JP2013016894A - Solid-state imaging device and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin solid-state imaging device having high rigidity, improved accuracy, and high reliability and allowing for high-density wiring.SOLUTION: The solid-state imaging device of this invention is provided with: an insulating multilayer substrate having an aperture and including at least one layer of inner-layer metal core; a translucent member installed on one surface of the multilayer substrate so as to cover the aperture; and a solid state imaging element installed on the other surface of the multilayer substrate so as to cover the aperture. The solid-state imaging device includes regions where the inner layer metal core is exposed, at the periphery of the multilayer substrate.

Description

  The present invention relates to a solid-state imaging device and a manufacturing method thereof, and in particular, a small-sized solid-state imaging device formed using a solid-state imaging device such as a surveillance camera, a medical camera, an in-vehicle camera, an information communication terminal camera, and the like. It relates to a manufacturing method.

  In recent years, the demand for small cameras for mobile phones, in-vehicle components, etc. has been rapidly increasing. This type of small camera uses a solid-state imaging device that outputs an image input as an electrical signal by an optical system such as a lens by a solid-state imaging device. With the downsizing and higher performance of this imaging device, the use in various fields has increased, expanding the market as a video input device. In a conventional image pickup apparatus using a semiconductor image pickup device, components such as an LSI on which a lens, a semiconductor image pickup device, a driving circuit thereof, a signal processing circuit, and the like are mounted are respectively formed in a housing or a structure and combined. The mounting structure by such a combination often takes a structure in which each element is mounted on a flat printed board. However, along with the market demand for higher functionality (miniaturization, higher resolution), the miniaturization of the image sensor has progressed, and a slight misalignment becomes a problem in image quality, and improvement in mounting accuracy is desired.

  For example, in Patent Document 1, a high-precision wiring is formed using a flexible wiring board. However, in order to avoid a problem that misalignment is likely to occur when a solid-state imaging device is mounted, a flexible wiring board and a reinforcing board are used. A method has been proposed in which a multilayer substrate is used and a through hole penetrating the multilayer substrate is used as a positioning hole.

JP 2008-263550 A

The solid-state imaging device of Patent Document 1 has a problem in that sufficient accuracy cannot be obtained because the through hole is formed by machining. Further, since one side is a reinforcing plate, the parts cannot be arranged, and the function is limited.
In recent years, in the fields of surveillance cameras, medical cameras, in-vehicle cameras, cameras for information communication terminals, etc., there is an increasing demand for higher functionality of cameras. Miniaturization and high density are required.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solid-state imaging device that can cope with further miniaturization and higher density.

  In view of this, the solid-state imaging device of the present invention has an insulating laminated substrate having an opening and including at least one inner metal core, and a transparent substrate installed on one surface of the laminated substrate so as to close the opening. An optical member; and a solid-state imaging device installed so as to close the opening on the other surface of the multilayer substrate, and including a region where the inner metal core is exposed at a peripheral portion of the multilayer substrate. It is characterized by.

  The present invention is also the above-described solid-state imaging device, comprising an insulating laminated substrate having an opening and including at least one inner metal core, and closing the opening on one surface of the laminated substrate. A translucent member installed in such a manner, and a solid-state imaging device installed so as to close the opening on the other surface of the multilayer substrate, and the inner layer metal core is disposed on a peripheral portion of the multilayer substrate. It includes a plurality of exposed areas.

  The present invention is the solid-state imaging device, wherein the plurality of regions include a reference hole provided in the multilayer substrate, and the inner metal core is exposed at a periphery of the reference hole, It includes one in which a solid-state imaging device and a translucent member are disposed on both surfaces of a multilayer substrate.

  Further, the present invention is the above-described solid-state imaging device, wherein the translucent member includes an optical lens, and the optical lens and the solid-state imaging element with respect to the multilayer substrate on the basis of the plurality of regions. Including those that can be aligned from the front and back.

  Moreover, this invention is the said solid-state imaging device, Comprising: The said translucent member contains an optical filter.

  The present invention includes the solid-state imaging device, wherein the inner metal core is a metal plate that is formed on the entire surface while avoiding a through hole of the multilayer substrate.

  In addition, the present invention includes the solid-state imaging device, wherein a ground portion of a wiring pattern of the multilayer substrate is electrically connected to the metal plate.

  Moreover, this invention is said solid-state imaging device, Comprising: The said laminated substrate contains what was comprised with the laminated body of the resin base material and the wiring pattern.

  Moreover, this invention is said solid-state imaging device, Comprising: The said multilayer substrate contains what was comprised by the laminated body of the ceramic base material and the wiring pattern.

  In addition, a method for manufacturing a solid-state imaging device according to the present invention includes a step of forming an insulating multilayer substrate having an opening, including at least one inner metal core, and having an opening therethrough. A step of cutting the outer shape of the multilayer substrate so as to protrude the metal core, a step of mounting a solid-state imaging device so as to close the opening of the multilayer substrate, and a translucency so as to close the opening of the multilayer substrate And a step of mounting the member.

  Moreover, this invention is a manufacturing method of the said solid-state imaging device, Comprising: The process of forming the said laminated substrate includes the process of forming a reference | standard hole so that the said inner-layer metal core may protrude in a periphery.

  The present invention is also a method for manufacturing the solid-state imaging device, wherein the step of forming the laminated substrate includes forming a metal plate to form an inner metal core, and forming a resin substrate including a wiring layer. And a step of attaching the inner metal core to the resin substrate.

  The present invention is also a method of manufacturing the solid-state imaging device, wherein the step of forming the multilayer substrate includes a step of forming a metal plate to form an inner metal core, and a step of forming a ceramic multilayer green sheet. And a step of adhering the inner metal core to the ceramic laminated green sheet.

According to the present invention, since the internal metal core is exposed at the peripheral edge, alignment is easy with the internal metal core as a reference. In particular, by using this internal metal core for positioning the laminated substrate and the lens housing in which the optical lens is integrated, the solid-state imaging device and the optical lens can be positioned with higher accuracy. In addition, the solid-state imaging device can be thinned, high-density wiring is possible, the positional accuracy can be improved, and a highly reliable solid-state imaging device can be obtained. Further, since the internal metal core is exposed from the laminated substrate, heat dissipation is facilitated, and the temperature rise of the solid-state imaging device chip can be prevented.
In addition, by using the method for manufacturing a solid-state imaging device of the present invention, it is possible to easily manufacture a solid-state imaging device with high controllability, high accuracy, and high reliability even when the thickness of the solid-state imaging device is reduced. As a result, the mobile terminal device can be thinned.

1 is an exploded perspective view of the solid-state imaging device according to the first embodiment. Sectional drawing which shows the state which removed the lens housing | casing of the solid-state imaging device of this Embodiment 1. FIG. Sectional drawing of the multilayer substrate used for the solid-state imaging device of this Embodiment 1. FIG. Top view showing the same multilayer substrate The figure which shows the manufacturing process of the multilayer substrate of the solid-state imaging device of this Embodiment 1. Process sectional drawing which shows the manufacturing method of the solid-state imaging device of this Embodiment 1. Process sectional drawing which shows the manufacturing method of the solid-state imaging device of this Embodiment 2. Process sectional drawing which shows the manufacturing method of the solid-state imaging device of this Embodiment 3. The top view which shows the modification of the laminated substrate of the solid-state imaging device of this Embodiment

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is an exploded perspective view of the solid-state imaging device according to the first embodiment. 2 is a perspective view showing a state in which the lens housing of the solid-state imaging device according to the first embodiment is removed, and FIG. 3 is a cross-sectional view of a main part of the multilayer substrate used in the solid-state imaging device according to the first embodiment. FIG. 4 is a top view showing the laminated substrate, and FIG. 5 is a diagram showing a manufacturing process of the laminated substrate.
As shown in FIG. 1, this solid-state imaging device has an opening 7, a laminated substrate 1 laminated and integrated on both surfaces of the inner metal core 2, and an opening on the inner metal core 2 side of the laminated substrate 1. 7 is provided with a translucent member (optical filter) 14 and an optical lens 15 installed so as to close the solid-state image sensor 10 and a solid-state imaging device 10 installed on the laminated substrate 1 side. And it includes four areas (exposed part 4) where the inner metal core 2 is exposed at the four corners which are the peripheral part of the multilayer substrate 1. The lens housing 16 integrated with the optical lens 15 is formed with a reference protrusion 17 constituting a lens positioning pin. The reference protrusion 17 is a reference protrusion that fits into the notch 3 serving as a reference hole. The reference protrusion 17 is a reference of the exposed portion 4 from which the inner metal core 2 is exposed. Implementation is done. Three reference protrusions 17 are provided. The presence of three enables more efficient positioning, but may be four or two.

  In the present embodiment, the laminated substrate 1 and the inner metal core 2 having substantially the same outer shape and size are laminated and bonded together. In this case, a glass epoxy resin was used as the insulating resin substrate 1 a for the laminated substrate 1, and a copper plate having a thickness of 300 μm was used for the inner metal core 2. The inner metal core 2 is provided with a cut portion 3 as a reference hole, and an exposed portion 4 of the inner metal core is formed in the periphery thereof. And the opening part 7 is opened. Further, as shown in a cross-sectional view in FIG. 3, the laminated substrate 1 has a metal wiring pattern 1b formed on a resin substrate 1a, and is installed so that the solid-state imaging device 10 is electrically connected. As shown in FIG. 1, a chip component 11 and a connector (not shown) are installed on the multilayer substrate 1 so as to be connected to the metal wiring pattern 1b. The ground portion of the metal wiring pattern 1b is electrically connected to the copper inner metal core 2. Furthermore, the solid-state image sensor 10 used at this time used what coated the black epoxy resin film (not shown) as a light shielding film on the back surface. The light shielding film may be a metal film such as a tungsten thin film formed on the back surface of the solid-state imaging device 10.

FIG. 1 is an exploded perspective view of the solid-state imaging device of the first embodiment, and is a view of the solid-state imaging device of FIG.
A laminated substrate 1 and an inner layer metal core 2 having the same outer shape are laminated and integrated, and an opening 7 is also opened in the inner layer metal core 2. As the translucent member (translucent filter) 14, glass having an infrared cut filter function was used. The lens housing 16 integrated with the optical lens 15 is formed with a reference protrusion 17 constituting a lens positioning pin. The reference protrusion 17 shown in the drawing is a protrusion serving as a reference that fits into the notch 3 serving as a reference hole.

  Further, the wiring portion of the multilayer substrate 1 constitutes a high density wiring.

FIG. 4 is a top view of the multilayer substrate of the solid-state imaging device according to the first embodiment.
A laminated substrate 1 and an inner metal core 2 having the same outer shape are laminated and integrated, and has a cut portion 3 as a reference hole.

  In addition, while mounting the solid-state image sensor 10 on the multilayer substrate 1, a chip component 11, a connector (not shown), and the like are mounted, and a mold resin is formed so as to cover the solid-state image sensor 10 and the chip component 11. Also good. By using the multilayer substrate 1 in this way, high-density wiring can be realized with high accuracy.

Next, a manufacturing process of the solid-state imaging device according to the present embodiment will be described.
FIG. 5 is a process cross-sectional view illustrating a manufacturing process of the multilayer substrate used for manufacturing the solid-state imaging device according to the first embodiment.
5A, the inner metal core 2 constituting the multilayer substrate 1 is punched to form a cut portion 3, an opening portion 7, and a recognition hole 13, and a dicing line D.D. L. Form.
Thereafter, vias are passed through the resin substrate 1a, and the metal wiring pattern 1b is formed on both surfaces. A prepreg having a thickness of 60 μm was used for the resin substrate 1a. In this case, a multi-piece metal wiring pattern 1b was formed at a time. As the resin substrate 1a, a flexible substrate such as a polyimide film may be used.

  And as shown in FIG.5 (b), the said resin base | substrate 1a was affixed on both surfaces of the inner-layer metal core 2. As shown in FIG. A copper plate having a thickness of 300 μm was used for the inner metal core. The laminated substrate 1 and the inner metal core 2 are bonded using a conductive adhesive (not shown). Therefore, the grounding portion of the wiring of the multilayer substrate 1 and the inner metal core 2 using the copper plate are electrically connected. Although not shown, an insulating film is formed on the surface of the metal wiring pattern 1b that is not desired to be grounded on the inner metal core 2 side. An exposed portion 4 of the inner metal core is secured around the cut portion 3.

In this way, after the laminated substrate 1 and the inner metal core 2 are laminated and integrated, the outer shape is cut into individual pieces by press cutting.
In this way, as shown in FIG. 5C, a multilayer substrate is obtained as the mounting substrate for the solid-state imaging device of the present invention, which has the exposed portion 4 of the inner metal core around the notch portion 3.

  As shown in FIG. 6A, the translucent member 14 is bonded using the multilayer substrate formed as described above. Subsequently, as illustrated in FIG. 6B, the solid-state imaging device 10 was installed on the metal wiring pattern 1 b of the multilayer substrate 1 so as to face the light transmissive member 14 and close the opening. A bump 10b was formed on an electrode (not shown) of the solid-state imaging device 10, and a conductive adhesive 10c was transferred and formed on the tip thereof. The bump 10b at this time was formed of a gold wire, and the conductive adhesive 10c was a silver paste. After the solid-state imaging device 10 was placed on the metal wiring pattern 1b using a recognition pattern (not shown) as a reference, the conductive adhesive 10c was heated and cured.

In FIG. 6B, a sealing resin 9 is injected around the solid-state imaging device 10 to reinforce the connection portion, and then heat curing is performed. Subsequently, the chip component 11 and the connector (not shown) were separately solder-connected to the metal wiring pattern 1b.
Then, if necessary, molding is performed, and each component is covered with a molding resin to be reinforced.
In this way, a structure in which the solid-state imaging device 10 and the translucent member 14 are stacked is formed as shown in FIG. Then, the lens housing 16 is attached to the structure to manufacture a solid-state imaging device.
In addition, a reference protrusion 17 is formed on the lens housing 16 on which the optical lens 15 is mounted, and is fitted by being inserted into the notch 3 serving as a reference hole. In addition, a wiring cable (not shown) was connected to a connector (not shown).
By adopting such a manufacturing method, it is possible to manufacture a solid-state imaging device that is simple, thin, highly rigid, highly accurate, highly radiant, and highly reliable.

  Moreover, in the solid-state imaging device of the present invention, the mounting strength of the solid-state imaging device and the chip component can be reinforced by covering the back surface of the solid-state imaging device chip with a mold resin.

  By having such a configuration, the inner layer metal core 2 having the same outer shape is partially projected while taking advantage of the thinness of the multilayer substrate 1, thereby ensuring alignment accuracy and heat dissipation. By forming the exposed portion 4 of the inner layer metal core, it is possible to avoid things that obstruct the reference recognition such as deviation of the laminated substrate 1 and protrusions on the end face, and ensure the shape of the copper end face with high accuracy. can do. With reference to the exposed portion 4 of the inner layer metal core, the reference protrusion 17 that is a lens positioning pin of the lens housing 16 can be accurately aligned. As a result, it is possible to increase the accuracy of alignment between the solid-state imaging device 10 on the multilayer substrate 1 and the optical lens 15 integrated with the lens housing 16.

  By mounting the chip component 11 on the surface of the multilayer substrate 1, the degree of freedom in electrical wiring design is increased. That is, the chip component 11 can be placed in the vicinity of the solid-state imaging device, and the electrical characteristics can be optimized. In addition, by mounting a connector (not shown) on the laminated substrate 1, a signal from the solid-state imaging device 10 can be taken out and connection with a portable device can be freely performed.

  Moreover, since the metal wiring pattern 1b is electrically connected to the copper inner layer metal core 2, noise suppression and electrostatic shielding can be performed, so that stability of electrical characteristics can be obtained. Furthermore, since a light-shielding film made of a metal thin film such as tungsten is applied to the back surface of the solid-state image sensor 10, it is possible to eliminate imaging signal noise due to light incident from the back surface of the solid-state image sensor 10. In particular, by electrically connecting the ground portion of the metal wiring pattern 1b to the copper inner layer metal core 2, noise suppression and electrostatic shielding can be particularly ensured.

  In addition, it is possible to prevent the components such as the solid-state imaging device 10 and the chip component 11 from falling off and firmly adhere to each other. Further, by forming a mold resin on the back surface of the solid-state image sensor 10, it is possible to suppress noise caused by transmitted light from the back surface of the solid-state image sensor 10. In order to further suppress the transmitted light from the back surface of the solid-state image sensor 10, a light shielding film may be formed on the back surface of the solid-state image sensor 10 as described above.

  As described above, according to the solid-state imaging device of the first embodiment, the laminated substrate and the inner metal core have a laminated structure with the same outer dimensions, and the solid-state imaging device and the translucent member or the optical lens are mounted. A reference hole or notch is formed, and the surface of the inner metal core is exposed on the periphery of the laminated substrate, and a translucent member can also be installed using the inner metal core as a mark. Therefore, the solid-state imaging device can be easily reduced in thickness, can be assembled with good workability, and high rigidity and high accuracy of optical axis alignment can be obtained.

  An optical member and an optical lens are mounted on the inner metal core side. The solid-state imaging device can perform positioning with respect to the multilayer substrate on the basis of a recognition pattern (not shown) formed on the multilayer substrate. The hole may not be a through hole but may be a cut.

  In the above embodiment, if an optical filter is used as the translucent member, it is possible to obtain an excellent imaging characteristic by cutting the infrared region of the incident light to the solid-state imaging device.

  Moreover, the thickness around the opening of the inner metal core on which the translucent member used in the solid-state imaging device of the present invention is installed may be thinner than the surroundings. As a result, the displacement of the translucent member can be eliminated and the spread of the adhesive for installation can be suppressed.

Needless to say, the alignment between the solid-state imaging device and the optical lens is necessary, but the alignment between the translucent member and the solid-state imaging device is also necessary.
The reason for this will be described.
The light emitted from the optical lens is designed to be condensed toward the solid-state imaging device, and the light is emitted from the exit pupil position accurately. For this reason, the size of the optical filter constituted by the translucent member 14 is required to have a size obtained by adding an adhesive portion to the opening of the plate-like member. In addition, the filter has a limitation in that the work size (plate material before division) is uniformly formed in the vapor deposition apparatus, and the work size is about 70 mm square. When the workpiece size is changed to a product, the cost is determined by dicing and dividing with a diamond blade or the like, that is, the number of workpieces taken from the workpiece size. Therefore, the cost can be reduced by minimizing the size including the adhesion area. From the above viewpoints, it is desirable to use a small filter in order to realize thinning and cost reduction. Therefore, as described above, the positional accuracy of the translucent member is also required to reliably cover the effective range of the light beam. .

Further, as described above, a light-shielding film may be formed on the back surface of the solid-state imaging device chip used in the solid-state imaging device. As a result, in the case of a thin solid-state imaging device, noise is generated due to light transmission from the back surface. Can be avoided.
This light-shielding film may be a metal film formed on the back surface of the solid-state imaging device. With this configuration, light from the back surface can be shielded more reliably with a thin shape.
The light shielding film may be a light shielding resin film formed on the back surface of the solid-state imaging device. With this configuration, light from the back surface can be shielded easily and reliably.

In the above embodiment, the wiring portion of the multilayer substrate and the inner layer metal core 2 are cut and formed with the opening 7 prior to bonding, but the wiring portion of the multilayer substrate and the inner layer metal core 2 are bonded together. Then, the opening 7 may be formed. At this time, by cutting with a laser or the like, the edge of the laminated substrate can be formed in a round shape, generation of dust can be prevented, and contamination of the imaging region can be prevented.
Moreover, in the said embodiment, although the four area | regions (exposed part 4) which the inner-layer metal core 2 exposes were formed in the four corners which are the peripheral parts of the laminated substrate 1, two or more are shown as a modification in FIG. If it is.

(Embodiment 2)
Next, a second embodiment of the present invention will be described.
As shown in FIG. 7, a shield member 30 is provided.
As shown in the cross-sectional view of FIG. 7, this solid-state imaging device further has a heat dissipation property by providing a shield member 30 that connects one end to the mounting substrate 100 and connects the other end to the surface of the solid-state imaging device 10. As well as improving the ground connection. Here, the solid-state imaging device 10 is connected to the wiring pattern on the mounting substrate 100 via the solder balls 18. Then, it is fixed by screws 19.

(Embodiment 3)
Next, a third embodiment of the present invention will be described.
In Embodiment 3 of the present invention, a method for forming a laminated substrate using a semi-green sheet will be described.
In this embodiment, as shown in FIGS. 8A to 8C, the step of forming the laminated substrate 1 is performed by forming a metal plate to form an inner metal core having a notch and an opening. By laminating and firing ceramic green sheets on the inner metal core, it becomes possible to form a laminated substrate having a notch with high dimensional accuracy.
That is, as shown in FIG. 8A, the inner metal core 2 is formed through a pressing process.
And according to this notch, a ceramic green sheet and a conductor layer are laminated | stacked alternately by screen printing sequentially, and a laminated body is obtained.
After that, as shown in FIG. 8B, the laminate is formed by sandwiching the inner metal core between the ceramic laminated green sheets.
Finally, as shown in FIG. Divide into individual regions along L.

  In this way, a notch with high dimensional accuracy can be formed, and the mounting accuracy can be increased. When a resin substrate is used, there is a problem that burrs are easily generated during cutting. However, by using a ceramic green sheet, a highly accurate laminated substrate can be easily formed.

  As described above, the solid-state imaging device and the manufacturing method thereof according to the present invention can reduce the thickness of the solid-state imaging device and can improve accuracy and reliability. Application to is useful.

DESCRIPTION OF SYMBOLS 1 Laminated substrate 1a Resin base | substrate 1b Metal wiring pattern 2 Inner layer metal core
3 Cut section (reference hole)
4 Exposed part of inner metal core
7 opening
9 Sealing resin 10 Solid-state imaging device (chip)
10b Bump 10c Conductive adhesive 11 Chip part 13 Recognition hole 14 Translucent member 15 Optical lens 16 Lens housing 17 Reference projection 18 Solder ball 19 Screw 30 Shield member 100 Mounting substrate

Claims (12)

An insulating laminated substrate having an opening and including at least one inner metal core;
A translucent member installed so as to block the opening on one surface of the multilayer substrate;
A solid-state imaging device installed so as to close the opening on the other surface of the multilayer substrate;
A solid-state imaging device including a plurality of regions in which the inner metal core is exposed at a peripheral portion of the multilayer substrate. The solid-state imaging device according to claim 1,
The plurality of regions include a reference hole provided in the laminated substrate,
The solid-state imaging device in which the inner metal core is exposed at the periphery of the reference hole, and the solid-state imaging element and the translucent member are disposed on both surfaces of the laminated substrate. The solid-state imaging device according to claim 1 or 2,
The translucent member includes an optical lens,
A solid-state imaging device configured such that the optical lens and the solid-state imaging device can be aligned from the front and back with respect to the multilayer substrate with the plurality of regions as a reference. The solid-state imaging device according to any one of claims 1 to 3,
The translucent member is a solid-state imaging device including an optical filter. The solid-state imaging device according to any one of claims 1 to 4,
The solid-state imaging device, wherein the inner metal core is a metal plate formed on the entire surface while avoiding a through hole of the multilayer substrate. The solid-state imaging device according to claim 5,
A solid-state imaging device in which a ground portion of a wiring pattern of the multilayer substrate is electrically connected to the metal plate. The solid-state imaging device according to any one of claims 1 to 6,
The multilayer substrate is a solid-state imaging device configured by a laminate of a resin base material and a wiring pattern. The solid-state imaging device according to any one of claims 1 to 6,
The multilayer substrate is a solid-state imaging device configured by a laminate of a ceramic base material and a wiring pattern. Forming an insulating laminated substrate having an opening, including at least one inner metal core, and having an opening therethrough;
Cutting the outer shape of the laminated substrate so that the inner metal core protrudes in part;
Mounting a solid-state imaging device so as to close the opening of the multilayer substrate;
And a step of mounting a translucent member so as to close the opening of the multilayer substrate. It is a manufacturing method of the solid-state imaging device according to claim 9,
The step of forming the laminated substrate includes a step of forming a reference hole so that the inner metal core protrudes at the periphery. It is a manufacturing method of the solid-state imaging device according to claim 10,
The step of forming the laminated substrate includes:
Forming a metal plate to form an inner metal core;
Forming a resin substrate provided with a wiring layer;
A method of manufacturing a solid-state imaging device including a step of attaching the inner metal core to the resin substrate. It is a manufacturing method of the solid-state imaging device according to claim 10,
The step of forming the laminated substrate includes:
Forming a metal plate to form an inner metal core;
Forming a ceramic laminated green sheet;
And a step of adhering the inner layer metal core to the ceramic laminated green sheet.