package

Abstract

To provide a package capable of suppressing a decrease in airtightness. [Solution] The frame portion (120) is made of ceramic and has a first surface (SF1) and a second surface (SF2). The second surface (SF2) has an inner edge surrounding the cavity (CV) and an outer edge (EO) surrounding the inner edge. The substrate portion (110) is made of ceramic and has a third surface (SF3) having a portion supporting the second surface (SF2) of the frame portion (120) and a portion facing the cavity (CV). The electrode layer (200) is provided on the third surface (SF3) of the substrate portion (110). The via electrode (510) has an end surface (SFA) with a diameter (DA) on the first surface (SF1) and a bottom surface (SFB) that contacts the electrode layer (200) on the second surface (SF2) and has a diameter (DB) smaller than the diameter (DA). In a plan view, the bottom surface (SFB) of the via electrode has a minimum dimension (LI) from the inner edge of the second surface (SF2) of the frame portion (120) and a minimum dimension (LO) from the outer edge (EO) of the second surface (SF2) of the frame portion (120), where LO > LI.

Description

[Technical Field]

[0001] The present invention relates to a package, and more particularly to a ceramic package having a frame portion penetrated by via electrodes. [Background technology]

[0002] Packages for quartz crystal resonators are known as ceramic components manufactured using ceramic green sheets. A typical quartz crystal resonator includes a quartz crystal blank, a package with a cavity that houses the quartz crystal blank, and a lid for sealing the cavity. The package includes a substrate that forms the bottom of the cavity, a frame that surrounds the cavity, and a metallized layer provided on the frame. The lid is bonded to the metallized layer using a bonding material (typically, a brazing material).

[0003] The metallized layer on the frame of a package is usually electrically shorted to a ground potential electrode pad. This electrical path can typically be secured through a via electrode that penetrates the frame. However, as packages become smaller, the width of the frame material (the dimension between the inner and outer wall surfaces of the frame) has become smaller, making it difficult to form fine via electrodes accordingly. Specifically, it has become difficult to form fine via holes for fine via electrodes in a green sheet that will become the frame after firing. When a pin-shaped mold is used as a typical method for forming via holes, the mechanical strength of the pins tends to be insufficient when the pin shape is reduced to achieve finer via holes. Therefore, according to a technology disclosed in, for example, Japanese Patent Laid-Open Publication No. 2007-27592, a castellated electrode having a roughly crescent shape is provided on the inner wall surface of the frame instead of a via electrode.

[0004] However, when castellation electrodes are provided on the sidewalls of the cavity instead of via electrodes, as in the technology of the above publication, the brazing material is likely to flow into the cavity along the castellation electrodes during the brazing process. Contact between the flowing brazing material and the crystal blank can adversely affect the performance of the crystal unit. While the adverse effects on mechanical characteristics due to the flowing brazing material are particularly a concern when the element mounted in the package is a crystal blank, they can also occur with other piezoelectric elements. Furthermore, as long as the element mounted in the package is an electrical element, there is concern about adverse effects on electrical characteristics, such as unintended short circuits.

[0005] Japanese Patent Application Laid-Open Publication No. 2009-234074 discloses a method for forming minute through-holes as via holes in a ceramic green sheet using laser processing technology. Specifically, through-holes with diameters of 30 μm to 50 μm are formed in a ceramic green sheet with a thickness of 250 μm or less using an ultraviolet laser. It has been pointed out that when through-holes with a small diameter relative to the thickness are formed by laser processing, the through-holes tend to have a tapered shape. The publication also points out that the tapered shape of the through-holes makes it difficult to fill the through-holes with a conductive paste. Therefore, the technology of the publication studies laser beam irradiation conditions that can achieve a taper ratio of 60% or more. Here, the taper ratio is defined by the taper diameter ratio, with a taper ratio of 100% meaning that the through-hole has no tapered shape, and a smaller taper ratio meaning a more rapid tapered shape. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-27592 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-234074 Summary of the Invention [Problem to be solved by the invention]

[0007] According to the inventors' investigations, if the laser processing technique disclosed in the above publication is simply applied for the purpose of providing a via electrode in the frame of a package, it may be difficult to ensure sufficient airtightness of the cavity. This problem becomes more serious as the width of the frame becomes smaller with the progress of miniaturization of packages.

[0008] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a package that can suppress a decrease in airtightness. [Means for solving the problem]

[0009] a ceramic substrate having a third surface including a portion supporting the second surface of the frame and a portion facing the cavity; an electrode layer provided on the third surface of the substrate; and a via electrode penetrating the frame between the first surface and the second surface; the via electrode having an end surface with a diameter DA on the first surface and a bottom surface with a diameter DB that is smaller than the diameter DA and that contacts the electrode layer on the second surface; and a minimum dimension LI from the inner edge of the second surface of the frame in a plan view and a minimum dimension LO from the outer edge of the second surface of the frame, where LO>LI.

[0010] A second aspect is the package of the first aspect, wherein the diameter DA is 50 μm or less.

[0011] A third aspect is the package of the first or second aspect, wherein the minimum dimension between the inner edge and the outer edge of the second surface of the frame is 200 μm or less.

[0012] A fourth aspect is a package according to any one of the first to third aspects, in which LO≧LI×1.5 is satisfied.

[0013] A fifth aspect is the package of any one of the first to fourth aspects, wherein the via electrode has a diameter of (DA+DB) / 2 or less at a midpoint between the end face and the bottom face in the thickness direction.

[0014] A sixth aspect is the package of any one of the first to fifth aspects, wherein the via electrode has a portion that extends in a tapered shape from the end face in the thickness direction.

[0015] A seventh aspect is the package of the sixth aspect, wherein the tapered shape has a taper angle of 5 degrees or more.

[0016] An eighth aspect is the package of the sixth or seventh aspect, wherein the tapered shape has a thickness that is half or more of the thickness of the frame portion.

[0017] A ninth aspect is a package of any one of the first to eighth aspects, wherein the via electrode has a side surface connecting the end surface and the bottom surface, and the side surface has at least one bending point when viewed in a cross section parallel to the thickness direction.

[0018] A tenth aspect is the package of the ninth aspect, wherein the at least one flex point includes two flex points that flex in opposite directions.

[0019] An eleventh aspect is a package according to any one of the first to tenth aspects, wherein the frame portion has an outer wall surface connecting the first surface and the outer edge of the second surface, and the outer wall surface has an as-fired surface connecting to the first surface and a fracture surface connecting to the second surface.

[0020] A twelfth aspect is a package of any of the first to eleventh aspects, further comprising a metallization layer provided on the first surface of the frame portion and in contact with the end face of the via electrode, the metallization layer being locally thicker at the connection portion with the end face of the via electrode.

[0021] A thirteenth aspect is a package of any of the first to eleventh aspects, further comprising a metallized layer provided on the first surface of the frame portion and in contact with the end face of the via electrode, wherein the first surface of the frame portion has a first region directly connected to the end face of the via electrode and a second region connected to the end face of the via electrode via the first region, the second region being perpendicular to the thickness direction, and the first region being inclined relative to the second region so that the thickness of the frame portion becomes smaller the closer it is to the end face of the via electrode. [Effects of the Invention]

[0022] According to the first aspect, the diameter DB of the bottom surface is smaller than the diameter DA of the end surface, so that the interface between the second surface of the frame portion and the third surface of the substrate portion is widened around the bottom surface of the via electrode. In other words, the lamination interface between the ceramics is widened around the bottom surface of the via electrode. Here, since the bottom surface of the via electrode is positioned so that LO > LI is satisfied, a large area where the lamination interface between the ceramics is located is ensured between the bottom surface and the outer edge of the second surface of the frame portion. Here, the lamination interface between the ceramics has higher airtightness than the lamination interface between the metal and the ceramic. Therefore, it is possible to suppress a decrease in airtightness due to leakage along the lamination interface.

[0023] According to the second aspect, the diameter DA of the via electrode is a minute dimension of 50 μm or less. This allows the width dimension of the frame portion to be made finer. As this miniaturization progresses, leakage along the lamination interface between the substrate portion and the frame portion becomes more likely to become a problem, but this problem is effectively suppressed for the reasons described above.

[0024] According to the third aspect, the minimum dimension between the inner edge and the outer edge of the second surface of the frame is 200 μm or less. As miniaturization advances, leakage along the lamination interface between the substrate and the frame becomes a more likely problem, but this problem is effectively suppressed for the reasons described above.

[0025] According to the fourth aspect, LO≧LI×1.5 is satisfied, which makes it possible to more sufficiently prevent a decrease in airtightness due to leakage along the lamination interface between the substrate portion and the frame portion.

[0026] According to the fifth aspect, the via electrode has a diameter of (DA+DB) / 2 or less at a midpoint between the end face and the bottom face in the thickness direction. This ensures a sufficient distance between the midpoint of the via electrode and the outer wall surface of the frame. This improves the airtightness reliability between the via electrode and the frame.

[0027] According to the sixth aspect, the via electrode has a portion that extends in a tapered shape from the end face in the thickness direction. This makes it easier to ensure a distance between the via electrode and the outer wall surface of the frame directly below the end face. This improves the reliability of airtightness between the via electrode and the frame.

[0028] According to the seventh aspect, the tapered shape of the via electrode extending from the end face has a taper angle of 5 degrees or more, which makes it easier to ensure a sufficient distance between the via electrode and the outer wall surface of the frame directly below the end face.

[0029] According to the eighth aspect, the tapered shape extending from the end face of the via electrode has a thickness equal to or greater than half the thickness of the frame, thereby enabling the tapered shape to more sufficiently increase the distance between the via electrode and the outer wall surface of the frame.

[0030] According to the ninth aspect, the side surface of the via electrode has at least one bending point, which makes it possible to prevent separation between the side surface of the via electrode and the frame portion due to sintering shrinkage during package manufacturing.

[0031] According to the tenth aspect, the side surface of the via electrode has two bending points that bend in opposite directions, which makes it possible to more sufficiently prevent separation between the side surface of the via electrode and the frame portion due to sintering shrinkage during package manufacturing.

[0032] According to the eleventh aspect, the outer wall surface of the frame has a fired surface connected to the first surface and a fractured surface connected to the second surface. The fractured surface is formed by a breaking process, and process variations can cause the distance between the outer edge of the second surface of the frame and the bottom surface of the via electrode to become small. However, as described above, since DA>DB and LO>LI are satisfied, this distance is unlikely to become too small. Therefore, it is possible to prevent insufficient airtightness of the frame due to this distance being too small.

[0033] According to the twelfth aspect, the metallization layer is locally thickened at the connection portion with the end face of the via electrode. This allows the obtuse angle formed between the side face of the via electrode and the first surface of the frame to be increased while maintaining the diameter DA of the end face and the diameter DB of the bottom face of the via electrode. This allows the thermal stress caused by the difference in thermal expansion between the via electrode and the metallization layer, which are mainly made of metal, and the frame, which is made of ceramic, to be alleviated.

[0034] According to the thirteenth aspect, the first region of the first surface of the frame is inclined so that the thickness of the frame decreases toward the end face of the via electrode. This makes it possible to increase the obtuse angle formed between the side surface of the via electrode and the first surface of the frame while maintaining the diameter DA of the end face and the diameter DB of the bottom face of the via electrode. This makes it possible to alleviate thermal stress caused by the difference in thermal expansion between the via electrode and the metallized layer, which are mainly made of metal, and the frame, which is made of ceramic.

[0035] The objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0036] [Figure 1] 1 is a plan view schematically illustrating a configuration of a quartz crystal resonator according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. [Figure 3] 2 is a plan view schematically showing one step of a method for manufacturing the quartz crystal resonator of FIG. 1. [Figure 4] FIG. 4 is a schematic cross-sectional view taken along line IV-IV in FIG. 3. [Figure 5] 1 is a plan view schematically showing a configuration of a package in accordance with a first embodiment of the present invention. [Figure 6] FIG. 6 is a schematic cross-sectional view taken along line VI-VI in FIG. 5. [Figure 7] FIG. 6 is a plan view in which the metallized layer and the frame portion in FIG. 5 are omitted. [Figure 8] 8 is a plan view schematically showing the substrate portion and via electrodes in FIG. 7, with package electrode pads indicated by dashed lines. FIG. [Figure 9] 6 is a plan view in which the metallized layer on the frame in FIG. 5 is omitted. [Figure 10] FIG. 10 is a schematic cross-sectional view taken along line XX in FIG. 9. [Figure 11] FIG. 10 is a partially enlarged view of FIG. [Figure 12] 1 is a partial cross-sectional view schematically showing a step in a method for manufacturing a package in accordance with a first embodiment of the present invention. [Figure 13] 1 is a partial cross-sectional view schematically showing a step in a method for manufacturing a package in accordance with a first embodiment of the present invention. [Figure 14] 1 is a partial cross-sectional view schematically showing a step in a method for manufacturing a package in accordance with a first embodiment of the present invention. [Figure 15] 11 is a diagram for explaining details of the configuration of the via electrodes shown in FIG. 10. FIG. [Figure 16] FIG. 16 is a diagram showing the configuration shown in FIG. 15 together with a metallized layer, taking into consideration the slight inclination of the upper surface of the frame portion. [Figure 17]FIG. 10 is a diagram for explaining details of the configuration of via electrodes included in the package according to the second embodiment of the present invention. [Figure 18] FIG. 18 is a diagram showing the configuration shown in FIG. 17 together with a metallized layer, taking into consideration the slight inclination of the upper surface of the frame portion. [Figure 19] FIG. 10 is a diagram for explaining details of the configuration of via electrodes included in a package according to a third embodiment of the present invention. [Figure 20] FIG. 20 is a diagram showing the configuration shown in FIG. 19 together with a metallized layer, taking into consideration the slight inclination of the upper surface of the frame portion. [Figure 21] 16 is a microscope photograph showing an embodiment corresponding to the configuration of FIG. 15. [Figure 22] 18 is a microscope photograph showing an embodiment corresponding to the configuration of FIG. 17. [Figure 23] 20 is a microscope photograph showing an embodiment corresponding to the configuration of FIG. 19. DETAILED DESCRIPTION OF THE INVENTION

[0037] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0038] <First Embodiment> Fig. 1 is a plan view schematically showing the configuration of a quartz crystal resonator 900 (electrical component) in the first embodiment. Fig. 2 is a schematic cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a plan view schematically showing the configuration immediately after mounting a quartz crystal blank 890 (electrical element) in a manufacturing method for the quartz crystal resonator 900 (Fig. 1). Fig. 4 is a schematic cross-sectional view taken along line IV-IV in Fig. 3.

[0039] The quartz crystal unit 900 includes a package 701, a quartz crystal blank 890, a brazing material 960, and a lid 980. The package 701 includes a cavity CV. The quartz crystal blank 890 is housed within the cavity CV and mounted on the device electrode pads 211 and 212 of the package 701. The lid 980 is bonded to the metallization layer 600 of the package 701 with the brazing material 960, thereby sealing the cavity CV. The brazing material 960 is preferably made of an alloy containing gold, such as an alloy containing gold and tin, or in other words, an Au-Sn alloy. The lid 980 is made of a metal, such as an alloy containing iron and nickel. Note that in this specification, an alloy is considered to be a type of metal.

[0040] The metallization layer 600 is made of a metal containing, for example, at least one of molybdenum and tungsten. A plating layer, typically a gold plating layer, may be provided on the surface of the metallization layer 600 (the surface facing the brazing material 960). A nickel plating layer may be provided as a base for the gold plating layer. In this embodiment, the metallization layer 600, which is provided directly on the frame top surface SF1 of the frame portion 120 of the package 701, and the lid 980 are joined together only by the brazing material 960.

[0041] Fig. 5 is a plan view schematically showing the configuration of a package 701. Fig. 6 is a schematic cross-sectional view taken along line VI-VI in Fig. 5. The package 701 has a ceramic part 100, an element electrode pad 211, an element electrode pad 212, and package electrode pads 301 to 304. In addition, the package 701 has a configuration for electrical wiring provided in the ceramic part 100, which will be described in detail later.

[0042] The ceramic portion 100 is made of ceramic, preferably containing an oxide as a main component, more preferably containing alumina as a main component, for example, substantially consisting of alumina. The ceramic portion 100 includes a substrate portion 110 and a frame portion 120. The material of the substrate portion 110 and the material of the frame portion 120 may be the same. The frame portion 120 is laminated on the substrate portion 110 in the thickness direction (the vertical direction in FIG. 6). The frame portion 120 has a frame upper surface SF1 (first surface) and a frame lower surface SF2 (second surface opposite the first surface in the thickness direction). The frame portion 120 also has an inner wall surface connecting the frame upper surface SF1 and the frame lower surface SF2 to each other, and this inner wall surface forms the side wall of the cavity CV. The substrate portion 110 has a substrate upper surface SF3 (third surface). The substrate upper surface SF3 has a support surface portion SF3S that supports the frame lower surface SF2 of the frame portion 120, and a cavity surface portion SF3C that faces the cavity CV. The cavity surface portion SF3C forms the bottom surface of the cavity CV.

[0043] The element electrode pads 211 and 212 (FIG. 5) are arranged on the ceramic part 100 (FIG. 6) facing the cavity CV. Specifically, the element electrode pads 211 and 212 are arranged on the upper surface (surface facing the cavity CV) of the substrate part 110 (FIG. 6). The package electrode pads 301-304 (FIG. 5) are arranged on the ceramic part 100 (FIG. 6) outside the cavity CV. Specifically, the package electrode pads 301-304 are arranged on the lower surface (surface opposite to the surface facing the cavity CV) of the substrate part 110 (FIG. 6).

[0044] The relay electrode 220 (FIG. 5) is provided on the substrate upper surface SF3 of the substrate portion 110 (FIG. 6). The relay electrode 220 is at least partially disposed on the support surface portion SF3S (FIG. 6). Thus, the relay electrode 220 (FIG. 5) is at least partially covered by the frame portion 120. The relay electrode 220 may further have a portion that is not covered by the frame portion 120 and is disposed on the bottom surface of the cavity CV. In other words, the relay electrode 220 may be only partially covered by the frame portion 120.

[0045] Fig. 7 is a plan view in which the metallized layer 600 (Fig. 5) and the frame portion 120 (Fig. 6) are omitted. Fig. 8 is a plan view that schematically shows the substrate portion 110 and substrate via electrodes 411-414 in Fig. 7, with package electrode pads 301-304 indicated by dashed lines.

[0046] Wiring layers 401 to 403 are embedded in the substrate part 110 of the ceramic part 100 near its upper surface. The wiring layer 401 is in contact with the element electrode pad 211, the wiring layer 402 is in contact with the element electrode pad 212, and the wiring layer 403 is in contact with the relay electrode 220. The wiring layers 401 to 403 may be covered with an insulating film 110i (see FIG. 10) as part of the substrate part 110 to the extent that this contact is not hindered, and in particular, the element electrode pad 211 and the wiring layer 403 are insulated by the insulating film 110i. The wiring layer 403 and the relay electrode 220 form the electrode layer 200.

[0047] The package 701 has substrate via electrodes 411 to 414 embedded in the substrate part 110 of the ceramic part 100. The substrate via electrode 411 connects the wiring layer 402 and the package electrode pad 301 to each other. The substrate via electrode 412 connects the wiring layer 403 and the package electrode pad 302 to each other. The substrate via electrode 413 connects the wiring layer 401 and the package electrode pad 303 to each other. The substrate via electrode 414 connects the wiring layer 403 and the package electrode pad 304 to each other.

[0048] With the above configuration, the element electrode pad 211 is electrically connected to the package electrode pad 303, the element electrode pad 212 is electrically connected to the package electrode pad 301, and the relay electrode 220 is electrically connected to the package electrode pad 302 and the package electrode pad 304.

[0049] Fig. 9 is a plan view in which the metallization layer 600 in Fig. 5 is omitted. Fig. 10 is a schematic cross-sectional view taken along line XX in Fig. 9. Fig. 11 is an enlarged view of a portion of Fig. 9.

[0050] The frame bottom surface SF2 of the frame 120 has an inner edge EI surrounding the cavity CV and an outer edge EO surrounding the inner edge EI. The minimum dimension WD (FIG. 11) between the inner edge EI and the outer edge EO may be 200 μm or less, and is typically 20 μm or more and 110 μm or less. The frame 120 has an outer wall surface SF4 connecting the frame top surface SF1 to the outer edge EO of the frame bottom surface SF2. The frame 120 also has an inner wall surface connecting the frame top surface SF1 to the inner edge EI of the frame bottom surface SF2, and the inner wall surface faces the cavity CV. In this embodiment, the outer wall surface SF4 has a firing surface SF4A connecting to the frame top surface SF1 and a fracture surface SF4B connecting to the frame bottom surface SF2. The fracture surface SF4B may be a surface approximately perpendicular to the frame top surface SF1. The firing surface SF4A may be a beveled surface that chamfers between the frame top surface SF1 and the fractured surface SF4B, as shown in Figure 10. In other words, the normal direction of the firing surface SF4A may be different from the normal directions of the frame top surface SF1 and the fractured surface SF4B, and may be between them.

[0051] As described above, the electrode layer 200 is formed on the substrate upper surface SF3 of the substrate unit 110 by the wiring layer 403 and the relay electrode 220. As described above, the substrate unit 110 has the insulating film 110i ( FIG. 10 ) as a part thereof. As a variant, the insulating film 110i may be omitted depending on the package design. The electrode layer 200 may also be formed by only either the wiring layer 403 or the relay electrode 220. For example, the electrode layer 200 may have the wiring layer 403 but omit the relay electrode 220. In this case, the boundary position between the wiring layer 403 and the insulating film 110i (the right end position of the wiring layer 403 in FIG. 10 ) may be shifted to the end position of the relay electrode 220 on the support surface portion SF3S (the right end position of the relay electrode 220 in FIG. 10 ), and the relay electrode 220 may be omitted. Furthermore, the edge of the insulating film 110i facing the cavity CV may be deformed to reach the frame portion 120, in which case the electrode layer 200 may be separated from the cavity CV by the insulating film 110i. Typically, the electrode layer 200 straddles the support surface portion SF3S and the cavity surface portion SF3C as shown in FIG. 10 , but as a variant, it may be disposed only on the support surface portion SF3S. In addition, the electrode layer 200 has an edge (the right edge in FIG. 10 ) away from the outer edge EO of the frame lower surface SF2 of the frame portion 120 in this embodiment, but this edge may be deformed to reach the outer edge EO.

[0052] The package 701 has a via electrode 510. The via electrode 510 penetrates the frame portion 120 between the frame upper surface SF1 and the frame lower surface SF2. The via electrode 510 has an end surface SFA on the frame upper surface SF1 and a bottom surface SFB on the frame lower surface SF2. In a plan view, the center position of the end surface SFA and the center position of the bottom surface SFB may be approximately the same. The bottom surface SFB is in contact with the electrode layer 200, and in this embodiment, is in contact with the relay electrode 220. As described above, the relay electrode 220 is in contact with the wiring layer 403, and the substrate via electrode 412 and the substrate via electrode 414 are connected to the wiring layer 403 (FIG. 7). Therefore, the substrate via electrode 412 and the substrate via electrode 414 are electrically connected to the via electrode 510. Furthermore, the end surface SFA of the via electrode 510 is in contact with the metallization layer 600 (FIG. 6). Therefore, the metallization layer 600 is electrically connected to the package electrode pad 302 and the package electrode pad 304 via the substrate via electrode 412 and the substrate via electrode 414, respectively (see FIG. 8).

[0053] The end surface SFA of the via electrode 510 has a diameter DA (FIG. 11). The diameter DA is smaller than the minimum dimension WD and may be 50 μm or less. The bottom surface SFB of the via electrode 510 has a diameter DB (FIG. 11) smaller than the diameter DA. The via electrode 510 preferably has a diameter of (DA+DB) / 2 or less at an intermediate position (average position between the positions of the end surface SFA and the bottom surface SFB) in the thickness direction (vertical direction in FIG. 10) between the end surface SFA and the bottom surface SFB. The taper ratio (the percentage of the diameter DB to the diameter DA) is preferably less than 60%.

[0054] In plan view (FIG. 11), the bottom surface SFB has a minimum dimension LI from the inner edge EI of the frame bottom surface SF2 of the frame portion 120, and a minimum dimension LO from the outer edge EO of the frame bottom surface SF2 of the frame portion 120. LO>LI is satisfied, and preferably LO≧LI×1.5 is satisfied.

[0055] 11, the shapes of the end surface SFA and the bottom surface SFB are approximately circular, but these shapes may be slightly different from a geometrically strict circular shape due to manufacturing errors. In this case, the diameters DA and DB may be calculated by approximating the end surface SFA and the bottom surface SFB with circular shapes.

[0056] 11, the inner edge EI of the frame bottom surface SF2 (see FIG. 10) has a first linear portion (a linear portion extending vertically in the drawing), a second linear portion (a linear portion extending horizontally in the drawing) extending perpendicular to the first linear portion, and a corner portion connecting these linear portions. The minimum dimension LI may be the dimension to this corner portion.

[0057] 12 to 14 are partial cross-sectional views schematically illustrating a process of a manufacturing method for simultaneously manufacturing multiple packages 701. For ease of explanation, the portion that will become the metallization layer 600 (FIG. 6) is omitted from FIGS. 12 to 14 . The metallization layer 600 can be formed by a well-known technique, for example, by applying a conductive paste and then firing it, and therefore its description is omitted. This firing may be performed in the same manner as the firing process described below. Also, FIGS. 12 and 13 show the state prior to the firing process that transforms the state of FIG. 13 into the state of FIG. 14 . Therefore, unlike the completed package 701, the components in FIGS. 12 and 13 are made of unfired materials. However, for ease of explanation, the same reference numerals as those representing the components of package 701 are used in FIGS. 12 and 13 , ignoring the difference in materials.

[0058] Green sheet 700G (FIG. 12) includes multiple regions 701G, each of which will eventually become package 701. In the state shown in FIG. 12, via electrodes 510 correspond to through holes filled with conductive paste. The through holes are formed by laser processing of green sheet 700G.

[0059] A trench TR1 (FIG. 13) is formed in the frame top surface SF1 of the green sheet 700G. A trench TR2 (FIG. 13) is also formed on the surface of the green sheet 700G opposite the frame top surface SF1. The trenches TR1 and TR2 are arranged to face each other in the thickness direction. The trenches TR1 and TR2 are formed, for example, by pressing a cutting edge against the green sheet 700G. Thereafter, a firing step is performed to fire the green sheet 700G (FIG. 13). After the firing step, a plating step may also be performed, if necessary.

[0060] The firing process forms a fired sheet 700F (FIG. 14). In the firing process, the inner surface of the trench TR1 is exposed to a firing atmosphere. Therefore, the inner surface of the trench TR1 of the fired sheet 700F becomes the firing surface. This firing surface becomes the firing surface SF4A (FIG. 10) of the package 701. A breaking process is performed in which a crack is generated from the trench TR1 by applying stress to the fired sheet 700F. The breaking process breaks the frame portion 120, thereby forming a fracture surface. This fracture surface becomes the fracture surface SF4B (FIG. 10) of the package 701. The breaking process may be a process in which a crack is generated between the trench TR1 and the trench TR2. In the breaking process, a plurality of packages 701 are cut out from the fired sheet 700F.

[0061] In the breaking process, a crack from the trench TR1 ideally propagates along the thickness direction as indicated by the solid arrow in the figure. However, in reality, as indicated by the dashed arrow in the figure, the crack may unintentionally approach one via electrode 510 (the via electrode 510 on the left side in the figure) more than the other via electrode 510 (the via electrode 510 on the right side in the figure). As a result, in a package 701 having the one via electrode 510, the minimum dimension LO ( FIG. 11 ) of the frame undersurface SF2 of the frame portion 120 may become smaller. Because an excessively small minimum dimension LO is likely to lead to leakage in the package 701, it is desirable that the minimum dimension LO have a certain amount of margin. According to the present embodiment, it is easy to ensure this margin.

[0062] 15 is a diagram for explaining the details of the configuration of the via electrode 510 (FIG. 10). The via electrode 510 has a portion that extends in a tapered shape from the end surface SFA to the bottom surface SFB throughout the thickness direction (vertical direction in the figure). This tapered shape has a taper angle TP of 5 degrees or more with respect to the thickness direction LD. AV Preferably, the via electrode 510 has a side surface connecting the end surface SFA and the bottom surface SFB. Points KA and KB indicate the positions of the side surface at the positions of the end surface SFA and the bottom surface SFB in the thickness direction, respectively. Point KV indicates the position of the side surface between points KA and KB in the thickness direction. Point KW indicates the position of the side surface between points KV and KB in the thickness direction. In this embodiment, points KV and KW are substantially located on the straight line connecting points KA and KB.

[0063] FIG. 16 is a diagram showing the configuration shown in FIG. 15 together with the metallized layer 600 (see FIG. 6 ), taking into consideration the slight inclination of the frame upper surface SF1, which was omitted in FIG. 15 . The frame upper surface SF1 of the frame portion 120 has an inclined region SF1d (first region) directly connected to the end surface SFA of the via electrode 510 and a parallel region SF1f (second region) connected to the end surface SFA of the via electrode 510 via the inclined region SF1d. The parallel region SF1f is perpendicular to the thickness direction. The inclined region SF1d is inclined relative to the parallel region SF1f so that the thickness of the frame portion 120 decreases toward the end surface SFA of the via electrode 510. The angle of inclination is, for example, 4° or more and 20° or less. The inclined region SF1d may surround the end surface SFA of the via electrode 510, and the parallel region SF1f may surround this inclined region SF1d. The metallized layer 600 is provided on the inclined region SF1d and the parallel region SF1f of the frame upper surface SF1, and is in contact with the end surface SFA of the via electrode 510.

[0064] According to this embodiment, as shown in FIG. 11, the diameter DB of the bottom surface SFB is smaller than the diameter DA of the end surface SFA. This widens the interface between the frame lower surface SF2 (FIG. 10) of the frame unit 120 and the substrate upper surface SF3 (FIG. 10) of the substrate unit 110 around the bottom surface SFB of the via electrode 510. In other words, the ceramic lamination interface is widened around the bottom surface SFB of the via electrode 510. Here, as shown in FIG. 11, the bottom surface SFB of the via electrode 510 is positioned so that LO > LI is satisfied, and therefore a large area where the ceramic lamination interface is located is secured between the bottom surface SFB and the outer edge EO of the frame lower surface SF2 of the frame unit 120. Here, the ceramic lamination interface has higher airtightness than the metal-ceramic lamination interface. This makes it possible to suppress a decrease in airtightness due to leakage along the lamination interface.

[0065] The diameter DA of the via electrode 510 may be 50 μm or less. This allows the minimum dimension WD (FIG. 11) of the frame portion 120 to be miniaturized. As this miniaturization progresses, leakage along the lamination interface between the substrate portion 110 and the frame portion 120 becomes more likely to become a problem, but this problem is effectively suppressed for the reasons described above.

[0066] The minimum dimension between the inner edge EI and outer edge EO of the frame undersurface SF2 of the frame portion 120 may be 200 μm or less. As miniaturization progresses, leakage along the lamination interface between the substrate portion 110 and the frame portion 120 becomes more likely to become a problem, but this problem is effectively suppressed for the reasons described above.

[0067] Referring to Figure 11, when LO≧LI×1.5 is satisfied, referring to Figure 10, the decrease in airtightness due to leakage along the laminated interface between the substrate upper surface SF3 of the substrate portion 110 and the frame lower surface SF2 of the frame portion 120 can be more sufficiently suppressed.

[0068] 11, the via electrode 510 may have a diameter of (DA+DB) / 2 or less at an intermediate position between the end surface SFA and the bottom surface SFB in the thickness direction (the vertical direction in FIG. 10). This ensures a sufficient distance between the intermediate position of the via electrode 510 and the outer wall surface SF4 of the frame 120. This improves the reliability of airtightness between the via electrode 510 and the frame 120.

[0069] The via electrode 510 has a portion that extends in a tapered shape from the end face SFA in the thickness direction (the vertical direction in FIG. 10). This makes it easier to ensure a distance between the via electrode 510 and the outer wall surface SF4 of the frame portion 120 directly below the end face SFA. This makes it possible to improve the reliability of airtightness between the via electrode 510 and the frame portion 120. Particularly in this embodiment, since the entire via electrode 510 extends in a tapered shape, this effect can be more fully obtained.

[0070] Taper Angle TP AV (FIG. 15) may be 5 degrees or more. This makes it easier to ensure a sufficient distance between the via electrode 510 and the outer wall surface SF4 (FIG. 10) of the frame portion 120 directly below the end surface SFA.

[0071] The outer wall surface SF4 (FIG. 10) of the frame 120 has a fired surface SF4A that connects to the frame upper surface SF1 and a fractured surface SF4B that connects to the frame lower surface SF2. The fractured surface SF4B is formed by the breaking process, and process variations can cause the minimum dimension LO (FIG. 11) to be small. However, as mentioned above, since DA>DB and LO>LI are satisfied, the minimum dimension LO is unlikely to be too small. This prevents the frame 120 from having insufficient airtightness due to the minimum dimension LO being too small.

[0072] By sloping the inclined region SF1d (FIG. 16) as described above, the obtuse angle SH formed between the side surface of the via electrode 510 and the frame upper surface SF1 can be increased while maintaining the diameters DA and DB of the via electrode 510 (FIG. 15). This can alleviate thermal stress caused by the difference in thermal expansion between the via electrode 510 and the metallized layer 600, which are mainly made of metal, and the frame 120, which is made of ceramic. This can prevent cracks or peeling between the via electrode 510 and the frame 120 caused by thermal stress.

[0073] Supplementally, assuming that the diameter DB (FIG. 15) is constant, the larger the diameter DA (FIG. 15), the larger the obtuse angle SH (FIG. 16). However, as mentioned above, there has been a recent demand for a smaller width of the frame portion 120, and accordingly, there is a design upper limit for the diameter DA. Furthermore, assuming that the diameter DA (FIG. 15) is constant, the smaller the diameter DB (FIG. 15), the larger the obtuse angle SH (FIG. 16). However, as the diameter DB becomes smaller, the area of ​​the bottom surface SFB of the via electrode 510 also becomes smaller. Therefore, in the configuration of FIG. 10, the electrical connection between the bottom surface SFB of the via electrode 510 and the relay electrode 220 of the electrode layer 200 is likely to be insufficient.

[0074] If the above-described effect of the inclined region SF1d is not particularly required, the inclined region SF1d may be omitted. In other words, in this case, the region of the frame upper surface SF1 that is directly connected to the end surface SFA of the via electrode 510 may be perpendicular to the thickness direction.

[0075] <Embodiment 2> 17 is a diagram for explaining the details of the configuration of the via electrode 520 of the package 702 in the second embodiment. The side surface of the via electrode 520 has at least one bending point in a cross section parallel to the thickness direction (FIG. 17), and specifically has points KV and KW as two bending points bending in opposite directions. The via electrode 520 has a portion 521 having a side surface from point KA to point KV, a portion 522 having a side surface from point KV to point KW, and a portion 523 having a side surface from point KW to point KB. The portion 521 extends in a tapered shape from the end face SFA in the thickness direction, and the taper angle TP of this tapered shape AV is preferably 5 degrees or more. Portion 521 preferably has a thickness equal to or greater than half the thickness of frame portion 120. Portion 522 has a more gradual tapered shape or a cylindrical shape compared to portion 521. Portion 523 has a more abrupt tapered shape compared to portion 522.

[0076] Fig. 18 is a diagram showing the configuration shown in Fig. 17 together with the metallized layer 600 (see Fig. 6), taking into consideration the slight inclination of the frame upper surface SF1 that was omitted in Fig. 17. The configuration shown in Fig. 18 corresponds to the configuration shown in Fig. 16 in which the via electrode 510 (first embodiment) is replaced with the via electrode 520 (second embodiment). The configuration shown in Fig. 18 also provides the same effects as those described in the first embodiment in relation to the configuration shown in Fig. 16.

[0077] Note that the configuration other than the above is substantially the same as the configuration of the first embodiment described above, and therefore the same or corresponding elements are given the same reference numerals and description thereof will not be repeated.

[0078] The portion 521 of the via electrode 520 has a thickness equal to or greater than half the thickness of the frame portion 120. This makes it possible to more sufficiently increase the distance between the via electrode 520 and the outer wall surface SF4 (see FIG. 10) of the frame portion 120 by the tapered shape.

[0079] The side surface of the via electrode 520 has bending points (specifically, points KV and KW), which can prevent separation between the side surface of the via electrode 520 and the frame portion 120 due to sintering shrinkage during the manufacture of the package 702. This effect is more sufficient because the bending points KV and KW are curved in opposite directions.

[0080] <Third Embodiment> 19 is a diagram for explaining the details of the configuration of the via electrode 530 of the package 703 in the third embodiment. The via electrode 530 has a portion 531 having a side surface from point KA to point KV, a portion 532 having a side surface from point KV to point KW, and a portion 533 having a side surface from point KW to point KB. The portion 531 extends in a tapered shape from the end face SFA in the thickness direction, and the taper angle TP of this tapered shape AV is preferably 5 degrees or more. Portion 531 preferably has a thickness equal to or greater than half the thickness of frame portion 120. Portion 532 has a reverse tapered shape in the direction from end face SFA to bottom face SFB. Portion 533 has a tapered shape in the direction from end face SFA to bottom face SFB.

[0081] Fig. 20 is a diagram showing the configuration shown in Fig. 19 together with the metallized layer 600 (see Fig. 6), taking into consideration the slight inclination of the frame upper surface SF1 that was omitted in Fig. 19. The configuration shown in Fig. 20 corresponds to the configuration shown in Fig. 16 in which the via electrode 510 (first embodiment) is replaced with the via electrode 530 (third embodiment). The configuration shown in Fig. 20 also provides the same effects as those described in the first embodiment in relation to the configuration shown in Fig. 16.

[0082] Since the configuration other than the above is substantially the same as that of the above-described second embodiment, the same or corresponding elements are denoted by the same reference numerals, and the description thereof will not be repeated. According to the present embodiment, the effect of suppressing peeling between the side surface of the via electrode 520 and the frame portion 120 due to sintering shrinkage is further enhanced compared to the second embodiment.

[0083] <Example> 12, in forming green sheet 700G (FIG. 12), the through holes to be filled with via electrodes 510 are formed by laser processing as described above. The packages of Examples 1 to 8 were fabricated by setting the laser light irradiation time and number of irradiations in this processing as shown in Table 1 below. In all Examples, laser light from a CO2 laser with a wavelength of 9.4 μm and an average output of 200 W was irradiated onto green sheet 700G through a mask with an opening diameter of 0.8 mm.

[0084] [Table 1]

[0085] In Examples 1 to 5, a shape corresponding to the via electrode 510 (FIG. 15) was obtained. Specifically, when point KV (FIG. 15) was set to the intermediate position (i.e., the average position) between points KA and KB in the thickness direction, and point KW (FIG. 15) was set to the intermediate position (i.e., the average position) between points KV and KB in the thickness direction, the diameter DA was 46 μm, the diameter DV (diameter passing through point KV) was 34 μm, the diameter DW (diameter passing through point KW) was 28 μm, and the diameter DB was 23 μm. The taper angle from point KA to point KB was 5.9 degrees, the taper angle from point KA to point KV was 6.1 degrees, the taper angle from point KV to point KW was 5.7 degrees, and the taper angle from point KW to point KB was 5.9 degrees. Thus, the entire via electrode had a substantially monotonous tapered shape within a range of 5.9±0.2 degrees. An example of a microscopic photograph taken during this observation is shown in FIG. 21.

[0086] In the example of FIG. 21, the metallization layer 600 (see FIG. 6) was locally thickened at the connection portion with the end face SFA (see FIG. 15) of the via electrode 510. The diameter DA (see FIG. 15) was measured at the connection portion (the portion indicated by the arrow in FIG. 21). This also applies to the examples of FIGS. 22 and 23 described below. The example of FIG. 21 corresponds to the configuration of FIG. 16, in which the metallization layer 600 protrudes downward from the dashed line portion (FIG. 16), thereby locally thickening at the connection portion with the end face SFA of the via electrode 510, and the obtuse angle SH (FIG. 16) was 113° on both the left and right sides of the via electrode 510.

[0087] In Example 6, a shape corresponding to the via electrode 520 ( FIG. 17 ) was obtained. Specifically, bending points such as points KV ( FIG. 17 ) and KW ( FIG. 17 ) were observed. In this observation, point KV ( FIG. 17 ) was approximately midway (i.e., the average position) between points KA and KB in the thickness direction, and point KW ( FIG. 17 ) was approximately midway (i.e., the average position) between points KV and KB in the thickness direction. The diameter DA was 47 μm, the diameter DV (diameter passing through point KV) was 34 μm, the diameter DW (diameter passing through point KW) was 33 μm, and the diameter DB was 23 μm. The taper angle from point KA to point KB was 6.1 degrees, the taper angle from point KA to point KV was 6.5 degrees, the taper angle from point KV to point KW was 0.8 degrees, and the taper angle from point KW to point KB was 10.5 degrees. An example of a microscopic photograph taken during this observation is shown in Figure 22. The example in Figure 22 corresponds to the configuration in Figure 18, in which the metallization layer 600 protrudes downward from the dashed line portion (Figure 18), thereby becoming locally thicker at the connection portion with the end face SFA of the via electrode 520, and the obtuse angle SH (Figure 18) was 114° on each of the left and right sides of the via electrode 520.

[0088] In Examples 7 and 8, a shape corresponding to the via electrode 530 (FIG. 19) was obtained. Specifically, bending points such as points KV (FIG. 19) and KW (FIG. 19) were observed. In this observation, point KV (FIG. 19) was approximately midway (i.e., the average position) between points KA and KB in the thickness direction, and point KW (FIG. 19) was approximately midway (i.e., the average position) between points KV and KB in the thickness direction. The diameter DA was 45 μm, the diameter DV (diameter passing through point KV) was 31 μm, the diameter DW (diameter passing through point KW) was 32 μm, and the diameter DB was 18 μm. The taper angle from point KA to point KB was 6.9 degrees, the taper angle from point KA to point KV was 6.9 degrees, the taper angle from point KV to point KW was −0.8 degrees, and the taper angle from point KW to point KB was 14.4 degrees. The taper angle from point KV to point KW has a negative value, which means an inverse taper shape. An example of a micrograph taken during this observation is shown in Figure 23. The example in Figure 23 corresponds to the configuration in Figure 20, in which the metallization layer 600 protrudes downward from the dashed line portion (Figure 20), thereby locally thickening at the connection portion with the end face SFA of the via electrode 530, and the obtuse angle SH (Figure 20) was 102° and 120° on the left and right sides of the via electrode 530 (Figure 20), respectively.

[0089] The first to third embodiments and their modifications of the present invention have been described above. These embodiments and modifications may be freely combined with one another as long as they do not contradict each other. [Explanation of symbols]

[0090] 100: Ceramic part 110i: insulating film 120: Frame 200: Electrode layer 220: Relay electrode 301~304: Package electrode pads 401~403: Wiring layer 411 to 414: Substrate via electrodes 510: Via electrode 520: Via electrode 530: Via electrode 600: Metallized layer 700F: Baking sheet 700G: Green sheet 701~703: Package CV: Cavity EI: Common-law marriage EO: Outer edge SF1: Top of frame (first surface) SF1d: Slope area (first area) SF1f: Parallel area (second area) SF4A: Baking surface SF4B: Fractured surface

Claims

1. A package having a cavity, a frame portion made of ceramic, the frame portion having a first surface and a second surface opposite to the first surface in a thickness direction, the second surface having an inner edge surrounding the cavity and an outer edge surrounding the inner edge, the package further comprising: a substrate portion made of ceramic, the substrate portion having a third surface having a portion supporting the second surface of the frame portion and a portion facing the cavity, the package further comprising: an electrode layer provided on the third surface of the substrate portion; a via electrode penetrating the frame portion between the first surface and the second surface, the via electrode having an end surface with a diameter DA at the first surface and a bottom surface with a diameter DB smaller than the diameter DA and in contact with the electrode layer at the second surface; a metallization layer provided on the first surface of the frame and in contact with the end surface of the via electrode, A package, wherein the metallization layer is locally thickened at a connection portion with the end face of the via electrode.

2. A package having a cavity, a frame portion made of ceramic, the frame portion having a first surface and a second surface opposite to the first surface in a thickness direction, the second surface having an inner edge surrounding the cavity and an outer edge surrounding the inner edge, the package further comprising: a substrate portion made of ceramic, the substrate portion having a third surface having a portion supporting the second surface of the frame portion and a portion facing the cavity, the package further comprising: an electrode layer provided on the third surface of the substrate portion; a via electrode penetrating the frame portion between the first surface and the second surface, the via electrode having an end surface with a diameter DA at the first surface and a bottom surface with a diameter DB smaller than the diameter DA and in contact with the electrode layer at the second surface; a metallization layer provided on the first surface of the frame and in contact with the end surface of the via electrode, a first surface of the frame portion having a first region directly connected to the end face of the via electrode and a second region connected to the end face of the via electrode via the first region, the second region being perpendicular to the thickness direction, and the first region being inclined relative to the second region such that the thickness of the frame portion becomes smaller the closer it is to the end face of the via electrode.

3. A package as described in claim 2, wherein the angle of inclination of the first region relative to the second region is greater than 4° and less than 20°.

4. The package of claim 1 , wherein the diameter DA is 50 μm or less.

5. The package according to claim 1 , wherein the minimum dimension between the inner edge and the outer edge of the second surface of the frame is 200 μm or less.

6. The package according to claim 1 , wherein the via electrode has a diameter of (DA+DB) / 2 or less at a middle position between the end surface and the bottom surface in the thickness direction.

7. The package according to claim 1 , wherein the via electrode has a portion that extends in a tapered shape from the end face in the thickness direction.

8. The package of claim 7 , wherein the tapered shape has a taper angle of 5 degrees or greater.

9. 9. The package according to claim 7, wherein the tapered shape has a thickness equal to or greater than half the thickness of the frame portion.

10. The package according to claim 1 , wherein the via electrode has a side surface connecting the end surface and the bottom surface, and the side surface has at least one bending point when viewed in a cross-sectional view parallel to the thickness direction.

11. 11. The package of claim 10, wherein the at least one flex point includes two flex points that bend in opposite directions.

12. the frame portion has an outer wall surface connecting the first surface and the outer edge of the second surface, The outer wall surface has a fired surface connected to the first surface and a fracture surface connected to the second surface. A package according to any one of claims 1 to 11.

Images