JP2005005435A - Mounting substrate and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin mounting substrate also having excellent dimensional stability, and a manufacturing method for the substrate. <P>SOLUTION: The mounting substrate has a process in which a conductor pattern 12 is formed on one surface of a transfer sheet 10, a process in which an air gap 16 is formed at an insulating layer 14, a process in which the sheet 10 and the layer 14 are laminated with each other so as to hold the pattern 12 and the sheet 10 is removed, a process in which an element 17 is housed in the air gap 16 while being electrically connected to the pattern 12, and a process in which external terminals 22 electrically connected to the element 17 are joined with the reverse surface of the connecting surface of the element 17 in the pattern 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mounting substrate in which a conductor pattern is formed by a transfer method using a transfer sheet, and a method for manufacturing the same. More specifically, an element is mounted on one surface of a one-layer conductor pattern and the other surface on the opposite side. The present invention relates to a mounting substrate in which external terminals are bonded to each other and a manufacturing method thereof.
[0002]
[Prior art]
In recent years, as electronic devices such as mobile phones, PDAs (Personal Digital Assistants), and notebook computers have become smaller and more sophisticated, it is indispensable to mount high-density electronic components. Conventionally, high-density mounting of electronic components has been promoted by making finer pitches of component terminals by miniaturization of electronic components, miniaturization of conductor patterns on a wiring board on which electronic components are mounted, and the like.
[0003]
In recent years, the development of multilayer wiring that enables three-dimensional wiring routing has been promoted, and further, elements such as chip resistors, chip capacitors, or semiconductor bare chips are incorporated in the multilayer wiring board. Thus, development of an element mounting board that further improves the mounting efficiency is also underway.
[0004]
As a method for forming a conductor pattern on a wiring board, a transfer method using a transfer sheet is conventionally known. The manufacturing process of the wiring substrate by this transfer method mainly includes a pattern forming step of forming a conductor pattern on one surface of the transfer sheet, and the formed conductor pattern is bonded to the insulating layer together with the transfer sheet, and then the transfer sheet is peeled off. Pattern transfer process.
[0005]
As this type of conventional technology, for example, Patent Document 1 is known. Hereinafter, a conventional method for manufacturing a mounting substrate will be described with reference to FIG.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-107445
First, as shown in FIG. 10A, a wiring board in which the conductor pattern 2 is formed on the surface of the insulating base 1 is prepared or prepared.
[0008]
Next, as shown in FIG. 10B, an insulating slurry 3 is applied to the surface of the insulating base material 1 to form the insulating layer 3.
[0009]
Next, as shown in FIG. 10C, a via hole 4 communicating with the conductor pattern 2 is formed in the insulating layer 3 by laser processing or the like, and a conductive paste 5 is filled in the formed via hole 4.
[0010]
Next, as shown in FIG. 10 (d), another conductor pattern 6 previously formed on the transfer sheet 7 is transferred to the insulating layer 3, and two conductors are passed through the conductive paste 5. Connect patterns 2 and 6.
[0011]
The transfer sheet 7 is mainly composed of a synthetic resin material such as polyethylene terephthalate (PET). The conductor pattern 6 is formed by patterning a conductor layer adhered or deposited on the transfer sheet 7 into a predetermined shape by a wet etching method. The transfer of the conductor pattern 6 from the transfer sheet 7 to the insulating layer 3 is performed using a difference in adhesion between the conductor pattern 6 and the insulating layer 3 and the transfer sheet 7.
[0012]
[Problems to be solved by the invention]
In the above conventional example, when an element is mounted on a conductor pattern and an external terminal for rearranging and drawing out the electrode pad of the element is to be formed, two conductor patterns connected by vias are required. There is a limit to reducing the thickness of the entire mounting board.
[0013]
The present invention has been made in view of the above-described problems, and an object thereof is to provide a mounting substrate that is thin and excellent in dimensional stability and a method for manufacturing the same.
[0014]
[Means for Solving the Problems]
In solving the above problems, in the mounting substrate of the present invention, the conductor pattern transferred from the transfer sheet is bonded to an insulating layer having a gap, and the element is accommodated in the gap by being electrically connected to the conductor pattern. In the conductor pattern, an external terminal that is electrically connected to the element is bonded to the surface opposite to the connection surface of the element.
[0015]
In order to solve the above-described problems, the mounting substrate manufacturing method of the present invention includes a step of forming a conductor pattern on one surface of a transfer sheet, a step of forming a void in an insulating layer, and a conductor pattern. After the transfer sheet and the insulating layer are bonded to each other, a pattern transfer process for removing the transfer sheet, a process of electrically connecting to the conductor pattern and accommodating the element in the gap, and a connection surface of the element in the conductor pattern And a step of bonding an external terminal electrically connected to the element to the opposite surface.
[0016]
In the present invention, the conductor pattern and the insulating layer are formed in independent processes, and then bonded to each other. If the transfer sheet supporting the conductor pattern is peeled off, the insulating layer is bonded to the conductor pattern. The entire opposite side of the surface is exposed. The other surface of the conductor pattern is exposed in the gap of the insulating layer. Accordingly, by bonding elements or external terminals to the exposed surfaces, a mounting substrate in which elements or external terminals are bonded to the front and back surfaces of the one-layer conductor pattern is obtained, and the two-layer conductor pattern has vias. The mounting substrate can be made thinner than the structure connected via the connector.
[0017]
In addition, you may join an element also to the surface where an external terminal is joined in a conductor pattern. Alternatively, a full grid may be achieved by joining more external terminals in place of the element.
[0018]
Also, a stack structure in which a plurality of mounting boards are stacked can be used. Specifically, the external terminals of a mounting board are stacked so as to pass through the insulating layer of another mounting board and be bonded to the conductive pattern of the mounting board, and the conductor patterns of the stacked mounting boards are stacked, or The elements are electrically connected.
[0019]
The transfer sheet functions as a support for maintaining the flatness of the conductor pattern and improving handling properties. Therefore, it is configured to have mechanical properties such as strength and material properties such as heat-resistant temperature to meet this requirement.
[0020]
The transfer sheet is finally left separated from the conductor pattern. It is preferable to have a release layer for facilitating the separation. As a peeling layer, the structure which laminated | stacked the several metal layer is mentioned, for example. In the case of this configuration, for example, there is an advantage that no dimensional change or alteration occurs even after a heating process of about 300 ° C.
[0021]
Moreover, as a structure of another peeling layer, the resin layer by which the mold release agent was apply | coated to the predetermined site | part of the surface which should be peeled is mentioned. Furthermore, a thermal foam layer may be used as another release layer. In this case, the transfer support can be peeled by foaming the thermal foam layer by heat treatment to a predetermined temperature.
[0022]
Alternatively, the transfer sheet may be dissolved and separated from the conductor pattern without providing a release layer.
[0023]
Further, if the transfer sheet is made conductive, a fine pitch conductor pattern can be formed using a pattern plating technique based on an additive method.
[0024]
In addition, if the base of the external terminal that functions as a joint to another substrate is surrounded by a ring-shaped resin material, the joint strength of the external terminal with a small size can be reduced especially as the number of pins increases. It can be reinforced with a resin material.
[0025]
The reinforcing resin material does not cover the entire external terminal, but surrounds the base of the external terminal in a ring shape, so that it is possible to perform repairs to replace those in which defects or abnormalities are detected after joining. Also, the molten resin material tends to get wet into the base of the external terminal in a fillet shape. Here, the fillet shape is a shape in which the thickness of the resin material gradually decreases as it goes from the base portion of the external terminal to the tip portion side. When reinforced with such a fillet-shaped resin material, the thermal stress applied to the external terminal is dispersed without being applied to a single point, so that high bonding reliability is obtained. The fillet shape can be easily realized by a heating reflow apparatus and heating conditions that are generally performed conventionally.
[0026]
Moreover, it is preferable that the said resin material surrounding the base part of an external terminal is formed on the planarization layer which fills the conductor pattern made into the mutually flush surface, and these conductor patterns. If the supply location of the resin material is flat and there is no unevenness, the resin material will not flow into the recess, and even if the supply amount of the resin material is reduced in order to suppress the warping of the mounting substrate, more resin material Can be used for wetting to the base of the external terminal, and can be reinforced with a resin material having a stable height necessary for securing the strength of the joint.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
Hereinafter, a method for manufacturing a mounting board and a mounting board according to a first embodiment as an example of the present invention will be described.
[0028]
(Process of FIG. 2A)
A release layer 11 is formed on one surface of the transfer sheet 10. FIG. 3 shows details of the structure of the laminate.
[0029]
The transfer sheet 10 is made of Cu, for example, and is configured to have mechanical properties or material properties required for handling. The thickness is about 140 μm, for example.
[0030]
The release layer 11 is composed of two metal layers 11a and 11b. A Cr layer (for example, 0.01 μm thick) 11a is laminated on the transfer sheet 10, and a (Ni—Co) layer (for example, 0.15 μm thick) 11b is laminated on the Cr layer 11a. Both are formed by electroplating using the transfer sheet 10 as a power feeder.
[0031]
The Cr layer 11a and the (Ni—Co) layer 11b have a characteristic that metal bonding does not occur even at a temperature of about 320 ° C., for example. In this case, peeling is possible at the boundary between the Cr layer 11a and the (Ni—Co) layer 11b.
[0032]
(Step of FIG. 2B)
A conductor pattern 12 is formed on the release layer 11. Specifically, first, after forming a photoresist film on the surface of the (Ni—Co) layer 11b, which is the surface of the release layer 11, the photoresist film is exposed and developed to form the photoresist film in a desired shape. A plating resist (not shown) is formed by patterning.
[0033]
Subsequently, the transfer sheet 10 is immersed in a copper electrolytic bath and connected to the cathode electrode to deposit the conductor pattern 12 as a copper electroplating film, and then the plating resist is removed.
[0034]
In general, compared to a method (subtractive method) in which unnecessary portions of a conductive film are removed by wet etching and a conductive pattern is formed (subtractive method), a conductive pattern is formed by depositing a conductive film only in necessary portions by electroplating ( Since the additive method can form a finer pattern, according to the present embodiment, the fine pitch conductor pattern 12 having a line and space (L / S) of, for example, 10 μm / 10 μm can be formed with high accuracy. can do.
[0035]
In addition, since the conductive pattern 12 is formed on the transfer sheet 10 made of Cu that is thicker and has a smaller dimensional change than a resin film, the handling property is improved, and even when the conductive pattern 12 is thin, warping is suppressed. And dimensional accuracy can be stabilized.
[0036]
(Step of FIG. 2C)
A paste-like insulating resin material is applied on the release layer 11 so as to cover the conductor pattern 12, the resin material is heated and cured, and then polished to expose the surface of the conductor pattern 12. As a result, a flattened layer 13 that fills the space between the conductor patterns 12 and is flush with the surface of the conductor pattern 12 is formed on the release layer 1, and one surface of the transfer sheet 10 is flattened.
[0037]
(Step of FIG. 4D)
The conductor pattern 12 is bonded to the insulating layer 14 together with the transfer sheet 10. The insulating layer 14 is made of, for example, resin or ceramic, and an insulating adhesive layer 15 is laminated on one surface side thereof.
[0038]
The insulating layer 14 and the adhesive layer 15 are formed with a gap 16 penetrating in the thickness direction. For example, known drilling techniques such as machining using a drill or a router, die punching, and laser machining can be applied.
[0039]
The adhesive layer 15 is adhered to the same surface of the conductor pattern 12 and the planarizing layer 13, and the transfer sheet 10 and the insulating layer 14 are bonded to each other. For example, bonding is performed by a hot press. As the adhesive layer 15, for example, an epoxy type material having a low fluidity and a high shape maintaining property is used so that the adhesive layer 15 does not flow out into the gap 16 at this time.
[0040]
(Step of FIG. 4E)
The element 17 is accommodated in the gap 16. Conductive bumps 17 a are formed on the electrode pads formed on the lower surface of the element 17, and the conductive bumps 17 a are heated while being pressed against the surface of the conductor pattern 12 to be metal-bonded. Thereby, the element 17 is electrically connected to the conductor pattern 12 via the conductive bump 17a. After the element 17 is mounted, the gap portion 16 is filled with the underfill resin material 18 to protect the joint portion between the element 17 and the conductor pattern 12.
[0041]
In addition, after bonding solder, tin, nickel, gold | metal | money, silver, etc. to the surface of the conductive bump 17a and the surface of the conductor pattern 12 to which this is joined, you may join both. In this case, the wettability and bondability between the conductive bumps 17a and the conductor pattern 12 can be improved, bonding can be performed at a lower load and lower temperature, and damage to the element 17 can be reduced.
[0042]
(Step of FIG. 5F)
The transfer sheet 10 is peeled off. Specifically, the peeling layer 11 shown in FIG. 3 peels at the boundary surface between the Cr layer 11a and the (Ni—Co) layer 11b. For example, the boundary surface is cut off and peeled off. The Cr layer 11a and the (Ni—Co) layer 11b can be easily peeled off without being metal-bonded to each other even when subjected to thermal stress by hot pressing during the bonding process with the insulating layer 14.
[0043]
(Step of FIG. 5G)
The (Ni—Co) layer 11b remains on the flush surfaces of the conductor pattern 12 and the planarizing layer 13, but this is removed by wet etching with, for example, a hydrogen peroxide-based etchant.
[0044]
(Step of FIG. 6H)
The resin material 20 is supplied onto the same surface of the conductor pattern 12 and the planarization layer 13 from which the transfer sheet 10 and the release layer 11 have been removed. As a method of supplying the resin material 20, for example, a method of applying a liquid resin material diluted with a solvent by a spray method and drying, a method of supplying a paste-like resin material by printing or a spin coating method, or complete curing. For example, there is a method of supplying by sticking a film-like resin material in a B-stage state, but the method is not particularly limited as long as the method can supply a required amount uniformly. Here, the necessary amount is an amount that can make a fillet, which will be described later, a height necessary for securing the bonding strength.
[0045]
In the present embodiment, for example, a resin material 20 having ultraviolet curability and containing an activator is used. Specifically, a resin material 20 in which a phenol novolak containing at least an acryloyl group or a methacryloyl group, a resin that functions as a curing agent, and a photopolymerization initiator is used. The phenolic hydroxyl group of phenol novolac functions as an activator, and by its reducing action, it removes dirt such as oxides on the solder and metal surface, and prevents reoxidation, and is a joint surface of an external terminal described later. The wettability of solder and molten metal to the surface of the conductor pattern 12 is enhanced. This action of the activator is lost when the resin material 20 is cured.
[0046]
(Step of FIG. 6I)
In the resin material 20, a resist mask 21 is formed by known photolithography and etching which are portions of the conductor pattern 12 that serve as joint surfaces of external terminals. Other parts are exposed. In this state, ultraviolet rays are irradiated.
[0047]
Thereby, the resin material 20a of the part which is not covered with the resist mask 21 is hardened. The resin material 20a functions as an insulating protective film (solder resist) that prevents a short circuit between the conductor patterns 12 or between the conductor patterns 12 and the external terminals. Therefore, it is not necessary to separately form a solder resist, and the process can be simplified.
[0048]
(Step of FIG. 6J)
After the resist mask 21 is removed, the spherical external terminals 22 are arranged on the conductor pattern 12 on which the resin material 20 that remains uncured is present. The material of the external terminal 22 is not particularly limited, and a known alloy composition such as Sn—Pb, Sn—Ag, Sn—Ag—Cu, Sn—Zn, Sn—Zn—Bi is used.
[0049]
Further, as shown in FIG. 9, for example, an external terminal 48 including a core portion 48 a made of a resin material may be used. The surface of the core portion 48a is covered with a conductive surface layer portion composed of a metal layer 48b and a solder plating layer 48c. Since the external stress is received by the entire external terminal by the included core portion 48a, the stress on the joint portion is reduced. The core portion 48a only needs to have stress relaxation properties and have a uniform particle diameter, and is not limited to resin and may be rubber or metal.
[0050]
Next, the mounting board on which the external terminals 22 are mounted is put into a reflow furnace and heated. The external terminals 22 arranged on the conductor pattern 12 come into contact with the surface of the conductor pattern 12 due to their own weight, and are further heated and melted so that the uncured resin material 20 can be applied and wetted on the surface of the conductor pattern 12. It spreads. Thereby, the external terminal 22 and the conductor pattern 12 are metal-bonded.
[0051]
At the time of this reflow, since the resin material 20 where the external terminals 22 are arranged is uncured, it has a metal activation action by the above-mentioned activator, and the external terminals 22 can be connected without applying a separate flux. The wettability with the conductor pattern 12 can be improved and the bondability can be improved.
[0052]
In addition, due to the heating at this time, the uncured resin material 20 is wetted in a ring shape at the base portion of the external terminal 22 (the portion on the joint portion side with the conductor pattern 12), as shown in FIG. After forming the fillet 23 surrounding the base, it is cured by receiving further heating.
[0053]
Since the planarization layer 13 is filled between the conductor patterns 12 and the surface to which the external terminals 22 are joined is planarized, the uncured resin material 20 flows between the conductor patterns 12 when the fillet 23 is formed. Therefore, the amount of wetting to the base portion of the external terminal 22 can be increased accordingly.
[0054]
As a result, the height of the fillet can be increased (when the supply amount of the reinforcing resin material is the same) as compared with the case where there is a step between the bonding surface and the insulating layer surface and the surface is not flattened, The bonding strength of the external terminal 22 can be improved.
[0055]
The resin material 20 having photocurability and further containing an activator tends to have a relatively large cure shrinkage due to its characteristics that it cannot contain much filler. Therefore, it is desirable to reduce the supply amount of the resin material 20 as much as possible in order to suppress warping of the mounting substrate. In this embodiment, since the supply surface of the resin material 20 is flattened as described above, the fillet height necessary for securing the strength can be realized while the supply amount is small. The fillet height necessary for securing the strength varies depending on the material of the resin material and the material and size of the external terminal 22, for example, 10% or more of the height of the external terminal 22 is sufficient.
[0056]
Finally, as shown in FIG. 1, a mounting substrate 25 in which the element 17 is mounted on one surface of the single-layer conductor pattern 12 and the external terminal 22 is bonded to the other surface on the opposite side, as shown in FIG. Is obtained.
[0057]
Since the external terminal 22 is bonded to the surface opposite to the surface on which the element 17 is mounted, it can be disposed at a position overlapping the element 17, that is, a full grid using the entire back surface of the mounting substrate 25 is possible. Thereby, even if the number of electrode pads of the element 17 is large, a large number of external terminals 22 can be drawn out (rearranged) with a pitch larger than the pitch between the electrode pads. Alternatively, the size of each external terminal 22 can be increased, and the bonding reliability with another substrate can be increased via the external terminal 22.
[0058]
Further, the planar dimensions can be reduced as compared with a structure in which external terminals are formed on the left and right sides of the element 17 so as to avoid the element 17 on the mounting surface side of the element 17. Further, in the structure in which the external terminal is formed on the mounting surface side of the element 17, it is necessary to form a through hole reaching the conductor pattern 12 in the insulating layer 14 and embed the external terminal in the through hole, so that workability is poor. Although this may cause a decrease in yield, in the present embodiment, since it is arranged as it is on the exposed surface of the conductor pattern 12, it can be performed with good workability.
[0059]
In forming the conductor pattern 12, a fine and flat transfer sheet 10 is used as a starting material, and fine plating of 10 μm or less, which is impossible with a normal semiconductor interposer substrate or TAB (tape automated bonding) tape, is performed by pattern plating using an additive method. The conductor pattern 12 can be formed.
[0060]
Furthermore, since the transfer sheet 10 has mechanical strength and material characteristics that do not cause problems in handling properties and dimensional changes, a very thin conductor pattern 12 can be formed with high accuracy. Finally, the transfer sheet 10 is peeled off, and as a result, a thin mounting substrate 25 of 100 μm or less is obtained.
[0061]
Further, since the transfer sheet 10, the release layer 11, and the conductor pattern 12 are all metal, there are restrictions on the selection of materials, heating, and pressing conditions during hot pressing in the bonding process with the insulating layer 14 shown in FIG. 4D. Not receive.
[0062]
[Second Embodiment]
Next, a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same component as the said 1st Embodiment, and the detailed description is abbreviate | omitted.
[0063]
As shown in FIG. 7, in the mounting substrate 35 according to the present embodiment, the external terminal 22 and another element 37 are mounted on the surface opposite to the mounting surface of the element 17. The element 37 is electrically connected to the conductor pattern 12 via conductive bumps 37a formed on the electrode pads. An underfill resin 38 is filled to protect the joint between the conductive bump 37a and the conductor pattern 12.
[0064]
[Third Embodiment]
Next, a third embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same component as the said 1st Embodiment, and the detailed description is abbreviate | omitted.
[0065]
In the present embodiment, as shown in FIG. 8, through holes are formed in the insulating layer 14 of the mounting board obtained in the first embodiment to form a mounting board 25 ′ for stacking. Three mounting boards 40a to 40c are overlapped with each other.
[0066]
The external terminal 22 of the mounting board 40c enters the through hole formed in the insulating layer 14 of the mounting board 25 ′ and is joined to the conductor pattern 12 of the mounting board 25 ′, and the external terminal 22 of the mounting board 40b is connected to the mounting board 25b. 40c enters the through-hole formed in the insulating layer 14 and is joined to the conductor pattern 12 of the mounting substrate 40c. The external terminal 22 of the mounting substrate 40a is in the through-hole formed in the insulating layer 14 of the mounting substrate 40b. It enters and is joined to the conductor pattern 12 of the mounting substrate 40b. More layers may be stacked by stacking more mounting boards.
[0067]
Further, if an external terminal 48 including a core portion 48a made of, for example, a resin material as shown in FIG. 9 is used, the connection through the through hole of the insulating layer 14 can be ensured, and each external terminal The height variation can be absorbed, and the gap between the mounting boards can be made uniform. For example, when solder is used as the external terminal, the height of the external terminal varies due to the flow of solder, etc., causing the mounting board to tilt, and the external terminal does not reach the conductor pattern exposed at the bottom of the through hole. There is a risk of connection failure.
[0068]
As mentioned above, although each embodiment of this invention was described, of course, this invention is not limited to these, A various deformation | transformation is possible based on the technical idea of this invention.
[0069]
The transfer sheet is not limited to metal, and may be glass or a semiconductor wafer. In this case, for example, a Ni layer, a (Ni-P) layer, a Cr layer, or the like is formed as a release layer on the transfer sheet by electroless plating or sputtering.
[0070]
Further, the release layer is not limited to the configuration shown in FIG. 3, for example, it may be configured with one Cr layer, one Ni layer, or two of a Cr layer and a (Ni—Cr) layer. A layer structure or a two-layer structure of a Cr layer and a Ni layer may be used.
[0071]
The transfer sheet 10 may be peeled off after being bonded to the insulating layer 14 and before the element 17 is mounted.
[0072]
The element is not limited to a bare chip, but may be a packaged component, a chip resistor, a chip capacitor, or the like.
[0073]
【The invention's effect】
As described above, according to the present invention, the conductor pattern transferred from the transfer sheet is bonded to the insulating layer having a gap, electrically connected to the conductor pattern, and the element is accommodated in the gap. Since external terminals that are electrically connected to the element are joined to the opposite surface of the element connection surface in the pattern, the two-layer conductor pattern and the via connecting the two layers are not formed. On the other hand, the element and the external terminal can be mounted on the opposite surfaces, and the mounting substrate can be thinned. Further, by bonding the external terminals to the surface where the element is not mounted, more external terminals can be arranged without being blocked by the element.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a mounting board according to a first embodiment of the present invention.
FIG. 2 is a manufacturing process sectional view of the mounting board according to the first embodiment;
3 is an enlarged cross-sectional view of a main part in FIG. 2. FIG.
FIG. 4 is a manufacturing process sectional view subsequent to FIG. 2;
FIG. 5 is a manufacturing process sectional view following FIG. 4;
6 is a manufacturing process sectional view subsequent to FIG. 5;
FIG. 7 is a cross-sectional view of a mounting board according to a second embodiment of the present invention.
FIG. 8 is a cross-sectional view of a mounting board according to a third embodiment of the present invention.
FIG. 9 is a cross-sectional view of a modified example of the external terminal.
FIG. 10 is a cross-sectional view of a manufacturing process of a conventional mounting board.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Transfer sheet, 11 ... Release layer, 12 ... Conductor pattern, 13 ... Planarization layer, 14 ... Insulating layer, 16 ... Gap part, 17 ... Element, 22 ... External terminal, 23 ... Fillet, 25 ... Mounting board, 25 '... Mounting substrate, 35 ... Mounting substrate, 37 ... Element, 40a-40c ... Mounting substrate.

Claims (9)

The conductor pattern transferred from the transfer sheet is bonded to an insulating layer having a gap,
An element is accommodated in the gap portion electrically connected to the conductor pattern,
An external terminal that is electrically connected to the element is bonded to a surface opposite to the connection surface of the element in the conductor pattern. The mounting substrate according to claim 1, wherein the conductive pattern is a plating film formed by pattern plating on the transfer sheet having conductivity. The mounting substrate according to claim 1, wherein a base portion of the external terminal is surrounded by a ring-shaped resin material. The said resin material surrounding the base part of the said external terminal is formed on the planarization layer which fills the said conductor pattern and these conductor patterns which were mutually flush | planar, and these conductor patterns are characterized by the above-mentioned. Mounting board. 2. The mounting substrate according to claim 1, wherein an element is bonded to the opposite surface of the conductor pattern by being electrically connected to the conductor pattern. A mounting board in which a plurality of the mounting boards are stacked,
2. The plurality of mounting boards are stacked by the external terminals penetrating through the insulating layer of another mounting board and joined to the conductor pattern of the other mounting board. The mounting board described. Forming a conductor pattern on one surface of the transfer sheet;
Forming a void in the insulating layer;
A pattern transfer step of removing the transfer sheet after the transfer sheet and the insulating layer are bonded together so as to sandwich the conductor pattern;
Electrically connecting to the conductor pattern and accommodating the element in the gap,
A method for manufacturing a mounting board, comprising: bonding an external terminal electrically connected to the element to a surface opposite to a connection surface of the element in the conductor pattern. The method for manufacturing a mounting substrate according to claim 7, wherein the transfer sheet has conductivity, and the conductive pattern is formed on the transfer sheet by pattern plating using an electroplating method. A step of forming an insulating flattening layer so as to fill the gap between the conductor patterns and be flush with the surface of the conductor pattern after forming the conductor pattern on the transfer sheet. Item 8. A method for manufacturing a mounting board according to Item 7.

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