JP2023171155A - Mounting board, manufacturing method of mounting board, and mounting board intermediate - Google Patents

Abstract

To provide a mounting board capable of improving adhesion between a metal layer and an insulating layer while reducing undercut in the metal layer.SOLUTION: A mounting board 2 includes: an insulation layer 6; and a metal layer 8 arranged in contact with one side of the insulation layer 6. One side of the insulation layer 6 includes: a first region 10 forming an interface with the metal layer 8, and a second region 12 other than the first region 10. The surface roughness in the first region 10 and the surface roughness in the second region 12 are different from each other.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a mounted board, a method for manufacturing a mounted board, and a mounted board intermediate.

A semi-additive process (SAP) is known as a technique for forming fine wiring layers on a mounting board (for example, see Patent Document 1). In this SAP, first, the entire surface of an insulating layer formed of an insulating resin is uniformly roughened (that is, with a uniform surface roughness) by desmear treatment. Next, a seed layer made of copper is formed on the insulating layer by electroless plating. A resist having openings is then formed on the seed layer. This opening is formed in a region corresponding to the wiring layer.

Next, a wiring layer pattern made of copper is formed on the seed layer in the opening of the resist by electrolytic plating. The resist is then removed to expose the seed layer. Finally, the exposed seed layer is etched using the wiring layer pattern as a mask. As a result, a fine wiring layer composed of a seed layer and a wiring layer pattern is formed on the insulating layer.

Japanese Patent Application Publication No. 2008-135445

In the conventional SAP described above, the entire surface of the insulating layer is uniformly roughened, so if the roughened surface of the insulating layer is relatively smooth, poor adhesion between the insulating layer and the seed layer may occur. There is a risk that this may occur. On the other hand, if the roughened surface of the insulating layer is relatively rough, it becomes difficult to form a fine wiring layer on the insulating layer.

In addition, when forming a seed layer on the roughened surface of the insulating layer, in order to use the seed layer as a plating power supply layer in electrolytic plating, the film thickness of the seed layer must be adjusted to the surface of the insulating layer. It is necessary to make the height difference larger than the height difference between the formed unevenness. As a result, it is necessary to strongly etch the seed layer, which may lead to undercutting in the seed layer at the base of the wiring layer, resulting in wiring defects.

The present disclosure has been made to solve such problems, and provides a mounting board that can improve the adhesion between a metal layer and an insulating layer and reduce undercutting of the metal layer. , an object of the present invention is to provide a method for manufacturing a mounting board, and a mounting board intermediate.

In order to achieve the above object, one embodiment of a mounting board according to the present disclosure includes an insulating layer and a metal layer disposed so as to be in contact with one surface of the insulating layer, One surface includes a first region forming an interface with the metal layer and a second region other than the first region, and the surface roughness of the first region and the second region are different from each other in surface roughness.

Further, one aspect of the method for manufacturing a mounting board according to the present disclosure includes the steps of preparing a transfer plate having an opening, forming a metal main body layer in the opening of the transfer plate, and exposing metal from the opening. The metal layer including the metal body layer is roughened by roughening the end face of the metal body layer, and by transferring the end face of the metal body layer to one side of the insulating layer using a transfer method. forming on the insulating layer.

Further, one embodiment of the mounting board intermediate according to the present disclosure is a mounting board intermediate for forming a mounting board using a plate member having an opening, wherein the mounting board intermediate is disposed in the opening of the plate member. a first metal layer, the end surface of which is exposed from the opening, has a fine uneven structure; and the end surface of the first metal layer, which is exposed from the opening. and a second metal layer disposed over a region other than the opening region of the plate member, the second metal layer disposed over the end surface of the first metal layer. The thickness of the second metal layer is smaller than the thickness of the second metal layer on the other region of the plate member.

According to the mounting board and the like in the present disclosure, it is possible to improve the adhesion between the metal layer and the insulating layer, and to reduce undercutting of the metal layer.

1 is a cross-sectional view of a mounting board according to Embodiment 1. FIG. FIG. 2 is an enlarged cross-sectional view of a part of the mounting board of FIG. 1; 1 is a diagram for explaining a method for manufacturing a mounting board according to Embodiment 1. FIG. FIG. 2 is a cross-sectional view of a mounting board intermediate obtained during the process of manufacturing a mounting board according to the first embodiment. FIG. 7 is a diagram for explaining a method for manufacturing a mounting board according to a comparative example. FIG. 3 is a cross-sectional view of a mounting board according to a second embodiment. FIG. 7 is a diagram for explaining a method for manufacturing a mounting board according to a second embodiment. FIG. 7 is a diagram for explaining a method for manufacturing a mounting board according to a second embodiment. FIG. 7 is a diagram for explaining a method for manufacturing a mounting board according to a second embodiment. FIG. 3 is a cross-sectional view of a mounting board according to a third embodiment. FIG. 7 is a diagram for explaining a method for manufacturing a mounting board according to Embodiment 3;

Embodiments of the present disclosure will be described below with reference to the drawings. Note that the embodiments described below each represent a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, arrangement positions and connection forms of the components, etc. shown in the following embodiments are merely examples and do not limit the present disclosure. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims representing the most important concept of the present disclosure will be described as arbitrary constituent elements.

Note that each figure is a schematic diagram and is not necessarily strictly illustrated. Therefore, the scale etc. of each figure do not necessarily match. Further, in each figure, substantially the same configurations are denoted by the same reference numerals, and overlapping explanations will be omitted or simplified.

(Embodiment 1)
[1-1. Configuration of mounting board]
First, the configuration of the mounting board 2 according to the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view of a mounting board 2 according to the first embodiment. FIG. 2 is an enlarged cross-sectional view of a part of the mounting board 2 of FIG. 1. As shown in FIG.

As shown in FIG. 1, the mounting board 2 according to the first embodiment is, for example, an ultra-high density semiconductor package board. The mounting board 2 includes a substrate 4, an insulating layer 6, and a plurality of metal layers 8.

The substrate 4 has a conductor (not shown). The conductor is, for example, a wiring or an electrode formed in a wiring layer different from the metal layer 8. As an example, the board 4 is a wiring board having wiring formed of copper foil or the like, such as a build-up board, a multilayer mounting board, a double-sided mounting board, or a single-sided mounting board. Therefore, on the substrate 4, a plurality of wirings and the like are arranged as conductors in a single layer or in multiple layers.

Insulating layer 6 is arranged on substrate 4 . Specifically, the insulating layer 6 is arranged so as to cover the entire one surface (the upper surface in FIG. 1) of the substrate 4. Further, the insulating layer 6 is arranged between the substrate 4 and the plurality of metal layers 8. That is, the insulating layer 6 functions as an interlayer insulating layer that electrically insulates the wiring layer on which the conductor of the substrate 4 is formed and the wiring layer on which the plurality of metal layers 8 are formed. The insulating layer 6 is made of an insulating material. In this embodiment, the insulating material forming the insulating layer 6 is, for example, an insulating resin such as an epoxy resin or a polyimide resin.

One surface of the insulating layer 6 (the surface opposite to the substrate 4) includes a first region 10 forming an interface with the metal layer 8 and a second region other than the first region 10. 12. The surface roughness of the first region 10 and the second region 12 are different from each other. Specifically, the surface roughness of the first region 10 is greater than the surface roughness of the second region 12. More specifically, in the first region 10, a fine first uneven structure 14 is formed. Further, the second region 12 is formed in a flat shape, and no fine uneven structure is formed in the second region 12. The surface roughness of the first uneven structure 14 (first region 10) is, for example, 10 nm to 300 nm in root mean square roughness Rq, more preferably 20 nm to 100 nm. Note that in this specification, "fine" means having a size of several hundred nm or less.

Note that, in order to facilitate understanding, the size of the first uneven structure 14 is exaggerated in FIGS. 1 and 2. Further, in FIGS. 1 and 2, the cross-sectional shape of the first uneven structure 14 is schematically illustrated as a sawtooth shape, but the cross-sectional shape of the first uneven structure 14 is not limited to this. It may be a shape.

A plurality of metal layers 8 are arranged on the insulating layer 6. Specifically, the plurality of metal layers 8 are arranged so as to be in contact with one surface of the insulating layer 6 and are arranged above the substrate 4 with the insulating layer 6 interposed therebetween. Note that the plurality of metal layers 8 are formed on the insulating layer 6 by a transfer method using a transfer plate, which will be described later.

As shown in FIGS. 1 and 2, each of the plurality of metal layers 8 includes a wiring body layer 8a (an example of a first metal layer and a metal body layer) and a protective layer 8b (an example of a second metal layer). It has

The wiring main body layer 8a is an electroplated film formed by electrolytic plating. Specifically, the wiring body layer 8a is an electrolytic Cu plating film formed of copper (Cu). A fine second uneven structure 16 is formed on the end surface of the wiring main body layer 8a (the surface on the side facing the first region 10 of the insulating layer 6). The second uneven structure 16 has a shape corresponding to the first uneven structure 14 of the insulating layer 6 and is fitted with the first uneven structure 14 . The surface roughness of the second concavo-convex structure 16 (end surface of the wiring main body layer 8a) is, for example, 10 nm to 300 nm in root mean square roughness Rq, more preferably 20 nm to 100 nm.

Note that, in order to facilitate understanding, the size of the second concavo-convex structure 16 is exaggerated in FIGS. 1 and 2. Further, in FIGS. 1 and 2, the cross-sectional shape of the second uneven structure 16 is schematically illustrated as a sawtooth shape, but the cross-sectional shape of the second uneven structure 16 is not limited to this. It may be a shape.

The protective layer 8b is a layer for preventing the transfer plate and the insulating layer 6 from coming into close contact with each other when the metal layer 8 is formed on the insulating layer 6 by a transfer method using a transfer plate, which will be described later. . The protective layer 8b is formed in an uneven shape along the surface of the first uneven structure 14. That is, the protective layer 8b is interposed at the interface between the first uneven structure 14 and the second uneven structure 16.

The protective layer 8b is an electroless plated film formed by electroless plating. Specifically, the protective layer 8b is an electroless Cu plating film made of copper. As shown in FIG. 2, the thickness D1 of the protective layer 8b is 100 nm or less. Specifically, the film thickness D1 of the protective layer 8b is smaller than the difference H between the maximum height and minimum height of the first uneven structure 14 from the reference position (for example, the interface between the substrate 4 and the insulating layer 6). , for example, 50 nm.

[1-2. Manufacturing method of mounting board]
Next, a method for manufacturing the mounting board 2 according to the first embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a diagram for explaining a method for manufacturing the mounting board 2 according to the first embodiment. FIG. 4 is a cross-sectional view of the mounting board intermediate body 28 obtained during the process of manufacturing the mounting board 2 according to the first embodiment.

First, as shown in FIG. 3(a), a transfer plate 18 (an example of a plate member) is prepared. The transfer plate 18 includes a base material 20, a seed layer 22, and an insulating layer 24. The base material 20 is made of, for example, a silicon substrate, a glass substrate, or a metal substrate. The seed layer 22 is a seed electrode made of a conductive material for forming the wiring body layer 8a by electrolytic plating, and is disposed on the base material 20. Insulating layer 24 is disposed on seed layer 22 . The insulating layer 24 is made of, for example, insulating resin. A plurality of openings 26 are formed in the insulating layer 24 for forming the wiring main body layer 8a. The seed layer 22 is exposed in these plurality of openings 26 . Note that the upper surface of the insulating layer 24 (the surface opposite to the seed layer 22) is formed in a flat shape. The surface roughness of the upper surface of the insulating layer 24 is, for example, 10 nm or less in root mean square roughness Rq.

Next, as shown in FIG. 3B, an electrolytic Cu plating film made of copper is formed on the seed layer 22 in the opening 26 of the insulating layer 24 of the transfer plate 18 by electrolytic plating. As a result, the wiring body layer 8a, which is an electrolytic Cu plating film, is formed on the seed layer 22 in the opening 26 of the insulating layer 24 of the transfer plate 18.

Next, as shown in FIG. 3C, the end surface of the wiring body layer 8a exposed from the opening 26 of the insulating layer 24 of the transfer plate 18 is roughened by, for example, wet etching using an etching solution. As a result, a second uneven structure 16 is formed on the end face of the wiring main body layer 8a. At this time, only the end surface of the wiring body layer 8a is roughened, and the upper surface of the insulating layer 24 of the transfer plate 18 is maintained flat without being roughened. Note that if the end surface of the wiring body layer 8a is rougher than the upper surface of the insulating layer 24, the step of roughening the end surface of the wiring body layer 8a described above (the step shown in FIG. 3(c)) may be omitted. good.

Next, as shown in FIG. 3(d), electroless plating is applied to the end surface of the wiring body layer 8a exposed through the opening 26 of the insulating layer 24 of the transfer plate 18 and the insulation of the transfer plate 18. An electroless Cu plating film made of copper is formed over the layer 24 (that is, over the area other than the opening 26 of the insulating layer 24). As a result, the protective layer 8b, which is an electroless Cu plating film, is formed over the end surface of the wiring main layer 8a and over the insulating layer 24 of the transfer plate 18. At this time, the protective layer 8b on the end face of the wiring body layer 8a is formed in an uneven shape along the surface of the second uneven structure 16. Further, the protective layer 8b in the insulating layer 24 of the transfer plate 18 is formed flat along the surface of the insulating layer 24.

A mounting board intermediate body 28 is formed on the transfer plate 18 by the step shown in FIG. 3(d). The mounting board intermediate body 28 is obtained during the process of manufacturing the mounting board 2. As shown in FIG. 4, the mounting board intermediate 28 includes a wiring body layer 8a disposed in the opening 26 of the insulating layer 24 of the transfer plate 18 and a wiring body layer 8a disposed in the opening 26 of the insulating layer 24 of the transfer plate 18. It has a protective layer 8b disposed over the end surface of the wiring body layer 8a and over the insulating layer 24 of the transfer plate 18. The thickness D1 of the protective layer 8b on the end surface of the wiring body layer 8a is smaller than the thickness D2 of the protective layer 8b on the insulating layer 24 of the transfer plate 18. This is because, in the electroless plating method in the step shown in Figure 3(d), the mechanism by which the electroless Cu plating film is deposited is different between the metal and the resin, and it is easier to deposit the electroless Cu plating film on the resin than on the metal. This is because the reaction that deposits the electroless Cu plating film is likely to proceed.

Next, as shown in FIG. 3E, a substrate 4 with an insulating layer 6 formed thereon is prepared in advance, and the mounting substrate intermediate 28 formed on the transfer plate 18 is placed on the substrate 4. It is made to face one side of the insulating layer 6 formed on the substrate. Then, the mounting board intermediate body 28 is separated from the transfer plate 18 by a transfer method using, for example, a hot press, and the mounting board intermediate body 28 is transferred onto one surface of the insulating layer 6. As a result, the end face of the wiring main body layer 8a and the protective layer 8b are transferred to one surface of the insulating layer 6, and the wiring main body layer 8a and the protective layer 8b are formed on the insulating layer 6. Note that during transfer, by interposing the protective layer 8b between the transfer plate 18 and the insulating layer 6, it is possible to avoid the transfer plate 18 and the insulating layer 6 from coming into close contact with each other, and the mounting board intermediate 28 can be easily separated from the transfer plate 18.

By this transfer method, the second uneven structure 16 of the wiring body layer 8a is transferred to the first region 10 of the insulating layer 6, so that a second uneven structure 16 having a shape corresponding to the shape of the second uneven structure 16 is transferred to the first region 10 of the insulating layer 6. One uneven structure 14 is formed. Furthermore, the protective layer 8b is transferred over the entire one surface of the insulating layer 6 (the first region 10 and the second region 12). As a result, the protective layer 8b is exposed in the second region 12 of the insulating layer 6.

Finally, as shown in FIG. 3F, the protective layer 8b exposed in the second region 12 of the insulating layer 6 is etched using an etching solution using the wiring main layer 8a as a mask. As a result, the protective layer 8b exposed in the second region 12 of the insulating layer 6 is removed, and a fine metal layer 8 composed of the wiring main layer 8a and the protective layer 8b is formed on the insulating layer 6. Ru. As described above, the mounting board 2 is manufactured.

[1-3. effect]
Here, a method for manufacturing a mounting board 100 according to a comparative example will be described with reference to FIG. FIG. 5 is a diagram for explaining a method of manufacturing a mounting board 100 according to a comparative example.

As shown in FIG. 5A, the entire surface of the insulating layer 102 made of insulating resin is uniformly roughened (that is, with a uniform surface roughness) by desmearing. Next, as shown in FIG. 5B, a seed layer 104, which is an electroless Cu plating film, is formed on the insulating layer 102 by electroless plating. Next, as shown in FIG. 5C, a resist 108 having an opening 106 is formed on the seed layer 104. Next, a wiring layer pattern 110, which is an electrolytic Cu plating film, is formed on the seed layer 104 in the opening 106 of the resist 108 by electrolytic plating.

Next, as shown in FIG. 5(d), the resist 108 is removed to expose the seed layer 104. Finally, as shown in FIG. 5E, the exposed seed layer 104 is etched using the wiring layer pattern 110 as a mask. As a result, a fine wiring layer 112 composed of the seed layer 104 and the wiring layer pattern 110 is formed on the insulating layer 102.

However, in such a manufacturing method, the entire surface of the insulating layer 102 is uniformly roughened, so if the roughened surface of the insulating layer 102 has a relatively smooth shape, the insulating layer 102 and the seed layer 104 may occur. On the other hand, if the roughened surface of the insulating layer 102 is relatively rough, it becomes difficult to form the fine wiring layer 112 on the insulating layer 102.

Further, when forming the seed layer 104 on the roughened surface of the insulating layer 102, in order to use the seed layer 104 as a plating power supply layer in electrolytic plating, the film thickness of the seed layer 104 should be It is necessary to make the difference in height larger than the difference in height between the unevenness formed on the surface. As a result, it is necessary to strongly etch the seed layer 104, which may lead to undercutting in the seed layer 104 at the base of the wiring layer 112, resulting in wiring defects.

In contrast, in the present embodiment, the mounting board 2 includes an insulating layer 6 and a metal layer 8 disposed so as to be in contact with one surface of the insulating layer 6. One surface of the insulating layer 6 includes a first region 10 forming an interface with the metal layer 8 and a second region 12 other than the first region 10. The surface roughness of the first region 10 and the second region 12 are different from each other.

According to this, since the surface roughness of the first region 10 and the surface roughness of the second region 12 are different from each other, the surface roughness of the first region 10 and the surface roughness of the second region 12 are different from each other. When etching the protective layer 8b with an etching liquid, the etching liquid becomes difficult to penetrate into the first region 10. As a result, undercuts in the metal layer 8 can be reduced. Moreover, the adhesion between the metal layer 8 and the insulating layer 6 can be improved due to the anchor effect.

Further, in this embodiment, the surface roughness of the first region 10 is greater than the surface roughness of the second region 12.

According to this, the adhesion between the metal layer 8 and the insulating layer 6 can be improved, and the high frequency characteristics can be improved.

Furthermore, in the present embodiment, a fine first uneven structure 14 is formed in the first region 10 . Further, the second region 12 is formed in a flat shape.

According to this, the adhesion between the metal layer 8 and the insulating layer 6 can be improved, and the high frequency characteristics can be improved.

Further, in the present embodiment, the metal layer 8 is a fine second uneven structure 16 having a shape corresponding to the first uneven structure 14, and a second uneven structure 16 that fits into the first uneven structure 14. It includes a wiring main body layer 8a on which a concavo-convex structure 16 is formed, and a protective layer 8b interposed between the first concave-convex structure 14 and the second concave-convex structure 16.

According to this, in the process of producing the mounting board 2 by the transfer method using the transfer plate 18, it is possible to avoid the transfer plate 18 and the insulating layer 6 from coming into close contact with each other.

Further, in this embodiment, the film thickness D1 of the protective layer 8b is smaller than the difference H between the maximum height and the minimum height of the first uneven structure 14.

According to this, in the process of manufacturing the mounting board 2, when the protective layer 8b exposed in the second region 12 of the insulating layer 6 is etched with an etching solution, the etching solution enters the first region 10. It becomes difficult. As a result, undercuts in the metal layer 8 can be reduced.

Further, in this embodiment, the steps of preparing the transfer plate 18 having the opening 26, forming the wiring body layer 8a in the opening 26 of the transfer plate 18, and the wiring body layer exposed from the opening 26 are described. The metal layer 8 including the wiring body layer 8a is transferred to the insulating layer 6 by roughening the end face of the wiring body layer 8a and transferring the end face of the wiring body layer 8a to one surface of the insulating layer 6 using a transfer method. forming on the top.

According to this, the surface roughness of the interface between the insulating layer 6 and the metal layer 8 and the surface roughness of the exposed portion of the insulating layer 6 (where the metal layer 8 is not formed) can be easily made different. .

Further, in this embodiment, the mounting board intermediate body 28 is a mounting board intermediate body for forming the mounting board 2 using the transfer plate 18 having the opening 26. The mounting board intermediate body 28 is a wiring main body layer 8a disposed in the opening 26 of the transfer plate 18, and has a fine first uneven structure 14 formed on the end surface exposed from the opening 26. 8a, and a protective layer 8b disposed over the end surface of the wiring body layer 8a exposed from the opening 26 and over an area of the transfer plate 18 other than the area of the opening 26. The thickness D1 of the protective layer 8b on the end surface of the wiring main body layer 8a is smaller than the thickness D2 of the protective layer 8b on other areas of the transfer plate 18.

According to this, in the process of manufacturing the mounting board 2, when the protective layer 8b exposed on the insulating layer 6 is etched with an etching liquid, the etching liquid is difficult to enter into the interface between the metal layer 8 and the insulating layer 6. Become. As a result, undercuts in the metal layer 8 can be reduced.

(Embodiment 2)
[2-1. Configuration of mounting board]
The configuration of the mounting board 2A according to the second embodiment will be described with reference to FIG. 6. FIG. 6 is a cross-sectional view of the mounting board 2A according to the second embodiment. In each of the following embodiments, the same components as in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted.

As shown in FIG. 6, a mounting board 2A according to the second embodiment is a semiconductor package board including, for example, a plurality of wiring layers on which wiring is formed. The mounting board 2A includes a support base material 30, an adhesive member 32, an insulating layer 6A, a plurality of metal layers 8, a via electrode 34, and a conductor 36.

The support base material 30 is a member that becomes the base of the mounting board 2A. The support base material 30 is made of an insulating material such as an insulating resin, and is arranged to face a motherboard (not shown).

The adhesive member 32 is arranged on the support base material 30. The adhesive member 32 is a member for bonding the support base material 30 and the insulating layer 6A together.

The insulating layer 6A is arranged above the support base material 30 via the adhesive member 32. A via hole 38 is formed in the insulating layer 6A. A via electrode 34 is arranged within the via hole 38 . The via hole 38 has a truncated conical shape with a tapered inner surface. One surface of the insulating layer 6A (the surface opposite to the supporting base material 30) has a first region 10 forming an interface with the metal layer 8 and a second region other than the first region 10. It includes a region 12. Similar to the first embodiment, the surface roughness of the first region 10 is greater than the surface roughness of the second region 12. Specifically, in the first region 10, a fine first uneven structure 14 is formed. Further, the second region 12 is formed in a flat shape, and no fine uneven structure is formed in the second region 12.

A plurality of metal layers 8 are arranged on the insulating layer 6A. Specifically, the plurality of metal layers 8 are arranged so as to be in contact with one surface of the insulating layer 6A, and are arranged above the support base material 30 via the insulating layer 6A and the adhesive member 32. . As in the first embodiment, each of the plurality of metal layers 8 includes a wiring main body layer 8a and a protective layer 8b. A fine second uneven structure 16 is formed on the end surface of the wiring body layer 8a (the surface on the side facing the first region 10 of the insulating layer 6A). The second uneven structure 16 has a shape corresponding to the first uneven structure 14 of the insulating layer 6A, and is fitted with the first uneven structure 14. Note that the plurality of metal layers 8 function as, for example, copper pillar bumps for electrically connecting an IC (Integrated Circuit) chip and the mounting board 2A.

At least a portion of the via electrode 34 is disposed within a via hole 38 in the insulating layer 6A. Specifically, the via electrode 34 is embedded in the via hole 38 without any gaps. Further, the via electrode 34 is arranged so as to protrude not only from the inside of the via hole 38 but also from the other surface (the surface on the supporting base material 30 side) of the insulating layer 6A. The via electrode 34 is electrically connected to the end surface of the wiring body layer 8a of one of the metal layers 8 through the protective layer 8b.

The conductor 36 is a wiring, an electrode, or the like formed in a wiring layer different from the metal layer 8. The conductor 36 is placed in contact with the other surface of the insulating layer 6A via the seed layer 40. Note that the seed layer 40 is a seed electrode made of a conductive material for forming the conductor 36 by electrolytic plating.

[2-2. Manufacturing method of mounting board]
A method for manufacturing the mounting board 2A according to the second embodiment will be described with reference to FIGS. 7A to 7C. 7A to 7C are diagrams for explaining a method of manufacturing the mounting board 2A according to the second embodiment.

First, the process of forming the first wiring layer will be described with reference to FIG. 7A. As shown in FIG. 7A (a), a production plate 42 (an example of a plate member) is prepared. The preparation plate 42 includes a base material 44, a seed layer 46, and an insulating layer 48. The base material 44 is made of, for example, a glass substrate or a metal substrate. The seed layer 46 is a seed electrode made of a conductive material for forming the wiring body layer 8a by electrolytic plating, and is disposed on the base material 44. Insulating layer 48 is disposed over seed layer 46 . The insulating layer 48 is made of, for example, insulating resin. A plurality of openings 50 are formed in the insulating layer 48 for forming the wiring main body layer 8a. The seed layer 46 is exposed in these plurality of openings 50.

Next, as shown in FIG. 7A (b), an electrolytic Cu plating film made of copper is formed on the seed layer 46 in the opening 50 of the insulating layer 48 of the preparation plate 42 by electrolytic plating. As a result, the wiring body layer 8a, which is an electrolytic Cu plating film, is formed on the seed layer 46 in the opening 50 of the insulating layer 48 of the production plate 42.

Next, as in the first embodiment, the end surface of the wiring main layer 8a exposed from the opening 50 of the insulating layer 48 of the preparation plate 42 is roughened by, for example, wet etching using an etching solution. As a result, a second uneven structure 16 is formed on the end face of the wiring main body layer 8a.

Finally, electroless plating is applied to the end face of the wiring body layer 8a exposed through the opening 50 of the insulating layer 48 of the production plate 42 and on the insulating layer 48 of the production plate 42 (that is, the insulating layer 48 An electroless Cu plating film made of copper is formed over an area other than the area of the opening 50). As a result, the protective layer 8b, which is an electroless Cu plating film, is formed over the end face of the wiring main layer 8a and over the insulating layer 48 of the preparation plate 42. At this time, the protective layer 8b on the end face of the wiring body layer 8a is formed in an uneven shape along the surface of the second uneven structure 16. Further, the protective layer 8b in the insulating layer 48 of the preparation plate 42 is formed flat along the surface of the insulating layer 48. As a result, as shown in FIG. 7A (b), the mounting board intermediate body 28 is formed on the production plate 42.

Next, a process for forming the second wiring layer will be described with reference to FIG. 7B. As shown in FIGS. 7B (a) and (b), the wiring main layer 8a and the protective layer 8b are transferred to one surface of the insulating layer 6A by using, for example, a transfer method as in the first embodiment. , the wiring body layer 8a and the protective layer 8b are formed on the insulating layer 6A. At this time, a via hole 38 is formed in the insulating layer 6A by removing a portion of the insulating layer 6A. For example, a portion of the insulating layer 6A can be removed by irradiating a laser beam from above the wiring main layer 8a, and the via hole 38 can be formed. By forming the via hole 38 in the insulating layer 6A in this manner, a portion of the protective layer 8b is exposed.

Next, as shown in FIG. 7B(c), an electroless Cu plating film made of copper is formed on the insulating layer 6A by electroless plating. Thereby, the seed layer 40, which is an electroless Cu plating film, is formed on the insulating layer 6A. Note that the seed layer 40 may be formed by sputtering instead of electroless plating.

Next, as shown in FIG. 7B(d), a resist 52 is selectively formed on the seed layer 40. A plurality of openings 54 are formed in the resist 52. The plurality of openings 54 expose predetermined regions of the seed layer 40 and the via holes 38 of the insulating layer 6A. That is, the via hole 38 of the insulating layer 6A communicates with the opening 54. As the resist 52, for example, a dry film resist (DFR) can be used.

Next, electrolytic plating made of copper is applied on the seed layer 40 in the opening 54 of the resist 52 and on the protective layer 8b in the opening 54 of the resist 52 and the via hole 38 of the insulating layer 6A. Form a Cu plating film. As a result, the conductor 36, which is an electrolytic Cu plating film, is formed on the seed layer 40 in the opening 54 of the resist 52. Furthermore, a via electrode 34, which is an electrolytic Cu plating film, is formed within the opening 54 of the resist 52 and on the protective layer 8b within the via hole 38 of the insulating layer 6A.

Next, as shown in FIG. 7B(e), the resist 52 is removed. Specifically, the resist 52, which is a dry film resist, is peeled off from the seed layer 40. This exposes the portion of the seed layer 40 that was covered with the resist 52.

Finally, as shown in FIG. 7B(f), the seed layer 40 exposed on the insulating layer 6A is etched with an etching solution using the conductor 36 as a mask. Thereby, the seed layer 40 exposed to the insulating layer 6A is removed.

Next, with reference to FIG. 7C, a process for processing the back surface (motherboard side surface) of the mounting board 2A will be described. First, as shown in FIG. 7C (a), the support base material 30 and the insulating layer 6A are bonded to each other via the adhesive member 32. Next, as shown in FIG. 7C (b), the preparation plate 42 is peeled off from the insulating layer 6A. Finally, as shown in FIG. 7C (c), the protective layer 8b exposed on the insulating layer 6A is etched with an etching solution using the plurality of wiring body layers 8a as a mask. As a result, the protective layer 8b exposed on the insulating layer 6A is removed, and a fine metal layer 8 composed of the wiring main layer 8a and the protective layer 8b is formed on the insulating layer 6A. In the manner described above, the mounting board 2A is manufactured.

[2-3. effect]
Also in this embodiment, the same effects as in the first embodiment can be obtained.

(Embodiment 3)
[3-1. Configuration of mounting board]
The configuration of the mounting board 2B according to the third embodiment will be described with reference to FIG. 8. FIG. 8 is a cross-sectional view of the mounting board 2B according to the third embodiment.

As shown in FIG. 8, in the mounting board 2B according to the third embodiment, the surface roughness of the first region 10 and the second region 12 of the insulating layer 6B are different from each other. Specifically, the surface roughness of the first region 10 is smaller than the surface roughness of the second region 12. More specifically, a fine first uneven structure 14 is formed in the first region 10, and a fine first uneven structure 56 is also formed in the second region 12. The surface roughness of the first uneven structure 14 (first region 10) is, for example, 10 nm to 300 nm in root mean square roughness Rq, more preferably 20 nm to 100 nm. On the other hand, the surface roughness of the first uneven structure 56 (second region 12) is, for example, larger than 300 nm in root mean square roughness Rq.

[3-2. Manufacturing method of mounting board]
A method for manufacturing the mounting board 2B according to the third embodiment will be described with reference to FIG. 9. FIG. 9 is a diagram for explaining a method for manufacturing the mounting board 2B according to the third embodiment.

First, as in the first embodiment, the steps (a) to (f) in FIG. 9 are executed. That is, the steps (a) to (f) in FIG. 9 are the same as the steps (a) to (f) in FIG. 3, respectively.

After the step of FIG. 9(f), as shown in FIG. 9(g), the exposed region (second region 12) of one surface of the insulating layer 6B is roughened by desmear treatment. . In the manner described above, the mounting board 2B is manufactured.

[3-3. effect]
In this embodiment, a fine first uneven structure 14 is formed in the first region 10, and a fine first uneven structure 56 is formed in the second region 12. The surface roughness of the first region 10 is smaller than the surface roughness of the second region 12.

According to this, as in the first embodiment, it is possible to improve the adhesion between the metal layer 8 and the insulating layer 6B, and it is also possible to improve the high frequency characteristics. Further, since the first uneven structure 56 is also formed in the second region 12, the anchor effect causes the insulating layer 6B and other layers formed on the insulating layer 6B (for example, an interlayer insulating layer, etc. ).

(Modified example)
Although the mounting board and the like according to the present disclosure have been described based on the above embodiments, the present disclosure is not limited to the above embodiments. A form obtained by making various modifications to each of the above embodiments that a person skilled in the art would think of, and a form realized by arbitrarily combining the constituent elements and functions of each embodiment without departing from the spirit of the present disclosure. are also included in this disclosure.

The mounting board according to the present disclosure can be applied, for example, as a semiconductor package board.

2, 2A, 2B, 100 Mounting board 4 Board 6, 6A, 6B, 24, 48, 102 Insulating layer 8 Metal layer 8a Wiring body layer 8b Protective layer 10 First region 12 Second region 14, 56 First Uneven structure 16 Second uneven structure 18 Transfer plate 20, 44 Base material 22, 46, 104 Seed layer 26, 50, 54, 106 Opening 28 Mounting board intermediate 30 Supporting base material 32 Adhesive member 34 Via electrode 36 Conductor 38 Via hole 40 Seed layer 42 Preparation plate 52, 108 Resist 110 Wiring layer pattern 112 Wiring layer

Claims (8)

an insulating layer;
a metal layer disposed so as to be in contact with one surface of the insulating layer,
The one surface of the insulating layer is
a first region forming an interface with the metal layer;
a second area other than the first area,
The surface roughness of the first region and the surface roughness of the second region are different from each other. Mounting board. The mounting board according to claim 1, wherein surface roughness of the first region is greater than surface roughness of the second region. A fine first uneven structure is formed in the first region,
The mounting board according to claim 2, wherein the second region is formed in a flat shape. A fine first uneven structure is formed in each of the first region and the second region,
The mounting board according to claim 1, wherein surface roughness of the first region is smaller than surface roughness of the second region. The metal layer is
a first metal layer formed with a second fine uneven structure having a shape corresponding to the first uneven structure, the second uneven structure fitting with the first uneven structure;
The mounting board according to claim 3 or 4, further comprising: a second metal layer interposed between the first uneven structure and the second uneven structure. The mounting board according to claim 5, wherein the second metal layer has a thickness smaller than a difference between a maximum height and a minimum height of the first uneven structure. preparing a transfer plate having an opening;
forming a metal body layer in the opening of the transfer plate;
Roughening the end surface of the metal body layer exposed from the opening;
A step of forming a metal layer including the metal body layer on the insulating layer by transferring the end surface of the metal body layer to one surface of the insulating layer using a transfer method. manufacturing method. A mounting board intermediate for forming a mounting board using a plate member having an opening,
a first metal layer disposed in the opening of the plate member, the first metal layer having a fine uneven structure formed on an end surface exposed from the opening;
a second metal layer disposed over the end surface of the first metal layer exposed from the opening and over an area other than the area of the opening of the plate member; Equipped with
The thickness of the second metal layer on the end surface of the first metal layer is smaller than the thickness of the second metal layer on the other region of the plate member. Mounting board intermediate .

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