KR100528693B1 - Fabricating method for low-temperature co-firing ceramic multi-layer substrate - Google Patents

Abstract

The present invention relates to a method for producing a low temperature cofired ceramic multilayer substrate which can be produced using a dissimilar material.

A method for manufacturing a low temperature cofired ceramic multilayer substrate according to the present invention comprises the steps of: preparing a plurality of green tapes having different firing temperatures, permittivity and permeability; Stacking and bonding the green tapes such that green tapes having a high firing temperature among the green tapes are positioned on a top layer and a top layer; Low temperature co-firing of the bonded green tapes; And removing green tapes having a high temperature at the firing temperature located at the uppermost layer and the lowermost layer from the fired green tapes.

Description

Manufacturing method of low temperature cofired ceramic multilayer board {FABRICATING METHOD FOR LOW-TEMPERATURE CO-FIRING CERAMIC MULTI-LAYER SUBSTRATE}

The present invention relates to a method for manufacturing a low temperature cofired ceramic multilayer board, and more particularly, to a method for manufacturing a low temperature cofired ceramic multilayer board which can be made of different materials.

Recently, as functions of electronic products are complicated and various electronic devices are miniaturized, circuits for driving electronic devices are also becoming highly integrated. Accordingly, the type and quantity of large scale integrated circuits (LSIs) among semiconductor devices applied to electronic products are also increasing. In order to apply such a semiconductor device, a method of packaging a device is also becoming complicated and diversified. In response to this trend, a high-integration circuit can be configured by using a multi-chip module (hereinafter, referred to as "MCM") technology for simultaneously packaging a plurality of semiconductor devices on a single substrate.

1 and 2 is a view showing a manufacturing process of a conventional MCM package.

1 and 2, the manufacturing process of the MCM package is started by cutting the green tape wound on the roll 12 to a predetermined size (step S21). Here, the green tape is applied to the glass powder of the glass powder. Binder to maintain viscosity, plasticizer to provide flexibility to prevent hardening, a solvent and a small amount of additives to dissolve the binder and the plasticizer is dried, and then the slurry is tape-cast to a certain thickness It is formed by processing into a roll and wound on the roll 12.

Four green tapes 13a to 13d prepared by the step S21 are formed with a plurality of via holes 16 by mechanical punching.

Subsequently, after the conductive paste 18 is filled in the via hole 16, the filled paste 18 is dried. (Step S23) The conductive material 18 filled in the via hole 16 is formed in each green in a later process. It serves to electrically connect each of the circuit patterns 20 formed on the tapes 13a to 13d.

After the conductive material is filled in the via hole 16 by the step S23, the circuit patterns 20 are formed on the green tapes 13a to 13d by using a screen printing method or the like (step S24).

The solder resist material is coated on the green tape 13d of the lowest layer in which the input / output pad is formed among the green tapes 13a to 13d on which the circuit pattern 20 is formed in step S24. The solder resist material is coated on the entire surface of the green tape 13d of the lowest layer excluding the input / output pads.

In operation S25, the other green tapes 13a to 13c are aligned on the green tape 13d of the lowest layer on which the solder resist is coated.

When the four green tapes 13a to 13d are aligned in a stacked form by the step S26, the four green tapes 13a to 13d are laminated by the laminating process (step S27).

The green tapes 13a to 13d joined by the step S27 are co-fired by a predetermined heat. (Step S28) Each of the green tapes 13a to 13d cofired by the step S28 is made of ceramic. Serving as a substrate, the ceramic substrates stacked by the step S28 becomes a circuit package 15 having a plurality of circuit layers.

The upper surface of the package 15 prepared by the step S28 is a passive device such as a resistor (R), an inductor (L), a capacitor (C), a transistor (Transister), an integrated circuit chip (IC) An active element 2 or the like is mounted.

On top of the package 6, that is, on the front surface, a material 5 serving as a protective layer is coated on the entire surface (step S30).

Finally, each of the solder balls 3 is attached to each of the input / output pads located on the bottom of the package 10 by using a solder ball reflow process (step S31).

At this time, if necessary, after firing the laminated substrate, a process of plating an electrode pad on the substrate is added to form the MCM package 10.

The MCM package is a ball mounted on an electrode pad on a printed circuit board (hereinafter referred to as "PCB") or another substrate by solder balls 3 positioned on the back side of the package as shown in FIG. It is manufactured in a grid array (hereinafter referred to as "BGA") method. As the substrate material for the MCM package, a ceramic material having a high wiring density, excellent thermal characteristics, and excellent frequency characteristics is used. Examples of such ceramic substrates are alumina or low temperature cofired ceramic substrates. The MCM package is typically manufactured using aluminum nitride (AlN), alumina (Al 2 O 3), or oxides of glass and metal, and the thermal expansion coefficient of this ceramic substrate is about 4 to 7 ppm / ° C.

However, in the related art, the MCM package has used the same substrate material for each layer in order to solve the problem of mismatch of substrates stacked due to shrinkage of the ceramic substrate generated during the firing process. That is, when the dissimilar material substrate is used, the amount of plastic shrinkage is different because the composition and type of the metal oxide and the glass component constituting the substrate are different. When the different materials are laminated and fired at the same time, warpage or cracking of the substrate may occur due to mismatch due to the plastic shrinkage difference. However, as the functions of electronic products such as mobile communication devices become more complicated and lighter, shorter and smaller, the components of these products are miniaturized and complex modular. Accordingly, the characteristics of a single kind of substrate material are limited in achieving the market demand for composite components and composite modules. For example, a single dielectric constant substrate has limitations in simultaneously implementing a high wiring density circuit configuration and mounting of various passive element components (inductors, filters, capacitors, resistors, etc.). That is, a substrate material having low dielectric constant should be used for high speed wiring, and a substrate material having low dielectric constant and low dielectric loss should be used for a high frequency inductor and a low capacitance capacitor. In addition, a substrate material having high permeability characteristics should be used for a high capacity inductor, and a substrate material having high dielectric constant and low dielectric loss characteristics should be used for a high capacity capacitor and a small planar filter. However, the MCM package made of a single type of substrate material has a disadvantage in that it is difficult to simultaneously implement various passive devices by layering each passive device for miniaturization of a package.

Accordingly, it is an object of the present invention to provide a method for producing a low temperature cofired ceramic multilayer substrate which can be made of different materials.

In order to achieve the above object, the method for manufacturing a low-temperature cofired ceramic multilayer substrate according to the present invention includes the steps of preparing green tapes having different firing temperatures, permittivity and permeability; Stacking and bonding the green tapes such that green tapes having a high firing temperature among the green tapes are positioned on a top layer and a top layer; Low temperature co-firing of the bonded green tapes; And removing the green tape having the high temperature of the firing temperature positioned at the uppermost layer and the lowest layer from the fired green tapes. The method of manufacturing the low temperature cofired ceramic multilayer substrate has a high firing temperature. And forming a circuit pattern on the remaining green tapes except for the green tape. The high temperature is 1500 ° C. or more. The low temperature is 800 ° C. or more and 1000 ° C. or less. The remaining green tapes except for the high temperature green tape are at least two sheets, and at least one of the two or more green tapes has a material different from that of the remaining green tapes. The green tape having a high temperature may include the bonded green tapes at the low temperature co-firing of the bonded green tapes. The method of manufacturing the low temperature cofired ceramic multilayer substrate includes attaching a solder ball to an external input / output terminal of the remaining green tapes from which the green tape having a high firing temperature is removed. It features.

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Other objects and advantages of the present invention in addition to the above object will be apparent from the description of the preferred embodiment of the present invention with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 4 to 6.

4 is an exploded perspective view illustrating a method of manufacturing a low-temperature cofired ceramic multilayer substrate using different materials according to an embodiment of the present invention.

Referring to FIG. 4, the manufacturing process of the low-temperature cofired ceramic multilayer substrate is started by cutting the green tape wound on the roll to a predetermined size. (Step S41) Each green tape 33a to 33d has a temperature that is fired. The dielectric constant and permeability characteristics are different. Here, the green tape may be a binder containing a binder for maintaining the viscosity of the glass powder in a glass powder, a plasticizer for providing flexibility to prevent hardening, a solvent for dissolving the binder and the plasticizer, and other small amounts of additives. After drying, the slurry is formed by processing to a constant thickness with a tape casting method and wound on a roll.

In the three green tapes 33a to 33c except for the high-temperature fired green tape 33d provided by step S41, a plurality of via holes are formed by mechanical punching (step S42).

Subsequently, after the conductive paste is filled in the via hole, the filled paste is dried. (Step S43) The conductive material filled in the via hole is formed on each of the circuit patterns formed on the green tapes 33a to 33c in a later process. It serves to make electrical connections. At this time, Ag, Cu, Au and the like are generally used as the conductive material.

After the conductive material is filled in the via hole by the step S43, circuit patterns are formed on the green tapes 33a to 33c by using a screen printing method or the like.

The green tapes 33a to 33c each having the circuit pattern formed by the step S44 are aligned, and the hot-fired green tapes 33d capable of high-temperature firing (for example, 1500 ° C. or higher) are stacked on the uppermost layer and the lowermost layer, respectively. After the laminating process, the green tapes are laminated in a laminated form (step S45). Green tapes containing metal oxides such as Al ₂ O ₃ , ZrO, SiC, AlN, and Mullite are generally used for high temperature firing. Green tapes 41 are used.

The green tapes 33a to 33d aligned at step S45 are co-fired by a predetermined heat (step S46). That is, the firing process is performed at a low temperature of about 800 ° C to 1000 ° C. When the low temperature firing process is performed, the plastic shrinkage of the high temperature firing green tapes 33d positioned in the uppermost layer and the lowermost layer does not occur. Accordingly, the green tapes 33a to 33c of the dissimilar material in which the circuit pattern is formed are suppressed in the plane direction (for example, the X axis and the Y axis) and are restricted only in the thickness direction (for example, the Z axis). Contraction.

When the stacked green tapes 33a to 33d are fired, the high-temperature fired green tapes 33d stacked on the top and bottom layers are removed (step S47). At this time, the hot-fired green tapes 33d are washed with water. It can be removed through a process such as. Each of the green tapes 33a to 33c of the dissimilar material simultaneously fired by the step S47 serves as a circuit board and becomes a circuit package 35 having a plurality of such circuit layers.

When the green tapes 33d of the uppermost layer and the lower layer are removed by the step S47, the input / output on the green tape 33a of the lowest layer on which the external input / output pad is formed among the green tapes 33a to 33c on which the circuit pattern is formed, respectively. Solder resist is coated on the entire surface of the green tape 33a of the lowest layer except for the pad. The top surface of the package 35, that is, the front surface, is coated with a material 5 serving as a protective layer. Finally, each of the solder balls 3 is attached to each of the input / output pads located at the bottom of the package 35 using a solder ball reflow process (step S48).

At this time, if necessary, after firing the stacked substrates, a process of plating the electrode pads on the substrate is added to form a dissimilar material low temperature cofired ceramic multilayer substrate package 30. In addition, the MCM package 30 manufactured by the method for manufacturing a heterogeneous low-temperature cofired ceramic multilayer substrate according to an embodiment of the present invention has four green tapes for the substrate, but the MCM package has a large number according to the circuit configuration to be manufactured. It can be formed by stacking the green tape for the substrate. In addition, the MCM package 30 manufactured through the manufacturing method according to an embodiment of the present invention is laminated by stacking green tapes having different material properties for each layer depending on the circuit configuration to be manufactured as shown in FIG. By incorporating passive elements, it is possible to manufacture highly integrated, light and small composite modules. That is, one layer may have a substrate having low dielectric constant and low dielectric loss characteristics for high density wiring and a low loss line, and another layer may have a substrate having high dielectric constant and low dielectric loss characteristics for capacitors and filters. . In the lower layer, a substrate having a high permeability characteristic for implementing a high capacitance inductor may be stacked.

FIG. 6 is a cross-sectional view illustrating a state in which the MCM package 30 fabricated by dissimilar material low temperature co-fired ceramic multilayer substrate manufacturing method according to an embodiment of the present invention is mounted on a PCB.

Referring to FIG. 6, the MCM package 30 composed of dissimilar materials according to an exemplary embodiment of the present invention may be formed on the solder ball 3 mounted on the external electrode pattern of the PCB substrate and the external input / output pads of the MCM package 30. Is electrically connected to the PCB substrate.

As described above, the method for manufacturing a low temperature cofired ceramic multilayer board according to an embodiment of the present invention is carried out when the low temperature cofired is performed by laminating a high temperature firing substrate on the uppermost layer and the lowermost layer of a multilayer ceramic substrate composed of laminated dissimilar materials. Plastic shrinkage occurs only in the thickness direction of the substrate. As a result, the multi-chip module manufactured by the multi-chip module manufacturing method according to the embodiment of the present invention can incorporate various passive devices by applying a shrinkage-free sintering method that does not occur in a planar shrinkage of a multilayer ceramic substrate composed of dissimilar materials. Will be. As a result, the multi-chip module manufacturing method according to the embodiment of the present invention enables the miniaturization and complex modularization of the composite component.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

1 is an exploded perspective view clearly showing a manufacturing process of a conventional multi-chip module package.

FIG. 2 is a flowchart illustrating a manufacturing process of the multi-chip module package illustrated in FIG. 1 in stages.

3 is a cross-sectional view showing that the multi-chip module package shown in FIG. 1 is mounted on a printed circuit board.

4 is an exploded perspective view clearly showing a manufacturing process of a low-temperature cofired ceramic multilayer substrate using a dissimilar material according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating the low temperature co-fired multilayer substrate shown in FIG. 4.

FIG. 6 is a cross-sectional view illustrating the low temperature co-fired ceramic multilayer substrate illustrated in FIG. 4 mounted on a printed circuit board.

<Explanation of symbols for the main parts of the drawings>

1: solder resist 2: integrated circuit and passive device

3: solder ball 5: coating material

10,30: multi-chip module package 12: green tape roll

13a, 13b, 13c, 13d, 13e, 33a, 33b, 33c, 33d: green tape

16: via hole 18: conductive material

20: electrode pattern 35: ceramic multilayer substrate

51: printed circuit board 54: electrode pad

Claims (7)

Preparing green tapes having different firing temperatures, permittivity and permeability; Stacking and bonding the green tapes such that green tapes having a high firing temperature among the green tapes are positioned on a top layer and a top layer; Low temperature co-firing of the bonded green tapes; And removing the green tape having the high temperature of the firing temperature located in the uppermost layer and the lowermost layer from the fired green tapes. The method of claim 1, And forming a circuit pattern on the remaining green tapes other than the green tape having the high firing temperature. The method of claim 1, The high temperature is 1500 ℃ or more method for producing a low-temperature cofired ceramic multilayer board, characterized in that. The method of claim 1, The low temperature is 800 ℃ ℃ 1000 ℃ low temperature co-fired ceramic multilayer substrate manufacturing method characterized in that. The method of claim 1, The remaining green tape is at least two sheets except for the green tape having a high firing temperature. At least one of the two or more green tapes has a material different from that of the remaining green tapes. The method of claim 1, Green tape having a high temperature of firing, The method of manufacturing a low-temperature co-fired ceramic multilayer board, characterized in that to prevent the bonded green tapes shrink in the plane direction in the step of co-fired the green tapes at low temperature. The method of claim 1, And attaching a solder ball to the external input / output terminals of the remaining green tapes from which the green tape having a high firing temperature is removed.