JP4622181B2 - Manufacturing method of electronic component mounting board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component mounting substrate suitable for application to an ultrahigh frequency MMIC (Microwave Monolithic IC) such as a GHz band and a method for manufacturing the same. Specifically, a substrate for mounting an electronic component is provided with a composite electrode, a plating base electrode layer and a plating intermediate electrode layer are used as core materials, and these electrode layers are covered with a plating-coated electrode layer made of another conductive member so as to wrap the whole. The composite electrode is configured so that a wiring electrode or the like optimal for wire bonding of a high frequency compatible electronic component such as a GHz band can be configured.
[0002]
[Prior art]
In recent years, with the development of semiconductor device manufacturing technology, ultra-high frequency semiconductor integrated circuit devices such as GHz bands have been manufactured. This type of semiconductor integrated circuit device is assumed to be incorporated in a mobile phone or the like. In a high-frequency compatible semiconductor device, it is necessary to consider a high-frequency resistance due to a high-frequency signal even if the semiconductor element and the wiring electrode are connected to each other as compared with a semiconductor device having a low operating frequency. As the high frequency resistance increases, the high frequency amplification gain decreases, which adversely affects reception sensitivity and the like. In order to eliminate this cause, the high frequency resistance is lowered.
[0003]
FIG. 7 is a cross-sectional view showing a structural example of the wiring electrode 2 of the electronic component mounting board 10 according to the conventional example. An electronic component mounting substrate 10 shown in FIG. 7 has a substrate 1 for mounting an electronic component having a low operating frequency. The substrate 1 is an organic substrate having at least a single-sided metal foil, and is provided with wiring electrodes 2 for connecting electronic components by wire bonding.
[0004]
The wiring electrode 2 is formed by sequentially performing nickel plating and gold plating using a copper layer 2A formed by patterning a copper foil as a core material. That is, the wiring electrode 2 has a shape in which the nickel layer 3 and the gold layer 4 cover the copper layer 2A of the core material. The nickel layer 3 is provided to receive the impact of the capillary during wire bonding. The capillary is a jig used when wire bonding is performed using a gold wire or the like, and the gold wire is strongly pressed against the wiring electrode 2 or the like by a jig tip made of metal or ceramics.
[0005]
[Problems to be solved by the invention]
By the way, if the structure of the normal wiring electrode 2 is applied as it is to the manufacture of a semiconductor integrated circuit device for ultra-high frequency such as GHz band, there are the following problems.
(1) According to this structure, since the nickel layer 3 and the gold layer 4 have a shape including the copper layer 2A as a core material, when a high frequency signal such as a GHz band is supplied to the wiring electrode 2, the wiring electrode 2 High-frequency current flows on the surface of 2 and the high-frequency resistance is further increased. The disadvantage of nickel is that its electrical resistance is more than three times that of copper or gold.
{Circle around (2)} When this high-frequency resistance increases, the high-frequency amplification gain or the like decreases, which causes a decrease in reception sensitivity, transmission output, or the like. Since the gold layer 4 cannot be made thick in terms of price, it is usually set to several μm or less, and the nickel layer 3 is affected when using a high frequency. In particular, the influence of the nickel layer 3 is significant in a high-frequency package used at 1 GHz or higher.
(3) Incidentally, in the wire bonding method, if the nickel layer 3 is omitted from the wiring electrode 2, the copper layer 2A below the gold layer 4 is soft, so that the thermocompression bonding force of the capillary is absorbed by the gold layer 4 and the copper layer 2A. Cause connection failure.
[0006]
Accordingly, the present invention solves such a conventional problem, and devise an electrode structure provided on a substrate for mounting an electronic component, which is optimal for wire bonding of a high-frequency compatible electronic component such as a GHz band. It is an object of the present invention to provide an electronic component mounting board and a method for manufacturing the same.
[0007]
[Means for Solving the Problems]
The above-described problem includes a substrate having a metal foil for mounting an electronic component, and an electrode provided on the substrate, and the electrode includes a plating base electrode layer formed by patterning the metal foil of the substrate, A plating intermediate electrode layer in which a conductive member is plated and laminated on the plating base electrode layer, and a plating coated electrode layer in which the plating base electrode layer and the plating intermediate electrode layer are covered with another conductive member and are entirely wrapped. It is solved by an electronic component mounting board characterized by having.
[0008]
The electronic component mounting substrate according to the present invention has a structure in which the plating base electrode layer and the plating intermediate electrode layer are used as cores, and these electrode layers are covered with a plating-coated electrode layer made of another conductive member so as to enclose the entire structure. A composite electrode can be formed. Moreover, by using a conductive member such as copper or gold having a low resistance for the plating base electrode layer and the plating coated electrode layer and using a relatively hard conductive member such as nickel for the plating intermediate electrode layer, a high frequency such as a GHz band is used. An electrode structure optimal for wire bonding of corresponding electronic components can be provided.
[0009]
A method of manufacturing an electronic component mounting substrate according to the present invention is a method of manufacturing an electrode on an insulating substrate having a metal foil on at least one surface, and the plating base electrode layer is formed by patterning the metal foil of the substrate. A step of forming a mask member so as to surround the plating base electrode and be higher than the thickness of the plating base electrode layer, and using the mask member as a mold to form a desired plating base electrode layer. And a step of plating the conductive member.
[0010]
According to the method of manufacturing an electronic component mounting substrate according to the present invention, when an electrode is formed on an insulating substrate having a metal foil on at least one surface, the height of the mask member is h, and the thickness of the plating base electrode If t is t, a plating intermediate electrode having a thickness (h−t) made of a desired conductive member whose side edges are vertically cut can be stacked on the plating base electrode. In addition, the conductive member is laminated only on the plating base electrode layer, and the side surface of the plating base electrode layer is not plated.
[0011]
Therefore, after removing the mask member, another conductive member is further plated so as to cover the side surface of the plating base electrode, the side surface of the plating intermediate electrode, and the top surface of the plating intermediate electrode. It is possible to realize a composite electrode structure in which the intermediate electrode is used as a core material and these electrodes are covered with another conductive member.
[0012]
Originally, high-frequency electronic components that take impedance control into consideration by forming wiring electrodes and terminal electrodes with a composite electrode structure that effectively uses a copper layer with low electrical resistance and controlling the shape of the composite electrode A mounting substrate can be provided.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Subsequently, an embodiment of an electronic component mounting board and a manufacturing method thereof according to the present invention will be described with reference to the drawings.
(1) Embodiment
FIG. 1 is a cross-sectional view showing an example of an electrode structure of an electronic component mounting board 100 as an embodiment according to the present invention.
In this embodiment, a substrate for mounting an electronic component is provided with an electrode having a composite electrode structure, a plating base electrode layer and a plating intermediate electrode layer are used as cores, and these electrode layers are covered with a plating coated electrode layer made of another conductive member. By enveloping the whole, it is possible to provide an electrode structure optimal for wire bonding of high frequency compatible electronic components such as the GHz band.
[0014]
An electronic component mounting substrate 100 shown in FIG. 1 has a substrate 11 for mounting electronic components. The substrate 11 is an organic substrate having at least a single-sided metal foil, and is provided with electrodes 12 for connecting electronic components. This electrode 12 has a plating base electrode layer 12A formed by patterning a copper foil as an example of a metal foil. A plating intermediate electrode layer 12B is provided on the plating base electrode layer 12A, and is formed by plating nickel as an example of a conductive member.
[0015]
The plating base electrode layer 12A and the plating intermediate electrode layer 12B are covered with the plating coating electrode layer 12C so as to wrap the whole. The plated electrode layer 12C is formed by gold plating as an example of another conductive member.
[0016]
Next, a method for forming the electronic component mounting substrate 100 will be described. 2A to 2D are cross-sectional views showing examples of forming the electronic component mounting substrate 100.
In this embodiment, it is assumed that the electrode 12 is manufactured on an organic substrate 11 having a copper foil 11A as an example of an insulating substrate on at least one surface. Using this as a manufacturing condition, a resist film 18 is selectively formed on the organic substrate 11 with a single-sided copper foil shown in FIG. 2A. For example, the resist film 18 is formed as follows. A resist (not shown) is applied to the entire surface of the copper foil 11 </ b> A of the organic substrate 11. Thereafter, the resist is exposed using the reticle onto which the electrode pattern is baked as a mask. Thereafter, the resist is developed. Thereby, a resist film 18 is formed.
[0017]
Then, the excess copper foil 11A is selectively etched and removed using the resist film 18 shown in FIG. 2A as a mask. Thereby, the plating base electrode layer 12A can be formed on one surface of the organic substrate 11 shown in FIG. 2B. Thereafter, the mask member 19 is formed so as to surround the plating base electrode layer 12A shown in FIG. 2C and to be higher than the thickness of the plating base electrode layer 12A. The mask member 19 is formed as follows, for example.
[0018]
First, a photoresist is formed on the entire surface of the organic substrate 11 having the plating base electrode layer 12A. For the photoresist, a dry film thicker than the thickness of the plating base electrode layer 12A is used. Thereafter, the dry film is exposed using the reticle onto which the electrode pattern is baked as a mask. Thereafter, the dry film is developed. Thereby, the mask member 19 which surrounds the plating base electrode layer 12A and is higher than the thickness of the plating base electrode layer 12A can be formed.
[0019]
Thereafter, a desired conductive member is electrolessly plated on the plating base electrode using the mask member 19 shown in FIG. 2C as a mold. At this time, a nickel plating solution is used as the electroless plating solution. Since plating is performed using a thick photoresist, a plating intermediate electrode layer 12B having a stable cross-sectional shape can be obtained.
[0020]
Thereby, the plating intermediate electrode layer 12B can be formed on the plating base electrode layer 12A shown in FIG. 2D. Thereafter, the dry film is removed, and the plating base electrode layer 12A and the plating intermediate electrode layer 12B are electrolessly plated. At this time, an electroless gold plating solution is used as the electroless plating solution. By this plating, the plating base electrode layer 12A and the plating intermediate electrode layer 12B are covered with the plating coating electrode layer 12C so as to wrap the whole.
[0021]
As a result, the gold layer on the outer peripheral surface of the electrode cross section is directly connected to the copper foil surface without the nickel layer, and the electrode 12 covered with the plated electrode layer 12C shown in FIG. 1 is completed. An electronic component is mounted on the substrate 11 on which the electrode 12 is formed. For example, the electronic component is a semiconductor chip that can be wire bonded.
[0022]
As described above, according to the electronic component mounting substrate 100 according to the embodiment of the present invention, the plating base electrode layer 12A and the plating intermediate electrode layer 12B are used as core materials, and these electrode layers are plated with other conductive members. It is possible to form a wiring electrode or a terminal electrode having a composite electrode structure that is covered with the electrode layer 12C and encases the entire electrode layer.
[0023]
In addition, by using a conductive member such as copper or gold having a low resistance for the plating base electrode layer 12A and the plating coating electrode layer 12C, and using a relatively hard conductive member such as nickel for the plating intermediate electrode layer 12B, the GHz band It is possible to provide an electronic component mounting substrate 100 that is optimal for wire bonding of electronic components that support high frequencies such as the above.
[0024]
(2) Examples
FIG. 3 is a sectional view showing a configuration example of a semiconductor element mounting substrate 200 as an embodiment according to the present invention.
In this embodiment, a semiconductor element mounting substrate 200 which is an example of an electronic component mounting substrate is configured, and the substrate 200 is provided with a wiring electrode having a composite electrode structure so that impact during wire bonding can be prevented by the plating intermediate electrode layer 12B. In addition, the high-frequency resistance can be reduced as compared with the conventional wiring electrode.
[0025]
A semiconductor element mounting substrate 200 shown in FIG. 3 is a PBGA (plastic ball grid array) by a wire bonding method using an organic substrate 21 which is an example of an insulating substrate. A processed prepreg, double-sided copper foil substrate or the like is used for the organic substrate 21. Wiring electrodes 22A and 22C, a die pad 22B, and the like are provided on one surface of the organic substrate 21, and a plurality of terminal electrodes 23 are provided on the back surface thereof. The wiring electrodes 22A, 22C and the terminal electrode 23 are electrically connected via a contact hole 24 in the substrate 21.
[0026]
The wiring electrodes 22A and 22C and the die pad 22B have a plating base electrode layer 12A made of copper foil and copper plating and a plating intermediate electrode layer 12B made of nickel plating as a core material, and these electrode layers are plated coating electrode layers 12C made of gold plating. It has a composite electrode structure that is covered and wrapped entirely.
[0027]
The total film thickness of the wiring electrodes 22A and the like is about 20 to 30 μm for the copper layer including the copper foil, 5 to 7 μm for the nickel layer, and about 0.1 to 5 μm for the gold layer. This is because the surface of the wiring electrode that is susceptible to the skin effect, for example, 5 μm, needs to be composed of a metal layer with low electrical resistance such as gold or copper. This is because the nickel layer is thick (5 μm or more) and has little stress-receiving effect unless it is plated.
[0028]
The terminal electrode 23 has a composite electrode structure in which a plating base electrode layer 12A made of copper foil and copper plating is covered with a plating coated electrode layer 12C made of gold plating and is entirely wrapped. The total film thickness of the terminal electrode 23 is about 20 to 30 μm for the copper layer including the copper foil and about 0.1 to 0.5 μm for the gold layer.
[0029]
A semiconductor element 25 is bonded (die-bonded) to the die pad 22B with an adhesive 17 or the like. The semiconductor element 25 includes, for example, a high-frequency transistor circuit that handles high-frequency signals in the GHz band. Wiring electrodes 22A and 22C are provided along the periphery or one side of the surface of the die pad 22B, and a plurality of terminal electrodes 23 are provided on the back surface of the die pad 22B.
[0030]
In some cases, the terminal electrode 23 is provided on the surface of the organic substrate 21 and some wiring electrodes 22A and 22C are provided on the back surface. A solder ball (bump electrode) 27 is formed on each terminal electrode 23. The solder balls 27 are provided for face-to-face bonding of the semiconductor element mounting board 200 to a printed wiring board or the like.
[0031]
A bonding element 20 and a contact hole 24 are interposed between the semiconductor element 25 bonded and supported by the die pad 22B, and between the wiring electrodes 22A and 22C and the terminal electrode 23 provided around the die pad 22B or along one side. Are electrically connected. In this example, the bonding wire 20 connects the semiconductor element 25 on the die pad 22B and the surrounding wiring electrodes 22A and 22C.
[0032]
At the time of wire bonding, the plating intermediate electrode layer 12B having a nickel composition in the composite electrode structure receives an impact. The semiconductor element 25 after bonding, the bonding wire 20, the wiring electrodes 22A and 22C, and the semiconductor element mounting substrate 200 are sealed with a mold resin 26. The material of the bonding wire 20 is gold. In the case of an alloy wire, a slight amount of Si, Ca or Pd metal is added to gold.
[0033]
Next, a method for manufacturing the semiconductor element mounting substrate 200 will be described. 4-6 is sectional drawing which shows the example of formation of the semiconductor element mounting board | substrate 200 (the 1-3).
In this embodiment, wiring electrodes 22A and 22C are formed on one surface of an organic substrate 21 having copper foils 11A and 11B on both sides, terminal electrodes 23 are formed on the other surface, and then a semiconductor element 25 is mounted. Assume a case.
In this case, the wiring electrodes 22A and 22C have a plating base electrode layer 12A made of copper foil and copper plating and a plating intermediate electrode layer 12B made of nickel plating as core materials, and these electrode layers are covered with a plating coated electrode layer 12C made of gold plating. Thus, a composite electrode structure that wraps the entire structure is obtained.
[0034]
The terminal electrode 23 is assumed to have a composite electrode structure in which a plating base electrode layer 12A made of copper foil and copper plating is covered with a plating coated electrode layer 12C made of gold plating and is entirely wrapped.
With this as a manufacturing condition, first, an organic substrate (copper-laminated laminated substrate) 21 having a double-sided copper foil shown in FIG. 4A is prepared. The organic substrate 21 may include a prepreg having an intermediate wiring layer. This organic substrate 21 is obtained by bonding a copper foil of 3 μm to 12 μm on both sides to a resin such as an epoxy of 0.1 mm to 2 mm or a BT resin.
[0035]
In FIG. 4B, contact holes 24 are formed in the organic substrate 21. The contact hole 24 is for electrically connecting the wiring electrodes 22A and 22C formed on one surface of the organic substrate 21 and the terminal electrode 23 formed on the back surface thereof. At this time, a through hole is formed in the organic substrate 21 using a drill or a laser beam, and the through hole is filled with copper by copper plating (electroless plating + electrolysis) called through-hole plating.
[0036]
At this time, copper plating having a thickness of about 20 μm to 30 μm is also laminated on the double-sided copper foil. In the copper plating, a copper sulfate electroless copper plating solution is heated to 70 ° C. in a plating bath, and the organic substrate 21 is immersed therein for about 30 minutes. With this plating condition, a copper plating of about 1 μm can be formed. By this method, the contact hole 24 can be formed by a copper-filled through hole capable of connecting and conducting the copper foils on both sides. In addition, when the immersion time in a plating solution is short, it is thin, and when it is long, it is thick.
[0037]
In FIG. 4C, the copper foils 11A and 11B on the front and back sides of the organic substrate 21 are patterned to form the plating base electrode layer 12A. At this time, a resist film (not shown) is selectively formed on the front and back of the organic substrate 21. For example, the resist film is formed as follows. A resist is applied to the entire surface of the copper foils 11 </ b> A and 11 </ b> B of the organic substrate 21. Thereafter, the resist is exposed using the reticle onto which the wiring electrode pattern and the terminal electrode pattern are baked as a mask. Thereafter, the resist is developed. Thereby, a resist film can be formed on the front and back of the organic substrate 21.
[0038]
Then, the excess copper foils 11A and 11B are selectively etched and removed using the resist film as a mask. Thereby, the plating base electrode layer 12A to be a part of the wiring electrodes 22A and 22C is formed on one surface of the organic substrate 21 shown in FIG. 4C, and a part of the terminal electrode 23 is formed on the other surface. A plating base electrode layer 12A can be formed. At this time, the base layer is similarly formed on the die pad 22.
[0039]
Thereafter, in FIG. 5A, the mask member 29 is formed so as to surround the plating base electrode layer 12A on the side on which the wiring electrodes 22A and 22C are formed with the organic substrate 21 and to be higher than the thickness of the plating base electrode layer 12A. Form. The mask member 29 is formed as follows, for example. At this time, the mask member 29 is similarly formed on the die pad 22.
[0040]
First, a resist is applied to the entire back surface of the organic substrate 21 to form a resist film 28 for preventing nickel plating. Thereafter, the dry film is developed. Photoresist walls are formed on the entire surface of the organic substrate 21 having the plating base electrode layer 12A. As the photoresist, a dry film thicker than the thickness of the plating base electrode layer 12A is used. The thickness of the dry film is about 35 μm to 40 μm.
[0041]
Thereafter, the dry film is exposed using a reticle onto which the wiring electrode pattern or die pad pattern is baked as a mask. The width of the wiring electrode pattern at this time is preferably designed to be about 35 μm wider than the width of the plating base electrode layer 12A. This is because copper plating reaches both sides of the plating base electrode layer 12A. Thereby, the mask member 29 surrounding the plating base electrode layer 12A and having a thickness higher than that of the plating base electrode layer 12A can be formed. The height of the wall of the mask member 29 is 35 μm to 40 μm.
[0042]
Here, assuming that the height of the mask member 29 is h and the thickness of the plating base electrode layer 12A is t, the maximum is (ht), which is made of nickel plating with the side edges vertically standing on the plating base electrode layer 12A. ) Thick plating intermediate electrode layer 12B can be stacked.
[0043]
Thereafter, a desired conductive member is plated on the plating base electrode layer 12A using the mask member 29 shown in FIG. 5A as a mold. Here, a copper plating solution and a nickel plating solution, which are examples of conductive members with respect to the electroless plating solution, are used. The copper plating is as described above.
[0044]
Nickel plating is performed by heating an electroless nickel plating solution (manufactured by World Metal Co., Ltd .: trade name Top Chemical Alloy 66) or the like to 65 ° C. in a plating bath and immersing the organic substrate 21 therein for about 30 minutes. . Thereby, nickel plating of about 5 μm can be formed. At this time, the die pad 22 is similarly nickel-plated.
[0045]
Since copper plating and nickel plating are sequentially performed using a thick photoresist, the plating intermediate electrode layer 12B having a stable cross-sectional shape is obtained. Thereby, the plating intermediate electrode layer 12B made of nickel plating can be formed on the plating base electrode layer 12A made of copper foil and copper plating shown in FIG. 5B. Thereafter, the dry film is removed using an aqueous alkali solution. The resist film 28 on the back surface of the organic substrate 21 is also removed. This example is characterized in that the plating side surface is sharply cut by the width being regulated by the effect of the dry film (resist film).
[0046]
In FIG. 5C, the plating base electrode layer 12A and the plating intermediate electrode layer 12B are electrolessly plated. At this time, an electroless gold plating solution as an example of another conductive member is used as the plating solution. Gold plating is performed by heating an electroless gold plating solution (trade name: HGS-2000, manufactured by Hitachi Chemical Co., Ltd.) or the like to 65 ° C. in a plating bath, and immersing the organic substrate 21 therein for about 20 minutes.
[0047]
Thereby, gold plating of about 0.3 μm can be formed. By this gold plating, the plating base electrode layer 12A and the plating intermediate electrode layer 12B are covered with a plating-coated electrode layer 12C having a thickness of about 0.1 μm to 0.5 μm so as to wrap the whole. Thereby, the wiring electrodes 22A and 22C and the terminal electrode 23 having a composite electrode structure covered with the plating coated electrode layer 12C are formed. In this composite electrode structure, gold and copper foil are directly connected on the side surface of the electrode without using nickel (see FIG. 1).
[0048]
Thereafter, the semiconductor element 25 (LSI chip) is bonded onto the die pad 22B shown in FIG. 6A. The semiconductor element 25 is bonded (die-bonded) to the die pad 22B with an adhesive 17 or the like. Then, the semiconductor element 25 bonded to the die pad 22B and the wiring electrodes 22A and 22C are automatically bonded by a capillary (not shown). The capillary is attached to a thermocompression bonding or ultrasonic thermocompression bonding automatic bonder, and the bonding wire 20 is thermocompression bonding or ultrasonic thermocompression bonding to the pad electrode of the semiconductor element 25 or the wiring electrodes 22A and 22C on the organic substrate 21. To be made.
[0049]
6B, a part or all of the bonding wires 20, the wiring electrodes 22A and 22C, the die pad 22B, and the semiconductor element 25 on the surface of the organic substrate 21 are sealed with a mold resin 26 such as an epoxy resin. At this time, the organic substrate 21 to which the semiconductor element 25 is bonded is set in the mold resin injection shaping apparatus, and resin sealing is performed using a mold having a predetermined shape. Then, solder balls 27 are formed on the plurality of terminal electrodes 23 on the back surface of the organic substrate 21. The solder balls 27 are for connecting to the printed circuit board 11. Then, after conducting an electrical measurement inspection, the semiconductor element mounting substrate 200 shown in FIG. 3 is completed.
[0050]
Thus, according to the electronic component mounting substrate and the manufacturing method thereof according to the present invention, when the wiring electrodes 22A, 22C and the terminal electrodes 23 are formed on the organic substrate 21 having the copper foil on both surfaces, the plating base electrode layer 12A is formed. A plated intermediate electrode layer 12B made of nickel plating with side edges vertically cut can be stacked thereon. In addition, nickel plating is laminated only on the plating base electrode layer 12A, and copper plating is performed on the side surface of the plating base electrode layer 12A, but nickel plating is not performed on the side surface.
[0051]
Accordingly, after removing the mask member 29, electroless gold plating is further performed so as to cover the side surface of the plating base electrode layer 12A, the side surface of the plating intermediate electrode layer 12B, and the upper surface of the plating intermediate electrode layer 12B. The wiring electrodes 22A and 22C having a composite electrode structure in which the plating base electrode layer 12A and the plating intermediate electrode layer 12 are used as core materials and these laminated electrodes are covered with gold plating can be formed with good reproducibility.
[0052]
The wiring electrodes 22A and 22C of this composite electrode structure have a nickel plating layered only on the plating base electrode layer 12A, compared with a case where nickel plating and gold plating are simply performed using copper foil as a core. Since it is not applied to the side surface, the high-frequency current does not flow through the nickel plating layer having high electrical resistance, but flows through the plating base electrode layer 12A, which is a copper foil, and the plating coating electrode layer 12C made of a gold plating layer (skin effect) ).
[0053]
The plating intermediate electrode layer 12B by nickel plating maintains a predetermined shape such as the plating base electrode layer 12A against stress from the upper surface during wire bonding. As a result, it is possible to provide a high-frequency compatible semiconductor element mounting substrate 200 that is hardly affected by the nickel layer having a high electrical resistance and has improved high-frequency characteristics such as a GHz band. In particular, since the impedance characteristics of the wiring electrodes 22A and 22C are excellent in the formation of a high-frequency circuit, a stable inductor (coil element) can be formed.
[0054]
【The invention's effect】
As described above, according to the electronic component mounting substrate according to the present invention, the electrode provided on the electronic component mounting substrate includes the plating base electrode layer formed by patterning the metal foil of the substrate, It has a plating intermediate electrode layer in which a conductive member is plated and laminated on a plating base electrode layer, and a plating coated electrode layer in which the plating base electrode layer and the plating intermediate electrode layer are covered with another conductive member and entirely wrapped. is there.
[0055]
With this configuration, it is possible to form a composite electrode having a structure in which the plating base electrode layer and the plating intermediate electrode layer are used as core materials, and these electrode layers are covered with a plating-coated electrode layer made of another conductive member so as to enclose the entire structure. . Moreover, by using a conductive member such as copper or gold having a low resistance for the plating base electrode layer and the plating coated electrode layer and using a relatively hard conductive member such as nickel for the plating intermediate electrode layer, a high frequency such as a GHz band is used. An electrode structure optimal for wire bonding of corresponding electronic components can be provided.
[0056]
According to the method for manufacturing an electronic component mounting substrate according to the present invention, when forming an electrode on an insulating substrate having a metal foil on at least one surface, the metal foil on the substrate is patterned to form a plating base electrode. Then, a mask member is formed so as to surround the plating base electrode layer and to be higher than the thickness of the plating base electrode layer. A desired conductive member is plated.
[0057]
With this configuration, one conductive member is laminated only on the plating base electrode layer, and it is not plated on the side surface of the plating base electrode layer. The plating intermediate electrode layer can be stacked on the plating base electrode layer. Therefore, it is possible to manufacture an electrode having a structure in which the plating base electrode layer and the plating intermediate electrode layer are used as cores, and these electrode layers are covered with other conductive members and are entirely wrapped.
The present invention is very suitable when applied to MMICs for ultra-high frequencies such as the GHz band.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an electrode structure of an electronic component mounting substrate 100 as an embodiment according to the present invention.
2A to 2D are cross-sectional views showing examples of forming an electronic component mounting substrate 100. FIG.
FIG. 3 is a cross-sectional view showing a configuration example of a semiconductor element mounting substrate 200 as an embodiment according to the present invention.
FIGS. 4A to 4C are cross-sectional views illustrating a first example of forming a semiconductor element mounting substrate 200; FIGS.
FIGS. 5A to 5C are cross-sectional views showing a formation example (No. 2) of the semiconductor element mounting substrate 200; FIGS.
FIGS. 6A and 6B are cross-sectional views showing a formation example (part 3) of the semiconductor element mounting substrate 200; FIGS.
FIG. 7 is a cross-sectional view showing a structural example of a wiring electrode 2 of an electronic component mounting board 10 according to a conventional example.
[Explanation of symbols]
11, 21 ... Organic substrate (substrate), 12 ... Electrode, 12A ... Plated base electrode layer, 12B ... Plating intermediate electrode layer, 12C ... Plating coated electrode layer, 22A, 22C ... -Wiring electrode, 22B ... Die pad, 23 ... Terminal electrode, 24 ... Contact hole, 25 ... Semiconductor element, 26 ... Mold resin, 27 ... Solder ball, 100 ... Electron Component mounting board, 200... Semiconductor element mounting board

Claims (8)

A wiring electrode and a die pad are provided on one surface of the substrate by a first plating base electrode layer, a plating intermediate electrode layer, and a first plating coating electrode layer, and a terminal electrode is second plated on the other surface of the substrate. A process of manufacturing an electronic component mounting board by providing the base electrode layer and the second plating-coated electrode layer.
  Have
  The step of manufacturing the electronic component mounting substrate includes:
Forming the first plating base electrode layer by patterning the first metal foil formed on the one surface of the substrate and patterning the second metal foil formed on the other surface of the substrate; Forming a second plating base electrode layer by a metal foil patterning step;
A mask member forming step of forming a mask member so as to surround the first plating base electrode layer on the one surface of the substrate and to be higher than the thickness of the first plating base electrode layer;
Forming a plating intermediate electrode layer on the first plating base electrode layer by plating a conductive member on the first plating base electrode layer using the mask member as a mold; a first plating step;
Removing the mask member from the one surface of the substrate;
The one surface of the substrate is plated with another conductive member different from the conductive member so as to cover the side surface of the first plating base electrode layer and the side surface and top surface of the plating intermediate electrode layer. The second plating coating is formed by forming a first plating coating electrode layer and plating the other surface of the substrate with the other conductive member so as to cover a side surface and an upper surface of the second plating base electrode layer. A second plating step for forming an electrode layer;
including,
Manufacturing method of electronic component mounting board. A resist film is formed so as to cover the second plating base electrode layer on the other surface of the substrate after the metal foil patterning step and before the first plating step. A resist film forming step;
A resist film removing step of removing the resist film from the other surface of the substrate after the first plating step and before the second plating step;
including,
The manufacturing method of the electronic component mounting board | substrate of Claim 1. Forming a contact hole for electrically connecting the first metal foil and the second metal foil in the substrate before the metal foil patterning step;
including,
The manufacturing method of the electronic component mounting substrate of Claim 1 or 2. A bonding step of bonding the semiconductor element and the wiring electrode with a bonding wire after bonding the semiconductor element on the die pad with an adhesive;
including,
The manufacturing method of the electronic component mounting board in any one of Claim 1 to 3. A sealing step of sealing the bonding wire, the wiring electrode, the die pad, and the semiconductor element with a mold resin on the one surface of the substrate;
Forming a solder ball on the terminal electrode on the other surface of the substrate;
including,
The manufacturing method of the electronic component mounting board | substrate of Claim 4. In the metal foil patterning step, the copper foil formed as the first metal foil and the second metal foil is patterned,
In the first plating step, before removing the mask member, after performing copper plating, performing nickel plating,
In the second plating step, gold plating is performed.
The manufacturing method of the electronic component mounting board in any one of Claim 1 to 5. In the first plating step, the copper plating and the nickel plating are performed by electroless plating,
In the second plating step, the gold plating is performed by electroless plating.
The manufacturing method of the electronic component mounting board | substrate of Claim 6. About the wiring electrode and the die pad,
The first plating base electrode layer is formed to have a thickness of 20 to 30 μm,
The plating intermediate electrode layer is formed to have a thickness of 5 to 7 μm,
Forming the first plating-coated electrode layer to have a thickness of 0.1 to 5 μm;
For the terminal electrode,
The second plating base electrode layer is formed to have a thickness of 20 to 30 μm,
The second plating-coated electrode layer is formed to have a thickness of 0.1 to 5 μm.
The manufacturing method of the electronic component mounting board of Claim 7.

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