JP6744072B2 - Manufacturing method of mounting board - Google Patents

Description

The present invention relates to a mounting substrate and a manufacturing method thereof, and more particularly to a mounting substrate having a metal material layer filled in a through hole and a manufacturing method thereof.

BACKGROUND ART Conventionally, a substrate for an IC (Integrated Circuit) chip formed by using an alumina sintered body, a glass ceramic or the like, and a package or the like mounted with the substrate have been provided. 2. Description of the Related Art In recent years, as the functionality of semiconductor elements and IC chips equipped with the semiconductor elements has increased, the amount of heat generated by the IC chips and the like has increased, and excellent heat dissipation is required for substrates and packages. Therefore, for example, a through hole formed so as to reach the main surface on the side opposite to the main surface of the substrate for the IC chip on which the semiconductor element is mounted is filled with, for example, a paste-like metal material. A heat dissipation member (heat dissipation via) is provided.

For example, Japanese Patent Laying-Open No. 2006-351738 (Patent Document 1) discloses an RF (Radio Frequency) module configured by laminating a plurality of insulating substrates. A heat dissipation via is formed in the laminated insulator substrate forming the RF module so as to penetrate the laminated insulator substrate from the component mounting surface to the back surface which is the opposite surface. The heat dissipation vias are formed on the first via portion formed on the lowermost first insulator plate of the plurality of laminated insulator substrates and the second insulator plate laminated on the first insulator plate. And a second via portion that is continuous with the first via portion.

JP, 2006-351738, A

In Japanese Unexamined Patent Publication No. 2006-351738, a first via portion and a second via portion, which are respectively formed by laminating a plurality of insulator substrates, are laminated, and then the first and second via portions are laminated. The heat dissipation member is formed by filling the inside with the conductive material all at once. In this case, the conductive material has to be filled so as to fill the whole of the thick and wide through hole by one filling step. For this reason, it is very difficult to supply a conductive material to the entire surface so that there are no voids and dents and to dry it without spots. If the insulating substrate is sintered with the dry spots remaining, a shape abnormality such as warping of the insulating substrate occurs after sintering. As a result, the contact between the IC chip, which is a heat source, and the surface of the heat dissipation member on which it is mounted is reduced, and the heat dissipation effect of the heat dissipation member may be reduced.

Further, for example, in JP-A-2006-351738, the size of the first via portion in plan view is relatively smaller than the size of the second via portion in plan view. Therefore, there is a possibility that the heat dissipation efficiency may be reduced especially in the first via portion.

The present invention has been made in view of the above problems, and an object thereof is to provide a mounting board having a heat dissipation member having a higher heat dissipation property and a method for manufacturing the same.

In the method for manufacturing a mounting substrate of the present invention, first, a transfer sheet having a ceramic sheet having through holes formed therein and a dried metal material layer in holes is prepared. A film-like material is attached to one main surface of the ceramic sheet. The transfer substrate is faced such that the in-hole metal material layer faces the other main surface of the ceramic sheet, which is opposite to the other main surface. By pressing the transfer base material and the ceramic sheet, the in-hole metal material layer is transferred into the through hole. By repeating the step of preparing the ceramic sheet, the step of adhering, the step of facing, and the step of transferring, a plurality of ceramic sheets to which the in-hole metal material layer has been transferred are prepared in the through holes. By laminating, pressurizing, and integrating the plurality of ceramic sheets so that the respective layers of the metallic material in the holes of the plurality of ceramic sheets overlap each other, a heat dissipation member made of the layer of metallic material in the hole is formed. It After the transferring step and before the laminating, pressing and integrating steps, the film-like material attached to one main surface of each of the plurality of ceramic sheets is peeled off from the ceramic sheets.

In the method for manufacturing a mounting substrate of the present invention, first, a transfer sheet having a ceramic sheet having a through hole formed therein and a dried first hole metal material layer is prepared. The first film-like material is attached to one main surface of the ceramic sheet. The transfer substrate is faced so that the first in-hole metal material layer faces the other main surface of the ceramic sheet on the side opposite to the one main surface. By pressing the transfer base material and the ceramic sheet, the first in-hole metal material layer is transferred into the through holes. After the transferring step, another ceramic sheet having through holes formed on the other main surface of the ceramic sheet is laminated so that the through holes overlap each other. After the step of stacking the ceramic sheets, the through hole of the stacked ceramic sheets is filled with the second in-hole metal material layer.

In the method for manufacturing a mounting board of the present invention, first, a ceramic sheet having a through hole is prepared. The first film-like material is attached to the other main surface of the ceramic sheet on the side opposite to the one main surface so as to close the through hole along the one main surface of the ceramic sheet. To be A dried extra-hole metal material layer is formed on one main surface of the ceramic sheet so as to cover a portion of the first film-like material that closes the inside of the through hole. Another ceramic sheet having through holes formed on one main surface of the ceramic sheet is laminated so that the through holes overlap each other. In the laminating step, the through-holes of the laminated ceramic sheets are filled with the in-hole metal material layer.

According to the present invention, since the heat dissipation member extends in a column shape from one main surface of the mounting board to the other main surface, the heat dissipation efficiency of the heat dissipation member can be further enhanced.

According to the manufacturing method of the present invention, the dried dry metal material layer is transferred into each through hole of each ceramic sheet, and they are integrated by laminating and pressing. Therefore, the deformation of the heat dissipation member is suppressed, the deterioration of the contact property with the IC chip or the like is suppressed, and the heat dissipation efficiency can be further enhanced.

FIG. 3 is a schematic cross-sectional view showing the configuration of the mounting board according to the first embodiment. FIG. 7 is a schematic cross sectional view showing a first step of the method of manufacturing the mounting substrate in the first embodiment. FIG. 7 is a schematic cross sectional view showing a second step of the method of manufacturing the mounting substrate in the first embodiment. FIG. 7 is a schematic cross sectional view showing a third step of the method for manufacturing the mounting substrate in the first embodiment. FIG. 7 is a schematic cross sectional view showing a fourth step of the method of manufacturing the mounting substrate in the first embodiment. FIG. 9 is a schematic cross sectional view showing a fifth step of the method for manufacturing the mounting substrate in the first embodiment. FIG. 7 is a schematic cross sectional view showing a sixth step of the method for manufacturing the mounting substrate in the first embodiment. FIG. 13 is a schematic cross sectional view showing a seventh step of the method for manufacturing the mounting substrate in the first embodiment. FIG. 13 is a schematic cross sectional view showing an eighth step of the method of manufacturing the mounting board in the first embodiment. FIG. 9 is a schematic cross sectional view showing a ninth step of the method for manufacturing the mounting substrate in the first embodiment. FIG. 16 is a schematic cross sectional view showing a tenth step of the method for manufacturing the mounting substrate in the first embodiment. FIG. 14 is a schematic cross sectional view showing an eleventh step of the method for manufacturing the mounting substrate in the first embodiment. FIG. 13A is a schematic plan view of a mode in which a semiconductor chip is mounted on a mounting substrate formed by the manufacturing method according to the first embodiment, and a schematic cross-sectional view of a portion taken along line XIIIB-XIIIB of FIG. 13B is a schematic cross-sectional view of FIG. 13A along the line XIIIC-XIIIC. FIG. 16 is a schematic plan view showing a region where the data of FIG. 15 is measured in the mounting substrate formed by the manufacturing method in the first embodiment and the mounting substrate of the comparative example. It is data which shows the aspect of the metal material with which the through hole of the part along the XV-XV line of FIG. 14 was filled up by the printing method and the transfer method. FIG. 16 is a schematic cross sectional view showing a first step of the method of manufacturing the mounting substrate in the second embodiment. FIG. 9 is a schematic cross sectional view showing a second step of the method for manufacturing the mounting substrate in the second embodiment. FIG. 16 is a schematic cross-sectional view showing a first step of a method of manufacturing a mounting substrate in the first example of the third embodiment. FIG. 27 is a schematic cross sectional view showing a second step of the method for manufacturing the mounting substrate in the first example of the third embodiment. FIG. 27 is a schematic cross sectional view showing a third step of the method for manufacturing the mounting substrate in the first example of the third embodiment. FIG. 19 is a schematic cross sectional view showing a fourth step of the method for manufacturing the mounting substrate in the first example of the third embodiment. FIG. 25 is a schematic cross sectional view showing a fifth step of the method for manufacturing the mounting substrate in the first example of the third embodiment. FIG. 19 is a schematic cross sectional view showing a first step of a method of manufacturing a mounting substrate in the second example of the third embodiment. FIG. 16 is a schematic cross-sectional view showing the structure of a mounting board according to the fourth embodiment. FIG. 16 is a schematic cross sectional view showing a first step of the method of manufacturing the mounting substrate in the fourth embodiment. FIG. 13 is a schematic cross sectional view showing a second step of the method of manufacturing the mounting substrate in the fourth embodiment. FIG. 16 is a schematic cross sectional view showing a third step of the method of manufacturing the mounting substrate in the fourth embodiment. FIG. 19 is a schematic cross sectional view showing a fourth step of the method of manufacturing the mounting substrate in the fourth embodiment. FIG. 13 is a schematic cross sectional view showing a fifth step of the method for manufacturing the mounting substrate in the fourth embodiment. FIG. 16 is a schematic cross sectional view showing a sixth step of the method for manufacturing the mounting substrate in the fourth embodiment. FIG. 19 is a schematic cross sectional view showing a seventh step of the method for manufacturing the mounting substrate in the fourth embodiment. FIG. 19 is a schematic cross sectional view showing an eighth step of the method of manufacturing the mounting substrate in the fourth embodiment. FIG. 19 is a schematic cross sectional view showing a ninth step of the method of manufacturing the mounting substrate in the fourth embodiment. FIG. 19 is a schematic cross sectional view showing a tenth step of the method for manufacturing the mounting substrate in the fourth embodiment. It is a schematic sectional drawing which shows the 11th process of the manufacturing method of the mounting substrate in Embodiment 4. FIG. 19 is a schematic cross sectional view showing a twelfth step of the method for manufacturing the mounting substrate in the fourth embodiment. It is a schematic sectional drawing which shows the 13th process of the manufacturing method of the mounting substrate in Embodiment 4. 38A is a schematic plan view of a mode in which a semiconductor chip is mounted on a mounting substrate formed by the manufacturing method according to the fourth embodiment, and a schematic cross-sectional view of a portion along the line XXXVIIIB-XXXVIIIB in FIG. 38B is a schematic cross-sectional view of a portion along line XXXVIIIC-XXXVIIIC in FIG. 39A is a schematic plan view of the mounting substrate in Embodiment 5, FIG. 39A is a schematic cross-sectional view of a portion along the line XXXIXB-XXXIXB, and FIG. 39A is a line XXXIXC-XXXIXC. It is a schematic sectional drawing (C) of a portion along. FIG. 40 is a schematic plan view showing a mode in which the mounting board shown in FIG. 39(A) is normalized so as to have a square shape with the same area. 41 is a graph showing a result of plotting the relative value of the flatness of the surface of the heat dissipation via with respect to the length of one side of the mounting substrate which is regarded as a square as in FIG. 40.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
First, as the configuration of the mounting board of the present embodiment, particularly the configuration of the heat dissipation member formed on the mounting board will be described with reference to FIG.

Referring to FIG. 1, the mounting substrate 10 according to the present embodiment is formed by firing a plurality (six in FIG. 1) of ceramic green sheets, which will be described later, by laminating and pressing. It was formed. Actually, the ceramic substrate 11 is integrated and does not have a boundary between the laminated layers, but here, for convenience of description, from the viewpoint of showing how the ceramic substrate 11 is composed of a plurality of layers, The boundaries between the layers of the laminated ceramic green sheets are shown by dotted lines in FIG. The ceramic substrate 11 has a flat plate shape, and has a rectangular shape in a plan view, for example, although not shown.

The ceramic substrate 11 is laminated such that the upper main surface of one ceramic green sheet is in contact with the lower main surface of the ceramic green sheet directly above, and a plurality of ceramic green sheets are integrated. It has been sintered in. As a result, the mounting substrate 10 having the ceramic substrate 11 as a base is formed. Large-diameter through holes 3b (through holes) are formed in the ceramic substrate 11 so as to extend from the upper main surface of each of the plurality of ceramic green sheets constituting the ceramic substrate 11 to the lower main surface, The large-diameter through hole 3b is filled with the in-hole metal material layer 12a. By laminating and integrating them, a large-diameter through hole 3b (through hole) is formed so as to extend from the upper main surface 1f of the entire ceramic substrate 11 to the lower main surface 1b of the whole. The large-diameter through hole 3b is filled with the in-hole metal material layer 12a.

Further, the outer hole metal material layer 12b is formed on, for example, the upper main surface of each layer of the plurality of ceramic green sheets before being laminated that configures the ceramic substrate 11 so as to cover the inner hole metal material layer 12a in each ceramic green sheet. A pattern is formed.

The plurality of in-hole metal material layers 12a formed on the ceramic substrate 11 have substantially the same size, position and shape in plan view, and the plurality of out-of-hole metal material layers 12b formed on the ceramic substrate 11 in plan view, The position and shape are almost the same. However, the outside metal material layer 12b is slightly larger in size in plan view than the inside metal material layer 11.

Therefore, by laminating the ceramic green sheets, the in-hole metal material layers 12a and the out-hole metal material layers 12b are laminated so as to overlap each other in the formed ceramic substrate 11. A plurality of these overlapping ceramic green sheets are brought into close contact with each other by being pressed on the main surfaces 1f and 1b to be integrated with each other, thereby forming a mounting substrate 10 having a single ceramic substrate 11. Then, in the mounting substrate 10, the plurality of in-hole metal material layers 12a and the out-of-hole metal material layers 12b are in close contact with each other to be integrated, thereby forming the heat dissipation vias 12 as an integrated heat dissipation member. Since the in-hole metal material layer 12a and the out-hole metal material layer 12b are substantially equal in size, the heat dissipation via 12 is basically the entire (from the upper main surface 1f of the ceramic substrate 11 of the mounting substrate 10, They have substantially the same size in a plan view (up to the main surface 1b below the ceramic substrate 11 of the mounting substrate 10).

Since the heat dissipation via 12 has the above-described configuration, the heat dissipation via 12 is formed from the lower main surface 1b (one main surface) of the ceramic substrate 11 forming the mounting substrate 10 to the ceramic substrate 11 forming the mounting substrate 10. Up to the upper main surface 1f (the other main surface), for example, the planar area of the in-hole metal material layer 12a is continuously formed so as to extend vertically in FIG. ing. The in-hole metal material layer 12a constitutes the main body of the heat dissipation via 12, and the out-hole metal material layer 12b has a role of connecting the pair of in-hole metal material layers 12a sandwiched therebetween to be integrated with each other.

The heat dissipation vias 12 generate heat generated by, for example, an IC chip mounted (mounted) on the main surface 1f on the upper side of the ceramic substrate 11 in FIG. 1, and the plurality of in-hole metal material layers 12a and outside-hole metal material layers 12b. The heat is dissipated on the main surface 1b below the ceramic substrate 11 of FIG. Therefore, it is preferable to use a conductive material (metal material) having a high thermal conductivity as the in-hole metal material layer 12a and the out-hole metal material layer 12b.

As will be described later, in addition to these, a small-diameter through hole having a size smaller than that of the large-diameter through hole 3b in plan view and a small-diameter via filling the inside thereof are formed in addition to these, as will be described later. Illustration and description thereof are omitted in FIG. 1. This also applies to the following embodiments.

Next, a method of manufacturing the mounting board 10 according to the present embodiment will be described with reference to FIGS.

Referring to FIG. 2, first, an unsintered ceramic sheet, that is, a ceramic green sheet 1 is prepared. The ceramic green sheet 1 has a thickness of approximately 0.1 mm. Although not shown, the ceramic green sheet 1 has, for example, a rectangular shape in a plan view. The ceramic green sheet 1 is formed by using a powder of a ceramic material such as alumina and using a doctor blade method or the like.

Referring to FIG. 3, at a desired position of ceramic green sheet 1 in a plan view, that is, at a position where heat dissipation via 12 is to be formed, etc., from upper main surface 1f of ceramic green sheet 1 to a lower main surface opposite thereto. A through hole 3 is formed therethrough so as to reach 1b. The through hole 3 has a large diameter through hole 3b and a small diameter through hole 3s, and the small diameter through hole 3s is smaller than the large diameter through hole 3b in plan view. The positions and the numbers of the large-diameter through holes 3b and the small-diameter through-holes 3s are arbitrary, but in FIG. Two are formed on each side.

In FIG. 3, as an example, the large diameter through hole 3b has a substantially circular shape with a diameter larger than 0.6 mm in a plan view, and the small diameter through hole 3s has a diameter smaller than 0.2 mm in a plan view, for example, a substantially circular shape. have. The large-diameter through hole 3b is a through hole for forming the heat dissipation via 12 which serves as a heat dissipation path of the mounting board 10 to be formed. The small-diameter through-hole 3s is a through-hole for forming a small-diameter via that electrically connects the layers of the laminated circuit formed on the mounting substrate 10 to be formed. A well-known drilling machine can be used for processing the through holes 3 in the ceramic green sheet 1.

As a result, the diameter of the in-hole metal material layer 12a that constitutes the heat dissipation via 12 after being finally sintered is 0.6 mm or more in plan view (0.5 mm or more because it shrinks due to sintering). There is. In addition, here, as an example, the through hole 3 will be described as having a circular planar shape (both the large diameter through hole 3b and the small diameter through hole 3s), but the planar shape of the through hole 3 is not limited to this, and for example, it will be described later. As shown in 13, it may be rectangular. Regardless of the planar shape, the maximum size of the in-hole metal material layer 12a in plan view (that is, the diameter if circular, the side length on the long side if rectangular) is 0.5 mm or more. Since the heat dissipation via 12 has a columnar shape, the in-hole metal material layer 12a is entirely formed from the uppermost surface (uppermost layer of the ceramic substrate 11) to the lowermost surface (lowermost layer of the ceramic substrate 11) of the heat dissipation via 12 as described above. The maximum dimension in plan view is 0.5 mm or more. The maximum dimension is more preferably 0.6 mm or more, even more preferably 0.8 mm or more, and even more preferably 1 mm or more.

Referring to FIG. 4, after forming through-hole 3, film-shaped material 4 is attached to, for example, lower main surface 1b (one main surface) of ceramic green sheet 1. The film-shaped material 4 is a flat plate-shaped member having substantially the same size and shape as the ceramic green sheet 1 in a plan view. When supplying the metal material into the through-hole 3 described later, the film-shaped material 4 leaks the supplied metal material to the outside from the main surface 1b side of the ceramic green sheet 1 (falls off to the stage table of the printing machine). It is attached for the purpose of suppressing the above and supporting the metal material from below from the bottom of the ceramic green sheet 1 in a stable manner. It is preferable that the film-shaped material 4 has an adhesive force of, for example, 0.08 N or more and 0.27 N or less for adhering to the ceramic green sheet 1 within a 25 mm width region. The preferable thickness of the film material 4 will be described later.

With reference to FIG. 5, from the upper main surface 1f (the other main surface) in the figure on the side opposite to the main surface 1b on the side where the film-shaped material 4 of the ceramic green sheet 1 is attached, the small-diameter through hole is formed. The small-diameter metal material layer 5 is filled in 3s. A known screen printing method is used for filling the small-diameter metal material layer. As a result, the paste-like metal material is supplied into the small-diameter through-hole 3s, whereby the small-diameter metal material layer 5 is formed.

As the small-diameter metal material layer 5 filled here, a conductive material having high electric conductivity is preferably used. Specifically, the small-diameter metal material layer 5 is a paste-like metal material in which any metal powder selected from the group consisting of silver, a mixture of silver and palladium, and gold is dispersed in a solvent. It is formed by supplying the inside. However, in the present embodiment, as an example, the small-diameter metal material layer 5 is formed of a paste-like metal material in which silver powder is dispersed in a solvent.

Referring to FIG. 6, next, a transfer base material 6 for filling a metal material into a large-diameter through hole 3b larger than the small-diameter through hole 3s is prepared. The transfer base material 6 has, for example, a film-shaped base material 6a, a cushioning material 7, and a transfer metal material layer 2a (in-hole metal material layer), but is not limited thereto.

The film-shaped substrate 6a is formed of a material different from that of the ceramic green sheet 1, and has a rectangular shape, for example, in a plan view, which is not shown, and has substantially the same size and shape as the ceramic green sheet 1. Here, as an example, the film-shaped substrate 6a is formed of a polyester film. The thickness of the film-shaped substrate 6a is preferably about 0.05 mm or more and 0.1 mm or less, and here, as an example, the thickness of the film-shaped substrate 6a is about 0.1 mm.

The transfer metal material layer 2a is at least a partial region (for example, the central portion on the lower main surface of the film-shaped substrate 6a in FIG. 6 and at a position corresponding to the large-diameter through hole 3b at the time of subsequent transfer). ) Is formed by supplying a paste-like metal material in a thin film form by, for example, a known screen printing method. The paste-like metal material supplied here is, for example, a paste-like metal material in which silver powder is dispersed in a solvent. For example, when the large-diameter through hole 3b has a circular planar shape, the transfer metal material layer 2a also has a circular planar shape, although not shown.

The paste-like transfer metallic material layer 2a supplied in a thin film form by printing is dried by being held at a heating temperature of, for example, 50° C. or higher and 60° C. or lower for 15 minutes or longer and 20 minutes or shorter. In this way, the transfer metal material layer 2a can be dried without deforming the film-shaped substrate 6a. The thickness of the transfer metal material layer 2a after drying is preferably 0.06 mm or more and 0.08 mm or less.

The term “drying” here means that the solvent contained in the original paste-like transfer metal material layer 2a evaporates, and the transfer metal material layer 2a is solidified to such an extent that the paste does not adhere to the hand even if it is touched by the hand. Means the state of being

In the transfer base material 6, it is preferable that a cushioning material 7 made of, for example, silicone rubber is placed so as to be laminated on the upper main surface of the film base material 6a in FIG. It is not limited to this mode. This cushioning material 7 has the same plane shape and size as the film-shaped substrate 6a, and the thickness thereof is the hole diameter in the plan view of the large-diameter through hole 3b (when the large-diameter through hole 3b is rectangular, the maximum is defined as above. It is preferable that the size is 1/3 or more and 1/2 or less. As described above, the transfer substrate 6 having the dried transfer metal material layer 2a is formed.

After the transfer metal material layer 2a is dried, the formed transfer substrate 6 is set so as to face the upper main surface 1f (the other main surface) of the ceramic green sheet 1. Specifically, the transfer base material 6 is aligned such that the transfer metal material layer 2a faces (overlaps in plan view) the large-diameter through hole 3b in the upper main surface 1f of the ceramic green sheet 1. To be done. The transfer substrate 6 in this state is laminated on the ceramic green sheet 1.

Next, in this state, the pressure F is applied from above to below the transfer base material 6 and from below to above the film material 4. At this time, particularly, the transfer base material 6 and the ceramic green sheet 1 are pressed so that the transfer metal material layer 2a comes into contact with the inside of the large-diameter through hole 3b. As a result, the transfer metal material layer 2a on the lower main surface of the film-shaped substrate 6a is transferred into the large-diameter through hole 3b.

In this pressure treatment, a hydraulic press machine is used in which the ceramic green sheet 1 on which the transfer base material 6 is laminated is sealed in advance by a vacuum pack, and water pressure is applied to the sealed product to apply pressure. It was As a condition of the pressure treatment, the laminated body of the ceramic green sheet 1 and the transfer base material 6 sealed by a vacuum pack is put in warm water whose liquid temperature is heated to 80° C. or higher and 90° C. or lower. It In that state, a pressing pressure of 30 MPa or more and 40 MPa or less (pressure F in FIG. 6) is applied for a time of 20 minutes or more and 30 minutes or less.

For example, if the pressure F is less than 5 MPa, the transfer metal material layer 2a on the film-shaped substrate 6a is not transferred at all into the large-diameter through hole 3b. When the pressure F is 10 MPa or more and less than 20 MPa, a part of the transfer metal material layer 2a remains on the film-shaped substrate 6a after the transfer. By setting the pressure F to 30 MPa or more and 40 MPa or less, the transfer metal material layer 2a formed on the transfer base material 6 is entirely transferred into the large-diameter through-hole 3b without being left on the film-shaped base material 6a. You can

Referring to FIG. 7, transfer base material 6 is separated from ceramic green sheet 1 when large-diameter through hole 3b is filled with transfer metal material layer 2a. The transfer metal material layer 2a is preferably filled in the entire large-diameter through hole 3b, but may be filled so as to form a space (void) not filled in the uppermost portion in the large-diameter through hole 3b. Good.

By mounting the cushioning material 7 on the film-shaped substrate 6a, the cushioning material 7 is deformed in the pressing step of FIG. This deformation facilitates transfer of the transfer metal material layer 2a into the large-diameter through hole 3b. The thickness of the cushioning material 7 affects the quality of the transferred state of the transfer metal material layer 2a into the large-diameter through hole 3b. Specifically, for example, in the case of transferring favorably to a region having a diameter of 0.5 mm or more and 1 mm or less such as the large-diameter through hole 3b (so that the transfer metal material layer 2a does not remain on the transfer base material 6), It is more preferable to use the cushioning material 7 having a thickness of 1/3 or more and 1/2 or less of the hole diameter.

Referring to FIG. 8, after the transferring step of FIG. 6, the large-diameter through holes 3b to which the transfer metal material layer 2a is transferred and the small-diameter through holes 3s in which the small-diameter metal material layer 5 is formed are covered. , (Basically larger in plane area than each of the large diameter through hole 3b and the small diameter through hole 3s), the wiring pattern 2b is formed. This wiring pattern 2b will eventually become the extra-hole metal material layer.

The wiring pattern 2b covers the through holes 3 (the transfer metal material layer 2a and the small-diameter metal material layer 5 filling the through holes 3) of the ceramic green sheet 1 by a known screen printing method, for example, a paste-like metal material in a thin film form. Is formed by being supplied to. The paste-like metal material supplied here is, for example, a paste-like metal material in which silver powder is dispersed in a solvent.

The transfer metal material layer 2a and the wiring pattern 2b that covers the transfer metal material layer 2a form a heat dissipation via pattern 2 in a region that planarly overlaps the large-diameter through hole 3b.

With reference to FIG. 9, after the heat dissipation via pattern 2 is formed, the film-like material 4 attached to the lower main surface 1b of the ceramic green sheet 1 is peeled off from the main surface 1b of the ceramic green sheet 1. Be done.

With reference to FIG. 10, the steps of FIGS. 2 to 9, that is, the step of preparing the ceramic green sheet 1 and forming the through holes 3 (3b, 3s), the step of attaching the film-like material 4, the transfer substrate The steps of facing 6 and the step of transferring the transfer metal material layer 2a are repeated. As a result, a plurality of ceramic green sheets 1 having the same mode as in FIG. 9, that is, the transfer metal material layer 2a and the like are transferred into the large-diameter through holes 3b and the heat dissipation via patterns 2 and the like are formed, are prepared.

Basically, as shown in FIG. 9, it is preferable that the wiring pattern 2b is formed on the upper main surface 1f of the ceramic green sheet 1 so as to cover the large-diameter through holes 3b and the like (that is, the lower main surface 1b). It is not necessary to form the wiring pattern 2b). However, as shown in FIG. 10, in the ceramic green sheet 1 to be finally laminated as the lowermost layer, the large-diameter through holes 3b and the like are covered from both upper and lower sides, that is, the main surface 1f and the main surface 1b. It is preferable that the wiring pattern 2b is formed on both sides. Basically, any ceramic green sheet 1 has a through hole 3, a transfer metal material layer 2a, a wiring pattern 2b, a small-diameter metal material layer 5, etc. of the same size (so as to overlap each other) at the same position in plan view. It is formed.

Next, each of the formed ceramic green sheets 1 is superposed and laminated. At this time, the small-diameter metal material layer 5, the transfer metal material layer 2a, the wiring pattern 2b, and the like of the respective ceramic green sheets 1 are aligned so as to overlap each other.

With the plurality of ceramic green sheets 1 laminated in this manner, for example, by using a hydraulic press in the same manner as in the step of FIG. 6 described above, the uppermost main surface 1f of the laminated ceramic green sheets 1 is downward from above. The pressure F is applied from above to below the uppermost main surface 1b of the laminated ceramic green sheets 1. The conditions of the pressurizing step at this time are the same as the conditions of the pressurizing step in the step of FIG. 6 (that is, a press pressure of 30 MPa or more and 40 MPa or less is applied for 20 minutes or more and 30 minutes or less).

Referring to FIG. 11, the wiring pattern 2b of each of the plurality of ceramic green sheets 1 laminated with each other by the above-mentioned pressure F is transferred to the transfer metal material layer of the ceramic green sheet 1 directly above. It becomes a mode of contacting with 2a. Similarly, by the above-mentioned pressurization, the wiring patterns 2b of the plurality of ceramic green sheets 1 laminated to each other come into contact with the small-diameter metal material layer 5 of the ceramic green sheet 1 laminated immediately thereover. .. As a result, the plurality of transfer metal material layers 2a and the wiring patterns 2b that are stacked are integrated. Similarly, the plurality of stacked small-diameter metal material layers 5 and the wiring pattern 2b are also integrated.

With reference to FIG. 12, the laminated and thermocompression-bonded ceramic green sheet 1 is cut into an arbitrary shape and then sintered.

The sintering process is performed in the atmosphere. The sintering temperature and the sintering time are set so that the ceramic sintered body after sintering has a desired shape. Here, the sintering temperature is 900° C. or lower, and the sintering time is 1 hour or more and 5 hours or less. With the stacked ceramic green sheets 1 shown in FIG. 11 placed in a firing furnace, the ceramic green sheets 1, the transfer metal material layer 2a, the wiring pattern 2b, and the small diameter metal material layer 5 are simultaneously sintered. .. By this sintering, the ceramic green sheet 1 is shrunk to form a single ceramic substrate 11 in which they are integrated. The transfer metal material layer 2a becomes an in-hole metal material layer 12a by sintering, the wiring pattern 2b becomes an out-hole metal material layer 12b by sintering, and the small diameter metal material layer 5 becomes a small diameter via 15. In the same way that the in-hole metal material layer 12a and the out-hole metal material layer 12b are in close contact with each other to form the integrated heat dissipation via 12, the out-of-hole metal material layer 12b and the small diameter via 15 are in close contact with each other and integrated. Configure the wiring area.

As described above, the mounting substrate 10 according to the present embodiment is completed. That is, the mounting substrate 10 of FIG. 12 is basically the same as the mounting substrate 10 of FIG. 1, but from the viewpoint of emphasizing that the ceramic substrate 11 is formed by stacking the ceramic green sheets 1, The boundary is shown by a solid line.

As described above, in the present embodiment, after the plurality of ceramic green sheets 1 in which the transfer metal material layer 2a is transferred into the large-diameter through hole 3b is formed, these are stacked, pressed and integrated. Before the heating, the film-shaped material 4 attached to the lower main surface 1b of each ceramic green sheet 1 is peeled off from the ceramic green sheet 1. Here, the film-like material 4 attached to the lower main surface 1b of the ceramic green sheet 1 for the purpose of stably supplying the transfer metal material layer 2a into the large-diameter through hole 3b as described above will be described in detail. To do.

The film-shaped material 4 suppresses the metal material layers 2a and 5 from falling off when the metal material layers 2a and 5 are supplied into the through-hole 3, and the finished shape of the heat dissipation via 12 finally formed (in plan view). Is a factor that influences the diameter.

Table 1 below has a plurality of circular through holes 3 each having a rectangular shape with a length of 200 mm and a width of 200 mm in a plan view and various diameters within a range of 0.15 mm or more and 1.0 mm or less in a plan view. The result of having performed the test by changing the thickness of the film-shaped material 4 of this Embodiment formed by the hole making machine variously is shown. That is, Table 1 shows a known screen in the through hole 3 in a state in which the film-shaped material 4 of the present embodiment is attached to the lower main surface 1b of each of the plurality of ceramic green sheets 1 having different thicknesses. The filling state when the paste-like metal material is filled using the printing method is shown. The film-shaped material 4 used in the test of Table 1 has an adhesive force of 0.17 N for contacting with the ceramic green sheet 1 within a region of 25 mm width, and is formed of a polyester film. In addition, when the column of the filling state in Table 1 is "No abnormality", the warp of the ceramic green sheet 1 or the through holes 3 of the ceramic green sheet 1 in the state where the film-like material 4 is attached and the paste-like metal material is filled. It shows that the shape collapse has not occurred. The thickness of the ceramic green sheet 1 used in the test was 0.1 mm.

With reference to Table 1, when the thickness of the ceramic green sheet 1 is 0.1 mm and the thickness of the film-shaped material 4 is increased to about 0.3 mm, this is applied to the main surface 1b of the ceramic green sheet 1. When pasted, the ceramic green sheet 1 itself was largely warped, and a problem occurred when the through holes 3 were printed and filled. Specifically, due to the warpage of the ceramic green sheet 1, the ceramic green sheet 1 cannot be adsorbed on the stage base of the printing machine.

On the other hand, when the thickness of the film-shaped material 4 is reduced to 0.02 mm, the rigidity of the ceramic green sheet 1 after the film-shaped material 4 is attached becomes small. For this reason, when the ceramic green sheet 1 flows between the steps, it becomes extremely difficult to handle the ceramic green sheet 1. Specifically, the ceramic green sheet 1 was cracked at the portion where the relatively large through hole 3 (diameter in plan view of 0.6 mm or more and 1.0 mm or less) formed in the ceramic green sheet 1 was formed. Therefore, when the thickness of the ceramic green sheet 1 is 0.1 mm and the thickness of the film-shaped material 4 is reduced to 0.02 mm, the film-shaped material 4 cannot be used as a carrier film. .. From the above results, in the present embodiment, it is preferable that the thickness of the film-shaped material 4 is in the range of 0.05 mm or more and 0.12 mm or less, and the thickness of 0.05 mm or more and 0.12 mm or less is preferable. The film-like material 4 having was used.

Next, the film-like material 4 is preferably formed of polyethylene terephthalate or polyester (although partly described above), but in the present embodiment, the film-like material 4 made of polyester is used as an example. To be An adhesive material is supplied to the film-like material 4 in order to secure the adhesiveness to the ceramic green sheet 1. As the adhesive material, a commercially available material can be used as long as it can be left on the surface of the ceramic green sheet 1 immediately before sintering. In the present embodiment, as an example, the film-shaped material 4 coated with an acrylic adhesive material is used.

Next, as shown in Table 2 below, the optimum value of the adhesive force of the above-mentioned adhesive material was derived as follows, assuming the following conditions. The first condition is that the film-shaped material 4 does not separate from the ceramic green sheet 1 when the through hole 3 is filled with the metal material. The second condition is that the ceramic green sheet 1 to which the film-shaped material 4 is attached has sufficient adhesive force to be adsorbed and fixed to a stage table such as a printing machine. The third condition is that the film-shaped material 4 can be peeled from the ceramic green sheet 1 by the treatment immediately before sintering (see FIG. 11), and the through-hole 3 is filled at the time of peeling. That is, the metal material does not fall from the through hole 3.

More specifically, a plurality of circles having a thickness of 0.1 mm and having various diameters of 0.15 mm, 0.3 mm, 0.5 mm, 0.6 mm, 1.0 mm and 1.2 mm in plan view. A plurality of (here, seven) ceramic green sheets 1 each having a large number of through holes 3 formed therein were prepared. Various film-like materials 4 having different adhesive strengths were attached to the lower main surface 1b of the ceramic green sheet 1. In this state, a metallic material in which silver powder was made into a paste was filled into the plurality of through holes 3 by a known screen printing method (any of the through holes 3 has a ceramic green sheet 1 below it). Pasted). After that, the film-shaped material 4 is peeled off, and it is investigated whether or not the metal material in the through-holes 3 of each size falls off (filling out) at that time. This was examined for each of the seven samples to which the film materials 4 having different adhesive strengths were adhered, and the percentage (%) in which the metal material failed to be filled is shown. The distance between a pair of through holes 3 adjacent to each other among the many through holes 3 is about twice the diameter of the through holes 3 in a plan view, and each sample has 50 through holes 3 of each size or 100 pieces are formed.

With reference to Table 2, when the diameter of the through-hole 3 was as small as 0.15 mm, no filling failure of the metal material occurred regardless of the adhesive strength of the film-shaped material 4. On the other hand, when the diameter of the through hole 3 was 0.3 mm or more, the filling failure occurred. The higher the ratio of the diameter of the through hole 3 to the thickness of the ceramic green sheet 1, the higher the rate of filling omission. That is, in particular, if the through hole 3 becomes large, the metal material filled in the through hole 3 cannot be sufficiently supported only by the force from the inner surface of the through hole 3. The filled metallic material adhered to the film-shaped material 4 and the filling failure occurred.

When the through holes 3 having the same diameter are compared with each other, at the time of peeling the film-shaped material 4 having a large adhesive force, the filling failure occurs at a higher rate. It is considered that this is because when the film-shaped material 4 is peeled off, the metal material in the through-hole 3 that comes into contact with the film-shaped material 4 is easily pulled by the film-shaped material 4 with a stronger force.

Based on this result, the inventor of the present application has conducted diligent research, paying attention to the peeling process of the film-like material 4 which causes the filling failure, and triples the thickness of the ceramic green sheet 1 (0.1 mm). Therefore, a method of preventing the metal material in the through-hole 3 having a diameter of about 6 times from falling off when the film-shaped material 4 is peeled off was examined.

Generally, as described above, the wiring or via is formed by supplying the conductive material in the form of a paste such as powder of tungsten or silver. However, in the present embodiment, as described above, instead of supplying the paste-like metal material into the through holes 3 (large-diameter through holes 3b), the dried transfer metal material formed on the transfer substrate 6 is used. The method of providing layer 2a was used. As a result, although not shown, even if the diameter of the through hole 3 is as large as 0.6 mm, 1.0 mm and 1.2 mm, the probability of occurrence of filling failure could be reduced to zero.

Next, the operation and effect of the present embodiment will be described with reference to FIGS.
With reference to FIGS. 13A, 13B, and 13C, the mounting substrate 10 formed by the above-described manufacturing method has a plurality of ceramic greens (as shown in FIG. 1) serving as the base material of the whole. By stacking the sheets, the plurality of in-hole metal material layers 12a and the plurality of out-hole metal material layers 12b are in close contact with each other without a gap therebetween. The plurality of in-hole metal material layers 12a and the out-of-hole metal material layers 12b form an integrated heat dissipation via 12.

Note that, in FIG. 13, the illustration of the outside-pore metal material layer 12b (which is sandwiched between the pair of ceramic green sheets 1) other than the uppermost portion and the lowermost portion, which configure the heat dissipation via 12, is omitted. This also applies to the following embodiments.

The semiconductor chip 8 is mounted and mounted on the upper main surface of the out-of-hole metal material layer 12b forming the uppermost part of the heat dissipation via 12. A semiconductor element is mounted on the semiconductor chip 8.

The heat dissipation via 12 formed according to the present embodiment is formed on one main surface of the mounting substrate 10, for example, from the lowermost surface (outer hole metal material layer 12b) of the heat dissipation via 12 of FIG. The surface extends, for example, in a column shape to the uppermost surface (outer hole metal material layer 12b) of the heat dissipation via 12 in FIG. 13C. That is, the maximum dimension of the heat dissipation via 12 is 0.5 mm or more over the entire area from the lowermost in-hole metal material layer 12a to the uppermost in-hole metal material layer 12a. In other words, in the present embodiment (even though there is a difference in plane area between the in-hole metal material layer 12a and the out-hole metal material layer 12b), for example, the heat dissipation via 12 has a plane area that is downward in the thickness direction. It does not gradually become smaller and has a shape like a buttock (cone).

For this reason, it is possible to suppress a decrease in the heat radiation effect below the heat radiation via 12, which is assumed when the plane area below the heat radiation via 12 is smaller than above. The heat dissipation efficiency can be exhibited to the lower part as well. Therefore, as shown in FIG. 13C, from the uppermost portion of the heat dissipation via 12 on which the semiconductor chip 8 is mounted to the lowermost portion of the heat dissipation via 12 through which heat is released to the outside, the metal material layer 12a in the hole and the outside of the hole It is possible to provide the heat dissipation via 12 having a high heat dissipation property by integrally connecting the metal material layers 12b.

Further, the heat dissipation via 12 is formed by integrally connecting the in-hole metal material layer 12a and the out-hole metal material layer 12b formed in each ceramic green sheet 1. Therefore, when the heat of the uppermost part of the heat dissipation via 12 is transferred to the lowermost part, there is no part that blocks the heat transfer, so that it is possible to dissipate heat with high efficiency.

Next, with reference to FIGS. 14 to 15, an aspect of the heat dissipation via 12 of the mounting substrate 10 formed by the above manufacturing method will be described.

Referring to FIG. 14, this shows a mode in which one ceramic green sheet 1 is filled with a metal material in a plan view. Specifically, FIG. 14 has a configuration in which a metal material is filled in the large-diameter through hole 3b having a dimension of about 1 mm in a lateral plan view.

Referring to FIG. 15, the horizontal axis of this graph shows the horizontal coordinates of the portion filled with the metal material in the large-diameter through hole 3b of FIG. 14, and the vertical axis of this graph shows the large coordinate of FIG. The coordinates of the metal material filled in the radial through holes 3b in the direction intersecting the plane of the drawing, that is, in the Z direction are shown. The thickness of the ceramic green sheet 1 used in FIGS. 14 and 15 is about 0.1 mm.

In FIG. 15, an example in which the metal material in the large-diameter through hole 3b is filled by a known screen printing method as a comparative example (described as “printing method” in the figure), and the transfer substrate in the present embodiment The surface shape of the metal material in each of the examples (described as “transfer method” in the drawing) transferred by the transfer metal material layer 2a of 6 is shown. In the printing method data, the surface shape of the metal material after the paste-shaped metal material is filled by the screen printing method and dried is shown. In each of the samples of the printing method and the transfer method, the film material 4 was attached to the lower main surface 1b of the ceramic green sheet 1 before the metal material was filled.

The film-shaped material 4 was peeled off after being filled with the metallic material, but at that time, the metallic material filled by the printing method fell down from the large-diameter through hole 3b. On the other hand, the metal material filled by the transfer method did not fall off from the large-diameter through hole 3b even if the film-shaped material 4 was peeled off.

Incidentally, in the data of the transfer method, there are regions that largely project upward in the Z direction at the positions where the horizontal axis coordinates are about 0.5 mm and about 1.5 mm. The plane area of the material layer 2a is larger than the plane area of the large-diameter through hole 3b, and when the transfer metal material layer 2a is transferred, part of the transfer metal material layer 2a is Z on the inner surface of the large-diameter through hole 3b. This is because it largely protrudes upward in the direction.

The above results and the results in Table 2 show that when the large-diameter through-hole 3b having the maximum dimension exceeding 0.5 mm is filled with the metal material as in the present embodiment, the paste-like metal material is supplied. It is shown that it is preferable to transfer the dried metal material layer for transfer 2a rather than the transfer. In the present embodiment, the large-diameter through hole 3b is filled with the already-transferred transfer metal material layer 2a. Therefore, when the film-like material 4 having adhesiveness is peeled off, it is possible to reduce the possibility that the film-like material 4 is torn by the adhesive force of the film-like material 4 and falls off from the large-diameter through hole 3b.

This is for the following reason. Whether the paste-like metal material is supplied by the screen printing method or the transfer metal material layer 2a is transferred, the metal material is still dry when the film-shaped material 4 is peeled off. However, when the paste is supplied by the screen printing method, since the paste-like metal material has good fluidity, the paste easily spreads to the surface of the film-like material 4. Therefore, the surface of the film-like material 4 and the paste-like metal material come into contact with each other (even after drying), so that the metal material is likely to fall off when the film-like material 4 is peeled off. On the other hand, when the already-dried transfer metal material layer 2a is transferred and supplied, after the transfer, the transfer metal material layer 2a and the film-like material 4 therebelow do not come into contact with each other, for example, between them. There will be a slight gap of about 10 μm. For this reason, it is possible to reduce the possibility that the transfer metal material layer 2a will fall off when the film-shaped material 4 is peeled off.

In addition, in the present embodiment, the filling in the small-diameter through holes 3s is performed by the screen printing method without using the transfer process. This is because the paste-like metal material in the small-diameter through-hole 3s is less likely to fall off than in the large-diameter through-hole 3b, but is also difficult to transfer into the small-diameter through-hole 3s in the first place. That is, it is difficult for the buffer material 7 arranged on the film-shaped base material 6a in the transfer base material 6 to be deformed so as to follow the narrow width of the small diameter through hole 3s during the pressurizing step. For this reason, a screen printing method is often used when filling the small diameter through-hole 3s with a metal material.

Next, in the present embodiment, the transfer metal material layer 2a has already been dried at the time of transfer into the large-diameter through hole 3b. Therefore, even if the transfer metal material layer 2a is supplied into the large diameter through hole 3b, there is a risk that the inner surface (ceramic green sheet 1) of the large diameter through hole 3b is damaged by the solvent contained in the paste-like metal material. Can be eliminated. Therefore, the restriction of the solvent used for the paste-like metal material can be reduced, and the selection range can be expanded. Further, since the transfer metal material layer 2a is transferred into the large-diameter through-hole 3b having the maximum dimension exceeding 0.5 mm, the size of the through-hole to be filled with this is small when designing the paste-like metal material. It is also possible to eliminate the limitation in the selection range of the material of the solvent. This also increases the degree of freedom in designing the pasty metal material.

Further, in the present embodiment, the plurality of ceramic green sheets 1 to which the in-hole metal material layers 2a are transferred are pressed in a stacked state so that these in-hole metal material layers 2a are integrated. Is processed. As a result, the in-hole metal material layer 2a filled in the large-diameter through-hole 3b and the wiring pattern 2b covering the large-diameter through-hole 3b are integrated, and the in-hole metal material layer 2a and the out-hole metal material layer 2b are integrated. Are sintered in a state of being closely bonded. Therefore, it is possible to increase the density of the metal material forming the heat dissipation via 12 to be finally formed, and it is possible to further improve the heat dissipation performance of the heat dissipation via 12.

Furthermore, in the present embodiment, the through-holes 3 of the individual ceramic green sheets 1 are first filled with the in-hole metal material layer 2a, and then these are laminated and integrated. For this reason, for example, when the plurality of ceramic green sheets 1 are stacked before the through holes 3 of the ceramic green sheet 1 are not filled, and the plurality of ceramic green sheets 1 are finally filled all at once, the uneven filling state of the metal material can occur. Also, it is possible to suppress defects such as warpage of the ceramic substrate caused thereby.

In addition, in the present embodiment, the outside-hole metal material layer 12b (wiring pattern 2b) is formed so as to be sandwiched between the inside-hole metal material layers 12a (transferring metal material layer 2a). This makes it possible to compensate for the positional deviation between the in-hole metal material layers 12a (transfer metal material layer 2a) in plan view. Further, it is possible to reduce the possibility that the ceramic green sheet 1 (ceramic substrate 11) will be cracked around the large-diameter through hole 3b when the ceramic green sheet 1 shrinks in the sintering step. As described above, by forming the out-of-hole metal material layer 12b (wiring pattern 2b), the metal material layers can be integrated so as to more firmly adhere to each other, and as a result, the heat dissipation of the heat dissipation via 12 can be improved. It can be increased.

If the inner wall surface of the large-diameter through hole 3b (the hole metal material layer 12a therein) is exposed, a crack starting from this portion may occur during sintering. However, by forming the extra-hole metal material layer 12b to be slightly larger than the intra-hole metal material layer 12a in plan view, the intra-hole metal material layer 12a is completely covered by the extra-hole metal material layer 12b and is not exposed. .. Therefore, the effect of absorbing the positional deviation between the in-hole metal material layers 12a (transferring metal material layer 2a) in plan view and further suppressing cracks is further enhanced.

(Embodiment 2)
The aspects of the mounting substrate 10 and the heat dissipation via 12 formed in the present embodiment are basically the same as those of the mounting substrate 10 and the heat dissipation via 12 shown in FIGS. The description is omitted. Here, a method of manufacturing the mounting board 10 according to the present embodiment will be described with reference to FIGS.

Also in this embodiment, first, the same processing as the steps of FIGS. 2 to 5 of the first embodiment is performed. Since each of these steps is the same as that of the first embodiment, the description thereof is omitted here.

With reference to FIG. 16, after the steps of FIGS. 2 to 5 of the first embodiment, a transfer base material 6 for filling with a metal material is prepared similarly to the step of FIG. 6 of the first embodiment. It The transfer base material 6 has a film-shaped base material 6a, a cushioning material 7, a transfer metal material layer 2a, and a transfer metal material layer 2c (outside hole metal material layer). In this respect, the transfer base material 6 of the present embodiment includes only the transfer base material 6 (the film-shaped base material 6a, the cushioning material 7, and the transfer metal material layer 2a) of the first embodiment (FIG. 6). It has a different structure. That is, in the transfer substrate 6 of FIG. 16, the heat dissipation via pattern 2 has the transfer metal material layer 2a and the transfer metal material layer 2c.

The transfer metal material layer 2c (a plurality of) is formed in at least a partial region on the lower main surface of the film-shaped substrate 6a in FIG. Similar to the transfer metal material layer 2a, the transfer metal material layer 2c is formed by supplying a paste-like metal material in a thin film form by, for example, a known screen printing method. Here, the paste-like metal material supplied to form the transfer metal material layer 2c is, for example, a paste-like metal material in which silver powder is dispersed in a solvent.

The transfer metal material layer 2c finally plays the same role as the wiring pattern 2b of the first embodiment, which covers the large diameter through hole 3b (transfer metal material layer 2a) and the small diameter through hole 3s (small diameter metal material layer 5). Is formed. Therefore, in the transfer base material 6, the transfer metal material layer 2c can cover the large diameter through hole 3b (transfer metal material layer 2a) and the small diameter through hole 3s (small diameter metal material layer 5) at the time of the subsequent transfer. Is formed at the position

After the transfer metal material layer 2c is formed on the film-shaped substrate 6a, for example, at least a partial region of the large transfer metal material layer 2c in the central portion of the drawing (corresponding to the large-diameter through hole 3b at the time of subsequent transfer). Similar to the first embodiment, the transfer metal material layer 2a for filling the large-diameter through hole 3b is formed at the corresponding position.

The printing and drying conditions for forming the transfer metal material layers 2c and 2a are the same as those of the transfer metal material layer 2a of the first embodiment. The cushioning material 7 is also basically the same as that of the first embodiment. As described above, the transfer base material 6 having the dried transfer metal material layer 2a (hole metal material layer) and the dried transfer metal material layer 2c (outside hole metal material layer) is formed.

After the transfer metal material layers 2a and 2c are dried, the transfer base material 6 is formed on the upper main surface 1f (the other main surface) of the ceramic green sheet 1 as in the first embodiment (FIG. 6). Set to face each other. That is, in the transfer base material 6, a portion in which the transfer metal material layer 2a and the transfer metal material layer 2c are laminated faces the particularly large-diameter through hole 3b of the upper main surface 1f of the ceramic green sheet 1 ( It is aligned so as to overlap in a plan view). Further, in the transfer base material 6, a portion in which only the transfer metal material layer 2c is formed faces the particularly small-diameter through hole 3s (small-diameter metal material layer 5) of the main surface 1f on the upper side of the ceramic green sheet 1 ( It is aligned so as to overlap in a plan view).

In this state, pressure F is applied from above to below the transfer substrate 6 and from below to above the film-like material 4 by, for example, a hydraulic press. The pressure F applied at this time is slightly stronger than the pressure F applied in the step of FIG. 6 of the first embodiment, and is preferably 40 MPa or more and 50 MPa or less, for example.

Referring to FIG. 17, when the pressure F is applied, the transfer metal material layer 2a of the transfer substrate 6 is transferred into the large-diameter through hole 3b, and at the same time, the transferred transfer metal material layer 2a is transferred. The transfer metal material layer 2c is formed on the large-diameter through-hole 3b and the small-diameter through-hole 3s (on the upper main surface 1f) so as to cover the.

Since the subsequent steps are basically the same as the steps of FIGS. 9 to 12 of the first embodiment, the description thereof will be omitted here. Finally, by the sintering step, the transfer metal material layer 2a becomes the same as the in-hole metal material layer 12a in the first embodiment, but the transfer metal material layer 2c becomes the outside-hole metal material layer 12b in the first embodiment. Become.

The procedure of the manufacturing method of the present embodiment other than this is substantially the same as that of the first embodiment, and therefore, the same elements are denoted by the same reference numerals and the description thereof will not be repeated.

Next, the function and effect of this embodiment will be described. In the present embodiment, the following operational effects are obtained in addition to the operational effects of the first embodiment.

In the present embodiment, not only the transfer metal material layer 2a but also the transfer metal material layer 2c (outer hole metal material layer) corresponding to the wiring pattern 2b of the first embodiment is formed on the transfer base material 6. It is formed by transferring the formed dried metal material layer for transfer 2c. As a result, the ceramic green sheet 1 may be damaged (deformed or cracked) by supplying the paste-like metal material containing the solvent component to the ceramic green sheet 1 like the wiring pattern 2b of the first embodiment. Can be reduced.

Further, in the present embodiment, the transfer metal material layer 2c can be simultaneously supplied in the same step as the transfer metal material layer 2a is supplied to the ceramic green sheet 1. Therefore, the number of steps can be reduced and the cost can be reduced as compared with the first embodiment in which the transfer metal material layer 2a and the wiring pattern 2b are supplied in separate steps.

(Embodiment 3)
The aspects of the mounting substrate 10 and the heat dissipation via 12 formed in the present embodiment are basically the same as those of the mounting substrate 10 and the heat dissipation via 12 shown in FIGS. 1 and 13 of the first embodiment. Then, the explanation is omitted. Here, referring to FIG. 18 to FIG. 22 and referring to the drawings showing the manufacturing process of the first embodiment as appropriate, although there is a portion that partially overlaps with the above, the first example of the present embodiment will be described. A method of manufacturing the mounting substrate 10 will be described.

First, referring to FIGS. 2 and 3, similarly to the first embodiment, a ceramic green sheet 1 having through holes 3 (large diameter through holes 3b and small diameter through holes 3s) is prepared. Referring to FIG. 4, film-shaped material 4 (first film-shaped material) is attached to, for example, lower main surface 1b (one main surface) of ceramic green sheet 1. With reference to FIG. 5, the small-diameter through hole 3s is filled with the small-diameter metal material layer 5.

With reference to FIG. 6, a transfer substrate 6 having a dried transfer metal material layer 2a (first in-hole metal material layer) is prepared. With the transfer metal material layer 2a of the transfer base material 6 being dried, the transfer base material 6 faces the upper main surface 1f (the other main surface) of the ceramic green sheet 1. Specifically, the transfer base material 6 is faced so that the transfer metal material layer 2a faces the large-diameter through hole 3b of the upper main surface 1f of the ceramic green sheet 1.

Referring to FIG. 7, by pressing transfer base material 6 and ceramic green sheet 1, transfer metal material layer 2a is transferred into large-diameter through hole 3b. Referring to FIG. 8, after the transferring step of FIG. 6, the large-diameter through holes 3b to which the transfer metal material layer 2a is transferred and the small-diameter through holes 3s in which the small-diameter metal material layer 5 is formed are covered. , The wiring pattern 2b (outer hole metal material layer) is formed. The wiring pattern 2b is formed by supplying a paste-like metal material in a thin film shape by a known screen printing method.

Referring to FIG. 18, the ceramic green sheet shown in FIG. 2 is formed on the upper main surface 1b of the ceramic green sheet 1 on which the transfer metal material layer 2a is transferred and the wiring pattern 2b is formed as shown in FIG. Another ceramic green sheet 1 having a through hole 3 of the same size and shape formed therein is placed at a position overlapping the through hole 3 formed in 1 in a plan view. As a result, the ceramic green sheet 1 to which the transfer metal material layer 2a has been transferred and the other ceramic green sheet 1 first appearing in FIG. 18 are aligned such that their through holes 3 overlap each other. Are stacked. That is, the large diameter through hole 3b of the lower ceramic green sheet 1 and the large diameter through hole 3b of the upper ceramic green sheet 1 overlap each other, and the small diameter through hole 3s of the lower ceramic green sheet 1 and the upper ceramic The ceramic green sheets 1 are laminated so that the small diameter through holes 3s of the green sheet 1 overlap each other.

The other ceramic green sheets 1 may not be filled with the metal material in the large diameter through holes 3b and the small diameter through holes 3s at the time of stacking. Next, in a state in which the two ceramic green sheets 1 are superposed, for example, using a hydraulic press in the same manner as in the step of FIG. 6 above, the uppermost main surface 1f of the ceramic green sheets 1 of the upper layers of the laminated layers is above the main surface 1f. The pressure F is applied from below to above, and from below to above the lowermost main surface 1b of the lower layer ceramic green sheet 1 of the laminated layers. However, the pressure F at this time is weaker than the pressure F applied in the step of FIG. 10 of the first embodiment, and is preferably 0.5 MPa or more and 1 MPa or less.

In the present embodiment, as described below, the step of stacking and pressing the ceramic green sheets 1 is repeated one or more times (usually two or more times) to obtain a structure in which a plurality of ceramic green sheets 1 are stacked. The pressure F applied in the pressing step is preferably as weak as possible so that the ceramic green sheets 1 can be pressure-bonded to each other.

Referring to FIG. 19, after another ceramic green sheet 1 is stacked and pressed in FIG. 18, the second through hole metal material layer is filled in the through hole 3 of the upper ceramic green sheet 1. It

Specifically, a paste-like metal material is applied and filled into the large-diameter through-holes 3b and the small-diameter through-holes 3b of the upper layer ceramic green sheet 1 at the same time by a known screen printing method. The metal material is dried. As a result, the large-diameter through hole 3b of the upper ceramic green sheet 1 is filled with the coating metal material layer 2d (second hole metal material layer), and the transfer metal material layer 2a, the wiring pattern 2b, and the coating metal material layer 2d. And a layered structure are formed. A small-diameter metal material layer 5 filling the small-diameter through holes 3s of the upper ceramic green sheet 1 is also formed.

Referring to FIG. 20, a wiring pattern is again provided so as to cover the large-diameter through holes 3b to which the transfer metal material layer 2a is transferred and the small-diameter through holes 3s in which the small-diameter metal material layer 5 is formed in the process of FIG. 2b (extra-hole metal material layer) is formed. The wiring pattern 2b is formed by supplying a paste-like metal material in a thin film shape by a known screen printing method.

After that, on the upper main surface 1b of the upper ceramic green sheet 1, the same size and shape as in FIG. 2 is penetrated again at a position overlapping with the through hole 3 formed in the ceramic green sheet 1 shown in FIG. 2 in plan view. Another ceramic green sheet 1 in which the holes 3 are formed is placed. Then, from the upper side to the lower side of the uppermost main surface 1f of the laminated uppermost ceramic green sheet 1, and from the lower side to the upper side of the lowermost main surface 1b of the laminated lowermost ceramic green sheet 1, the pressure F Is applied. As a result, the uppermost ceramic green sheet 1 is pressure bonded onto the laminated ceramic green sheets 1. The conditions and the like of the stacking and pressing steps here are the same as the conditions and the like of the stacking and pressing steps in the process of FIG.

Referring to FIG. 21, the through hole 3 of the uppermost ceramic green sheet 1 laminated in the step of FIG. 20 is filled with the second in-hole metal material layer. The specific method is the same as filling the large-diameter through-holes 3b and the small-diameter through-holes 3s of the upper ceramic green sheet 1 with the metal material in the process of FIG. That is, the paste-like metal material is applied and filled into the large-diameter through-hole 3b and the small-diameter through-hole 3s simultaneously by a known screen printing method, and the paste-like metal material is dried. As a result, the large-diameter through-hole 3b of the upper ceramic green sheet 1 is filled with the coated metal material layer 2d (the second metal material layer in the hole), and the small-diameter through-hole 3s of the upper ceramic green sheet 1 is filled with the small-diameter metal material layer. Filled with 5.

Thereafter, the step of stacking the ceramic green sheets 1 as shown in FIGS. 18 and 20, and (after pressing this) the inside of the large-diameter through hole 3b of the ceramic green sheets 1 as shown in FIGS. 19 and 21 and The step of simultaneously filling the coating metal material layer 2d and the small diameter metal material layer 5 into the small diameter through hole 3s is repeated once or more (usually twice or more). As a result, a structure having the desired number of laminated ceramic green sheets 1 is formed.

With reference to FIG. 22, the uppermost wiring is laminated on the uppermost main surface 1f of the uppermost ceramic green sheet 1 of the laminated structure of the ceramic green sheets 1 formed according to FIG. 21, that is, the uppermost wiring. The film material 4 (second film material) is attached so as to cover the pattern 2b. As a result, the uppermost wiring pattern 2b is protected by the film material 4. This film-shaped material 4 is basically the same as the film-shaped material 4 attached to the bottom of the laminated structure in the step of FIG.

The top and bottom of the laminated structure of the ceramic green sheet 1 formed in FIG. 22 are reversed, and the film-shaped material 4 (first film-shaped material) attached in the step of FIG. 4 is peeled off. Then, a wiring pattern 2b is formed on the main surface 1b of the ceramic green sheet 1 exposed by peeling the film-shaped material 4 so as to cover the small-diameter metal material layer 5 and the transfer metal material layer 2a. Similar to the above, the wiring pattern 2b is formed by supplying a paste-like metal material by a screen printing method.

Thereafter, for example, similarly to the step of FIG. 10, the pressure F shown in the figure is applied to the laminated structure of the plurality of ceramic green sheets 1. As a result, the wiring patterns 2b of the plurality of ceramic green sheets 1 stacked on each other come into contact with the transfer metal material layer 2a or the coated metal material layer 2d of the ceramic green sheets 1 stacked directly above or below the wiring patterns 2b. Becomes Similarly, by the above-mentioned pressurization, the wiring patterns 2b of the plurality of ceramic green sheets 1 laminated to each other come into contact with the small-diameter metal material layer 5 of the ceramic green sheet 1 laminated immediately thereover. .. As a result, the laminated transfer metal material layer 2a, the plurality of wiring patterns 2b, and the plurality of applied metal material layers 2d are integrated. Similarly, the plurality of stacked small-diameter metal material layers 5 and the wiring pattern 2b are also integrated. The pressurizing method at this time is performed using a hydraulic press machine as in the step of FIG. The conditions of the pressurizing step at this time are preferably such that a press pressure of 30 MPa or more and 40 MPa or less is applied for a time of 10 minutes or more and 20 minutes or less.

Although not shown thereafter, the (second) film-like material 4 is peeled off from the ceramic green sheet 1 after the structure as shown in FIG. 11 is formed by the above. After that, as in the process of FIG. 12, the laminated and thermocompression-bonded ceramic green sheet 1 is cut into an arbitrary shape and then sintered. The conditions of the sintering temperature and the sintering time are the same as those in the process of FIG. As a result, the ceramic green sheet 1, the transfer metal material layer 2a, the wiring pattern 2b, the coated metal material layer 2d, and the small-diameter metal material layer 5 are placed in a state where the stacked ceramic green sheets 1 are placed in the firing furnace. Simultaneously sintered. By this sintering, the ceramic green sheet 1 is contracted to become the ceramic substrate 11. The transfer metal material layer 2a and the coating metal material layer 2d are sintered to become the in-hole metal material layer 12a, the wiring pattern 2b is sintered to become the out-hole metal material layer 12b, and the small-diameter metal material layer 5 becomes the small-diameter via 15. Become. In the same way that the in-hole metal material layer 12a and the out-hole metal material layer 12b are in close contact with each other to form the integrated heat dissipation via 12, the out-of-hole metal material layer 12b and the small diameter via 15 are in close contact with each other and integrated. Configure the wiring area. As described above, the mounting substrate 10 according to the present embodiment having the same mode as that of FIG. 1 is completed.

The procedure of the manufacturing method of the first example of the present embodiment other than this is almost the same as that of the first embodiment, and therefore, the same elements are designated by the same reference numerals and description thereof will not be repeated.

Referring to FIG. 23, the manufacturing method of mounting substrate 10 according to the second example of the present embodiment basically uses the same manufacturing method as in the first example. However, here, as in the case of the second embodiment, the transfer metal material layer 2a (first hole metal material layer) and the transfer metal material layer 2a are transferred into the large-diameter through-holes 3b of the lowermost ceramic green sheet 1. The wiring pattern 2b (outer hole metal material layer) formed so as to cover the large-diameter through hole 3b is simultaneously formed by transfer. That is, both the dried lowermost transfer metal material layer 2a and the wiring pattern 2b are included in the transfer base material 6. That is, FIG. 23 shows a mode (step) after the steps shown in FIGS.

The steps after the transfer step in the present embodiment are the same as the steps shown in FIGS. 18 to 23 of the first example of the present embodiment.

The procedure of the manufacturing method of the second example of the present embodiment other than this is almost the same as that of the first embodiment, and therefore, the same elements are denoted by the same reference numerals and description thereof will not be repeated.

Next, the function and effect of this embodiment will be described. In the present embodiment, the following operational effects are obtained in addition to the operational effects of the first embodiment.

In the present embodiment, another ceramic green sheet 1 in which the metal material is not filled in the through hole 3 is laminated, and then the coated metal material is applied in the through hole 3 of the laminated ceramic green sheet 1. The layer 2d is filled. That is, at the time of supplying the coated metal material layer 2d, the ceramic green sheet 1 is already disposed immediately below the supplied through-hole 3, and the base of the dried transfer metal material layer 2a is established. For this reason, even if the applied metal material layer 2d is in the form of a paste, it is possible to reduce the possibility that the applied metal material layer 2d will fall onto the stage table of the printing machine.

In the present embodiment, only the large-diameter through holes 3b of the lowermost ceramic green sheet 1 are filled with the transfer metal material layer 2a, but the large-diameter through holes 3b of the second or more ceramic green sheets 1 are coated. It is filled with the metal material layer 2d. In this way, if the coating metal material layer 2d is supplied by using a printing method for the second layer or more, the pressure (0.5 MPa or more and 1 MPa or less) applied when the ceramic green sheets 1 are laminated as described above, for example, as described above. The pressure can be made extremely smaller than the pressure (30 MPa or more and 40 MPa or less) applied during the transfer process of the transfer metal material layer 2a.

The lowermost ceramic green sheet 1 and the uppermost ceramic green sheet 1 are completely different in the number of times they are pressed. Therefore, if the difference in the pressing history between them becomes large, for example, the dimension of the lowermost ceramic green sheet 1 is significantly different from the dimension of the uppermost ceramic green sheet 1, and even if both are laminated, the metal in the hole is laminated. The positions of the material layers and the like in plan view may not be aligned. However, as in the present embodiment, when the second and subsequent metal material layers are filled, no transfer is used and a large pressure is not applied, so that the pressure between the ceramic green sheets 1 of the lowermost layer and the uppermost layer is increased. The difference in history can be reduced. Therefore, when the layers are stacked, the positions of the metal material layers in the holes and the like in plan view can be aligned.

Also in this embodiment, similarly to the first embodiment, the laminated structure of the heat dissipation via is formed while the through hole 3 of each ceramic green sheet 1 is filled with the in-hole metal material layer 2a one by one. .. For this reason, for example, when the plurality of ceramic green sheets 1 are stacked before the through holes 3 of the ceramic green sheet 1 are not filled, and the plurality of ceramic green sheets 1 are finally filled all at once, the uneven filling state of the metal material can occur. Also, it is possible to suppress defects such as warpage of the ceramic substrate caused thereby.

Further, when the method of individually preparing the ceramic green sheets 1 one by one and finally stacking them all together at a time as in Embodiment 1 is used, as many film green materials 4 as the number of the ceramic green sheets 1 are used. The step of peeling occurs. However, in the present embodiment, since only two film-shaped materials 4 can be attached, the step of peeling the film-shaped material 4 is performed only twice. Therefore, in the present embodiment, the number of times of peeling the film-shaped material 4, which is a step in which the filled metal material is highly likely to drop off, can be reduced as compared with the first embodiment. Therefore, the risk of the metallic material falling off can be further reduced.

In the present embodiment, the film-like material 4 is attached so as to cover the wiring pattern 2b on the large-diameter through hole 3b formed by the screen printing method, but when the film-shaped material 4 is peeled off, the wiring pattern 2b falls off. There is no possibility to do it. The metal material layer filled in the large-diameter through-hole 3b by the printing method may only fall off when the film-shaped material 4 is peeled off. If the film-shaped material 4 is attached onto the wiring pattern 2b or the like as the extra-hole metal material layer, the metal material layer filled in the large-diameter through hole 3b on the wiring pattern 2b will be the film-shaped material 4. It has a role of reducing the possibility of falling off during peeling (protecting the metal material layer filled in the large-diameter through hole 3b).

Also in this embodiment, as in the second example (FIG. 23), the lowermost transfer metal material layer 2a and the wiring pattern 2b are simultaneously formed by one transfer base material 6 (see FIG. 16). For example, similar to the second embodiment, the effect of reducing the steps and suppressing the damage of the ceramic green sheet 1 can be obtained.

(Embodiment 4)
First, as the configuration of the mounting board of the present embodiment, particularly the configuration of the heat dissipation member formed on the mounting board will be described with reference to FIG.

Referring to FIG. 24, mounting substrate 20 of the present exemplary embodiment is similar to mounting substrate 10 of the first to third exemplary embodiments, and a plurality (seven in FIG. 24) of ceramic green sheets are laminated on each other. This is a configuration having the ceramic substrate 11 integrated by pressurization. A large diameter through hole 3b (through hole) is formed in each of the plurality of ceramic green sheets, and an in-hole metal material layer 12a having a maximum dimension in plan view of 0.5 mm or more is formed in the large diameter through hole 3b. It is filled. Further, on the upper main surface 1f of the ceramic substrate 11, for example, a pattern of the metal material layer 12b outside the hole is formed so as to cover the metal material layer 12a inside the hole. Further, the plurality of in-hole metal material layers 12a and the out-of-hole metal material layers 12b are brought into close contact with each other to be integrated with each other, thereby forming the heat dissipation via 12 as an integrated heat dissipation member of the ceramic substrate 11. Further, the heat dissipation via 12 extends in a columnar shape in the vertical direction of FIG. 24 from the lower main surface 1b of the ceramic substrate 11 to the upper main surface 1f without the plane area of the heat dissipation via 12 changing remarkably. Are continuously formed. Regarding the above, the mounting substrate 20 of FIG. 24 is basically the same as the mounting substrate 10 of FIG.

However, in FIG. 24, the uppermost outside metal material layer 12b of the heat dissipation via 12 is not disposed on the main surface 1f as the uppermost surface of the ceramic substrate 11 of the mounting substrate 20, but is lower than that. It is located in the (lower) position. That is, in the ceramic substrate 11 of FIG. 24, the outermost metal material layer 12b of the uppermost portion of the heat dissipation via 12 is arranged on the upper main surface of the uppermost ceramic green sheet of the plurality of ceramic green sheets before firing. Instead, it is placed on the upper main surface of the ceramic green sheet one layer below. As a result, the mounting substrate 20 of the present embodiment has the above-mentioned aspect. Although the large-diameter through hole 3b formed in the ceramic green sheet of the uppermost layer before firing is formed right above the heat dissipation via 12, the large-diameter through hole 3b is filled with the in-hole metal material layer 12a. It has not been. Therefore, the out-of-hole metal material layer 12b on the upper main surface of the ceramic green sheet laminated as a layer one layer below the uppermost layer is exposed, and this is the uppermost portion of the heat dissipation via 12.

In the above points, the mounting substrate 20 is different from the mounting substrate 10 of the first embodiment in which the heat dissipation via 12 has a configuration in which it extends continuously in the thickness direction of the ceramic substrate 11 from the uppermost layer to the lowermost layer of the ceramic substrate 11. ing. However, other points are basically the same as the configuration of mounting substrate 10 of the first embodiment, and therefore, the same elements are denoted by the same reference numerals and description thereof will not be repeated.

Next, with reference to FIG. 25 to FIG. 37 and some drawings that partially overlap with the above, referring to the drawings showing the manufacturing process of the first embodiment as appropriate, the mounting substrate 20 according to the present embodiment. The manufacturing method will be described.

First, referring to FIGS. 2 and 3, similarly to the first embodiment, a ceramic green sheet 1 having through holes 3 (large diameter through holes 3b and small diameter through holes 3s) is prepared.

Referring to FIG. 25, a small-diameter metal material layer 5 is filled in the small-diameter through holes 3s by supplying a paste-like metal material in a thin film form by using the screen printing method as in the step of FIG. .. In FIG. 25, the film material 4 is not attached to the lower main surface 1b of the ceramic green sheet 1 as in FIG. 4, for example. However, in the process of FIG. The film material 4 may be attached to the lower main surface 1b of the green sheet 1.

Referring to FIG. 26, similar to the process of FIG. 8, the wiring pattern 2b is formed so as to cover the small-diameter metal material layer 5 by supplying a paste-like metal material in a thin film shape by, for example, a known screen printing method. It is formed.

Referring to FIG. 27, the film-shaped material 4 (the first main surface) on the upper main surface 1f (the other main surface) of the ceramic green sheet 1 is covered so as to cover the wiring pattern 2b formed by the process of FIG. A film material) is attached. Here, as in the first embodiment, a polyester film having a thickness of 0.05 mm or more and 0.12 mm or less and an adhesive force of 0.08 N or more and 0.27 N or less (within a 25 mm width region). Material 4 is used.

Thereafter, as shown in FIG. 27, a pressure F is applied to the film-shaped material 4 in the thickness direction of FIG.

With reference to FIG. 28, as a result, the film-shaped material 4 becomes a tritch with the lower main surface 1b on the lower main surface 1b (one main surface) side in the large-diameter through hole 3b. By extending in the left-right direction of FIG. 27 along this, the large-diameter through hole 3b is deformed so as to be closed. Due to this deformation, the film-shaped material 4 adheres to the inner side surface of the large-diameter through hole 3b while following the extending direction of the inner side surface (side surface and bottom surface). Here, a sufficient pressure F may be applied to the film-like material 4 so that the large-diameter through-hole 3b is sufficiently adhered to the inner surface of the large-diameter through hole 3b so as not to create a gap. preferable. In addition, after FIG. 28 (up to FIG. 34), the top and bottom of the ceramic green sheet 1 are turned upside down with respect to the steps before FIG.

Referring to FIG. 29, in the large-diameter through-hole 3b, the film-shaped material 4 that covers the large-diameter through-hole 3b by extending in the left-right direction along the lower main surface 1b is covered so as to cover the lower part. Wiring pattern 2b is formed on main surface 1b on the side. The wiring pattern 2b here is formed by supplying a paste-like metal material in a thin film form by, for example, a known screen printing method as in the other steps described above. The wiring pattern 2b is formed to have a larger area in plan view than the large-diameter through hole 3b. The formed wiring pattern 2b becomes a wiring pattern 2b as an extra-hole metal material layer by being sufficiently dried.

Referring to FIG. 30, as shown in FIG. 29, the film-like material 4 is attached in the large-diameter through hole 3b, and on the lower main surface 1b of the ceramic green sheet 1 on which the wiring pattern 2b is formed, Another ceramic green sheet 1 having a through hole 3 of the same size and shape is placed at a position overlapping with the through hole 3 formed in the ceramic green sheet 1 shown in FIG. 2 in plan view. As a result, the ceramic green sheet 1 to which the film-shaped material 4 is attached and the other ceramic green sheet 1 first appearing in FIG. 30 are aligned so that their through holes 3 are superposed on each other. Stacked. Since the stacking mode here is basically the same as the process of FIG. 18, the details are omitted.

Next, in a state in which the two ceramic green sheets 1 are superposed, for example, by using a hydraulic press in the same manner as in the step of FIG. 18 above, the upper layer in FIG. 30 (the upper layer in FIG. Similarly, the pressure F is applied from above to below the uppermost main surface 1b of the ceramic green sheet 1 and from below to above the lowermost film-like material 4 of the lower ceramic green sheet 1 laminated. Is applied. The pressure F at this time is preferably as weak as possible, and preferably 0.5 MPa or more and 1 MPa or less, for the same reason as in the step of FIG.

31, after another ceramic green sheet 1 is laminated and pressed in FIG. 30, the through hole 3 of the upper ceramic green sheet 1 is filled with the in-hole metal material layer.

Specifically, similar to the step of FIG. 19, a paste-like metal material is applied to the large-diameter through-holes 3b and the small-diameter through-holes 3b of the upper ceramic green sheet 1 at the same time by a known screen printing method. It is filled and the paste-like metal material is dried. As a result, the large-diameter through hole 3b of the upper ceramic green sheet 1 is filled with the coated metal material layer 2d (hole metal material layer), and the wiring pattern 2b and the coated metal material layer 2d are laminated to each other. It A small-diameter metal material layer 5 filling the small-diameter through holes 3s of the upper ceramic green sheet 1 is also formed.

Referring to FIG. 32 (similar to the step of FIG. 20), the large-diameter through hole 3b in which the coating metal material layer 2d is formed and the small-diameter through hole 3s in which the small diameter metal material layer 5 is formed in the step of FIG. The wiring pattern 2b (paste-like metal material supplied by a known screen printing method) is formed again so as to cover the.

Referring to FIG. 33, thereafter, through holes 3 formed in ceramic green sheet 1 shown in FIG. 2 are again formed on upper main surface 1b of upper ceramic green sheet 1 (similar to the step of FIG. 20). Another ceramic green sheet 1 having through holes 3 having the same size and shape as in FIG. 2 is placed at the overlapping position in a plan view. Then, from the upper side to the lower side of the uppermost main surface 1f of the laminated uppermost ceramic green sheet 1, and from the lower side to the upper side of the lowermost main surface 1b of the laminated lowermost ceramic green sheet 1, the pressure F Is applied. As a result, the uppermost ceramic green sheet 1 is pressure bonded onto the laminated ceramic green sheets 1. The conditions and the like of the stacking and pressing step here are the same as the conditions and the like of the stacking and pressing step in the process of FIG.

Referring to FIG. 34, the through hole 3 of the uppermost ceramic green sheet 1 laminated in the step of FIG. 33 is filled with the in-hole metal material layer. The specific method is the same as the filling method of the metal material in the step of FIG. 31 (application of a paste-like metal material by a known screen printing method). The large-diameter through hole 3b of the uppermost ceramic green sheet 1 is filled with the coated metal material layer 2d (in-hole metal material layer), and the small-diameter through hole 3s of the upper ceramic green sheet 1 is filled with the small-diameter metal material layer 5. It

Thereafter, the step of stacking the ceramic green sheets 1 as shown in FIGS. 30 and 33, and (after pressing this) the inside of the large-diameter through holes 3b of the ceramic green sheets 1 as shown in FIGS. The step of simultaneously filling the coating metal material layer 2d and the small diameter metal material layer 5 into the small diameter through hole 3s is repeated once or more (usually twice or more). As a result, a structure having the desired number of laminated ceramic green sheets 1 is formed.

After that, the film-shaped material 4 is formed on the uppermost main surface 1f of the uppermost ceramic green sheet 1 of the laminated structure of the ceramic green sheets 1 so as to cover the uppermost wiring patterns 2b. (Second film material) is attached. As a result, the uppermost wiring pattern 2b is protected by the film material 4.

With reference to FIG. 35, the top and bottom of the laminated structure of the ceramic green sheet 1 formed in FIG. 34 are inverted, and the film-shaped material 4 (first film-shaped material) attached in the step of FIG. 28 is peeled off. To be done.

Thereafter, for example, similarly to the step of FIG. 10, the pressure F shown in the figure is applied to the laminated structure of the plurality of ceramic green sheets 1. By this pressurization, the plurality of wiring patterns 2b and the coated metal material layer 2d, which are stacked on each other, are integrated with each other, as in the other embodiments described above. In addition, the plurality of stacked small-diameter metal material layers 5 and the wiring pattern 2b are also integrated. The pressurizing method at this time is performed using a hydraulic press machine as in the step of FIG. The conditions of the pressurizing step at this time are preferably such that a press pressure of 30 MPa or more and 40 MPa or less is applied for a time of 10 minutes or more and 20 minutes or less.

Referring to FIG. 36, the (second) film-shaped material 4 is peeled off from the ceramic green sheet 1 after the pressing step. Referring to FIG. 37, thereafter, similarly to the step of FIG. 12, the laminated and thermocompression-bonded ceramic green sheet 1 is cut into an arbitrary shape and then sintered. The conditions of the sintering temperature and the sintering time are the same as those in the process of FIG. By this sintering, the plurality of ceramic green sheets 1 become an integrated ceramic substrate 11, the applied metal material layer 2d becomes an in-hole metal material layer 12a by sintering, and the wiring pattern 2b becomes an out-of-hole metal material layer by sintering. 12b, and the small diameter metal material layer 5 becomes the small diameter via 15. In the same way that the in-hole metal material layer 12a and the out-hole metal material layer 12b are in close contact with each other to form the integrated heat dissipation via 12, the out-of-hole metal material layer 12b and the small diameter via 15 are in close contact with each other and integrated. Configure the wiring area. As described above, the mounting substrate 20 of this embodiment having the same mode as that of FIG. 24 is completed.

Referring to FIGS. 38(A), (B), and (C), the mounting substrate 20 formed by the above manufacturing method (as shown in FIG. 24: similar to that of the first embodiment) is By stacking the plurality of ceramic green sheets as the base material, the plurality of in-hole metal material layers 12a and the out-of-hole metal material layers 12b are in contact with each other so as to be in close contact with each other without a gap. The plurality of in-hole metal material layers 12a and the out-of-hole metal material layers 12b form an integrated heat dissipation via 12.

The difference from the first embodiment is that the outermost metal material layer 12b at the uppermost portion of the heat dissipation via 12 is not on the uppermost surface of the entire mounting substrate 20 (the uppermost main surface of the ceramic substrate 11), Is also disposed at a lower position (on the main surface above the ceramic green sheet which is one layer lower than the uppermost layer among the plurality of ceramic green sheets before firing). As a result, the region on the surface of the extra-pore metal material layer 12b has a shape as if the ceramic substrate 11 were partially recessed. This recessed region is formed because the large-diameter through hole 3b of the ceramic green sheet laminated as the uppermost layer was not filled when the ceramic substrate 11 was formed. Therefore, the semiconductor chip 8 placed (mounted) on the outside hole metal material layer 12b is mounted on the surrounding ceramic substrate 11 (formed by sintering the uppermost ceramic green sheet among the plurality of ceramic green sheets). It is arranged so as to be surrounded.

Next, the function and effect of this embodiment will be described. In the present embodiment, the following operational effects are obtained in addition to the operational effects of the first and third embodiments.

In the present embodiment, the wiring pattern 2b dried in the step of FIG. 29 is formed so as to cover the portion of the film-shaped material 4 that closes the large-diameter through hole 3b along the main surface 1b of the ceramic green sheet 1. It After that, another ceramic green sheet 1 is laminated thereon so that the large-diameter through holes 3b are overlapped with each other, and a paste-shaped coating metal material layer 2d is supplied into the large-diameter through holes 3b.

In other words, the large-diameter through hole 3b of the ceramic green sheet 1 laminated on top is in a state in which the dried wiring pattern 2b is arranged directly below the large-sized through hole 3b, and in this state, the coated metal material layer 2d is supplied. Therefore, the lower side of the large-diameter through hole 3b is supported by the base of the dried and strong wiring pattern 2b. Therefore, even if the applied metal material layer 2d is in the form of paste, it is possible to reduce the possibility that it will fall off on the stage table of the printing machine or the like.

Further, the film-shaped material 4 is attached so as to extend in the direction along the main surface 1b in the large-diameter through hole 3b and close the same. Therefore, it is possible to suppress the occurrence of a problem such that the wiring pattern 2b cannot be formed on the large-diameter through hole 3b because it is not filled.

In Embodiments 3 and 4, since the paste-like metal material is applied in the large-diameter through-hole 3b in this way, the inner surface (ceramic green sheet 1) of the large-diameter through-hole 3b has the paste-like metal material. It is preferable to reduce the possibility of being damaged by the solvent contained in. Therefore, in the third and fourth embodiments, as compared with the example of transferring the dried metal material as in the first embodiment, a paste-like metal containing a solvent made of a material that is less likely to damage the ceramic green sheet 1. Preferably a material is used.

Further, according to the manufacturing method of the present embodiment, since the semiconductor chip 8 is arranged so as to be surrounded by the surrounding ceramic substrate 11 as described above, the semiconductor chip 8 should be arranged at a position where it is easily protected from the surroundings. You can

In addition, also in the present embodiment, the paste-like metal material is filled in the same way as the large-diameter through holes 3b of the second or more layers in the third embodiment. As a result, it is not necessary to apply a large pressure (as in the transfer step) at the time of filling the metal material, and it is possible to suppress the occurrence of the difference in size and shape due to the difference in the pressing history of the ceramic green sheet 1 between the uppermost layer and the lowermost layer. You can

Further, in the present embodiment as well as in the third embodiment, the number of peeling of the film-shaped material 4 can be reduced as compared with the first embodiment, so that the risk of the metallic material falling off can be further reduced.

(Embodiment 5)
The preferable dimension of the heat dissipation via 12 formed by the manufacturing method of each of the above-described embodiments was verified by actual measurement. The results will be described with reference to FIGS. 39 to 41 and Table 3.

Referring to FIGS. 39(A), (B), and (C), here, as an example, the manufacturing method shown in the first embodiment is used, and FIGS. 1 and 15(A), (B), and (C) are used. The mounting substrate 10 having the heat dissipation vias 12 having the same form as in (1) was prepared. The land conductor pattern 9 is arranged on the uppermost surface of the heat dissipation via 12, and the land conductor pattern 9 covers the entire heat dissipation via 12.

Here, as an example, the heat dissipation via 12 is prepared such that the in-hole metal material layer 12a and the out-hole metal material layer 12b are rectangular (rectangular or square) in a plan view. In this actual measurement, a plurality of heat dissipation vias 12 (mounting substrate 10) having different sizes in plan view of the in-hole metal material layer 12a and the out-hole metal material layer 12b were prepared.

The overall thickness of the ceramic substrate 11 after sintering was 0.6 mm, and the ceramic substrate 11 had a substantially square planar shape with a width of 5 mm and a length of 5 mm. In Table 3 below, the horizontal dimension of the in-hole metal material layer 12a of each mounting substrate 10 in plan view is Lx (see FIG. 39), and the vertical dimension is Ly (see FIG. 39). The dimensions of the sample of the heat dissipation via 12 are shown. Further, Table 3 shows the flatness of the surface of the heat dissipation via 12 of each sample on which the semiconductor chip 8 is mounted (the surface of the uppermost outside hole metal material layer 12b). Here, the flatness indicates the difference between the maximum value and the minimum value of the position coordinates (z coordinate) of the surface in the thickness direction of the ceramic substrate 11.

It was confirmed that, for each of the heat dissipation vias 12 in Table 3, by applying the manufacturing method of the first embodiment, the in-hole metal material layer 12a is formed without dropping off. Note that, as shown in Table 3, the flatness deteriorates as the planar dimension of the heat dissipation via 12 increases. However, since this is a natural result, the flatness was divided by the standard value in order to determine whether or not the flatness is acceptable after canceling out the increase in flatness affected by the sample size. It is necessary to obtain the relative value and use the relative value for judgment.

As shown in Table 3, some of the heat dissipation vias 12 of the sample do not have a square planar shape. Therefore, referring to FIG. 40, when the planar shape of the heat dissipation via 12 is not square, the square root of the area of the large-diameter through hole 3b filled with the in-hole metal material layer 12a is calculated, and the heat dissipation vias of all the samples have a square shape. And the maximum dimension of the in-hole metal material layer 12a in a plan view was determined. Note that, here, since all are considered to be square shapes, all the maximum dimensions are the length of one side of the (imaginary) square shape shown in FIG.

Referring to FIG. 41, the horizontal axis of the graph represents the maximum dimension of the in-hole metal material layer 12a in plan view (including the dimension of one side when assuming a square shape), and the vertical axis represents the surface of each sample. Shows the relative value of the flatness of. The number of samples plotted in FIG. 41 and the number of samples shown in Table 3 do not match, but this is because some (typical) values of the values plotted in FIG. This is because

Basically, from the viewpoint of ensuring the heat dissipation of the heat dissipation vias to the semiconductor chip 8 and the like, the relative value of the surface flatness is required to be 1 or less. From FIG. 41, for that purpose, the length of one side as the maximum dimension of the intra-hole metal material layer 12a (assumed to be a square) is required to be 2.5 mm or less. Therefore, if the results shown in Table 3 and FIG. 41 are combined, the heat dissipation via 12 of the present embodiment formed by filling the large-diameter through hole 3b has one side as the maximum dimension of the in-hole metal material layer 12a. It can be said that the length needs to be 0.5 mm or more and 2.5 mm or less. Therefore the area in plan view of the portion of the hole in the metal material layer 12a becomes 0.25 mm ² or more 6.25 mm ² or less.

The disclosure contents of the respective embodiments described above can be appropriately combined even if not explicitly stated above as long as there is no technical contradiction.

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

1 ceramic green sheet, 1b lower main surface, 1f upper main surface, 2 heat dissipation via pattern, 2a, 2c transfer metal material layer, 2b wiring pattern, 2d coated metal material layer, 3b large diameter through hole, 3s small diameter Through hole, 4 film material, 5 small-diameter metal material layer, 6 transfer base material, 6a film base material, 7 cushioning material, 8 semiconductor chip, 9 land conductor pattern, 10, 20 mounting substrate, 11 ceramic substrate, 12 heat dissipation via, 12a metal material layer inside hole, 12b metal material layer outside hole, 15 small diameter via.

Claims (9)

A ceramic substrate that is sintered in a state in which a plurality of ceramic green sheets laminated on each other are integrated,
An in-hole metal material layer filling a through hole formed in each of the plurality of ceramic green sheets, and an out-of-hole metal material formed in each of the plurality of ceramic green sheets so as to cover the in-hole metal material layer. A mounting board comprising a heat dissipation member formed by being integrated with a layer,
The heat dissipation member extends in a columnar shape in the entire mounting substrate,
The maximum dimension of the metal material layer in the hole in plan view is 0.5 mm or more,
A method of manufacturing a mounting board, wherein the size, position and shape of the plurality of extra-hole metal material layers in plan view are equal,
A ceramic sheet having through holes formed therein, and a step of preparing a transfer substrate having a dried intra-hole metal material layer,
Attaching a film-like material to one of the main surfaces of the ceramic sheet;
A step of facing the transfer substrate so that the in-hole metal material layer faces the other main surface on the side opposite to the one main surface of the ceramic sheet;
A step of transferring the in-hole metal material layer into the through-hole by pressing the transfer base material and the ceramic sheet,
A step of preparing a plurality of the ceramic sheets to which the in-hole metal material layer is transferred in the through hole by repeating the step of preparing the ceramic sheet, the step of attaching, the step of facing and the step of transferring,
The heat dissipation of the in-hole metal material layer is achieved by stacking, pressing and unifying the plurality of ceramic sheets so that the in-hole metal material layers of the plurality of ceramic sheets overlap each other. And a step of forming a member,
After the transferring step and before the laminating, pressing and integrating steps, a step of peeling the film-like material attached to the one main surface of each of the plurality of ceramic sheets from the ceramic sheet. A method for manufacturing a mounting substrate, further comprising: After the step of transferring, the method further comprises the step of forming an out-hole metal material layer so as to cover the through-hole to which the in-hole metal material layer has been transferred,
The method for manufacturing a mounting substrate according to claim 1, wherein the extra-hole metal material layer is formed by printing a paste-like metal material. Further comprising a step of forming an extra-hole metal material layer so as to cover the through-hole to which the intra-hole metal material layer has been transferred,
The dried extra-pore metal material layer is included in the transfer substrate together with the intra-pore metal material layer,
The method for manufacturing a mounting substrate according to claim 1, wherein the extra-hole metal material layer is formed by transfer at the same time when the intra-hole metal material layer is transferred in the transferring step. A ceramic substrate that is sintered in a state in which a plurality of ceramic green sheets laminated on each other are integrated,
An in-hole metal material layer filling a through hole formed in each of the plurality of ceramic green sheets, and an out-of-hole metal material formed in each of the plurality of ceramic green sheets so as to cover the in-hole metal material layer. A mounting board comprising a heat dissipation member formed by being integrated with a layer,
The heat dissipation member extends in a columnar shape in the entire mounting substrate,
The maximum dimension of the metal material layer in the hole in plan view is 0.5 mm or more,
A method of manufacturing a mounting board, wherein the size, position and shape of the plurality of extra-hole metal material layers in plan view are equal,
A step of preparing a transfer sheet having a ceramic sheet in which through holes are formed, and a dried first in-hole metal material layer;
Attaching a first film-like material to one main surface of the ceramic sheet;
A step of facing the transfer base material so that the first in-hole metal material layer faces the other main surface opposite to the one main surface of the ceramic sheet;
Pressing the transfer base material and the ceramic sheet to transfer the first in-hole metal material layer into the through-hole,
After the step of transferring, on the other main surface of the ceramic sheet, another ceramic sheet in which the through holes are formed, a step of laminating the through holes so that they overlap each other, and
After the step of stacking the ceramic sheets, a step of filling the through-holes of the stacked ceramic sheets with a second in-hole metal material layer is provided. After the transferring step, the method further comprises the step of forming an out-hole metal material layer so as to cover the through-hole to which the first in-hole metal material layer has been transferred,
The method for manufacturing a mounting substrate according to claim 4, wherein the extra-hole metal material layer is formed by printing a paste-like metal material. Further comprising a step of forming an out-hole metal material layer so as to cover the through hole to which the first in-hole metal material layer has been transferred,
The dried extra-pore metal material layer is included in the transfer substrate together with the first intra-pore metal material layer,
The method for manufacturing a mounting substrate according to claim 4, wherein the extra-hole metal material layer is formed by transfer at the same time when the first intra-hole metal material layer is transferred in the transferring step. Repeating the stacking step and the filling step one or more times;
After the repeating step, a step of attaching a second film-shaped material to the other main surface of the ceramic sheet that is finally laminated among the plurality of ceramic sheets,
A step of forming a heat dissipation member composed of the first and second in-hole metal material layers and the out-of-hole metal material layers by pressurizing and integrating a plurality of the ceramic sheets;
The method for manufacturing a mounting substrate according to claim 5, further comprising a step of peeling the first and second film-shaped materials from the ceramic sheet. A ceramic substrate that is sintered in a state in which a plurality of ceramic green sheets laminated on each other are integrated,
An in-hole metal material layer filling a through hole formed in each of the plurality of ceramic green sheets, and an out-of-hole metal material formed in each of the plurality of ceramic green sheets so as to cover the in-hole metal material layer. A mounting board comprising a heat dissipation member formed by being integrated with a layer,
The heat dissipation member extends in a columnar shape in the entire mounting substrate,
The maximum dimension of the metal material layer in the hole in plan view is 0.5 mm or more,
A method of manufacturing a mounting board, wherein the size, position and shape of the plurality of extra-hole metal material layers in plan view are equal,
A step of preparing a ceramic sheet in which a through hole is formed,
On the one main surface side of the ceramic sheet, the first film is formed on the other main surface of the ceramic sheet opposite to the one main surface so as to close the through hole along the one main surface. The step of sticking the strip-shaped material,
Forming a dried extra-hole metal material layer on the one main surface of the ceramic sheet so as to cover the portion of the first film-like material that closes the inside of the through hole;
On the one main surface of the ceramic sheet, a step of stacking the other ceramic sheet in which the through holes are formed so that the through holes are overlapped with each other,
And a step of filling the through-holes of the ceramic sheets stacked in the stacking step with an in-hole metal material layer. Repeating the stacking step and the filling step one or more times;
After the repeating step, a step of attaching a second film-shaped material to the one main surface of the ceramic sheet that is finally laminated among the plurality of ceramic sheets,
A step of forming a heat dissipation member composed of the extra-hole metal material layer and the intra-hole metal material layer by pressing and integrating the plurality of ceramic sheets;
The method for manufacturing a mounting substrate according to claim 8, further comprising a step of peeling the first and second film-shaped materials from the ceramic sheet.

Images