JP6936774B2 - Wiring board and its manufacturing method - Google Patents

Description

In the present invention, an electrode pad for mounting an electronic component provided on the surface of a substrate body made of an insulating material, an external connection terminal provided on the back surface of the substrate body, and between the electrode pad and the external connection terminal. The present invention relates to a wiring board having a through conductor to be connected and having excellent mountability and heat dissipation, and a method for manufacturing the same.

For example, a pair of connecting electrodes having a surface overlapping a pair of mounting portions located on one main surface of the insulating substrate are embedded in the insulating substrate except for the surface and formed on the other main surface of the insulating substrate. The side surfaces of the pair of connection electrodes are electrically connected to each other in the insulating substrate, and the distance between the side surfaces is larger than that of one main surface. A substrate for mounting a semiconductor element having a larger inclination or curvature has been proposed (see, for example, Patent Document 1).
According to the semiconductor element mounting substrate, since the pair of connection electrodes are embedded in the insulating substrate except for the surface (mounting portion), heat generated from the semiconductor element mounted above the mounting portion is generated. The heat dissipation property of the above can be improved, and the occurrence of cracks or the like in the insulating substrate can be suppressed.

However, when a mounting portion having a large area is formed by electrolytic metal plating in order to mount a semiconductor element like the pair of connecting electrodes, the mounting portion is recessed toward the insulating substrate on the center side of the surface to be the mounting surface. When a recess is formed, the electrical connection with the semiconductor element to be mounted may become unstable. Further, even when a relatively large-diameter via conductor (through-hole conductor) penetrating between the pair of main surfaces of the insulating substrate is formed by electrolytic metal plating, the same applies to the center side of both end surfaces of the via conductor. Recesses are likely to occur.
Further, when the pair of connection electrodes are embedded in the insulating substrate except for their surfaces, there is a problem that the thickness of the insulating substrate may become excessively thick.

Japanese Unexamined Patent Publication No. 2015-50259 (pages 1 to 11, FIGS. 1 to 4)

The present invention solves the problems described in the background art, does not increase the thickness of the entire wiring board, has an electrode pad having excellent mountability on the surface of the substrate body made of an insulating material, and provides the substrate body. An object of the present invention is to provide a wiring board having excellent heat dissipation by means of a penetrating conductor and an external connection terminal provided on the back surface side, and a method for manufacturing the same.

Means for Solving Problems and Effects of Invention

In order to solve the above problems, the present invention solves the above problems by forming a through conductor penetrating a substrate body by electrolytic metal plating, between the electrode pads on the front surface side and the external connection terminals on the back surface side formed on both end sides thereof. It was conceived to make a certain relationship between the area in the plan view and the area and depth of the recesses formed on their surfaces.
That is, the wiring board (claim 1) of the present invention is made of an insulating material and has a front surface and a back surface facing each other, a through hole penetrating between the front surface and the back surface of the substrate body, and the penetration. A through conductor formed in the hole, an electrode pad formed at a position surrounding the opening of the through hole on the surface of the substrate body, and a position surrounding the opening of the through hole on the back surface of the substrate body. The area of the electrode pad is smaller than the area of the external connection terminal in a plan view, and the thickness of the electrode pad is the thickness of the external connection terminal. In addition to being larger than, recesses are individually formed on the surfaces of the electrode pad and the external connection terminal, and the depth of the recess located on the surface of the electrode pad is set on the surface of the external connection terminal. It is characterized by being shallower than the depth of the recess in which it is located.

According to the wiring board, the following effects (1) to (4) can be obtained.
(1) the electrode pad, reduce the area in plan view than the area of the external connection terminals, and since the thickness of the Pas head larger than the thickness of the external connection terminals, during the electrolytic metal plating at the time of manufacture The depth of the recess formed on the surface of the electrode pad and located on the surface of the electrode pad is shallower than the depth of the recess located on the surface of the external connection terminal. Therefore, since the flatness on the surface of the electrode pad can be improved, it becomes possible to electrically satisfactorily mount the electronic component on the surface above the surface via solder.
(2) The external connection terminal is formed at the time of electrolytic metal plating at the time of manufacturing because the area in a plan view is larger than the area of the electrode pad and the thickness thereof is smaller than the thickness of the electrode pad. The depth of the recess located on the surface of the external connection terminal is deeper than the depth of the recess located on the surface of the electrode pad. As a result, when the wiring board itself is mounted on a motherboard such as a printed circuit board, the surface of the external connection terminal has a large area due to the recesses, so that the contact area with the solder for joining can be increased. Therefore, this wiring board can be firmly mounted on a printed circuit board or the like.
(3) Since the thickness of the electrode pad is increased and the thickness of the external connection terminal is reduced, it is possible to suppress an increase in the thickness of the entire wiring board including these and the substrate main body.
(4) The heat generated from the electronic component mounted on the surface of the electrode pad is transferred to the electrode pad having a large thickness, the through conductor adjacent to the electrode pad, and the external connection terminal adjacent to the through conductor. It is possible to quickly and effectively dissipate heat from the insulating material side inside the substrate body and the back surface side of the substrate body to the outside.

The insulating material is composed of a single-layer or a plurality of layers of a ceramic layer or a resin layer, or a laminate of a ceramic layer and a resin layer. In the form of a plurality of ceramic layers, resin layers, or the laminated body, inner layer wiring may be formed between these layers, and a part of the inner layer wiring may be formed on the inner wall surface of the through hole with the through conductor. It may be connected.
Further, the cross-sectional shape in the direction orthogonal to the axial direction of the through hole and the shape of the electrode pad and the external connection terminal in a plan view are circular, rectangular (square or rectangular), or the like.
Further, the electrode pad, the external connection terminal, and the through conductor are mainly made of copper or silver, and a plurality of all of them are formed in the substrate main body.
Further, the recess has a circular shape in a plan view and an arc shape in a side view.
In addition, examples of electronic components mounted on the surface of the electrode pad include a light emitting diode (hereinafter, simply abbreviated as LED) and a power semiconductor.

The present invention also includes a wiring board (claim 2) in which the area of the recess located on the surface of the electrode pad is smaller than the area of the recess located on the surface of the external connection terminal in a plan view. ..
According to this, the area of the recess located on the surface of the electrode pad is smaller than the area of the recess located on the surface of the external connection terminal, and the depth of the recess is as described above. Since it is shallower than the depth of the recess on the external connection terminal side, the flatness on the surface of the electrode pad is ensured, so that the effect (1) can be obtained more reliably.

Further, in the present invention, the through conductor, the electrode pad, and the external connection terminal are made of an integral metal or different metal parts from each other, that is, a wiring board (claim 3). Is also included.
Among the above, according to the form in which the through conductor, the electrode pad, and the external connection terminal are made of an integral metal, the effect (4) can be remarkably obtained.
When the through conductor, the electrode pad, and the external connection terminal are made of one piece of copper or silver (metal), the through conductor also serves as a via conductor for energization and a heat radiation via. ..
Further, in the above-mentioned form, when the through conductor, the electrode pad, and the external connection terminal are formed of different metal parts, the thermal conductivity, the thermal expansion rate, and the like are set for each part. The through conductor, the electrode pad, and the external connection terminal can be formed in consideration of the characteristics of the metal.

In addition, in the present invention, between the inner wall surface of the through hole and the outer peripheral surface of the through conductor, between the surface of the substrate body and the bottom surface of the electrode pad, and between the back surface of the substrate body and the outside. A wiring board (claim 4) in which a metallized layer is formed is also included between the bottom surface of the connection terminal and the bottom surface of the connection terminal.
According to this, in the electrolytic metal plating at the time of manufacturing the main wiring board, the through conductor, the electrode pad, and the external connection terminal can be integrally formed of a dense metal, so that the effect (4) is more reliable. It becomes possible to obtain.
When the insulating material or the insulating plate is a high-temperature simultaneous firing ceramic such as alumina, the metallized layer and the inner layer wiring are either tungsten (hereinafter, simply abbreviated as W) or molybdenum (hereinafter, simply abbreviated as Mo). In the case of glass-ceramic or resin, it is composed of copper (Cu) or silver (Ag).

On the other hand, manufacturing method of the wiring substrate according to the present invention (claim 5) is made of insulation material, and faces the substrate main body having a front surface and a back surface to a through hole penetrating between the surface and the back surface of the substrate body The through conductor formed in the through hole, the electrode pad formed at a position surrounding the opening of the through hole on the surface of the substrate body, and the opening of the through hole on the back surface of the substrate body. A method of manufacturing a wiring board including an external connection terminal formed at a surrounding position, in which an insulating plate having an opposing front surface and a back surface is punched or laser processed to penetrate between the front surface and the back surface. Metallize the steps of forming the through hole to form the through hole, the inner wall surface of the through hole of the insulating plate, and the positions surrounding the openings on both ends of the through hole on the front surface and the back surface of the insulating plate. A step of forming a metallized layer for forming a layer, a resist layer arranged on the front surface and the back surface of the insulating plate and having a space surrounding each opening of the through hole, and a resist forming a back surface side resist layer. and formation of the layer process, the inner surface of the cylindrical metallized layer formed on the inner wall surface of the through-hole, the surface-side resist layer and the back-side resist layer front side metallization layer you position the bottom surface of the in each space And the upper surface of the back surface side metallized layer is simultaneously subjected to electrolytic metal plating to form the through conductor, the electrode pad, and the external connection terminal, and the plating step includes the electrode pad and the electrode pad. The external connection terminal is characterized in that the depth of the recess located on the surface of the electrode pad is formed to be shallower than the depth of the recess located on the surface of the external connection terminal.

According to the method for manufacturing a wiring board, the following effects (5) and (6) can be obtained.
(5) Since the resist layer forming step and the plating step are combined, the depth of the recess located on the surface of the electrode pad is shallower than the depth of the recess located on the surface of the external connection terminal. The wiring board can be reliably manufactured.
(6) In addition to the effects (1) to (4), the wiring board capable of further exerting the effect (5) can be reliably manufactured.

The insulating plate is composed of a single-layer or multi-layer green sheet, a ceramic layer obtained by firing the insulating plate, a single-layer or multi-layer resin layer, or a composite laminate of a ceramic layer and a resin layer.
Further, the resist layer may be formed by a method of forming a resin layer by applying a photosensitive resin or a method of attaching a photosensitive resin film.
Further, the thickness of the front surface side resist layer is made larger than the thickness of the back surface side resist layer, and the thickness of both is linked to the thickness of the electrode pad and the external connection terminal.
Further, as the electrolytic metal plating, the electrolytic copper plating or the electrolytic silver plating is mainly used.
In addition, the method for manufacturing the wiring board may be performed in the form of a large number of pieces.

Further, in the present invention, in the step of forming the resist layer, the area of the space in the plan view of the front surface side resist layer is smaller than the area of the space in the plan view of the back surface side resist layer. The manufacturing method (claim 6) is also included.
According to this, in the plating step, the area of the electrode pad formed in the space in the front surface side resist layer in a plan view is changed to the external connection formed in the space in the back surface side resist layer. Since the area can be made smaller than the area of the terminals, the effect (6) can be obtained in relation to the fact that the wiring board that exhibits the effect (2) can be manufactured more reliably.

Further, in the present invention, in the step of forming the resist layer, a flat resist layer made of a photosensitive resin is individually formed on the front surface and the back surface of the insulating plate in which the through holes are formed, and then the resist layer is formed. A method for manufacturing a wiring board (claim 7) is also included, in which the two resist layers are individually exposed to different areas in a plan view.
According to this, since the area of the electrode pad in a plan view can be made smaller than the area of the external connection terminal, the effect (6) can be obtained with respect to the fact that the wiring board exhibiting the effect (2) can be manufactured more reliably. It becomes possible to obtain.

In addition, the present invention comprises a method for manufacturing a wiring substrate, which comprises an etching step of etching the front surface side resist layer and the back surface side resist layer and peeling from the insulating plate after the plating step (claim 8). Is also included.
According to this, the effect (6) can be obtained more reliably.
For the etching, for example, an etching agent such as an aqueous solution of NaOH is used.
Further, after the etching step, the surface of the electrode pad and the external connection terminal exposed to the outside is coated with an ultrathin gold layer via a nickel layer.

(A) is a vertical cross-sectional view showing one form of a wiring board according to the present invention, and (B) is a partially enlarged view in (A). (A) is a plan view of the wiring board, and (B) is a bottom view of the wiring board. (A) to (H) are schematic views which show the manufacturing process for obtaining the said wiring board. (A) to (F) are schematic views showing a manufacturing process following FIG. 3 (H).

Hereinafter, embodiments for carrying out the present invention will be described.
FIG. 1 (A) is a vertical cross-sectional view showing one form of the wiring board 1 according to the present invention, and FIG. 1 (B) is a partially enlarged view of the above (A).
As shown in FIG. 1A, the wiring board 1 is formed by laminating a plurality of ceramic layers (insulating materials) c1 and c2, and has a substrate main body 2 having a front surface 3 and a back surface 4 facing each other, and the substrate main body. A pair of through holes 5 penetrating between the front surface 3 and the back surface 4 of 2, a pair of through conductors 10 formed inside each of the through holes 5, and the through holes 5 on the surface 3 of the substrate main body 2. A pair of electrode pads 12 formed at a position surrounding each opening and a pair of external connection terminals 13 formed at a position surrounding each opening of each through hole 5 on the back surface 4 of the substrate main body 2 are provided. ing.
The front surface 3 and the back surface 4 of the substrate body 2 have a rectangular (square or rectangular) shape in a plan view.
Further, the through hole 5, the through conductor 10, the electrode pad 12, and the external connection terminal 13 may be formed in a form in which two or more pairs are formed along the front-rear direction of FIG. 1 (A).

The ceramic layers c1 and c2 are made of, for example, alumina, and the thickness of the substrate body 2 composed of these is, for example, about 400 μm.
Further, the through hole 5 has a circular cross section in the radial direction, and the inner diameter thereof is, for example, about 200 μm.
Further, as shown in FIGS. 2 (A) and 2 (B), the electrode pad 12 and the external connection terminal 13 are both rectangular in plan view, and are shown in FIGS. 1 (B) and 2 (A). As shown in (B), in a plan view, the area A1 of the electrode pad 12 is smaller than the area A2 of the external connection terminal 13, while the thickness t1 of the electrode pad 12 is about 150 μm and is externally connected. It is larger than about 50 μm of the thickness t2 of the terminal 13.
In addition, the through conductor 5, the electrode pad 12, and the external connection terminal 13 are all made of copper (metal) and are formed as an integral body as shown in the drawing.

As shown in FIGS. 1 (A) and 1 (B) and FIGS. 2 (A) and 2 (B), the central side of the surface (upper surface in the drawing) of the electrode pad 12 has a circular plan view and a side view. The concave portion 14 having a shallow arc shape is located, and the concave portion 14 having a circular shape in a plan view and a depth d2 in a side view is also located on the central side of the surface (lower surface in the drawing) of the external connection terminal 13. An arc-shaped recess 15 deeper than the depth d1 is located.
Further, as shown in FIGS. 1 and 2, the area a1 of the recess 14 on the electrode pad 12 side is smaller than the area a2 of the recess 15 on the external connection terminal 13 side in a plan view, and the recess 14 is the recess. The depth d1 of 14 is shallower than the depth d2 of the recess 15. The depths d1 and d2 are the deepest portions of the recesses 14 and 15.

As shown in FIGS. 1A and 1B, a cylindrical metallized layer 6 having a cylindrical shape is formed between the inner wall surface of the through hole 5 and the outer peripheral surface of the through conductor 10. A plate-shaped surface-side metallized layer 7 that matches the shape of the electrode pad 12 is formed between the surface 3 of the substrate body 2 and the bottom surface of the electrode pad 12, and the back surface of the substrate body 2. A plate-shaped back surface side metallize layer 8 that matches the shape of the external connection terminal 13 is formed between 4 and the bottom surface (upper surface in the drawing) of the external connection terminal 13.
The metallized layers 6 to 8 are made of W or Mo having a thickness of several tens of μm, and are electrically connected to each other, for example.
Further, between the ceramic layers c1 and c2 constituting the substrate main body 2, an inner layer wiring 9 is formed of W or Mo, has a required pattern in a plan view, and has the same thickness as described above, and a part of the inner layer wiring 9 is cylindrical. It is connected to the cylindrical metallize layer 6 having a shape.

In the wiring substrate 1 having the above-described form, the electrode pad 12 has an area A1 in a plan view smaller than the area A2 of the external connection terminal 13, and the thickness t1 of the electrode pad 12 is the external connection terminal 13. Since it is larger than the thickness t2, the depth d1 of the recess 14 formed at the time of electrolytic metal plating at the time of manufacturing and located on the surface of the electrode pad 12 is changed to the depth d1 of the recess 15 located on the surface of the external connection terminal 13. It is formed shallower than d2. Therefore, as shown in FIG. 1A, the electronic component 16 such as the LED is electrically mounted above the surface of each of the electrode pads 12 with improved flatness via solder (not shown). It is possible to connect and implement well.

Further, since the area A2 of the external connection terminal 13 in a plan view is larger than the area A1 of the electrode pad 12 and the thickness t2 thereof is smaller than the thickness t1 of the electrode pad 12, the electrolytic metal plating at the time of manufacture is used. The depth d2 of the recess 15 located on the surface of the external connection terminal 13 is formed deeper than the depth d1 of the recess 14 located on the surface of the electrode pad 12. Therefore, as shown in FIG. 1A, when the main wiring board 1 is mounted on the surface of the printed circuit board 17, the surface of the external connection terminal 13 has a large area due to the recess 15 for joining. Since the contact area with solder (not shown) can be increased, robust mounting is possible.

Further, since the thickness t1 of the electrode pad 12 is thickened and the thickness t2 of the external connection terminal 13 is thinned, the thickness of the entire wiring board 1 including these and the board body 2 is excessively increased. Can be easily suppressed.
In addition, the heat generated from the electronic component 16 such as the LED mounted on the surface of the electrode pad 12 is transferred to the electrode pad 12 having a large thickness, the through conductor 10 continuous with the electrode pad 12, and the penetration. It is possible to quickly and effectively dissipate heat from the inside of the ceramic layers c1 and c2 inside the substrate body 2 and the back surface 4 side of the substrate body 1 via the external connection terminal 13 continuous with the conductor 10. Become.
Therefore, according to the wiring board 1, the effects (1) to (4) can be surely obtained.

Hereinafter, a method for manufacturing the wiring board 1 will be described.
A ceramic slurry (not shown) is prepared in advance by blending an appropriate amount of alumina powder, binder resin, plasticizer, solvent, etc., and the slurry is prepared by the doctor blade method as shown in FIG. 3 (A). Two layers of green sheets (insulating plates) g1 and g2 having a thickness of more than about 200 μm were prepared.
Next, punching processing with a punch and a die or laser processing by laser irradiation is performed on each appropriate place of the green sheet g1 and g2, and as shown in FIG. 3B, the green sheet g1 and g2 Through holes 5a and 5b were formed so as to individually penetrate between the front surface and the back surface and have an inner diameter of about 200 μm.

Next, a conductive paste containing W powder or Mo powder is screen-printed at predetermined positions on at least one of the front surface and the back surface of the green sheets g1 and g2, and as shown in FIG. 3 (C). The plan view is rectangular with respect to the position surrounding the opening of the through hole 5a on the surface of the green sheet g1 on the upper layer side and the position surrounding the opening of the through hole 5b on the front surface and the back surface of the green sheet g2 on the lower layer side. An unfired front surface side metallized layer 7 and a back surface side metallized layer 8 exhibiting a shape, and an unfired inner layer wiring 9 exhibiting a pattern required in a plan view were formed. The unfired inner layer wiring 9 was formed at the same time as the above even at a position (not shown) on the surface of the green sheet g2.
Further, as shown in FIG. 3D, the same conductive paste as described above is applied to each of the inner wall surfaces of the through holes 5a and 5b of the green sheets g1 and g2 under a state of utilizing negative pressure. Formed unfired metallized layers 6a and 6b having a cylindrical shape.
The thickness of the metallized layers 6 to 8 and the inner layer wiring 9 was about 20 μm.

Next, the green sheets g1 and g2 on which the metallized layers 6 to 8 and the inner layer wiring 9 were formed were laminated and crimped so that the through holes 5a and 5b communicate with each other by a coaxial center.
As a result, as shown in FIG. 3 (E), the green sheets g1 and g2 are laminated, the through holes 5a and 5b are coaxially communicated, and the metallized layers 6a and 6b are connected so as to be continuous. A green sheet laminate 18 containing a tubular metallized layer 6 was obtained.
Next, the green sheet laminate 18 was heated and further held by firing.
As a result, as shown in FIG. 3 (F), the green sheets g1 and g2 become ceramic layers (insulating materials) c1 and c2 and become the substrate main body 2 integrated with each other, and at the same time, the metallized layers 6 to 6 to 8 and the inner layer wiring 9 were also fired, and they were connected to each other.

Further, as shown in FIG. 3 (G), a surface-side resist layer 20 having a thickness of about 150 μm is formed on the entire surface of the surface 3 of the substrate body 2, and the entire surface of the back surface 4 of the substrate body 2 is formed. , A back surface side resist layer 22 having a thickness of about 50 μm was formed. The resist layers 20 and 22 were formed by, for example, attaching a film made of a photosensitive resin such as an epoxy type.
Next, ultraviolet rays are individually exposed to the resist layers 20 and 22 in a rectangular pattern having a different area for each position including the openings at both ends in the through hole 5, and then known etching is performed on each exposed portion. The liquids were brought into contact individually.

As a result, as shown in FIG. 4A, the surface side resist layer 20 has the opening at the position surrounding the opening of the through hole 5 on the center side, and the area in a plan view is A1. A cylindrical space 21 was formed. At the same time, a cylindrical space having the opening on the center side and having an area A2 in a plan view larger and thinner than the area A1 at a position surrounding the opening of the through hole 5 in the back surface side resist layer 22. 23 was formed. The area A1 corresponds to the area A1 of the electrode pad 12 in the plan view, and the area A2 corresponds to the area A2 of the external connection terminal 13 in the plan view. As shown in the figure, the spaces 21 and 23 communicate with each other through the through holes 5.
Further, the metallizing layer located on the inner side surface of the tubular metallizing layer 6 formed on the inner wall surface of the through hole 5 and the bottom surface in the spaces 21 and 23 of the front surface side resist layer 20 and the back surface side resist layer 22. A plating step was performed in which electrolytic copper (metal) plating was simultaneously applied to the upper surfaces of each of 7 and 8.

Specifically, the tubular metallized layer in a state where the substrate main body 2 having the resist layers 20 and 22 and the spaces 21 and 23 shown in FIG. 4A is immersed in an electrolytic copper plating bath (not shown). 6 and the metallized layers 7 and 8 were on the cathode side, and a predetermined plating current was applied between the metallized layers 7 and 8 and the opposing anodes (not shown). At this time, the inner layer wiring 9 was used as the plating wiring.
In the electrolytic copper plating bath, copper ions (Cu ²⁺ ) eluted from the anode into the plating bath with respect to the inner surface of the tubular metallize layer 6 and the upper surfaces of the metallize layers 7 and 8. It was sequentially deposited and deposited. As a result, as shown in FIG. 4B, it is along the inner side surface of the tubular metallize layer 6, and is entirely along the cylindrical copper-plated portion 10a and the upper surfaces of the metallize layers 7 and 8. , Copper-plated portions 12a and 13a having a ring shape in a plan view were formed.

Subsequently, as a result of continuing the electrolytic copper plating, as shown in FIG. 4C, the cylindrical copper-plated portion 10a further grows to fill the inside of the through hole 5 and becomes the through conductor 10. became. In parallel, the copper-plated portions 12a and 13a on the upper surfaces of the metallized layers 7 and 8 grow into thickened copper-plated portions 12b and 13b, respectively, and each center side on these surfaces has a central portion. Conical recesses 14a and 15a with recesses were individually formed.
Further, as a result of continuing the electrolytic copper plating, as shown in FIG. 4D, the copper-plated portions 12b and 13b grow along the thickness direction in each of the spaces 21 and 23. At the same time, conical recesses 14b and 15b having a shallowly recessed central portion were individually formed on each central side of these surfaces.

Then, in the electrolytic copper plating as described above, as shown in FIG. 4 (E), the copper plating portion 12b becomes an electrode pad 12 that fills the entire space 21 of the surface side resist layer 20, and the copper plating is performed. It ended when the portion 13b became the external connection terminal 13 that filled the entire space 23 of the back surface side resist layer 22.
At this time, as shown in the drawing, on the central side of the surface of the electrode pad 12, a concave portion 14 having a small diameter in a plan view and a shallow arc shape, which is a trace of the concave portion 14b, was formed. On the other hand, on the central side of the surface of the external connection terminal 13, a concave portion 15 having an arc shape, which is a trace of the concave portion 15b and has a large diameter in a plan view and is deeper than the concave portion 14, is formed.

Further, an etching step was performed in which the front surface side resist layer 20 and the back surface side resist layer 22 were etched with, for example, an etching agent composed of an aqueous solution of NaOH to be peeled off from the front surface 3 and the back surface 4 of the substrate body 2. ..
Finally, in the substrate main body 2, electrolytic nickel plating and electrolytic gold plating are sequentially applied to the surfaces of the electrode pad 12 and the external connection terminal 13 exposed to the outside, and the surface is made ultra-thin through the underlying nickel layer. The gold layers were individually coated.
As a result, as shown in FIG. 4 (F), the wiring board 1 having the same form as that shown in FIG. 1 (B) could be obtained.
In addition, each of the above steps may be performed in the form of taking a large number of wiring boards 1 in order to manufacture the plurality of wiring boards 1 at the same time.

Since the method for manufacturing the wiring substrate 1 as described above includes the resist layer forming step and the plating step, the depth d1 of the recess 14 located on the surface of the electrode pad 12 is connected to the outside. It is shallower than the depth d2 of the recess 15 located on the surface of the terminal 13, the area a1 of the recess 14 in a plan view is smaller than the area a2 of the recess 15, and the thickness t1 of the electrode pad 12 is the external connection. It was possible to reliably manufacture the wiring substrate 1 which is larger than the thickness t2 of the terminal 13 and whose area A1 of the electrode pad 12 in a plan view is smaller than the area A2 of the external connection terminal 13. As a result, the wiring board 1 exhibiting the effects (1) to (4) could be reliably manufactured.
Therefore, according to the manufacturing method of the wiring board 1, the above (5) and (6) were obtained.

The present invention is not limited to the forms described above.
For example, the substrate main body 2 may be in the form of a single-layer ceramic layer, a single-layer or multi-layer resin layer, or a form in which a ceramic layer and a resin layer are laminated in an appropriate number of layers.
Further, in a substrate body in which a multi-layered ceramic layer, a multi-layered resin layer, and a ceramic layer and a resin layer are laminated, the uppermost ceramic layer or the resin layer is formed into a rectangular frame shape in a plan view, and inside the ceramic layer or the resin layer. It may have a cavity. In this case, the bottom surface of the cavity becomes the surface 3 of the substrate body 2.
Further, when the ceramic layer constituting the substrate body is made of low-temperature co-fired ceramic such as glass-ceramic, or is made of a resin layer, the metallized layers 6 to 8 and the inner layer wiring 9 are formed of copper or silver. ..

Further, the through conductor 5, the electrode pad 12, and the external connection terminal 13 may be made of silver, or may be made of metal portions independent of each other including the form made of copper, and may be arranged in close contact with each other. It may be in the form of a copper.
Further, the cross section of the through hole 5 and the through conductor 10 in the radial direction may be a regular polygon or a deformed polygon of a quadrangle or more, and each corner may be rounded. In this case, the tubular metallize layer 6 has a polygonal tubular shape following the above.
Further, a plurality of the through conductors 10 may be connected to one electrode pad 12 and one external connection terminal 13.
In addition, the shape of the electrode pad 12 and the external connection terminal 13 in a plan view may be circular or oval. In the case of these forms, the space provided in the front surface side resist layer 20 and the back surface side resist layer 22 is also similar to the above shape in a plan view.
In addition to the above, changes may be made as appropriate without departing from the spirit of the present invention.

According to the present invention, the thickness of the entire wiring board is not increased, the electrode pad having excellent mountability is provided on the surface of the substrate body made of a lucky material, and the penetrating conductor penetrating the substrate body and the back surface side. The external connection terminal provided can reliably provide another wiring board having excellent heat dissipation and a manufacturing method thereof.

1 ……………………………… Wiring board 2 ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… ……… Back side 5 ……………………………… Through hole 6-8 ………………………… Metallized layer 10 ………………………… Through conductor 12 ………… ……………… Electrode pad 13 ………………………… External connection terminals 14, 15 …………………… Recessed 20 ………………………… Surface side resist layer 21, 23 …………………… Space 22 ………………………… Back side resist layer A1, A2, a1, a2… Area d1, d2 …………………… Depth t1, t2 …… …………… Thickness c1, c2 ………………… Ceramic layer (insulating material, insulating plate)
g1, g2 …………………… Green sheet (insulation plate)

Claims (8)

A substrate body made of an insulating material and having opposite front and back surfaces,
Through holes that penetrate between the front and back surfaces of the substrate body,
With the through conductor formed in the through hole,
An electrode pad formed at a position surrounding the opening of the through hole on the surface of the substrate body, and
A wiring board provided with an external connection terminal formed at a position surrounding the opening of the through hole on the back surface of the board body.
In a plan view, the area of the electrode pad is smaller than the area of the external connection terminal, and the thickness of the electrode pad is larger than the thickness of the external connection terminal.
Recesses are individually formed on the surfaces of the electrode pad and the external connection terminal, and the depth of the recess located on the surface of the electrode pad is larger than the depth of the recess located on the surface of the external connection terminal. shallow,
A wiring board characterized by that. In a plan view, the area of the recess located on the surface of the electrode pad is smaller than the area of the recess located on the surface of the external connection terminal.
The wiring board according to claim 1. The through conductor, the electrode pad, and the external connection terminal are made of an integral metal or are made of different metal parts.
The wiring board according to claim 1 or 2. Between the inner wall surface of the through hole and the outer peripheral surface of the through conductor, between the surface of the substrate body and the bottom surface of the electrode pad, and between the back surface of the substrate body and the bottom surface of the external connection terminal. Is formed with a metallized layer,
The wiring board according to any one of claims 1 to 3, wherein the wiring board is characterized by this. It consists insulation material, and the substrate body and having opposite front and rear surfaces, a through hole passing through between the front and back surfaces of the substrate main body, a through conductor formed in the through hole, the substrate body A wiring board comprising an electrode pad formed at a position surrounding the opening of the through hole on the front surface of the substrate and an external connection terminal formed at a position surrounding the opening of the through hole on the back surface of the substrate main body. It ’s a manufacturing method,
A step of forming a through hole by punching or laser processing an insulating plate having an opposing front surface and a back surface to form a through hole penetrating between the front surface and the back surface.
A step of forming a metallized layer for forming a metallized layer over the inner wall surface of the through hole of the insulating plate and the positions surrounding the openings on both ends of the through hole on the front surface and the back surface of the insulating plate.
A step of forming a resist layer, which is arranged on the front surface and the back surface of the insulating plate and has a space surrounding each opening of the through hole, and a resist layer forming a back surface side resist layer.
And the inner surface of the cylindrical metallized layer formed on the inner wall surface of the through hole, the surface-side resist layer and the back-side resist front side metallization layer you position the bottom surface of the in each space layer and the back-side metallization layer A plating step of simultaneously applying electrolytic metal plating to the upper surface to form the through conductor, the electrode pad, and the external connection terminal is included.
In the plating step, the electrode pad and the external connection terminal are formed so that the depth of the recess located on the surface of the electrode pad is shallower than the depth of the recess located on the surface of the external connection terminal. ,
A method for manufacturing a wiring board, which is characterized in that. In the step of forming the resist layer, the area of the space in the plan view of the front surface side resist layer is smaller than the area of the space in the plan view of the back surface side resist layer.
The method for manufacturing a wiring board according to claim 5, wherein the wiring board is manufactured. In the step of forming the resist layer, a flat resist layer made of a photosensitive resin is individually formed on the front surface and the back surface of the insulating plate in which the through holes are formed, and then the two resist layers are subjected to the process. Exposure with different areas in plan view is performed individually.
The method for manufacturing a wiring board according to claim 5 or 6, wherein the wiring board is manufactured. After the plating step, there is an etching step of etching the front surface side resist layer and the back surface side resist layer and peeling them from the insulating plate.
A method for manufacturing a wiring board according to any one of claims 5乃optimum 7, characterized in that.

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