 for flip-chip mounting an X-ray detecting element 5 formed on a top surface of the base 1, a terminal electrode 3 formed on an external surface of the base 1, and internal wiring 4 including a plurality of through conductors 4a disposed below a mounting region 5a and connecting the connection pad 2 to the terminal electrode 3, wherein an interlayer conductor layer 6 having an opening corresponding to the through conductors 4a is formed in a projection region on the top surface of the base 1 to include the mounting region 5a, the plurality of through conductors 4a are connected via an interlayer connecting conductor 8 formed providing insulating regions 6a to 6c in the opening for the interlayer conductor layer 6, and one insulating region 6c does not overlap other insulating regions 6a and 6b in top plane view. The interlayer conductor layer 6 and interlayer connecting conductor 8 block reflected X-rays to suppress an influence thereof. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an X-ray detection element mounting wiring board and an X-ray detection apparatus using the same.

  With recent advances in semiconductor technology, digitalization of X-ray equipment is progressing. Also, with regard to the display, recording and storage of X-ray images, X-ray images are conventionally recorded and stored on film or the like, but real-time image display and image data storage and transfer are facilitated. Yes. As such an X-ray apparatus, for example, a dental X-ray camera is equipped with an X-ray detection element for converting X-rays irradiated from the outside into image information.

  The X-ray detection element is mainly composed of a large number of photodiodes arranged on the upper surface thereof and a scintillator formed thereon, and the X-rays irradiated on the X-ray detection element are converted into fluorescence by the scintillator. This light changes the voltage-current characteristics of each photodiode, and this change is extracted as X-ray image information.

  Such an X-ray detection element is mounted on a wiring board for mounting an X-ray detection element comprising a ceramic substrate such as an aluminum oxide sintered body for mounting the X-ray detection element and a metallized wiring conductor such as tungsten (W). Built in X-ray equipment. However, since the aluminum oxide sintered body constituting the ceramic base has the property of easily transmitting X-rays, when an X-ray detection element is mounted and used as an imaging unit of an X-ray camera, When X-rays are irradiated through the subject through the top surface of the X-ray detection element, X-rays reflected by other members located behind the imaging unit penetrate the ceramic substrate and enter the X-ray detection element from the back side. However, this causes an unnecessary image different from the subject to be superimposed on the X-ray detection element, so that even the unnecessary image is converted as X-ray image information, and as a result, an accurate and clear image of the subject is obtained. There was a problem that it was difficult to obtain.

For this reason, the conventional X-ray detection element mounting wiring board includes, for example, a base 101 having a mounting region 105a for mounting the X-ray detection element 105 at the center of the upper surface thereof, as shown in a sectional view in FIG. The substrate 101 is composed of a plurality of internal wirings 104 led out from the periphery of the mounting region 105a to the lower surface, and a shielding metallized layer 106 for shielding X-rays reflected from the lower surface. The X-ray detection element 105 is mounted on the wiring board for mounting the X-ray detection element, the terminal electrode of the X-ray detection element 105 and the connection pad 102 are electrically connected via the bonding wire 107, and the terminal electrode 103 is connected to the outside. The external connection cable 109 connected to the electrical circuit is connected, and these are hermetically sealed in an airtight container, thereby forming an imaging unit of the X-ray camera. According to this, since the X-ray reflected by the shielding metallization layer 106 can be shielded from entering from the lower surface of the X-ray detection element 105, a clear X-ray image can be obtained ( For example, see Patent Document 1).
Japanese Patent Laid-Open No. 2001-94139

  In order to cope with the high resolution required for X-ray equipment in recent years, the number of terminals of X-ray detection elements has increased and flip-chip mounting has been achieved. The corresponding wiring board for mounting X-ray detection elements is In order to increase the number of connection terminals for connecting to an increasing number of external electric circuits, it is necessary to form the connection terminals in the form of arrays in the vertical and horizontal directions on the entire lower surface of the substrate. In addition to conventional still images, it is also required to increase the amount of information and improve diagnosis accuracy by shooting moving images.

  However, since the conventional X-ray detection element mounting wiring board is formed with the shielding metallized layer 106 only for shielding X-rays under the mounting region 105a of the base 101, the shielding metallized layer 106 is not provided. As a result, the internal wiring 102 must be expanded and formed, the design becomes complicated and the number of layers needs to be increased, making it difficult to reduce the size and thickness, and to increase the wiring length of the internal wiring 104. Therefore, there is a problem that high-speed operation required for moving image shooting with high-resolution X-rays becomes difficult.

  Further, in order to expand the internal wiring 104 without avoiding the shielding metallization layer 106, the through-conductor is formed so that the through-conductor of the internal wiring 104 is insulated from the shielding metallization layer 106 and penetrates the shielding metallization layer 106. An insulating region (gap) may be provided between the shielding metallized layer 106. However, when an insulating region is provided by forming a normal through conductor that penetrates the insulating layer 101 vertically (parallel to the laminating direction of the insulating layer 101), a plurality of upper and lower insulating regions overlap in a top view. In this portion, the shielding metallization layer 106 does not exist from the lower surface to the upper surface of the wiring board for mounting the X-ray detection element, and the reflected X-ray passes through the X-ray detection element and enters the X-ray detection element. was there.

  The present invention has been devised in view of such conventional problems, and an object of the present invention is to provide an X-ray detection element mounting wiring board when X-rays are irradiated through a subject through the upper surface of the X-ray detection element. Even if X-rays are reflected by other members located below the X-rays, the reflected X-rays do not enter the X-ray detection element from the back side, are small and thin, and operate at high resolution and high speed. An object is to provide a possible wiring board for mounting an X-ray detection element and an X-ray detection apparatus using the same.

  A wiring board for mounting an X-ray detection element according to the present invention includes a substrate in which a plurality of insulating layers are laminated, and the X-ray detection element formed in the X-ray detection element mounting region on the upper surface of the substrate is flip-chip mounted. A plurality of connection pads, a plurality of terminal electrodes formed on an outer surface of the base, and a plurality of through conductors formed inside the base and disposed below the mounting region. A wiring board for mounting an X-ray detection element having a plurality of internal wirings connecting a connection pad and the plurality of terminal electrodes, and a plurality of interlayer conductor layers having openings corresponding to the plurality of through conductors, The insulating layer is formed between the insulating layers so that the mounting region is included in the projected region on the upper surface of the base body, and the plurality of through conductors are provided with an insulating region between the interlayer conductor layers in the openings. When it penetrates the interlayer conductor layer In addition, in at least one of the insulating layers in which the interlayer conductor layer is formed, the cross-sectional area of the through conductor formed by providing the insulating region between the interlayer conductor layer in the opening is larger than that of the through conductor. It is connected via an interlayer connection conductor, and at least one of the insulating regions does not overlap with the other insulating regions in a top view.

  In the X-ray detection element mounting wiring board according to the present invention, in the above configuration, the interlayer conductor layer is formed between three or more insulating layers, and the plurality of insulating regions positioned above and below include the base. When viewed obliquely from the lower surface side, it cannot be seen in a straight line.

  The X-ray detection apparatus of the present invention is characterized in that the X-ray detection element is flip-chip mounted on any of the above-described wiring boards for mounting the X-ray detection element.

  According to the wiring board for mounting the X-ray detection element of the present invention, the plurality of interlayer conductor layers having openings corresponding to the plurality of through conductors are arranged so that the mounting area is included in the projection area on the upper surface of the substrate. The plurality of through conductors pass through the interlayer conductor layer by providing an insulating region between the interlayer conductor layer in the opening and in the opening in at least one of the insulating layers in which the interlayer conductor layer is formed. And an interlayer connection conductor that is larger than the cross section of the through conductor, formed by providing an insulating region between the interlayer conductor layers, and at least one insulating region is connected to the other in the top view. Since it does not overlap with the insulating region, there is at least one layer of the interlayer conductor layer or interlayer connection conductor, which is an X-ray shielding metallization layer, from the lower surface to the upper surface of the substrate in the mounting region, so that it enters from the back surface of the wiring board. X Since the internal wiring is not formed avoiding the interlayer conductor layer for shielding X-rays, the number of terminals of the X-ray detection element is increased in order to cope with higher resolution of the X-ray image. Even if the number is increased, the development of the internal wiring is facilitated, and it is not necessary to lengthen the wiring length. Therefore, the X-ray detection element can be operated at high speed with high resolution because it is small and thin.

  According to the wiring board for mounting an X-ray detection element of the present invention, in the above configuration, the interlayer conductor layer is formed between three or more insulating layers, and the plurality of insulating regions positioned above and below are formed on the bottom surface of the substrate. If the X-ray cannot be seen in a straight line when viewed obliquely from the side, even if the X-ray enters diagonally from the back surface of the wiring board through the lowermost insulating region and the insulating region above it, the X-ray that goes straight Does not pass through the insulating region above the lower two insulating regions, and is shielded by the interlayer conductor layer or the interlayer connection conductor, so that it is less susceptible to unnecessary X-rays.

  According to the X-ray detection apparatus of the present invention, since the X-ray detection element is flip-chip mounted on the X-ray detection element mounting wiring board of the present invention, the X-ray detection element mounting wiring board is a small and thin X-ray detection element mounting wiring board. However, since unnecessary reflected X-rays can be sufficiently shielded, it is possible to reduce the size and thickness and to achieve high image quality.

  Next, the X-ray detection element mounting wiring board of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1A is a cross-sectional view showing an example of an embodiment of the substrate for mounting an X-ray detection element of the present invention, and FIG. 1B is an enlarged view of a portion A of FIG. FIG.

  In FIG. 1, 1a to 1e are insulating layers, 1 is a substrate formed by laminating a plurality of insulating layers 1a to 1e, 2 is a connection pad, 3 is a terminal electrode, 4 is an internal wiring, 4a and 4c are through conductors, 4b Is an internal wiring layer, 5 is an X-ray detection element, 5a is a mounting area of the X-ray detection element 5, 6 is an interlayer conductor layer, 6a, 6b and 6c are insulating areas, 7 is a bonding material, and 8 is an interlayer connection conductor. .

  In the example shown in FIG. 1, the X-ray detection element 5 is flip-chip mounted on the plurality of connection pads 2 formed in the mounting region 5 a of the X-ray detection element 5 on the upper surface of the substrate 1 through the bonding material 7. Thus, an X-ray detection apparatus is configured. The internal wiring 4 is composed of a through conductor 4 a provided in the insulating layers 1 a to 1 e in contact with the interlayer conductor layer 6, an internal wiring layer 4 b, and a through conductor 4 c connecting the internal wiring layer 4 b and the terminal electrode 3. Yes. The interlayer conductor layer 6 is insulated from the internal wiring 4 and has a function of shielding X-rays. The interlayer connection conductor 8 is formed between the insulating layers 1 c and 1 d on which the interlayer conductor layer 6 is formed, and connects the through conductors 4 a located above and below and shields X-rays similarly to the interlayer conductor layer 6. It has a function. An insulating layer is further provided on the insulating layer 1a, and an internal wiring layer 4d and a through conductor 4c for connecting the internal wiring layer 4d and the connection pad 2 are provided between the insulating layer and the insulating layer 1a and in the insulating layer. It may be provided.

  The wiring board for mounting an X-ray detection element according to the present invention has an X-ray detection formed in a base 1 in which a plurality of insulating layers 1 a to 1 e are laminated and a mounting region 5 a of an X-ray detection element 5 on the upper surface of the base 1. A plurality of connection pads 2 for flip-chip mounting the element 5, a plurality of terminal electrodes 3 formed on the outer surface of the base 1, and a plurality of terminals formed inside the base 1 and disposed below the mounting region 5a An X-ray detection element mounting wiring board having a plurality of connection pads 2 and a plurality of internal wirings 4 for connecting a plurality of terminal electrodes 3 including through conductors 4a and 4c, corresponding to the plurality of through conductors 4a A plurality of interlayer conductor layers 6 having openings are formed between the insulating layers 1a, 1b, 1b, 1c, 1c, 1d so that the mounting area 5a is included in the projected area on the upper surface of the substrate 1. The through conductor 4a is between the interlayer conductor layer 6 in the opening. Insulating regions 6a and 6b are provided to penetrate the interlayer conductor layer 6, and at least one of the insulating layers 1a, 1b, 1b, 1c, 1c, and 1d formed with the interlayer conductor layer 6 has an interlayer conductor in the opening. The insulating layer 6c is provided between the upper and lower layers 6 and is connected to each other via an interlayer connection conductor 8 larger than the cross section of the through conductor 6a. The at least one insulating region 6c It is characterized by not overlapping with other insulating regions 6a and 6b.

  For this reason, since there is at least one layer of the interlayer conductor layer 6 or the interlayer connection conductor 8 which is an X-ray shielding metallization layer from the lower surface to the upper surface of the substrate 1 in the mounting region 5a, it penetrates from the back surface of the wiring board. Since most of the coming X-rays can be shielded and the internal wiring 4 is not formed avoiding the interlayer conductor layer 6 for shielding the X-rays, the X-ray detection is performed in order to cope with the high resolution of the X-ray image. Even if the number of terminals of the element 5 is increased, the development of the internal wiring 4 is facilitated, and it is not necessary to lengthen the wiring length. Therefore, it is small and thin, and the X-ray detection element 5 can be operated at a higher speed. It becomes a wiring board for mounting an X-ray detection element.

  Here, the mounting region 5a is a projection region of the X-ray detection element 5 onto the upper surface of the substrate 1 in a state where the X-ray detection element 5 is flip-chip mounted on the wiring board for mounting the X-ray detection element. In FIG. 1 (b), the mounting region 5 a has the same shape and dimensions as the outer shape of the X-ray detection element 5 and is indicated by a one-dot chain line. When the light receiving part of the X-ray detection element 5 is smaller than the outer shape of the X-ray detection element 5, it may be a projection region on the upper surface of the base 1 of the light receiving part of the X-ray detection element 5, but unnecessary X-rays In order to reliably shield the X-ray detection element 5, a projection region on the upper surface of the base 1 of the X-ray detection element 5 is preferably used.

  In the example shown in FIG. 1, three interlayer conductor layers 6, 6, 6 having openings between three insulating layers 1 a, 1 b, 1 b, 1 c, 1 c, 1 d are formed. In the openings of the upper two interlayer conductors 6, 6, the through conductor 4 a penetrates the interlayer conductor layer 6 by providing insulating regions 6 a, 6 b with the interlayer conductor layer 6. In the opening of the lowermost interlayer conductor layer 6, an interlayer connection conductor 8 larger than the cross section of the through conductor 4 a is formed by providing an insulating region 6 c between the interlayer conductor layer 6. 4a and 4a are connected. In this example, the opening diameters of the two-layer interlayer conductors 6 and 6 are the same, and the diameter of the interlayer connection conductor 8 and the opening diameter of the lower-layer interlayer conductor 6 are larger than the opening diameters of the upper-layer interlayer conductors 6 and 6. Therefore, the upper two insulating regions 6a and 6b completely overlap each other and do not overlap with the lower insulating region 6c when viewed from above. As a result, the X-rays reflected from the lower surface of the wiring board are surrounded by the one-layer interlayer connection conductor 8 or the upper two-layer interlayer conductor layers 6 and 6 and the interlayer connection conductor 8 in the vicinity of the through conductor 4a as viewed from above. Alternatively, it is shielded by the upper two interlayer conductor layers 6 and 6.

  2, the interlayer connection conductor 8 is formed in all of the insulating layers 1 a, 1 b, 1 b, 1 c, 1 c, 1 d on which the interlayer conductor layer 6 is formed. Is preferred. By providing the interlayer connection conductor 8, the upper and lower penetrating conductors 4 a, even if a displacement occurs between the insulating layers 1 a, 1 b, 1 b, 1 c, 1 c, 1 d when producing the wiring board for mounting the X-ray detection element. 4a can be easily connected to each other, and the small insulating regions 6a, 6b, and 6c can be formed more easily, so that the X-ray shielding effect is higher. In the case where the interlayer connection conductor 8 is not formed, the size of the insulating regions 6a, 6b, 6c between the through conductor 4a and the interlayer conductor layer 6 is set to a size necessary for ensuring insulation, and between the through conductor 4a and the interlayer conductor. In contrast to the case where the interlayer connection conductor 8 is formed, the interlayer connection conductor 8 and the interlayer connection conductor 8 are simultaneously formed by printing a conductor paste. Therefore, it is possible to make only the dimensions necessary to ensure insulation. Further, since the interlayer connection conductor 8 is provided on the through conductor 4a, there is no difference in height between the upper surface of the through conductor 4a and the upper surface of the interlayer conductor layer 6 formed therearound. Thus, when the plurality of insulating layers 1a to 1f are stacked, the difference in height is accumulated and the upper surface of the wiring board is flattened. Therefore, the mounting reliability of the X-ray detection element is also improved.

  Further, as in the example shown in FIG. 2, it is preferable that the insulating regions 6 a, 6 b, 6 c positioned above and below do not overlap each other when viewed from above. By doing so, at least two layers of the interlayer conductor layer 6 and the interlayer connection conductor 8 which are X-ray shielding metallization layers exist from the lower surface to the upper surface of the substrate 1 in the mounting region 5a. The effect of shielding X-rays entering from the back surface is further increased. In the example shown in FIG. 2, the openings provided in the three interlayer conductor layers 6, 6, and 6 and the interlayer connection conductor 8 inside thereof have the same size as those provided in the same interlayer conductor layer 6. The opening of the interlayer conductor layer 6 between the layer 1a and the insulating layer 1b and the size of the interlayer connection conductor 8 are small in diameter, and the interlayer conductor layer 6 between the layers of the insulating layer 1b and the insulating layer 1c (middle layer). The size of the opening and the interlayer connection conductor 8 is medium, and the size of the opening (interlayer connection layer 6) between the insulating layers 1c and 1d and the interlayer connection conductor 8 is large. Yes. Even when one of the three layers of the interlayer connection conductor 8 is not provided, the other two layers of the interlayer connection conductors 8 and 8 are both larger than the opening of the one layer of the interlayer conductor layer 6 and have different sizes. By providing the interlayer connection conductor 8 according to the diameters of the openings, it is possible to prevent the insulating regions 6a, 6b, 6c positioned above and below from overlapping each other when viewed from above.

  The openings in one interlayer conductor layer 6 and the diameters of the interlayer connection conductors 8 inside thereof are not necessarily the same. FIG. 3 is a cross-sectional view similar to FIG. 1. Compared with the example shown in FIG. 2, the upper and lower interlayer conductor layers 6 have large and small diameter openings and interlayer connection conductors 8 alternately arranged vertically and horizontally. In the upper layer and the lower layer, the arrangement of the large diameter and the small diameter in the top view is reversed. By doing in this way, the space | interval between penetration conductor 4a * 4a can be made small, and it can be set as the smaller X-ray detection element mounting wiring board by which the penetration conductor 4a is arrange | positioned at high density.

  In the example shown in FIGS. 2 and 3, the opening of the intermediate and lower interlayer conductor layers 6 and the diameter of the interlayer connection conductor 8 are sequentially increased or decreased in proportion to the distance from the upper interlayer conductor layer 6. With such a size relationship, the plurality of insulating regions 6a, 6b, 6c positioned above and below can be seen in a straight line when the base 1 is viewed obliquely from the lower surface side. As shown, there are a few cases where X-rays enter the insulating regions 6c, 6b, 6a obliquely straight from the back surface of the wiring board.

  Therefore, as shown in FIG. 4, FIG. 5 and FIG. 6 in a sectional view similar to FIG. 1, the X-ray detection element mounting wiring board of the present invention has the interlayer conductor layers 6, 6 in the above configuration. , 6 are formed between three or more insulating layers 1 a, 1 b, 1 b, 1 c, 1 c, 1 d, and a plurality of insulating regions 6 a, 6 b, 6 c positioned vertically It is preferable that the line cannot be seen in a straight line when viewed. Thus, even if X-rays enter obliquely from the back surface of the wiring board through the lower insulating region 6c and the insulating region 6b thereabove, the straight X-rays are transmitted from the lower two insulating regions 6b and 6c. Since it does not pass through the upper insulating region 6a and is shielded by the interlayer conductor layer 6 or the interlayer connection conductor 8, it is less susceptible to unnecessary X-rays.

  The example shown in FIG. 4 is different from the example shown in FIG. 2 in the width of each insulating region 6a, 6b, 6c (interval between the interlayer connection conductor 8 and the interlayer insulation layer 6), the upper interlayer conductor layer 6 and the interlayer connection. The diameter of the conductor 8 and the thickness of the insulating layers 1b and 1c are the same, but the diameter of the intermediate interlayer conductor layer 6 and the interlayer connection conductor 8 is small, and the diameter of the lower interlayer conductor layer 6 and the interlayer connection conductor 8 is large. Is. In this way, as indicated by an arrow X in FIG. 4, even if X-rays enter the diagonally straight line from the back surface of the wiring board through the lowermost insulating region 6c and the insulating region 6b thereabove. , And is shielded by the interlayer connection conductor 8 thereon. In the example shown in FIG. 4, the distance between the openings in each interlayer conductor layer 6 is the same as that in the example shown in FIG. 2, so that the through conductors are increased by increasing the diameters of the lower interlayer conductor layer 6 and the interlayer connection conductor 8. The distance between 4a and 4a is also increased. When it is desired to reduce the distance between the through conductors 4a and 4a to reduce the size of the wiring board for mounting the X-ray detection element, the openings of the upper and lower interlayer conductor layers 6 and the interlayer connection conductors as in the example shown in FIG. What is necessary is just to arrange 8 by mixing a large diameter and a small diameter.

  Further, the example shown in FIG. 5 may be used. That is, the intermediate interlayer conductor layer 6 and the interlayer connection conductor 8 and the lower interlayer conductor layer 6 and the interlayer connection conductor 8 in the example shown in FIG. It is larger than the opening of the upper and lower interlayer conductor layers 6 and the interlayer connection conductor 8. By doing so, as indicated by an arrow X in FIG. 5, even if X-rays incline from the back surface of the wiring board through the lowermost insulating region 6c and the insulating region 6b thereon obliquely and invade. Are shielded by the interlayer conductor layer 6 thereon. The same applies to the case where the upper layer and the lower layer are interchanged. Contrary to the example shown in FIG. 5, the opening of the middle interlayer conductor layer 6 and the interlayer connecting conductor 8 are replaced with the opening of the upper and lower interlayer conductor layers 6 and the interlayer connecting conductor 8. It may be smaller.

  Moreover, you may make it like the example shown in FIG. That is, with respect to the example shown in FIG. 2, the thickness of the insulating layer 1b between the upper interlayer conductor layer 6 and the middle interlayer conductor layer 6 is increased by 1.5 times, so that the middle interlayer conductor layer 6 and the lower interlayer conductor are The thickness of the insulating layer 1c between the layers 6 is 0.5 times. By doing so, as indicated by an arrow X in FIG. 6, even if X-rays enter the diagonally straight line from the back surface of the wiring board through the lowermost insulating region 6 c and the insulating region 6 b thereabove. , And is shielded by the interlayer connection conductor 8 thereon.

  Thus, by adjusting the opening of the interlayer conductor layer 6 and the diameter of the interlayer connection conductor 8, adjusting the thickness of the insulating layer between the interlayer conductor layers 6, or combining these adjustments, the upper layer The opening of the interlayer conductor layer 6 and the diameter of the interlayer connection conductor 8 in the layer below the opening of the interlayer conductor layer 6 and the diameter of the interlayer connection conductor 8 are proportional to the distance from the upper interlayer conductor layer 6. So that it does not become larger or smaller in order.

  When the insulating layer 1 is made of an aluminum oxide sintered body, the substrate 1 is prepared by adding a suitable organic binder / solvent to a raw material powder such as aluminum oxide / silicon oxide / magnesium oxide / calcium oxide and mixing the slurry. This is made into a sheet by a sheet forming method such as a doctor blade method to obtain a plurality of ceramic green sheets. Next, these ceramic green sheets are subjected to appropriate punching processing and laminated vertically. The ceramic green sheet laminate is finally manufactured by firing the ceramic green sheet laminate in a reducing atmosphere at a temperature of about 1600 ° C.

  The connection pad 2, the terminal electrode 3, the internal wiring 4, the interlayer conductor layer 6, and the interlayer connection conductor 8 are formed by simultaneous firing with the base 1, tungsten (W), molybdenum (Mo), copper (Cu), silver It consists of a metallized conductor layer whose main component is a metal powder such as (Ag). In order to form by simultaneous baking, it is preferable that each conductor layer has the same kind of metal powder as a main component. If these are made of, for example, tungsten metallization, they are obtained by adding and mixing an appropriate organic binder / solvent with a tungsten powder having an average particle size of about 1 to 5 μm, and, if necessary, ceramic or glass powder. It can be obtained by printing and applying a metal paste on a ceramic green sheet to be the insulating layer 1 by screen printing or the like, and simultaneously firing the ceramic green sheet. Of the internal wiring 4, the through conductors 4 a and 4 c have through holes formed in advance in the ceramic green sheet by punching with a die or a pin or laser processing before being applied by screen printing or the like. The hole may be filled with a metal paste by a printing method.

  The cross-sectional shape of the through conductors 4a and 4c may be a polygon or an ellipse other than a circle as shown in FIGS. 1 to 5, and the through conductors 4a, 4a, The shape of the cross section of 4c may be the same or different. If a large number of through-holes are formed close to each other, cracks are likely to occur in the ceramic green sheet between the through-holes. Polygons are preferred, and circles and ellipses that do not have corners are more preferred because cracks are less likely to occur and uneven wear of the mold is less likely to occur.

  In order to efficiently manufacture using the same mold, pins or processing conditions when forming the through holes, the through conductors 4a and 4c formed in the same insulating layers 1a, 1b, 1c, 1d and 1e are used. The cross sections are preferably the same shape and the same size.

  For the interlayer conductor layer 6 and the interlayer connection conductor 8, a metal material such as tungsten (W), molybdenum (Mo), copper (Cu), silver (Ag) is preferably used in terms of heat resistance and conductivity. The X-ray shielding effect varies depending on the atomic weight of the metal material used, and the shielding effect is higher as the atomic weight is larger. The atomic weights of tungsten, molybdenum, copper, and silver are about 184, about 96, about 64, and about 108, respectively. For the reflection of X-rays from the back surface, with a tungsten having an atomic weight of about 184, a thickness of 0.05 mm is sufficient to shield the reflection of X-rays from the back surface, but the atomic weight is about 64. In the case of copper, a thickness of about 0.15 mm, which is about three times the thickness, is required, so it is necessary to increase the layer thickness per layer or increase the number of interlayer conductor layers 6. In the case of using glass ceramics for the substrate 1, it is preferable to use silver having a higher X-ray shielding effect than copper for the interlayer conductor layer 6 and the like because the X-ray detection element mounting wiring board can be made thin.

  The thickness per layer of the interlayer conductor layer 6 and the interlayer connection conductor 8 is preferable because the number of layers can be reduced as the thickness is increased, and the wiring board for mounting the X-ray detection element can be made thinner. When the ceramic green sheet is laminated, a gap is formed around the interlayer conductor layer 6 and the interlayer connection conductor 8 and peeled off during firing, or a gap communicating with the outside. As a result, moisture or the like may enter and insulation failure or internal wiring 4 may be corroded. Therefore, the thickness of one layer is preferably about 30 μm. Also, after the conductor paste is printed on the green sheet and dried, press working with a mold is performed to embed the conductor layer in the green sheet, or the same slurry as the slurry for producing the ceramic green sheet around the conductor layer It is better to eliminate the step by printing things. Alternatively, a ceramic green sheet may be formed by applying a slurry on a substrate such as a resin film on which a conductor paste is printed to produce a green sheet in which the conductor layer is buried.

  Since the interlayer conductor layer 6 is for shielding X-rays, it is formed so that the projection area on the upper surface of the substrate 1 corresponds to the mounting area 5a. As in the example shown in FIGS. 1 and 2, the X-ray entering obliquely with respect to the upper surface of the X-ray detection element mounting wiring board is shielded by forming a solid pattern that is slightly larger than the mounting region 5a. This is preferable. In addition, an opening that is slightly larger than the through conductor 4a and the interlayer connection conductor 8 is provided so as to be insulated from the through conductor 4a. The size of the insulating region between the through conductor 4a or the interlayer connection conductor 8 and the interlayer conductor layer 6 should be as small as possible in order to shield X-rays, so that the opening crosses the through conductor 4a or the interlayer connection conductor 8. It is preferable that the shape is similar to the surface shape and has an interval of about 50 μm or more from the outer periphery of the through conductor 4a and the interlayer connection conductor 8 in consideration of insulation.

  The shape of the interlayer connection conductor 8 is not particularly limited, but it is preferable to form the interlayer connection conductor 8 in a shape similar to the cross-sectional shape of the through conductor 4a because it can cover the same extent regardless of the direction of displacement.

  Note that the surfaces of the connection pads 2 and the terminal electrodes 3 formed on the outer surface of the substrate 1 prevent oxidation corrosion, and join the connection pads 2 and the electrodes of the X-ray detection element 5 and the terminal electrodes 3 and external circuits. Electrolytic plating with nickel plating with a thickness of about 1 to 10 μm and gold plating with a thickness of about 0.1 μm to 3 μm, with excellent wettability with the bonding material 7 such as solder, etc. It may be applied sequentially by a method or an electroless plating method.

  The X-ray detection apparatus of the present invention is characterized in that the X-ray detection element 5 is flip-chip mounted on the wiring board for mounting the X-ray detection element as described above. For this reason, even a small and thin wiring board for mounting an X-ray detection element can sufficiently shield the reflected unnecessary X-rays, resulting in a high-quality X-ray detection apparatus that can be reduced in size and thickness.

  In order to flip-chip mount the X-ray detection element 5 on the mounting region 5a, bonding to the electrode pad 2 is performed by a known method, for example, bonding using a bonding material 7 such as solder or conductive resin, or the X-ray detection element 5 What is necessary is just to carry out by ultrasonic bonding using the gold bump electrode formed in this.

  In addition, when the X-ray detection element mounting wiring board and the X-ray detection element 5 are formed in the same size, the X-ray detection elements 5 are two-dimensionally spaced by arranging the X-ray detection devices vertically and horizontally. Therefore, it is possible to perform high-resolution detection without being limited by the resolution of one X-ray detection element 5.

(A) is sectional drawing which shows an example of embodiment of the wiring board for X-ray detection element mounting of this invention, (b) is sectional drawing which looked at the A section in (a) from the top. (A) is sectional drawing which shows an example of embodiment of the wiring board for X-ray detection element mounting of this invention, (b) is sectional drawing which looked at the A section in (a) from the top. (A) is sectional drawing which shows an example of embodiment of the wiring board for X-ray detection element mounting of this invention, (b) is sectional drawing which looked at the A section in (a) from the top. (A) is sectional drawing which shows an example of embodiment of the wiring board for X-ray detection element mounting of this invention, (b) is sectional drawing which looked at the A section in (a) from the top. (A) is sectional drawing which shows an example of embodiment of the wiring board for X-ray detection element mounting of this invention, (b) is sectional drawing which looked at the A section in (a) from the top. (A) is sectional drawing which shows an example of embodiment of the wiring board for X-ray detection element mounting of this invention, (b) is sectional drawing which looked at the A section in (a) from the top. It is sectional drawing which shows an example of embodiment of the conventional wiring board for X-ray detection element mounting.

Explanation of symbols

1: Insulating layer 1a: Substrate 2: Connection pad 3: Terminal electrode 4: Internal wiring 4a: Through conductor 5: X-ray detection element 5a: Mounting area 6: Interlayer conductor layer 6a: Opening 7: Bonding material 8: Interlayer connection conductor

Claims (3)

A base body in which a plurality of insulating layers are stacked, a plurality of connection pads for flip-chip mounting the X-ray detection element formed in the X-ray detection element mounting region on the upper surface of the base body, and an outer surface of the base body A plurality of terminal electrodes formed in the substrate and a plurality of through conductors formed inside the base and disposed below the mounting region, the plurality of connection pads and the plurality of terminal electrodes being connected to each other A plurality of interlayer conductor layers having openings corresponding to the plurality of through conductors in the projection area on the upper surface of the base body. The plurality of through conductors pass through the interlayer conductor layer by providing an insulating region between the plurality of through conductors and the interlayer conductor layer in the opening. Formed said In at least one of the edge layers, the insulating region is provided between the interlayer conductor layers in the opening and is connected via an interlayer connection conductor larger than the cross section of the through conductor. The X-ray detecting element mounting wiring board, wherein at least one of the insulating regions does not overlap with the other insulating regions when viewed from above. The interlayer conductor layer is formed between three or more insulating layers, and the plurality of insulating regions positioned above and below cannot be seen in a straight line when the base is viewed obliquely from the lower surface side. The wiring board for mounting an X-ray detection element according to claim 1. An X-ray detection apparatus, wherein the X-ray detection element is flip-chip mounted on the wiring board for mounting the X-ray detection element according to claim 1.

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