WO2024111285A1 - Multilayer substrate and method for producing multilayer substrate - Google Patents

Abstract

According to the present invention, a protective layer (18a) covers at least a part of the front main surface of a multilayer body (12). One or more internal conductors (28a) are provided inside the multilayer body (12) so as to overlap with the edge of the protective layer (18a) when viewed in the negative direction of the Z-axis and to extend along the edge. The front main surface of the multilayer body (12) is provided with a projection (P1). When viewed in the negative direction of the Z-axis, the projection (P1) has a linear shape that overlaps with the edge of the protective layer (18a) and the one or more internal conductors (28a), while extending along the edge of the protective layer (18a). The thickness of the protective layer (18a) in a portion where the protective layer (18a) overlaps with the projection (P1) when viewed in the negative direction of the Z-axis is smaller than the thickness of the protective layer (18a) in a portion where the protective layer (18a) does not overlap with the projection (P1) when viewed in the negative direction of the Z-axis. When viewed in the negative direction of the Z-axis, the length of the linear shaped projection (P1) is longer than the width of the linear shaped projection (P1).

Description

Multilayer board and method for manufacturing the same

The present invention relates to a multilayer substrate having a structure in which multiple insulating layers are stacked.

A known example of a conventional invention related to a multilayer board is the method of manufacturing a printed wiring board described in Patent Document 1. The purpose of this method of manufacturing a printed wiring board is to reduce the amount of undercut in the resist layer. The undercut in the resist layer is explained below.

The resist layer is formed by the following procedure: Photosensitive resist is applied to the substrate. The photosensitive resist is hardened by irradiating it with light through a mask. Finally, the unhardened photosensitive resist is removed. Here, near the edge of the mask, a portion in the shadow of the mask is generated during exposure. In this portion in the shadow of the mask, the photosensitive resist is not irradiated with sufficient light. Therefore, the photosensitive resist does not harden sufficiently in the portion in the shadow of the mask. As a result, as shown in FIG. 1(b) of Patent Document 1, the end face of the resist layer is inclined obliquely in the vertical direction. The phenomenon in which the end face of the resist layer is inclined obliquely in the vertical direction is called undercut. When such undercut occurs, the resist layer is easily peeled off from the substrate.

In light of this, an invention has been proposed that reduces the amount of undercut in the resist layer, as in the method of manufacturing a printed wiring board described in Patent Document 1. As a result, the method of manufacturing a printed wiring board described in Patent Document 1 suppresses peeling of the resist layer.

JP 2009-267173 A (see FIG. 1(b))

As described above, there is a demand for multilayer substrates that can prevent peeling of the resist layer.

The object of the present invention is to provide a new multilayer board and a method for manufacturing a multilayer board that can prevent peeling of the protective layer.

A multilayer substrate according to one embodiment of the present invention includes a laminate, a protective layer, and one or more internal conductors.
The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis,
The laminate has a positive principal surface and a negative principal surface located on the negative side of the Z axis from the positive principal surface,
the protective layer covers at least a portion of the positive main surface;
a material of the protective layer is different from a material of the plurality of insulator layers;
the one or more internal conductors are provided inside the multilayer substrate, overlap an edge of the protective layer when viewed in the negative direction of the Z axis, and extend along the edge of the protective layer when viewed in the negative direction of the Z axis;
A protrusion is provided on the front main surface of the laminate,
When viewed in the negative direction of the Z axis, the protrusion overlaps an edge of the protective layer and the one or more internal conductors, and has a linear shape extending along the edge of the protective layer;
a thickness of the protective layer at a portion where the protective layer overlaps with the protrusion as viewed in the negative direction of the Z axis is smaller than a thickness of the protective layer at a portion where the protective layer does not overlap with the protrusion as viewed in the negative direction of the Z axis,
When viewed in the negative direction of the Z axis, the length of the linear protrusion is greater than the width of the linear protrusion.

A multilayer substrate according to one embodiment of the present invention includes a laminate, a protective layer, and a plurality of internal conductors.
The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis,
The laminate has a positive principal surface and a negative principal surface located on the negative side of the Z axis from the positive principal surface,
the protective layer covers a portion of the positive principal surface,
a material of the protective layer is different from a material of the plurality of insulator layers;
the plurality of internal conductors are provided inside the multilayer substrate, overlap an edge of the protective layer when viewed in the negative direction of the Z axis, and are arranged along the edge of the protective layer when viewed in the negative direction of the Z axis;
A protrusion is provided on the front main surface of the laminate,
When viewed in the negative direction of the Z axis, the protrusion overlaps an edge of the protective layer and the plurality of internal conductors, and has a linear shape extending along the edge of the protective layer;
The thickness of the protective layer at a portion where the protective layer overlaps with the protrusion when viewed in the negative direction of the Z axis is smaller than the thickness of the protective layer at a portion where the protective layer does not overlap with the protrusion when viewed in the negative direction of the Z axis.

A method for manufacturing a multilayer substrate according to one embodiment of the present invention includes the steps of:
a bonding step of bonding the laminate;
a protective layer forming step of forming a protective layer on the laminated body;
Equipped with
The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis,
The laminate has a positive principal surface and a negative principal surface located on the negative side of the Z axis from the positive principal surface,
the protective layer covers at least a portion of the positive main surface;
a material of the protective layer is different from a material of the plurality of insulator layers;
one or more internal conductors are provided within the multilayer substrate;
In the compression bonding step, a protrusion is formed on the main surface of the laminate at a portion overlapping the one or more internal conductors,
In the protective layer forming step, the protective layer is formed on the positive main surface such that an edge of the protective layer overlaps the protrusion when viewed in the negative direction of the Z axis.

A method for manufacturing a multilayer substrate according to one embodiment of the present invention includes the steps of:
a bonding step of bonding the laminate;
a protective layer forming step of forming a protective layer on the laminated body;
a cutting step of cutting the laminate on which the protective layer is formed;
Equipped with
The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis,
The laminate has a positive principal surface and a negative principal surface located on the negative side of the Z axis from the positive principal surface,
the protective layer covers at least a portion of the positive main surface;
a material of the protective layer is different from a material of the plurality of insulator layers;
one or more internal conductors are provided within the laminate;
In the compression bonding step, a protrusion is formed on the main surface of the laminate at a portion overlapping the one or more internal conductors,
In the protective layer forming step, the protective layer is formed on the positive main surface such that the protective layer covers the protrusion when viewed in the negative direction of the Z axis,
In the cutting step, the laminate is cut so that the protrusion is divided when viewed in the negative direction of the Z axis.

The multilayer board and the method for manufacturing the multilayer board according to the present invention can prevent the protective layer from peeling off.

FIG. 1 is an exploded perspective view of a multilayer substrate 10. FIG. FIG. 2 is a cross-sectional view and a top view of the multilayer substrate 10. FIG. FIG. 3 is a front view of the multilayer board 10 when in use. FIG. 4 is a cross-sectional view of the multilayer substrate 10 during its manufacture. FIG. 5 is a cross-sectional view of the multilayer substrate 10 during its manufacture. FIG. 6 is a cross-sectional view and a top view of the multi-layer substrate 10a. FIG. 7 is a cross-sectional view of the multilayer substrate 10b. FIG. 8 is a cross-sectional view of the multilayer substrate 10c. FIG. 9 is a cross-sectional view and a top view of the multi-layer substrate 10d. FIG. 10 is a cross-sectional view and a top view of the multi-layer substrate 10e. FIG. 11 is a cross-sectional view and a top view of the multi-layer substrate 10f. FIG. 12 is a rear view of the multilayer board 10f during use. FIG. 13 is a cross-sectional view of the multilayer substrate 10 during its manufacture. FIG. 14 is a cross-sectional view of the multilayer substrate 10 during its manufacture. FIG. 15 is a cross-sectional view of the multilayer substrate 10 during its manufacture. FIG. 16 is a top view of the motherboard 100.

(Embodiment)
[Multilayer board structure]
The structure of a multilayer substrate 10 according to an embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is an exploded perspective view of the multilayer substrate 10. Fig. 2 is a cross-sectional view and a top view of the multilayer substrate 10. Fig. 2 shows a cross-section taken along line A-A in Fig. 1. Fig. 3 is a front view of the multilayer substrate 10 when in use. Note that in Fig. 1, reference symbols are given only to representative interlayer connection conductors v3, v4 among the multiple interlayer connection conductors v3, v4.

In this specification, directions are defined as follows. The stacking direction of the laminate 12 of the multilayer substrate 10 is defined as the up-down direction. The up-down direction coincides with the Z-axis direction. The up-down direction is the positive direction of the Z-axis. The down-down direction is the negative direction of the Z-axis. The direction in which the signal conductor layer 20 of the multilayer substrate 10 extends is defined as the left-right direction. The line width direction of the signal conductor layer 20 when viewed in the up-down direction is defined as the front-rear direction. The up-down direction, front-rear direction, and left-right direction are perpendicular to each other. Note that the up-down direction and the down-down direction may be interchanged, the left-right direction and the right-left direction may be interchanged, and the front-rear direction and the back-rear direction may be interchanged.

In the following, X is a part or member of the multilayer substrate 10. In this specification, unless otherwise specified, each part of X is defined as follows. The front part of X means the front half of X. The rear part of X means the rear half of X. The left part of X means the left half of X. The right part of X means the right half of X. The upper part of X means the upper half of X. The lower part of X means the lower half of X. The front end of X means the front end of X. The rear end of X means the rear end of X. The left end of X means the left end of X. The right end of X means the right end of X. The upper end of X means the upper end of X. The lower end of X means the lower end of X. The front end of X means the front end of X and its vicinity. The rear end of X means the rear end of X and its vicinity. The left end of X means the left end of X and its vicinity. The right end of X means the right end of X and its vicinity. The upper end of X means the upper end of X and its vicinity. The lower end of X means the lower end of X and its vicinity.

First, the structure of the multilayer board 10 will be described with reference to FIG. 1. The multilayer board 10 transmits high-frequency signals. The multilayer board 10 is used to electrically connect two circuits in electronic devices such as smartphones. As shown in FIG. 1, the multilayer board 10 includes a laminate 12, protective layers 18a and 18b, a signal conductor layer 20, a first ground conductor layer 22, a second ground conductor layer 24, mounting electrodes 26a and 26b, internal conductors 28a, 28b, 30a, 30b, 32a, and 32b, interlayer connection conductors v1 and v2, and a plurality of interlayer connection conductors v3 and v4.

The laminate 12 has a plate shape. Therefore, the laminate 12 has an upper main surface (positive main surface) and a lower main surface (negative main surface) located below the upper main surface (positive main surface) (negative side of the Z axis). The upper and lower main surfaces of the laminate 12 have a rectangular shape with long sides extending along the left-right axis. Therefore, the left-right length of the laminate 12 is longer than the front-rear length of the laminate 12. The laminate 12 is flexible.

As shown in FIG. 1, the laminate 12 has a structure in which the insulating layers 16a to 16d are stacked along the vertical axis (Z-axis). The insulating layers 16a to 16d are arranged in this order from top to bottom. The material of the insulating layers 16a to 16d is, for example, a thermoplastic resin. The thermoplastic resin is, for example, a liquid crystal polymer. The insulating layers 16a to 16d are fused together with adjacent layers vertically.

A high-frequency signal is transmitted to the signal conductor layer 20. As shown in FIG. 1, the signal conductor layer 20 is located on the upper main surface of the insulator layer 16c. The signal conductor layer 20 has a linear shape that extends along the left-right axis.

The first ground conductor layer 22 is provided in the laminate 12 as shown in FIG. 1. The first ground conductor layer 22 is located above the signal conductor layer 20 and overlaps with the signal conductor layer 20 when viewed in a downward direction. In this embodiment, the first ground conductor layer 22 is located on the upper main surface of the insulator layer 16a. The first ground conductor layer 22 also covers substantially the entire upper main surface of the insulator layer 16a. A ground potential is connected to the first ground conductor layer 22.

The second ground conductor layer 24 is provided in the laminate 12 as shown in FIG. 1. The second ground conductor layer 24 is located below the signal conductor layer 20 and overlaps with the signal conductor layer 20 when viewed in the downward direction. In this embodiment, the second ground conductor layer 24 is located on the lower main surface of the insulator layer 16d. The second ground conductor layer 24 also covers substantially the entire lower main surface of the insulator layer 16d. A ground potential is connected to the second ground conductor layer 24. The signal conductor layer 20, the first ground conductor layer 22, and the second ground conductor layer 24 as described above have a stripline structure.

As shown in FIG. 1, the mounting electrode 26a is located on the upper main surface (front main surface) of the laminate 12. More specifically, the mounting electrode 26a is located at the left end of the upper main surface of the insulator layer 16a. When viewed in the vertical direction, the mounting electrode 26a overlaps with the left end of the signal conductor layer 20. When viewed in the vertical direction, the mounting electrode 26a has a rectangular shape. The mounting electrode 26a is an external terminal through which high-frequency signals are input and output. The mounting electrode 26a is not in contact with the first ground conductor layer 22. The structure of the mounting electrode 26b is symmetrical to the structure of the mounting electrode 26a, so a description of it will be omitted.

As shown in Figures 1 and 2, the interlayer connection conductor v1 electrically connects the mounting electrode 26a and the left end of the signal conductor layer 20. The interlayer connection conductor v1 penetrates the insulator layers 16a and 16b in the vertical direction. The upper end of the interlayer connection conductor v1 contacts the mounting electrode 26a. The lower end of the interlayer connection conductor v1 contacts the left end of the signal conductor layer 20. The structure of the mounting electrode 26b and the interlayer connection conductor v2 is symmetrical to the structure of the mounting electrode 26a and the interlayer connection conductor v1, so a description thereof will be omitted.

The multiple interlayer connection conductors v3 electrically connect the first ground conductor layer 22 and the second ground conductor layer 24. More specifically, the multiple interlayer connection conductors v3 are located in front of the signal conductor layer 20 as shown in FIG. 1. The multiple interlayer connection conductors v3 are aligned in a row in the left-right direction. The multiple interlayer connection conductors v3 penetrate the insulator layers 16a to 16d in the up-down direction. The upper ends of the multiple interlayer connection conductors v3 are in contact with the first ground conductor layer 22. The lower ends of the multiple interlayer connection conductors v3 are in contact with the second ground conductor layer 24.

The multiple interlayer connection conductors v4 electrically connect the first ground conductor layer 22 and the second ground conductor layer 24. More specifically, the multiple interlayer connection conductors v4 are located behind the signal conductor layer 20 as shown in FIG. 1. The multiple interlayer connection conductors v4 are aligned in a row in the left-right direction. The multiple interlayer connection conductors v4 penetrate the insulator layers 16a to 16d in the up-down direction. The upper ends of the multiple interlayer connection conductors v4 are in contact with the first ground conductor layer 22. The lower ends of the multiple interlayer connection conductors v4 are in contact with the second ground conductor layer 24.

The signal conductor layer 20, the first ground conductor layer 22, the second ground conductor layer 24, the interlayer connection conductors v1, v2, the multiple interlayer connection conductors v3, and the multiple interlayer connection conductors v4 as described above are one or more circuit conductors that form an electric circuit.

The protective layer 18a covers a portion of the upper main surface (positive main surface in the Z-axis direction) of the laminate 12. As a result, the protective layer 18a protects the first ground conductor layer 22. However, the protective layer 18a has rectangular openings h1 to h6. Therefore, the protective layer 18a has six ring-shaped edges E when viewed downward (negative direction of the Z-axis). The opening h1 overlaps with the mounting electrode 26a when viewed in the up-down direction. That is, the mounting electrode 26a is located in an area surrounded by the ring-shaped edges E when viewed downward (negative direction of the Z-axis). As a result, the mounting electrode 26a is exposed to the outside from the multilayer substrate 10. The opening h2 is located in front of the opening h1. A portion of the first ground conductor layer 22 is exposed to the outside from the multilayer substrate 10 through the opening h2. The opening h3 is located behind the opening h1. A portion of the first ground conductor layer 22 is exposed to the outside from the multilayer substrate 10 through the opening h3. As a result, a portion of the first ground conductor layer 22 functions as a ground terminal. Note that the structure of the openings h4 to h6 is symmetrical to the structure of the openings h1 to h3, so a description of it will be omitted.

The protective layer 18b covers the lower main surface of the laminate 12. In this way, the protective layer 18b protects the second ground conductor layer 24.

The material of the protective layers 18a and 18b is different from the material of the insulating layers 16a to 16d. The protective layers 18a and 18b are what is known as solder resist. The material of the solder resist is a composition containing an alkali-soluble resin, a photopolymerization initiator, an epoxy resin to improve heat resistance, and inorganic powder.

The internal conductors 28a, 30a, and 32a are provided inside the laminate 12. In this embodiment, the internal conductors 28a, 30a, and 32a are located at the left end of the upper main surface of the insulator layer 16b. As shown in FIG. 2, each of the internal conductors 28a, 30a, and 32a overlaps with the edge E of the protective layer 18a when viewed downward (negative direction of the Z axis). Furthermore, each of the internal conductors 28a, 30a, and 32a extends along the edge E of the protective layer 18a when viewed downward (negative direction of the Z axis). In this embodiment, each of the internal conductors 28a, 30a, and 32a has a ring shape that follows the ring-shaped edge E of the openings h1, h2, and h3 of the protective layer 18a when viewed downward (negative direction of the Z axis). Therefore, the internal conductors 28a, 30a, and 32a have a rectangular ring shape when viewed downward. The structure of the internal conductors 28b, 30b, and 32b is symmetrical to the structure of the internal conductors 28a, 30a, and 32a, so a description thereof will be omitted. The internal conductors 28a, 28b, 30a, 30b, 32a, and 32b described above are not electrically connected in series with one or more circuit conductors. Therefore, the internal conductors 28a, 28b, 30a, 30b, 32a, and 32b do not transmit high-frequency signals, are not connected to a ground potential, or are not connected to a power supply potential. The potential of the internal conductors 28a, 28b, 30a, 30b, 32a, and 32b is a floating potential.

The signal conductor layer 20, the first ground conductor layer 22, the second ground conductor layer 24, the mounting electrodes 26a, 26b, and the internal conductors 28a, 28b, 30a, 30b, 32a, and 32b described above are formed, for example, by etching metal foil provided on the upper or lower main surfaces of the insulator layers 16a to 16d. The metal foil is, for example, copper foil. In this way, the signal conductor layer 20, the first ground conductor layer 22, the second ground conductor layer 24, the mounting electrodes 26a, 26b (at least one or more circuit conductors), and the internal conductors 28a, 28b, 30a, 30b, 32a, and 32b are metal foils provided on the main surfaces of the insulator layers 16a to 16d.

The interlayer connection conductors v1 to v4 are, for example, via hole conductors. The via hole conductors are produced by forming through holes in the insulator layers 16a to 16d, filling the through holes with conductive paste, and sintering the conductive paste. The material of the interlayer connection conductors v1 to v4 is a mixture of resin and metal.

As shown in FIG. 2, the upper main surface (positive main surface) of the laminate 12 has protrusions P1 to P6 (only protrusion P1 is shown in FIG. 2). Protrusions P1 to P3 are located at the left end of the upper main surface of the insulator layer 16a. Protrusions P4 to P6 are located at the right end of the upper main surface of the insulator layer 16a. When viewed downward (negative direction of the Z axis), each of the protrusions P1 to P6 overlaps with the edge E of the openings h1 to h6 in the protective layer 18a and the internal conductors 28a, 28b, 30a, 30b, 32a, and 32b.

Furthermore, each of the protrusions P1 to P6 has a linear shape extending along the internal conductors 28a, 28b, 30a, 30b, 32a, 32b and the edge E of the openings h1 to h6 of the protective layer 18a. Therefore, each of the protrusions P1 to P6 has a ring shape that follows the ring-shaped edge E of the internal conductors 28a, 28b, 30a, 30b, 32a, 32b and the openings h1 to h6 when viewed downward (negative direction of the Z axis). As a result, when viewed downward (negative direction of the Z axis), the length of each of the linear protrusions P1 to P6 is longer than the width of the linear protrusions P1 to P6. Because the protrusions P1 to P6 are provided as described above, the thickness T1 of the protective layer 18a at the portions where the protective layer 18a overlaps with the protrusions P1 to P6 when viewed downward (negative direction of the Z axis) is smaller than the thickness T2 of the protective layer 18a at the portions where the protective layer 18a does not overlap with the protrusions P1 to P6 when viewed downward (negative direction of the Z axis).

The multilayer substrate 10 described above has flexibility. Therefore, as shown in FIG. 3, the multilayer substrate 10 can be bent. Specifically, the multilayer substrate 10 has a first section A1 and a second section A2. The protrusions P1 to P3 are located in the second section A2. The second section A2 is bent when viewed in the forward direction (the positive direction of the Y-axis perpendicular to the Z-axis).

[Method of manufacturing multilayer substrate 10]
Next, a method for manufacturing the multilayer substrate 10 will be described with reference to the drawings. Figures 4 and 5 are cross-sectional views of the multilayer substrate 10 during manufacturing.

First, prepare the insulator layers 16a to 16d with metal foil attached to the upper or lower principal surface. Then, pattern the metal foil to form the signal conductor layer 20, the first ground conductor layer 22, the second ground conductor layer 24, the mounting electrodes 26a, 26b, and the internal conductors 28a, 28b, 30a, 30b, 32a, and 32b.

Next, as shown in FIG. 4, the insulator layers 16a to 16d are arranged from top to bottom in this order. As a result, the internal conductors 28a, 28b, 30a, 30b, 32a, and 32b are provided inside the laminate 12. Then, the laminate in which the insulator layers 16a to 16d are stacked is compressed (compression bonding process). In the compression bonding process, an isotropic press is used. In addition, in the thermocompression bonding process, a heat treatment is also performed. As shown in FIG. 5, the insulator layer 16a is pushed upward by the internal conductors 28a, 28b, 30a, 30b, 32a, and 32b. As a result, in the compression bonding process, protrusions P1 to P6 are formed on the upper main surface (front main surface) of the laminate 12 in the portions that overlap with the internal conductors 28a, 28b, 30a, 30b, 32a, and 32b.

2, protective layers 18a and 18b are formed on the laminate 12 that has been pressed (protective layer forming process). In the protective layer forming process, the protective layer 18a is formed on the upper main surface (positive main surface) of the laminate 12 so that the edge E of the protective layer 18a overlaps the protrusions P1 to P6 when viewed downward (negative direction of the Z axis). Specifically, the photosensitive material of the protective layers 18a and 18b is applied to the entire upper main surface and the entire lower main surface of the laminate 12 by screen printing. At this time, the thickness T1 of the material of the protective layer 18a at the portion where the protective layer 18a overlaps the protrusions P1 to P6 when viewed downward (negative direction of the Z axis) is smaller than the thickness T2 of the material of the protective layer 18a at the portion where the protective layer 18a does not overlap the protrusions P1 to P6 when viewed downward (negative direction of the Z axis). After this, the material of the protective layers 18a and 18b is exposed to light. Finally, the uncured material of the protective layers 18a and 18b is removed. This forms the protective layer 18a with a shape in which the edge E of the protective layer 18a overlaps with the protrusions P1 to P6. Through the above steps, the multilayer substrate 10 is completed.

[effect]
According to the multilayer board 10, peeling of the protective layer 18a can be suppressed. More specifically, the internal conductor 28a is provided inside the laminate 12, and overlaps the edge E of the protective layer 18a when viewed in the downward direction, and extends along the edge E of the protective layer 18a when viewed in the downward direction. As a result, a protrusion P1 that overlaps with the internal conductor 28a when viewed in the downward direction is formed. Then, the protective layer 18a is formed on the upper main surface of the laminate 12 having such a protrusion P1. As a result, the thickness T1 of the protective layer 18a at the portion where the protective layer 18a overlaps with the protrusion P1 when viewed in the downward direction is smaller than the thickness T2 of the protective layer 18a at the portion where the protective layer 18a does not overlap with the protrusion P1 when viewed in the downward direction. In the multilayer board 10 as described above, the thickness in the vertical direction of the edge E of the protective layer 18a is small. Therefore, the amount of undercut occurring in the protective layer 18a is reduced. Therefore, according to the multilayer board 10, peeling of the protective layer 18a can be suppressed.

The multilayer substrate 10 can prevent peeling of the protective layer 18a without adding a new process. More specifically, in the multilayer substrate 10, the internal conductor 28a is formed in order to form the protrusion P1. At least a portion of the one or more circuit conductors and the internal conductor 28a are metal foils provided on the main surfaces of the insulator layers 16a to 16d. In other words, the process of forming the internal conductor 28a can be carried out in the same manner as the process of forming at least a portion of the one or more circuit conductors. Therefore, it is not necessary to add a new process to form the internal conductor 28a.

Since the second section A2 is bent, peeling of the protective layer 18a is likely to occur in the second section A2. Therefore, the protrusion P1 is located in the second section A2. This effectively prevents peeling of the protective layer 18a.

The multilayer substrate 10 makes it easy for the protrusion P1 to be formed. More specifically, the mounting electrode 26a is located in an area surrounded by the edge E of the ring shape of the opening h1 when viewed from below. The internal conductor 28a has a ring shape that follows the edge E of the ring shape of the opening h1 when viewed from below. As a result, in the crimping process of the laminate 12, the hard mounting electrode 26a is pressed downward, and the mounting electrode 26a and its surroundings are recessed downward. Meanwhile, the portion of the upper main surface of the laminate 12 where the internal conductor 28a is present is pressed upward by the internal conductor 28a. As a result, the protrusion P1 is easy to be formed.

(First Modification)
A multilayer substrate 10a according to a first modified example will be described below with reference to the drawings. Fig. 6 is a cross-sectional view and a top view of the multilayer substrate 10a.

The multilayer substrate 10a differs from the multilayer substrate 10 in that it further includes an internal conductor 34a and a plurality of first connecting conductors v10.

The multilayer substrate 10a further includes an internal conductor 34a. Therefore, the number of internal conductors is multiple. In addition, when viewed in the downward direction (negative direction of the Z axis), the internal conductors 28a and 34a overlap each other. When viewed in the downward direction, the internal conductor 34a has the same shape as the internal conductor 28a. The internal conductor 34a is located on the upper main surface of the insulator layer 16c. The multilayer substrate 10a further includes a plurality of first connecting conductors v10. The plurality of first connecting conductors v10 penetrate the insulator layer 16b (any of the plurality of insulator layers 16a to 16d) along the vertical axis (Z axis), and connect the internal conductor 28a and the internal conductor 34a (two of the plurality of internal conductors). When viewed in the downward direction, the plurality of first connecting conductors v10 are arranged at equal intervals along the internal conductors 28a and 34a. The other structure of the multilayer substrate 10a is the same as that of the multilayer substrate 10, so a description thereof will be omitted. Multilayer board 10a can achieve the same effects as multilayer board 10.

In the multilayer substrate 10a, the internal conductor 34a and the multiple first connecting conductors v10 are located below the internal conductor 28a. This makes it easier to form the protrusion P1.

(Second Modification)
A multilayer substrate 10b according to a second modified example will now be described with reference to the drawings. Fig. 7 is a cross-sectional view of the multilayer substrate 10b.

The multilayer board 10b differs from the multilayer board 10 in the following respects: The edge E of the protective layer 18a is a straight line extending along the front-rear axis. The multilayer board 10b further includes internal conductors 34a, 36a, 38a, a surface conductor 40a, a first connecting conductor v10, a second connecting conductor v12, a third connecting conductor v14, and a fourth connecting conductor v16.

The internal conductors 34a, 36a, 38a are located on the upper main surfaces of the insulator layers 16c to 16e. When viewed from below, the internal conductors 34a, 36a, 38a overlap the edge E of the protective layer 18a. Therefore, when viewed from below, the internal conductors 34a, 36a, 38a extend along the front-to-rear axis. When viewed from below, the internal conductors 34a, 36a, 38a overlap each other.

The surface conductor 40a is located on the upper main surface (positive main surface) of the laminate 12, and overlaps with the edge E of the protective layer 18a when viewed downward (negative direction of the Z axis). Therefore, the surface conductor 40a extends along the front-to-rear axis when viewed downward. The surface conductor 40a overlaps with the internal conductors 34a, 36a, and 38a when viewed downward.

The multiple first connecting conductors v10 penetrate the insulator layer 16b (any of the multiple insulator layers 16a to 16d) along the vertical axis (Z-axis) and connect the internal conductor 28a and the internal conductor 34a (two of the multiple internal conductors). When viewed in the downward direction, the multiple first connecting conductors v10 are aligned along the internal conductors 28a, 34a, 36a, 38a and the surface conductor 40a.

The second connecting conductors v12 penetrate the insulator layer 16c (any of the insulator layers 16a to 16d) along the vertical axis (Z axis), and connect the internal conductor 34a and the internal conductor 36a (two of the internal conductors). The second connecting conductors v12 are located below the first connecting conductors v10 (negative side of the Z axis), and overlap with the first connecting conductors v10 when viewed in the downward direction (negative direction of the Z axis). The second connecting conductors v12 are aligned along the internal conductors 28a, 34a, 36a, 38a and the surface conductor 40a when viewed in the downward direction.

The multiple third connecting conductors v14 penetrate the insulator layer 16d (any of the multiple insulator layers 16a to 16d) along the up-down axis (Z-axis), and connect the internal conductor 36a and the internal conductor 38a (two of the multiple internal conductors). The multiple third connecting conductors v14 are located below the multiple first connecting conductors v10 (negative side of the Z-axis), and overlap with the multiple first connecting conductors v10 when viewed in the downward direction (negative direction of the Z-axis). The multiple third connecting conductors v14 are lined up along the internal conductors 28a, 34a, 36a, 38a and the surface conductor 40a when viewed in the downward direction.

The multiple fourth connecting conductors v16 penetrate the insulator layer 16a (any of the multiple insulator layers 16a to 16d) along the vertical axis (Z axis) and connect the surface conductor 40a and the internal conductor 28a. The multiple fourth connecting conductors v16 overlap with the multiple first connecting conductors v10 when viewed in the downward direction (negative direction of the Z axis). The multiple fourth connecting conductors v16 are aligned along the internal conductors 28a, 34a, 36a, 38a and the surface conductor 40a when viewed in the downward direction. The rest of the structure of the multilayer board 10b is the same as that of the multilayer board 10, so a description will be omitted. The multilayer board 10b can achieve the same effects as the multilayer board 10.

In the multilayer substrate 10b, in addition to the internal conductor 28a, internal conductors 34a, 36a, 38a, a surface conductor 40a, a plurality of first connecting conductors v10, a plurality of second connecting conductors v12, a plurality of third connecting conductors v14, and a plurality of fourth connecting conductors v16 are provided. This makes it easier to form the protrusion P1.

(Third Modification)
A multilayer substrate 10c according to a third modified example will now be described with reference to the drawings. Fig. 8 is a cross-sectional view of the multilayer substrate 10c.

Multilayer board 10c differs from multilayer board 10 in that an undercut occurs at edge E of opening h1 in protective layer 18a. However, thickness T1 of protective layer 18a at the portion where protective layer 18a overlaps with protrusion P1 when viewed from below is smaller than thickness T2 of protective layer 18a at the portion where protective layer 18a does not overlap with protrusion P1 when viewed from below. Therefore, the amount of undercut at edge E of opening h1 in protective layer 18a is smaller in multilayer board 10b. The rest of the structure of multilayer board 10c is the same as multilayer board 10, so a description will be omitted. Multilayer board 10c can achieve the same effects as multilayer board 10.

(Fourth Modification)
A multi-layer substrate 10d according to a fourth modified example will be described below with reference to the drawings. Fig. 9 shows a cross-sectional view and a top view of the multi-layer substrate 10d.

The multilayer board 10d differs from the multilayer board 10b in that it has multiple internal conductors 28a instead of the internal conductor 28a, and does not have the internal conductors 34a, 36a, 38a, the surface conductor 40a, the first connecting conductor v10, the second connecting conductor v12, the third connecting conductor v14, and the fourth connecting conductor v16. The multiple internal conductors 28a are provided inside the laminate 12. The multiple internal conductors 28a overlap the edge E of the protective layer 18b when viewed downward (negative direction of the Z axis), and are arranged at equal intervals along the edge E of the protective layer 18a when viewed downward (negative direction of the Z axis). The multiple first connecting conductors v10 are not in contact with each other. The other structure of the multilayer board 10d is the same as that of the multilayer board 10, so a description will be omitted. The multilayer board 10d can achieve the same effect as the multilayer board 10. This makes it difficult for the protective layer 18a to peel off at the edge E where it overlaps with the multiple internal conductors 28a.

(Fifth Modification)
A multilayer substrate 10e according to a fifth modified example will be described below with reference to the drawings. Fig. 10 is a cross-sectional view and a top view of the multilayer substrate 10e.

The multilayer board 10e differs from the multilayer board 10d in that it has a plurality of first connecting conductors v10 instead of a plurality of internal conductors 28a. The plurality of first connecting conductors v10 are a plurality of internal conductors. The plurality of first connecting conductors v10 penetrate the insulator layer 16b along the up-down axis. The plurality of first connecting conductors v10 overlap with the edge E of the protective layer 18b when viewed downward (negative direction of the Z axis), and are arranged at equal intervals along the edge E of the protective layer 18a when viewed downward (negative direction of the Z axis). The plurality of first connecting conductors v10 are not in contact with adjacent ones. The other structure of the multilayer board 10e is the same as that of the multilayer board 10d, so a description thereof will be omitted. The multilayer board 10e can achieve the same effect as the multilayer board 10d.

(Sixth Modification)
A multilayer substrate 10f according to a sixth modified example will be described below with reference to the drawings. Fig. 11 is a cross-sectional view of the multilayer substrate 10f and a top view of the multilayer substrate 10f. Fig. 12 is a rear view of the multilayer substrate 10f when in use.

Multilayer board 10f differs from multilayer board 10d in that laminate 12 is cut at protrusion P1 and that internal conductor 28a has a linear shape when viewed downward. Such multilayer board 10f can be bent as shown in FIG. 12. Specifically, multilayer board 10 has first section A1 and second section A2. Protrusion P1 is located in second section A2. Second section A2 is bent when viewed in the forward direction (positive direction of Y-axis perpendicular to Z-axis). Other structure of multilayer board 10f is the same as multilayer board 10d, so description will be omitted.

Next, the manufacturing method of the multilayer substrate 10f will be described with reference to the drawings. Figures 13, 14, and 15 are cross-sectional views of the multilayer substrate 10 during manufacturing. Figure 16 is a top view of the mother substrate 100.

First, prepare the insulator layers 16a to 16e with metal foil attached to the upper or lower principal surface. Then, pattern the metal foil to form the signal conductor layer 20, the first ground conductor layer 22, the second ground conductor layer 24, the mounting electrodes 26a and 26b, and the internal conductor 28a.

Next, as shown in FIG. 13, the insulator layers 16a to 16e are arranged from top to bottom in this order. Then, the laminate in which the insulator layers 16a to 16e are stacked is compressed (compression bonding process). In the compression bonding process, an isotropic press is used. In addition, in the thermocompression bonding process, a heat treatment is also performed. At this time, as shown in FIG. 14, the insulator layer 16a is pushed upward by the internal conductor 28a. As a result, in the compression bonding process, protrusions P1 are formed on each of the portions of the upper main surface (front main surface) of the laminate 12 that overlap with the internal conductor 28a. In addition, the internal conductor 28a is provided inside the laminate 12.

Next, as shown in FIG. 15, protective layers 18a and 18b are formed on the laminate 12 that has been pressed (protective layer forming process). In the protective layer forming process, the protective layer 18a is formed on the upper main surface (positive main surface) of the laminate 12 so that the protective layer 18a covers the protrusion P1 when viewed downward (negative direction of the Z axis). Specifically, the material of the protective layers 18a and 18b is applied to the upper and lower main surfaces of the laminate 12 by screen printing. The thickness T1 of the protective layer 18a at the portion where the protective layer 18a overlaps with the protrusion P1 when viewed downward (negative direction of the Z axis) is smaller than the thickness T2 of the protective layer 18a at the portion where the protective layer 18a does not overlap with the protrusion P1 when viewed downward (negative direction of the Z axis).

Next, as shown in FIG. 11, the laminate 12 on which the protective layers 18a and 18b are formed is cut (cutting process). In the cutting process, the laminate 12 is cut so that the protrusion P1 is divided when viewed downward (negative direction of the Z axis). In the cutting process, the mother board 100 is cut along the internal conductor 28a as shown in FIG. 16. Through the above steps, the multilayer board 10f is completed.

Other Embodiments
The multilayer board according to the present invention is not limited to the multilayer boards 10, 10a to 10f, and may be modified within the scope of the invention. The structures of the multilayer boards 10, 10a to 10f may be combined in any desired manner.

Note that protective layer 18b is not a required component.

In addition, a protrusion may be provided on the lower main surface of the laminate 12, and the edge of the protective layer 18b may overlap the protrusion.

Note that the signal conductor layer 20, the first ground conductor layer 22, and the second ground conductor layer 24 are not essential components.

The material of the insulator layers 16a to 16e may be, for example, ceramic.

The protective layer 18a only needs to cover at least a portion of the upper main surface of the laminate 12. Therefore, the protective layer 18a may cover the entire upper main surface of the laminate 12. In this case, a protrusion P1 is present near the outer edge of the upper main surface of the laminate 12. This prevents the protective layer 18a from peeling off from the outer edge of the upper main surface of the laminate 12.

The potential of the internal conductors 28a, 34a, 36a, 38a and the surface conductor 40a does not have to be a floating potential. The internal conductors 28a, 34a, 36a, 38a and the surface conductor 40a may be connected to a ground potential, for example. However, if the potential of the internal conductors 28a, 34a, 36a, 38a and the surface conductor 40a is a floating potential, the internal conductors 28a, 34a, 36a, 38a and the surface conductor 40a are less likely to affect the surrounding electric circuits.

In addition, only one first connecting conductor v10 may be provided in the multilayer substrate 10e.

In addition, in the multilayer boards 10a and 10e, adjacent first connecting conductors v10 may be in contact with each other.

The present invention has the following structure:

(1)
The multilayer substrate includes a laminate, a protective layer, and one or more internal conductors,
The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis,
The laminate has a positive principal surface and a negative principal surface located on the negative side of the Z axis from the positive principal surface,
the protective layer covers at least a portion of the positive main surface;
a material of the protective layer is different from a material of the plurality of insulator layers;
the one or more internal conductors are provided inside the laminate, overlap an edge of the protective layer when viewed in the negative direction of the Z axis, and extend along the edge of the protective layer when viewed in the negative direction of the Z axis;
A protrusion is provided on the front main surface of the laminate,
When viewed in the negative direction of the Z axis, the protrusion overlaps an edge of the protective layer and the one or more internal conductors, and has a linear shape extending along the edge of the protective layer;
a thickness of the protective layer at a portion where the protective layer overlaps with the protrusion as viewed in the negative direction of the Z axis is smaller than a thickness of the protective layer at a portion where the protective layer does not overlap with the protrusion as viewed in the negative direction of the Z axis,
When viewed in the negative direction of the Z axis, the length of the linear protrusion is longer than the width of the linear protrusion.
Multilayer board.

(2)
The multilayer substrate further comprises one or more circuit conductors forming an electrical circuit;
the one or more inner conductors are not electrically connected in series with the one or more circuit conductors;
A multilayer substrate according to (1).

(3)
The multilayer substrate further comprises one or more circuit conductors forming an electrical circuit;
At least a portion of the one or more circuit conductors and the one or more internal conductors are metal foils provided on the main surfaces of the plurality of insulating layers.
A multilayer substrate according to (1) or (2).

(4)
The number of the one or more internal conductors is plural,
When viewed in the negative direction of the Z axis, the multiple internal conductors overlap each other.
A multilayer substrate according to any one of (1) to (3).

(5)
The multilayer substrate further includes a first connection conductor,
The first connection conductor passes through any one of the plurality of insulating layers along the Z-axis and connects two of the plurality of internal conductors.
A multilayer substrate according to (4).

(6)
The multilayer substrate further includes a second connection conductor,
the second connecting conductor penetrates any one of the plurality of insulating layers along the Z-axis, connects two of the plurality of internal conductors, is located on the negative side of the Z-axis relative to the first connecting conductor, and overlaps with the first connecting conductor when viewed in the negative direction of the Z-axis.
A multilayer substrate according to (5).

(7)
The one or more internal conductors are connecting conductors that pass through any one of the plurality of insulating layers along the Z-axis.
A multilayer substrate according to (1) or (2).

(8)
The multilayer substrate has a first section and a second section,
The protrusion is located in the second section,
The second section is bent when viewed in a positive direction of a Y axis perpendicular to the Z axis.
A multilayer substrate according to any one of (1) to (7).

(9)
The multilayer substrate further includes a surface conductor,
the surface conductor is located on the positive principal surface and overlaps an edge of the protective layer when viewed in the negative direction of the Z axis;
A multilayer substrate according to any one of (1) to (8).

(10)
The multilayer substrate further includes a mounting electrode,
the protective layer has a ring-shaped edge when viewed in the negative direction of the Z axis,
the mounting electrode is located on the positive principal surface and in a region surrounded by an edge of the ring shape when viewed in the negative direction of the Z axis,
the internal conductor has a ring shape along an edge of the ring shape when viewed in the negative direction of the Z axis,
The protrusion has a ring shape along an edge of the ring shape when viewed in the negative direction of the Z axis.
A multilayer substrate according to any one of (1) to (9).

(11)
The multilayer substrate includes a laminate, a protective layer, and a plurality of internal conductors.
The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis,
The laminate has a positive principal surface and a negative principal surface located on the negative side of the Z axis from the positive principal surface,
the protective layer covers a portion of the positive principal surface,
a material of the protective layer is different from a material of the plurality of insulator layers;
the plurality of internal conductors are provided inside the laminate, overlap an edge of the protective layer when viewed in the negative direction of the Z axis, and are arranged along the edge of the protective layer when viewed in the negative direction of the Z axis;
A protrusion is provided on the front main surface of the laminate,
When viewed in the negative direction of the Z axis, the protrusion overlaps an edge of the protective layer and the plurality of internal conductors, and has a linear shape extending along the edge of the protective layer;
a thickness of the protective layer at a portion where the protective layer overlaps with the protrusion when viewed in the negative direction of the Z axis is smaller than a thickness of the protective layer at a portion where the protective layer does not overlap with the protrusion when viewed in the negative direction of the Z axis;
Multilayer board.

(12)
The manufacturing method of the multilayer board is as follows:
a bonding step of bonding the laminate;
a protective layer forming step of forming a protective layer on the laminated body;
Equipped with
The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis,
The laminate has a positive principal surface and a negative principal surface located on the negative side of the Z axis from the positive principal surface,
the protective layer covers at least a portion of the positive main surface;
a material of the protective layer is different from a material of the plurality of insulator layers;
One or more internal conductors are provided within the laminate;
In the compression bonding step, a protrusion is formed on the main surface of the laminate at a portion overlapping the one or more internal conductors,
In the protective layer forming step, the protective layer is formed on the positive main surface such that an edge of the protective layer overlaps the protrusion when viewed in the negative direction of the Z axis.
A method for manufacturing a multilayer board.

(13)
the protective layer has a ring-shaped edge when viewed in the negative direction of the Z axis,
a mounting electrode is located on the positive principal surface and in a region surrounded by an edge of the ring shape when viewed in the negative direction of the Z axis;
The protrusion has a ring shape along an edge of the ring shape when viewed in the negative direction of the Z axis,
The internal conductor has a ring shape along an edge of the ring shape when viewed in the negative direction of the Z axis.
A method for manufacturing a multilayer substrate according to (12).

(14)
The manufacturing method of the multilayer board is as follows:
a bonding step of bonding the laminate;
a protective layer forming step of forming a protective layer on the laminated body;
a cutting step of cutting the laminate on which the protective layer is formed;
Equipped with
The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis,
The laminate has a positive principal surface and a negative principal surface located on the negative side of the Z axis from the positive principal surface,
the protective layer covers at least a portion of the positive main surface;
a material of the protective layer is different from a material of the plurality of insulator layers;
One or more internal conductors are provided within the laminate;
In the compression bonding step, a protrusion is formed on the main surface of the laminate at a portion overlapping the one or more internal conductors,
In the protective layer forming step, the protective layer is formed on the positive main surface such that the protective layer covers the protrusion when viewed in the negative direction of the Z axis,
In the cutting step, the laminate is cut so that the protrusion is divided when viewed in the negative direction of the Z axis.
A method for manufacturing a multilayer board.

Reference Signs 10, 10a to 10f: Multilayer board 12: Laminated bodies 16a to 16e: Insulator layers 18a, 18b: Protective layer 20: Signal conductor layer 22: First ground conductor layer 24: Second ground conductor layer 26a, 26b: Mounting electrodes 28a, 28b, 30a, 30b, 32a, 32b, 34a, 36a, 38a: Internal conductor 40a: Surface conductor A1: First section A2: Second section E: Edges P1 to P6: Protrusions h1 to h6: Opening v10: First connecting conductor v12: Second connecting conductor v14: Third connecting conductor v16: Fourth connecting conductor

Claims (15)

A laminate, a protective layer, and one or more internal conductors,
The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis,
The laminate has a positive principal surface and a negative principal surface located on the negative side of the Z axis from the positive principal surface,
the protective layer covers at least a portion of the positive main surface;
a material of the protective layer is different from a material of the plurality of insulator layers;
the one or more internal conductors are provided inside the laminate, overlap an edge of the protective layer when viewed in the negative direction of the Z axis, and extend along the edge of the protective layer when viewed in the negative direction of the Z axis;
A protrusion is provided on the front main surface of the laminate,
When viewed in the negative direction of the Z axis, the protrusion overlaps an edge of the protective layer and the one or more internal conductors, and has a linear shape extending along the edge of the protective layer;
a thickness of the protective layer at a portion where the protective layer overlaps with the protrusion as viewed in the negative direction of the Z axis is smaller than a thickness of the protective layer at a portion where the protective layer does not overlap with the protrusion as viewed in the negative direction of the Z axis,
When viewed in the negative direction of the Z axis, the length of the linear protrusion is longer than the width of the linear protrusion.
Multilayer board. one or more circuit conductors forming an electrical circuit;
the one or more inner conductors are not electrically connected in series with the one or more circuit conductors;
The multilayer substrate according to claim 1 . one or more circuit conductors forming an electrical circuit;
At least a portion of the one or more circuit conductors and the one or more internal conductors are metal foils provided on the main surfaces of the plurality of insulating layers.
The multilayer substrate according to claim 1 . At least a portion of the one or more circuit conductors and the one or more internal conductors are metal foils provided on the main surfaces of the plurality of insulating layers.
The multilayer substrate according to claim 2 . The number of the one or more internal conductors is plural,
When viewed in the negative direction of the Z axis, the multiple internal conductors overlap each other.
The multilayer substrate according to any one of claims 1 to 4. A first connecting conductor is provided,
The first connection conductor passes through any one of the plurality of insulating layers along the Z-axis and connects two of the plurality of internal conductors.
The multilayer substrate according to claim 4. A second connecting conductor is provided.
the second connecting conductor penetrates any one of the plurality of insulating layers along the Z-axis, connects two of the plurality of internal conductors, is located on the negative side of the Z-axis relative to the first connecting conductor, and overlaps with the first connecting conductor when viewed in the negative direction of the Z-axis.
The multilayer substrate according to claim 6. The one or more internal conductors are connecting conductors that pass through any one of the plurality of insulating layers along the Z-axis.
The multilayer substrate according to any one of claims 1 to 7. A first section and a second section,
The protrusion is located in the second section,
The second section is bent when viewed in a positive direction of a Y axis perpendicular to the Z axis.
The multilayer substrate according to any one of claims 1 to 8. A surface conductor is provided.
the surface conductor is located on the positive principal surface and overlaps an edge of the protective layer when viewed in the negative direction of the Z axis;
The multilayer substrate according to any one of claims 1 to 9. A mounting electrode is provided,
the protective layer has a ring-shaped edge when viewed in the negative direction of the Z axis,
the mounting electrode is located on the positive principal surface and in a region surrounded by an edge of the ring shape when viewed in the negative direction of the Z axis,
the internal conductor has a ring shape along an edge of the ring shape when viewed in the negative direction of the Z axis,
The protrusion has a ring shape along an edge of the ring shape when viewed in the negative direction of the Z axis.
The multilayer substrate according to any one of claims 1 to 10. The laminate includes a protective layer and a plurality of internal conductors.
The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis,
The laminate has a positive principal surface and a negative principal surface located on the negative side of the Z axis from the positive principal surface,
the protective layer covers a portion of the positive principal surface,
a material of the protective layer is different from a material of the plurality of insulator layers;
the plurality of internal conductors are provided inside the laminate, overlap an edge of the protective layer when viewed in the negative direction of the Z axis, and are arranged along the edge of the protective layer when viewed in the negative direction of the Z axis;
A protrusion is provided on the front main surface of the laminate,
When viewed in the negative direction of the Z axis, the protrusion overlaps an edge of the protective layer and the plurality of internal conductors, and has a linear shape extending along the edge of the protective layer;
a thickness of the protective layer at a portion where the protective layer overlaps with the protrusion when viewed in the negative direction of the Z axis is smaller than a thickness of the protective layer at a portion where the protective layer does not overlap with the protrusion when viewed in the negative direction of the Z axis;
Multilayer board. a bonding step of bonding the laminate;
a protective layer forming step of forming a protective layer on the laminated body;
Equipped with
The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis,
The laminate has a positive principal surface and a negative principal surface located on the negative side of the Z axis from the positive principal surface,
the protective layer covers at least a portion of the positive main surface;
a material of the protective layer is different from a material of the plurality of insulator layers;
One or more internal conductors are provided within the laminate;
In the compression bonding step, a protrusion is formed on the main surface of the laminate at a portion overlapping the one or more internal conductors,
In the protective layer forming step, the protective layer is formed on the positive main surface such that an edge of the protective layer overlaps with the protrusion when viewed in the negative direction of the Z axis.
A method for manufacturing a multilayer board. the protective layer has a ring-shaped edge when viewed in the negative direction of the Z axis,
a mounting electrode is located on the positive principal surface and in a region surrounded by an edge of the ring shape when viewed in the negative direction of the Z axis;
The protrusion has a ring shape along an edge of the ring shape when viewed in the negative direction of the Z axis,
The internal conductor has a ring shape along an edge of the ring shape when viewed in the negative direction of the Z axis.
The method for manufacturing a multilayer substrate according to claim 13. a bonding step of bonding the laminate;
a protective layer forming step of forming a protective layer on the laminated body;
a cutting step of cutting the laminate on which the protective layer is formed;
Equipped with
The laminate has a structure in which a plurality of insulating layers are laminated along the Z axis,
The laminate has a positive principal surface and a negative principal surface located on the negative side of the Z axis from the positive principal surface,
the protective layer covers at least a portion of the positive main surface;
a material of the protective layer is different from a material of the plurality of insulator layers;
one or more internal conductors are provided within the laminate;
In the compression bonding step, a protrusion is formed on the main surface of the laminate at a portion overlapping the one or more internal conductors,
In the protective layer forming step, the protective layer is formed on the positive main surface such that the protective layer covers the protrusion when viewed in the negative direction of the Z axis,
In the cutting step, the laminate is cut so that the protrusion is divided when viewed in the negative direction of the Z axis.
A method for manufacturing a multilayer board.

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