KR100566052B1 - Built-in capacitor using dissimilar dielectrics and method of manufacturing the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a built-in capacitor using a heterogeneous dielectric and a method of manufacturing the same, wherein the dielectric between the upper and lower electrodes has a relatively low dielectric constant and a dielectric having a high dielectric constant filled in the via holes of the green sheet. By forming the film, there is no need to worry about the warpage of the module substrate due to the mismatch of shrinkage and thermal expansion coefficient which may occur when the heterogeneous dielectric is produced by green sheet, and the unnecessary waste of material can be prevented, and the dielectric paste printing Since the process is simpler than the method using the method and the thickness can be formed, the characteristic deviation can be reduced in the substrate, and the device can be miniaturized by fabricating a built-in capacitor of high capacitance using heterogeneous dielectrics. .

Heterogeneous, Dielectric, Capacitor, Green Sheet, Via Hole, Plastic

Description

Built-in capacitor using dissimilar dielectric and its manufacturing method {Built-in capacitor using dissimilar dielectrics and method of manufacturing the same}

1a to 1d is a manufacturing process diagram of a built-in capacitor using a heterogeneous dielectric according to the present invention

2A to 2D are plan and cross-sectional views illustrating a process of manufacturing a first green sheet of a built-in capacitor using a heterogeneous dielectric according to the present invention.

3A to 3C are plan and cross-sectional views illustrating a process of manufacturing a second green sheet of a built-in capacitor using a heterogeneous dielectric according to the present invention.

4A to 4C are plan and cross-sectional views illustrating a process of manufacturing a third green sheet of a built-in capacitor using a heterogeneous dielectric according to the present invention.

<Description of Symbols for Main Parts of Drawings>

100,110,120 Green Sheet 101,121,111 Via Hole

102: dielectric film 105: upper electrode

112,122: conductive material 115,127: electrode pad

125: lower electrode 200: tape

The present invention relates to a built-in capacitor using a heterogeneous dielectric and a method of manufacturing the same. More particularly, the dielectric material between the upper and lower electrodes has a high dielectric constant filled in the green sheet having a relatively low dielectric constant and via holes of the green sheet. By forming a dielectric film having a dielectric layer, it is not necessary to be concerned about the warpage of the module substrate due to the shrinkage rate and thermal expansion coefficient mismatch that may occur when the heterogeneous dielectric is made of a green sheet and fired, and it is possible to prevent unnecessary waste of materials. Since the process is simpler than the method using dielectric paste printing, and the thickness can be formed, the characteristic deviation can be reduced in the substrate, and the device can be miniaturized by fabricating a high capacitance internal capacitor using heterogeneous dielectrics. Embedded capacitors using heterogeneous dielectrics It relates to a manufacturing method thereof.

In general, low temperature calcined multilayer ceramic circuit boards have the advantage of being able to use low melting point conductive metals such as silver, gold, and copper.

In addition, low-temperature calcined multilayer ceramic circuit boards are made of glass-ceramic composites fired at temperatures below 1000 ° C as the main raw material and have a low coefficient of thermal expansion, which is similar to that of silicon (Si) or gallium arsenide (GaAs) devices. Therefore, it can be used as a package substrate of an integrated circuit.

In addition, it has the advantage that the passive elements such as resistors, capacitors, inductors, etc. can be embedded in the green sheet stacking technology.

In particular, embedded ceramic capacitors are manufactured for low temperature fired ceramic circuit boards, and are applied to high frequency modules.

In order to manufacture such a built-in ceramic capacitor for a high frequency module, first, a green sheet must be made.

The green sheet is made by mixing a powder of a glass-ceramic composite with an organic binder, a solvent, a dispersant, and the like to produce a slurry, and passing the slurry through a tape caster to form and dry it.

Thereafter, the conductive paste prepared by mixing a conductive metal powder such as silver and gold, an organic binder, a solvent and a glass powder, and the like is screen printed on the green sheet.

Here, the screen printing method is a method of printing a desired electrode pattern on the upper part of the green sheet by passing the paste only through the upper part of the screen mask on which the pattern is formed and passing through the pattern part.

As described above, after the conductive paste is printed to be alternately printed on the green sheets, the green sheets are laminated and fired to form a ceramic package substrate in which a capacitor is embedded.

Of course, each of the green sheets may be electrically connected to each other by vias pre-drilled and filled with conductive paste.

Such a method of using the green sheet itself as a dielectric layer is mainly to use the low dielectric constant of the low-temperature fired ceramic. The two electrodes printed with the conductive paste on the green sheet are alternately printed with a plurality of alternating capacitors to have a desired capacity. I can make it.

Also, as a second method of manufacturing the embedded ceramic capacitor, there is a method of forming a dielectric layer using a dielectric paste on the green sheet.

In this method, first, the conductive paste is printed on the green sheet, dried to form a lower electrode, and then a dielectric paste is printed on the lower electrode.

At this time, the printing thickness or the number of times of the dielectric is adjusted to obtain the desired capacity.

Then, after drying, the upper electrode is printed, a capacitor structure is made, and the printed sheet is stacked together with other layers of green sheets, embedded, and then fired to complete another type of embedded capacitor.

The manufacturing method of the two built-in capacitors described above has a difficulty in embedding a fixed capacitance capacitor.

First, in the method using the green sheet itself, it is not possible to reduce the size of the device because a capacitor having a high capacitance can be manufactured only by increasing the size of the electrode.

As a solution to this, a method of realizing a heterogeneous laminate by fabricating a material having a high dielectric constant into a green sheet has been attempted, but a stable property is obtained due to a decrease in warpage or plastic density due to a mismatch of shrinkage rate and thermal expansion coefficient. Is hard.

In addition, if the heterogeneous dielectric layer is not effectively utilized, the loss of unnecessary areas increases.

In addition, since the method of printing the dielectric paste has a thickness deviation for each position due to the characteristics of screen printing, there is a disadvantage in that the characteristic deviation is large in the entire substrate, and it is difficult to keep up with the trend of requiring the minimum allowable deviation.

Further, by printing several times to control the thickness of the dielectric, there is a fear that the capacitor portion becomes relatively thick in the stacked elements, and cracks occur after firing.

Accordingly, the present invention has been made to solve the problems described above, the dielectric material between the upper and lower electrodes is a green sheet having a relatively low dielectric constant and a dielectric having a high dielectric constant filled in the via holes of the green sheet By forming the film, there is no need to worry about the warpage of the module substrate due to the mismatch of shrinkage and thermal expansion coefficient which may occur when the heterogeneous dielectric is produced by green sheet, and the unnecessary waste of material can be prevented, and the dielectric paste printing Since the process is simpler than the method using the method and the thickness can be formed, it is possible to reduce the characteristic deviation in the substrate, and by using the heterogeneous dielectric, a built-in capacitor having a high capacitance can be used to produce a heterogeneous dielectric that can be miniaturized. To provide a built-in capacitor and a method of manufacturing the same Its purpose is to.

According to a preferred aspect of the present invention, a plurality of spaced apart via holes are formed, a dielectric film is filled in each of the via holes, and a top of the dielectric film filled in each of the via holes is formed. A first green sheet having an upper electrode formed thereon;

A second green sheet having a via hole filled with a conductive material therein to be electrically connected to the upper electrode of the first green sheet, and having an upper electrode pad electrically connected to the conductive material thereon; ;

A lower electrode contacting a lower portion of the dielectric layer of the first green sheet is formed at an upper portion, and a via hole filled with a conductive material is formed therein so as to be electrically connected to the lower electrode, and is electrically connected to the via hole. The electrode pad is composed of a third green sheet formed below,

A first layer on the third green sheet such that the dielectric film of the first green sheet is in contact with the lower electrode of the third green sheet, and the conductive material of the second green sheet is in contact with the upper electrode of the first green sheet. The green sheet and the second green sheet are stacked in sequence,

There is provided an embedded capacitor using a heterogeneous dielectric, wherein the dielectric constant of the dielectric film and the dielectric constant of the first green sheet are different.

According to another preferred aspect of the present invention, a plurality of spaced apart via holes are formed, a dielectric film is filled in each of the via holes, and an upper portion of the dielectric film is filled in each of the via holes. A first step of forming a first green sheet having a surrounding upper electrode and having a dielectric constant smaller than that of the dielectric film;

A via hole filled with a conductive material is formed therein so as to be electrically connected to the upper electrode of the first green sheet, and a second green sheet having an upper electrode pad electrically connected to the conductive material is formed thereon. Performing a second step;

A lower electrode contacting a lower portion of the dielectric layer of the first green sheet is formed at an upper portion, and a via hole filled with a conductive material is formed therein so as to be electrically connected to the lower electrode, and a lower electrically connected to the via hole. A third step of forming a third green sheet having an electrode pad formed thereon;

A first layer on the third green sheet such that the dielectric film of the first green sheet is in contact with the lower electrode of the third green sheet, and the conductive material of the second green sheet is in contact with the upper electrode of the first green sheet. Stacking the green sheet and the second green sheet sequentially;

After the fourth step, a method of manufacturing an embedded capacitor using a heterogeneous dielectric composed of a fifth step of firing is provided.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1A to 1D are manufacturing process diagrams of a built-in capacitor using a heterogeneous dielectric according to the present invention. First, a plurality of spaced apart via holes 101 are formed, and a dielectric film 102 is formed in each of the via holes 101. A first green sheet 100 is formed, and the first green sheet 100 having the upper electrode 105 surrounding the top of the dielectric film 102 filled in each of the via holes 101 is formed (FIG. 1A).

Here, the dielectric constant of the dielectric film 102 and the first green sheet 100 is different, and in this case, the dielectric constant of the dielectric film 102 is preferably larger than the dielectric constant of the first green sheet 100.

In addition, as illustrated in FIG. 1B, a via hole 111 filled with a conductive material 112 is formed therein so as to be electrically connected to the upper electrode 105, and electrically connected to the conductive material 112. The upper electrode pad 115 is formed to form a second green sheet 110 formed thereon.

In this case, the conductive material 112 preferably uses a conductive paste.

Next, a lower electrode 125 contacting the lower portion of the dielectric film 102 of the first green sheet 100 is formed thereon, and a conductive material 122 is formed therein so as to be electrically connected to the lower electrode 125. ) Is filled with a via hole 121, and a third green sheet 120 having a lower electrode pad 127 electrically connected to the via hole 121 is formed below (FIG. 1C).

Lastly, as shown in FIG. 1D, the dielectric film 102 of the first green sheet 100 contacts the lower electrode 125 of the third green sheet 120, and the first green sheet ( The third green sheet 120, the first green sheet 100, and the second green sheet 110 are sequentially disposed such that the conductive material of the second green sheet 110 contacts the upper electrode 105 of the 100. When laminated at 0, and fired at 800 to 900 ° C., a low temperature co-fired ceramic module having a fixed capacitance built-in capacitor according to the present invention is produced.

Here, in the present invention, the dielectric constant of the first to third green sheets 100, 110 and 120 is lower than that of the dielectric film 102, and the low dielectric constant green sheet and the high dielectric constant dielectric film are fired at the same time, so that a high capacitance capacitor It can be prepared.

Therefore, the first to third green sheets 100, 110, and 120 described above form a slurry produced by mixing a low dielectric constant low temperature co-fired ceramic powder with an organic binder, a solvent, a dispersant, and the like through a tape caster, and drying the green sheet. To prepare.

In addition, the dielectric film 102 is formed by filling a high-k low temperature co-fired powder in the form of a paste, filling the via hole, and drying it.

Here, the high dielectric constant low temperature co-fired powder is finished firing at a temperature similar to the firing temperature of the low dielectric constant powder, the starting point of the firing is slightly higher than the low dielectric constant powder, but the final shrinkage is preferably used a similar material.

Thus, in order to form the dielectric film 102, a vehicle composed of a solvent composed of terpinol and butyl carbitol, a binder such as ethyl cellulose, a dispersant, a leveling agent, a lubricant, and the like is prepared. The high dielectric constant paste can be prepared by mixing co-fired powder and vehicle at a ratio of about 8: 2, and then dispersing using three rollers.

In addition, the high dielectric constant paste preferably has a viscosity of 1000 to 2000 Pa · s to fill the via hole.

2A to 2D are plan and cross-sectional views illustrating a process of manufacturing a first green sheet of a built-in capacitor using a heterogeneous dielectric according to the present invention, wherein a low dielectric constant low temperature co-fired ceramic powder and an organic binder are formed on the tape 200; A slurry produced by mixing a solvent, a dispersant, and the like is cast and dried to form a first green sheet 100 (FIG. 2A).

 Thereafter, a plurality of spaced apart via holes 101 penetrating the first green sheet 100 and the tape 200 are formed by performing a punching process (FIG. 2B).

Here, the diameter d1 of the via holes 101 is preferably 100 to 500 μm, and the interval d2 between the via holes 101 is preferably 150 to 400 μm.

Next, each of the plurality of via holes 101 is filled with a paste containing a mixture of a low temperature co-fired powder and a vehicle having a dielectric constant higher than that of the first green sheet 100 and dried, thereby drying the plurality of via holes. A dielectric film 102 filled in 101 is formed (FIG. 2C).

Subsequently, an upper electrode 105 is formed on the first green sheet 100 so as to surround the dielectric film 102 (FIG. 2D).

Finally, the tape 200 is removed from the first green sheet 210.

3A to 3C are plan views and cross-sectional views illustrating a process of manufacturing a second green sheet of a built-in capacitor using a heterogeneous dielectric according to the present invention. The second formed on the tape 200 in the same manner as in FIG. 3A described above. A via hole 111 penetrating the green sheet 110 and the tape 200 is formed by performing a punching process (FIG. 3A).

Next, the via hole 111 is filled with a conductive paste, which is a conductive material 112, and dried (FIG. 3B).

Thereafter, an upper electrode pad 115 is formed on the second green sheet 110 to surround the upper portion of the via hole 111 filled with the conductive paste.

Subsequently, the tape 200 is removed from the second green sheet 110.

4A to 4C are plan and cross-sectional views illustrating a process of manufacturing a third green sheet of a built-in capacitor using a heterogeneous dielectric according to the present invention. Similarly to FIG. 3A, a third formed on the tape 200 is illustrated. A via hole 121 penetrating the green sheet 120 and the tape 200 is formed by performing a punching process (FIG. 4A).

Next, the via hole 121 is filled with a conductive paste, which is a conductive material 122, and dried (FIG. 4B).

Subsequently, the lower electrode 125 is formed on the third green sheet 120 to surround the upper portion of the via hole 121 filled with the conductive paste, and the tape 200 is formed on the third green sheet 120. After removal, the lower electrode pad 127 is formed under the third green sheet 120 (FIG. 4C).

Therefore, in the embedded capacitor using the heterogeneous dielectric of the present invention, the dielectric between the upper and lower electrodes 105 and 125 is composed of a green sheet having a relatively low permittivity and a dielectric film having a high permittivity filled in the via holes of the green sheet. Thus, it is possible to implement a fixed capacitance built-in capacitor.

Here, the dielectric constant K of the entire dielectric existing between the upper and lower electrodes must satisfy the following equation (1) according to the mixing law.

K = (V _low XK _low ) + (V _high XK _high ) ------- (1)

In this case, V _low is the volume of the low dielectric constant ceramic present between the upper and lower electrodes after firing, K _low is the dielectric constant of the low dielectric constant, and V _high is a _high dielectric constant dielectric present between the upper and lower electrodes after firing. The volume of the film, K _high is the permittivity of the _high- k dielectric film.

By using the above formula (1), after designing the capacitor of the desired capacitance, it is possible to manufacture a capacitor of a fixed capacitance through the manufacturing method of the present invention.

The embedded capacitor using the heterogeneous dielectric of the present invention is manufactured by stacking at least one green sheet having a dielectric film corresponding to the dielectric film of the first green sheet between the first green sheet and the third green sheet according to the design capacitance. You may.

Therefore, the present invention does not need to worry about warpage of the module substrate due to mismatch of shrinkage rate and thermal expansion coefficient which may occur when the heterogeneous dielectric is made of green sheet and fired, and it is possible to prevent unnecessary waste of material and to print dielectric paste. Since the process is simpler than the method using the method and can be formed to have a certain thickness, the characteristic deviation can be reduced in the substrate, and the device can be miniaturized by fabricating a built-in capacitor having a high capacitance using a heterogeneous dielectric.

As described above, the present invention is to form a heterogeneous dielectric by forming a dielectric between the upper and lower electrodes into a green sheet having a relatively low permittivity and a dielectric film having a high permittivity filled in the via holes of the green sheet. When the sheet is manufactured and fired, there is no need to worry about warpage of the module substrate due to mismatch of shrinkage coefficient and thermal expansion coefficient which may occur, and it is possible to prevent unnecessary waste of material, and the process is simpler and more constant than the method using dielectric paste printing. Since the thickness can be formed, the characteristic deviation can be reduced in the substrate, and the device can be miniaturized by fabricating a high capacitance internal capacitor using a heterogeneous dielectric.

Although the invention has been described in detail only with respect to specific examples, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims.

Claims (9)

delete delete delete A plurality of spaced apart via holes are formed, and each of the via holes is filled with a dielectric film made of a paste mixed with a low-temperature sintered powder and a vehicle, and an upper electrode is formed around the dielectric film filled in each of the via holes. A first step of forming a first green sheet having a dielectric constant less than that of the dielectric film; A via hole filled with a conductive material is formed therein so as to be electrically connected to the upper electrode of the first green sheet, and a second green sheet having an upper electrode pad electrically connected to the conductive material is formed thereon. Performing a second step; A lower electrode contacting a lower portion of the dielectric layer of the first green sheet is formed at an upper portion, and a via hole filled with a conductive material is formed therein so as to be electrically connected to the lower electrode, and is electrically connected to the via hole. A third step of forming a third green sheet having an electrode pad formed thereon; A first layer on the third green sheet such that the dielectric film of the first green sheet is in contact with the lower electrode of the third green sheet, and the conductive material of the second green sheet is in contact with the upper electrode of the first green sheet. Stacking the green sheet and the second green sheet sequentially; After the fourth step, a method of manufacturing a built-in capacitor using a heterogeneous dielectric consisting of a fifth step of firing. The method of claim 4, wherein The first step is, Casting a slurry produced by mixing a low temperature co-fired ceramic powder with an organic binder, a solvent, a dispersant, and the like on the tape, and drying the slurry to form a first green sheet;  Forming a plurality of spaced apart via holes through the first green sheet and the tape by performing a punching process; Filling each of the plurality of via holes with a paste mixed with a low temperature co-fired powder having a dielectric constant higher than that of the first green sheet and a vehicle and drying the paste to form a dielectric film filled in the plurality of via holes; Forming an upper electrode on the first green sheet to surround the dielectric film; Method of manufacturing a built-in capacitor using a heterogeneous dielectric, characterized in that the step of removing the tape from the first green sheet. The method of claim 5, wherein The viscosity of the paste filling the plurality of via holes is Method of manufacturing a built-in capacitor using a heterogeneous dielectric, characterized in that 1000 ~ 2000 Pa.s. The method of claim 4, wherein The second step, Casting a slurry formed by mixing a low temperature co-fired ceramic powder and an organic binder, a solvent, a dispersant, and the like on the tape, and drying the slurry to form a second green sheet; Forming a second green sheet formed on the tape and a via hole penetrating the tape by performing a punching process; Filling the via hole with a conductive paste of conductive material and drying the conductive paste; Forming an upper electrode pad on the second green sheet to surround an upper portion of the via hole filled with the conductive material; Subsequently, the method of manufacturing an embedded capacitor using a heterogeneous dielectric, characterized in that the step of removing the tape from the second green sheet. The method of claim 4, wherein Casting a slurry produced by mixing a low temperature co-fired ceramic powder and an organic binder, a solvent, a dispersant, and the like on the tape, and drying the slurry to form a third green sheet; Forming a third green sheet formed on the tape and a via hole penetrating through the tape by performing a punching process; Filling the via hole with a conductive paste of conductive material and drying the conductive paste; Forming a lower electrode on the third green sheet to cover the upper portion of the via hole filled with the conductive material, removing the tape from the third green sheet, and then forming a lower electrode pad on the lower portion of the third green sheet. Method for producing a built-in capacitor using a heterogeneous dielectric, characterized in that made. The method according to any one of claims 4 to 8, The firing temperature of the fifth step is, Method of manufacturing a built-in capacitor using a heterogeneous dielectric, characterized in that 800 ~ 900 ℃.

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