TWI229351B - Multilayer ceramic composition - Google Patents

Abstract

The present invention provides a multilayer ceramic composition comprising at least one layer of dielectric material M1 and at least one layer of dielectric material M2, wherein passive components are buried in both layers of dielectric material M1 and M2 that prevent each other from shrinkage in the X and Y dimensions during firing. Each layer of the multilayer ceramic composition according to the invention can be used as a substrate for burying the passive component and has the ability to prevent other layer with different dielectric constant from shrinkage. Hence, the multilayer ceramic composition has the advantages of smaller size and a better circuit precision.

Description

1229351

玖 τ (miscellaneous description of the invention: the technical field to which the invention belongs, the prior art, the inner yuan, the embodiment, and the simplified drawings) [Field of the Invention] The present invention relates to a ceramic composition, specifically, a Electron microwave system · Laminated ceramic composition. [Previous technology] In order to meet the requirements for light, thin, and small electronic hand products, interconnecting circuit boards has become necessary. The interconnecting circuit board is an electronic circuit or a sub-system which is electrically or mechanically connected to each other. The sub-system is discarded as several extremely small passive components and a combination of metallization patterns. The passive component and the metallization pattern are physically separated, and are embedded next to each other on a single interconnect circuit board, so that they are connected to each other and / or extend from the interconnect circuit board. Ceramic compositions are now widely used in interconnect circuit boards. In ceramic compositions, complex electronic circuits typically require several insulation_cladding layers to separate the conductive layers. In order to meet the requirements of different dielectric constants for cleaning or embedding passive components and metal patterns, it is necessary to develop a series of dielectric materials with different dielectric constants. For example, the signal processing part of the ceramics composition is better with a low dielectric constant material, which can increase its internal signal speed to increase / decide _ Putian. — And is used as an embedded passive antenna in manufacturing Such as 黾 container, etc., it is better to use high-media Leitang% hanging number material. Passive dielectric elements and metallized patterns interconnect through the dielectric layer.. ^ S ^ The conductive path is called a through hole (vus)-this layer, the structure can make the circuit more compact and less space. The method of multilayer ceramic composition is described in U.S. Patent # 4,654,095, which is hereby incorporated by reference. The laminated Tao Yao composition has been 1229351. Passive components and metallized patterns such as resistors, capacitors or conductors are printed. It interconnects various passive components and metallized patterns with metalized through holes extending through the dielectric layer. The ceramic powder can be densified at a temperature suitable for the use of highly conductive metals such as gold, silver and copper. In particular, densification is at or below 100 ° C to provide a margin of error sufficient to distinguish it from the melting point of gold (106 ° C). The dielectric layers are stacked and pressed together at an appropriate temperature and pressure " and then fired to remove organic substances such as adhesives and plasticizers from the ceramic green body. All ceramics and heterogeneous materials are thus densely sintered. The advantage of this method is that the firing is performed only once, which can save manufacturing time and labor, and limit the diffusion of the movable metal to avoid short circuit between conductive layers. However, co-fired monolithic structures with high-K dielectrics and low-K dielectric materials still have problems; one of the problems is the change in electrical properties, and the other is that shrinkage occurs during firing and causes dislocation. Regarding the change of electrical properties, many conventional assemblies use both low dielectric constant materials and high dielectric constant materials. The low dielectric constant material contains glass, which results in an increase in dielectric constant and loss; the high dielectric constant material contains lead, magnesium, and niobium. However, when the low dielectric material and the high dielectric material are in contact with each other and co-fired at a temperature higher than 800 ° C, a chemical reaction occurs due to diffusion between the interfaces. For this reason, the dielectric constants of both low and high dielectric constant materials are changed, and a dramatic decrease in high dielectric constant materials usually occurs. The insertion of a plurality of buffer layers between low and high dielectric constant materials for electronic packaging is disclosed in US Patent No. 5,7 5 7,6 1 1, where a buffer layer containing 25 to 100% barium compound is used to generate more Difficult chemical diffusion path, which can cause

O: \ 82 \ 82936.DOC 1229351 l_ (3) Provide additional physical barriers during the initial stages of densification. Through-holes can also be formed through the buffer layer for conducting electricity between the passive element portion and the i-numbered processing portion. With glass-forming additives and inorganic fillers, the shrinkage a, thermal expansion, and chemical compatibility of the buffer layer in contact with the high-K dielectric layer of the passive element portion or the low-K dielectric layer of the signal processing portion can be controlled. However, the buffer layer also increases the thickness of the electronic package, so it cannot be used as a good substrate for embedding passive components. -•--Other laminated ceramic green belt structures with different K values are shown in US Patent No. 6,0 5 5, 1 51, which focuses on the inks printed on the green belt at low firing temperature to form the inner layer. Buried components such as capacitors to increase tolerance for highly accurate placement. The capacitor layer is sandwiched between two barium titanate barrier layers having a thickness sufficient to prevent low-fire temperature glass diffusion in the green belt. Furthermore, the laminated ceramic green tape structure is adhered to the metal support structure by the bonding glass to avoid shrinkage. However, the shrinkage rate of the low firing temperature green belt is not the same as that of the metal support substrate, and it needs to be well controlled during firing to avoid cracking. Similarly, the thickness of the laminated ceramic green belt structure cannot be reduced. Regarding the shrinkage part, since the shrinkage of each element is different during sintering, it is difficult to control the firing conditions. Furthermore, when assembling large and complex circuits, misregistration due to uncertainty in the X and Y directions needs to be avoided. A method for reducing shrinkage when firing ceramic green embryos is disclosed in U.S. Patent No. 5,0 8 5,720, in which a release layer is applied to the upper and bottom of the ceramic green embryos to form a "sandwich" structure. During firing and sintering, a unidirectional pressure is applied to the surface of the release layer. The porosity of the release layer provides a way for the volatile components in the ceramic embryo to escape. Since the release layer is in the firing period

O: \ 82 \ 82936.DOC 1229351 (4) does not shrink between, so it can reduce the X and Y shrinkage of ceramic green embryos. On the other hand, the release layer covering both the upper and lower surfaces of the ceramic green body needs to be removed after printing and sintering of the conductor, resistor and capacitor, thus increasing the cost of this method. When manufacturing multi-layer ceramic deformation: layers (such as more than 6 layers), the middle layer of ceramic raw embryos will still shrink due to the uneven force applied to the upper and lower parts of the raw embryos (that is, the upper part of the raw embryos) And the strength of the lower and middle layers are substantially different). U.S. Patent No. 5,0 8 5,720 discloses a slight modification of ceramic green embryos, which includes a shrinkable inhibitor layer between the ceramic green embryo layers and retains the inhibitor layer in the final product to avoid the disadvantages of removal. However, the suppression layer cannot be used as a suitable dielectric material, resulting in increased product thickness. In order to solve the above problems, the present invention develops a novel multilayer ceramic composition, which has the advantages of reducing the size and reducing the temperature when two dielectric materials with different dielectric constants are co-fired and the passive components are embedded therein. X- and Y-direction shrinkage to provide better circuit accuracy. SUMMARY OF THE INVENTION The present invention provides a multilayer ceramic; a composition comprising at least one layer of a dielectric material M! And at least one layer of a dielectric material M2, wherein a passive element is embedded in two layers of the dielectric material M1 and M2, Avoid shrinking in the X and Υ directions when firing. Each layer of the multilayer ceramic composition of the present invention can be used as a substrate for embedding passive components, and can avoid shrinkage of other layers having different dielectric constants. Therefore, the laminated ceramics composition has the advantages of reduced size and better circuit accuracy. An object of the present invention is to provide a laminated ceramic composition, which includes:

O: \ 82 \ 82936.DOC 1229351 (5) l ^ M] at least one layer of a dielectric material having a dielectric constant K1 and at least one embedded passive component therein; and at least one layer having a dielectric constant K2 The dielectric material layer M2 has at least one embedded passive component therein, which is disposed below the dielectric material layer M1; where K1 is different from K2, and the dielectric material layer M1 and the dielectric material layer M2 It is possible to avoid shrinkage of each other in the X and Y directions during sintering. [Embodiment] The present invention provides a multilayer ceramic composition comprising: at least one dielectric material layer M1 having a dielectric constant K1, and having at least one embedded passive element therein; and at least one layer having a dielectric constant K2 The dielectric material layer M2 has at least one embedded passive component therein, which is disposed below the dielectric material layer M1; where Km is different from K2, and the dielectric material layer Mm and the dielectric material layer M2 It is possible to avoid shrinkage of each other in the X and Y directions during sintering. A specific embodiment of the multilayer ceramic composition 1 of the present invention is shown in FIG. 1 and includes a plurality of dielectric material layers M11 having a dielectric constant Km and a plurality of dielectric material layers M2 12 having a dielectric constant K2, wherein Kι is different from K2. Both the dielectric material layer Mm 11 and the dielectric material layer M2 12 can be used as the substrate of the embedded passive element 15. Preferably, the metallization pattern 16 is generated by applying a selected amount of conductive metal on the dielectric material layer M11 and the dielectric material layer M2 12 according to the selected pattern. It is also possible to punch through the layers 1 1 and 12 to form a plurality of through holes, which may be openings through the layers 1 1 and 12, O: \ 82 \ 82936.DOC -10- 1229351 ⑹ through hole conductor 1 3 can be placed in the through hole to electrically connect the passive element 15 and the metallized pattern 16. ‘In a preferred embodiment of the invention, the ceramic composition further includes a dielectric layer overlying one of the passive components or the metallization pattern. As used herein, "embedded passive component" refers to an assembled embedded passive component, or an electronic component made of a dielectric layer and a metallized pattern and / or a via conductor. 6 For example, an assembled passive component Passive components include capacitors, resistors, and inductors. In particular, the metallization pattern 16 in the layer 11 or 12 may include multiple layers of electrodes 14 oriented in opposite directions, which together with the layer 11 or 12 form a capacitor. The metallized patterns 16 between layers 1 1 or 12 may form signal processing devices such as a transmit / receive (T / R) module and the like. The metallization pattern 16 and the via-hole conductor 13 preferably include highly conductive materials such as gold, silver, copper, and alloys thereof, and more preferably includes silver with a melting point of 96 ° C. Therefore, the densification of the laminated ceramic: composition 1 needs to be achieved at a temperature lower than the melting point of the specific conductive material used to form the metallized pattern 16. Furthermore, for circuits of different designs, materials with different dielectric constants are required. The dielectric materials that can be used to make the dielectric layer of the present invention are suitable as M i and M 2. According to a preferred embodiment of the present invention, at least one of the materials M1 and M2 includes ceramic f that provides suitable electrical properties: solid particles and inorganic glass. The "ceramic solid particles" described in this article represent a group of compounds, which is not directly strictly defined, as long as the solid particles are chemically inert to other materials in the system, and have the following physical properties relative to other elements of the dielectric material system, namely O: \ 82 \ 82936.DOC -11-

1229351 ⑺ Can: (1) have a sintering temperature sufficiently higher than the sintering temperature of inorganic glass, and (2) those who do not undergo sintering during firing. Examples of ceramic solid particles include inorganic metals, high-melting inorganic solid particles, and high softening point glass. In a more specific embodiment, the ceramic comprises barium titanium oxide, barium hafnium niobium titanium oxide, silicon oxide, aluminum oxide, magnesium aluminum silicon oxide, and mixtures thereof. Furthermore, the ceramic solid particles can be selected based on both their dielectric and thermal expansion properties. Therefore, a mixture of the above materials can be selected to meet the thermal expansion characteristics of any substrate used. "Inorganic glass" as used herein represents an inorganic material that is chemically inert to other materials in the system and has the following physical properties: (1) has a sintering temperature that is sufficiently lower than that of ceramics, and (2) experiences at the firing temperature Viscosity phase mobile sinterer. The inorganic glass suitable for use in the present invention is generally glass, especially crystallized or non-crystallized glass upon firing. In a more specific embodiment, the inorganic glass is selected from the group consisting of bismuth oxide, tellurium oxide, boron oxide, precursors and mixtures thereof, and the amount is about 0.5 to about 98% by weight. Within range. The ceramic solid particles and the inorganic glass are dispersed in a polymer binder. Other materials such as a plasticizer, a release agent, a dispersant, a release agent, a defoaming agent, and a wetting agent are dissolved in the polymerization adhesive as appropriate. Any polymeric binder known in the art to be suitable for making low temperature co-fired ceramics is suitable for use in the present invention. By combining ceramic solid particles and inorganic glass, a series of materials with different dielectric constants and sintering temperatures can be obtained. Preferably, the dielectric constant of the dielectric material of the present invention is in the range of about 4 to about 2000. On the other hand, the sintering temperature of the dielectric material of the present invention is from about 450 to about 12 0 ° C, and wherein O: \ 82 \ 82936.DOC 12-1229351

More preferably, the sintering temperature is lower than about 960 ° C for co-firing with silver in the ceramic composition. -According to the present invention, the dielectric material layers M1 and m2 are placed in contact with each other to avoid shrinkage in the X, and Y directions, and cause all shrinkages to occur in the z direction. The mechanism to avoid shrinkage depends on the difference in sintering temperature of the materials, materials M1 and M2. For example, the sintering temperature of the dielectric material M! Is Tl, and the sintering degree of the dielectric material m2 is D2, where T! Is greater than τ2. When the dielectric material layer M2 starts to sinter at τ2, its shrinkage in the X and Y directions is suppressed and reduced by the dielectric material layer M i that has not contracted at T2. At this time, the dielectric material layer M1 functions as a suppressing layer to suppress the dielectric material layer M2 from shrinking. When the temperature rises to T1, the 'dielectric material layer M2 has completed and no longer shrinks, so the shrinkage of the dielectric material layer M1 in the X and Υ directions is suppressed by the dielectric material layer M2 and reduced. Preferably, T! Is greater than τ 2 + 50 ° C to achieve a better effect of avoiding shrinkage. According to the present invention, a bonding glass may be added between the dielectric material layer M1 and the dielectric material layer m2. Regardless of whether external force is applied in the Z direction during sintering, bonded glass can be used. This force is sufficient to bring the layers of the laminated ceramic composition into contact with each other and substantially cause all shrinkage to occur in the Z direction of the vertical ceramic composition, that is, the X and Y directions of the ceramic composition do not shrink during firing. Adhesive breaking glass is used when no pressure is applied. The bonding glass may be directly added to the Mm and / or m2 material, or a bonding glass layer may be formed between the dielectric material layer M! And the dielectric material layer M2. The bonding glass layer is prepared by dissolving glass particles in a suitable solvent such as ink, and printing on the dielectric material layer M i and / or the dielectric by direct coating, dot deposition or vapor deposition.

O: \ 82 \ 82936.DOC

1229351 (9) On the electric material layer m2. The invention has many advantages: (1) due to laminated ceramics; each layer of the composition can be used as a substrate for embedding passive components without the need for a buffer layer and / or a barrier layer of the prior art. The size can be considerably reduced to meet the requirements of light, thin and small products of modern electronic products; (2) the design of the two material layers M 1 and M 2 to avoid shrinking with each other, X and X of the ceramic composition of the present invention The 'direction Y' does not shrink. Therefore, the accuracy of the circuit designed on it can be improved considerably, and the yield is improved; (3) From the viewpoint of the lack of a buffer layer, a barrier layer and / or a metal support, the cost can be reduced; (4) by combining Ceramic solid particles and inorganic glass can be made into a series of materials with varying dielectric constants and quality factors, so they can be used for electrical properties of different purposes. The following examples are for illustrative purposes only and are not intended to limit the invention. Examples 1 to 15: Dielectric material layer The material components of the ceramic solid particulate inorganic glass shown in Table 1 were mixed, and then a polymer binder and a plasticizer were added to form a ceramic bar. The ceramic strip is formed by casting the casting slurry under a blade having a thickness of about 50 microns. The sintering temperature (Ts), dielectric constant (K) and quality factor (Q) are also described in Table 1. Table 1: Examples of inorganic glass (B) ceramic solid particles (c) B / C Ts KQ 1 87% Bi203-3% B203-10% Te02 Ba (SmNd) 2Ti5〇i4 30/70 745 55 450 2 87% Bi2 〇3-3% B2O3-10% Te〇2 Ba (SmNd) 2Ti5〇i4 50/50 632 40 320 3 87% Bi2〇3-3% B2O3-10% Te〇2 Ba (SmNd) 2Ti5〇i4 70 / 30 545 38 ISO 4 65% Bi203-2.5% B2 03-32.5% Te02 Ba (SmNd) 2Ti5〇i4 65/35 635 37 250 5. 65% Bi203-2.5% B2 03-32.5% Te02 Ba (SmNd) 2Ti5014 50/50 666 46 340 6 16% Bi203-14% B2O3-70% TeO2 Ba (SmNd) 2Ti5〇i4 20/80 680 65 421 O: \ 82 \ 82936.DOC 14 1229351 (10) 7 16% Bi2〇 3-14% B2〇3-70% TeO2 Ba (SmNd) 2Ti5〇i4 30/701 577 I 60 1350 8 87% Bi203-3% B2〇3-l0% Te02 BaTi03 65/35 677 850 150 9 87% Bi2〇3-3% B2O3-10% TeO2 BaTi03 50/50 760 1100 175 10 65% Bi203-2.5% B203-32.5% Te〇2 BaTi03 40/60 938 1500 230 11 65% Bi203-2.5% B203-32.5% Te02 BaTi03 65/35 834 700 145 12 65% Bi203-2.5% B2〇3-32.5% Te02 Si02 65/35 630 4 225 13 65% Bi203-2.5% B2 03-32.5% Te02 AI2O3 65/35 710 5 350 14 65% Bi203-2.5 ° / 〇B2〇3-32.5% Te02 3Al203-2Si02 65/35 675 4 320 15 65% B i203-2.5% B203-32.5% Te02 Mg2Al4Sl50i8 65/35 665 3.5 250 Example 16: Shrinkage of laminated ceramic composition The dielectric layer and Du Pont 95 1 PT® layer of Example 1 were punched through holes , Filling and screen printing circuits. The layers were stacked and laminated at 4,000 p s i and 60 ° C for 10 minutes and fired. The shrinkage ratios in the X and Y directions of the ceramic composition of Example 1 dielectric layer and Du Pont 951 PT⑧ layer with different ratios were measured. The results are shown in FIG. 2. As shown in FIG. 2, the shrinkage ratios of the laminated ceramic composition of the present invention in the X and γ directions are relatively low, indicating that the two layers of materials can effectively avoid shrinking with each other. Although the present invention has been illustrated and described, those skilled in the art can make various modifications and improvements. It should be understood that the present invention is not limited to the specific forms described, and all modifications that do not depart from the spirit and scope of the invention are within the scope defined by the scope of the patent application. [Brief description of the drawings] FIG. 1 illustrates a schematic cross-sectional view of a specific embodiment of a laminated ceramic composition of the present invention. Figure 2 illustrates the measured shrinkage of O: \ 82 \ 82936.DOC -15-1229351 _ do when co-firing different thickness ratios of M1 and M2 layers, where M1 represents the dielectric material of Example 1, and M2 represents Common low temperature co-sintered ceramics (product name < Du Pont 95 1 PT⑧). [Simple description of element symbols] I Multilayer ceramic composition II Dielectric material layer M i 12 Dielectric material layer M2 13 Conductor 14 Electrode 1 5 Passive element 16 Metallized pattern, O: \ 82 \ 82936.DOC 16-

Claims (1)

1229351 Patent application scope 1. A laminated ceramic: a composition comprising: at least one layer of a dielectric material layer having a dielectric constant Km, and having at least one embedded passive element therein; and at least one layer having a dielectric The dielectric material layer M2 with a constant κ2, and has at least one embedded passive element therein, which is disposed below the dielectric material layer M1; where Km is different from K2, and the dielectric material layer Mm and the dielectric The electrical material layer M2 can avoid shrinking with each other in the X and Y directions during firing. 2. The composition according to item 1 of the patent application range, wherein K1 and K2 are between 4 and 2000. 3. The composition according to item 1 of the patent application scope, wherein at least one of M1 and M2 includes ceramic solid particles and inorganic glass. 4. The composition according to item 3 of the patent application range, wherein the ceramic solid particles are selected from the group consisting of inorganic metals, melting solid inorganic particles and southern softening point glass. 5. The composition according to item 4 of the application, wherein the ceramic solid particles are selected from the group consisting of barium titanium oxide, barium hafnium niobium titanium oxide, silicon oxide, aluminum oxide, magnesium aluminum silicon oxide, and mixtures thereof. Into groups. 6. The composition according to item 3 of the scope of patent application, wherein the inorganic glass is selected from the group consisting of bismuth oxide, tellurium oxide, boron oxide, its precursor, and a mixture of 1229351. 7. The composition according to item 3 of the patent application / wherein the amount of the inorganic glass is between 0.5 and 98% by weight. 8. The composition according to item 1 of the scope of patent application, wherein the sintering temperature of the dielectric material M! Is ir! And the sintering temperature of the dielectric material M2 is T2, and Ti is greater than T2 0. * 9 · As stated in the application The composition of item 8 of the patent, wherein +. 10. The composition of the scope of patent application item 8, wherein when the dielectric material layer M2 is sintered at T2, the shrinkage in the X and Y directions is suppressed by the dielectric material layer M1 that has not contracted at T2, and when the dielectric material When Mm sinters to h, its shrinkage in the X and Y directions is suppressed by the dielectric material layer M2 that has completed shrinkage. 11. If the composition of the scope of application for item 8 of the patent, wherein Ti and T2 are between 45 ° C and 1200 ° C. 12. The composition according to item 11 of the patent application scope, in which Ti and T2 are lower than 9 60 ° C. 13. The composition as claimed in claim 1, wherein the embedded passive cell includes a metallized pattern printed on at least one dielectric material layer M1 and at least one dielectric material layer M2. 14. The composition according to item 13 of the patent application scope, wherein the metallization pattern comprises a plurality of opposing electrodes in the dielectric material layer. O: \ 82 \ 82936.DOC 1229351 15. The composition according to item 13 of the scope of patent application, further comprising electrically connecting the embedded passive element and the metallized pattern through the through-hole conductor of the dielectric material layer. 16. The composition of claim 1 in which the embedded passive component includes a passive component that has been assembled. 17. The composition according to claim 1 in which the embedded passive component is selected from the group consisting of a capacitor, a resistor and an inductor. 18. The composition according to item 1 of the patent application scope, further comprising a covering dielectric layer. O: \ 82 \ 82936.DOC