JP4761441B2 - Ceramic package for electronic component storage - Google Patents

Description

  In the present invention, an electronic component is mounted on a cavity portion formed by a bottom plate body and a window frame-shaped frame body, and a metal lid is directly joined to a conductive metal film formed on the upper surface of the frame body. The present invention relates to a ceramic package for storing electronic components for hermetically sealing in a hollow state inside a cavity portion.

  In recent years, ceramic packages for housing electronic components such as semiconductor elements, crystal resonators, and piezoelectric elements have become smaller, more reliable, etc. for devices equipped with electronic components, such as mobile phones and personal computers. In response to demands, there is an urgent need to cope with lightness, thinness, high reliability, and the like. As shown in FIGS. 2A and 2B, a conventional electronic component housing ceramic package 50 corresponding to this is a substantially rectangular ceramic bottom plate 51 in a plan view with high airtight reliability. And a fired body obtained by laminating and firing a plate-like frame body 52 in the shape of a ceramic window frame having an outer periphery substantially the same as the outer periphery of the bottom plate body 51. Conductive patterns such as an electronic component connection pad 53 made of a refractory metal on the upper surface and an external connection terminal bonding pad 54 made of a refractory metal on the lower surface are formed on the bottom plate 51 simultaneously with the ceramic. A conductive metal film 55 is formed on the frame body 52 by screen-printing a conductor pattern over the entire circumference of the upper surface using a conductor paste made of a refractory metal, and then simultaneously firing with ceramic. In the conventional ceramic package 50 for storing electronic parts, the conductor metal film 55 is made thick so that the conductor metal film 55 is prevented from peeling off from the ceramic and the bonding strength with the ceramic is improved. A conductor pattern having a pattern width is screen printed a plurality of times. Alternatively, as shown in FIGS. 3A and 3B, in another conventional electronic component housing ceramic package 50a, the conductive metal film 55a is made thicker and the conductive metal film 55a is peeled off from the ceramic. In order to prevent this and improve the bonding strength with ceramics, conductor patterns with different pattern widths are combined by screen printing.

  The electronic component storage ceramic packages 50 and 50 a have a cavity portion 56 for mounting an electronic component formed by a flat plate upper surface or a stepped upper surface of the bottom plate body 51 and an inner peripheral wall surface of the frame body 52. Yes. It should be noted that the electronic component storage ceramic packages 50 and 50a are provided with an electroplating surface to electrically connect between the conductor patterns formed on the multilayer ceramic layers or on the surfaces of the multilayer conductor patterns. A via 57 formed by providing a through hole in the ceramic and a castellation 58 are formed for coating. In the ceramic packages 50 and 50a for storing electronic components, electronic components (not shown) are mounted in the cavity portion 56, and metal lids (see FIG. 5) are formed on the conductor metal films 55 and 55a formed on the upper surface of the frame body 52. (Not shown) are directly joined by seam welding, laser welding or the like via a joining material, and the electronic component is hermetically sealed in the cavity portion 56 in a hollow state. The electronic component housing ceramic packages 50 and 50a on which the electronic components are mounted are bonded to a board or the like via solder or the like at the external connection terminal bonding pads 54 on the lower surface of the package.

  Here, a method of manufacturing a typical conventional ceramic package 50 for storing electronic components will be described. The bottom plate body 51 constituting the electronic component storing ceramic packages 50 and 50a has vias at predetermined positions to be the individual electronic component storing ceramic packages 50 and 50a of one or a plurality of large ceramic green sheets. Through holes for 57 and castellations 58 are formed. For each ceramic green sheet for the bottom plate 51, a conductive paste made of a refractory metal is used, and the upper surface of the ceramic green sheet that is the uppermost layer is used for the electronic component connection pads 53 for each piece, Conductor pattern printing for the external connection terminal bonding pads 54 for each individual body on the lower surface of the ceramic green sheet as a lower layer, filling of the through holes of each ceramic green sheet for the vias 57, and penetration for the castellation 58 Screen printing for application to the wall surface of the hole is performed. Further, the frame body 52 constituting the electronic component storing ceramic packages 50 and 50a is in a predetermined position to be the individual electronic component storing ceramic packages 50 and 50a of one or more large ceramic green sheets. A through hole for the cavity portion 56 and the via 57 is formed in the through hole. And the through-hole of each ceramic green sheet is filled with the conductor paste for the vias 57. Further, on the upper surface of the ceramic green sheet that is the uppermost layer for the frame body 52, a conductor paste made of a refractory metal is used to print a conductor pattern for the individual conductor metal films 55 and 55a. . In this printing, in order to increase the thickness of the conductor pattern to be the conductor metal film 55, screen printing is performed a plurality of times with a screen plate made of the same conductor pattern. Or, in order to increase the film thickness of the conductor pattern to be the conductor metal film 55a, the screen printing is performed on each screen plate made of conductor patterns having different pattern widths, and the combination is performed.

  Next, the ceramic green sheets for the bottom plate body 51 and the frame body 52 are overlaid and laminated by applying temperature and pressure to form a laminated body. Further, on both sides or one side of the laminate, a dividing groove for dividing the laminate into individual pieces to be the outer periphery of the individual electronic component housing ceramic packages 50 and 50a is formed. Next, the multilayer body is formed into a fired body in which the ceramic green sheet and the conductor pattern are simultaneously fired in a reducing atmosphere to integrate the ceramic and the conductor pattern. Furthermore, a Ni-plated film and an Au-plated film are applied on the conductor pattern exposed on the outer surface of the fired body, and an assembly in which a plurality of pieces of ceramic packages 50 and 50a for storing individual electronic components are arranged in a matrix form. I am making it.

  In a conventional ceramic package for storing electronic components, when the ceramic lid is directly bonded to the conductive metal film on the upper surface of the frame, the upper surface of the frame is inclined to prevent the brazing material from flowing. A structure in which a step is provided and a conductive metal film is formed on the inclined surface or the step has been proposed (see, for example, Patent Document 1). In addition, in a conventional ceramic package for storing electronic parts, a seal ring is joined to a conductive metal film on the upper surface of the frame with a brazing material in order to join a metal lid to the upper surface of the frame via a seal ring. ing. In order to increase the brazing material reservoir and to firmly join the seal ring, this conductor metal film has been proposed in which a partially raised convex portion is formed by a thick film printing method (for example, , See Patent Document 2).

JP 59-17271 A Japanese Patent No. 2889519

However, the conventional ceramic package for storing electronic components as described above has the following problems.
(1) A ceramic package for storing electronic parts, in which the metal conductor film formed on the upper surface of the frame is screen-printed a plurality of times to increase the film thickness, has a bonding strength between the ceramic and the refractory metal constituting the metal conductor film. Although it is possible to prevent peeling of the metal conductor film from the ceramic when the metal lid is joined, the difference in the thermal expansion coefficient between the ceramic and the refractory metal due to the increased volume of the refractory metal As a result, the thermal stress generated from the substrate increases, and the ceramic package warps. In the ceramic package for storing electronic parts in which the warp has occurred, the flatness of the frame cannot be obtained when the metal lid is bonded to the metal conductor film of the frame, and there is a problem in the airtight reliability after bonding. ing.

  (2) When the ceramic lid is joined to the conductive metal film on the upper surface of the frame as disclosed in JP-A-59-17271, the upper surface of the frame is The ceramic package for storing electronic parts, which has an inclined surface or a step on the upper surface and a conductor metal film is formed on the inclined surface or the step, melts a large amount of brazing material at once to braze the inclined surface and the step. It is effective when joining with a pool of materials. However, when joining directly while concentrating and heating the joint part at a temperature higher than the heat resistance temperature of the electronic component, the brazing material flows over the entire circumference. It is difficult to form a brazing material reservoir, and there is a problem in hermetic reliability. In addition, when joining by melting the brazing material at a time, a brazing material having a melting temperature of the brazing material lower than the heat resistance temperature of the electronic component is required, so that the joining strength after joining becomes relatively low, There is a problem in bonding reliability.

  (3) When joining a metal lid to the upper surface of the frame through a seal ring, as disclosed in Japanese Patent No. 2889519, a brazing material reservoir is enlarged in the conductive metal film on the upper surface of the frame. In order to improve the bonding strength, the ceramic package for electronic component storage, in which the convex parts that are partially raised are formed by the thick film printing method, is required to be lighter, thinner, and smaller. There is a limit to miniaturization due to the ring, and there is a problem that further miniaturization is difficult.

  The present invention has been made in view of such circumstances, and the bonding strength between the ceramic and the metal conductor film is high, the warpage of the package is small, the bonding reliability and the airtight reliability after the lid body bonding are high, and An object of the present invention is to provide a ceramic package for storing electronic components, which can cope with light, thin and small packages.

The ceramic package for storing electronic components according to the present invention that meets the above-described object has one or more bottom plate bodies having a substantially rectangular shape and one or more window frame shapes having substantially the same outer periphery as the outer periphery of the bottom plate body. It consists of a ceramic fired body integrated with a plate-shaped frame, and after electronic parts are mounted on the cavity formed by the upper surface of the bottom plate and the inner peripheral wall surface of the frame, a metal lid is placed on the upper surface of the frame A ceramic for housing electronic parts having a conductive metal film for directly joining the body through a bonding material at a temperature higher than the heat-resistant temperature of the electronic part, while partially heating the joint part continuously and intensively without using a seal ring In the package, the conductive metal film is partially formed with respect to the length direction and the width direction of the frame body at the four corners of the frame body, and the first conductive metal film formed over the entire upper surface of the frame body. Made of a second conductive metal film In both cases, the conductive metal film at the four corners consists of a thick conductive metal film whose thickness is increased by overlapping the first conductive metal film and the second conductive metal film, and the surface of the thick conductive metal film. Is substantially flush with the surface of the other conductive metal film.

The ceramic package for storing electronic components according to claim 1, wherein a conductive metal film for directly joining a metal lid without a seal ring is formed over the entire circumference of the upper surface of the frame. And a second conductor metal film partially formed with respect to the length direction and width direction of the frame body at the four corner corner portions of the frame body, and the conductor metal film at the four corner corner portions has a film thickness. The thick conductor metal film is formed by overlapping the first conductor metal film and the second conductor metal film, and the surface of the thick conductor metal film is substantially flush with the surfaces of the other conductor metal films. Therefore, the thick conductor metal film formed partially suppresses the increase in volume of the refractory metal, suppresses the thermal stress generated from the difference in thermal expansion coefficient between the ceramic and the refractory metal, and reduces the warpage of the ceramic package. While preventing metal conductor film It is possible to prevent peeling from Mick. In addition, direct bonding that does not involve a seal ring while partly and continuously heating the joint part at a temperature higher than the heat resistance temperature of the electronic component makes the entire surface of the conductor metal film substantially flush, This can be easily performed using a brazing material having a high melting temperature, and a package having high bonding reliability and airtight reliability can be obtained. Further, since the package does not use a seal ring, the package can be made lighter, thinner, and smaller, and the electronic device can be reduced in size.

Subsequently, the best mode for carrying out the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.
Here, FIGS. 1A and 1B are a plan view and an AA ′ line enlarged vertical sectional view of a ceramic package for storing electronic components according to an embodiment of the present invention, respectively.

  As shown in FIGS. 1A and 1B, a ceramic package 10 for storing electronic components according to an embodiment of the present invention has a flat plate shape in which one or a plurality (two in FIG. 1) are stacked, or The bottom plate body 11 is made of a substantially rectangular ceramic having a plurality of sheets whose upper surfaces are stepped, and one or a plurality of (two in FIG. 1) window frame shapes having the same outer periphery as the outer periphery of the bottom plate body 11. The ceramic plate-shaped frame 12 is laminated and fired to form a ceramic fired body in which the ceramic and the conductor pattern are integrated. In the ceramic package 10 for storing electronic components, electronic components (not shown) such as a semiconductor element, a crystal resonator, and a piezoelectric element are formed in a cavity portion 13 formed by the upper surface of the bottom plate body 11 and the inner peripheral wall surface of the frame body 12. It can be installed. On the upper surface of the bottom plate body 11 of the ceramic package 10 for storing electronic components, a conductive pattern such as an electronic component connection pad 14 made of a refractory metal for electrically connecting the electronic components is formed by simultaneous firing with the ceramic. Has been. Further, the lower surface of the bottom plate 11 of the ceramic package 10 for storing electronic components is provided with a conductor wiring pattern 15 formed between ceramic layers, vias 16 and castellations 17 for connecting the layers. Conductive patterns such as external connection terminal bonding pads 18 made of a refractory metal that are electrically connected to the electronic component connection pads 14 and bonded to a board or the like to be electrically connected to the outside are simultaneously fired with the ceramic. Is formed.

Further, on the upper surface of the frame body 12 of the ceramic package 10 for storing electronic components, after mounting the electronic components, a metal lid 19 is bonded to the cavity portion 13 in an airtight manner in a hollow state. A conductor pattern of the conductor metal film 20 for directly joining to the conductor metal film 20 instead of the seal ring by seam welding, laser welding, or the like is formed by simultaneous firing with the ceramic. The conductive metal film 20 formed on the upper surface of the frame body 12 was mounted by mounting an electronic component on the cavity portion 13 and then mounting a metal lid body 19 with a brazing material through a brazing material. The joint is partially and concentratedly heated at a temperature higher than the heat resistance temperature of the electronic component, and the metal lid 19 is directly bonded without the influence of temperature on the electronic component without a strong seal ring. By doing so, it is provided in order to form the ceramic package 10 for housing an electronic component, which has high joining reliability and can cope with lightness, thinness and miniaturization with high airtightness reliability of the electronic component.

  The conductor metal film 20 is formed with respect to the length direction and the width direction of the first conductor metal film 21 formed over the entire circumference of the upper surface of the frame body 12 and the frame body 12 at the four corners of the frame body 12. The second conductive metal film 22 is partially formed. The conductor metal film 20 at the four corners is formed as a thick conductor metal film 23 whose thickness is increased by overlapping the first conductor metal film 21 and the second conductor metal film 22. Moreover, the surface of each thick film conductor metal film 23 is substantially flush with the surface of the other conductor metal film 20.

  In the electronic component housing ceramic package 10, when the ceramic upper surface of the frame 12 and the conductor metal film 20 are joined, the thickness of the conductor metal film 20 at the four corners of the frame 12 where stress is concentrated is increased. The thick conductor metal film 23 can be firmly bonded, and the conductor metal film 20 can be prevented from peeling off from the ceramic. In addition, the ceramic package 10 for storing electronic components is formed by suppressing the film thickness except the thick film conductor metal film 23 at the four corners to be thin, and the thermal expansion of the ceramic and the refractory metal constituting the conductor metal film 20. Warpage that occurs due to the difference in coefficients can be prevented. Furthermore, in the ceramic package 10 for storing electronic components, the surface of the conductor metal film 20 that covers the entire circumference of the upper surface of the frame body 12 including the thick film conductor metal film 23 is substantially the same flat surface, and is higher than the heat resistance temperature of the electronic component. It is possible to easily improve the bonding strength and improve the airtight reliability without deteriorating the electronic components by joining the joints while being heated partially and continuously at a temperature.

  The electronic component storage ceramic package 10 is provided with an electroplating film on the surface of each conductor pattern exposed on the surface in order to electrically connect between the conductor patterns formed on the multilayer ceramics. In order to perform this, a conductive wiring pattern for plating (not shown), a via 16 formed by providing a hole in a ceramic, and a castellation 17 are formed. Further, the through-hole conductor film formed on the outer peripheral side surface of the ceramic that is the castellation 17 is connected to the external connection terminal bonding pad 18, and the external connection terminal bonding pad 18 is bonded to a board or the like via solder or the like. Sometimes used to form a meniscus that is firmly bonded to a board or the like. Further, the ceramic package 10 for storing electronic components has the conductive metal film 20 and the metal lid 19 bonded thereto connected to one of the external connection terminal bonding pads 18 and the conductive metal film 20 in an electrically conductive state. It can also be used as a ground for electrical circuits. In this electronic component housing ceramic package 10, an electronic component is mounted in the cavity portion 13, and a metal lid 19 is directly bonded to the conductor metal film 20 formed on the upper surface of the frame 12 via a bonding material. The electronic component is hermetically sealed in the cavity portion 13 in a hollow state. The electronic component housing ceramic package 10 on which the electronic components are mounted is bonded to a board or the like via solder or the like at the external connection terminal bonding pads 18 on the lower surface of the package.

  Here, the manufacturing method of the ceramic package 10 for electronic component accommodation which concerns on one embodiment of this invention is demonstrated easily. The ceramic package 10 for storing electronic components is usually a plate-like frame body having one or more ceramic green sheets in which a plurality of bottom plate bodies 11 before firing are arranged in a matrix and a plurality of window frame shapes before firing. One or a plurality of ceramic green sheets 12 arranged in a matrix are laminated and fired. The ceramic package 10 for storing electronic components is manufactured such that when divided from a large number of pieces into individual pieces, a cavity portion 13 for mounting electronic components is formed at the center of each piece. is doing. The ceramic green sheet for constituting the ceramic package 10 for storing electronic parts includes, for example, alumina, aluminum nitride, low-temperature fired ceramic, etc. as a ceramic base material, but the material is not particularly limited. . For example, when using alumina as the ceramic substrate, first, a powder obtained by adding an appropriate amount of a sintering aid such as magnesia, silica, calcia to aluminum oxide powder, a plasticizer such as dioctiphthalate, an acrylic resin, etc. And a solvent such as toluene, xylene, alcohols, etc. are added, kneaded sufficiently and defoamed to prepare a slurry having a viscosity of 2000 to 40000 cps, and fired by a doctor blade method or the like to have a desired thickness, for example, 0. After drying into a sheet shape so as to be 12 mm, it is cut into a rectangular shape having a desired size.

  One or more ceramic green sheets for the bottom plate 11 are punched into a through hole for forming a castellation 17 and a through hole for forming a via 16 using a drill machine, a punching machine, a mold, or the like. Alternatively, it is provided by drilling by laser processing using laser light. Then, for example, a conductive paste made of a refractory metal such as tungsten (W) or molybdenum (Mo) is applied to the through hole for the castellation 17 of the predetermined ceramic green sheet by screen printing on the wall surface of the through hole. is doing. Further, the through hole for the via 16 is filled by screen printing using a conductive paste made of a refractory metal similar to the above. Further, on the upper surface of the ceramic green sheet that is the uppermost layer of the ceramic green sheet for the bottom plate 11, for example, a conductive paste made of a refractory metal similar to the above is used for electrical connection with an electronic component. An electronic component connection pad conductor pattern for the electronic component connection pad 14 is formed. When the bottom plate 11 is composed of a plurality of sheets, a conductor pattern for the conductor wiring pattern 15 and the like are formed on the surface of the ceramic green sheet as an intermediate layer by screen printing. The lower surface of the ceramic green sheet as the lowermost layer for the bottom plate 11 is bonded to a board or the like using, for example, a conductive paste made of a refractory metal similar to the above, and is electrically connected to the outside. The external connection terminal bonding pad conductor pattern for the external connection terminal bonding pad 18 is formed by screen printing.

  On the other hand, one or a plurality of ceramic green sheets for the frame body 12 are provided with a through hole for forming the via 16 and, if necessary, a through hole connected to the castellation 17 for an NC machine, a punching machine, a mold. For example, a punching process using a laser beam or a laser process using a laser beam is used. And the through-hole for via | veer 16 is filled by screen printing using the conductive paste which consists of refractory metals, such as tungsten (W) and molybdenum (Mo), for example. Further, if necessary, the through hole for the castellation 17 is applied to the wall surface of the through hole by screen printing using a conductive paste made of a high melting point metal similar to the above. Furthermore, on the upper surface of the ceramic green sheet that is the uppermost layer of the ceramic green sheet for the frame body 12, for example, a metal lid 19 is interposed via a bonding material using a conductive paste made of a refractory metal similar to the above. A conductor pattern for a conductor metal film is formed by screen printing in order to form a conductor metal film 20 that is directly bonded and hermetically seals the inside of the cavity 13 in a hollow state. The conductor metal film conductor pattern is formed by using the second conductor metal film 22 on a part of the frame body 12 in the length direction and the width direction at the four corners on the upper surface of the frame body 12. The pattern is formed by screen printing. Then, the conductor metal film conductor pattern continues over the entire circumference of the upper surface of the frame body 12 and covers the pattern for the second conductor metal film 22 so that the frame body 12 has a substantially frame width. A pattern for the first conductive metal film 21 is formed by screen printing. In addition, in order to make the surface of the thick conductive metal film 23 substantially the same flat surface as the surface of the other conductive metal film 20, a flat surface is formed after the pattern for the second conductive metal film 22 is screen-printed. The entire surface of the ceramic green sheet may be pressed with a metal mold having a flat surface so that the pattern for the second conductive metal film 22 is pressed into the ceramic green sheet.

  Next, one or a plurality of ceramic green sheets for the frame body 12 are punched by using a NC machine, a punching machine, a die, or the like for a through hole for the cavity portion 13 that becomes the inner peripheral side surface of the frame body 12. Etc. are provided by drilling. Note that the through hole for the cavity portion 13 may be provided by drilling in advance before forming the pattern for the second conductor metal film 22 and the pattern for the first conductor metal film 21.

  Next, one or a plurality of ceramic green sheets for the bottom plate 11 and the frame 12 are stacked and integrated by applying pressure while applying temperature to form a stacked body. Usually, the surface of the portion to be the thick conductor metal film 23 where the pattern for the second conductor metal film 22 and the pattern for the first conductor metal film 21 overlap by pressurization at the time of the lamination. Can be made to be substantially the same flat surface as that of the surface of the other conductor metal film 20. Furthermore, this laminated body has outer side surfaces of the bottom plate body 11 and the frame body 12, and has a cutter blade whose tip is V-shaped on one side or the other side of the laminated body in order to divide into multiple pieces. Dividing grooves are provided by pressing and the like.

  Next, in the laminate, the ceramic green sheet and the conductor pattern are simultaneously fired at about 1600 ° C. in a reducing atmosphere, so that the ceramic green sheet shrinks by about 30%, and the fired in which a large number of individual packages are assembled. Forming the body. In this fired body, an Ni plating film is applied on all conductor patterns exposed on the outer surface, and then an Au plating film is applied so that a large number of individual packages are arranged in a matrix. Is forming. The ceramic package 10 for storing electronic components of each individual piece of the assembly can be formed by being divided by the dividing grooves of the assembly. In this division, electronic components are mounted on each of the electronic package housing ceramic packages 10 in the state of a large number of aggregates, and hermetically sealed with a metal lid 19, and then divided into individual pieces. Alternatively, after the assembly is divided into individual pieces, electronic components are mounted and hermetically sealed with a metal lid 19.

  The ceramic package for electronic component storage according to the present invention mounts an electronic component element such as a semiconductor element or a crystal resonator, and is small and requires high reliability. For example, a cellular phone or a notebook personal computer It can be used by being incorporated in an electronic device such as.

(A), (B) is the top view of the ceramic package for electronic component storage which concerns on one embodiment of this invention, respectively, A-A 'line longitudinal cross-sectional view. (A), (B) is the top view of the conventional ceramic package for electronic component accommodation, and a B-B 'line longitudinal cross-sectional view, respectively. (A), (B) is the top view of the modification of the ceramic package for electronic component accommodation, respectively, and the C-C 'line longitudinal cross-sectional view.

Explanation of symbols

  10: Ceramic package for storing electronic components, 11: Bottom plate, 12: Frame, 13: Cavity, 14: Electronic component connection pad, 15: Conductor wiring pattern, 16: Via, 17: Castration, 18: External connection Terminal bonding pad, 19: metal lid, 20: conductor metal film, 21: first conductor metal film, 22: second conductor metal film, 23: thick film conductor metal film

Claims (1)

It consists of a ceramic fired body in which one or more bottom plate bodies having a substantially rectangular shape and one or more plate-shaped frame bodies having a window frame shape having substantially the same outer periphery as the outer periphery of the bottom plate body are integrated. After the electronic component is mounted on the cavity formed by the upper surface of the bottom plate body and the inner peripheral wall surface of the frame body, a metal lid is attached to the upper surface of the frame body through a bonding material to heat-resistant the electronic component In a ceramic package for storing electronic parts having a conductive metal film for direct bonding without using a seal ring while partially and centrally heating the joint part at a temperature higher than the temperature,
The conductor metal film is partially formed with respect to the length direction and the width direction of the frame body at the first corner of the frame body, and the first conductor metal film formed over the entire circumference of the upper surface of the frame body. A thickness formed of the second conductive metal film to be formed, and the conductive metal film at the four corner portions is thickened by overlapping the first conductive metal film and the second conductive metal film. A ceramic package for storing electronic parts, characterized in that it is made of a film conductor metal film, and the surface of the thick film metal film is substantially flush with the surface of the other conductor metal film.

Images