JP5743561B2 - Wiring board - Google Patents

Description

  The present invention relates to a wiring board for accommodating and mounting an electronic component such as a semiconductor element.

  Conventionally, wiring boards for mounting electronic components such as semiconductor elements and crystal resonators are made of metal powder metallization such as tungsten or molybdenum on the surface of an insulating substrate made of an electrically insulating material such as an aluminum oxide sintered body. The wiring conductor and terminal electrode which consist of are formed.

  Such a wiring board is usually provided with an electronic component mounting region including a wiring conductor led to the surface for connection to the electronic component. And while mounting an electronic component in the electronic component mounting area | region of such a wiring board, each electrode of an electronic component is electrically connected to each corresponding wiring conductor via electrical connection means, such as solder and a bonding wire. Thus, an electronic device is manufactured. Moreover, an electronic device seals an electronic component by joining so as to cover the electronic component with a lid made of metal, ceramics, glass, resin, or the like, or a lens barrel as necessary (see Patent Document 1). reference.). Such an electronic device is electrically connected to an external electric circuit or the like by a method such as electrically connecting a terminal electrode and an electrode of an external circuit board via a bonding material or bonding a lead terminal to the terminal electrode. I was connected.

JP2003-163297

  However, in recent years, with the miniaturization, thinning, and high precision of electronic devices, wiring boards have also been miniaturized, and terminal electrodes have also become smaller. If a lead terminal that extends in the surface direction of the main surface of the wiring board is joined to the terminal electrode, if the terminal electrode becomes smaller, if the terminal electrode is pulled and stress is applied to the terminal electrode, the lead terminal and the terminal Since the bonding strength between the terminal electrode and the insulating substrate is lower than the bonding strength with the electrode, the terminal electrode may be peeled off from the insulating substrate. Thus, when the terminal electrode is peeled off from the insulating substrate, the terminal electrode is easily peeled off from the end of the terminal electrode opposite to the extending direction of the lead terminal.

  The present invention has been devised in view of the above problems of the prior art, and an object of the present invention is to provide a wiring board that is small in size and has high bonding strength between a terminal electrode and an insulating base board.

The wiring board of the present invention includes an insulating substrate, a terminal electrode disposed on the upper surface of the insulating substrate, and a lead terminal bonded to the terminal electrode and extending in the surface direction of the insulating substrate. The end portions of the terminal electrodes are joined to a metal body extending from the inside of the insulating substrate to the upper surface of the insulating substrate, and an insulating layer is coated so as to cover from the upper surface of the insulating substrate to the end portions of the terminal electrodes. The terminal electrode is formed, and only the end portion is covered with the insulating layer .

  The wiring board of the present invention is characterized in that, in the above configuration, the metal body is larger on the lower surface side than on the upper surface side.

In the wiring board of the present invention, the lead terminal extends from the outer periphery of the insulating substrate to the outside of the insulating substrate, and the end of the terminal electrode is in contact with the outer periphery of the insulating substrate. The metal body is also disposed on the outer peripheral side of the insulating substrate of the terminal electrode and exposed on a side surface of the insulating substrate, and the lead terminal is exposed on the side surface of the insulating substrate and It is joined to the terminal electrode.

  The wiring board according to the present invention is characterized in that, in the above configuration, the metal body is disposed so as to overlap with an end of the terminal electrode opposite to the extending direction of the lead terminal in a plan view. Is.

  The wiring board according to the present invention is characterized in that, in the above configuration, a plurality of the metal bodies are arranged, and the metal bodies are connected to each other inside the insulating substrate.

  In the wiring board of the present invention, since the end of the terminal electrode is joined to a metal body extending from the inside of the insulating substrate to the top surface of the insulating substrate, stress is applied to the lead terminal so as to be pulled in the surface direction of the insulating substrate. Thus, even if a force pulled from the direction in which the lead terminal extends is applied to the terminal electrode, the metal body is caught in the insulating substrate, so that the terminal electrode can be prevented from peeling off from the end.

  In the wiring board of the present invention, in the above configuration, when the metal body is larger on the lower surface side than the upper surface side, the lower surface side of the metal body is caught on the insulating substrate even if a force that is pulled on the terminal electrode is applied. The terminal electrode is more difficult to peel off from the insulating substrate.

  In the wiring board according to the present invention, the lead terminal extends from the outer periphery of the insulating substrate to the outside of the insulating substrate, the end of the terminal electrode is disposed in contact with the outer periphery of the insulating substrate, and the metal body is the terminal. When the lead terminal is also disposed on the outer peripheral side of the insulating substrate of the electrode and exposed to the side surface of the insulating substrate, and the lead terminal is bonded to the metal body and the terminal electrode exposed on the side surface of the insulating substrate, the lead terminal Is bonded over the upper surface and the side surface of the insulating substrate, so that the bonding strength between the lead terminal and the terminal electrode can be increased.

The wiring board of the present invention having the above structure, since the insulating layer is formed so as to cover over the said end of the terminal electrode from the upper surface of the insulating substrate, even if force is present to pull the terminal electrode Since the end from which the terminal electrode is peeled off is embedded and pressed in the insulating layer, it is more effective to suppress the terminal electrode from being peeled off from the insulating substrate.

  In the wiring board of the present invention, when the metal body is arranged so as to overlap the end of the terminal electrode on the side opposite to the direction in which the lead terminal extends in the above configuration, the terminal electrode Even if a pulling force is applied, the end of the terminal electrode from which the terminal electrode peels off is bonded to the same metal body and the bonding strength is high, so it is more effective to suppress the terminal electrode from peeling off the insulating substrate. .

  In the wiring board of the present invention, in the above configuration, when a plurality of metal bodies are arranged and the metal bodies are connected to each other inside the insulating substrate, the metal bodies are applied even if a force that pulls the terminal electrode is applied. This is effective in suppressing the portion where the terminals are connected to each other from being caught on the insulating substrate and the terminal electrode from being peeled off from the insulating substrate.

(A) is a top view which shows an example of the principal part of embodiment of the wiring board of this invention, (b) is sectional drawing in the AA of (a). (A) And (b) is sectional drawing which shows the other example of embodiment of the wiring board of this invention, respectively. (A) is a top view which shows an example of embodiment of the wiring board of this invention, (b) is sectional drawing in the AA of (a). (A) is a top view which shows the other example of embodiment of the wiring board of this invention, (b) is sectional drawing in the AA of (a). (A) is a top view which shows the other example of embodiment of the wiring board of this invention, (b) is sectional drawing in the AA of (a). (A) is a top view which shows the other example of embodiment of the wiring board of this invention, (b) is sectional drawing in the AA of (a). (A) is a top view which shows the other example of embodiment of the wiring board of this invention, (b) is sectional drawing in the AA of (a). (A) And (b) is sectional drawing which shows the other example of embodiment of the wiring board of this invention, respectively.

  The wiring board of the present invention will be described with reference to the accompanying drawings. 1 to 6, 1 is an insulating substrate, 1a is an insulating layer, 2 is a terminal electrode, 2a is a metal body, 3 is a wiring conductor, 4 is a connection electrode, and 5 is a lead terminal.

  1 to 6, the wiring board of the present invention is bonded to the insulating substrate 1, the terminal electrode 2 disposed on the upper surface of the insulating substrate 1, and the terminal electrode 2. In the wiring board having the lead terminals 5 extending in the surface direction, the end of the terminal electrode 2 opposite to the direction in which the lead terminals 5 extend is the metal body 2a extending from the inside of the insulating substrate 1 to the upper surface of the insulating substrate 1. Therefore, even if a force to be pulled by the terminal electrode 2 is applied to the lead terminal 5 due to a stress that is pulled in the surface direction of the insulating substrate 1, the metal body 2 a is placed in the insulating substrate 1. Since it is caught, it can suppress that the terminal electrode 2 peels from the edge part on the opposite side to the direction where the lead terminal 5 is extended.

  Further, when the lower surface side of the metal body 2a is larger than the upper surface side as in the example shown in FIG. 2, the lower surface side of the metal body 2a remains on the insulating substrate 1 even if a force that is pulled by the terminal electrode 2 is applied. Therefore, it is more effective to reduce the peeling of the terminal electrode 2 from the insulating substrate 1.

  Further, as in the example shown in FIG. 3, the lead terminal 5 extends from the outer periphery of the insulating substrate 1 to the outside of the insulating substrate 1, and the end portion of the terminal electrode 2 is disposed in contact with the outer periphery of the insulating substrate 1. The body 2a is also disposed on the outer peripheral side of the insulating substrate 1 of the terminal electrode 2 and is exposed on the side surface of the insulating substrate 1, and the lead terminal 5 is exposed on the side surface of the insulating substrate 1 and the terminal electrode 2 In the case where the lead terminals 5 are joined to each other, the lead terminals 5 are joined across the upper surface and the side surface of the insulating substrate 1, so that the joining strength between the lead terminals 5 and the terminal electrodes 2 can be increased. The surface where the wiring conductor 3 is exposed on the side surface of the insulating substrate 1 is connected to the connection electrode 4.

  In addition, as in the example shown in FIG. 4, when the insulating layer 1 a is formed so as to cover from the upper surface of the insulating substrate 1 to the end of the terminal electrode 2, a force that pulls the terminal electrode 2 is applied. However, since the end from which the terminal electrode 2 is peeled off is embedded and pressed in the insulating layer 1a, it is more effective to suppress the terminal electrode 2 from being peeled from the insulating substrate 1.

Further, as in the example shown in FIGS. 5 and 6, when the metal body 2 a is disposed so as to overlap with the end of the terminal electrode 2 on the opposite side to the extending direction of the lead terminal 5 in plan view. Even when a force that pulls the terminal electrode 2 is applied, the end from which the terminal electrode 2 is peeled off is bonded to the same metal body 2a and the bonding strength is high. It is effective in suppressing peeling.

  In addition, as in the example shown in FIG. 7, a plurality of metal bodies 2 a are arranged, and when the metal bodies 2 a are connected to each other inside the insulating substrate 1, even if a force that pulls the terminal electrode 2 is applied, It is effective to suppress the portion where the metal bodies 2a are connected to each other from being caught on the insulating substrate 1 and peeling off the terminal electrode 2 from the insulating substrate 1.

  The insulating substrate 1 is made of an insulator such as ceramics or resin. When made of ceramics, for example, aluminum oxide sintered bodies (alumina ceramics), aluminum nitride sintered bodies, mullite sintered bodies, glass ceramic sintered bodies, and the like can be mentioned. , Fluororesins such as epoxy resin, polyimide resin, acrylic resin, phenol resin, polyester resin, and tetrafluoroethylene resin. Moreover, what impregnated resin to the base material which consists of glass fibers like glass epoxy resin is mentioned.

When the insulating substrate 1 is made of, for example, an aluminum oxide sintered body, organic materials suitable for raw material powders such as alumina (Al ₂ O ₃ ), silica (SiO ₂ ), calcia (CaO), and magnesia (MgO) are used. A ceramic green sheet is obtained by adding a solvent and a solvent to form a slurry, and forming this into a sheet using a conventionally known doctor blade method, calendar roll method, etc. Appropriate punching processing is performed on the sheet, and a plurality of sheets are laminated as necessary, and the sheet is manufactured by firing at a high temperature (about 1500 to 1800 ° C.). When the insulating substrate 1 is made of resin, for example, a predetermined wiring substrate Using a mold that can be molded into any shape, using the transfer molding method, injection molding method, etc. It can be. Further, for example, a glass fiber base material impregnated with a resin, such as glass epoxy resin, in this case, a glass fiber base material is impregnated with an epoxy resin precursor, The epoxy resin precursor can be formed by thermosetting at a predetermined temperature.

  The terminal electrode 2, the wiring conductor 3, and the connection electrode 4 are made of metal such as tungsten (W), molybdenum (Mo), manganese (Mn), silver (Ag), or copper (Cu) when the insulating substrate 1 is made of ceramics. A ceramic green sheet for insulating substrate 1, which is made of powder metallization, is printed on a ceramic green sheet for insulating substrate 1 in a predetermined shape with a conductive paste for terminal electrode 2, wiring conductor 3 or connection electrode 4 by screen printing or the like. By baking simultaneously, it forms in the predetermined position of a wiring board.

The wiring conductor 3 includes a wiring conductor disposed between the surface of the insulating substrate 1 and the insulating layers, and a through conductor that electrically connects the wiring conductors 3 positioned vertically through the insulating layer. When the insulating substrate 1 is made of ceramics, the wiring conductor disposed between the insulating layers is obtained by printing and applying a metallized paste for the wiring conductor 3 on a ceramic green sheet for the insulating substrate 1 by printing means such as a screen printing method. It is formed by firing together with a generated shape for the substrate 1. Further, the through conductor is formed for the through conductor by a processing method such as punching or laser processing using a die or punching on the ceramic green sheet for the insulating substrate 1 prior to printing and application of the metallized paste for forming the wiring conductor 3. A through hole is formed, and a metallized paste for a through conductor is filled in the through hole by a printing means such as a screen printing method, and is fired together with a generated shape to be the insulating substrate 1. The metallized paste is prepared by adding an organic binder and an organic solvent to the main component metal powder and, if necessary, a dispersing agent and the like, and mixing and kneading by a kneading means such as a ball mill, a three-roll mill or a planetary mixer. Further, glass or ceramic powder may be added to match the sintering behavior of the ceramic green sheet or to increase the bonding strength with the insulating substrate 1 after firing. The metallized paste for the through conductor is adjusted to a viscosity higher than that of the metallized paste for the wiring conductor 3, which is suitable for filling, depending on the type and amount of the organic binder or organic solvent. The metallized paste may contain glass or ceramics in order to increase the bonding strength with the insulating substrate 1.

  When the insulating substrate 1 is made of resin, the terminal electrode 2, the wiring conductor 3, and the connection electrode 4 are made of a metal material such as copper, gold, aluminum, nickel, chromium, molybdenum, titanium, and alloys thereof. For example, the copper foil processed into the shape of the terminal electrode 2 is transferred onto a resin sheet made of glass epoxy resin, and the resin sheet on which the copper foil is transferred is laminated and bonded with an adhesive. Further, among the wiring conductors 3, the through conductors that penetrate the resin sheet in the thickness direction are deposited on the inner surfaces of the through holes formed in the resin sheet by conductor paste printing or plating, or filled with the through holes. What is necessary is just to form. Further, it is formed by integrating a metal foil or a metal column by resin molding or by depositing the insulating substrate 1 using a sputtering method, a vapor deposition method, a plating method or the like.

  The terminal electrode 2 is disposed on at least one of the one main surface and the side surface of the insulating substrate 1 as in the example shown in FIGS. In particular, the terminal electrode 2 is disposed so that the end of the terminal electrode 2 is in contact with the outer periphery of the insulating substrate 1, and the metal body 2 a disposed on the outer peripheral side of the insulating substrate 1 is exposed on the side surface of the insulating substrate 1. Is preferred.

  Further, when the insulating substrate 1 is made of ceramics, for example, the insulating layer 1a is formed by using a ceramic paste made of the same material as the ceramic green sheet or the ceramic green sheet on the upper surface of the laminate in which the ceramic green sheets are laminated. Then, it may be applied or arranged so as to cover the end portion of the conductor paste to be the terminal electrode 2. When the insulating layer 1a is produced using a ceramic paste, it is not necessary to apply pressure as in the case of using a ceramic green sheet, so that the laminate is not easily deformed. Further, the insulating layer 1a can be thinned. Therefore, when the insulating layer 1a is formed using the ceramic paste, it is effective to reduce the size while suppressing the deformation of the insulating substrate 1. Further, when the insulating substrate 1 is made of, for example, a resin, for example, after applying a photocurable resin, it may be cured by irradiating with light of an appropriate wavelength. A thermosetting resin or the like may be used instead of the photocurable resin.

The metal body 2a of the terminal electrode 2 is formed in the same manner as the above-described through conductor. That is, after the through hole is formed in the ceramic green sheet, the through hole is filled with the conductive paste by printing the conductive paste in the through hole. When forming a through hole using a mold, a convex mold in which a convex shape (pin shape) is formed at a position corresponding to the through hole, and a concave mold in which a concave shape corresponding to the convex shape is formed Is arranged above and below the ceramic green sheet, and the ceramic green sheet is cut by meshing them to form a through hole. In addition, when forming a through-hole using a laser, an appropriate laser beam (carbon dioxide laser, YAG laser, etc.) is focused on the position corresponding to the through-hole and irradiated to instantaneously heat the ceramic green sheet. By doing so, a through hole can be formed. After filling the through hole formed in this way with a conductive paste substantially equivalent to the conductive paste for the terminal electrode 2, the ceramic green sheet is fired to simultaneously form the metallic body 2 a of the terminal electrode 2 with the terminal electrode 2. Can be formed. In addition, after forming the recessed part by reducing the output of the laser, the recessed part may be filled with a conductive paste. Such a method is effective when the thickness and layer configuration of the wiring board are limited. That is, rather than preparing two ceramic green sheets and forming through-holes in one sheet, and laminating these ceramic green sheets to form a recess that becomes the metal body 2a, a laser is applied to one ceramic green sheet. It is more effective to suppress the elongation of the ceramic green sheet because the thickness of the ceramic green sheet is not reduced by forming the concave portion to be the metal body 2a. Further, when the insulating substrate 1 is made of resin, after forming the insulating substrate 1 using an appropriate mold, a through hole for the metal body 2a is formed using machining such as a drill or laser processing. It doesn't matter.

  In addition, as in the example shown in FIG. 1B, the through conductor of the wiring conductor 3 connected to the terminal electrode 2 is normally connected to the center portion of the terminal electrode 2. At this time, the metal body 2a of the terminal electrode 2 is disposed at the end of the terminal electrode 2 on the side opposite to the direction in which the lead terminal 5 extends. Even if a force is applied to the terminal electrode 2 from the direction in which the lead terminal 5 extends, the metal body 2a is caught by the insulating substrate 1, so that the terminal electrode 2 is prevented from peeling off from the end opposite to the direction in which the lead terminal extends. be able to.

  Moreover, it is preferable that the metal body 2a is also arrange | positioned also at the edge part of the direction where the lead terminal 5 of the terminal electrode 2 is extended like the example shown in FIG.2 (b). Arranging the metal body 2a in this way is effective in making the terminal electrode 2 more difficult to peel off.

  2A, when the through conductor of the wiring conductor 3 connected to the terminal electrode 2 is connected to the end of the terminal electrode 2 in the direction in which the lead terminal 5 extends, The same effect as when the metal body 2a is also arranged at the end of the electrode 2 in the direction in which the lead terminal 5 extends can be obtained.

  Moreover, it is preferable that the lower surface side of the metal body 2a is larger than the upper surface side of the insulating substrate 1, as in the example shown in FIG. When the metal body 2a is gradually increased from the upper surface side to the lower surface side of the insulating substrate 1 as in the example shown in FIG. 2A, the hole for the metal body 2a is filled with the conductive paste. At this time, since there is no corner on the inner surface of the hole, the conductor paste is easily filled in the hole without any gap. Therefore, the metal paste 2a and the insulating substrate can be filled with the conductor paste well to increase the bonding area with the insulating substrate 1. It is effective to ensure the bonding strength with 1. Further, as in the example shown in FIG. 2B, when the lower surface side of the metal body 2 a is larger than the upper surface side and there is a step portion between the upper surface side and the lower surface side, the metal body 2 a is the insulating substrate 1. Therefore, it is effective in making the terminal electrode 2 difficult to peel off from the insulating substrate 1.

  For example, when the through hole for the metal body 2a is formed using a mold, the through hole having a larger size on the lower surface side than the upper surface side of the insulating substrate 1 is concave rather than the convex portion of the convex mold. It can be formed by punching out the ceramic green sheet using a mold having a larger concave portion of the mold, with the lower surface side of the ceramic green sheet being in contact with the concave mold. Moreover, when forming the through-hole for metal bodies 2a using a laser, it can form by irradiating a laser beam from the lower surface side of a ceramic green sheet. In addition, when filling such a through-hole with a conductor paste, it is preferable to fill from the lower surface side where the through-hole is formed, because the conductor paste is filled into the through-hole without a gap.

  When the metal body 2a is also arranged at the end of the terminal electrode 2 in the direction in which the lead terminal 5 extends, the terminal electrode 2 on the side in which the lead terminal 5 extends as in the example shown in FIG. Even if the metal body 2 a disposed at the end of the terminal electrode 2 on the side in which the lead terminal 5 extends is exposed to the side surface of the insulating substrate 1. Good. The metal body 2a exposed on the side surface of the insulating substrate 1 forms a dummy region around each wiring substrate region when the wiring substrate is manufactured, and penetrates the wiring substrate region and the dummy region. Can be formed by dividing the through hole along the boundary line between the wiring board region and the dummy region. When the conductor paste is applied to the inner surface of the through hole, the terminal electrode 2 exposed on the side surface can be formed in a concave shape, so that the bonding material is filled in the concave portion, and the bonding strength between the lead terminal 5 and the terminal electrode 2 is increased. Since it can improve, it is preferable.

  Further, when the metal body 2a is arranged so as to overlap with the end of the terminal electrode 2 opposite to the direction in which the lead terminal 5 extends in a plan view, the metal body 2a has a shape as shown in FIG. The upper surface and the end of the terminal electrode 2 may be overlapped so that the metal body 2a is exposed on the upper surface of the insulating substrate 1, or the end of the metal body 2a and the terminal may be disposed as in the example shown in FIG. You may arrange | position so that the edge of the electrode 2 may be aligned and the edge of the metal body 2a and the edge of the terminal electrode 2 may overlap in planar view.

  As shown in the example shown in FIG. 7, a plurality of metal bodies 2 a are arranged at the end of the terminal electrode 2, and when the metal bodies 2 a are connected to each other inside the insulating substrate 1, for example, FIG. As shown in the example, a plurality of metal bodies 2a whose lower surface side is larger than the upper surface side may be formed so that the lower surface sides of the metal bodies 2a are connected to each other. Further, the connected portion of the metal body 2a may be in the middle of the insulating substrate 1 in the thickness direction. However, if the metal body 2a is on the lower end side of the metal body 2a, the metal body 2a can be seen in cross-section as in the example shown in FIG. It is preferable because the region of the insulating substrate 1 surrounded by the body 2a becomes large, and the insulating substrate 1 in this portion can be prevented from being destroyed. More preferably, the lower ends of the metal bodies 2a may be joined to each other as in the example shown in FIG.

  When the insulating substrate 1 is made of ceramics, such a portion connecting the metal bodies 2a is printed with a metallized paste similar to that used for the wiring conductor 3 on the insulating layer between the lower ends of the metal bodies 2a. What is necessary is just to apply and produce. Moreover, you may join between the lower ends of the metal body 2a with the penetration conductor formed by the method similar to the above-mentioned penetration conductor 3. FIG.

  Even when the metal body 2a and the wiring conductor 3 electrically connected to the terminal electrode 2 joined to the metal body 2a are connected inside the insulating substrate 1 as in the example shown in FIG. The same effect as the example shown in FIG. Moreover, since it is not necessary to arrange a plurality of metal bodies 2a, it is effective for reducing the size of the wiring board.

  In addition, when arrange | positioning the some metal body 2a, at least one of the some metal body 2a should just be arrange | positioned at the edge part of the terminal electrode 2 like the example shown in FIG.

  When the insulating substrate 1 of the wiring substrate is made of ceramics, the upper surface of the metal body 2a may be concave or convex during firing. When the upper surface of the metal body 2a is concave, the bonding strength between the terminal electrode 2 and the metal body 2a may be reduced. In particular, when the metal body 2 a has an exposed surface exposed on the upper surface of the insulating substrate 1, the metal body 2 a is easily peeled off from the end of the terminal electrode 2 that is the starting point of the peeling. Therefore, if the upper surface of the metal body 2a is convex, the metal body 2a is bonded to the terminal electrode 2 even at the center side of the exposed surface, so that it is effective to suppress a decrease in bonding strength. . In order to make the exposed surface convex, the amount of metal particles, organic binder, and organic solvent of the metallized paste that becomes the wiring conductor 3 is adjusted, and a metallized paste that is harder to shrink than the ceramic that becomes the insulating substrate 1 during firing is prepared. Use it.

  Further, when the wiring board is made of a so-called multi-piece substrate, a dividing groove is formed so as to divide the through hole for forming the metal body 2a exposed on the side surface of the divided insulating substrate 1, When the conductive paste is adjusted so as to be more easily contracted than the ceramic green sheet, the metal body 2a exposed on the side surface of the insulating substrate 1 after firing can be formed in a concave shape. In such a method, particularly when the width of the metal body 2a exposed on the side surface is narrow, it is difficult to apply the conductor paste to the inner surface of the through hole, and the metal body 2a exposed on the side surface of the insulating substrate 1 is difficult. It is effective when it is difficult to form a concave shape.

The connection electrode 4 is formed on the side surface of the insulating substrate 1 as in the examples shown in FIGS. 1 to 6 and is for mounting electronic components. Such a connection electrode 4 is electrically connected to the wiring conductor 3. When the side surface of the insulating substrate 1 and the connection electrode 4 are formed flush with each other as in the example shown in FIGS. 1 to 6, if the insulating substrate 1 is made of ceramics, the wiring substrate is removed from the mother substrate. At the time of cutting, if cut by dicing, the cut surface becomes flat. In the example shown in FIGS. 1 to 6, the side surface of the insulating substrate 1 and the connection electrode 4 are formed flush with each other, but the connection electrode 4 forms a concave portion on the side surface of the insulating substrate 1. It may be formed on the inner surface. It is preferable to form the connection electrode 4 in the recess since the bonding material for bonding the electronic component to the connection electrode 4 is filled in the recess and the bonding strength between the lead terminal 5 and the terminal electrode 2 can be improved. Such a recess may be formed by cutting a part of the side surface of the insulating substrate 1 in the thickness direction of the insulating substrate 1 or may be formed in a groove shape so as to penetrate in the thickness direction of the insulating substrate 1. Good.

In addition, the metal which is excellent in corrosion resistance, such as nickel and gold | metal | money, is adhere | attached on the exposed surface of the terminal electrode 2 and the connection electrode 4 as needed. Accordingly, corrosion of the terminal electrode 2 and the connection electrode 4 can be effectively suppressed, and the bonding between the terminal electrode 2 and the lead terminal 5 and the connection between the terminal electrode 2 and the wiring conductor 3 of the external electric circuit board can be performed. The bonding between the bonding and connection electrode 4 and the electrode of the electronic component to be mounted or the bonding wire can be strengthened. Further, for example, the exposed surface of the wiring conductor 3 is successively covered with a nickel plating layer having a thickness of about 1 μm to 10 μm and a gold plating layer having a thickness of about 0.1 μm to 3 μm by an electrolytic plating method or an electroless plating method. Worn.

  The lead terminal 5 is bonded to the metal body 2 a exposed on the side surface of the insulating substrate 1 and the terminal electrode 2 to electrically connect the external electric circuit and the wiring conductor 3.

The lead terminal 5 is made of a metal such as an Fe—Ni—Co alloy, Fe—Ni alloy, copper (Cu), or copper alloy. From the viewpoint of the connection reliability of the lead terminal 5 with the insulating substrate 1, it is preferable that the difference between the thermal expansion coefficient of the insulating substrate 1 is small and the insulating substrate 1 is made of an aluminum oxide sintered body. In this case, for example, an Fe0.58-Ni0.42 alloy containing 58% iron (Fe) and 42% nickel (Ni) is preferable. A nickel plating layer and a gold plating layer are provided on the surface of the lead terminal 5 in order to prevent corrosion, improve conductivity, improve the wettability of the connecting member, and reduce the connection resistance with the terminal electrode 2. It is good to deposit sequentially.

The connection member for connecting the lead terminal 5 and the terminal electrode 2 is, for example, an Au0.8-Sn0.2 eutectic alloy containing 80% by mass of gold (Au) and 20% by mass of tin (Sn), Au type such as Au0.88-Ge0.12 eutectic alloy containing 88% by mass of gold and 12% by mass of germanium (Ge), or Ag0 containing 72% by mass of silver (Ag) and 28% by mass of copper. Ag0.55-Cu0.22-Zn0.17-Sn0.05 containing 72-Cu0.28 alloy and 55 mass% silver, 22 mass% copper, 17 mass% zinc (Zn) and 5 mass% tin It is a brazing material made of an AgCu alloy such as an alloy. For example, when using an Au0.8-Sn0.2 eutectic alloy, a ribbon of Au0.8-Sn0.2 eutectic alloy is placed on the terminal electrode 2 of the insulating substrate 1, and the lead terminal 5 is placed thereon. The lead terminal 5 can be connected to the terminal electrode 2 by mounting the tip of the lead and fixing it with a jig and heating it at a peak temperature of 350 ° C. in a reducing atmosphere.

  In addition, when the electrical connection with the terminal electrode 2 is performed using an FPC (flexible printed circuit board) in which a plurality of lead terminals 5 are bundled and integrated, the plurality of lead terminals 5 and the terminal electrode 2 can be connected simultaneously. Therefore, it is preferable.

Also, the gold in the connection member after connection is adjusted by adjusting the amount of Au0.8-Sn0.2 eutectic alloy containing 80% gold and 20% tin and the gold plating thickness of the surface of the terminal electrode 2 By increasing the content rate, the melting point of the connecting member can be raised above 280 ° C., which is the melting point of the eutectic alloy. For example, when the gold plating thickness on the surface of the terminal electrode 2 is adjusted so that the gold content in the connection member after connection is 90 mass%, the melting point of the connection member after connection is about 400 ° C. For higher heat resistance, an Ag0.72-Cu0.28 alloy having a melting point of 780 ° C, or Ag0.
55-Cu0.22-Zn0.17-Sn0.05 may be used as the connecting member.

  As in the example shown in FIG. 1, the electronic component is mounted in a mounting region in which the connection electrode 4 on the side surface of the insulating substrate 1 is disposed.

  For example, when the electronic component is a flip-chip type image pickup device 7, the electrode of the electronic component and the connection electrode are connected via a connection member such as a solder bump, a gold bump, or a conductive resin (anisotropic conductive resin or the like). 4 are connected by electrical and mechanical connection. In this case, underfill may be injected between the image sensor 7 and the mounting region 2 after connecting via bumps that are connecting members. In either case, a small electronic component such as a resistor element or a capacitor element may be mounted on the wiring board as necessary.

  Note that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

  For example, as in the example shown in FIG. 3, when the metal body 2 a is substantially semicircular in plan view, the center of the metal body 2 a exposed on the side surface is closer to the insulating substrate 1 than the outer peripheral side of the insulating substrate 1. You may be biased to. In such a case, the width of the metal body 2a exposed on the side surface is narrower than the diameter of the semicircle of the metal body 2a in the side view, so that even if the metal body 2a is pulled in the side surface direction of the insulating substrate 1, It is preferable because it can be prevented from being caught by the insulating substrate 1 and peeling in the side surface direction. Further, a concave portion may be formed on the main surface or side surface of the insulating substrate 1 and a small electronic component such as a capacitor or a resistor may be mounted.

DESCRIPTION OF SYMBOLS 1 ... Insulating substrate 1a ... Insulating layer 2 ... Terminal electrode 2a ... Metal body 3 ... Wiring conductor 4 ... Connection electrode 5 ... Lead terminal

Claims (5)

In a wiring board comprising: an insulating substrate; a terminal electrode disposed on the upper surface of the insulating substrate; and a lead terminal bonded to the terminal electrode and extending in the surface direction of the insulating substrate.
The end portion of the terminal electrode is bonded to a metal body from the inside of the insulating substrate to the upper surface of the insulating substrate ,
An insulating layer is formed so as to cover from the upper surface of the insulating substrate to the end portion of the terminal electrode, and the terminal electrode has only the end portion covered with the insulating layer .   The wiring board according to claim 1, wherein the lower surface side of the metal body is larger than the upper surface side. The lead terminal extends from the outer periphery of the insulating substrate to the outside of the insulating substrate, the end of the terminal electrode is disposed in contact with the outer periphery of the insulating substrate, and the metal body is the insulating substrate of the terminal electrode. And is also exposed on the side surface of the insulating substrate.
The wiring board according to claim 1, wherein the lead terminal is bonded to the metal body exposed on a side surface of the insulating substrate and the terminal electrode. The metal body, according to any one of claims 1 to 3, characterized in that it is arranged to overlap the end in a plan view of the terminal electrodes on the side opposite to the direction of extension of the lead terminal Wiring board. The metal bodies are more disposed, the wiring board according to any one of claims 1 to 4, characterized in that the metal bodies inside said insulating substrate are connected.

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