JP2023052901A - Conductive substrate and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive substrate which suppresses peeling of a conductive layer, and a manufacturing method thereof.

SOLUTION: A conductive substrate 10 comprises: a substrate 12 including a first face 13 and a second face 14 which is opposite to the first face 13; a signal layer 311 which is positioned on the first face 13; and a ground layer 312 which is positioned on the first face 13 so as to be adjacent to the signal layer 311 while being spaced apart from each other and includes a plurality of projections 312a protruding in a plane direction along the first face 13 over a range of at least a part of an end 312c which is not opposed to the signal layer 311.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2023,JPO&INPIT

Description

TECHNICAL FIELD The present disclosure relates to conductive substrates and methods of manufacturing the same.

Conventionally, various techniques related to conductive substrates having conductive layers have been proposed. For example, Patent Literature 1 discloses a wiring board that includes a signal layer that transmits high-frequency signals and a ground layer that matches the characteristic impedance between the signal layer and the signal layer.

JP 2012-248797 A

The thickness of the conductive layer is desirably thick in order to transmit high-frequency signals with little loss. However, since the thickness of the conductive layer is large, the stress of the conductive layer increases, and there is a possibility that peeling of the conductive layer may occur. Specifically, conventionally, since the end portion of the conductive layer is formed in a shape that does not have unevenness, the stress of the conductive layer cannot be relieved at the end portion of the conductive layer, and the conductive layer is formed first from the end portion. There is a risk that the peeling of the coating will progress.

The present disclosure has been made in consideration of the above points, and an object thereof is to provide a conductive substrate capable of suppressing peeling of a conductive layer and a method for manufacturing the same.

In order to solve the above problems, in one aspect of the present disclosure,
a substrate having a first side and a second side opposite the first side;
a signal layer located on the first surface;
A plurality of polarizers located on the first surface adjacent to the signal layer at intervals and protruding in a plane direction along the first surface over at least a part of an end not facing the signal layer A ground layer having a protrusion is provided.

The plurality of protrusions may be periodically positioned along an edge of the ground layer not facing the signal layer.

The end of the ground layer not facing the signal layer may be an outer end of the ground layer.

The ground layer is provided with a through hole in a direction intersecting with the first surface,
The end of the ground layer not facing the signal layer may be the inner end of the through hole.

The ground layer may have a first ground layer positioned on the first surface so as to be adjacent to the signal layer with a space therebetween in the planar direction.

The ground layer may have a second ground layer positioned on the first surface so as to be adjacent to the signal layer with a gap therebetween in a first direction intersecting the first surface. .

The ground layer is positioned on the first surface so as to be adjacent to the signal layer with a space therebetween in a second direction opposite to the first direction in a direction crossing the first surface. It may have layers.

A second ground layer having a plurality of projections positioned on the first surface so as to be adjacent to the second ground layer with a space therebetween in the first direction and projecting in the surface direction over at least a part of the end portion. Four ground layers may also be provided.

A through electrode may be further provided which penetrates the substrate from the first surface to the second surface and is connected to the signal layer.

A capacitor may be further provided on the first surface and connected to the signal layer.

A first insulating layer may be further provided on the ground layer.

The first insulating layer may be in contact with the surface of the substrate that is in contact with the ground layer through the gaps between the plurality of protrusions.

The first surface of the substrate may be the surface in contact with the ground layer on the substrate side.

A surface of a second insulating layer located between the first surface of the substrate and the ground layer may be the surface of the substrate that contacts the ground layer.

In another aspect of the present disclosure,
providing a substrate having a first side and a second side opposite the first side;
forming a signal layer on the first surface;
A ground layer having a plurality of protrusions protruding in a plane direction along the first surface over at least a part of an end portion not facing the signal layer is spaced apart from the signal layer on the first surface. forming adjacent layers.

According to the present disclosure, peeling of the conductive layer can be suppressed.

It is a cross-sectional view showing a conductive substrate according to the present embodiment. 2 is a cross-sectional view taken along line II-II of FIG. 1 showing the conductive substrate according to the present embodiment; FIG. It is a top view which shows the conductive substrate by this embodiment. It is a sectional view showing a manufacturing method of a conductive board by this embodiment. FIG. 5 is a cross-sectional view showing the method for manufacturing the conductive substrate according to the embodiment following FIG. 4 ; FIG. 6 is a cross-sectional view showing the method for manufacturing the conductive substrate according to the embodiment following FIG. 5 ; FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6 showing the method for manufacturing the conductive substrate according to the present embodiment following FIG. 5; FIG. 8 is a cross-sectional view showing the method for manufacturing the conductive substrate according to the present embodiment following FIGS. 6 and 7; FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8 showing the method of manufacturing the conductive substrate according to the present embodiment following FIGS. 6 and 7; FIG. 10 is a cross-sectional view showing the method for manufacturing the conductive substrate according to the embodiment following FIGS. 8 and 9; FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 10 showing the method of manufacturing the conductive substrate according to the present embodiment following FIGS. 8 and 9; FIG. 12 is a cross-sectional view showing the method for manufacturing the conductive substrate according to the embodiment following FIGS. 10 and 11; FIG. 12 is a cross-sectional view taken along line XIII-XIII in FIG. 12, showing the method of manufacturing the conductive substrate according to the present embodiment following FIGS. 10 and 11; It is a sectional view showing a conductive board by the 1st modification of this embodiment. FIG. 15 is a cross-sectional view taken along line XV-XV of FIG. 14 showing a conductive substrate according to a first modification of the embodiment; FIG. 16 is a cross-sectional view taken along line XVI-XVI of FIG. 15 showing a conductive substrate according to a first modification of the embodiment; FIG. 16 is a cross-sectional view taken along line XVII-XVII of FIG. 15 showing a conductive substrate according to a first modified example of the present embodiment; FIG. 11 is a plan view showing a conductive substrate according to a second modification of the embodiment; FIG. 11 is an enlarged plan view showing a conductive substrate according to a third modification of the embodiment; It is a sectional view showing the conductive substrate by the 4th modification of this embodiment. FIG. 21 is a cross-sectional view taken along line XXI-XXI of FIG. 20 showing a conductive substrate according to a fourth modification of the embodiment; It is a sectional view showing the conductive substrate by the 5th modification of this embodiment. FIG. 23 is a cross-sectional view taken along line XXIII-XXIII of FIG. 22 showing a conductive substrate according to a fifth modification of the embodiment; FIG. 11 is a cross-sectional view showing a conductive substrate according to a sixth modification of the embodiment; FIG. 14 is a cross-sectional view showing a conductive substrate according to a seventh modification of the embodiment; FIG. 12 is a cross-sectional view showing a conductive substrate according to an eighth modification of the embodiment; It is a figure which shows the example of the product by which a conductive substrate is mounted.

Hereinafter, a configuration of a conductive substrate and a method for manufacturing the same according to embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments shown below are examples of the embodiments of the present disclosure, and the present disclosure should not be construed as being limited to these embodiments. Also, in this specification, terms such as "substrate", "base material", "sheet" and "film" are not to be distinguished from each other based only on the difference in designation. For example, "substrate" and "base material" are concepts that include members that can be called sheets and films. Furthermore, terms used herein to specify shapes and geometric conditions and their degrees, such as terms such as "parallel" and "perpendicular", length and angle values, etc., are bound by strict meanings. However, it is interpreted to include the extent to which similar functions can be expected. In addition, in the drawings referred to in this embodiment, the same reference numerals or similar reference numerals may be assigned to the same portions or portions having similar functions, and repeated description thereof may be omitted. Also, the dimensional ratios in the drawings may differ from the actual ratios for convenience of explanation, and some of the configurations may be omitted from the drawings.

conductive substrate 10
Embodiments of the present disclosure will be described below. First, the configuration of the conductive substrate according to this embodiment will be described. The conductive substrate of this embodiment can be used, for example, as an interposer substrate that transmits high-frequency signals. FIG. 1 is a cross-sectional view showing a conductive substrate 10 according to this embodiment. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1 showing the conductive substrate 10 according to this embodiment. FIG. 3 is a plan view showing the conductive substrate 10 according to this embodiment.

As shown in FIGS. 1 to 3, the conductive substrate 10 includes a substrate 12, a through electrode 22, a first wiring structure portion 30, a second wiring structure portion 40, and an organic layer . Each component of the conductive substrate 10 will be described below.

(substrate 12)
Substrate 12 includes a first side 13 and a second side 14 opposite first side 13 . Further, the substrate 12 is provided with a plurality of through holes 20 penetrating from the first surface 13 to the second surface 14 .

Substrate 12 includes an inorganic material having a certain insulating property. For example, the substrate 12 may be a glass substrate, a quartz substrate, a sapphire substrate, a resin substrate, a silicon substrate, a silicon carbide substrate, an alumina (Al ₂ O ₃ ) substrate, an aluminum nitride (AlN) substrate, a zirconia oxide (ZrO ₂ ) substrate, etc. Alternatively, these substrates are laminated. The substrate 12 may partially include a substrate made of a conductive material such as an aluminum substrate or a stainless steel substrate.

Examples of the glass used for the substrate 12 include alkali-free glass. Alkali-free glass is glass that does not contain alkaline components such as sodium and potassium. Alkali-free glass includes, for example, boric acid instead of an alkaline component. Alkali-free glass also contains, for example, alkaline earth metal oxides such as calcium oxide and barium oxide.

In the example shown in FIG. 1, the through hole 20 formed in the substrate 12 has a shape whose width decreases from the first surface 13 and the second surface 14 of the substrate 12 toward the central portion in the thickness direction of the substrate 12. ing. However, the shape of through-hole 20 is not particularly limited. For example, the sidewall 21 of the through hole 20 may extend along the normal direction of the first surface 13 of the substrate 12 . Moreover, a part of the side wall 21 may be curved.

(Through electrode 22)
The through electrode 22 is a member positioned inside the through hole 20 and having conductivity. In the present embodiment, the thickness of the through electrode 22 is smaller than the width of the through hole 20, so that there is a space inside the through hole 20 where the through electrode 22 does not exist. That is, the through electrode 22 is a so-called conformal via. In the example of FIG. 1, the space inside the through-hole 20 is filled with an organic layer 26 located inside the through-electrode 22 .

The configuration of the through electrode 22 is not particularly limited as long as the through electrode 22 has conductivity. For example, the through electrode 22 may be composed of a single conductive layer, or may include a plurality of conductive layers. Also, the through electrode 22 may include a seed layer and a plating layer that are arranged in order from the side wall 21 side of the through hole 20 to the center side. In this case, an intermediate layer may be provided between the sidewall 21 of the through hole 20 and the seed layer. As a material forming the intermediate layer, for example, titanium, titanium nitride, molybdenum, molybdenum nitride, tantalum, tantalum nitride, etc., or a laminate thereof can be used. The intermediate layer is formed, for example, by a physical film-forming method such as a vapor deposition method or a sputtering method. The intermediate layer serves, for example, to enhance the adhesion of the seed layer or plating layer to the sidewalls 21 . The intermediate layer may also play a role of suppressing the diffusion of metal elements contained in the seed layer or the plating layer into the substrate 12 through the sidewalls 21 of the through holes 20 .

Organic layer 26 preferably comprises an organic material having a dielectric loss tangent of 0.003 or less, more preferably 0.002 or less, and even more preferably 0.001 or less. As an organic material for the organic layer 26, polyimide, epoxy, or the like can be used. By configuring the organic layer 26 using an organic material with a small dielectric loss tangent, it is possible to suppress part of the electrical signal that should pass through the through electrode 22 from passing through the organic layer 26 . Thereby, the band of the conductive substrate 10 can be widened to the high frequency side.

(First wiring structure portion 30)
Next, the first wiring structure portion 30 will be described. The first wiring structure portion 30 has layers such as a conductive layer and an insulating layer provided on the first surface 13 side of the substrate 12 so as to configure an electrical circuit on the first surface 13 side of the substrate 12 . In the example of FIG. 1 , the first wiring structure 30 has a first surface first conductive layer 31 .

[First surface first conductive layer 31]
The first surface first conductive layer 31 is a conductive layer located on the first surface 13 of the substrate 12 . The first surface first conductive layer 31 is connected to the through electrode 22 . The first surface first conductive layer 31 has a coplanar line in which a signal line and a ground are arranged on the same surface. Specifically, as shown in FIGS. 2 and 3, the coplanar line has a signal layer 311 and a ground layer 312 that is an example of a first ground layer.

[Signal layer 311]
More specifically, as shown in FIGS. 1 to 3, the signal layer 311 is made up of a portion of the first surface first conductive layer 31 . The signal layer 311 transmits electrical signals such as high frequency signals. Note that the high-frequency signal includes, for example, an electric signal of 0.1 GHz or higher. The signal layer 311 is located on the first surface 13 and extends in the extension direction D11 in FIG. 1 as an example of a planar direction along the first surface 13 . In the example of FIG. 1, the signal layer 311 is connected to one through electrode 22 at one end in the extending direction D11, and is connected to another through electrode 22 at the other end in the extending direction D11.

The thickness of the signal layer 311 is preferably 5 μm or more. Since the conductor resistance loss of the signal layer 311 can be reduced by setting the thickness of the signal layer 311 to 5 μm or more, the signal transmission loss can be suppressed. More preferably, the thickness of the signal layer 311 is 20 μm or less. By setting the thickness of the signal layer 311 to 20 μm or less, interfacial stress between the signal layer 311 and the first surface 13 can be suppressed, so peeling of the signal layer 311 can be suppressed.

The dimension of the signal layer 311 in the width direction D12 orthogonal to the extending direction D11 indicated by symbol W in FIG. 3, that is, the wiring width W may be 300 μm or less.

[Ground layer 312]
As shown in FIGS. 1 to 3, the ground layer 312 is made up of part of the first surface first conductive layer 31 . The ground layer 312 is connected to a reference potential such as ground potential and controls the characteristic impedance with the signal layer 311 . The ground layer 312 is positioned on the first surface 13 so as to be adjacent to the signal layer 311 with a gap in the width direction D<b>12 , which is an example of the surface direction along the first surface 13 . Ground layer 312 has a larger total area than signal layer 311 . In the example of FIG. 3, the ground layer 312 has a shape that sandwiches the signal layer 311 from both width directions D12. In order to control the characteristic impedance between the signal layer 311 and the signal layer 311 to a desired value, the ground layer 312 and the signal layer 311 have a predetermined distance d in the width direction D12.

The ground layer 312 has a plurality of protrusions 312 a that protrude in the plane direction over at least a part of the end that does not face the signal layer 311 . In the example of FIG. 3, the convex portion 312a protrudes outward in the direction opposite to the signal layer 311 in the width direction D12, that is, from the outer end portion 312c opposite to the inner end portion 312b of the ground layer 312 facing the signal layer 311. ing.

Further, in the example of FIG. 3, the convex portion 312a has a rectangular shape having long sides parallel to the width direction D12 and short sides parallel to the stretching direction D11. For example, the projection 312a may have a long side of 200 μm and a short side of 100 μm.

Also, in the example of FIG. 3 , the convex portions 312 a are periodically positioned over the outer end portion 312 c of the ground layer 312 . That is, the convex portions 312a are positioned at regular intervals in the extending direction D11. In other words, the ground layer 312 has a comb-tooth shape with a plurality of periodically positioned convex portions 312a. The dimension of the gap between the adjacent protrusions 312a may be, for example, 30 μm or more. By setting the dimension of the gaps between the protrusions 312a to 30 μm or more, the gaps can be formed with high dimensional accuracy using a resist, so that dimensional errors of the protrusions 312a can be suppressed.

As shown in FIGS. 1 and 3 , the first surface first conductive layer 31 including the signal layer 311 and the ground layer 312 has a seed layer 221 and a plating layer 222 . A seed layer 221 is located on the first surface 13 of the substrate 12 . A plating layer 222 is located on the seed layer 221 .

The seed layer 221 is a conductive layer that serves as a base for depositing metal ions in the plating solution and growing the plating layer 222 during the electroplating process for forming the plating layer 222 by electroplating. be. As a material for the seed layer 221, a conductive material such as copper can be used. The material of the seed layer 221 may be the same as or different from the material of the plating layer 222 . For example, the seed layer 221 may be a laminated film in which titanium and copper are laminated in order, chromium, or the like. The seed layer 221 may be formed by, for example, a sputtering method, a vapor deposition method, an electroless plating method, or the like.

The plating layer 222 is a conductive layer formed by plating. The plating layer 222 contains copper. The plating layer 222 may contain alloys of copper and metals other than copper, such as gold, silver, platinum, rhodium, tin, aluminum, nickel, and chromium, or copper and metals other than copper. may be laminated.

(Second wiring structure portion 40)
Next, the second wiring structure portion 40 will be described. The second wiring structure portion 40 has layers such as a conductive layer and an insulating layer provided on the second surface 14 side of the substrate 12 so as to form an electrical circuit on the second surface 14 side. In the example of FIG. 1 , the second wiring structure 40 has a second surface first conductive layer 41 .

[Second surface first conductive layer 41]
The second surface first conductive layer 41 is a conductive layer located on the second surface 14 of the substrate 12 . The second surface first conductive layer 41 may be connected to the through electrode 22 . The second surface first conductive layer 41 includes a seed layer 221 and a plating layer 222 that are laminated in order on the second surface 14 of the substrate 12, like the through electrodes 22 and the first surface first conductive layer 31. You can stay. The material forming the second surface first conductive layer 41 is the same as the material forming the through electrode 22 .

Method for Manufacturing Conductive Substrate 10 An example of a method for manufacturing the conductive substrate 10 will be described below with reference to FIGS. 4 to 13. FIG.

(Through hole forming step)
FIG. 4 is a cross-sectional view showing a method of manufacturing the conductive substrate 10 according to this embodiment. First, the substrate 12 is prepared. Next, a resist layer is provided on at least one of the first surface 13 and the second surface 14 . After that, openings are provided in the resist layer at positions corresponding to the through holes 20 . Next, by processing the substrate 12 in the openings of the resist layer, through holes 20 can be formed in the substrate 12 as shown in FIG. As a method for processing the substrate 12, a dry etching method such as a reactive ion etching method or a deep reactive ion etching method, a wet etching method, or the like can be used.

The through holes 20 may be formed in the substrate 12 by irradiating the substrate 12 with a laser. In this case, the resist layer may not be provided. As a laser for laser processing, an excimer laser, Nd:YAG laser, femtosecond laser, or the like can be used. When an Nd:YAG laser is employed, a fundamental wave with a wavelength of 1064 nm, a second harmonic with a wavelength of 532 nm, a third harmonic with a wavelength of 355 nm, or the like can be used.

Alternatively, laser irradiation and wet etching can be combined as appropriate. Specifically, first, an altered layer is formed in a region of the substrate 12 where the through hole 20 is to be formed by laser irradiation. Subsequently, the substrate 12 is immersed in hydrogen fluoride or the like to etch the altered layer. Through holes 20 can thus be formed in the substrate 12 . Alternatively, the through holes 20 may be formed in the substrate 12 by blasting the substrate 12 with an abrasive.

By processing the substrate 12 from both the first surface 13 side and the second surface 14 side, a through hole 20 having a shape whose width decreases toward the central portion in the thickness direction of the substrate 12 shown in FIG. 4 is formed. can do.

(Formation process of through electrode, signal layer, and ground layer)
5A to 5D are cross-sectional views showing the method for manufacturing the conductive substrate 10 according to the present embodiment following FIG. After forming the through hole 20, the through electrode 22 is formed on the side wall 21 of the through hole 20, as shown in FIG. Specifically, the seed layer 221 is formed on the first surface 13, the second surface 14, and the sidewalls 21 of the substrate 12 by sputtering, vapor deposition, electroless plating, or the like.

FIG. 6 is a cross-sectional view showing the manufacturing method of the conductive substrate 10 according to this embodiment following FIG. FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 6, showing the method of manufacturing the conductive substrate 10 according to this embodiment following FIG. After forming the seed layer 21, a resist layer 37 is partially formed on the seed layer 221 as shown in FIGS.

FIG. 8 is a cross-sectional view showing the method for manufacturing the conductive substrate 10 according to the present embodiment following FIGS. 6 and 7. FIG. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8 showing the manufacturing method of the conductive substrate 10 according to this embodiment following FIGS. After forming the resist layer 37, as shown in FIGS. 8 and 9, a plating layer 222 is formed on the seed layer 221 not covered with the resist layer 37 by electrolytic plating using the resist layer 37 as a mask.

10A and 10B are cross-sectional views showing the method for manufacturing the conductive substrate 10 according to the present embodiment following FIGS. 8 and 9. FIG. FIG. 11 is a cross-sectional view taken along the line XI-XI in FIG. 10, showing the method of manufacturing the conductive substrate 10 according to this embodiment following FIGS. After forming the plating layer 222, the resist layer 37 is removed as shown in FIGS.

12A and 12B are cross-sectional views showing the method for manufacturing the conductive substrate 10 according to the present embodiment following FIGS. FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. 12, showing the method of manufacturing the conductive substrate 10 according to this embodiment following FIGS. 10 and 11. FIG. After removing the resist layer 37, as shown in FIGS. 10 and 11, the portion of the seed layer 221 where the resist layer 37 was formed is removed by wet etching.

Through the above steps, the through electrode 22, the first surface first conductive layer 31 including the signal layer 311 and the ground layer 312, and the second surface first conductive layer 41 can be formed. Note that a step of annealing the plating layer 222 may be performed.

The effects brought about by this embodiment will be described below.

As shown in FIGS. 2 and 3, the conductive substrate 10 of this embodiment has a plurality of protrusions 312a on the outer end 312c of the ground layer 312. As shown in FIGS. Here, in order to suppress signal transmission loss due to the signal layer 311, it is preferable to increase the thickness of the signal layer 311. FIG. When the thickness of the signal layer 311 is increased, the thickness of the ground layer 312 formed in the same process as the signal layer 311 is also increased. If a thick ground layer is formed in a shape in which there is no gap between the convex portions 312a of the ground layer 312, the interfacial stress of the ground layer with respect to the first surface 13 of the substrate 12 increases, and the outer end portion of the ground layer increases. , there is a risk that the ground layer will peel off.

In contrast, according to the present embodiment, the ground layer 312 is shaped to have the protrusions 312a at the outer ends 312c. can be mitigated. As a result, peeling of the ground layer 312 at the outer end portion 312c can be suppressed.

Further, in this embodiment, the inner end portion 312b of the ground layer 312 facing the signal layer 311 is not provided with the convex portion 312a. Thereby, as shown in FIG. 3, a suitable distance d for controlling characteristic impedance can be secured between the ground layer 312 and the signal layer 311 .

(First modification)
Next, a first modification including a ground layer having a first ground layer and a second ground layer, a conductive layer, a first insulating layer, and a second insulating layer will be described.

FIG. 14 is a cross-sectional view showing a conductive substrate 10 according to a first modified example of this embodiment. FIG. 15 is a cross-sectional view taken along the line XV-XV of FIG. 14 showing the conductive substrate 10 according to the first modified example of this embodiment. FIG. 16 is a cross-sectional view taken along line XVI-XVI in FIG. 15 showing the conductive substrate 10 according to the first modification of the present embodiment. FIG. 17 is a cross-sectional view taken along line XVII-XVII of FIG. 15, showing the conductive substrate 10 according to the first modification of the present embodiment.

(First wiring structure portion 30)
In addition to the first surface first conductive layer 31 described in the example of FIG. , a first surface first organic layer 34 , a first surface third conductive layer 35 which is an example of a conductive layer, and a first surface second organic layer 36 . The first surface first organic layer 34 is an example of a first insulating layer for the ground layer 312 and an example of a second insulating layer for the first surface second organic layer 36 . The first surface second organic layer 36 is an example of a first insulating layer for the first surface second conductive layer 33 .

[First surface second conductive layer 33]
The first surface second conductive layer 33 is formed on the first surface so as to be adjacent to the signal layer 311 with a gap in the upward direction D31 in FIG. 13 is a conductive layer. The first surface second conductive layer 33 functions as a second ground layer that controls the characteristic impedance with the signal layer 311 .

The first surface second conductive layer 33 is located on the first surface first organic layer 34 . The thickness of the first surface second conductive layer 33 may be the same as or different from the thickness of the first surface first conductive layer 31 .

As shown in FIGS. 15 and 17, the first-surface second conductive layer 33 has a plurality of protrusions 33a projecting outward in the width direction D12 from the outer end 33b in the width direction D12. The convex portions 33a are periodically positioned at the outer end portion 33b along the extending direction D11. The dimensions of the projections 33a of the first surface second conductive layer 33 may be the same as or different from the dimensions of the projections 312a of the ground layer 312 .

The first surface second conductive layer 33 may include a seed layer and a plated layer that are laminated in order on the first surface first organic layer 34 in the same manner as the through electrode 22 and the first surface first conductive layer 31. good. The material forming the first surface second conductive layer 33 is the same as the material forming the through electrode 22 and the first surface first conductive layer 31 .

[First surface first organic layer 34]
The first surface first organic layer 34 is a layer that is located on the first surface 13 or the first surface first conductive layer 31, contains an organic material, and has insulating properties.

The first surface first organic layer 34 and the other organic layers 36, 42, 44 preferably comprise an organic material having a dielectric loss tangent of 0.003 or less, more preferably 0.002 or less, and even more preferably 0.001 or less. include. As an organic material for the organic layers 34, 36, 42, 44, polyimide, epoxy resin, or the like can be used. By configuring the organic layer 34 using an organic material with a small dielectric loss tangent, it is possible to suppress part of the electrical signal that should pass through the signal layer 311 from passing through the organic layers 34 , 36 , 42 and 44 . . Thereby, the band of the conductive substrate 10 can be widened to the high frequency side.

The organic layers 34, 36, 42, and 44 may be formed, for example, by exposure processing and development processing using a photosensitive film containing an organic material, or by spin coating a liquid containing an organic material. It may be formed by coating and drying.

As shown in FIG. 16 , the first surface first organic layer 34 is in contact with the side wall of the first surface second conductive layer 33 between the convex portions 312 a of the ground layer 312 . Also, the first surface first organic layer 34 is in contact with the first surface 13 that is in contact with the ground layer 312 on the substrate 12 side through the gaps between the convex portions 312a.

[First surface third conductive layer 35]
The first-surface third conductive layer 35 is adjacent to the first-surface second conductive layer 33, ie, the second ground layer, with a space therebetween in the upward direction D31 in FIG. It is a layer located on the substrate 12 to match. The first surface third conductive layer 35 may function as a fourth ground layer.

The first surface third conductive layer 35 is located on the first surface second organic layer 36 . The thickness of the first surface third conductive layer 35 may be the same as or different from the thickness of the first surface first conductive layer 31 .

Similar to the first-surface second conductive layer 33, the first-surface third conductive layer 35 has a plurality of protrusions 35a projecting outward in the width direction D12 from the outer end portion 35b in the width direction D12. The convex portions 35a are periodically positioned at the outer end portion 35b along the extending direction D11. The dimensions of the projections 35a of the first surface third conductive layer 35 may be the same as or different from the dimensions of the projections 312a of the ground layer 312 .

The first-surface third conductive layer 35 may include a seed layer and a plating layer that are laminated in order, similar to the through electrodes 22 and the first-surface first conductive layer 31 . The material forming the first surface third conductive layer 35 is the same as the material forming the through electrode 22 and the first surface first conductive layer 31 .

[First surface second organic layer 36]
The first surface second organic layer 36 is located on the first surface first organic layer 34 and the first surface third conductive layer 35, and is a layer containing an organic material and having insulating properties.

As shown in FIG. 17, the first surface second organic layer 36 is in contact with the side walls of the first surface second conductive layer 33 between the protrusions 33a of the first surface second conductive layer 33 . Also, the first surface second organic layer 36 is in contact with the surface of the first surface first organic layer 34 that is in contact with the first surface second conductive layer 33 on the substrate 12 side through the gaps between the protrusions 33a.

(Second wiring structure portion 40)
In addition to the second surface first conductive layer 41 described in the example of FIG. It comprises a layer 43 , a second surface second organic layer 44 and a second surface third electrode layer 45 .

[Second surface first organic layer 42]
The second surface first organic layer 42 is a layer that is located on the second surface first conductive layer 41 and the second surface 14 of the substrate 12, contains an organic material, and has insulating properties.

[Second surface second electrode layer 43]
The second surface second electrode layer 43 is a conductive layer located on the second surface first conductive layer 41 or on the second surface first organic layer 42 . The second-surface second electrode layer 43 may include a seed layer 221 and a plating layer 222 that are laminated in order on the second-surface first organic layer 42 in the same manner as the second-surface first conductive layer 41 . The material forming the second surface second electrode layer 43 is the same as the material forming the second surface first conductive layer 41 .

[Second surface second organic layer 44]
The second surface second organic layer 44 is a layer that is located on the second surface first organic layer 42 and the second surface second electrode layer 43, contains an organic material, and has insulating properties.

[Second surface third electrode layer 45]
The second surface third electrode layer 45 is a conductive layer located on the second surface second electrode layer 43 or on the second surface second organic layer 44 . The second surface third electrode layer 45 may include a seed layer 221 and a plating layer 222 that are laminated in order on the second surface second organic layer 44 . The material forming the second surface third electrode layer 45 is the same as the material forming the second surface first conductive layer 41 .

As shown in FIGS. 14 and 15, in the first modification, three conductive layers, a ground layer 312, a first surface second conductive layer 33, and a first surface third conductive layer 35, They overlap each other in the thickness direction D3 with the surface first organic layer 34 and the first surface second organic layer 36 interposed therebetween. Since the conductive layers 312 , 33 , 35 overlap each other, the thicknesses of the conductive layers 312 , 33 , 35 and the thicknesses of the conductive layers 312 , 33 , 35 and the organic layers 34 , 36 are different at the ends of the conductive layers 312 , 33 , 35 . The interfacial stress due to the difference in thermal expansion coefficient between the two layers increases, and the conductive layers 312, 33, and 35 may peel off.

On the other hand, in the first modification, since the projections 312a, 33a, 35a are provided at the outer ends of the respective conductive layers 3121, 33, 35, the interfacial stress can be relieved, Delamination of layers 312, 33, and 35 can be suppressed.

In addition, in the first modification, the contact area between the ground layer 312 and the first surface first organic layer 34 covering the ground layer 312 is increased on the side wall of the convex portion 312a of the ground layer 312 . As a result, the adhesive force between the ground layer 312 and the first surface first organic layer 34 can be increased, so that peeling of the ground layer 312 can be suppressed more effectively.

In addition, in the first modification, since the first surface first organic layer 34 is in contact with the first surface 13 of the substrate 12 through the convex portions 312a of the ground layer 312, the first surface first organic layer 34 and the first surface first organic layer 34 are in contact with the first surface 13 of the substrate 12. The contact area with the first surface 13 is large. As a result, the adhesive force between the first surface first organic layer 34 and the first surface 13 can be increased, so that the ground layer 312 sandwiched between the first surface first organic layer 34 and the first surface 13 is Peeling can be suppressed more effectively.

In addition, in the first modification, on the side wall of the convex portion 33a of the first surface second conductive layer 33, the first surface second conductive layer 33 and the first surface second conductive layer 33 covering the first surface second conductive layer 33 The contact area with the organic layer 36 is increased. As a result, the adhesive strength between the first surface second conductive layer 33 and the first surface second organic layer 36 can be increased, so that peeling of the first surface second conductive layer 33 can be suppressed more effectively. can be done.

In addition, in the first modification, since the first surface second organic layer 36 is in contact with the surface of the first surface first organic layer 34 through the protrusions 33a of the first surface second conductive layer 33, the first surface The contact area between the surface first organic layer 34 and the first surface second organic layer 36 is large. As a result, the adhesive force between the first surface first organic layer 34 and the first surface second organic layer 36 can be increased, so that the first surface first organic layer 34 and the first surface second organic layer 36 It is possible to more effectively suppress peeling of the first surface second conductive layer 33 sandwiched between the two.

(Second modification)
Next, a second modification in which through holes are provided in the second conductive layer will be described. FIG. 18 is a plan view showing a conductive substrate 10 according to a second modified example of this embodiment.

As shown in FIG. 18, in the second modification, the first-surface second conductive layer 33 is provided with through holes 33d in the thickness direction D3, which is the direction perpendicular to the paper surface of FIG.

According to the second modification, by providing the through hole 33d in the first surface second conductive layer 33, the contact area between the first surface second conductive layer 33 and the first surface second organic layer 36 and the The contact area between the first surface first organic layer 34 and the first surface second organic layer 36 can be increased. In addition, since the gas generated in the first surface first organic layer 34 can be released through the through holes 33d, the gas accumulated at the interface between the first surface first organic layer 34 and the first surface second conductive layer 33 can be released. , it is possible to suppress the application of stress upward D31 to the first surface second conductive layer 33 . As a result, peeling of the first surface second conductive layer 33 can be more effectively suppressed.

Note that the through holes may be provided in the first surface third conductive layer 35 . By providing the through holes in the first surface third conductive layer 35, peeling of the first surface third conductive layer 35 can be more effectively suppressed.

(Third modification)
Next, a third modification will be described in which a projection is provided at the end of the through-hole of the second conductive layer. FIG. 19 is an enlarged plan view showing a conductive substrate 10 according to a third modified example of this embodiment.

As shown in FIG. 19, the conductive substrate 10 of the third modified example has an inner end portion 33e of a through hole 33d provided in the first surface second conductive layer 33, and a surface direction along the first surface 13. It has a plurality of protrusions 33a.

According to the third modification, the contact area between the first surface second conductive layer 33 and the first surface second organic layer 36 is further increased by providing the convex portion 33a also at the inner end portion 33e of the through hole 33d. You can make it bigger. As a result, peeling of the first surface second conductive layer 33 can be more effectively suppressed.

(Fourth modification)
Next, a fourth modification in which the first surface second conductive layer 33 constitutes a coplanar line will be described. FIG. 20 is a cross-sectional view showing a conductive substrate 10 according to a fourth modified example of this embodiment. FIG. 21 is a cross-sectional view taken along line XXI-XXI in FIG. 20, showing the conductive substrate 10 according to a fourth modification of the present embodiment.

In the first modified example, the first surface first conductive layer 31 of the three conductive layers 31, 33, and 35 on the substrate 12 constitutes a coplanar line. On the other hand, in the fourth modification, the first surface second conductive layer 33 constitutes a coplanar line.

Specifically, as shown in FIGS. 20 and 21, the first surface second conductive layer 33 has a signal layer 331 and a ground layer 332 adjacent to the signal layer 331 with a gap in the width direction D12. . As shown in FIG. 20, the signal layer 331 penetrates the first surface first organic layer 34 and is connected to the through electrode 22 . As shown in FIG. 21, at the outer end of the ground layer 332, a plurality of protrusions 332a protruding outward in the width direction D12 are periodically arranged along the stretching direction D11, which is the direction perpendicular to the plane of FIG. is located

The first surface first conductive layer 31 is a third ground located on the first surface 13 so as to be adjacent to the signal layer 331 with a gap in the downward direction, which is an example of the second direction intersecting the first surface 13 . It may function as a layer. The first surface third conductive layer 35 may function as a second ground layer.

According to the fourth modification, even when the first-surface second conductive layer 33 constitutes a coplanar line, the convex portion 332a can suppress separation of the ground layer 332 .

(Fifth Modification)
Next, a fifth modification in which the first surface third conductive layer 35 constitutes a coplanar line will be described. FIG. 22 is a cross-sectional view showing a conductive substrate 10 according to a fifth modified example of this embodiment. FIG. 23 is a cross-sectional view taken along line XXIII-XXIII in FIG. 22, showing the conductive substrate 10 according to a fifth modification of the present embodiment.

In the fifth modification, the first surface third conductive layer 35 constitutes a coplanar line. Specifically, as shown in FIGS. 22 and 23, the first surface third conductive layer 35 has a signal layer 351 and a ground layer 352 adjacent to the signal layer 351 with a gap in the width direction D12. . As shown in FIG. 22 , the signal layer 351 penetrates the first surface first organic layer 34 and the first surface second organic layer 36 and is connected to the through electrode 22 . As shown in FIG. 23, on the outer end of the ground layer 352, a plurality of protrusions 352a protruding outward in the width direction D12 are periodically arranged along the stretching direction D11, which is the direction perpendicular to the plane of FIG. is located

According to the fifth modification, even when the first-surface third conductive layer 35 constitutes a coplanar line, the convex portion 352a can suppress separation of the ground layer 352 .

(Sixth modification)
Next, a sixth modification having a strip line in which the front and back sides of the signal line are sandwiched between ground planes via an insulating layer will be described. FIG. 24 is a cross-sectional view showing a conductive substrate 10 according to a sixth modification of this embodiment.

So far, an example has been described in which one of the three conductive layers 31, 33, and 35 on the substrate 12 constitutes a coplanar line. On the other hand, in the sixth modification, three conductive layers 31 , 33 , 35 on the substrate 12 form a strip line.

Specifically, as shown in FIG. 24, the conductive substrate 10 has a signal layer 311, and a first surface first conductive layer 31 and a first surface third conductive layer 35 functioning as ground layers. . A plurality of protrusions 31a and 35a protruding outward in the width direction D12 are formed on the outer ends of the first surface first conductive layer 31 and the first surface third conductive layer 35 in the direction perpendicular to the paper surface of FIG. are periodically located along the stretching direction D11.

According to the sixth modification, the characteristic impedance between the signal layer 311 and the ground layers 31 and 35 is controlled by the line width of the signal layer 311 and the thickness of the organic layers 34 and 36 by having the strip line. be able to. Also, by using the strip line, noise characteristics can be improved compared to the case of using the coplanar line. In addition, by having the convex portions 31a and 35a, it is possible to suppress the peeling of the ground layers 31 and 35 even when forming a strip line.

(Seventh Modification)
Next, a seventh modification having a differential transmission line that transmits one piece of data using two signal lines will be described. FIG. 25 is a cross-sectional view showing a conductive substrate 10 according to a seventh modified example of this embodiment.

So far, an example of the conductive substrate 10 provided with a single-ended coplanar line or stripline for transmitting one data with one signal line has been described. In contrast, the conductive substrate 10 of the seventh modified example has differential transmission lines.

Specifically, as shown in FIG. 25, the first surface second conductive layer 33 includes a first signal layer 311A and a second signal layer 311B spaced apart in the width direction D12, a signal layer 311A, and a ground layer 332 spaced outward in the width direction D12 with respect to 311B. The first signal layer 311A and the second signal layer 311B divide and transmit one electrical signal. The first surface first conductive layer 31 and the first surface third conductive layer 35 may function as ground layers.

In addition, a plurality of protrusions 31a, 332a protruding outward in the width direction D12 are provided at the outer ends of the first surface first conductive layer 31, the ground layer 332, and the first surface third conductive layer 35. 35a are periodically positioned along the stretching direction D11, which is the direction perpendicular to the plane of FIG.

According to the seventh modification, a signal waveform can be formed with a small voltage by having differential transmission lines. Since the signal waveform can be formed with a small voltage, the rise time of the signal can be shortened. Since the rise time of the signal can be shortened, high-frequency electrical signals can be transmitted appropriately compared to the single-ended method. In addition, since the projections 31a, 332a, and 35a are provided, the separation of the ground layers 31, 332, and 35 can be suppressed even when a differential transmission line is formed.

(Eighth modification)
Next, an eighth modified example having a capacitor will be described. FIG. 26 is a cross-sectional view showing a conductive substrate 10 according to an eighth modification of this embodiment.

As shown in FIG. 26 , in the eighth modification, a portion of the signal layer 311 is composed of the dielectric 32 located on the signal layer 311 and the first surface second conductive layer 33 located on the dielectric 32 . , constitute a capacitor 15 of MIM (Metal-Insulator-Metal) structure. Dielectric 32 contains, for example, a silicon nitride such as SiN.

Various modifications can be made to the above-described embodiment. Modifications will be described below with reference to the drawings as necessary. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding portions in the above-described embodiment are used for the parts that can be configured in the same manner as in the above-described embodiment, Duplicate explanations are omitted. Further, when it is clear that the effects obtained in the above-described embodiment can also be obtained in the modified example, the explanation thereof may be omitted.

Examples of Products to which Conductive Electrode Substrates Can Be Mounted FIG. 27 is a diagram illustrating examples of products to which the conductive substrates 10 according to embodiments of the present disclosure can be mounted. Conductive substrates 10 according to embodiments of the present disclosure may be utilized in a variety of products. For example, it is installed in a notebook personal computer 110, a tablet terminal 120, a mobile phone 130, a smart phone 140, a digital video camera 150, a digital camera 160, a digital clock 170, a server 180, and the like.

10 conductive substrate 12 substrate 311 signal layer 312 ground layer 312a convex portion

Claims (8)

a substrate having a first surface and a second surface opposite to the first surface, and provided with a through hole penetrating from the first surface to the second surface;
a through electrode located inside the through hole, having a seed layer containing copper and a plating layer in order from the side wall side to the center side of the through hole, and having a space in which the plating layer does not exist;
an organic layer positioned on the first surface so as to fill a space inside the through electrode;
a signal layer located on the organic layer and connected to the through electrode through the organic layer;
A plurality of protrusions located on the organic layer so as to be adjacent to the signal layer with a space therebetween and protruding in a planar direction along the first surface over at least a part of an end portion not facing the signal layer. a ground layer having a portion;
a second organic layer positioned on the ground layer and on the signal layer so as to be in contact with the organic layer through gaps between the plurality of protrusions of the ground layer. a substrate having a first surface and a second surface opposite to the first surface, and provided with a through hole penetrating from the first surface to the second surface;
a through electrode located inside the through hole, having a seed layer containing copper and a plating layer in order from the side wall side to the center side of the through hole, and having a space in which the plating layer does not exist;
an organic layer positioned on the first surface so as to fill a space inside the through electrode;
a second organic layer located on the organic layer;
a signal layer located on the second organic layer and connected to the through electrode through the second organic layer and the organic layer;
a plurality of the second organic layer positioned adjacent to the signal layer with a space therebetween and protruding in a planar direction along the first surface over at least a portion of an end portion not facing the signal layer; and a ground layer having a convex portion of a conductive substrate. a substrate having a first side and a second side opposite the first side;
an organic layer positioned on the substrate so as to partially contact the first surface;
a signal layer located on the organic layer;
A plurality of electrodes located between the substrate and the organic layer so as to be in contact with the first surface and protruding in a plane direction along the first surface over at least a part of an end not facing the signal layer a first ground layer having protrusions, wherein the organic layer is in contact with the first surface through gaps between the plurality of protrusions;
a second organic layer positioned on the signal layer so as to partially contact the organic layer;
a second ground layer located on the second organic layer and having a plurality of protrusions protruding in a planar direction along the first surface over at least a partial range of an end portion not facing the signal layer; A conductive substrate. 2. The conductive substrate of claim 1, further comprising a second ground layer overlying said second organic layer. 3. The conductive substrate of claim 2, further comprising a second ground layer overlying said organic layer. 6. The conductive substrate of any one of claims 1, 2, 4 and 5, further comprising a third ground layer located on said first surface. 7. The conductive substrate according to any one of claims 1 to 6, wherein the plurality of protrusions are periodically positioned along the edge of the ground layer not facing the signal layer. 8. The conductive substrate according to any one of claims 1 to 7, wherein the edge of the ground layer not facing the signal layer is an outer edge of the ground layer.

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