KR100607119B1 - Multilayer Ceramic Components - Google Patents

Abstract

The present invention comprises at least one dielectric material M ₁ layer; And at least one dielectric material M ₂ layer, in which passive elements are embedded in both layers of dielectric material M ₁ and M ₂ , the dielectric material M ₁ layer and dielectric material M ₂ layer respectively being the X and Y axis during sintering. To provide a multilayer ceramic construction that prevents shrinkage. Each layer of the multilayer ceramic construction according to the present invention can be used as a substrate for embedding passive elements and can prevent other layers with different dielectric constants from shrinking. Thus, multilayer ceramic constructions have the advantage of providing smaller circuits while providing better circuit accuracy.

Dielectric Constant, Multilayer Ceramic, Shrink-Resistant, Co-Sintering, Circuit, Sintering Temperature

Description

Multilayer Ceramic Components {MULTILAYER CERAMIC COMPOSITION}

1 is a simplified diagram showing one embodiment of a multilayer ceramic construction according to the present invention.

FIG. 2 is a diagram showing shrinkage rate measured when sintering M ₁ and M ₂ layers at the same thickness ratio of various M ₁ and M ₂ layers. FIG. M ₁ means the dielectric material according to Example 1, and M ₂ means a conventional ceramic (product name Du Pont 951 PT®) co-fired at low temperature.

The present invention relates to ceramic constructions, in particular multilayer ceramic constructions for the implementation of electronic microwave systems.

In modern electronics, interconnect circuit boards are essential to meet the requirements of lightweight, thin and small. Interconnect circuit boards have a number of micro systems, such as passive elements and metallization patterns, coupled to electronic circuits or arrangements that electrically or mechanically interconnect each other. Such passive elements and metallization patterns may be physically separated from one another and buried adjacent to each other in a single interconnect circuit board, thereby electrically connecting to and / or extending from the interconnect circuit board. Recently, ceramic constructions are commonly applied to such interconnect circuit boards.

In such ceramic constructions, composite electronic circuits generally require several insulating dielectric layers to separate the conductive layers. In order to meet the requirements for different dielectric constants (K) suitable for fabricating or embedding passive devices and metallization patterns, a series of dielectric materials with different dielectric constants is needed. For example, low dielectric constant materials are preferred to improve the speed at which internal signals are delivered for fast processing in ceramic components of the signal processing section; High dielectric constant materials are desirable for assembling capacitors as embedded passive devices. Electrically conductive paths through the dielectric layer and interconnecting the passive device and the metallization pattern are called vias. This multilayer structure makes the circuit more compact and occupies a small space.

A method of co-sintering a multilayer ceramic component printed with a metallization bias in which the metallization pattern extends through the dielectric layer and a passive element such as a resistor, capacitor or conductor to interconnect various passive elements and the metallization pattern is described herein. US Pat. No. 4,654,095, which is incorporated herein by reference. The ceramic powder may be made of high conductivity metals such as gold, silver, and copper to increase the density at temperatures that can be mixed. Specifically, densificatirons are achieved at 1000 ° C. or less, sufficiently separated to provide an error range at 1060 ° C., the melting point of gold. The dielectric layer builds up in the registry and is pressurized under appropriate temperatures and pressures, firing organic materials such as binders and plasticizers to drive off the green ceramic body. All ceramic and heterogeneous materials are sintered and thereby densified. This method is advantageously performed by firing at a time, saving manufacturing time and labor, and limiting the diffusion of mobile metal to prevent shorting between conductive layers.

However, co-firing a monolithic structure with a high K dielectric and a low K dielectric causes problems. One of these problems is changing the electrical properties, and the other is that shrinkage mismatch occurs during firing.

As electrical properties change, many conventional assemblies use materials with low and high dielectric constants, while materials with glass containing low dielectric constants increase the dielectric constant and increase the loss rate. The materials with high dielectric constants contain lead, magnesium and niobium. However, when a material having a low dielectric constant and a material having a high dielectric constant come into contact with each other at a temperature of 800 ° C. or higher during co-firing, a chemical reaction occurs due to interfacial diffusion. For this reason, the dielectric constants of both low and high dielectric constant materials change. In general, the dielectric constant of a material having a high dielectric constant is greatly reduced.                         

An electronic package in which several buffer layers are interposed between a material having a low dielectric constant and a material having a high dielectric constant is disclosed in US Pat. No. 5,757,611. Buffer layers containing between 25 and 100% barium compounds create more diverse pathways for chemical diffusion, providing additional physical barriers during the initial densification process. In addition, a bias may be formed through the buffer layer to electrically conduct the passive element portion and the signal processing portion. The glass forming additive and inorganic filler controls the shrinkage, thermal expansion and chemical compatibility of the buffer layer in contact with either the high K dielectric layer of the passive element portion or the low K dielectric layer of the signal processing portion. On the other hand, however, the buffer layer increases the thickness of the electronic package, making it unable to serve as an excellent substrate for embedding passive devices.

U. S. Patent No. 6,055, 151 discloses a different kind of multilayer ceramic green tape structure with different K's. This patent focuses on screen-printed inks on low firing temperature green tape to form embedded devices such as capacitors with tight tolerances with high positional accuracy. This capacitor layer is sandwiched between two barium titanate barrier layers with a thickness sufficient to prevent diffusion of the green tape into the low firing temperature glass. In addition, the green tape structure of the multilayer ceramic is bonded onto the metal support plate by bonding glass to prevent shrinkage. However, since the shrinkage ratio of the green tape and the metal support plate of the low firing temperature is different, it must be well controlled so that no rupture occurs during firing. On the other hand, the thickness of the multilayer ceramic green tape structure can no longer be reduced.                         

In the case of sintering, since the shrinkage ratio of the elements is not the same, the firing conditions must be changed to adjust this. Uncertainties in X and Y dimensions can also cause undesirable misregistration during assembly of large complex circuits. A method for preventing shrinkage during firing of a green ceramic body is disclosed in US Pat. No. 5,085,720. A peeling layer is applied to each of the top and bottom of the green ceramic body to form a "sandwich" structure. During firing and sintering, pressure in one direction is applied to the surface of the release layer. Pores are formed in the release layer to become escape routes of the volatile components of the green ceramic body. Since the release layer does not shrink during firing, shrinkage of the X and Y axes of the green ceramic body is reduced. However, the removal of the release layer covering both the top and bottom surfaces of the green ceramic body must be removed after sintering and firing of the conductors, resistors, and capacitors present thereon. Thus, this method is expensive. In assembling a large number of ceramic layers (e.g., six or more layers), the middle layer of the green ceramic body is still shrinking (i.e., the force is not evenly distributed by applying a release layer at the top and bottom of the green body) The force between the top and bottom of the green body and that of the middle layer is quite different).

Some modifications of the green ceramic body disclosed in US Pat. No. 5,085,720 were made to provide a suppression layer between the layers of the green ceramic body to prevent shrinkage. This suppression layer remains in the finished product in order to eliminate the disadvantages caused by the removal. However, the suppression layer cannot be a suitable dielectric material, which only thickens the product.

In order to solve the above-mentioned problems, the present invention provides a novel method of reducing the shrinkage of the X and Y axes by reducing the shrinkage of the X and Y axes when simultaneously firing two dielectric materials having different dielectric constants. Multilayer ceramic components and passive devices embedded therein will be developed.

The present invention provides a multilayer ceramic construction comprising at least one dielectric material M ₁ and at least one dielectric material M ₂ . The dielectric materials M ₁ and M ₂ layers prevent shrinkage of the X and Y axes from each other during firing, with passive elements embedded in both of these layers. According to the present invention, each layer of the multilayer ceramic constituent can be utilized as a substrate for embedding passive elements and can prevent other layers with different dielectric constants from shrinking. Thus, the multilayer ceramic construction of the present invention has the advantage that the size can be reduced and the circuit accuracy is excellent.

The object of the present invention

At least one dielectric material M ₁ layer having a dielectric constant K ₁ with at least one passive element embedded therein; And

The dielectric material M, at least one passive component is a buried dielectric constant therein present in the lower portion of the _first layer comprises a K ₂ of at least one dielectric material layer M _2,

K ₁ is different from K ₂ , and the dielectric material M ₁ layer and the dielectric material M ₂ layer prevent shrinkage in the X and Y axes during each firing.

It is an object to provide a multilayer ceramic construction.

The present invention includes at least one dielectric material M ₁ layer having a dielectric constant K ₁ with at least one passive element embedded therein; And

The dielectric material M, at least one passive component is a buried dielectric constant therein present in the lower portion of the _first layer comprises a K ₂ of at least one dielectric material layer M _2,

The K ₁ is different from the K ₂ , and the dielectric material M ₁ layer and the dielectric material M ₂ layer respectively prevent shrinkage in the X and Y axes during firing.

Provide a multilayer ceramic construction.

As shown in FIG. 1, an embodiment of the multilayer ceramic construction 1 of the present invention comprises a plurality of dielectric materials M ₁ having a dielectric constant of K ₁ and a plurality of dielectric materials M having a dielectric constant of K ₂ . _Two layers 12. K ₁ is different from K ₂ , and both the dielectric material M ₁ layer 11 and the dielectric material M ₂ layer 12 can be used as a substrate for embedding the passive element 15. Preferably, a predetermined amount of conductive material is applied to dielectric material M ₁ layer 11 and dielectric material M ₂ layer 12 in a predetermined pattern to form metallization pattern 16. In addition, a number of biases may be drilled through the layers 11 and 12 to be holes passing through the layers 11 and 12. The via conductor 13 may be disposed in this via to electrically connect the passive element 15 and the metallization pattern 16.

The ceramic construction according to a preferred embodiment of the present invention comprises a dielectric layer on top of which the passive element or metallization pattern is not printed on top.

The term " buried passive component " as used herein refers to an electrical component consisting of a dielectric layer and a metallization pattern and / or via conductor and an embedded assembled passive component. For example, manufactured passive devices include capacitors, resistors, and inductors. Specifically, the metallization pattern 16 in the layers 11 and 12 may include the electrodes 11 in multiple opposing directions together with the layers 11 and 12 to form a capacitor. Metallization patterns 16 between layers 11 and 12 form various signal processing devices, such as transfer / receive (T / R) modules and the like.

The metallization pattern 16 and the via conductor 13 preferably comprise high conductivity materials such as gold, silver, copper and alloys thereof, more preferably silver having a melting point of 960 ° C. Therefore, densification of the multilayer ceramic component 1 must be achieved at temperatures below the melting point of the particular conductive material forming the metallization pattern 16. In addition, different circuit designs require materials with different dielectric constants.

Dielectric materials that can be used to prepare the dielectric layer according to the invention are suitable for use as M ₁ and M ₂ . According to a preferred embodiment of the present invention, at least one of the dielectric materials M ₁ and M ₂ comprises ceramic solids and inorganic glass to provide suitable electrical properties.

As used herein, the term "ceramic solids" refers to a composition that is not directly critical if the solids are chemically inert to other materials in the system and have the following physical properties for other components of the dielectric material system: it means. (1) have a sintering temperature of at least the sintering temperature of the inorganic glass; And (2) not to withstand sintering during firing of the present invention. Examples of ceramic solids include inorganic metals, high melting point inorganic solids and high softening point glass. In a more preferred embodiment of the invention, the ceramic comprises barium titanium oxide, barium samarium neodymium titanium oxide, silicon oxide, aluminum oxide, magnesium aluminum silicon oxide and mixtures thereof. In addition, the ceramic solid may be selected in consideration of its dielectric properties and thermal expansion properties. Thus, mixtures of these materials can be selected to suit the thermal expansion properties of any substrate they apply.

The term " inorganic glass " as used herein means an inorganic material that is chemically inert to other raw materials in the system and suitable for the following physical properties. (1) have a sintering temperature of less than or equal to the sintering temperature of the ceramic; And (2) withstand viscous flow sintering at the firing temperature used. Inorganic glasses suitable for the present invention are conventional glasses, in particular crystalline or amorphous glass upon firing. In a more preferred embodiment the inorganic glass is selected from the group consisting of bismuth oxide, tellurium oxide, boron oxide, precursors thereof and mixtures thereof in a content range of about 0.5 to about 98% by weight.

Ceramic solids and inorganic glass are dispersed in a polymeric binder. The polymeric binder is optionally dissolved therein with other materials such as plasticizers, release agents, dispersants, stripping agents, antifoaming agents, and wetting agents. All polymer binders known in the art as being useful for producing low temperature cofired ceramics can be suitably used in the present invention.

Combining ceramic solids with inorganic glass yields a series of materials with different dielectric constants and sintering temperatures. Preferably, the dielectric constant of the dielectric material according to the invention is about 4 to about 2000. In another feature, the sintering temperature of the dielectric material according to the invention is from about 450 ° C. to about 1200 ° C., and more preferably, the sintering temperature for co-firing with silver in ceramic constituents is about 960 ° C. or less.

According to the invention, the dielectric material M ₁ and M ₂ layers are placed adjacent to each other to prevent shrinkage of the X and Y axes. Thus, all contractions occur in the Z direction. The mechanism of inhibiting shrinkage depends on the difference in the sintering temperatures of the dielectric materials M ₁ and M ₂ . For example, if the sintering temperature of dielectric material M ₁ is T ₁ and the sintering temperature of dielectric material M ₂ is T ₂ , then T ₁ is higher than T ₂ . A dielectric material layer M ₂ is started sintered at T _2, by a dielectric material layer M ₁ is not still shrink in ₂ X T and Y-axis shrinkage is suppressed is reduced. At this time, the dielectric material M ₁ layer serves as a suppression layer for suppressing shrinkage of the dielectric material M ₂ layer. When the temperature rises to T ₁ , the dielectric material M ₂ layer completes sintering and no longer shrinks. Thus genetic material M X and Y axis contraction of the _first layer is decreased is suppressed by the dielectric material layer M _2. In order to achieve the effect of preventing shrinkage, T ₁ is preferably at least T ₂ + 50 ° C.

According to the invention, bonding glass can be optionally added between the dielectric material M ₁ layer and the dielectric material M ₂ layer. Bonded glass can be used depending on whether or not a force is applied in the Z direction during firing. The force is sufficient to bring the layers of the multifunctional ceramic component into contact with each other and substantially enough for all shrinkage to occur in the Z direction perpendicular to the ceramic component. That is, the X and Y axes of the ceramic construction do not shrink during firing. If no pressure is applied, a combined glass should be used. The bonded glass may be added directly to the M ₁ and / or M ₂ material or may be present in the form of a bonded glass layer between the dielectric material M ₁ layer and the dielectric material M ₂ layer. The bonded glass layer is prepared by dissolving the glass particles in a suitable solvent such as an ink and printing by coating, spotter dispersion or deposition directly on the dielectric material M ₁ layer and / or dielectric material M ₂ layer.

The present invention provides that (1) all layers of the multilayer ceramic construction can serve as a substrate for embedding passive devices without the need for conventional buffer and / or barrier layers, so that the total size of the ceramic construction is reduced in size to modern electronic products. It can satisfy the requirements of light weight, thinness and small size required. (2) By designing two material layers, M ₁ and M ₂ , which prevent each other from shrinking, shrinkage of the X and Y axes of the ceramic construction according to the invention does not occur. Thus, the accuracy of the circuit designed thereon is greatly improved and thus the yield is increased. (3) Cost savings in the absence of a buffer layer, barrier layer and / or metal supporter. (4) By combining ceramic solid and inorganic glass, a series of materials with various dielectric constants and quality factors can be produced, providing different purpose electrical properties.

The following examples are merely intended to illustrate the invention and are not intended to limit the scope of the invention.

(Examples 1 to 15)

Layer of dielectric material

As shown in Table 1, the raw material components of the ceramic solid and the inorganic glass were mixed, and the polymer slip and the plasticizer were added to prepare a ceramic slip. Ceramic slip was prepared by passing a cast slurry on a blade with a thickness of about 50 μm. The sinter point (T _s ), dielectric constant (K), and quality factor (Q) are also shown in Table 1.

(Example 16)

Shrinkage of Multilayer Ceramic Components

Via layers were drilled and via filled in the dielectric layer according to Example 1 and the Du Pont 951 PT® layer and screen printed. These layers were stacked for 10 minutes at 4000 psi and 60 ° C., and fired. The shrinkage ratios of the X and Y axes of the ceramic component fabricated at various ratios of the dielectric layer according to Example 1 and the Du Pont 951 PT® layer were measured and shown in FIG. 2.

As shown in Figure 2, the shrinkage of the X and Y axes of the multilayer ceramic construction according to the present invention is significantly low, so that the two layers of material can each effectively prevent shrinkage from each other.

While embodiments of the invention have been shown and described, those skilled in the art will be able to make various modifications and improvements. It is not intended to be exhaustive or to limit the invention to the precise forms shown, and all modifications that do not depart from the spirit and scope of the invention are considered to be within the scope defined in the appended claims.

The present invention provides that (1) all layers of the multilayer ceramic construction can serve as a substrate for embedding passive devices without the need for conventional buffer and / or barrier layers, so that the total size of the ceramic construction is reduced in size to modern electronic products. It can satisfy the requirements of light weight, thinness and small size required. (2) By designing two material layers, M ₁ and M ₂ , which prevent each other from shrinking, shrinkage of the X and Y axes of the ceramic construction according to the invention does not occur. Thus, the accuracy of the circuit designed thereon is greatly improved and thus the yield is increased. (3) The cost is reduced in that there is no buffer layer, barrier layer and / or metal supporter. (4) By combining ceramic solid and inorganic glass, a series of materials with various dielectric constants and quality factors can be produced and provided for different electrical properties.

Claims (18)

At least one dielectric material M ₁ layer having a dielectric constant K ₁ and a sintering temperature T ₁ with at least one passive element embedded therein; And The dielectric material M, at least one passive component is a buried dielectric constant K ₂ and the sintering temperature on the inside of which exists in the lower portion of the _first layer is comprises at least one dielectric material layer is an M ₂ T _2, Wherein K ₁ is different than the _{K 2, T 1> T 2} + 50 ℃ , and the shrinkage in the X and Y axes during the sintering of the dielectric material M ₁ layer is prevented by the dielectric material M ₂ layer, a dielectric material M ₂ layer Shrinkage in the X and Y axes during sintering of is prevented by the dielectric material M ₁ layer Multilayer ceramic construction. The method of claim 1, Wherein the K ₁ and K _{2 range} from about 4 to about 2000. The method of claim 1, Wherein at least one of M ₁ and M ₂ comprises a ceramic solid and an inorganic glass. The method of claim 3, Wherein said ceramic solid is selected from the group consisting of inorganic metals, high melting point inorganic solids and high softening point glass. The method of claim 4, wherein Wherein said ceramic solid is selected from the group consisting of barium titanium oxide, barium samarium neodymium titanium oxide, silicon oxide, aluminum oxide, magnesium aluminum silicon oxide, and mixtures thereof. The method of claim 3, Wherein said inorganic glass is selected from the group consisting of bismuth oxide, tellurium oxide, boron oxide, precursors thereof and mixtures thereof. The method of claim 3, The multilayer ceramic construct having an inorganic glass content of about 0.5 to about 98 weight percent. delete delete The method of claim 1, When sintered in the dielectric material M ₂ layer is T _2, X and Y-axis shrinkage if suppressed by the dielectric material M ₁ layer that is not contracted in the T ₂ is, dielectric material M ₁ layer is sintered at T _1, X And the contraction of the Y-axis is a multilayer ceramic composition in which the shrinkage is suppressed by the dielectric material M ₂ layer. The method of claim 1, The multilayer ceramic construction wherein T ₁ and T ₂ are from about 450 ° C. to about 1200 ° C. The method of claim 11, T ₁ and T ₂ are multilayer ceramic constructs of about 960 ° C. or less. The method of claim 1, And the buried passive device comprises a metallization pattern printed on at least one dielectric material M ₁ layer and at least one dielectric material M ₂ layer. The method of claim 13, And the metallization pattern comprises a plurality of opposing electrodes in the layer of dielectric material. The method of claim 13, And a via conductor penetrating the dielectric material layer to electrically connect the buried passive device and the metallization pattern. The method of claim 1, And wherein the embedded passive element comprises a fabricated passive element. The method of claim 1, And the embedded passive component is selected from the group consisting of capacitors, resistors, and inductors. The method of claim 1, A multilayer ceramic construction further comprising a dielectric layer on top.

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