DE10038429C2 - Composite laminate and method of making the same - Google Patents

Description

The present invention relates to composite laminates and methods of making the same. The present inven dung relates in particular to a composite laminate consisting of glass and ceramic materials and for use in Multilayer printed circuit boards is suitable, and relates to a method for producing the same.

2. Description of the Prior Art

With the reduction in the size and weight of chip components, corresponding reductions are also possible Size and weight of printed circuit boards required to assemble the chip components. Ceramic multilayer circuit For example, boards effectively meet such a requirement because the glass-ceramic multilayer boards have one High density wiring and a reduction in the thickness and weight of the substrates themselves are facilitated.

A glass ceramic multilayer circuit board is generally formed as follows. A variety of unsintered Layers containing both glass powder and ceramic powder are provided. At each of the specific un sintered layers, an inner conductor, for example an inner electrode, is formed by, for example, printing. These unsintered layers are laminated, pressed and annealed. Finally, outer conductive films, at for example, outer electrodes.

For realizing high density wiring on an outer surface of the glass ceramic multilayer circuit board a fine conductor pattern must be formed on the surface of the substrate. The surface flatness of the Substrate can be improved.

Such an improvement in surface flatness requires the use of not just one in the outer Surface-forming unsintered layers contain finely powdered ceramic powder, but also one fine powdered glass powder contained in the other unsintered layers. The production of a fine powder However, compared with the pulverization of the ceramic powder, glass powder is difficult and causes increased manufacturing costs. Therefore, multi-layer glass ceramic circuit boards are expensive for high density wiring.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a glass-ceramic multilayer circuit board, the right is relatively inexpensive and facilitates high-density wiring, as well as a method for producing the glass casa mic multilayer circuit board to hand.

According to one aspect of the present invention, a composite laminate comprises at least one glass Tende first layer layer and at least one ceramic layer-containing second layer layer, which is in contact with it most layer layer stands, characterized in that the second layer layer has at least one main surface of the ver Bundlaminats forms, the ceramic particles are unsintered in the second layer and that in the first layer contained glass is melted and partially penetrates into the second layer, so that the ceramic particles coexist be connected.

In the composite laminate according to the invention, the first layer layer further comprises a ceramic filler.

If the composite laminate according to the invention is used as a multilayer printed circuit board, the second can Layer provided main surface can be used as a surface for an outer conductive film, the one Part of the wiring for the multilayer circuit board.

Inside the composite laminate can be an inner conductor, which is part of the wiring for the multilayer printed circuit board represents, are provided.

According to a further aspect of the invention, a method for producing a composite lamina comprises nats a first step in the production of an unsintered composite laminate which contains at least one glass comprises the first layer and at least one second layer containing ceramic particles, the second layer is in contact with the first layer, the second layer is at least one major surface of the composite laminates, and a second step of annealing the composite green laminate at a temperature that no sintering of the ceramic particles; but melting the glass causes the first layer to melt by melting the To bind glass in the first layer and part of the molten glass penetrate into the second layer leave to bond the ceramic particles together.

In the first step of the method for producing the composite laminate, the glass is in the first layer preferably pulverized and the ceramic particles in the second layer layer have grain sizes that are smaller than that of the glass powder.

In the first step, the first layer layer preferably further comprises a ceramic filler.

In the first step, the first layer layer can be provided as a layer that can be treated alone, and the second layer layer may be formed on the first layer layer. Alternatively, the first layer layer and the second layer layer is provided as the first layer and the second layer, which are each treated alone can, and the first layer and the second layer can be stacked on top of each other to form an unsintered Ver to form bundle laminate.

When applying this method to a method of manufacturing a multilayer circuit board, an outer one conductive film, which forms part of the wiring for a multilayer circuit board, on at least one through the second layer layer formed main surface.

An inner conductor, which forms part of the wiring for a multilayer printed circuit board, can be inside the unsintered one  Composite laminates are formed.

According to the invention, the surface roughness of the second layer essentially depends on the size of the layer ceramic layer contained in the second layer layer. Thus, the use of small ceramic particles improves the Surface flatness of the second layer, that is, it improves the surface flatness of the main surface of the Composite laminate, even if the unsintered layer for the first layer layer is glass powder with a relatively large par contains particle size. Accordingly, the composite laminate of the present invention can be used at a reduced cost without pulverization of the glass powder. In addition, the mechanical strength of the composite laminate can be further improved that if the first layer layer contains a ceramic filler in addition to the glass.

According to the invention, the surface roughness of the second layer essentially depends on the size of the layer ceramic layer contained in the second layer layer. Thus, the use of small ceramic particles improves the Surface flatness of the second layer, that is, it improves the surface flatness of the main surface of the Composite laminate, even if the unsintered layer for the first layer layer is glass powder with a relatively large par contains particle size. Accordingly, the composite laminate of the present invention can be used at a reduced cost without pulverization of the glass powder. When the composite laminate is used as a circuit board, an outer one can conduct the film with a fine conductor pattern can be easily formed on its main surface, resulting in wiring leads to high density on the circuit board. In addition, the mechanical strength of the composite laminate can be further improved if the first layer layer contains a ceramic filler in addition to the glass.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1A is a schematic cross-sectional view of an unsintered composite laminate according to an embodiment according to the invention SEN and Figure 1B is a schematic cross-sectional view of the composite laminate shown in Figure 1A after egg ner heat treatment..;

Fig. 2A is a schematic cross-sectional view of an unsintered composite laminate according to another embodiment OF INVENTION to the invention and Fig. 2B is a schematic cross-sectional view of the Verbundlami shown in Fig. 2A NATs after a heat treatment and

Fig. 3 is a schematic cross-sectional view of a composite laminate that has been placed on a multilayer circuit board.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Fig. 1A is a schematic cross-sectional view of a non-sintered laminate 1 according to an embodiment of the invention and Fig. 1B is a schematic cross-sectional view of a composite laminate 2 which has been formed by annealing the un-sintered laminate 1.

The unsintered laminate 1 comprises a first layer layer 4 containing glass powder and second layer layers 6 containing ceramic particles 5 . The second layer layers 6 are in contact with the first layer layer 4 . Since the second film layer 6, the first coating layer 4 sandwiched in this embodiment, the two main surfaces of the unsintered laminate 1 can be provided through the second coating layers. 6

A preferred glass material for the glass powder 3 in the first layer 4 is crystallized anorthite glass. Examples of other glass materials include borosilicate glass and crystallized cordierite glass. The particle size of the glass powder 3 is not necessarily as small as the particle size of the ceramic particles 5 and can be larger than the particle size of the ceramic particles 5 .

The first layer layer 4 is preferably provided as a layer that can be treated alone, for example as an unsintered layer containing glass powder 3 . Such an unsintered layer is formed by mixing the glass powder 3 , a dispersing medium and a binder to form a slip, by removing the bubbles in the slip and by distributing the slip using a doctor blade method to form a layer. The binder and the dispersing agent are shown as carrier medium 7 in FIGS. 1A and 1B.

Examples of useful dispersants are water, toluene, alcohols and mixtures thereof. examples for Binders are butyral resins, acrylic resins, urethane resins, vinyl acetate resins and polyvinyl alcohol. If necessary The slip may contain plasticizers, dispersants and foam suppressants. The green one Plate layer can be formed by extrusion, rolling or hot pressing.

After providing the first layer layer 4 as a layer that can be treated alone as described above, the second layer layers 6 can be formed on this layer. In this case, a slip containing the ceramic particles 5 , a dispersing agent and a binder is provided and the layer for the first layer 4 is immersed in the slip. The immersion process can effectively produce the unsintered laminate 1 with the second layer layers 6 provided on both surfaces of the first layer layer 4 . The thickness of the second layer layers 6 can be controlled by the content of the ceramic particles 5 in the slip and by the immersion time.

The binder and the dispersing agent, which are shown in FIGS. 1A and 1B as carrier medium 8 , in the slip for the second layer layers 6 can be the same or different to the binder and dispersing agent in the slip for the first layer layer 4 .

Instead of the immersion process, the second layer layers 6 can be formed by spraying, roll-cladding or printing the slip containing the ceramic particles 5 . Alternatively, the unsintered laminate 1 can be provided by providing the second layer layers 6 as layers that can be treated alone, as in the first layer layer 4 , and by superimposing the second layer layers 6 on the first layer layer 4 .

It is preferred that the ceramic particles 5 in the layers 6 have a high wettability for the glass powder 3 in the first layer 4 . A preferred ceramic material for the ceramic particles 5 is aluminum oxide. Examples of other useful ceramic materials include MgO, ZrO ₂ , SiO ₂ and TiO ₂ .

The unsintered laminate 1 is preferably pressed in the laminated direction before the tempering. During the tempering process, a temperature is applied which does not cause the ceramic particles 5 to sinter, but does cause the glass powder 3 to melt. During the annealing process, the carrier medium 7 in the first layer layer 4 and the carrier medium 8 in the second layer layers 6 are removed, while the glass powder 3 in the first layer layer 4 is melted as melting glass to form the first layer layer 4 as shown in FIG. 1B tie. In addition, part of the melting glass 9 penetrates into the second layer layers 6 by means of capillary force, enters the spaces between the ceramic particles 5 and binds the ceramic particles 5 together.

The surface roughness of the two main surfaces of the resulting composite laminate 2 depends on the size of the ceramic particles 5 in the second layer layers 6 . Thus, the use of ceramic particles 5 with small sizes can reduce the surface roughness of the composite laminate 2 , even if the glass powder 3 has a relatively large particle size.

If the size of the ceramic particles 5 in the second layer layers 6 is smaller, the second layer layers 6 are denser. In this case, the capillary force inducing a viscous flow of the melting glass 9 is increased and the melting glass 9 is packed more densely.

In addition, the melting glass 9 reaches the outer surfaces of the second layer layers 6 and the surface tension of the melting glass 9 smoothes these surfaces. Accordingly, the melting glass 9 also contributes to an improved flatness of the two main surfaces of the composite laminate 2 .

Figs. 2A and 2B show another embodiment of the invention and corresponding to Fig. 1A and 1B. In Fig. 2A and 2B, the same components shown in Fig. 1A and 1B are indicated by the same reference numerals and their description will be omitted.

In the embodiment shown in FIGS . 2A and 2B, a first layer layer 4 a of an unsintered laminate 1 a shown in FIG. 2A contains not only the glass powder 3 but also a ceramic filler 10 . Thus, the first layer 4 a of the composite laminate 2 a shown in FIG. 2B contains the ceramic filler 10 in addition to the melting glass 9 .

The ceramic filler 10 may differ from the ceramic particles 5 contained in the second layer layers 6 with respect to particle size and material or may be the same.

Other configurations and the manufacturing method of the second embodiment shown in FIGS. 2A and 2B are substantially the same as those of the embodiment shown in FIGS. 1A and 1B.

Since the first layer layer 4 a contains the ceramic filler 10 , the resulting composite laminate 2 a has improved mechanical strength.

In both the in Figs. 1A and 1B shown composite laminate 2 as a composite laminate also in the example shown in Fig. 2A and 2B Ver 2 a second film layer 6, the finer by using ceramic particles 5 are flat surfaces he witnesses can disposed at outer sides. If the composite laminate 2 or 2 a is used as a circuit board, an outer conductive film with a fine circuit pattern can be easily formed on the main surface thereof, which leads to high-density wiring on the circuit board.

The composite laminate 2 or 2 a may comprise inner conductors, for example an inner conductive film and a contact hole.

Fig. 3 is a schematic cross sectional view of a composite laminate 11 provided with the above-mentioned outer conductors of the films and inner conductors. The composite laminate 11 comprises a first layer layer 12 , which corresponds to the first layer layer 4 or 4 a in the above embodiments, and second layer layers 13 , which correspond to the second layer layers 6 in the above embodiment. These second layer layers 13 form two outer surfaces, that is to say main surfaces of the composite laminate 11 .

The composite laminate 11 has outer conductive films 14 , 15 , 16 , 17 and 18 , which are formed on these main surfaces, and inner conductors formed therein, for example inner conductive films 19 , 20 , 21 , 22 , 23 and 24 and contact holes 25 , 26 , 27 , 28 , 29 and 30 . The inner conductive films 19 and 20 are formed along the interface between the first layer 12 and the upper second layer 13 . As shown by the geometrical arrangement of the inner conductive films 21 to 24 and the contact hole contacts 27 to 30 , the first layer layer 24 is formed by laminating a plurality of unsintered layers, each of which has a predetermined conductor pattern for the inner conduct films 19 to 24 and the contact hole contacts have 25 to 30 .

In addition, every second layer layer 13 can be formed by laminating a plurality of unsintered layers. In this case, the inner conductive films can be easily formed inside the second layer layer 13 .

Examples 1 to 4 and Comparative Examples 1 to 5

Composite panels of Examples 1 to 4 according to the invention and Comparative Examples 1 to 5 were as in Table 1 shown to assess surface roughness.

The glass powder contained in the first layer layer consisted of crystallized anorthite glass and had a particle size of approximately 6.50 μm in examples 1 to 4 and a particle size of approximately 3.63 μm to approximately 7.47 μm in comparative examples 1 to 4th The first layer in Comparative Example 5 contained no glass powder.

The first layer layer contained powdered aluminum oxide with a particle size of approximately 0.35 μm as the ceramic Filler in all composite panels.

The glass powder and the ceramic filler were mixed at a weight ratio of 60:40. In the case of play 1 to 4 and in Comparative Examples 1 to 4 the mixture was water as a dispersant and a Bu tyral resin added as a binder or were added to the ceramic filler in Comparative Example 5 to form the slip. Bubbles in the slip were removed and a scraper blade method was used to remove one unsintered layer formed so that the dried thickness was 500 microns.

Using powdered alumina with a particle size of about 0.35 μm to 0.60 μm as ceramic powder, an aqueous slip was produced to form the second layer layers of Examples 1 to 4, so that the solids content was 10 percent by volume.

The unsintered layer for the first layer layer was immersed in the slip and dried to form ceramic La to form with a thickness of about 10 microns as second layer layers on the two surfaces of the green layer the.

Each unsintered laminate was pressed under a pressure of 100 kg / cm ² using a rigid press, and was in air in Examples 1 to 4 and Comparative Examples 1 to 4 at 850 ° C and 1,500 ° for two hours C heated in Comparative Example 5 to form a plate. The surface roughness Ra of each plate is shown in Table 1.

Table 1

Table 1 shows that the surface roughness Ra of each plate with the second layer layers is in a range of 0.17 µm to 0.48 µm. The surface roughness Ra depends on the particle size in the second layer layers holding ceramic powder. This means that the surface flatness is improved if the particle size of the kera mixing powder decreases.

The surface roughness Ra in Examples 1 to 4 compared to the surface roughness Ra of 0.80 µm of Ver same example 3, which was produced under the same conditions, but without the formation of the second layer layers, significantly reduced.

Compared to Comparative Examples 1 to 4, the surface roughness decreases when the particle size of the glass powder verse decreases. As shown in Comparative Example 1, however, the particle size of the glass powder must be approximately 3.63 μm be reduced to obtain a surface roughness comparable to that in Examples 1 to 4. Such a small particle size is impractical due to the high manufacturing cost of producing the glass powder.

If the second layer layers are not formed on the first layer layer, which only contains the ceramic filler, as shown in Comparative Example 5, the surface roughness Ra is 0.20 μm and is at a satisfactory level. In such a case, however, the heating temperature must be increased to 1,500 ° C. Thus, there is a limitation of metals that can be used as inner conductive films 19 to 24 and via contacts 25 to 30 . Such a low surface roughness is easily achieved, for example, by reducing the particle size of the ceramic powder in the second layer layers to 0.35 μm, as shown in Example 1.

The present invention can refer to various modifications of the above-described embodiments include the drawings in the examples shown in Table 1.

The number of the first layer layers and the second layer layers and the order of their lamination can be according to required designs can be changed as long as every second layer is in contact with every first layer takes place and the second layer layers form at least one main surface of the composite laminate.

The first layer layer can have any thickness. The second layer layers can also have any thickness, as long as the glass melted in the first layer layer partially penetrates the second layer layers and the particles of the ceramic powder in the second layer layers.

The unsintered layer for the first layer layer can be glass fibers, glass whiskers, glass flakes or glass plates Place of the glass powder included.

The present invention is also applicable to a composite laminate which is provided with recesses which open have openings along outer surfaces. Such recesses are ge in the green composite laminate forms and are used to hold electronic components when the composite laminate is more laminated circuit board is used.

Claims (11)

1. composite laminate comprising:
at least one first layer layer containing glass and
at least one second layer layer containing ceramic particles in contact with the first layer layer,
characterized in that the second layer layer represents at least one main surface of the composite laminate, the ceramic particles are unsintered in the second layer layer and that glass contained in the first layer layer has melted and partially penetrated into the second layer layer, so that the ceramic particles are connected to one another. 2. Composite laminate according to claim 1, characterized in that the first layer layer further comprises a kerami filler. 3. The composite laminate of claim 1 or 2, further comprising an outer conductive film attached to the is formed by the second layer layer provided main surface. 4. Composite laminate according to one of claims 1 to 3, which further comprises an inner conductor provided therein summarizes. 5. A method of making a composite laminate comprising:
a first step of producing an unsintered composite laminate which comprises at least one first layer layer containing glass and at least one second layer layer containing ceramic particles, where the second layer layer is in contact with the first layer layer, the second layer layer represents at least one main surface of the composite laminate , and
a second step of annealing the composite non-sintered laminate at a temperature which does not sinter the ceramic particles but causes the glass to melt, so that the first layer is bonded by melting the glass in the first layer and part of the molten glass into the second layer layer penetrates to connect the ceramic particles together. 6. A method for producing a composite laminate according to claim 5, characterized in that in the first Step the glass in the first layer layer is pulverized and the ceramic particles in the second layer grain have sizes that are smaller than that of the glass powder. 7. The method for producing a composite laminate according to claim 5 or 6, characterized in that in the first step the first layer layer further comprises a ceramic filler. 8. A method for producing a composite laminate according to any one of claims 5 to 7, wherein in the first step the first layer is provided as a layer that can be treated alone, and the second layer on the Layer is formed for the first layer layer. 9. A method for producing a composite laminate according to one of claims 5 to 7, characterized in that that in the first step the first layer layer and the second layer layer as a first layer and a second Layer are provided, which can be treated individually, and the first layer and the second layer are stacked on top of each other to form an unsintered composite laminate. 10. A method for producing a composite laminate according to any one of claims 5 to 9, which further comprises a Step of forming an outer conductive film on the at least one formed by the second layer main surface. 11. A method for producing a composite laminate according to one of claims 5 to 10, characterized in that that the first step includes forming an inner conductor inside the composite green laminate.