JP3527766B2 - Manufacturing method of laminated circuit board and laminated circuit board - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminated circuit board having a cavity and an electronic component arranged in the cavity of the laminated circuit board is covered with a resin coating member filled in the cavity. The present invention relates to the laminated circuit board.

[0002]

2. Description of the Related Art A conventional laminated circuit board is composed of a laminated ceramic substrate 1 and electronic components 9 mounted on the surface thereof, as shown in FIG. Further, the laminated ceramic substrate 1 is formed on the insulating layers 1a to 1e, the internal wiring 3 arranged between the insulating layers 1a to 1e, the via hole conductor 4 for connecting the internal wirings 3 and the like, and further formed on the surface thereof. It consisted of surface wiring 6.

Generally, the laminated ceramic substrate 1 has a green sheet multi-layer system in which a plurality of green sheets on which a conductor film to be the internal wiring 3 and a conductor to be the via-hole conductor 4 are formed are laminated and pressure-bonded and fired. Each green sheet becomes insulating layers 1a to 1e after firing.

Further, a ceramic paste to be the insulating layers 1a to 1e and a conductive paste to be a connecting portion corresponding to the internal wiring 3 and the via-hole conductor 4 are sequentially printed and laminated in a predetermined shape by a screen printing method, and then fired. There was a printing multi-layer system to do.

Further, the inventors of the present invention have solved the problems such as the restriction on the shape of the via-hole conductor 4 and the positioning at the time of stacking the green sheets, which have been problems in the green sheet multilayer system, and the problems in the printing multilayer system. The increase in the number of laminated layers, the distortion of the laminated surface due to the pattern of the internal wiring 3, and the deterioration in accuracy of the conductor film that becomes the internal wiring 3 are eliminated, and highly accurate positioning is not required, and the surface of the insulating film is flat. Then, as a method of manufacturing a multilayer ceramic substrate having a via-hole conductor 4 with an arbitrary shape, high precision, and easy formation, a ceramic slip material containing a photocurable monomer is applied to the surface of a work substrate by a doctor blade method or the like. Then, the applied insulating film is selectively exposed / developed to form a penetrating recess which becomes the via-hole conductor 4, and a conductor which becomes the via-hole conductor 4 is formed in this penetrating recess. While filling, a conductor film to be the internal wiring 3 is formed on the insulating film, further, an insulating film of the next layer is formed, a penetrating recess is formed, filling of the conductor and printing of the conductive film are sequentially repeated. A method for manufacturing a laminated circuit board in which a laminated body is integrally fired has been proposed (Japanese Patent Application No. 5-101312, etc.). In addition, the insulating film has insulating layers 1a to 1a after firing.
e, the conductor becomes the via-hole conductor 4, and the conductor film becomes the internal wiring 3.

Although a method of forming the surface wiring 6 is not described in detail, a conductor film to be the surface wiring 6 is formed on the laminated body before firing, and the insulating film, the conductor and the conductor film are integrally fired. At the same time, it was fired, or the surface wiring 6 was formed by firing on the surface of the fired laminate.

[0007] Actually, when it is used as the laminated circuit board 10, the electronic component 9 is mounted on the surface wiring 6.

[0008]

However, an IC chip, a transistor, a chip-shaped resistor, a chip capacitor, etc. are often mounted on the electronic component 9 mounted on the laminated ceramic substrate 1, but the laminated circuit substrate 10 The most obstacles to the reduction in height were IC chips and transistors.

In consideration of the height reduction of the laminated circuit board 10 having such a structure, structurally, the technique of the multi-layer package is used to form a cavity in a part of the laminated ceramic substrate 1. The problem can be solved by accommodating and arranging the tallest electronic component 9. Electronic component 9
It is not possible to store all of the above, and just storing a part of them can make a large contribution to the reduction in height.

When such a laminated circuit board 10 is considered as a multi-layer package laminating technique, that is, a green sheet multi-layer, the manufacturing method includes a green sheet laminating step, and the alignment between the green sheets is performed. It is extremely difficult, and when a via hole with a large diameter is formed to reduce the conductor resistance of the via hole conductor for connecting internal wiring, fill the through hole with a conductor that will become the via hole conductor. Even if an attempt is made, there is a problem that the conductor cannot be stably held in the through hole. In particular, a laminated circuit board is required to arbitrarily change the shape (diameter) of the via-hole conductor because the wiring for the power supply voltage and the wiring for the ground potential necessary for circuit operation are arranged inside the laminated circuit board. Therefore, it is conceivable to drill through-holes with a multi-punching system, but when trying to increase the number of holes or obtain multiple types of hole diameter, it is necessary to replace the cutting edge, which lacks practicability and reduces manufacturing costs. Will be up.

Structurally, when the electronic component arranged in the cavity is an IC bare chip, an external impact,
It is necessary to take measures to protect the IC bare chip from moisture and the like. In a multi-layer package, after placing an IC bare chip on a substrate having a cavity, in order to completely seal the cavity,
A ceramic or metal lid was covered.

That is, when the sealing of the electronic component placed in the cavity with the lid is applied to the laminated circuit board, the area around the cavity where the lid is placed is secured. This imposes great restrictions on the surface wiring pattern of the monolithic ceramic substrate, making it difficult to increase the density of the surface wiring.

Further, when the electronic component 2 shown in FIG. 5 is covered with a covering member such as resin, the covering member starts to flow, and it is difficult to perform sufficient and reliable covering. When the surface wiring 6 is formed, it becomes a great obstacle in designing the pattern, such as the electronic component cannot be mounted.

The present invention has been devised in view of the above problems, and an object thereof is a method of manufacturing a laminated ceramic substrate used for a laminated circuit board, in which a cavity for housing an electronic component is an insulating layer. A laminated ceramic substrate that can be simultaneously formed in the steps of forming a film, a conductor to be a via-hole conductor, and a conductor film to be an internal wiring, can arbitrarily form the shapes of the via-hole conductor and the cavity, and is extremely easy to manufacture as a whole. The present invention provides a method for manufacturing the same.

Further, in a laminated circuit board in which electronic parts are arranged in a cavity formed of the laminated ceramic board formed by the above-mentioned manufacturing method, the electronic parts can be easily and surely protected from external impact or moisture. It is intended to provide a laminated circuit board which can be protected from the above and can be reduced in height.

[0016]

The first invention of the present invention is as follows:
Stacking a plurality of insulating films and a conductive film serving as an internal wiring pattern connected via a via-hole conductor, and forming a storage opening serving as a cavity for storing electronic parts in a predetermined insulating film on the front surface side, The electronic component is placed in the cavity of the laminated ceramic substrate obtained by integrally firing the laminated body formed by forming the filling opening to be the hole on the bottom surface of the cavity, and the solder filled in the hole is used. A method for manufacturing a laminated circuit board, comprising: connecting the electronic component to the internal wiring pattern, wherein forming the laminated body comprises:
(1) a step of applying a ceramic slip material containing a photocurable monomer to form an insulating film, and (2) selectively exposing and developing the insulating film to form a through hole at a position to be a via-hole conductor. And (3) filling the through holes for via-hole conductors of the insulating film with a conductive paste to form a conductor to be a via-hole conductor, (4) forming a conductive paste on the surface of the insulating film. A step of printing to form a conductor film to be an internal wiring, (5) selectively exposing and developing the insulating film, and at the position where the cavity is formed, the accommodation opening and the hole portion on the bottom surface of the cavity. Forming a filling opening at which a part of the internal wiring pattern is exposed at a position where is formed, and at least steps (1), (2) and (3) are sequentially repeated, and The hole Filled with solder for bonding an electronic component, and is characterized in that bonding the electronic component to the internal wiring pattern through solder.

A second invention is a laminated circuit board which is formed by the manufacturing method according to the first invention and further has an electronic component covered with a resin coating member filled in the cavity.

The through-hole penetrates the insulating film, but the lower opening of the through-hole is closed by the conductor film or conductor already formed before forming the insulating film.
Since it has a “concave” shape as a whole, in order to distinguish it from the through-hole of the green sheet multilayer system, in the manufacturing method of the present invention, it is referred to as “through-concave” and the accommodation opening is referred to as “accommodation-opening depression”.

[0019]

According to the manufacturing method of the first invention, the insulating film is formed by applying the ceramic slip material regardless of the laminated state such as the pattern shape of the internal wiring and the number of laminated layers. In step (2), the surface of the insulating film becomes uniform, and in the step (2), the storage opening concave portion that becomes a cavity is formed in the insulating film by the exposure and development processes. The dimension of the storage opening concave portion is highly accurate, and any shape can be easily formed.

Furthermore, since the laminated body which becomes the laminated ceramic substrate is formed by selectively repeating the steps (1) to (4) sequentially, the positioning and laminating of the green sheets is not required at all as in the conventional case. A laminated ceramic substrate can be easily formed.

Therefore, the shape of the cavity and the shape of the via-hole conductor can be easily achieved. In particular, by making the shape of the via-hole conductor a predetermined shape, the power supply wiring and the ground wiring in the circuit of the laminated circuit board can be obtained. A via-hole conductor suitable for connecting between the internal wiring of can be easily achieved, and the cavity shape can be formed according to the shape of the electronic component arranged in the cavity.
It is possible to minimize the restrictions on the patterns of internal wiring and surface wiring.

Further, according to the laminated circuit board of the second invention, some or all of the electronic components, which have been obstacles to the height reduction of the laminated circuit board, are placed in the cavity, and all or a part of the electronic components. Therefore, it is possible to reduce the height of the entire laminated circuit board by the amount of the stored height direction.

Further, in order to protect the electronic parts by disposing a resin covering member in the cavity in which the electronic parts are arranged, a lid is placed around the cavity like a multi-layer package. Area is not required and the resin coating member does not flow out of the cavity, so there are no surface wiring pattern restrictions, and the resin coating member sufficiently protects electronic components. can do.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a laminated circuit board 10 according to the present invention.

In FIG. 1, 1 is a laminated ceramic substrate and 2 is an electronic component.

The laminated ceramic substrate 1 has insulating layers 1a-1a.
e, the internal wiring 3 arranged between the respective layers of the insulating layers 1a to 1e, the surface wiring 6, and the insulating layers 1a to 1b on the front surface side of one main surface.
It is composed of a cavity 5 which is formed so as to penetrate through the thickness direction and a via-hole conductor 4 which connects between the wirings 3 and 6. The electronic component arranged in the cavity 5 is covered and protected by the resin covering member 7.

On the surface of the insulating layer 1a, in addition to the surface wiring 6, a thick film resistor film is formed, and other electronic parts are mounted.

The insulating layers 1a-1e are, for example, 850-10.
Glass that enables firing at relatively low temperatures around 50 ° C
The surface insulating layers 1a to 1e made of a ceramic material have a thickness of 40 to 120 μm. Then, the internal wiring 3 and the insulating layers 1a to 1e are provided between the respective layers of the plurality of insulating layers 1a to 1e.
A via-hole conductor 4 and a cavity 5 penetrating in the thickness direction are arranged respectively.

The internal wiring 3 is disposed between the insulating layers 1a to 1e, and is made of a gold-based, silver-based, or copper-based metal material such as a silver-based conductor. The thickness of these internal wiring 3 is 8
It is about 15 μm.

The surface wiring 6 is formed on the surface of the insulating layer 1a, and is made of a gold-based, silver-based, or copper-based metal material, for example, a copper-based conductor. The surface wiring 6 forms a predetermined wiring substantially on the surface, and is connected to the internal wiring 3 via the via-hole conductor 4. In particular, the copper-based surface wiring 6 is an important conductor material for increasing the density because migration or the like does not occur. In the case of a copper-based conductor, it is necessary to perform baking in a reducing atmosphere or a neutral atmosphere, but a silver-based conductor may be used in order to perform baking processing simultaneously when firing the laminated ceramic substrate 1. Absent.

The via-hole conductor 7 is made of a gold-based, silver-based, or copper-based metal material, for example, a silver-based conductor, connects the internal wirings 3 and also the surface wiring 7 formed on the insulating layer 1a.
To connect the internal wiring 3 with the insulating layers 1a to 1d.
Is formed to penetrate the thickness of the.

The cavity 5 is the laminated ceramic substrate 1
Is formed in a concave shape on the surface side. That is, it is formed by stacking openings that penetrate the thickness of the insulating layers 1a and 1b on the front surface side. Therefore, the bottom surface 5c of the cavity 5
Substantially exposes part of the insulating layer 1c.
On the bottom surface 5c, a part of the internal wiring 3 arranged between the insulating layers 1b and 1c is exposed as the connection electrode pad 3a of the electronic component 2. In addition, the planar shape of the cavity 5 is substantially a shape in which the electronic component 2 can be stored,
For example, it has a rectangular shape, a circular shape, or a shape similar to that of the electronic component 2, and its depth is preferably such that the electronic component 2 can be completely housed as shown in FIG. A part may protrude from the laminated ceramic substrate 1a. In addition, a plurality of electronic components 2 are provided in this cavity 5.
May be placed.

Examples of the electronic component 2 include an IC bare chip, a chip resistor, a chip capacitor, and other chip components, as well as an IC, a transistor, and an oscillation component already housed in a container. The electronic component to be housed / arranged in the cavity 5 is the most bulky electronic component that determines the height direction of the entire laminated circuit board 10. Such an electronic component 2 has a connection electrode pad 3a on the bottom surface of the cavity 5.
Are electrically connected to each other via solder and a bonding thin wire.

It is desirable that all of the electronic components 2 be housed in the cavity 5. However, in consideration of the thickness of the laminated ceramic substrate 1 and the densification of the internal wirings 3, all of them are necessarily arranged. You don't have to. Even if the electronic component 2 is placed in the cavity 5 and the upper portion of the electronic component 2 seems to project from the surface of the multilayer ceramic substrate 1, the height of the multilayer circuit substrate 10 is increased by the amount of the stored electronic component 2. The size in the depth direction is reduced, and as a result, the height of the laminated circuit board 10 as a whole is greatly reduced.

The resin coating member 7 contains epoxy resin, acrylic resin or the like as a main component, and further contains a filler such as fused silica. This resin covering member 7
Covers the electronic component 2 arranged in the cavity 5, is supplied so as to cover at least the connecting portion, and is cured by heat.

In the figure, the resin coating member 7 completely covers the electronic component 2 arranged in the cavity 5 and has the same height as the surface of the laminated ceramic substrate 1. This is the electronic component 2 placed in the cavity 5,
This is the case where the IC bare chip is used, and the IC bare chip is completely covered, and the joint portion between the IC bare chip and the connection electrode pad 3a (the solder joint portion in the flip chip method, the bonding thin wire in the wire bonding method) is complete. Is covered. In addition to the IC bare chip, for example, when a container or an electronic component 2 already coated with a resin is used, or when the electronic component 2 partially projects from the cavity 5, a joint portion between the electronic component 2 and the connection electrode pad 3a It suffices to dispose the resin-made covering member 7 that includes the above and can sufficiently obtain the bonding strength of the electronic component 2.

As described above, in the above-mentioned laminated circuit board 10 which is the second invention of the present invention, since the electronic component 2 is arranged and housed in the cavity 5 formed in the laminated ceramic substrate 1, it is housed. The height of the entire laminated circuit board can be reduced accordingly.

Further, since the resin-made covering member 7 for covering the electronic component 2 arranged in the cavity 5 is simply supplied to the cavity 5 recessed from the surface of the laminated ceramic substrate 1 and cured, The resin coating member 7 does not flow over the cavity 5 so that the electronic component 2 can be reliably coated, and in particular, there is no pattern restriction of the surface wiring 6 in the cavity 5 and it corresponds to high density of the surface wiring 6. it can.

Next, a method of manufacturing the above-mentioned laminated ceramic substrate 1 according to the first invention will be described with reference to FIGS. 2 (a) to 2 (O).

First, as shown in FIG. 2A, in the step (1), an insulating film 10e to be the insulating layer 1e is formed on a work substrate 15 made of heat resistant resin, glass, ceramic or the like.

The insulating film 10e is obtained by homogeneously kneading a ceramic powder, a glass material, a photocurable monomer, an organic binder, and an organic or aqueous solvent, and a slip material of 40 to 40.
It is formed by coating and drying so as to have a thickness of about 120 μm.

Examples of the above-mentioned ceramic powder include materials such as cristobalite, quartz, corundum (α-alumina), mullite, zirconia and cordierite.
The average particle size of the powder is preferably 1.0 to 6.0 μ.
m, and more preferably 1.5 to 4.0 μm. Two or more kinds of these ceramic materials may be mixed and used.

Particularly, the use of corundum is advantageous in terms of cost.

Here, the average particle size of the ceramic powder is 1.
The average particle size is 1.0 μm, which is set to 0 to 6.0 μm.
If it is less than the above range, it becomes difficult to homogeneously mix and slip, and the exposure light is diffusely reflected at the time of exposure described later, and sufficient exposure cannot be performed. On the other hand, if the average particle size exceeds 6.0 μm, the dense and high-strength circuit board 1 cannot be obtained.

The above-mentioned glass material is a glass frit containing a plurality of metal oxides and has a temperature of 850 to 1050 ° C.
After calcination in 1., at least one crystal of cordierite, mullite, anorthite, sergian, spinel, garnite, willemite, dolomite, petalite or a substituted derivative thereof is precipitated.

In particular, the use of a crystallized glass frit which deposits anorthite or Celsian gives a monolithic ceramic substrate 1 of higher strength, and a crystallized glass frit which deposits cordierite or mullite is used. Since the coefficient of thermal expansion after firing is low, an IC is formed as an electronic component 2 in the cavity 5 of the laminated ceramic substrate 1.
It is very effective when placing bare chips.

The most preferable glass material in consideration of the strength and the coefficient of thermal expansion of the laminated ceramic substrate 1 is B ₂ O ₃ ,
A glass frit containing SiO ₂ , Al ₂ O ₃ , ZnO, and an alkaline earth oxide. Such a glass frit has a wide vitrification range and a yield point of 600 to 800 ° C.
Since it is in the vicinity, it is suitable for low-temperature firing at about 850 to 1050 ° C., and is copper-based to be the internal wiring 3 and the via-hole conductor 4,
It is suitable for the sintering behavior of silver-based and gold-based conductive materials.

The glass material is mixed in the slip material in the form of a frit. The average particle size of this frit is 1.
It is 0 to 5.0 μm, preferably 1.5 to 3.5 μm. Here, if the average particle diameter is less than 1.0 μm, it is difficult to make slippage, and the exposure light is diffusely reflected at the time of exposure described later, and sufficient exposure cannot be performed. On the other hand, if the average particle diameter exceeds 5.0 μm, the dispersibility is impaired, and specifically, it cannot be uniformly dissolved and dispersed between the ceramic powders that are the insulating material, and the strength is greatly reduced.

The composition ratio of the above-mentioned ceramic material and glass material is such that when firing at a relatively low temperature of 850 to 1050 ° C., the ceramic material is 10 to 60 wt%, preferably 30 to 50 wt%. Is 90-40
wt%, preferably 70 to 50 wt%.

Here, if the ceramic material is less than 10 wt% and the glass material exceeds 90 wt%, the insulating layer is excessively vitreous, which is inappropriate from the viewpoint of the strength of the insulating layer. Material exceeds 60wt%,
When the glass material is less than 40 wt%, the exposure light is diffusely reflected at the time of exposure to be described later, sufficient exposure is possible, and the denseness of the insulating layer after firing is also impaired.

In addition to the above-mentioned solid components such as ceramics and glass, the constituent material of the slip material is a photocurable monomer that is lost by sintering, an organic binder,
Contains an organic solvent.

The photo-curable monomer has excellent thermal decomposability so that it can be eliminated by a baking process at a relatively low temperature and in a short time, and it is photo-polymerized by exposure after coating and drying of the slip material. A monomer having a secondary or tertiary carbon, which is capable of forming free radicals and chain-growth addition polymerization, is preferable, for example, an alkyl acrylate such as butyl acrylate having at least one polymerizable ethylene group. And their corresponding alkyl methacrylates are effective. In addition, polyethylene glycol diacrylates such as tetraethylene glycol diacrylate and methacrylates corresponding to them can be mentioned.

The photocurable monomer is added in a predetermined amount so that the insulating film 10e is cured by the exposure treatment and the portion other than the exposed portion can be easily removed by the development treatment. For example, it is 5 to 15 wt% or less with respect to the solid component (ceramic material and glass material).

The organic binder should have a good thermal decomposability like the photocurable monomer. At the same time, since it determines the viscosity of the slip, the wettability with the solid content must be emphasized.According to the study of the present inventor, a carboxyl group such as acrylic acid or methacrylic acid-based polymer and an alcoholic hydroxyl group are determined. The ethylenically unsaturated compounds provided are preferred. Addition amount is 25 based on solid content
Wt% or less is preferable.

As the solvent, in addition to the organic solvent, an aqueous solvent can be used. In this case, the photocurable monomer and the organic binder must be water-soluble, and the monomer and the binder should be used. , Hydrophilic functional groups such as carboxyl groups are added. The amount of addition is 2 to 300, preferably 5 to 100, when expressed by acid value. If the addition amount is small, the solubility in water and the dispersibility of the powder of the fixed component will be poor, and if it is large, the thermal decomposability will be poor. In consideration of the above, it is appropriately added within the above range.

The photo-curable monomer and the organic binder in any of the slip materials must have good thermal decomposability as described above.
It must be capable of thermal decomposition below 0 ° C. More preferably, it is 500 ° C. or lower.

When the thermal decomposition temperature exceeds 600 ° C., it remains in the insulating layer and is trapped as carbon, which causes the substrate to turn gray and the insulation resistance of the insulating layer to decrease. Also, it may become void and cause delamination.

Further, a sensitizer, a photoinitiator material, etc. may be added to the slip material, if necessary. For example, examples of the photoinitiator-based material include benzophenones and acyloin ester compounds.

Examples of the method of applying the above slip material include a doctor blade method (knife coating method), a roll coating method, a printing method and the like. In particular, a doctor blade method or the like is preferable because it makes it easy to flatten the surface of the insulating film after coating. The amount of the solvent added is adjusted according to the coating method to adjust the viscosity to a predetermined value.

As a drying method, a batch type drying furnace or an in-line type drying furnace is used, and the drying condition is 120 ° C.
The following is desirable. Further, since rapid drying may cause cracks on the surface, it is important to avoid rapid heating.

Then, the insulating film 10e coated with the slip material and dried is subjected to the entire surface exposure processing as required.

Next, as shown in FIG. 2B, in the step (4), the conductor film 30 to be the internal wiring 3 disposed between the insulating layer 1e and the insulating layer 1d is made of, for example, Ag-based conductive material. It is printed in a predetermined shape by screen printing using a conductive paste and dried. The above-mentioned conductive paste is gold, silver,
At least one metallic material of copper or its alloys,
For example, a silver-based powder, a low melting point glass component, an organic binder, an organic solvent, and, if necessary, the above-mentioned photo-curing monomer are homogeneously kneaded. The insulating layers 1a to 1
e is made of glass-ceramic and has a sintering temperature of 850 to
Since it is relatively low at 1050 ° C., it is necessary to consider the sintering behavior of the insulating film. As the low melting point glass component, it is important to use one having a yield point of 700 to 800 ° C. and low thermal expansion, and approximates the sintering behavior of the insulating film and the sintering behavior of the internal wiring 3 and the via-hole conductor 4. At the same time, the difference in coefficient of thermal expansion is reduced.

If necessary, the conductor film 30 printed as described above is exposed to light to be photocured. this is,
Insulating film 10d applied on the entire surface of insulating film 10e described later.
In addition, the conductive film 30 exposed from the lower opening of the through recess 40 of the insulating film 10d is also not removed when the exposure and development processes are performed to form the through recess 40. Therefore, if the developing solution removes only the insulating film that has not been exposed to light and controls its components and concentrations so as not to remove the conductor film 30, it is not necessary to use a photocurable monomer in the conductive paste, and The exposure process for the film 30 can be omitted.

Next, as shown in FIG. 2C, the step (1) is repeated to form an insulating film 10d to be the insulating layer 1d so as to completely cover the conductor film 30 formed on the insulating film 1e. It is formed by applying and drying the above slip material.

Next, as shown in FIG. 2 (d), the insulating film 10d coated with and dried with the slip material, which is the previous step of the step (2), is selectively exposed to a predetermined amount of the insulating film 10d. The through recess 4 is formed at a position, that is, a position where the via hole conductor 4 is formed.
A solubilized portion 40 ′ that becomes 0 is formed.

Specifically, since the photo-curable monomer contained in the insulating film 10d is a negative type that is photo-polymerized, a predetermined pattern such that only the solubilized portion 40 'which becomes the through-hole recess 40 is not exposed to the exposure light. The photo target having the above is placed on or close to the insulating film 10d, and low voltage, high voltage,
The exposure light of the mercury lamp system of ultra high pressure is irradiated. The exposure condition is that the exposure light of 15 to ²⁰ J / cm ² is irradiated for about 15 to 30 seconds. As a result, the photopolymerization reaction of the photocurable monomer occurs in the portion other than the portion of the insulating film 10d that becomes the via-hole conductor 4 and is photocured. The exposure device may be a general one used in so-called photolithography.

Then, as shown in FIG. 2 (e), (2)
As a post-process of the above process, the exposed insulating film 10d is subjected to a development process to remove the solubilized portion 40 ′ and form a through recess 40. As a result, a part of the conductor film 30 formed on the insulating film 10e is exposed at the lower opening of the through recess 40.

Specifically, as a developing treatment, chlorocene, 1,1,1-trichloroethane, and an alkali developing solvent are sprayed or brought into contact with the solubilized portion 40 'by, for example, a spray developing method or a paddle developing method. , Develop processing. Then, if necessary, washing and drying are performed.

Next, as shown in FIG. 2 (f), (3),
In the step (4), the insulating film 1 having the through recesses 40 is formed.
The conductor 41 serving as the via-hole conductor 4 is filled in 0d, and the conductor film 30 serving as the internal wiring 3 disposed between the insulating layer 1c and the insulating layer 1d is printed and filled or printed on the insulating film 10d. Form.

Specifically, as described with reference to FIG. 2B, screen filling is performed using an Ag-based conductive paste to print a filling or predetermined shape, followed by drying.
When a photo-curable monomer is added to the g-based conductive paste, it is cured by exposure treatment. As described above, when the conductor material forming the via-hole conductor 4 is different from the conductor material forming the internal wiring 3, the conductor film 30 and the conductor 41 are formed.
It is necessary to perform the forming step of (3) separately, that is, the step (3) and the step (4) are performed separately.

Subsequently, in the step (1), the insulating film 10c to be the insulating layer 1c is formed, and in the step (2), the insulating film 10c is formed.
The through-hole recess 40 to be the via-hole conductor 4 is formed in c by the above-described selective exposure processing and development processing, and in the step (3),
A conductive paste is printed and filled in the penetrating recesses 40 of the insulating film 10c to form the conductor 41, and in the step (4), the conductive film 30 to be the internal wiring 3 is formed on the insulating film 10d. Here, a part of the conductor film 30 which becomes the internal wiring 3 formed on the insulating film 10c is exposed from the cavity 5 and becomes the connection electrode pad 3a connected to the electronic component 2.

FIG. 2 (g) shows the laminated ceramic substrate 1 which is laminated by the above steps.

Next, as shown in FIG. 2H, the step (1) is repeated to form the insulating film 10b to be the insulating layer 1b so as to completely cover the conductor film 30 formed on the insulating film 1c. It is formed by applying and drying the above slip material.

Next, as shown in FIG. 2I, the insulating film 10b coated with and dried with the slip material, which is the previous step of the step (2), is selectively exposed. That is, a solubilized portion 40 ′ serving as the through recess 40 is formed at a predetermined position of the insulating film 10 b, that is, a position serving as the via-hole conductor 4, and a solubilized portion 50 ′ serving as the through recess 50 is formed at a position serving as the cavity 5.
The shape of the through recess 50 can be easily formed by a method similar to that of FIG. 2D described above, only by arbitrarily changing the pattern of the photo target.

Next, as shown in FIG. 2J, as a step after the step (2), the exposed insulating film 10b is developed to remove the solubilized portions 40 'and 50', and the penetration Recess 4
0, 50 are formed. Thereby, the through recesses 40, 5
A part of the conductor film 30 formed on the insulating film 10c is exposed in the lower opening 0 '. It should be noted that a part of the conductor film 30 exposed from the lower opening of the penetrating recess 50 is a part of the electronic component 2.
Of the connection electrode pad 3a.

Next, as shown in FIG. 2 (k), (3),
In the step (4), the insulating film 1 having the through recesses 40 is formed.
The conductor 41 to be the via-hole conductor 4 is filled in 0b, and the conductor film 30 to be the internal wiring 3 disposed between the insulating layer 1a and the insulating layer 1b is formed on the insulating film 10b by printing.

Next, as shown in FIG. 2 (l), an insulating film 10a to be the uppermost insulating layer 1a is formed by the step (1), and through recesses 50 and 40 (2) are formed in the insulating film 10a. )
And the conductor 41 to be the via-hole conductor 4 is formed in the penetrating recess 40 in the step (3). As a result, a laminated body that forms the basis of the circuit board 1 is formed.

Next, as shown in FIG. 2 (m), the work substrate 15 is separated, a dividing groove is formed by press molding so that the work substrate 15 can be divided according to the dimensions of the circuit board 1, and integral sintering is performed. .

Sintering consists of a binder removal process and a firing process. In the binder removal process, the insulating films 10a to 10e, the conductor film 30 that becomes the internal wiring 3, and the conductor 4 that becomes the via-hole conductor 4 are formed.
This is because the organic components contained in 1 and 2 are eliminated, and the sintering process is performed in a temperature range of, for example, 600 ° C. or lower.

In the firing process, the insulating films 10a-10e are used.
Glass component is sufficiently softened and uniformly dispersed in the grain boundaries of the ceramic powder to give the laminated ceramic substrate 1 a certain strength, and at the same time, the silver-based powder of the conductor film 30 and the conductor 41 is grain-grown to lower the Insulating layers 1a to 1 along with resistance
It is integrated with e and is performed at a peak temperature of 850 to 1050 ° C. in an oxidizing atmosphere or a neutral atmosphere.

As a result, the insulating films 10a to 10e become the insulating layers 1a to 1e, the conductor film 30 becomes the internal wiring 3, and the conductor 41 becomes the via-hole conductor 4.

When a ceramic substrate is used as the work substrate 15, it can be used as it is as a part of the laminated ceramic substrate 1. At this time, internal wiring may be formed on the work substrate 15.

Next, as shown in FIG. 2 (n), the insulating layer 1
A conductor film to be the surface wiring conductor 7 is formed by printing on the surface of a with a copper-based conductive paste, and then dried and fired.

Here, the copper-based surface wiring 7 and the via-hole conductor 4 of a silver-based conductor are joined. Therefore, in consideration of the eutectic temperature of silver and copper, a copper-based conductive paste that can be fired at a low temperature (for example, 780 ° C. or less) is screen-printed as the copper-based surface wiring 7 to prevent copper oxidation. Therefore, it is important to carry out in a reducing atmosphere or a neutral atmosphere. Then, if necessary, the plurality of insulating layers 1a to 1e,
The multilayer ceramic substrate 1 including the internal wiring 3, the via-hole conductor 4, the surface wiring 6, and the like is achieved.

Next, as shown in FIG. 2 (O), the electronic component 2 is placed in a cavity 5 having an opening on the surface of the laminated ceramic substrate 1 and a connection electrode pad 3a on the bottom surface to be connected. It is electrically joined to the electrode pad 3a. For example,
An IC bare chip having an input / output electrode pad formed on the back surface is used as the electronic component 2 and is joined to the connection electrode pad 3a in the cavity 5 via solder (flip chip joining).
To be done. Then, if necessary, this cavity 5
When the resin-made covering member 7 is supplied and heat-cured, the laminated ceramic substrate 10 shown in FIG. 1 is completed.

As described above, according to the first aspect of the present invention, the cavity 5 formed in the laminated ceramic substrate 1
Since the electronic component 2 is mounted inside, the height reduction of the entire laminated circuit board can be achieved.

In the step of forming each insulating film, the surface of the insulating film is always a uniform surface regardless of the number of stacked layers and the pattern condition of the internal wiring 3, and the surface is flattened even after firing. Therefore, even if the conductor film 30 to be the internal wiring 3 is formed, the electronic component 2 is arranged on the bottom surface of the cavity 5, and the surface wiring 6 is formed, the formation or the arrangement can be surely performed. Become.

Further, the cavity 5 is formed in each insulating film 10a.
Since it can be formed simultaneously in a part of the forming process of the via-hole conductors 4 formed in 10e to 10e (the process of forming the through recess 40), the number of steps in the manufacturing process of the laminated circuit board is not added, and it can be easily performed. Can be formed.

Also, the via-hole conductor 4 and the cavity 5
Can have any shape. For example, regarding the shape of the via-hole conductor 4, the via-hole conductor 4 connecting the internal wirings 3 related to the power supply wiring, the ground potential, etc.
Thus, the conductor resistance of the via-hole conductor 4 can be easily reduced, and the shape of the cavity 5 can be the minimum required depending on the shape of the electronic component 2 arranged in the cavity 5. It becomes extremely easy to form the side surface of the cavity 5 into a step shape, and the restriction of the internal wiring 3 and the surface wiring 6 can be greatly relaxed.

Further, conventionally, in the electronic component 2 arranged on the surface of the laminated circuit board, the wiring connected to the electronic component 2 is limited to the surface wiring, but in the present invention, the wiring connected to the electronic component 2 is limited to the surface wiring. Since the internal wiring 3 can be used, the restriction on the pattern shape of the surface wiring 6 is relaxed, and the pattern of the internal wiring 3 can be used efficiently, resulting in a higher density of the surface wiring 6. Is possible.

In the above embodiment, the internal wiring 3,
Although the via-hole conductor 4 and the surface wiring 6 are made of different conductive materials, the baking step of the surface wiring 6 is performed at the same time in the baking step of the laminated ceramic substrate 1 by using a conductive material that can be baked at least under the same conditions. It can be carried out.

The front surface wiring 6 including the input / output terminals of the laminated ceramic substrate 1 may be formed on the back surface side of the laminated ceramic substrate 1. In this case, it is necessary to form a via-hole conductor also in the insulating layer 1e located at the bottom,
In this case, even for the insulating film 10e to be the insulating layer 1e,
In addition to the step (1), the step (2) of forming a through recess to be a via-hole conductor and the step (3) of filling a through recess with a conductor are added.

Further, a cavity for accommodating electronic components may be formed on the back surface side of the laminated ceramic substrate 1.

FIG. 3 is an enlarged view of a cavity portion showing another embodiment according to the second invention of the present invention.

In this embodiment, the insulating layer 1c which is the bottom surface of the cavity 5 is thinned to, for example, about 50 μm.
The connection electrode pad 3a exposed on the bottom surface of the cavity 5 is used as the position of the internal wiring 30 between the insulating layers 1c and 1d. That is, a filling opening 51 for removing a part of the insulating layer 1c is formed in the insulating layer 1c forming the bottom surface of the cavity 5, and the connection electrode pad 3a is exposed through the filling opening 51.

With such a structure, the connection electrode pad 3a is recessed by the thickness of the insulating layer 1c on the bottom surface of the cavity 5 and is exposed from the filling opening 51, and the IC chip as the electronic component 2 is flipped. In the case of chip bonding, the recessed portion serves as a pool of solder, and a short circuit between adjacent connection electrode pads 3a due to the outflow of solder can be prevented. This is not only applied to the IC bare chip as the electronic component 2, but a lead type electronic component as the electronic component,
It can be applied to all cases where soldering is performed for surface mount type electronic parts and chip parts.

The thickness of the insulating layer 1c can be controlled by applying the slip material to form the insulating film 10c to be the insulating layer 1c in the first invention, for example, by controlling the height of the blade by the doctor blade method. It can be easily formed by the manufacturing method described above. Further, the filling opening 51 where the connection electrode pad 3a is exposed is also easily formed by the selective exposure process and the development process without adding steps when forming the through recess 40 which becomes the via-hole conductor 4 in the insulating film 10c. Can be formed. Since the insulating layer 1c is thin, the insulating layer 1c
When the reliability of the insulation resistance between the internal wirings 3 arranged above and below c is lowered, for example, the via hole conductor formed in the insulating film 10c is used as the conductor film 30 to be the internal wiring 3 formed on the insulating film 10c. 4 is formed as a land electrode around the conductor 41, and formation of the internal wiring 3 can be substantially avoided.

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Further, FIG. 4 is an enlarged view of a cavity portion showing another embodiment according to the present invention.

In the case of a transformer component or a resistance component as the electronic component 2 housed in the cavity 5, heat is generated,
It is considered that this may cause malfunction of the circuit of the entire laminated circuit board.

In this embodiment, the heat sink member 8 is arranged on the bottom surface side of the cavity 5, that is, on the insulating layers 1d and 1e. By arranging this heat sink member, even if heat is generated from the electronic component 2 housed in the cavity 5 during the circuit operation, the heat can be efficiently removed to the outside of the laminated ceramic substrate 1, so that the heat is thermally generated. Improves reliability.

In the method of forming the heat sint member 8 as described above, when forming the insulating layers 1e and 1d, the through recess 40 which becomes the via hole conductor 4 is formed, and at the same time, the heat sint member 8 is formed at the position where the heat sinc member 8 is formed. It is formed by forming a concave portion and filling the conductor 41 to be the via hole conductor 4 with the same material as the conductor 41 to be the heat sint member 8 at the same time. That is, the heat sint member 8 can be manufactured as a via-hole conductor having an extremely large shape that is not directly related to the circuit operation.

In each of the above-mentioned embodiments, the number of laminated insulating layers can be set arbitrarily, and the electronic component 2 is housed in the cavity 5 of the laminated ceramic substrate 1. Various electronic components may be mounted on the surface of the laminated ceramic substrate 1.

[0107]

As described above, according to the first aspect of the invention, the insulating film to be the insulating layer is applied with the slip material, and the selective exposure process is performed.
A conductor film which is formed by a development process and becomes a via-hole conductor is formed by filling the through recesses formed by the selective exposure process and development process, and a conductor film which becomes an internal wiring is further formed. In the method of manufacturing a laminated circuit board including the above, the cavity for housing the electronic component can be formed at the same time as a part of the above step of forming the via hole conductor, and the cavity can be easily formed.

Since the shape of the via-hole conductor and the cavity can be arbitrarily changed by the selective exposure and development processing, the shape can be arbitrarily set, and the via-hole conductor with low conductor resistance can be easily formed. Further, a cavity corresponding to the shape of the electronic component arranged in the cavity can be easily formed, and the restrictions on the patterns of internal wiring and surface wiring can be minimized. Further, since it is possible to dispose all or a part of the electronic components in the cavity, which is an obstacle to the reduction of the height of the laminated circuit board, it is possible to arrange all or a part of the electronic components in the height direction. It is possible to reduce the height of the entire laminated circuit board by an amount, and it is possible to prevent a short circuit between adjacent internal electrode patterns due to the outflow of the solder due to a hole of the solder when the electronic component is soldered.

Further, according to the laminated circuit board of the second invention, the electronic component can be protected easily and surely from the external shock and moisture.

Further, since the resin covering member can be surely arranged only in the cavity in which the electronic parts are arranged, the surface wiring pattern can be densified.
The electronic components can be sufficiently protected.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a laminated circuit board according to a second invention of the present invention.

2 (a) to (O) are cross-sectional views of respective manufacturing steps of the laminated ceramic substrate according to the first aspect of the present invention.

FIG. 3 is an enlarged cross-sectional view of a cavity portion of the laminated circuit board according to the present invention.

FIG. 4 is an enlarged sectional view of a cavity portion of the laminated circuit board according to the present invention.

FIG. 5 is a cross-sectional view of a conventional laminated circuit board.

[Explanation of symbols]

1 ... Circuit board 1a to 1e ... Insulating layer 10a to 10e ... Insulating film 2 ... Electronic parts 3 ... Internal wiring 30 ....... Conductor film that becomes internal wiring 4 ... Via-hole conductor 40 ........ Through recesses that become via hole conductors 41 ・ ・ ・ ・ ・ ・ Conductor that becomes via-hole conductor 5 ... Cavity 7 ... Resin raw protection member

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Junichi Nakamura 1-1, Yamashita-cho, Kokubun-shi, Kagoshima Prefecture Kyocera Corporation Kagoshima-Kokubun Plant (56) Reference JP-A-5-311097 (JP, A) JP-A 63-15491 (JP, A) JP-A-4-24955 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H05K 3/46

Claims (2)

(57) [Claims] 1. A storage opening in which a plurality of insulating films and a conductive film serving as an internal wiring pattern connected via via-hole conductors are laminated on each other, and a predetermined insulating film on the front surface serves as a cavity for storing electronic components. Forming the bottom of the cavity
Together to place the electronic component on the cavity of the multilayer ceramic substrate and fired integrally a laminate obtained by forming a filling opening comprising a hole in the surface, was filled in the hole half
Connect the electronic component to the internal wiring pattern via a field
A method of manufacturing a multilayer circuit board formed by the formation of the laminate, (1) a step of applying a ceramic slip material to form an insulating film containing a photocurable monomer, (2) the Selective exposure and development of insulating film
To form a through hole at a position to be a via hole conductor
And (3) a step of filling a through hole for a via hole conductor of the insulating film with a conductive paste to form a conductor to be a via hole conductor, (4) printing the conductive paste on the surface of the insulating film, and A step of forming a conductor film to be wiring,
(5) By selectively exposing and developing the insulating film,
Storage opening and cavity at the position where the cavity is formed
-At the position where the hole is formed on the bottom surface, the internal wiring pattern
A step of forming a filling opening through which a part of the core is exposed , and at least steps (1), (2) and (3) are sequentially repeated, and an electronic component is provided in the hole.
Fill the solder for joining and insert the electronic parts through the solder
A method of manufacturing a laminated circuit board, which comprises bonding to a wiring pattern . 2. A storage opening in which a plurality of insulating films and a conductive film serving as an internal wiring pattern connected via via-hole conductors are laminated on each other, and a predetermined insulating film on the front surface serves as a cavity for storing electronic components. Forming the bottom of the cavity
Together to place the electronic component on the cavity of the multilayer ceramic substrate and fired integrally a laminate obtained by forming a filling opening comprising a hole in the surface, was filled in the hole half
Connect the electronic component to the internal wiring pattern via a field
A laminated circuit board comprising : (1) a step of applying a ceramic slip material containing a photocurable monomer to form an insulating film; and (2) selectively selecting the insulating film. After exposure and development processing,
A step of forming a through hole at a position where an opening and / or a via hole conductor is formed at a position where the cavity is formed,
(3) Filling a through hole for a via hole conductor of the insulating film with a conductive paste to form a conductor to be a via hole conductor; (4) Printing the conductive paste on the surface of the insulating film to form an internal wiring. And a step of forming a conductor film, which is formed by repeating at least steps (1), (2), and (3) in sequence, and firing the laminated body to form a laminated ceramic substrate. A laminated circuit board, characterized in that an electronic component is arranged in the cavity, and the electronic component is further covered with a resin coating member with which the cavity is filled.