JP2012146950A - Wiring substrate, wiring substrate with solder bump, electronic device, and method of manufacturing wiring substrate with solder bump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring substrate suppressing cracks of an insulation substrate and enabling coining of a solder bump, and to provide a wiring substrate with a solder bump, an electronic device, and a method of manufacturing a wiring substrate with a solder bump.SOLUTION: In a wiring substrate 9, a mounting part 1b is provided on an upper face of an insulation substrate 1 formed by laminating insulating layers 1a. A plurality of electrode pads 2 are formed to the mounting part 1b. A through conductor 3 is connected to each of the electrode pads 2. Through conductors 3 in the center part of the mounting part 1b penetrate through more insulating layers 1a compared with those in an outer peripheral part of the mounting part 1b. The insulation substrate 1 has a convex part 1c on the upper face. An upper face of the convex part 1c serves as the mounting part 1b. The electrode pad 2 formed to the mounting part 1b is connected to an electrode of the semiconductor element 10 via a solder bump 5. Since the electrode pads 2 are formed using the upper face of the convex part 1c as the mounting part 1b, cracks of the insulation substrate 1 caused by contact with a device applying pressure on the solder bump 5 bonded to the electrode pad 2 can be suppressed.

Description

  The present invention relates to a wiring board for mounting electronic components including semiconductor elements such as LSI and IC, a wiring board with solder bumps formed by bonding solder bumps to the wiring board, and mounting electronic components on a wiring board with solder bumps. And a method of manufacturing a wiring board with solder bumps.

  In recent years, semiconductor devices such as LSIs and ICs have been required to draw a large number of signal lines per unit area. In order to satisfy this requirement, the functional surface of the semiconductor device is used as a lower surface, and the semiconductor device and the wiring board are arranged. So-called flip chip (F / C) mounting is used in which electrodes are connected by melting or pressure welding of solder. Such F / C mounting wiring boards generally have electrode pads arranged on the upper surface of the insulating substrate so as to face the electrodes of the semiconductor element, and are connected to the external circuit board on the lower surface of the insulating substrate. Have a pad for. Each electrode pad is electrically connected to a conductor layer such as a wiring conductor or a pad formed inside the insulating substrate and a pad via a through conductor formed inside the insulating substrate. The pad is electrically connected to an external electric circuit, and the semiconductor element and the external electric circuit are electrically connected.

  In general, the insulating substrate of the wiring board for F / C mounting is made of a ceramic material or an organic material, and the electrode pad is made of a metal material such as copper or silver. In addition, solder bumps for connection to the electrodes of the semiconductor element are bonded to the surfaces of these electrode pads. Electronic components such as semiconductor elements are mounted on the wiring board with solder bumps. An electrode of a semiconductor element is bonded to an electrode pad via a solder bump, and an electronic device (semiconductor device or the like) is manufactured.

  In a structure in which solder bumps are attached on the electrode pads of the wiring board, the height of the solder bumps may vary due to variations in the amount of solder for the solder bumps or deformation due to heating. If the height of the solder bump varies, there is a possibility that the electrode of the semiconductor element cannot be connected to the corresponding solder bump. Therefore, pressure is applied to the solder bumps welded to a large number of electrode pads all at once from the upper surface through the flat surface of a pressure device (so-called coining device), and the height of the upper surfaces of the plurality of solder bumps is increased. An aligning process (so-called coining) is required.

Japanese Unexamined Patent Publication No. 2000-12587 JP 2003-258416 A JP-A-2005-286166

  However, when this coining process is applied to a large number of solder bumps on the insulating substrate, if the surface (upper surface) of the insulating substrate is not flat, a coining device that applies pressure (actually pressurizes the solder bumps, the lower surface is There is a problem in that the edge of the flat press part) comes into contact with the surface of the insulating substrate, and cracks are generated in the insulating substrate starting from the portion hitting the edge.

In particular, in a wiring board having a plurality of electrode pads on which a semiconductor element is F / C mounted, a large number of through conductors connected to the electrode pads are formed immediately below a mounting portion where the plurality of electrode pads are arranged. Therefore, there is a possibility that the mounting portion is recessed due to shrinkage due to sintering (difference between shrinkage timing and shrinkage amount when the through conductor and the insulating substrate are fired). That is, since the amount of shrinkage due to sintering is larger in the metal material forming the through conductor than the ceramic forming the insulating substrate, the insulating substrate (laminated body of ceramic green sheets) provided with the through conductor is not It shrinks more than the part. For this reason, the mounting portion easily deforms into a concave shape in the insulating substrate after firing.

  In addition, the through conductor penetrates more and more insulating layers (up and down) in the central portion than the outer peripheral portion of the mounting portion (the proportion of the volume occupied by the through conductor in the insulating substrate is large). This is because electrical derivation (so-called development) is performed outside the mounting portion sequentially from the outer peripheral side of the electrode pad arranged in the mounting portion via the wiring conductor outside the mounting portion. For this reason, the concave deformation of the insulating substrate tends to be larger at the central portion of the mounting portion than at the outer peripheral portion, and the mounting portion may also be concave.

  As described above, the height of the upper surface of the insulating substrate tends to be lower in the mounting portion (especially the central portion) than in other portions. Therefore, in the coining process, the portion adjacent to the insulating substrate, particularly the mounting portion of the insulating substrate However, there is a problem that cracks due to contact of the coining device may occur. When a crack occurs in the insulating substrate, for example, the mechanical strength, electrical characteristics (insulating properties, etc.), moisture resistance, appearance, etc. of the insulating substrate are lowered.

  The present invention has been completed in view of such conventional problems, and the purpose thereof is a wiring board capable of suppressing the generation of cracks in an insulating substrate when aligning the heights of a large number of solder bumps by coining, A wiring board with solder bumps in which the height of the solder bumps is uniform and cracks in the insulating substrate are suppressed, a highly reliable electronic device in which an electronic component including a semiconductor element is mounted on the wiring board with solder bumps, and An object of the present invention is to provide a method for manufacturing such a wiring board with solder bumps.

  A wiring board according to one aspect of the present invention has a mounting portion of a semiconductor element on an upper surface of an insulating substrate formed by laminating a plurality of insulating layers, and a plurality of electrodes connected to the electrodes of the semiconductor element on the mounting portion. A wiring board in which a pad is formed and a through conductor penetrating the insulating layer in the thickness direction is connected to each of the electrode pads, and the through conductor is located in a central portion rather than an outer peripheral portion of the mounting portion Penetrates more of the insulating layer, and the insulating substrate has a convex portion on the upper surface, and the upper surface of the convex portion is a mounting portion of the semiconductor element. The formed electrode pad is connected to the electrode of the semiconductor element through a solder bump.

  A wiring board with solder bumps according to one aspect of the present invention includes the wiring board having the above-described configuration and solder bumps bonded to the electrode pads of the wiring board, and the solder bumps are pressed from above to be top surfaces. Are arranged at the same height.

  An electronic device according to an aspect of the present invention includes a wiring board with solder bumps having any one of the above-described structures, and a semiconductor element mounted on the mounting portion of the wiring board with solder bumps and having electrodes connected to the solder bumps It is characterized by providing.

A method of manufacturing a wiring board with solder bumps according to one aspect of the present invention has a mounting portion of a semiconductor element on an upper surface of an insulating substrate formed by laminating a plurality of insulating layers, and the mounting portion is connected to an electrode of the semiconductor element. A plurality of electrode pads are formed, a through conductor that penetrates the insulating layer in the thickness direction is connected to the electrode pad, and the insulating layer penetrates the electrode pad in the thickness direction. A method of manufacturing a wiring board with solder bumps, comprising: a wiring board to which a through conductor is connected; and a solder bump bonded to the electrode pad.
A plurality of ceramic green sheets serving as the insulating layers are prepared, and a region for mounting the semiconductor element is provided in a part of the ceramic green sheet, and the ceramic green sheets are disposed in the thickness direction in the region to be the mounting portion. Forming a through-hole penetrating;
Printing the metal paste to be a plurality of the electrode pads on the main surface of the ceramic green sheet in the mounting portion, and filling the metal paste to be the through conductor in the through hole;
A plurality of the ceramic green sheets are laminated by laminating at least one of a metal paste and a ceramic paste between the upper and lower ceramic green sheets immediately below the region to be the mounting portion, to form a laminate, A step of firing the laminate;
Printing a solder paste on each of the plurality of electrode pads, heating the solder paste, and forming solder bumps on each of the plurality of electrode pads;
And pressurizing the plurality of solder bumps from above to align the heights of the upper surfaces of the plurality of solder bumps.

  According to a wiring board according to one aspect of the present invention, the insulating substrate has the above-described configuration, and the insulating substrate has a convex portion on the upper surface, and the upper surface of the convex portion is a mounting portion of the semiconductor element. Since the electrode pads are formed on the insulating substrate, the height of the upper surface of the insulating substrate is higher in the mounting portion, that is, in the portion where many electrode pads are arranged than in the other portions. Therefore, even if a concave warp occurs on the upper surface of the insulating substrate, the upper surface of the insulating substrate is suppressed from becoming higher than the solder bump on the electrode pad. Therefore, after forming solder bumps on the electrode pads, when aligning the height of the solder bumps using a coining device, the coining device is prevented from coming into contact with the top surface of the insulating substrate other than the mounting portion, and cracks are generated in the insulating substrate. Can be suppressed.

  According to the wiring board with solder bumps according to one aspect of the present invention, the solder bumps are bonded to the wiring board having the above-described configuration, and the solder bumps are pressed from the upper side so that the height of the upper surface is uniform. Therefore, the semiconductor element can be connected and mounted on the solder bump without tilting. Further, as in the case of the wiring board of the present invention, cracks in the insulating substrate are suppressed. Therefore, it is possible to provide a wiring board with solder bumps on which a semiconductor element can be mounted and a highly reliable electronic device can be manufactured.

  According to an electronic device according to one aspect of the present invention, the wiring board with solder bumps having the above-described configuration and a semiconductor element mounted on the mounting portion of the wiring board with solder bumps and having electrodes connected to the solder bumps are provided. Accordingly, since the semiconductor element is connected to the solder bumps having the same height, an electronic device in which the inclination of the semiconductor element is suppressed can be provided. Moreover, since the crack of the insulating substrate is suppressed, the reliability as an electronic device is high.

  In addition, according to the method for manufacturing a wiring board with solder bumps according to one aspect of the present invention, each of the above steps is provided, and a plurality of ceramic green sheets are placed between the upper and lower ceramic green sheets immediately below the region to be the mounting portion. Since a laminated body is formed by laminating at least one of a metal paste and a ceramic paste in a layered manner, a portion where at least one of the metal paste and the ceramic paste (paste layer) is interposed in the laminated body serving as an insulating substrate In this case, a convex portion can be formed on the upper surface in the region to be the mounting portion of the laminate according to the thickness of the paste layer. Since a metal paste to be an electrode pad is applied to this convex portion and baked, a wiring board having a convex portion on the upper surface of the insulating substrate and a large number of electrode pads formed on this convex portion is manufactured. be able to. And, since the solder bumps are formed on the electrode pads of the wiring board and the solder bumps are pressed from above to align the heights of the upper surfaces of the solder bumps, the solder bumps have the same height, and the insulating substrate A wiring board with solder bumps with reduced cracks can be produced.

It is sectional drawing which shows an example of embodiment of the wiring board of this invention. It is sectional drawing which shows an example of embodiment of the wiring board with a solder bump of this invention. It is sectional drawing which shows the other example of embodiment of the wiring board of this invention. It is sectional drawing which shows an example of embodiment of the electronic device of this invention. (A) And (b) is sectional drawing which shows an example of the manufacturing method of the wiring board with a solder bump of this invention in order of a process, respectively. (A)-(c) is sectional drawing which shows an example of the manufacturing method of the wiring board with a solder bump of this invention in order of a process, respectively. It is sectional drawing which shows 1 process in the other example of the manufacturing method of the wiring board with a solder bump of this invention.

  A wiring board, a wiring board with solder bumps, an electronic device, and a wiring board with solder bumps according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing an example of an embodiment of a wiring board according to the present invention, and FIG. 2 is a cross-sectional view showing an example of an embodiment of a wiring board with solder bumps according to the present invention. 1 and 2, 1 is an insulating substrate, 1a is an insulating layer, 1b is a mounting portion, 2 is an electrode pad, and 3 is a through conductor. A semiconductor element mounting portion 1b is provided on the upper surface of an insulating substrate 1 formed by laminating a plurality of insulating layers 1a. A plurality of electrode pads 2 are formed on the mounting portion 1b, and penetrates the insulating layer 1a in the thickness direction. The wiring board 9 is basically configured by connecting the conductor 3 to the electrode pad 2.

  The insulating substrate 1 has a convex portion 1c on the upper surface, and the upper surface of the convex portion 1c is a semiconductor element mounting portion 1b, and the mounting portion 1b, that is, the upper surface of the convex portion 1c An electrode pad 2 is formed.

  A solder bump 5 is bonded to each of the plurality of electrode pads 2 of the wiring substrate 9 to form a wiring substrate 19 with solder bumps. The solder bump 5 is bonded to the electrode pad 2 by a method (reflow treatment) in which a solder material to be the solder bump 5 is applied to the surface of the electrode 2, heated and melted, and then cooled and welded. .

  Further, the solder bumps 5 are pressed from the upper side, and the upper surfaces are aligned at the same height. Specifically, the upper surfaces of the plurality of solder bumps 5 are uniformly pressed from above by using a coining device (so-called coining). The coining apparatus mainly includes a mounting table having a flat surface (mounting surface) on which the wiring substrate 9 is placed, and a plurality of solder bumps 5 on the wiring substrate 9 that are positioned parallel to the mounting surface. A press part having a flat surface that can be pressed together on all the upper surfaces thereof, and a drive part for supplying a force (pressure) for pressing the solder bumps 5 by moving the press part. Yes. The flat surface of the press part of the coining device is pressed against the upper surfaces of the plurality of solder bumps 5 at the same time, and this press part is moved downward (pressed) by the drive part, whereby each of the plurality of solder bumps 5 has a thickness. While being deformed in the direction, the upper surfaces thereof can be aligned with the flat surface of the press portion so as to have the same height.

  As shown in FIG. 3, a semiconductor element 10 is mounted on a wiring board 19 with solder bumps, and an electrode (no symbol) of the semiconductor element 10 is bonded to an electrode pad 2 via a solder bump 5 to thereby form an electronic device 29. As a semiconductor device is formed. FIG. 3 is a cross-sectional view showing an example of an embodiment of the electronic device 29 of the present invention. In FIG. 3, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals.

  In the example shown in FIGS. 1 to 3, a connection terminal 6 is formed on a portion of the upper surface of the insulating substrate 1 other than the mounting portion 1 b, and a conductive connection material 7 is attached to the connection terminal 6. An electronic component 11 other than the semiconductor element 10, such as a capacitor element (ceramic capacitor), a resistor, or a sensor element, is electrically and mechanically connected to the connection terminal 6 by a conductive connection material 7. These electronic components 11 form, for example, an electronic circuit together with the semiconductor element 10 to supply a reference potential, perform filtering, and the like.

  According to the wiring substrate 9 having the above configuration, the insulating substrate 1 has the convex portion 1c on the upper surface, and the upper surface of the convex portion 1c is the mounting portion 1b of the semiconductor element 10, and the mounting portion 1b has an electrode pad. 2 is formed, the height of the upper surface of the insulating substrate 1 is higher in the mounting portion 1b, that is, in the portion where the many electrode pads 2 are disposed than in the other portions. Therefore, even if a concave warp occurs on the upper surface of the insulating substrate 1, the upper surface of the insulating substrate 1 is suppressed from becoming higher than the solder bump 5 on the electrode pad 2.

  Therefore, after the solder bumps 5 are formed on the electrode pads 2, the coining device is prevented from coming into contact with the upper surface of the insulating substrate 1 outside the mounting portion 1b when the height of the solder bumps 5 is adjusted using the coining device. Thus, the generation of cracks in the insulating substrate 1 can be suppressed.

  Further, according to the wiring board 19 with solder bumps having the above-described configuration, the solder bumps 5 are welded to the wiring board 9 having the above-described configuration, and the solder bumps 5 are pressed from above so that the height of the upper surface is made uniform. Therefore, the semiconductor element 10 can be mounted without being tilted, and the crack of the insulating substrate 1 at the time of coining is suppressed as in the case of the wiring substrate 9. Accordingly, it is possible to provide a wiring board 19 with solder bumps in which the height of the plurality of solder bumps 5 is uniform and cracks in the insulating substrate 1 are suppressed and a highly reliable electronic device can be manufactured.

  Also, according to the electronic device 29 having the above configuration, the semiconductor element 10 is mounted on the wiring substrate 19 with solder bumps having the above configuration and the mounting portion 1b of the wiring substrate 19 with solder bumps, and the electrodes are connected to the solder bumps 5. Since the semiconductor element 10 is connected to the solder bumps 5 having the same height, the electronic device 29 in which the inclination of the semiconductor element 10 is suppressed can be provided. Moreover, since the crack of the insulating substrate 1 is suppressed, the reliability as the electronic device 29 is high.

  Hereafter, each part which comprises the said wiring board 9, the wiring board 19 with a solder bump, and the electronic device 29 is demonstrated in detail.

  The insulating substrate 1 is a base for mounting and holding an electronic component including the semiconductor element 10, and is formed in a square plate shape having a side length of about 20 to 60 mm, for example. The thickness of the insulating substrate 1 is appropriately set according to conditions such as mechanical strength, electrical function, and low profile required for the wiring substrate 9.

  The insulating substrate 1 is a ceramic sintered body such as a glass ceramic sintered body, an aluminum oxide sintered body, an aluminum nitride sintered body, a silicon carbide sintered body, a silicon nitride sintered body, and a mullite sintered body. An insulating layer 1a made of is laminated and formed.

  The insulating substrate 1 can be manufactured as follows if each insulating layer 1a is made of a glass ceramic sintered body, for example.

First, a raw material powder mainly composed of a glass powder such as borosilicate glass, lithium oxide glass or phosphate glass containing silicon dioxide and a ceramic powder such as aluminum oxide, magnesium oxide or calcium oxide is used as an organic solvent. A ceramic green sheet is produced by kneading with a binder and forming into a sheet by a forming method such as a doctor blade method or a lip coater method. Next, the ceramic green sheet is cut into a predetermined shape and size, and a plurality of ceramic green sheets are laminated. Thereafter, the insulating substrate 1 can be manufactured by firing the laminate of the ceramic green sheets at a firing temperature of about 900 to 1000 ° C.

  The mounting portion 1b on the upper surface of the insulating substrate 1 is a part such as a rectangle or an ellipse on which an electronic component including the semiconductor element 10 is mounted. In the example shown in FIGS. The central portion is the mounting portion 1b.

  The electrode pad 2 is for facing the electrodes of the semiconductor element 10 mounted on the mounting portion 1b and electrically and mechanically connecting the electrodes (so-called flip-chip connection). A plurality of electrode pads 2 are arranged in a pattern such as a vertical and horizontal arrangement on the mounting portion 1b.

  The electrode pad 2 is, for example, a pattern such as a circular shape, an elliptical shape, a quadrangular shape, or a quadrangular shape with corners formed into arc shapes. The electrode pad 2 is formed in a circular shape having a diameter of about 75 to 150 μm, for example, when the electrodes of the semiconductor element 10 are connected by the flip chip method.

  The electrode pad 2 is made of a metal material such as copper, silver, palladium, platinum, gold, copper-tungsten, molybdenum, or manganese. If the electrode pad 2 is made of copper, a metal paste prepared by kneading copper powder together with an organic solvent and a binder is applied to a portion to be the mounting portion 1b on the main surface of the ceramic green sheet to be the insulating substrate 1. It can be formed by printing in a pattern of a predetermined electrode pad 2 and co-firing with a ceramic green sheet.

  The electrode pad 2 is connected to a through conductor 3 that penetrates the insulating layer 1a in the thickness direction, and the internal conductor 4a disposed between the insulating layers 1a and the lower surface of the insulating substrate 1 through the through conductor 3, for example. Are electrically connected to the external connection pads 4b.

  The through conductor 3, the inner conductor 4 a and the pad 4 b are formed using the same material as the electrode pad 2 and by the same method (printing of a metal paste or the like). In this case, the ceramic green sheet for producing the insulating substrate 1 is previously subjected to punching such as mechanical punching or laser processing to form a through hole penetrating in the thickness direction, and the inside of the through hole is formed. If the metal paste is filled and fired, the through conductor 3 can be formed.

  Note that a glass component or the like may be added to the through conductor 3 or the like in order to improve the adhesion to the insulating substrate 1 by approximating the thermal expansion coefficients of the insulating substrate 1. .

  The internal conductor 4a is, for example, a ground conductor layer for supplying a ground potential or a power potential to the semiconductor element 10 or a conductor layer (no symbol) such as a power conductor layer, between the semiconductor element 10 and another electronic component 11, a semiconductor A wiring conductor (no reference) for electrical connection between the element 10 and the pad 4b, between the through conductor 3 and the ground conductor layer or the power conductor layer, and the like.

The wiring conductors are led out (so-called unfolded) outward from the mounting portion 1b in plan view sequentially from the outer periphery of the vertical and horizontal arrangements of the through conductors 3 (electrode pads 2). The through conductor 3 does not need to extend to the lower side of the layer where the development is performed, and thus penetrates to the insulating layer 1a immediately above the layer where the development is performed. Therefore, the number of insulating layers 1a through which the through conductor 3 penetrates is smaller in the outer peripheral portion than in the central portion of the mounting portion 1b. In other words, in the central portion of the mounting portion 1b, the through conductor 3 penetrates more insulating layers 1a than the outer peripheral portion (the through conductor 3 is long).

  The solder bump 5 is a conductive connecting material for electrically and mechanically connecting the electrode pad 2 of the wiring board 9 and the electrode of the semiconductor element 10, for example, a tin-lead eutectic solder material, It is formed of a lead-free solder material such as tin-silver, tin-silver-copper, or tin-silver-bismuth.

  The solder bump 5 is bonded to the upper surface of the electrode pad 2 in advance, and the electrode pad 2 is bonded to the upper surface of the solder bump 5 by aligning and bonding the electrodes on the main surface of the semiconductor element 10 downward. And the electrode are joined. That is, as described above, the solder bumps 5 are joined to the electrode pads 2 of the wiring board 9 to produce the wiring board 19 with solder bumps, and then the semiconductor element 10 is mounted on the wiring board 19 with solder bumps. A device 29 is produced.

  The solder bump 5 is bonded to the electrode pad 2 by welding. For example, a tin-silver-copper solder paste is applied to the surface of the electrode pad 2 and heated and cooled and solidified to form a bump. It is formed by doing.

  When bonding the solder bump 5 to the electrode pad 2, it is preferable that a plating layer of nickel, gold, or the like is previously deposited on the surface of the electrode pad 2 in consideration of solder wettability. In consideration of suppressing the occurrence of electromigration between the electrode pad 2 and the solder bump 5, it is preferable to weld the solder bump 5 directly on the surface of the electrode pad 2 made of copper.

  Further, as described above, the plurality of solder bumps 5 on the wiring board 19 with solder bumps need to have the same height on the upper surface between the solder bumps 5. This is because the semiconductor element 10 is mounted on the wiring board 19 with solder bumps without tilting. In order to make the heights of the upper surfaces of the plurality of solder bumps 5 uniform, the plurality of solder bumps 5 are collectively pressed from above by the coining.

  The height of the solder bump 5 needs to be the same as the height of the upper surface between the plurality of solder bumps 5 arranged on the mounting portion 1b, but the height itself is obtained by the electronic device 29. What is necessary is just to set suitably according to conditions, such as long-term connection reliability, low profile, and workability | operativity at the time of the semiconductor element 10 mounting.

  For example, as the height of the solder bump 5 is increased, the stress due to the difference in thermal expansion coefficient between the semiconductor element 10 and the insulating substrate 1 can be relaxed by the solder bump 5, and the height varies. It is easy to align the heights of the plurality of solder bumps 5. On the other hand, as the height of the solder bump 5 is lowered, an electrical short circuit between the solder bumps 5 can be suppressed.

  As described above, in the mounting portion 1b in which the plurality of electrode pads 2 are arranged, the through conductors 3 connected to these electrode pads 2 are formed from the electrode pads 2 to the inside of the insulating substrate 1. . In addition, the through conductor 3 penetrates more insulating layers 1a in the thickness direction in the central portion than the outer peripheral portion of the mounting portion 1b (the ratio of the volume occupied by the through conductor 3 in the insulating substrate 1 is Larger). In addition, since the metal paste serving as the through conductor 3 has a larger shrinkage during firing than the ceramic green sheet serving as the insulating layer 1a, the insulating substrate 1 is likely to be deformed such that the mounting portion 1b is concave.

On the other hand, a convex portion 1c is provided on the upper surface of the insulating substrate 1, and a plurality of electrode pads 2 are formed by using the upper surface of the convex portion 1c as a mounting portion 1b. Contact between the insulating substrate 1 and the press portion is suppressed, and generation of cracks in the insulating substrate 1 is suppressed.

  In this case, the concave deformation generated in the mounting portion 1b of the insulating substrate 1 is, for example, about 15 to 30 μm at the central portion of the mounting portion 1b and about 5 to 20 μm at the outer peripheral portion. Further, the height of the solder bump 5 in an unpressurized state is about 40 to 50 μm. When the unpressurized solder bumps 5 are pressed by the press unit so that the heights of the upper surfaces are made uniform, the height of the solder bumps 5 can be suppressed to about 15 to 35 μm. In order to prevent contact between the press part and the insulating substrate 1 (particularly, a part of the upper surface adjacent to the mounting part 1b) at the time of pressurization, the height of the convex part 1c is set to be an insulation at a part adjacent to the mounting part 1b. It is preferable that the height is about 30 to 100 μm or more higher than the upper surface of the substrate 1.

  The convex portion 1c is formed, for example, between the upper surface of the insulating substrate 1 and the interlayer of the insulating layer 1a, in addition to the insulating layer 1a forming the insulating substrate 1, other insulating layers or metal layers (not shown in FIG. 1). ). A method of manufacturing the wiring board 19 with solder bumps provided with the convex portion 1c will be described in detail later.

  FIG. 3 is a cross-sectional view of another example of the embodiment of the wiring board of the present invention. In FIG. 3, the same parts as those in FIG. In the example shown in FIG. 3, at least one of the metal layer 8a and the other insulating layer 8b is interposed between the insulating layers 1a immediately below the convex portion 1c, and the thicknesses of the metal layer 8a and the other insulating layer 8b are the same as those described above. However, the outer peripheral portion of the convex portion 1c in plan perspective is thinner than the central portion.

  The metal layer 8a and the other insulating layer 8b are intervening layers 8 interposed between the insulating layers 1a in order to partially raise the upper surface of the insulating substrate 1 to form the convex portions 1c. FIG. 3 shows an example in which the intervening layer 8 is thinner than the central portion (hereinafter sometimes simply referred to as the outer peripheral portion or the central portion of the intervening layer 8) at the outer peripheral portion of the convex portion 1c in plan perspective. .

  Thus, when the thickness of the intervening layer 8 for forming the convex portion 1c is reduced in the outer peripheral portion of the convex portion 1c, it is advantageous in increasing the flatness of the upper surface of the convex portion 1c. . That is, for example, according to the concave warp generated on the upper surface of the insulating substrate 1, the outer peripheral portion of the upper surface of the convex portion 1c tends to be higher than the central portion. On the other hand, if the thickness of the intervening layer 8 is reduced in the outer peripheral portion as described above, the height between the outer peripheral portion and the central portion of the upper surface of the convex portion 1c that may be caused by warping. This difference can be canceled by the difference in the thickness of the intervening layer 8. Therefore, the flatness of the upper surface of the convex portion 1c can be further increased.

  Further, as shown in FIG. 3, when the thickness of the outer peripheral portion of the intervening layer 8 is gradually reduced from the central side toward the outer side, the inclination angle of the side surface of the convex portion 1c (convex shape in the longitudinal section) It is easy to keep the angle between the side surface of the portion 1c and the upper surface of the insulating substrate 1 smaller. In this case, the concentration of stress such as thermal stress in the outer peripheral portion of the convex portion 1c (particularly, the boundary between the side surface of the convex portion 1c and the upper surface of the insulating base 1) can be reduced. Therefore, mechanical destruction such as cracks of the convex portion 1c due to the stress or the like can be more effectively suppressed.

  Examples of the material for forming the other insulating layer 8b include a material such as a glass ceramic sintered body similar to that for forming the insulating layer 1a. In this case, the ratio of the glass component and the like may be adjusted as appropriate as compared with the glass ceramic sintered body forming the other insulating layer 8b to enhance the bonding property with the upper and lower insulating layers 1a.

The metal layer 8a of the intervening layer 8 can be formed by using the same metal material as the electrode pad 2 and the like (the through conductor 3, the inner conductor 4a and the pad 4b) and by the same method. In the example shown in FIG. 3, the metal layer 8 a is connected to the lower end of the through conductor 3. In this case, in order to ensure electrical insulation between the through conductors 3, it is necessary to dispose another insulating layer 8b between the metal layers 8a.

  If the metal layer 8a is not in contact with the through conductor 3, the intervening layer 8 can be formed only of the metal layer 8a. Further, the intervening layer 8 may be formed of only the other insulating layer 8b.

  In addition, although the insulating layer 1a and the other insulating layer 8b are integrally sintered at the time of the said baking, the interface of both can be identified, for example by cross-sectional observation with a microscope.

  What is necessary is just to adjust the thickness of the intervening layer 8 suitably according to the height of the convex-shaped part 1c which it is going to form. Moreover, what is necessary is just to set suitably how much the thickness in the outer peripheral part of the intervening layer 8 is made thin with respect to the thickness in a center part according to the grade of the concave curvature which arises in the upper surface of the insulation base | substrate 1.

  In addition, in the example shown in FIG. 3, the protrusion part 1d is formed along the outer periphery of the convex-shaped part 1c. The protrusion 1d is made of, for example, an epoxy resin or a silicone resin. The protrusion 1d is preferably made of a material having a lower elastic modulus than the convex portion 1c.

  The projecting portion 1d is formed, for example, at the same height as the solder bump 5 and is used as a reference for positioning the electronic component 11 in the height direction when the electronic component 11 is connected to the solder bump 5. The

  Moreover, the protrusion part 1c may be formed in shapes, such as a frame shape which surrounds the mounting part 1a by planar view, or cyclic | annular form, for example. Such a projecting portion 1c is formed when the resin material (so-called underfill) (not shown) is interposed between the electronic component 11 mounted on the mounting portion 1a and the mounting portion 1a. It can also function as a dam for preventing it from flowing out of 1a.

  Further, the convex portion 1c is advantageous in that it is thicker in order to prevent contact between the coining device and the insulating substrate 1 at the time of coining, but if it is too thick, the wiring substrate 9, the wiring substrate 19 with solder bumps, and the electronic device There is a possibility that it will become unsuitable for reduction in height and mechanical strength in 29, and productivity and economy may be lowered. Therefore, it is preferable to suppress the convex portion 1c as low as possible within the range in which contact between the press portion and the insulating substrate 1 can be prevented as described above.

  In addition, it is preferable to form the convex portion 1c over the entire range where the electrode pad 2 is disposed. However, if the convex portion 1c is formed beyond the range where the electrode pad 2 is disposed, the insulating portion is insulated. There is a possibility that other portions of the upper surface of the substrate 1 are higher than the portion where the electrode pads 2 are formed, and the effect of suppressing cracks during the coining may be insufficient. Therefore, it is preferable that the outer periphery of the convex portion 1c is located just inside the outer periphery of the region where the electrode pad 2 is disposed (mounting portion 1b).

  In the wiring board 19 with solder bumps, when the electrode pad 2 is made of copper and glass is added to a portion connected to the through conductor 3 of the electrode pad 2, a more reliable electronic device 29 is obtained. A wiring board 19 with solder bumps that can be produced can be provided.

  That is, in many cases, glass is added to the through conductor 3 in order to match characteristics such as a thermal expansion coefficient with the insulating substrate 1 as described above. Similarly, the connection portion of the electrode pad 2 to which the glass is added to the through conductor 3 is reinforced by the glass with respect to the through conductor 3, so that the mechanical connection strength between the electrodes can be improved.

  Further, since the electrode pad 2 is made of copper and glass is not added to the upper surface side to be joined to the solder bump 5, the wettability of the solder bump 5 (solder paste or the like that becomes the solder bump 5) to the electrode pad 2 is good. It is. For this reason, it is possible to obtain a wiring board 19 with solder bumps in which the bonding strength between the electrode pad 2 and the through conductor 3 is high and the connection reliability between the electrode pad 2 and the solder bump 5 is high.

  The wiring board 19 with solder bumps includes a connection terminal 6 on which the electronic component 11 is mounted in a region other than the convex portion 1c on the upper surface of the insulating substrate 1, and a conductive connection material on the connection terminal 6. 7 is formed, and when the height of the conductive connecting material 7 is lower than the height of the solder bump 5, it is possible to mount an electronic component 11 (capacitor or the like) in addition to the semiconductor element 10. A practical wiring board 19 with solder bumps can be obtained.

  Further, in this case, since the conductive connecting material 7 is lower than the solder bump 5, even if the solder bump 5 is pressed by a coining device having a relatively large area of the lower surface of the press portion, the press portion It is suppressed that pressurization is prevented by contacting the conductive connection material 7 on the connection terminal 6. Therefore, it is possible to provide the wiring board 19 with solder bumps in which the heights of the solder bumps 5 are evenly arranged.

  In addition, since it is not necessary to accurately match the area of the pressing portion of the coining apparatus with the area of the semiconductor element mounting portion 1b, a plurality of types of wiring boards with solder bumps (not shown) having different areas of the semiconductor element mounting portion 1b. ) To the same coining apparatus. Therefore, the productivity and economy are also better.

  The semiconductor element 10 is mounted on the wiring board 19 with solder bumps having any one of the above configurations, and an electronic device 29 as shown in FIG. 4 is formed, for example. In the example shown in FIG. 4, the pad 4b on the lower surface of the electronic device 29 is electrically and mechanically connected to a predetermined portion of the external electric circuit (not indicated) via a connecting material (not indicated) such as solder or conductive adhesive. It is connected to the. As a result, the electrode (not shown) of the semiconductor element 10 of the electronic device 29 is electrically connected to the external electric circuit, and signals are exchanged between the semiconductor element 10 and the external electric circuit.

Here, the effect of suppressing cracks in the insulating substrate 1 in the wiring substrate 9 and the wiring substrate 19 with solder bumps of the present invention will be described with specific examples. In a specific example, the insulating substrate 1 was produced by stacking 18 insulating layers 1a made of a glass ceramic sintered body (borosilicate glass-aluminum oxide system) having a thickness of about 0.1 to 0.2 mm. The insulating substrate 1 in a plan view has a square shape with a side length of about 50 mm. By interposing another insulating layer made of a ceramic sintered body having a thickness of about 0.1 mm between the insulating layers 1a, a convex portion 1c is provided at the central portion of the upper surface of the insulating substrate 1, and the upper surface of this central portion is formed. About 8000 circular electrode pads 2 (made of copper) having a diameter of about 100 μm were arranged in a vertical and horizontal arrangement as the mounting portion 1b (a square shape having a side length of about 19 mm). The other insulating layer was formed by applying a ceramic paste produced using the same material as that of the insulating layer 1a between the ceramic green sheets to be the insulating layer 1a and firing them simultaneously. A solder paste made of tin-silver-copper solder is applied to these electrode pads 2, heated and cooled to join the solder bumps 5 (unpressurized), and then the solder bumps 5 are attached using a coining device. By pressing from above, a wiring board 19 with solder bumps of a specific example was produced.

  Further, as a comparative example, a wiring board with solder bumps (not shown) produced in the same manner as the wiring board 19 with solder bumps of the above specific example except that the convex portion 1c is not provided (no other insulating layer is interposed). ) Was prepared.

  About 50 of these specific wiring board 19 with solder bumps and comparative wiring board with solder bumps, the presence or absence of cracks in the insulating substrate (1) was confirmed by inspection (visually) using a binocular microscope. . As a result, in the wiring board with solder bumps of the present invention, no cracks were found in the insulating substrate 1, whereas in the wiring board with solder bumps of the comparative example, three were adjacent to the mounting portion. Cracks were generated on the upper surface of the insulating substrate at the portions. Thereby, the effect which suppresses the crack of the insulated substrate 1 in the wiring board 9 and the wiring board 19 with a solder bump of this invention was able to be confirmed.

  Next, a method for manufacturing a wiring board with solder bumps according to the present invention will be described with reference to FIGS. 5 (a) to 5 (d) and FIGS. 6 (a) to 6 (c) are cross-sectional views illustrating the method of manufacturing a wiring board with solder bumps according to the present invention in the order of steps. In FIGS. 5 and 6, the same parts as those in FIGS.

  The wiring board with solder bumps manufactured by the manufacturing method of the present invention is similar to the wiring board 19 with solder bumps of the present invention described above, in which a semiconductor element is mounted on the upper surface of the insulating substrate 1 in which a plurality of insulating layers 1a are laminated. A plurality of electrode pads 2 having a portion 1b and connected to the electrodes of the semiconductor element 10 are formed on the mounting portion 1b, and the through conductor 3 penetrates the insulating layer 1a in the thickness direction through these electrode pads 2. Are connected to each other, and a solder bump 5 joined to the electrode pad 2 is provided.

Specifically, as shown in FIG. 5A, a plurality of ceramic green sheets 21 each serving as an insulating layer 1 a are prepared, and a region (a semiconductor element mounting portion 1 b) is formed on a part of the ceramic green sheet 21. A step of forming a through-hole (no symbol) penetrating the ceramic green sheet 21 in the thickness direction in the region to be the mounting portion 1b;
A step of printing the metal paste 22a to be the plurality of electrode pads 2 on the main surface of the ceramic green sheet 21 in the mounting portion 1b, and filling the metal paste 22b to be the through conductor 3 in the through hole;
As shown in FIG. 5B, at least one of the metal paste 25a and the ceramic paste 25b (paste layer 25) is placed between the upper and lower ceramic green sheets 21 immediately below the region to be the mounting portion 1b. ) In a layered manner to form a laminate 28, and then firing the laminate 28;
As shown in FIG. 6A, the solder paste 55 is printed on each of the plurality of electrode pads 2, and the solder paste 55 is heated, so that each of the plurality of electrode pads 2 is shown in FIG. 6B. Forming solder bumps 5;
And pressurizing the plurality of solder bumps 5 from above to align the heights of the upper surfaces of the plurality of solder bumps 5.

  According to the method for manufacturing a wiring board with solder bumps of the present invention, the metal paste 25a is provided between the upper and lower ceramic green sheets 21 including the above-described steps, and a plurality of ceramic green sheets 21 immediately below the region to be the mounting portion 1b. And at least one of the ceramic paste 25b (paste layer 25) is laminated in a layered manner to form the laminated body 28. Therefore, in the laminated body 28 to be the insulating substrate 1, at least one of the metal paste 25a and the ceramic paste 25b is formed. In the portion where the (paste layer 25) is interposed, the convex portion 1c can be formed on the upper surface in the region to be the mounting portion 1b of the laminate 28 in accordance with the thickness of the paste layer 25. Since the metal paste 22a to be the electrode pad 2 is applied to the convex portion 1c and baked, the insulating substrate 1 has the convex portion 1c on the upper surface, and a large number of electrode pads 2 are formed on the convex portion 1c. The printed wiring board 9 can be manufactured. Then, since the solder bumps 5 are formed on the electrode pads 2 of the wiring board 9 and the solder bumps 5 are pressed from above to align the height of the upper surface of the solder bumps 5, FIG. As shown, a wiring board 19 with solder bumps in which the heights of the solder bumps 5 are uniform and cracks in the insulating substrate 1 are suppressed can be manufactured.

  Hereafter, each said process is demonstrated in detail.

  The plurality of ceramic green sheets 21 to be the insulating layer 1a to be laminated in the step shown in FIG. 5A can be prepared by using the same material as in the case of the wiring board 9 of the present invention described above and by the same method. . That is, for example, a raw material powder such as ceramic powder such as borosilicate glass or aluminum oxide is formed into a sheet shape by a forming method such as a doctor blade method together with an organic solvent or a binder to form a band-shaped ceramic green sheet (not shown) Is cut into a predetermined shape and dimensions, and a plurality of ceramic greens 21 each serving as the insulating layer 1a of the insulating substrate 1 can be manufactured.

  For a part of these ceramic green sheets 21, a rectangular area or the like serving as the mounting portion 1b is temporarily set, and in this area, a through hole (not indicated) that penetrates the ceramic green sheet 21 in the thickness direction is formed. Examples of the method for forming the through hole include mechanical drilling using a metal pin and laser processing.

  For example, the ceramic green sheet 21 is positioned and set on a mold, and an area located at a predetermined position from the outer periphery of the ceramic green sheet 21 is defined as a mounting portion 1b. A through hole can be formed by drilling the ceramic green sheet 21 using a metal pin while aligning.

  In the mounting portion 1b, the metal paste 22a to be the electrode pad 2 printed on the main surface of the ceramic green sheet 21 and the metal paste 22b to be the through conductor 3 filling the through hole are, for example, the case of the wiring board 9 of the present invention described above. Can be prepared by the same method (kneading with an organic solvent and a binder) using the same material (copper, silver, etc.).

  The printing of the metal paste 22a, 22b on the main surface of the ceramic green sheet 21 on the part to be the mounting portion 1b and the filling into the through hole are, for example, screen printing using a screen printing method or vacuum suction into the through hole. It can be performed by a method such as law.

  Further, in the example shown in FIG. 5A, the ceramic green sheet 21 may be positioned between the upper and lower ceramic green sheets 21 in a later step, or the lower surface of the laminated body 28. Further, other metal pastes 22c other than the metal paste 22a serving as an electrode pad and the metal paste 22b serving as a through conductor are also printed. The other metal paste 22c is, for example, the inner conductor 4a of the insulating substrate 1, the external connection pad 4b on the lower surface, and the like. The other metal paste 22c can also be produced by the same method using the same material as the metal pastes 22a and 22b, and can be printed on the ceramic green sheet 21 by the same method.

  In this step, for some of the ceramic green sheets 21, at least one of the metal paste 25a and the ceramic paste 25b (paste layer 25) to be interposed between the ceramic green sheets 21 in the next step is applied. At least one of the metal paste 25a and the ceramic paste 25b is interposed between the ceramic green sheets 21 immediately below the region to be the mounting portion 1b at the time of stacking, and the convex portion 1c is formed on the upper surface of the laminate 28 in the mounting portion 1b. It is for forming.

  In the example of the embodiment shown in FIG. 5 and FIG. 6, a part of the metal paste 25a that forms the paste layer 25 is directly connected to the metal paste 22b or other metal paste 22c serving as a through conductor. The metal paste 25a becomes the metal layer 8a after firing, and can be used as a conductor for electrical connection such as between the upper and lower through conductors 3 or between the through conductor 3 and the internal conductor 4a.

  As the metal paste 25a for forming the paste layer 25, the same metal pastes 22a and 22b as the electrode pads and through conductors can be used. Further, as the ceramic paste 25b, it is possible to use a paste made by adjusting the amount of the organic solvent, the binder and the like using the same material as that for producing the ceramic green sheet 21. The metal paste 25a and the ceramic paste 25b can be applied by, for example, a screen printing method.

  The thickness of the paste layer 25 is adjusted according to the height of the convex portion 1c to be formed. In addition, the range in which the paste layer 25 is formed in a plan view needs to include at least the range in which the metal paste 22a that becomes the electrode pad 2 is printed when the ceramic green sheets 21 are laminated. It is preferable to match the range surrounded by the outer periphery of the range such as a quadrangular shape on which the paste 22a is printed.

  In the step shown in FIG. 5 (b), the laminate 28 produced by laminating these ceramic green sheets 21 has upper and lower ceramics directly below the mounting portion 1b (for example, in a range that overlaps the mounting portion 1b in plan view). A paste layer 25 is interposed between the green sheets 21.

  For the lamination of the ceramic green sheets 21, for example, the upper ceramic green 21 is laminated on the lower ceramic green sheet 21 while being aligned at the positions of the outer sides, etc., and then pressed and brought into close contact with each other. By doing.

  The laminated body 28 has a convex portion 1 c formed on the upper surface according to the thickness of the paste layer 25. In this case, in order to form the convex portion 1c on the upper surface of the laminate 28 in accordance with the thickness of the paste layer 25, the ceramic green sheet is placed with the lower surface side of the laminate 28 placed on a flat table or the like. It is desirable to perform 21 layers. Since pressurization is performed in a state where the lower surface side of the laminated body 28 is placed on a flat base, protrusion of the laminated body 28 to the lower surface side at a portion where the paste layer 25 is interposed is suppressed. Therefore, the convex portion 1 c corresponding to the thickness of the paste layer 25 can be formed on the upper surface side of the laminate 28. Further, in the pressurizing jig that applies pressure when laminating, when the shape of the surface that contacts the upper surface of the laminated body 28 is a gentle concave shape from the outer peripheral portion to the central portion, only the central portion of the upper surface is reliably projected. It becomes possible.

The laminated body 28 is fired in the same manner as in the case of the wiring board 9 of the present invention described above (about 900 to 1000 ° C.
Firing at a certain firing temperature). As described above, the insulating substrate 1 depends on the difference between the shrinkage amount of the ceramic green sheet 21 and the shrinkage amount of the metal pastes 22a, 22b, and 22c and the shrinkage behavior (shrinkage start temperature, shrinkage end temperature, etc.) during firing. Tends to deform into a concave shape in the mounting portion 1b.

  By firing the laminated body 28, for example, as shown in FIG. 1, a wiring board having a convex portion 1c on the upper surface of the insulating substrate 1, and the upper surface of the convex portion 1c as a semiconductor element mounting portion 1b. 9 can be produced. A solder paste 55 is applied to the electrodes 2 of the wiring board 9.

  The convex portion 1c is formed by another method in which the paste layer 25 formed using the metal paste 25a or the ceramic paste 25b is fired simultaneously with the laminated body 28, and the paste layer 25 is sintered. This is because an insulating layer (no symbol) is interposed between the insulating layers 1a.

The solder paste 55 to be printed on each of the plurality of electrode pads 2 in the step shown in FIG. 5A can be prepared using the same material as that of the wiring board 19 with solder bumps of the present invention described above. That is, the solder paste 55 can be prepared by using a solder material such as tin-silver-copper and kneading these solder material powders with an organic solvent or the like. Also,
The solder paste 55 can be printed on the electrode 2 by a method such as a screen printing method.

  When the solder paste 55 printed on the electrode 2 is heated and melted once, unnecessary organic solvent or the like is removed and then solidified, the solder bump 5 is obtained. That is, the solder bump 5 shown in FIG. 6B is joined to the electrode pad 2 by welding.

  The solder paste 55 can be heated by, for example, a method (reflow) in which the insulating substrate 1 on which the solder paste 55 is printed on the electrode 2 is integrally heated in an electric furnace. For example, when the solder paste 55 uses tin-silver-copper solder, the heating temperature is set to about 230 to 240 ° C.

  In the step shown in FIG. 6B, a coining device can be used as a device used when pressurizing the solder bumps 5 formed on each of the plurality of electrode pads 2 from above. As in the case of the above-described wiring board 19 with solder bumps of the present invention, the coining apparatus has a mounting table (not shown) and the upper surfaces of all the solder bumps 5 on the wiring board 9 mounted on the mounting table. And a drive unit (not shown) having a flat surface that can be pressed together.

  The condition for pressurizing the solder bump 5 by coining is, for example, that the solder bump 5 is made of tin-silver-copper solder, and the height is kept low in the range of 20 to 30 μm (that is, the deformation of the solder bump 5 in the height direction). If the amount is in the above range), it may be set to about 10 MPa.

  In this step, the convex portion 1c is formed on the upper surface of the insulating substrate 1, the upper surface of the convex portion 1c is used as the mounting portion 1b, and the plurality of electrode pads 2 are disposed. Even if the substrate 1 is deformed in a concave shape in the mounting portion 1b, the press portion 24 is effectively suppressed from coming into contact with the upper surface of the insulating substrate 1. Therefore, the generation of cracks in the insulating substrate 1 due to contact with the press part 24 (pressure applied via the press part 24) is suppressed.

  Through the above-described steps, a wiring board 19 with solder bumps is produced in which the heights of the solder bumps 5 are uniform and cracks in the insulating substrate 1 are suppressed as shown in FIG.

  In this case, for example, even if some unevenness is generated on the upper surface of the mounting portion 1b according to the thickness of the internal conductor 4a between the portion with and without the internal conductor 4a, the solder bump caused by the unevenness The height variation of 5 can be eliminated by coining.

  In other words, the paste layer 25 is for making the entire mounting portion 1b higher than the other portions in the insulating substrate 1, and for making the heights of the plurality of electrode pads 2 in the mounting portion 1b equal to each other. It is not a thing.

  In this case, even if the entire upper surface of the insulating substrate 1 is flat, the contact of the press portion 24 with the insulating substrate 1 as described above can be generally suppressed. When the press part 24 is inclined and pressurizes the solder bumps 5, a part of the end of the press part 24 may come into contact with the upper surface of the insulating substrate 1 to generate a crack. When a crack occurs in the insulating substrate 1, the wiring substrate 9 becomes defective, resulting in a decrease in yield when the electronic device 29 is manufactured.

On the other hand, if there is the solder bump 5 on the upper surface of the convex portion 1c as described above, even if the press portion 24 is slightly inclined (for example, in a range less than the height of the convex portion 1c), the press portion 24 is. Is prevented from contacting the insulating substrate 1. Since coining itself can be redone, the wiring board 9 and the wiring board 19 with solder bumps do not become defective, and a decrease in yield when the electronic device 29 is manufactured can be suppressed.

  FIG. 7 is a cross-sectional view showing one step in another example of the embodiment of the method for manufacturing the wiring board with solder bumps of the present invention. In FIG. 7, the same parts as those in FIGS. 5 and 6 are denoted by the same reference numerals. In the example shown in FIG. 7, the thickness of the metal paste 25a and the ceramic paste 25b interposed between the upper and lower ceramic green sheets 21 in the above-described step of forming the laminated body 28 is set to the outer periphery of the region that becomes the mounting portion 1b in plan perspective. This is an example in which the portion is made thinner than the central portion (hereinafter sometimes simply referred to as the outer peripheral portion or the central portion).

  As described above, when the thickness of the paste layer 25 is reduced in the outer peripheral portion, the intervening layer 8 thinner than the central portion can be formed in the outer peripheral portion as described above, so that the upper surface of the convex portion 1c is flat. This is advantageous in manufacturing a wiring board 19 with solder bumps having high properties.

  In the example shown in FIG. 7, the thickness of the outer peripheral portion of the paste layer 25 is gradually reduced from the center side toward the outside. In such a case, as described above, since it is easy to suppress the inclination angle of the side surface of the convex portion 1c to be smaller, mechanical destruction such as cracks in the convex portion 1c due to stress is more effective. It can also be suppressed.

  In order to make the thickness at the outer peripheral portion of the paste layer 25 thinner than the thickness at the central portion, for example, the metal paste 25a and the ceramic paste 25b that are printed on the outer peripheral portion of the paste layer 25 have a relatively low viscosity. Thus, the outer peripheral portion of the printed pattern may be gently inclined.

DESCRIPTION OF SYMBOLS 1 ... Insulating substrate 1a ... Insulating layer 1b ... Mounting part 1c ... Convex part 1d ... Protruding part 2 ... Electrode pad 3 ... Penetration conductor 4a ... Internal conductor 4b ... Pad 5 ... Solder bump 6 ... Connection terminal 7 ... Conductive connection material 8a ... Metal layer 8b ... Other insulating layer 9 ... Wiring substrate
10 ・ ・ ・ ・ Semiconductor element
11 ... Electronic components
19 ... Wiring board with solder bumps
21 ... Ceramic green sheet
22a: Metal paste to be an electrode pad
22b ... Metal paste to be a through conductor
22c ・ ・ ・ Other metal paste
24 ... Press section
25 ... Paste layer
25a ・ ・ ・ Metal paste
25b Ceramic paste
28 ... Laminate
29 ... Electronic devices
55 ... Solder paste

Claims (8)

A semiconductor element mounting portion is provided on an upper surface of an insulating substrate formed by laminating a plurality of insulating layers, and a plurality of electrode pads connected to the electrodes of the semiconductor element are formed on the mounting portion. Each of which is connected to a through conductor that penetrates the insulating layer in the thickness direction,
The penetrating conductor penetrates more of the insulating layer in the central part than the outer peripheral part of the mounting part, the insulating substrate has a convex part on the upper surface, and the upper surface of the convex part is the semiconductor A wiring board comprising an element mounting portion and the electrode pad formed on the mounting portion being connected to the electrode of the semiconductor element via a solder bump. At least one of a metal layer and another insulating layer is interposed between the insulating layers immediately below the convex portion, and the thickness of the metal layer and the other insulating layer is the same as that of the convex portion in a plan view. The wiring board according to claim 1, wherein the outer peripheral portion is thinner than the central portion. A wiring board according to claim 1 or 2 and a solder bump bonded to the electrode pad of the wiring board, wherein the solder bump is pressed from the upper side so that the upper surface is aligned at the same height. A wiring board with solder bumps. The wiring board with solder bumps according to claim 3, wherein the electrode pad is made of copper, and glass is added to a portion of the electrode pad connected to the through conductor. A connection terminal on which an electronic component is mounted in a region other than the convex portion of the upper surface of the insulating substrate is provided, and a conductive connection material is formed on the connection terminal, which is higher than the height of the solder bump. The wiring board with solder bumps according to claim 3, wherein the conductive connecting material has a lower height. A wiring board with solder bumps according to any one of claims 3 to 5, and a semiconductor element mounted on the mounting portion of the wiring board with solder bumps and having electrodes connected to the solder bumps. An electronic device characterized by the above. A semiconductor element mounting portion is provided on the upper surface of an insulating substrate formed by laminating a plurality of insulating layers, and a plurality of electrode pads connected to the electrodes of the semiconductor element are formed on the mounting portion. A through-hole conductor that penetrates the insulating layer in the thickness direction is connected, and a wiring board in which a through-conductor that penetrates the insulating layer in the thickness direction is connected to each of the electrode pads, and is joined to the electrode pad. A method of manufacturing a wiring board with solder bumps comprising solder bumps,
A plurality of ceramic green sheets serving as the insulating layers are prepared, and a region for mounting the semiconductor element is provided in a part of the ceramic green sheet, and the ceramic green sheets are disposed in the thickness direction in the region to be the mounting portion. Forming a through-hole penetrating;
Printing the metal paste to be a plurality of the electrode pads on the main surface of the ceramic green sheet in the mounting portion, and filling the metal paste to be the through conductor in the through hole;
A plurality of the ceramic green sheets are laminated by laminating at least one of a metal paste and a ceramic paste between the upper and lower ceramic green sheets immediately below the region to be the mounting portion, to form a laminate, A step of firing the laminate;
Printing a solder paste on each of the plurality of electrode pads, heating the solder paste, and forming solder bumps on each of the plurality of electrode pads;
And a step of pressurizing the plurality of solder bumps from above to align the heights of the upper surfaces of the plurality of solder bumps. In the step of forming the laminated body, the thickness of the metal paste and the ceramic paste interposed between the upper and lower ceramic green sheets is made thinner than the central portion in the outer peripheral portion of the region to be the mounting portion in a plan view. The method for manufacturing a wiring board with solder bumps according to claim 7.

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