JP2008211159A - Wiring board and electronic apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve long-term reliability by preventing an insulating substrate 2 from being cracked in a wiring board 1 fixed to a mounting substrate 6 by a screw 5. <P>SOLUTION: The present invention relates to a wiring board 1 comprising: an insulating substrate 2 including a first surface 2A at a side where an electronic component is mounted, a second surface 2B at a side opposed to a mounting substrate 6 and a through-hole 2a for passing through a screw; a first sheet metal 3 provided on the first surface 2A of the insulating substrate 2 and including a through-hole 3a corresponding to the through-hole 2a of the insulating substrate 2; and a second sheet metal 4 provided on the second surface 2B of the insulating substrate 2 and including a through-hole 4a corresponding to the through-hole 2a of the insulating substrate 2 and being smaller than the through-hole 2a of the insulating substrate 2. The wiring board can be fixed by suppressing a peripheral part of the through-hole 4a of the second sheet metal 4 by the screw 5, such that the insulating substrate 2 can be suppressed from being cracked by thermal stress caused by a fastening power when fixing the wiring board 1 to the mounting substrate 6 by the screw 5 or a temperature cycle load in a case where the electronic component is mounted and the wiring board is used while being fixed to the mounting substrate 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wiring board and an electronic device using the wiring board.

  Currently, a wiring board on which a semiconductor element such as a transistor, an LSI (Large Scale Integrated circuit) for a CPU (Central Processing Unit), or an IGBT (Insulated Gate Bipolar Transistor) is mounted is directly mounted on a mounting board such as a heat sink or through a common plate. Bonded electronic devices are often used as power modules. Such a semiconductor element can pass a large current, but the generated heat may deteriorate the semiconductor element. For this reason, a ceramic insulating substrate made of aluminum nitride, silicon nitride or the like having excellent electrical insulation and thermal conductivity is used as a wiring board for mounting a semiconductor element, and a ceramic plate in which a metal plate such as copper or aluminum is bonded to both sides thereof. A wiring board is used.

In the conventional electronic device, the wiring board and the mounting board are joined by joining the metal plate located on the back surface of the wiring board and the mounting board with a brazing material. Recently, the reliability of the joining has been further increased. In order to increase the thickness, a method of forming a through hole in the wiring board and fixing with a screw using the through hole is also used (see, for example, Patent Documents 1 and 2).
JP 2003-197824 A JP 2006-186050 A

  However, in the conventional configuration, the semiconductor element when the power module is operated by applying a tightening force to the insulating substrate when the wiring substrate is fixed to the mounting substrate with a screw or after being fixed to the mounting substrate. After being subjected to a temperature cycle load due to heat generation, there was a problem that cracks occurred in the insulating substrate. If a crack occurs in an insulating substrate, the wiring substrate cannot be fixed in close contact with a mounting substrate such as a heat sink, so heat dissipation is reduced, causing malfunction or destruction of the semiconductor element, or upper and lower metal plates. There was a problem that the insulation between them would be lowered and the reliability would be lowered.

  The present invention has been completed in view of the above problems, and its purpose is to prevent the occurrence of cracks in the insulating substrate of the wiring substrate that is fixed to the mounting substrate with screws, thereby improving long-term reliability. And providing an electronic device using the same.

  A first wiring board according to the present invention includes a first surface on which an electronic component is mounted, a second surface on the side facing the mounting substrate, and an insulating substrate having a through hole for passing a screw, and the insulation A first metal plate provided on the first surface of the substrate and having a through hole corresponding to the through hole of the insulating substrate; and provided on the second surface of the insulating substrate; And a second metal plate having a through hole smaller than the through hole of the insulating substrate corresponding to the through hole.

  Further, the second wiring board of the present invention includes an insulating substrate having a first surface on which an electronic component is mounted, a second surface on the side facing the mounting substrate, and a through hole for passing a screw; A first metal plate provided on the first surface of the insulating substrate and having a through hole smaller than the through hole of the insulating substrate corresponding to the through hole of the insulating substrate; and the second metal plate of the insulating substrate. And a second metal plate having a through hole corresponding to the through hole of the insulating substrate.

  The third wiring board of the present invention includes an insulating substrate having a first surface on which an electronic component is mounted, a second surface on the side facing the mounting substrate, and a through hole for passing a screw; A first metal plate provided on the first surface of the insulating substrate and having a through hole smaller than the through hole of the insulating substrate corresponding to the through hole of the insulating substrate; and the second metal plate of the insulating substrate. And a second metal plate having a through hole smaller than the through hole of the first metal plate corresponding to the through hole of the insulating substrate.

  The electronic device according to the present invention includes the electronic component mounted on the first surface side of any one of the first to third wiring boards of the present invention, and is passed through the through hole of the insulating substrate. Further, the first metal plate or the second metal plate is pressed by the head portion of the screw and fixed to the mounting substrate.

  In the electronic device of the present invention, the electronic component is mounted on the first surface side of the third wiring board of the present invention, and is passed through the through hole of the insulating substrate. The first metal plate and the second metal plate are pressed and fixed to the mounting board with a screw having a first screw head that holds the metal plate and a second screw head that holds the second metal plate. It is characterized by that.

  In the electronic device of the present invention, the electronic component is mounted on the first surface side of the third wiring board of the present invention, and the first metal is passed through the through hole of the insulating substrate. A screw having a screw head for pressing the plate and a ring through which the screw is passed to press the second metal plate, and the first metal plate and the second metal plate are pressed and fixed to the mounting substrate. It is a feature.

  According to the first wiring board of the present invention, the first wiring board is provided on the second surface of the insulating substrate facing the mounting board, and has a through hole smaller than the through hole of the insulating board corresponding to the through hole of the insulating board. When the wiring board is fixed to the mounting board with a screw, the screw is passed through the through hole of the insulating board and the periphery of the through hole of the second metal plate is held by the head of the screw. Can be fixed without applying a force to tighten the screw to the insulating substrate. Therefore, the insulating substrate is cracked by the tightening force when fixing the wiring board to the mounting board with screws, or by the thermal stress due to the temperature cycle load when using electronic components such as semiconductor elements mounted on the mounting board. Can be prevented from occurring.

  According to the second wiring board of the present invention, the through-hole is provided on the first surface of the insulating substrate on the side where the electronic component is mounted and is smaller than the through-hole of the insulating substrate corresponding to the through-hole of the insulating substrate. When the wiring board is fixed to the mounting substrate with a screw, the screw is passed through the through hole of the insulating substrate and the periphery of the through hole of the first metal plate at the head of the screw. Since the portion can be pressed and fixed, the force for tightening the screw applied to the insulating substrate can be reduced by the deformation of the first metal plate. Therefore, the insulating substrate is cracked by the tightening force when fixing the wiring board to the mounting board with screws, or by the thermal stress due to the temperature cycle load when using electronic components such as semiconductor elements mounted on the mounting board. Can be prevented from occurring.

  According to the third wiring board of the present invention, the through hole is provided on the first surface of the insulating substrate on the side where the electronic component is mounted and is smaller than the through hole of the insulating substrate corresponding to the through hole of the insulating substrate. A first metal plate having a through hole smaller than the through hole of the first metal plate corresponding to the through hole of the insulating substrate provided on the second surface of the insulating substrate facing the mounting substrate. When the wiring board is fixed to the mounting board with a screw, the screw is passed through the through-hole of the insulating board and the periphery of the through-hole of the first metal plate with the head of the screw or the like. And the peripheral portion of the through hole of the second metal plate can be pressed and fixed, so that the force for tightening the screw applied to the insulating substrate is reduced by the deformation of the first metal plate, and the insulating substrate 2 Wiring board 1 by pressing the second metal plate without applying force to It can be fixed. Therefore, the insulating substrate is cracked by the tightening force when fixing the wiring board to the mounting board with screws, or by the thermal stress due to the temperature cycle load when using electronic components such as semiconductor elements mounted on the mounting board. Can be prevented from occurring.

  According to the electronic device of the present invention, the electronic component is mounted on the first surface side of any one of the first to third wiring boards of the present invention, and the screw passed through the through hole of the insulating substrate. Since the first metal plate or the second metal plate is pressed and fixed to the mounting substrate by the head, the force for tightening the screw applied to the insulating substrate is reduced by the deformation of the first or second metal plate. Then, the wiring board is fixed to the mounting board, so the tightening force when fixing the wiring board to the mounting board with screws, or the temperature when the electronic parts such as semiconductor elements are mounted and fixed to the mounting board The occurrence of cracks in the insulating substrate due to thermal stress due to the cycle load is suppressed, and a highly reliable electronic device is obtained.

  According to the electronic device of the present invention, the electronic component is mounted on the first surface side of the third wiring board of the present invention, and the first metal plate passed through the through hole of the insulating substrate is provided. Since the first metal plate and the second metal plate are pressed and fixed to the mounting substrate with a screw having the first screw head to be pressed and the second screw head to be pressed to hold the second metal plate, the insulating substrate The tightening force when fixing the wiring board to the mounting board with screws is reduced because the tightening force of the screw applied to the wire is reduced and both the first metal plate and the second metal plate are pressed and securely fixed to the mounting board. In addition, it is possible to suppress the generation of cracks in the insulating substrate due to the thermal stress caused by the temperature cycle load when the electronic component such as the semiconductor element is mounted and fixed to the mounting substrate, and the electronic device is highly reliable. .

  According to the electronic device of the present invention, the electronic component is mounted on the first surface side of the third wiring board of the present invention, and the first metal plate passed through the through hole of the insulating substrate is provided. A screw having a screw head to be pressed and a ring through which the screw is passed to press the second metal plate, and the first metal plate by the screw head and the second metal plate by the ring are fixed to the mounting substrate. Therefore, it is possible to reduce the tightening force of the screw that is more easily applied to the insulating substrate by using a screw having a general shape and press both the first metal plate and the second metal plate to be securely fixed. The insulation substrate may crack due to the tightening force when fixing it to the mounting board with screws or the thermal stress due to the temperature cycle load when using electronic components such as semiconductor elements mounted on the mounting board. Is suppressed, and a highly reliable electronic device is obtained.

  The wiring board of the present invention will be described with reference to the drawings. 1 to 4 are cross-sectional views showing an example of an embodiment of a wiring board according to the present invention, and (b) is an enlarged cross-sectional view of a main part showing an enlarged portion A of the wiring board shown in (a). is there. In these drawings, 1 is a wiring substrate, 2 is an insulating substrate, 3 is a first metal plate, 4 is a second metal plate, 5 is a screw, 6 is a mounting substrate, and 7 is a ring. Each cross-sectional view shows a wiring board 1 in which a first metal plate 3 and a second metal plate 4 are provided on the first surface 2A and the second surface 2B of the insulating substrate 2, respectively, and through holes of the insulating substrate 2. The state which was fixed to the mounting board | substrate 6 with the screw 5 which passed 2a is shown.

  As shown in FIG. 1, the first wiring board 1 of the present invention passes the first surface 2 </ b> A on the side where electronic components are mounted, the second surface 2 </ b> B on the side facing the mounting substrate 6, and the screws 5. An insulating substrate 2 having a through-hole 2a, and a first metal plate 3 provided on the first surface 2A of the insulating substrate 2 and having a through-hole 3a corresponding to the through-hole 2a of the insulating substrate 2; And a second metal plate 4 provided on the second surface 2B of the substrate 2 and having a through hole 4a smaller than the through hole 2a of the insulating substrate 2 corresponding to the through hole 2a of the insulating substrate 2. Is.

  According to the first wiring board 1 of the present invention, the penetration of the insulating substrate 2 corresponding to the through hole 2a of the insulating substrate 2 provided on the second surface 2B of the insulating substrate 2 on the side facing the mounting substrate 6. Since the second metal plate 4 having the through hole 4a smaller than the hole 2a is provided, when the wiring substrate 1 is fixed to the mounting substrate 6 with the screw 5, the screw 5 is attached to the insulating substrate 2 as shown in FIG. Since the peripheral portion of the through hole 4a of the second metal plate 4 can be pressed and fixed through the through hole 2a with the seating surface of the head of the screw 5, the force for tightening the screw 5 to the insulating substrate 2 is applied. It can be fixed without. Therefore, due to the tightening force when the wiring substrate 1 is fixed to the mounting substrate 6 with the screw 5 and the thermal stress due to the temperature cycle load when the electronic component such as a semiconductor element is mounted and fixed to the mounting substrate 6, Generation of cracks in the insulating substrate 1 can be suppressed.

  In the first wiring board 1 of the present invention, the through hole 2a of the insulating substrate 2 has a diameter larger than the diameter of the head of the screw 5, for example, so that the head of the screw 5 used for fixing enters. Further, the through-hole 4a of the second metal plate 4 is smaller than the diameter of the head of the screw 5, for example, so that the screw 5 can be passed through and the second metal plate 4 can be pressed by the head of the screw 5. It has a larger diameter than the threaded portion. The through hole 3a of the first metal plate 3 may have any diameter larger than the diameter of the head of the screw 5, for example, so that the head of the screw 5 used for fixing enters. It may be smaller, the same or larger than the diameter of 2a. Since there are microcracks generated when the through-hole 2a is formed around the through-hole 2a of the insulating substrate 2 and the crack may be easily generated, the first metal plate 3 is formed on the insulating substrate 2. In order to prevent thermal stress generated between them from being applied to the periphery of the through-hole 2a of the insulating substrate 2, as shown in FIG. 1B, the first metal plate It is preferable that the through-hole 3a has a diameter larger than the diameter of the through-hole 2a of the insulating substrate 2 so that 3 (joint thereof) is disposed outside the outer periphery of the through-hole 2a of the insulating substrate 2. When the size of the through hole 3a of the first metal plate 3 is the same as or smaller than the size of the through hole 2a of the insulating substrate 2, the position of the junction between the first metal plate 3 and the insulating substrate 2, that is, the activity The position of the metal brazing material or metallization may be provided outside the outer periphery of the through hole 2a of the insulating substrate 2. Similarly, as shown in FIG. 1B, it is preferable that the position of the joint portion with the second metal plate 4 is also provided outside the outer periphery of the through hole 2 a of the insulating substrate 2. Since the microcracks around the through hole 2a are usually about 50 μm or less, when the joint is provided outside the outer periphery of the through hole 2a of the insulating substrate 2 in this way, the outer periphery of the through hole 2a of the insulating substrate 2 is It is preferable that it is provided on the outside of 50 μm or more, more preferably on the outside of 100 μm or more.

  Further, as shown in FIG. 2, the second wiring board 1 of the present invention has a first surface 2 </ b> A on the side where electronic components are mounted, a second surface 2 </ b> B on the side facing the mounting substrate 6, and screws 5. An insulating substrate 2 having a through hole 2a for passing through, and a through hole 3a which is provided on the first surface 2A of the insulating substrate 2 and which is smaller than the through hole 2a of the insulating substrate 2 corresponding to the through hole 2a of the insulating substrate 2 And a second metal plate 4 provided on the second surface 2B of the insulating substrate 2 and having a through hole 4a corresponding to the through hole 2a of the insulating substrate 2. It is what.

  According to the second wiring board 1 of the present invention, the through-hole of the insulating substrate 2 corresponding to the through-hole 2a of the insulating substrate 2 provided on the first surface 2A on the side on which the electronic component of the insulating substrate 2 is mounted. Since the first metal plate 3 having the through hole 3a smaller than the hole 2a is provided, when the wiring substrate 1 is fixed to the mounting substrate 6 with the screw 5, the screw 5 is attached to the insulating substrate 2 as shown in FIG. Since the periphery of the through hole 3a of the first metal plate 3 can be pressed and fixed through the through hole 2a with the head of the screw 5, the force applied to the insulating substrate 2 and tightening the screw 5 is the first. This can be reduced by the deformation of the metal plate 3. Therefore, due to the tightening force when the wiring substrate 1 is fixed to the mounting substrate 6 with the screw 5 and the thermal stress due to the temperature cycle load when the electronic component such as a semiconductor element is mounted and fixed to the mounting substrate 6, Generation of cracks in the insulating substrate 2 can be suppressed. Thereby, the electronic component mounted on the wiring board 1 can be operated normally and stably.

  In the second wiring board 1 of the present invention, the through-hole 2a of the insulating substrate 2 is, for example, the head of the screw 5 so that the first metal plate 3 can be deformed so as to reduce the force of tightening the screw 5. It has a diameter larger than the diameter of the part. Further, the through-hole 3a of the first metal plate 3 has, for example, a diameter larger than the diameter of the head of the screw 5 so that the screw 5 can be passed and the first metal plate 3 can be pressed by the head of the screw 5. It is smaller and larger than the diameter of the screw portion of the screw 5 and smaller than the diameter of the through hole 2 a of the insulating substrate 2. The through hole 4a of the second metal plate 4 may have any diameter larger than the diameter of the head of the screw 5, for example, so that the head of the screw 5 used for fixing enters. It may be smaller, the same or larger than the diameter of 2a.

  For the same reason as the first metal plate 3 of the first wiring board 1 of the present invention described above, the second metal plate 4 (joining part thereof) is arranged outside the outer periphery of the through hole 2a of the insulating substrate 2. Thus, it is preferable to make the through hole 4 a larger than the diameter of the through hole 2 a of the insulating substrate 2. Similarly, when the size of the through hole 4a of the second metal plate 4 is the same as or smaller than that of the through hole 2a of the insulating substrate 2, the joint between the second metal plate 4 and the insulating substrate 2 is used. That is, the position of the active metal brazing material or metallization may be provided outside the outer periphery of the through hole 2a of the insulating substrate 2. Further, as shown in FIG. 2B, it is preferable that the position of the joint portion with the first metal plate 3 is also provided outside the outer periphery of the through hole 2 a of the insulating substrate 2. In this case, not only when the first metal plate 3 is joined to the insulating substrate 2 but also when the screw 5 is tightened to fix the wiring substrate 1 to the mounting substrate 6, the outer periphery of the through hole 2 a of the insulating substrate 2. Tightening force can be made difficult to be applied to the part. Thus, when providing a junction part outside the outer periphery of the through-hole 2a of the insulating substrate 2, for the same reason as described above, the outer periphery of the through-hole 2a of the insulating substrate 2 is more than 50 μm outside, more preferably more than 100 μm outside. It is preferable to provide in.

  Further, as shown in FIG. 3 or FIG. 4, the third wiring board 1 of the present invention includes a first surface 2 </ b> A on the side where electronic components are mounted and a second surface 2 </ b> B on the side facing the mounting substrate 6. And an insulating substrate 2 having a through-hole 2a through which the screw 5 is passed, and a smaller one than the through-hole 2a of the insulating substrate 2 provided on the first surface 2A of the insulating substrate 2 and corresponding to the through-hole 2A of the insulating substrate 2 A first metal plate 3 having a through hole 3a and a through hole smaller than the through hole 3a of the first metal plate 3 provided on the second surface 2B of the insulating substrate 2 and corresponding to the through hole 2a of the insulating substrate 2 And a second metal plate 4 having 4a.

  According to the third wiring board of the present invention, the through hole 2a of the insulating substrate 2 is provided on the first surface 2A on the side where the electronic component of the insulating substrate 2 is mounted and corresponds to the through hole 2a of the insulating substrate 2. A first metal plate 3 having a smaller through-hole 3a and a first hole corresponding to the through-hole 2a of the insulating substrate 2 provided on the second surface 2B of the insulating substrate 2 on the side facing the mounting substrate 6 3 or 4 when the wiring board 1 is fixed to the mounting board 6 with the screws 5, since the second metal board 4 having a through hole 4a smaller than the through hole 3a of the metal plate 3 is provided. Further, the screw 5 is passed through the through hole 2a of the insulating substrate 2 and the periphery of the through hole 3a of the first metal plate 3 is pressed by the head of the screw 5 and the periphery of the through hole 4a of the second metal plate 4 Since the portion can be pressed and fixed, the force for tightening the screw applied to the insulating substrate 2 is the first Together is the genus plate 3 reduces by deforming, it can be fixed to the wiring board 1 by pressing the second metal plate without applying a force to the insulating substrate 2. Therefore, due to the tightening force when the wiring substrate 1 is fixed to the mounting substrate 6 with the screw 5 and the thermal stress due to the temperature cycle load when the electronic component such as a semiconductor element is mounted and fixed to the mounting substrate 6, Generation of cracks in the insulating substrate 2 can be suppressed.

  In order to fix the third wiring board 1 of the present invention to the mounting board 6, a normal head (first head) that presses the peripheral part of the through hole 3 a of the first metal plate 3 as shown in FIG. Part) and a second head having a middle thickness between the first head and the threaded portion that presses the periphery of the through hole 4a of the second metal plate 4 As shown in FIG. 4, the screw 7 having a head is fixed to the ring 7 that holds the periphery of the through hole 4 a of the second metal plate 4, and the through hole 3 a of the first metal plate 3 is What is necessary is just to fix through the screw 5 which has the normal 1 step | paragraph head (1st head) which presses a periphery part.

  In the third wiring substrate 1 of the present invention, the first metal plate 3 is deformed so that the through-hole 2a of the insulating substrate 2 reduces the force of tightening the screw 5 in the same manner as the second wiring substrate 1. For example, it has a diameter larger than the diameter of the first head of the screw 5. Further, similarly to the second wiring board 1, the through hole 3a of the first metal plate 3 also allows the screw 5 to pass and the first metal plate 3 to be pressed by the first head of the screw 5, for example. The diameter is smaller than the diameter of the first head of the screw 5 and larger than the diameter of the second head of the screw 5 or the ring 7 and smaller than the diameter of the through hole 2 a of the insulating substrate 2. The through hole 4 a of the second metal plate 4 allows the threaded portion of the screw 5 to pass through and holds the second metal plate 4 with the second head or ring 7 of the screw 5, as in the first wiring board 1. For example, the diameter of the second head of the screw 5 or the diameter of the ring 7 is smaller than that of the screw portion of the screw 5.

  Further, as shown in FIG. 3B, the positions of the joint between the insulating substrate 2 and the first metal plate 3 and the joint between the insulating substrate 2 and the second metal plate 4 are the same as described above. Thus, it is preferable that the insulating substrate 2 is provided outside the outer periphery of the through hole 2a. In this case as well, when the joining portion is provided outside the outer periphery of the through hole 2a of the insulating substrate 2, it is preferable to provide the outer periphery of the through hole 2a of the insulating substrate 2 by 50 μm or more, more preferably by 100 μm or more. .

  The electronic device according to the present invention has electronic components mounted on the first surface 2A side of any one of the first to third wiring boards 1 according to the present invention, and is passed through the through hole 2a of the insulating substrate 2. The first metal plate 3 or the second metal plate 4 is pressed by the head of the screw 5 and fixed to the mounting substrate 6. Since such a configuration is adopted, the force for tightening the screw 5 applied to the insulating substrate 2 is reduced by the first metal plate 3 or the second metal plate 4 so that the wiring substrate 1 is fixed to the mounting substrate 6. The insulating substrate 1 is caused by a tightening force when the substrate 1 is fixed to the mounting substrate 6 with the screws 5 or thermal stress due to a temperature cycle load when an electronic component such as a semiconductor element is mounted and fixed to the mounting substrate 6. The occurrence of cracks is suppressed and a highly reliable electronic device is obtained.

  The electronic device according to the present invention includes a first metal that has an electronic component mounted on the first surface 2A side of the third wiring substrate 1 according to the present invention, and is passed through the through hole 2a of the insulating substrate 2. The mounting substrate 6 holds the first metal plate 3 and the second metal plate 4 with a screw 5 having a first screw head for pressing the plate 3 and a second screw head for pressing the second metal plate 4. It is characterized by being fixed to. With such a configuration, the wiring board 1 reduces the tightening force of the screw 5 applied to the insulating substrate 2 and presses both the first metal plate 3 and the second metal plate 4 to ensure the mounting substrate 6. Depending on the tightening force when the wiring board 1 is fixed to the mounting board 6 with the screws 5 and the temperature cycle load when the electronic component such as a semiconductor element is mounted on the mounting board 6 and used. The occurrence of cracks in the insulating substrate 2 due to thermal stress is suppressed, and a highly reliable electronic device is obtained.

  The head of the screw 5 at this time has a first screw head for pressing the first metal plate 3 and a second screw head for pressing the second metal plate 4 as in the example shown in FIG. It becomes a two-stage structure. For example, as shown in FIG. 3, the screw 5 has a first screw head having a diameter larger than that of the through hole 3 a of the first metal plate 3 and smaller than that of the through hole 2 a of the insulating substrate 2. The diameter of the second screw head is smaller than the diameter of the through hole 3 a of the first metal plate 3 and larger than the diameter of the through hole 4 a of the second metal plate 4. The head of the screw 5 has a seating surface that holds the first metal plate 3 of the first head larger than the through hole 3a of the first metal plate 3, and presses the second metal plate 4 of the second head. The seat surface only needs to be larger than the through hole 4a of the second metal plate 4, and the shape from the seat surface of the first head to the seat surface of the second head is the through hole 3a of the first metal plate 3. There is no particular limitation as long as it can be passed. For example, as shown in FIG. 3, the thickness between the seat surface that holds the first metal plate 3 of the first head and the seat surface that holds the second metal plate 4 of the second head is thick. The shape of the second head may be equal to the distance from the seating surface of the first head to the seating surface of the second head, or the same diagram as FIG. The thickness of the second head as in the example shown in FIG. 5 may be small, and the shape between the first head and the second head may be narrower than the two heads.

  When the head of the screw 5 has a two-stage structure, the distance from the seating surface of the first head to the seating surface of the second head (the thickness of the second head in the example shown in FIG. 3) is The surface of the first metal plate 3 that contacts the seating surface of the first head of the screw 5 (the upper surface of the first metal plate 3 in the example shown in FIG. 3) from the insulating substrate 2 side of the second metal plate 4 Active metal brazing material or brazing material located on both surfaces of the surface (the thickness of the first metal plate 3, the thickness of the insulating substrate 2, and the insulating substrate 2) and the surface (the upper surface of the second metal plate 4 in FIG. 3) It is preferable that the thickness is equal to or slightly smaller than the thickness obtained by adding the thickness of the metallized layer. Thereby, both the first metal plate 3 and the second metal plate 4 can be pressed to securely fix the wiring board 1 to the mounting board 6, and the electronic components mounted on the wiring board 1 can be normally and stably. It will be possible to operate.

  Further, the electronic device of the present invention is a first metal plate in which an electronic component is mounted on the first surface 2A side of the third wiring board of the present invention and passed through the through hole 2a of the insulating substrate 2. A screw 5 having a screw head for holding 3 and a ring 7 through which the screw 5 is passed to hold down the second metal plate 4 hold the first metal plate 3 and the second metal plate 4 and are fixed to the mounting substrate 6. It is characterized by that. Since it was set as such a structure, using the screw 5 of a general shape, the clamping force of the screw applied to the insulating substrate 2 can be reduced more easily, and the first metal plate 3 and the second metal plate 4 can be reduced. The clamping force when the wiring board 1 is fixed to the mounting board 6 with the screws 5 and the temperature when the electronic parts such as semiconductor elements are mounted and fixed to the mounting board 6 are used. The occurrence of cracks in the insulating substrate 2 due to the thermal stress due to the cycle load is suppressed, and a highly reliable electronic device is obtained.

  The screw 5 in this case is the same screw 5 that holds down the second wiring board 1 of the present invention, that is, the head larger than the through hole 3a of the first metal plate 3, and the second metal plate 4 penetrating. What has a thread part smaller than the hole 4a should just be used. The outer diameter of the ring 7 is smaller than the through hole 3a of the first metal plate 3 and larger than the through hole 4a of the second metal plate 4, and the inner diameter of the ring 5 is such that the screw 5 passes therethrough. It is larger than the threaded part. The thickness of the ring 7 is such that the surface of the screw 5 of the first metal plate 3 is in contact with the seating surface of the first head (the upper surface of the first metal plate 3 in the example shown in FIG. 3) and the second metal plate 4. The distance to the surface on the insulating substrate 2 side (the upper surface of the second metal plate 4 in the example shown in FIG. 3) (the thickness of the first metal plate 3, the thickness of the insulating substrate 2, and the both surfaces of the insulating substrate 2) The thickness is preferably equal to or slightly smaller than the active metal brazing material or the brazing material plus the thickness of the metallized layer. The ring 7 is made of a metal having higher hardness than the first metal plate 3 and the second metal plate 4, for example, steel or stainless steel when the first metal plate 3 and the second metal plate 4 are made of copper. Steel or the like is desirable because the second metal plate 4 can be reliably pressed by tightening the screws 5. By using the screw 5 and the ring 7 as described above, both the first metal plate 3 and the second metal plate 4 are pressed to securely fix the third wiring board 1 of the present invention to the mounting board 6. Thus, electronic components mounted on the wiring board 1 can be operated normally and stably.

  The insulating substrate 2 has a substantially quadrangular shape and functions as a support member that supports the first metal plate 3 and the second metal plate 4. Such an insulating substrate 2 is made of an electrically insulating material, such as an aluminum oxide sintered body, a mullite sintered body, a silicon carbide sintered body, an aluminum nitride sintered body, or a silicon nitride sintered body. Made of ceramics. Among these, silicon carbide sintered bodies, aluminum nitride sintered bodies, and silicon nitride sintered bodies are preferable from the viewpoint of thermal conductivity (heat dissipation), and silicon nitride sintered bodies are preferable from the viewpoint of strength. preferable. The thinner the thickness, the better in terms of thermal conductivity, but it may be selected according to the size of the wiring board 1 and the thermal conductivity and strength of the material used, and is about 0.3 mm to 3 mm. If the insulating substrate 2 is made of, for example, a silicon nitride sintered body, an appropriate organic binder, plasticizer, and solvent are added to and mixed with raw material powders such as silicon nitride, aluminum oxide, magnesium oxide, and yttrium oxide. The ceramic green sheet (ceramic raw sheet) is formed by applying the doctor blade method and the calender roll method to the sludge, and then the ceramic green sheet is appropriately punched into a predetermined shape. Accordingly, a plurality of sheets are laminated to form a molded body, and thereafter, this is manufactured by firing at a temperature of 1600 to 2000 ° C. in a non-oxidizing atmosphere such as a nitrogen atmosphere.

  The through hole 2a for passing the screw 5 of the insulating substrate 2 is larger than the diameter of the screw head of the screw 5 to be used. The shape in plan view is not particularly limited, and may be a triangle, a quadrangle or a polygon more than that, or a circle or an ellipse. In order to prevent the occurrence of cracks starting from the through hole 2, a shape in which stress is difficult to concentrate is preferable. A hexagonal or more polygonal shape where the angle at which stress tends to concentrate is greater than a right angle is preferred, and more preferably an ellipse or circle with no corners where stress is likely to concentrate, with a constant radius of curvature and stress. A circle with no concentrating parts is optimal.

  The through-hole 2a of the insulating substrate 2 may be formed by forming a through-hole in the ceramic green sheet by punching or laser processing when the insulating substrate 2 is manufactured, and firing the through-hole 2a. After the insulating substrate 2 having no slab is produced, the insulating substrate 2 may be formed by mechanical processing such as laser processing or grinding using a carbon dioxide laser. When the insulating substrate 2 is manufactured by stacking a plurality of ceramic green sheets, the ceramic green sheets having through holes may be aligned and stacked, or a plurality of ceramic green sheets may be stacked. You may form a through-hole which penetrates a molded object. If corners are formed in the longitudinal section of the through-hole 2a due to the stacking position shift, stress is likely to concentrate there, so it is preferable to form the through-holes in the molded body. For the same reason, it is preferable to form the through-hole 2a after the insulating substrate 2 having no through-hole 2a is formed. In this case, the positional displacement of the through-hole 2a in the insulating substrate 2 due to variations in firing shrinkage is also caused. Since there is no, it is more preferable.

  The arrangement (number and position) of the through-holes 2a of the insulating substrate 2 may be set as appropriate depending on the size of the wiring substrate 1, the wiring pattern shape of the first metal plate 3, and the like. Provided at four corners.

  The first metal plate 3 and the second metal plate 4 are made of a metal such as copper or aluminum. For example, a copper ingot (lumb) is chemically processed by mechanical processing such as rolling or punching or etching. By applying a conventionally known metal processing method such as processing, for example, a flat plate having a thickness of 0.05 to 1 mm is formed into a predetermined pattern. At this time, the shape of the first metal plate 3 and the second metal plate 4 may be formed in the shape of the wiring pattern of the wiring board 1, or the first metal plate 3 and the second metal as will be described later. When the plate 4 is bonded to the insulating substrate 2 and then processed into a wiring pattern shape by etching, it may be formed in the same size and shape as the insulating substrate 2.

  FIG. 6A is a plan view showing a main part of an example of the embodiment of the present invention, and FIG. 6B is a cross-sectional view. The through hole 3a of the first metal plate 3 and the through hole 4a of the second metal plate 4 are formed at the same time when the patterns of the first metal plate 3 and the second metal plate 4 are formed. May be one in which the outer periphery of the through hole (shown by a one-dot chain line in FIG. 6) is formed by a plurality of metal plates instead of the through hole provided in one metal plate.

  Further, the first metal plate 3 and the second metal plate 4 are coated by plating with a metal having good conductivity made of nickel and having good corrosion resistance and wettability with the active metal brazing material. In this case, the first metal plate 3 and the second metal plate 4 are electrically connected to the external electric circuit, and an electronic component such as a semiconductor element is soldered to the first metal plate 3. It can be made to adhere firmly through. In this case, if an amorphous alloy of nickel-phosphorus is prepared by containing phosphorus in an amount of 8 to 15% by mass, surface oxidation of the plating layer made of nickel is prevented satisfactorily and wettability with the active metal brazing material is improved. This is preferable because it can be maintained for a long time. If the phosphorus content with respect to nickel is less than 8% by mass or more than 15% by mass, it becomes difficult to form an amorphous alloy of nickel-phosphorous, and the solder cannot be firmly adhered to the plating layer. Cheap. When the thickness of the plating layer made of nickel is less than 1.5 μm, the surfaces of the first metal plate 3 and the second metal plate 4 cannot be completely covered, and the first metal plate 3 And there is a tendency that the oxidative corrosion of the second metal plate 4 cannot be effectively prevented. If the thickness exceeds 3 μm, particularly when the thickness of the insulating substrate 2 is as thin as 700 μm or less, the internal stress inside the plating layer increases and warping or cracking occurs in the insulating substrate 2. It becomes easy to do.

  When the first metal plate 3 and the second metal plate 4 are made of copper and the joining to the insulating substrate 2 is performed using an active metal brazing material, it is preferable to form this with oxygen-free copper. When oxygen-free copper is attached to the insulating substrate 2 via the active metal brazing material, the wettability with the active metal brazing material is improved without the copper surface being oxidized by oxygen present in the copper, The attachment joining of the first metal plate 3 and the second metal plate 4 to the insulating substrate 2 through the active metal brazing material is strengthened.

  The insulating substrate 2 and the first metal plate 3 and the second metal plate 4 may be bonded directly to the insulating substrate 2 using an active metal brazing material, or a metallized layer may be formed on the insulating substrate 2. It may be formed and bonded using a brazing material, or a so-called DBC (Direct Bond Copper) method in which ceramics and a copper plate are directly bonded may be used.

  When the first metal plate 3 and the second metal plate 4 are made of copper and bonded directly onto the insulating substrate 2 using an active metal brazing material, for example, the first surface 2A and the second surface 2 of the insulating substrate 2 are used. The active metal brazing paste is applied to a predetermined pattern with a thickness of, for example, 30 to 50 μm on each surface 2B using a screen printing method, and the predetermined pattern is formed on the first surface 2A and the second surface 2B. After the active metal brazing paste applied by printing is sandwiched between the first metal plate 3 and the second metal plate 4, respectively, the metal plate is subjected to a vacuum or hydrogen gas atmosphere while applying a load of 5 to 10 kPa. Active metal brazing filler metal is heated in a non-oxidizing atmosphere such as hydrogen / nitrogen gas atmosphere at 780 ° C to 900 ° C for 10 to 120 minutes to change the organic solvent, solvent / dispersant of the metal brazing paste into a gas, and emits it. By melting It is done. The active metal brazing paste is composed of silver and copper powder, silver-copper alloy powder, or a silver brazing material composed of these powders (for example, silver: 72% by mass—copper: 28% by mass), titanium, hafnium. , An active metal brazing powder obtained by adding 2 to 5% by mass of an active metal such as zirconium or a hydride thereof, and an appropriate organic solvent / solvent are added and mixed and kneaded.

  When the first metal plate 3 and the second metal plate 4 are made of aluminum, an aluminum brazing material (for example, aluminum: 88% by mass—silicon: 12% by mass) is used instead of the silver brazing material, and the temperature is about 600 ° C. Heat with.

  When the first metal plate 3 and the second metal plate 4 are made of copper and are joined to the metallized layer formed on the insulating substrate 2 using a brazing material, the metal brazing material is replaced with an active metal brazing material paste. What is necessary is just to carry out similarly using a paste. As the metal brazing paste, the above-mentioned silver brazing material containing no active metal may be used. The metallized layer on the insulating substrate 2 may be formed by printing and applying a metallized paste in a predetermined pattern shape on a ceramic green sheet when the insulating substrate 2 is manufactured, and baking the insulating substrate 2. After the production, the metallized paste may be printed on the insulating substrate 2 in a predetermined pattern shape and baked. The metallized paste is manufactured by adding and mixing a metal powder composed of tungsten (W), molybdenum (Mo), manganese (Mn), or a mixed powder thereof, and an appropriate organic solvent / solvent, and kneading. When the first metal plate 3 and the second metal plate 4 are made of aluminum, an aluminum brazing material (for example, aluminum: 88% by mass—silicon: 12% by mass) is used instead of the silver brazing material, and about Heat at 600 ° C.

  When the first metal plate 3 and the second metal plate 4 made of copper are bonded to the insulating substrate 2 and then processed into a wiring pattern shape by etching, the first metal plate 3 bonded on the insulating substrate 2 and Etching resist ink is applied to the surface of the second metal plate 4 by screen printing or the like to form a resist film by printing and applying it to a wiring pattern shape, and then ferric chloride, cupric chloride solution, etc. The resist film may be removed by immersing in an etching solution or spraying an etching solution to remove portions other than the wiring patterns of the first metal plate 3 and the second metal plate 4.

  An electronic device is obtained by mounting electronic components on the wiring board 1 manufactured as described above and electrically connecting them. Examples of electronic components include transistors, semiconductor elements such as LSI (Large Scale Integrated circuit) for CPU (Central Processing Unit), IGBT (Insulated Gate Bipolar Transistor), and MOS-FET (Metal Oxide Semiconductor-Field Effect Transistor). . The electronic component is fixed on a metal bonding material such as solder or Au—Si alloy or a conductive resin, is mounted on the wiring board 1, and is electrically connected by connection means such as wire bonding.

  The screw 5 for fixing the electronic device of the present invention to a mounting substrate 6 such as a heat sink is not particularly limited as long as it is a screw 5 having a head for pressing the first metal plate 3 and the second metal plate 4. However, in the case of an electronic device using the second wiring board 1 of the present invention, a square bolt, a hexagon bolt, or the like may be used because the head of the screw 5 protrudes on the wiring board 1. In the case of an electronic device using the first or third wiring board 1 of the present invention, it is not necessary to provide a large through hole 2a into which a tool for tightening the screw 5 is inserted. It is preferable to use a screw, a hexagon socket head screw, or the like.

  The wiring board 1 and the electronic device of the present invention are not limited to the above-described embodiments, and can be variously modified without departing from the gist of the present invention. For example, as a form of fixing the wiring board 1 of the present invention to the mounting board 6 with the screws 5, a form as shown in cross-sectional views in FIGS. 7A and 7B is also possible. That is, by fixing the first wiring board 1 of the present invention to the mounting board 6 with the screw 5, the first metal board 3 is smaller than the through hole 2 a of the insulating board 2. May be deformed and brought into contact with the second metal plate 4. In this way, electrical conduction can be easily established between the first metal plate 3 and the second metal plate 4. In order to do this, the thickness of the periphery of the through hole 3a of the first metal plate 3 may be reduced. For example, after processing the first metal plate 3 into a predetermined pattern shape, This is possible by etching the periphery again.

  Moreover, the through-hole 3a of the 1st metal plate 3 is the active metal brazing material or brazing material, and metallization layer which are located in the thickness of the insulating substrate 2, and both surfaces of the insulating substrate 2, for example from the diameter of the through-hole 2a of the insulating substrate 2. The diameter is smaller than the thickness of the thickness plus the thickness. The shape of the through hole 3a of the first metal plate 3 extends radially from the center of the through hole 2a of the insulating substrate 2 such as a cross shape so that the stress applied to the insulating substrate 2 can be reduced more easily. It is good also as a shape. In addition, if the entire first metal plate 3 is thin, not only around the through hole 3a of the first metal plate 3, the hardness of the first metal plate 3 is prevented from becoming hard due to the influence of etching or the like. Therefore, the stress on the insulating substrate 2 can be further reduced.

(A) is sectional drawing which shows an example of embodiment of the wiring board of this invention, (b) is a principal part expanded sectional view of (a). (A) is sectional drawing which shows an example of embodiment of the wiring board of this invention, (b) is a principal part expanded sectional view of (a). (A) is sectional drawing which shows an example of embodiment of the wiring board of this invention, (b) is a principal part expanded sectional view of (a). (A) is sectional drawing which shows an example of embodiment of the wiring board of this invention, (b) is a principal part expanded sectional view of (a). It is a principal part expanded sectional view which shows another example of embodiment of the wiring board of this invention shown in FIG.4 (b). (A) is a top view which shows the principal part of an example of embodiment of the wiring board of this invention, (b) is sectional drawing which cut | disconnected (a) by the AA line. (A) is sectional drawing which shows an example of embodiment of the wiring board of this invention, (b) is a principal part expanded sectional view of (a).

Explanation of symbols

1: Wiring substrate 2: Insulating substrate 2A: First surface 2B: Second surface 2a: Through hole 3: First metal plate 3a: Through hole 4: Second metal plate 4a: Through hole 5: Screw 6 : Mounting board 7: Ring

Claims (6)

An insulating substrate having a first surface on which an electronic component is mounted, a second surface on the side facing the mounting substrate, and a through-hole for passing a screw;
A first metal plate provided on the first surface of the insulating substrate and having a through hole corresponding to the through hole of the insulating substrate;
And a second metal plate provided on the second surface of the insulating substrate and having a through hole smaller than the through hole of the insulating substrate corresponding to the through hole of the insulating substrate. substrate. An insulating substrate having a first surface on which an electronic component is mounted, a second surface on the side facing the mounting substrate, and a through-hole for passing a screw;
A first metal plate provided on the first surface of the insulating substrate and having a through hole smaller than the through hole of the insulating substrate corresponding to the through hole of the insulating substrate;
A wiring board comprising: a second metal plate provided on the second surface of the insulating substrate and having a through hole corresponding to the through hole of the insulating substrate. An insulating substrate having a first surface on which an electronic component is mounted, a second surface on the side facing the mounting substrate, and a through-hole for passing a screw;
A first metal plate provided on the first surface of the insulating substrate and having a through hole smaller than the through hole of the insulating substrate corresponding to the through hole of the insulating substrate;
A second metal plate provided on the second surface of the insulating substrate and having a through hole smaller than the through hole of the first metal plate corresponding to the through hole of the insulating substrate. Wiring board. The electronic component is mounted on the first surface side of the wiring board according to any one of claims 1 to 3, and the first screw head passed through the through hole of the insulating substrate. An electronic device, wherein the metal plate or the second metal plate is pressed and fixed to the mounting substrate. A first screw head for holding the first metal plate, wherein the electronic component is mounted on the first surface side of the wiring board according to claim 3 and passed through the through hole of the insulating substrate. And an electronic device characterized in that the first metal plate and the second metal plate are pressed and fixed to the mounting substrate with a screw having a second screw head for pressing the first metal plate and the second metal plate. . A screw having a screw head for holding the first metal plate, wherein the electronic component is mounted on the first surface side of the wiring board according to claim 3 and passed through a through hole of the insulating substrate. And an electronic device, wherein the first metal plate and the second metal plate are pressed and fixed to the mounting substrate by a ring through which the screw is passed to press the second metal plate.

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