JPH0213955B2 - - Google Patents

Description

[Detailed description of the invention]

``Industrial Application Field'' The present invention relates to a hybrid substrate used for mounting integrated circuits and the like, and a method for manufacturing the same. "Prior Art" Generally, this type of hybrid board has a ceramic base, element patterns such as resistors and capacitors formed on the base, and conductor patterns for electrically connecting these element patterns to each other. There is. BACKGROUND OF THE INVENTION As consumer and industrial equipment becomes lighter, thinner, and smaller, there is an extremely strong demand for further miniaturization and cost reduction for hybrid substrates that support semiconductor integrated circuits. In order to meet such demands, methods of printing patterns on both sides of a ceramic substrate or methods of dispersing each pattern in multiple layers have been considered. In order to apply these methods, techniques for forming through holes in ceramic substrates with high precision and techniques for printing precise patterns are essential. However, it is extremely difficult to form fine through holes with high density and high reliability. For example, conventionally, after forming through holes in a fired ceramic substrate by laser or ultrasonic processing, Ag-Pd for conductor patterns is formed.
A method of filling through holes with paste has been used, but with this method, it is very difficult to form fine through holes at a high density, and the cost is also very high. On the other hand, another method is used in which through holes are formed in an alumina green sheet, then fired, and then filled with Ag-Pd paste by printing. Normally, alumina green sheets are fired at a high temperature of 1600°C. Therefore,
The fired alumina substrate shrinks significantly compared to the green sheet, and also has large variations due to firing. As a result, the variation in through-holes in the fired substrate is about ±0.8%, and when trying to form through-holes as small as 100 to 200 microns in diameter, the through-hole position is determined by the printing of the through-hole conductor (Ag-Pd). A problem arises in that it is removed from its position. Further, if the through hole position changes from the printing position, the through hole may not be sufficiently filled with the conductor. Furthermore, since hybrid substrates are manufactured by repeated firing, even if the through holes are sufficiently filled with conductors, only the conductor, Ag-Pd, will shrink during firing, causing the alumina to shrink. Since the through-hole portion does not shrink, there is a problem in that the shrinkage rate mismatch occurs and cracks occur in the through-hole conductor portion. Furthermore, it is difficult to form fine patterns on fired ceramic substrates by printing methods. This is because even if you try to print a fine pattern on a fired ceramic substrate using paste, etc., the solvent will not penetrate into the substrate and will bleed, so if a pattern of 200 microns or less is drawn, the patterns will be damaged by mechanical and electrical interference. This is because they cannot be separated. There is also a method of dispersing patterns into multiple layers.
Since there is no insulating glass that insulates between each pattern in terms of reliability and softening temperature, it is difficult to put this into practical use. As mentioned above, there are various problems with through-hole formation and multilayering, so hybrid substrates that do not use through-holes and have a pattern formed only on one surface are often used. In a hybrid board on which conductor patterns and element patterns such as resistors and capacitors are arranged on the surface, when a voltage is applied to the patterns, a phenomenon called migration occurs, causing the electrical characteristics of each pattern to deviate from the design values. It may change. Therefore, for patterns that require precision, it is desirable to suppress migration as much as possible. ``Object of the Invention'' An object of the present invention is to provide a method for manufacturing a hybrid substrate that allows through-holes to be formed with high precision and high density. Another object of the present invention is to provide a method for manufacturing a hybrid substrate capable of forming fine patterns. Still another object of the present invention is to provide a method for manufacturing a hybrid substrate that can easily be multilayered. Another object of the present invention is to provide a method for manufacturing a hybrid substrate that is less affected by migration. Still another object of the present invention is to provide a compact and inexpensive hybrid substrate. Another object of the present invention is to provide a hybrid substrate in which through holes and patterns are formed with high precision and high density. "Structure of the Invention" According to the present invention, _{an amorphous glass phase containing CaO, Al2O3, and SiO2 , an oxide} phase containing _Al2O3 ,
a ceramic layer having a partially crystalline phase containing anorthite generated at the interface between the amorphous glass phase and the oxide phase; a conductor pattern formed on the ceramic layer; A hybrid substrate is obtained which is characterized in that it has associated device patterns. According to the present invention, the steps include: preparing a ceramic green sheet made by mixing CaO-Al ₂ O ₃ -SiO _2- based glass powder and Al ₂ O ₃ powder; and forming a first pattern on the green sheet. a first pattern generation step of forming a first pattern; a firing step of simultaneously firing the green sheet and the first pattern at a temperature range of 800 to 1000°C to produce a fired substrate;
A method for manufacturing a hybrid substrate is obtained, which comprises a second pattern generation step of forming a second pattern electrically related to the first pattern on the fired substrate. According to the present invention, there is provided a method for manufacturing a hybrid substrate in which a through hole and a first pattern are formed on a green sheet, and then firing is performed to form a fired substrate, and then a second pattern is formed on the fired substrate. It will be done. In addition, in the present invention, as the ceramic material forming the green sheet,
A ceramic material is used that can be fired at a temperature of 100% and has a shrinkage rate substantially equal to that of the conductive material (Ag-Pd). Furthermore, in the case of multi-layering, green sheets with the first pattern formed thereon are laminated and fired at the above-mentioned temperature. In this case, patterns that do not need to suppress migration are arranged on the surface, and patterns that need to suppress migration are arranged inside the substrate to eliminate the effects of migration. "Example" The present invention will be described below with reference to the drawings. Referring to FIG. 1, a hybrid substrate according to one embodiment of the present invention is shown. First, we will explain the method for manufacturing this hybrid substrate. Glass powder _and Al 2 O ₃ powder containing 10-55% CaO, 45-70% SiO ₂ , and 0-30% Al ₂ O ₃ by weight are used. prepare. This glass powder contains 0 to 20 B ₂ O ₃
% may be included. Next, a mixture containing 50-65% by weight of the glass powder and _50-35 % by weight of _Al2O3 powder is formed. This mixture may contain up to 10% impurities. When a mixture with such a composition, that is, ceramic, is fired at 800 to 1000°C, it hardly shrinks until this temperature is reached, remaining porous, and begins to sinter and shrink rapidly around 800 to 1000°C. was confirmed. This is because softening and fusion of the ceramic occurs in the early stage of firing.
On the other hand, in the latter stage of firing, CaO−Al ₂ O ₃ −SiO ₂ −
Partial crystallization of anorthite occurs at the interface between the (B ₂ O ₃ )-based glass and the Al ₂ O ₃ powder, so the fired substrate thus obtained has high strength due to the partial crystallization. It can be fired at a much lower temperature than conventional ceramic plates. In addition, even if the partially crystallized low-temperature fired plate is reheated at 750-1000°C, no deformation occurs at all. That is, one of the features of the present invention is that anorthite, which is a partial crystal, is precipitated at the interface of two phases of amorphous glass and alumina through softening and fusion. In the present invention, partially crystalline anorthite is generated at the interface between amorphous glass and alumina due to softening and fusion of the ceramic in the early stage of firing of the green sheet. Even if this occurs, the green sheet will not warp because the fired substrate will be placed flat against the setter (base) due to the softened amorphous glass or alumina. In other words, in the present invention, by firing at a temperature above the softening point (800 to 1000°C), flatness is achieved by utilizing softening and fusion in the early stage of firing, and non-flatness is achieved in the late stage of firing. By utilizing the partial crystallization of anorthite precipitated at the interface between two types of phases, crystalline glass and alumina, it is possible to improve physical strength that can withstand reheating. To repeat, at the initial stage of firing, the amorphous glass is partially crystallized but molten, so the fired substrate is always placed flat against the setter plane, resulting in excellent flatness. Demonstrate your sexuality. Even when reheating (750°C to 1000°C) after firing, deformation is prevented because the physical strength is increased due to partial crystallization of anorthite. Furthermore, it was confirmed that this low-temperature fired plate had a lower dielectric constant and coefficient of thermal expansion than conventional plates. When manufacturing the hybrid substrate shown in FIG. 1, through holes 10 are formed in the ceramic green sheet described above. Through holes 10 having a diameter of 200 microns or less can be formed in the green sheet with high precision and high density. Next, a conductor (for example, Ag-Pd) pattern 11 is placed on the green sheet.
is formed by a printing method. On the green sheet,
Because the solvent penetrates and does not bleed, fine patterns (200 microns or less) can be formed. next,
The sheet with the conductor thick film pattern formed thereon is dried. In this state, the through hole 10 is completely filled with the conductor as shown in FIG. In FIG. 1, patterns are individually formed on two green sheets. When Ag-Pd is used as the material for forming the conductor pattern 11, the conduction resistance increases as compared to when only Ag is used, depending on the amount of Pd added, but migration becomes less likely to occur depending on the amount of Pd added. . Since fluctuations in the conduction resistance value due to migration are undesirable, the conductor pattern 11a, which is finally located inside the hybrid board,
is preferably made of Ag, and other parts are preferably made of Ag-Pd. Pd addition amount is 20-50% by weight
In this case, the conduction resistance value is about 15 to 65 mΩ/□, which poses no practical problem. In addition, the part that requires high-speed response is placed inside the board, and this part is
It may be formed by. Next, 800 to 1000 dry green sheets
The sheet and conductor patterns 11, 11a at a temperature of ℃
are fired at the same time. Since the contraction rates of the sheet and the conductor patterns 11, 11a during this simultaneous firing are almost the same, no cracks or the like occur in the conductor filled in the through holes. After the simultaneous firing, a Ru-based resistance paste is printed on a predetermined portion of the surface of the fired substrate to form a resistance pattern 12 as an element pattern, and after the formation, it is dried. Subsequently, the resistor pattern 12 is fired at a temperature of 750 to 950°C. This firing is performed in an oxidizing atmosphere. Hereinafter, the conductor pattern 11 and the resistance pattern 12
After covering with the protective film 13, baking is performed. In this state, the resistance pattern 12 is trimmed to make it equal to the designed resistance value. In this way, a hybrid substrate having fine conductor patterns 11, 11a and resistor pattern 12 is obtained. As shown in Figure 1, the hybrid board includes:
The IC chip 14 is mounted and covered with a protective film. Referring to FIG. 2, a hybrid substrate according to another embodiment of the present invention is formed by laminating a larger number of green sheets than in FIG. In this embodiment, among the conductor patterns, an internal pattern 11a located inside the substrate is more complicated than that in FIG. 1. Referring to FIG. 3, a hybrid board according to yet another embodiment of the present invention includes a resistor 15 inside the board. This built-in resistor 15 is formed by printing on a green sheet, but its resistance value varies widely because it cannot be trimmed compared to the resistor 12 formed on the surface of the substrate. Therefore, the built-in resistor 15 is a resistor whose resistance value can be varied. Furthermore, in this embodiment, a capacitor is also built inside the hybrid board. In FIG. 3, a high dielectric constant capacitor and a temperature compensation capacitor are provided as capacitors. The green sheet used in Figures 1 and 2 has a low dielectric constant, so to form a high dielectric constant capacitor, Pb (Fe _2/3 W _1/3 ), Pb (Fe _1/2 Nb _1/2 ) O ₃ etc. may be used. Further, in order to form a temperature compensation capacitor, a mixed material of a dielectric material powder having a negative temperature coefficient of dielectric constant, such as MgTiO ₃ , and the composition glass powder of the present invention may be used. In FIG. 3, thin layers 18 and 19 forming the dielectric of the high-permittivity capacitor and the temperature-compensating capacitor are shown.
are respectively arranged within the hybrid substrate. Specifically, electrodes are provided above and below a green sheet containing the above-mentioned additives according to the required capacity, and these green sheets are sandwiched between other green sheets and fired as a unit. In this case, each thin layer 1
When guard electrodes are provided on both sides of the thin layers 8 and 19, or when the electrodes penetrate through the thin layers 18 and 19, consideration must be given to making holes in the thin layers. Built-in resistor 15 and capacitors 18 and 19 mentioned above
All electrodes are provided on green sheets,
A first pattern is formed. On the other hand, the resistor pattern 12 provided on the substrate surface forms a second pattern. Referring to FIG. 4, a hybrid board according to another embodiment of the present invention includes a conductor pattern 11 and a resistor pattern 1 manufactured in the same manner as in FIG.
In addition to 2, an insulating layer 20 and Cu
It has a conductor pattern 21 formed by. In this way, in addition to stacking green sheets, a hybrid substrate may be formed by stacking green sheets in combination with other insulating layers 20. "Modification of the embodiment" In the embodiment described above, Ag-Pd was used as an example of the material forming the conductor pattern 11, but Au,
Cu, Ni, etc. may also be used. When Cu and Ni are used, air firing cannot be used, and firing must be performed in a neutral to reducing atmosphere. When forming a resistance pattern on a substrate with a co-fired conductor of Cu and Ni, Ni-Cr, Mo-Si, W-Ni, W, SiC
etc., and then calcined in a neutral or reducing atmosphere. Furthermore, the hybrid substrate may be formed not only by stacking a plurality of green sheets, but also by only a single layer of green sheets. "Effects of the Invention" The ceramic used in the present invention not only can be fired at a lower temperature than conventional alumina ceramics, but as shown in Table 1, it has a low dielectric constant, a low coefficient of expansion, and is lightweight.

[Table] As mentioned above, the ceramic according to the present invention has a low dielectric constant, so it can improve high-speed signal response.
Because it has a low expansion coefficient, it enables direct bonding of large LSI chips. Furthermore, in the ceramic according to the present invention, when a resistor is deposited and fired on a fired substrate on which a conductor pattern is co-fired, diffusion from the substrate to the resistor or reaction between the substrate and the resistor is unlikely to occur. Therefore, a resistor having a desired resistance value and temperature coefficient can be formed. Since the low-temperature fired substrate according to the present invention undergoes densification at the initial stage of firing at 800 to 1000°C and at the same time softens for a short time, it is possible to make it conform to the setter within this time. If the setter has a well-polished and smooth surface, a substrate with a surface parallel to this surface can be obtained. This means that a large, smooth substrate can be formed. In this way, for large substrates with smooth surfaces, 10
It was found that printing over a wide area of ~20cm□ was possible. Further, in the present invention, since fine patterns and through holes can be formed, the area of each individual substrate can be reduced. Therefore, a larger number of individual substrates can be obtained from a large substrate than in the past, and mass production becomes possible. By using the manufacturing method according to the present invention, the time from the formation of through holes to the formation of resistors can be reduced to about 1/6 compared to conventional manufacturing methods, and
A hybrid substrate with higher performance and higher density than before can be obtained. This is because during the firing process, low-temperature fired ceramics undergo almost no firing shrinkage up to around 800-1000°C, so even if the temperature is raised at high speed, the binder can be easily removed, resulting in a short time of about 1-2 hours. This is because firing became possible in a short period of time. in this way,
When firing in a short time, a large amount of air may be blown into the binder removal zone of the thick film furnace to quickly dilute the decomposed gas from the binder and discharged from the system through the exhaust port.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figures are a cross-sectional view showing another embodiment of the present invention, FIG. 3 is a cross-sectional view showing still another embodiment of the present invention, and FIG.
The figure is a sectional view showing another embodiment of the present invention. Explanation of symbols, 10: Through hole, 11, 11
a: conductor thick film pattern, 12: resistance pattern, 1
3: Protective film, 14: IC chip, 15: Built-in resistor,
18, 19: thin layer for capacitor, 20: insulator layer, 21: conductor layer.

Claims (1)

[Claims] 1. An amorphous glass phase containing CaO, Al ₂ O ₃ and SiO ₂ , an oxide phase containing Al ₂ O ₃ , and a combination of the amorphous glass phase and the oxide phase. A ceramic layer having a partially crystalline phase containing anorthite generated at an interface, a conductive pattern formed on the ceramic layer, and an element pattern formed so as to be electrically associated with the conductive pattern. A hybrid board featuring: 2. A preparation step of preparing a ceramic green sheet made by mixing CaO- _Al2O3 - _{SiO2 -} based glass powder and _{Al2O3 powder} , and a first step of forming a first pattern on the green sheet. a pattern generation step; the green sheet and the first pattern;
a firing step of producing a fired substrate by simultaneously firing at a temperature range of 800 to 1000°C; and a second pattern forming a second pattern electrically related to the first pattern on the fired substrate. 1. A method for manufacturing a hybrid substrate, the method comprising: a generation step. 3. The method of manufacturing a hybrid substrate according to claim 2, wherein the first pattern forms a conductor, while the second pattern forms an element.