Ceramic package and manufacturing method of the same

Abstract

To easily form a highly reliable wiring pattern on an inner wall surface of a cavity of a ceramic package.SOLUTION: A ceramic package made by laminating ceramic green sheets has a cavity for accommodating an electronic component, and has a straight side part having a predetermined length and extending in a circumferential direction of an inner wall of the cavity at an inner peripheral edge part of an opening of the cavity in an upper part in a lamination direction, and forms an inclined part inclined toward a bottom surface of the cavity from the straight side part. On a surface of the inclined part, a wiring pattern extending from the outer peripheral edge part of the opening of the cavity to a vicinity of an end part on a bottom surface side of the inclined part is formed. On both side edge parts of the inclined part, a separation part for separating both side edge parts from other parts in the cavity are formed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a ceramic package having a cavity in which electronic components are arranged, a method for manufacturing the ceramic package, and an electronic device using the ceramic package.

Background Art

[0002] A ceramic package having a cavity for arranging electronic components by pressing and firing a laminate of ceramic green sheets can be provided with wiring patterns not only on the surface layer of the laminate but also between the layers, and thus is suitable for high-density circuits. In particular, in recent years, there is a need for a ceramic package that can accommodate electronic devices such as MEMS (Micro Electro Mechanical Systems) that have movable parts and are vulnerable to stress and cannot be directly sealed, and that has durability such as strength, weather resistance such as heat resistance, high heat dissipation, a small shape, and is low-cost and environmentally adaptable.

[0003] The cavity in the ceramic package is formed, for example, by the procedure described in Patent Document 1. That is, first, through holes for the cavity are formed in a plurality of green sheets arranged on the upper layer side among the ceramic green sheets corresponding to each layer of the ceramic multilayer substrate. At that time, the diameters of the through holes are made different for each layer, and the green sheets having the through holes for the cavity are sequentially laminated on a green sheet having no through holes for the cavity, starting from the green sheet with the smallest diameter.

[0004] That is, the through-holes for the cavities of the green sheets to be laminated are larger than the through-holes for the cavities of the green sheets located in the lower layer, and the required number of green sheets are laminated so that the diameter of the through-holes for the cavities of the green sheet laminated on the uppermost layer is the largest. As a result, a stepped wall surface is formed by the peripheral portions of the through-holes with different diameters, and this stepped wall surface becomes the inner wall surface of the cavity surrounding the mounting surface of the electronic component. Therefore, by pressing and firing the laminate formed by laminating the green sheets in this way, a ceramic multilayer substrate having a cavity in which the electronic component can be arranged can be obtained.

[0005] Comparing a ceramic substrate without a cavity and a ceramic package having a cavity, in the case of a ceramic substrate without a cavity, the routing of the wiring serving as the conduction path of the electronic component mounted on its surface layer is easier to manufacture and can improve productivity and conduction reliability in the wiring structure of aggregating the conduction paths on the surface layer rather than the wiring structure of making the via holes in series to conduct the wiring patterns between the surface layer and the interlayer.

[0006] On the other hand, in the case of a conventional ceramic package having a cavity, when trying to aggregate the conduction paths of the electronic components arranged in the cavity on the surface layer, since the wiring pattern has to be provided along the stepped inner wall surface formed on the inner wall of the cavity constituted by a plurality of green sheets, the manufacturing process becomes complicated and the reliability of conduction also decreases. That is, when the inner wall surface of the cavity is formed in a stepped shape by a plurality of green sheets, there arises a problem that it becomes difficult to provide a wiring pattern in the cavity.

[0007] When the electronic component mounted in the cavity of the ceramic package is a light-emitting element such as a chip LED, it is possible to increase the brightness by providing a reflective film made of a reflective material such as silver on the inner wall surface of the cavity. However, if the shape of the inner wall surface of the cavity is stepped, even if a reflective film is provided on the inner wall surface, light is diffusely reflected and there is a problem that the reflected light cannot be effectively utilized. Therefore, a method is known in which a metallization print is performed in advance on the green sheet that becomes the surface layer of the ceramic package, and it is pressed with a mold along the inner wall of the cavity so that a part of the metallized green sheet becomes the side surface of the cavity (for example, Patent Document 3). Note that Patent Document 2 discloses a method for forming a wiring pattern and a reflective film on the inner wall surface of the cavity.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] In the above-described ceramic package, for example, when the through-hole for the cavity has a round shape like the ceramic substrate described in Patent Document 2 or Patent Document 3, that is, when the through-hole for the cavity of the green sheet to be laminated is circular, the portion that becomes the side surface of the cavity in the surface green sheet extends in the direction of expansion when pressed, and extends particularly closer to the through-hole. Therefore, there is a problem that the green sheet may crack or the wiring pattern may crack. Further, even if there is no defect during manufacturing, there is a risk that cracks may occur in the ceramic surface or the wiring pattern on the cavity side surface due to aging deterioration, thereby reducing the reliability of the ceramic package.

[0010] Also, in the multilayer substrate described in Patent Document 2, since the wiring pattern on the inner wall surface and the wiring pattern on the inner bottom surface of the cavity are formed separately, when connecting the wiring pattern on the inner wall surface and the wiring pattern on the inner bottom surface of the cavity, there is a risk that the connection portion may be disconnected due to manufacturing defects or aging deterioration.

[0011] The present invention has been made in view of the above-described problems, and an object thereof is to provide a ceramic package capable of easily forming a highly reliable wiring pattern on the inner wall surface of a cavity.

Means for Solving the Problems

[0012] As one means for achieving the above object and solving the above-described problems, the ceramic package of the present invention has an opening above the stacking direction of a laminate obtained by stacking a plurality of ceramic green sheets, and has a cavity for accommodating predetermined components. The ceramic package includes one or more linear side portions having a predetermined length extending in the circumferential direction of the inner wall of the cavity at the inner peripheral edge portion of the opening, an inclined portion inclined toward the bottom surface of the cavity from the linear side portion, and a wiring pattern formed on the surface of the inclined portion and extending from the outer peripheral edge portion of the opening to the vicinity of the end portion on the bottom surface side of the inclined portion. The inclined portion is individually formed for each linear side portion, and a separation portion is formed in the cavity to separate both side edge portions of the inclined portion from other portions.

[0013] For example, the ceramic package further includes a bottom surface portion located at the lowermost layer of the laminate and covering the bottom surface of the cavity. A predetermined region on the bottom surface side of the inclined portion is in surface contact with the bottom surface portion, and a portion of the wiring pattern located in the predetermined region serves as a connection portion with the predetermined components accommodated in the cavity. Further, for example, the inclined portion is formed of one of the plurality of ceramic green sheets. Furthermore, for example, the inclined portion constitutes a single inclined portion in the cavity while having the separation portion, or constitutes a plurality of adjacent inclined portions in the inner circumferential direction in the cavity, or constitutes a plurality of opposing inclined portions in the cavity. Furthermore, the inclined portion includes a first inclined portion and a second inclined portion. The first inclined portion is formed of one of the plurality of ceramic green sheets, and the second inclined portion is formed of one of the other ceramic green sheets excluding the one layer among the plurality of ceramic green sheets. The first inclined portion is composed of two inclined portions opposing each other in a first direction orthogonal to the stacking direction in the cavity while having the separation portion, and the second inclined portion is composed of two inclined portions opposing each other in a second direction orthogonal to the first direction in the cavity while having the separation portion.

[0014] As one means for solving the above-described problems, a method for manufacturing a ceramic package according to the present invention includes a cavity for accommodating predetermined components, a first ceramic green sheet for forming the cavity, a second ceramic green sheet for forming an inclined portion on the inner wall of the cavity, and a third ceramic green sheet for forming the bottom surface of the cavity. The method further includes a step of forming through-holes having different inner diameters for each layer of the first ceramic green sheet in accordance with the inner diameter dimension of the cavity, a step of forming a wiring pattern on the surface of a portion of the second ceramic green sheet that becomes the inclined portion and forming holes or cuts in accordance with the shape and dimensions of the inclined portion, a lamination step of laminating the first ceramic green sheet having the through-holes formed thereon on the third ceramic green sheet, and laminating the second ceramic green sheet having the wiring pattern and the holes or cuts formed thereon on the laminated first ceramic green sheet to form an un-pressed laminate, a pressing step of applying isotropic pressure to the un-pressed laminate to form an unfired block body having a multilayer structure, and a firing step of firing the unfired block body. In the lamination step, the first ceramic green sheet forms one or more linear side portions having a predetermined length on the inner peripheral edge portion on the opening side of the cavity and a stepped portion extending from the linear side portion to the bottom surface of the cavity on the inner wall of the cavity. In the pressing step, the second ceramic green sheet forms the inclined portion having the stepped portion as a base, so that the wiring pattern is arranged to extend from the outer peripheral edge portion on the opening side to the vicinity of the end portion on the bottom surface side of the cavity in the inclined portion, and a separation portion is formed in the cavity to separate both side edge portions of the inclined portion from other portions.

[0015] For example, the wiring pattern and the holes or cuts are formed on a ceramic green sheet selected from the first ceramic green sheet, and the inclined portion is formed on the inner wall of the cavity by the selected ceramic green sheet.

[0016] As another means for solving the above-described problems, the electronic device of the present invention accommodates a predetermined component in a cavity having an opening above the stacking direction of a ceramic package manufactured by pressing and firing a laminate of a plurality of ceramic green sheets, and has one or more linear side portions of a predetermined length formed on an inner peripheral edge portion of the opening of the cavity, and an inclined portion inclined toward a bottom surface of the cavity from the linear side portion, and includes a wiring pattern formed on a surface of the inclined portion and extending from an outer peripheral edge portion of the opening to a vicinity of an end portion on the bottom surface side of the inclined portion. The ceramic package has a circuit connection portion between an inner peripheral edge portion and an outer peripheral edge portion of the opening of the cavity to enable electrical connection with other devices. One end of the wiring pattern is connected to the predetermined component, and the other end is connected to the circuit connection portion. A separation portion is formed in the cavity to separate both side edge portions of the inclined portion from other portions.

[0017] For example, the predetermined component is an electronic component including at least a light-emitting diode (LED) and a sensor element.

Advantages of the Invention

[0018] According to the present invention, a wiring pattern can be easily provided on an inner wall surface of a cavity in which an electronic component is disposed, and a ceramic package capable of maintaining high reliability as an electronic device in which an electronic component is accommodated in the cavity can be provided.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

MODE FOR CARRYING OUT THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. <Embodiment 1> FIG. 1 is an external perspective view showing the overall configuration of the ceramic package according to Embodiment 1 of the present invention. As shown in FIG. 1, the ceramic package 1 according to Embodiment 1 has an overall cubic shape, and when viewed from the upper surface side, a space (cavity) 2 in the shape of a rectangle (square) in plan view and having a predetermined depth is provided in the central portion thereof. At least one inner surface of the inner surface of the cavity 2 has an inclined portion, and a wiring pattern is formed on the upper surface of the inclined portion. In the example shown in FIG. 1, among the four inner surfaces, inclined portions 3a and 3b are formed on two opposite side surfaces, and wiring patterns 5a and 5b are formed on the upper surfaces of the inclined portions 3a and 3b, respectively.

[0021] The ceramic package 1 is composed of a laminate in which a plurality of ceramic green sheets are laminated. The inclined portions 3a and 3b are formed of the top-layer green sheet as will be described later, but may be formed of the second or third layer green sheet of the upper layer.

[0022] On the inner peripheral portion of the cavity 2, a stepped inner wall described later is formed, and on the upper edge portion of the inner peripheral wall, linear side portions 1a and 1b extending in the circumferential direction of the inner wall with a predetermined length are provided. The inclined portions 3a and 3b have one end of these side portions 1a and 1b, and the other end extends to the bottom surface 4 of the cavity 2 and is in planar contact with a part of the bottom surface 4. The wiring patterns 5a and 5b extend from the outer peripheral edge portion of the cavity 2 to the portion where the inclined portions 3a and 3b are in planar contact with a part of the bottom surface 4.

[0023] In the ceramic package, the inclined portions are individually formed for each side at the upper edge portion of the inner peripheral wall of the cavity. In the example shown in FIG. 1, the inclined portions 3a and 3b are formed corresponding to the opposing sides among the upper edge portions of the inner peripheral wall. Further, the inclined portion 3a has separation portions 7a and 7b that do not contact and are separated from the inner wall of the cavity and the like at both side edge portions thereof, and similarly, the inclined portion 3b also has separation portions 7c and 7d at both side edge sides thereof.

[0024] Among the wiring patterns 5a and 5b, the wiring pattern located at the portion where the other end of the above-described inclined portions 3a and 3b is in planar contact with a part of the bottom surface 4 serves as a connection portion for an electronic component housed and arranged in the cavity 2.

[0025] Next, a method for manufacturing the ceramic package according to Embodiment 1 will be described. FIG. 2 is a flowchart showing the manufacturing process of the ceramic package according to Embodiment 1 in chronological order.

[0026] The ceramic package according to Embodiment 1 is manufactured by pressing a laminate obtained by laminating a plurality of ceramic green sheets with an isostatic pressing device. First, in step S1 of FIG. 2, a bottom surface ceramic green sheet for forming the bottom surface 4 of the cavity 2, a cavity ceramic green sheet laminated on the upper part of the bottom surface ceramic green sheet for forming the cavity 2, and an inclined portion ceramic green sheet for forming the inclined portions 3a and 3b on the inner wall of the cavity 2 while forming the cavity 2 are prepared.

[0027] Here, since the thickness of the ceramic green sheet is about 0.1 mm, a bottom surface ceramic green sheet with the number of sheets such that the thickness after lamination becomes the thickness of the bottom surface 4 of the cavity 2, and a cavity ceramic green sheet and an inclined portion ceramic green sheet with the number of sheets such that the height in the vertical direction of the cavity 2 are prepared.

[0028] In step S3, the ceramic green sheets prepared in step S1 are laminated in the order of the bottom surface ceramic green sheet 21, the cavity ceramic green sheet 23, and the inclined portion ceramic green sheet 25 as shown in FIG. 3A to form an unbonded laminate.

[0029] In each of the plurality of cavity ceramic green sheets 23 laminated on the upper portion of the bottom surface ceramic green sheet 21, cavity holes with different diameters are formed in advance. Here, after lamination, the diameters of the holes provided in the cavity ceramic green sheets 23 to be laminated are set such that two of the four inner walls of the cavity 2 that face each other become stepped, and the other two inner walls that face each other become vertical.

[0030] Specifically, the diameter of the cavity hole of the green sheet (the lowermost green sheet) of the cavity ceramic green sheet 23 in contact with the bottom surface ceramic green sheet 21 among the cavity ceramic green sheets 23 to be laminated is the smallest, and the diameter of the cavity hole gradually increases from the lower layer to the upper layer of the lamination. Therefore, the diameter of the cavity hole formed in the uppermost green sheet of the cavity ceramic green sheet 23 is the largest. Although through-holes for the cavity are not formed in the bottom surface ceramic green sheet 21, through-holes 8 used for heat dissipation or the like may be formed when electronic components are mounted in the cavity as described later.

[0031] In the ceramic green sheet 23 for the cavity, by setting the aperture diameter of the hole for the cavity as described above, a cavity 2 having a concave shape with a rectangular shape in plan view is formed in the central portion of the laminate formed by laminating the ceramic green sheets 23 for the cavity as shown in FIG. 3A. Two opposing inner walls 13a and 13b of the cavity 2 are stepped, and the other two opposing inner walls 19a and 19b are vertical walls.

[0032] In the ceramic green sheet 25 for the inclined portion, as shown in FIG. 3A, a through hole 27 having an H shape in plan view is formed in advance by sheet punching, and further, wiring patterns 5a and 5b are formed by screen printing. For the wiring patterns 5a and 5b, for example, an Ag-based thick film electrode material is used. Note that the through hole 27 may be formed by a laser. Further, instead of the through hole, an H-shaped cut (slit) may be made by a laser. Further, a combination of the through hole and the cut may be used. The order of the sheet punching process and the screen printing may be either one first.

[0033] FIG. 3B is an external view of the unbonded laminate formed by laminating the ceramic green sheets as described above. Further, FIG. 4(a) is a cross-sectional view when the unbonded laminate 11 shown in FIG. 3 is cut along the X-X' line of sight.

[0034] The ceramic green sheet 25 for the inclined portion located at the uppermost layer of the unbonded laminate 11 is in a state of protruding above the cavity 2 formed by the laminated ceramic green sheets 23 for the cavity as shown in FIG. 4(a). Therefore, in step S5, the unbonded laminate formed in step S3 is put into a bag and vacuum-packed, and further pressed by an isostatic pressing device to form an unfired block body 30 having a multilayer structure shown in FIG. 6.

[0035] Due to the pressure applied to form the unfired block body 30 in step S5, the protruding portions 25a and 25b of the ceramic green sheet 25 for the inclined portion, which protrude above the cavity 2, bend along the portion in contact with the upper edge of the ceramic package 1 as indicated by the arrows in Fig. 4(a), and sink into the cavity 2 together with the wiring patterns 5a and 5b.

[0036] As a result, the protruding portions 25a and 25b of the ceramic green sheet 25 for the inclined portion, which protrude above the cavity 2, cover the stepped portions (stepped inner walls) 13a and 13b formed by the ceramic green sheet 23 for the cavity as shown in Fig. 4(b), and inclined portions 3a and 3b are formed as gentle inclined walls with smooth surfaces in the cavity 2.

[0037] Among the inclined portions 3a and 3b formed in this way, the portions that bend while being continuous with the horizontal portion at the upper edge of the cavity 2 (the portions surrounded by the broken lines 24a and 24b in Fig. 4(b), also referred to as the first bending portions), and the portions that bend while being continuous with the portion in planar contact with the bottom surface 4 of the cavity 2 (the portions surrounded by the broken lines 26a and 26b in Fig. 4(b), also referred to as the second bending portions) have a shape with gentle rounding (round (R)). Therefore, the risk of disconnection of the wiring patterns 5a and 5b at these bending portions is reduced.

[0038] Regarding the inclined portion in the cavity, for example, as shown in Fig. 5(a), by changing the shape of the stepped portion 29 of the inner wall of the cavity formed by the laminated green sheets, and bending the protruding portions 25a and 25b above the cavity 2 along the portion in contact with the upper edge of the ceramic package 1 as indicated by the arrows, the cross-section of the inclined portions 3a and 3b has a rounded shape as shown in Fig. 5(b).

[0039] In step S7, the unfired block body 30 formed in step S5 is cut into an outer shape that matches the size of the ceramic package as indicated by the dashed line in FIG. 6, for example, by die pressing or dicing, and then fired. Then, conductor surface treatment is performed on the fired block body by electroless plating. In electroless plating, for example, Ni underplating and Au surface plating are applied.

[0040] In the above-described ceramic green sheet lamination step, on the upper edge portion (also referred to as the inner peripheral edge portion on the opening side of the cavity) of the portion where the cavity ceramic green sheet 23 is laminated to form a stepped inner wall in the cavity 2, in accordance with the number of inclined portions in the cavity 2, linear side portions extending in the circumferential direction of the inner wall of the cavity are formed. By doing so, in the pressure bonding step of the ceramic green sheet, inclined portions 3a, 3b are formed that are inclined at a predetermined angle from the linear side portions toward the bottom surface of the cavity 2 and on which wiring patterns 5a, 5b arranged from the outside to the inside of the cavity are disposed on the surface.

[0041] Here, the relationship among the inclination angle of the inclined portion, the planar view H-shaped through hole formed in the inclined portion ceramic green sheet 25, and the wiring pattern in the ceramic package according to Embodiment 1 will be described.

[0042] As shown in FIG. 7, when the length of the wiring patterns 5a, 5b screen-printed on the inclined portion ceramic green sheet 25 is A, the depth of the cut of the planar view H-shaped through hole 27 formed by sheet punching is B, and as shown in FIG. 8, the depth of the cavity 2 in the ceramic package is D, then A is the longest and D is the shortest, and the relationship A > B > D holds.

[0043] Also, let the angle formed by the bottom surface 4 of the ceramic package and the inclined portions 3a, 3b of the cavity 2 be θ, the length of the inclined portions 3a, 3b be b1, the length of the inclined portions 3a, 3b on the bottom surface 4 (the length of the portion where the inclined portion contacts the bottom surface) be b2, and the length of the circuit connection portion, which is the portion of the wiring patterns 5a, 5b located at the upper edge of the wall portion of the cavity 2, be a1. Then, the relationship between the length b1 of the inclined portion and the depth of the cavity is D ≒ b1 × sinθ.

[0044] When designing the depth B of the cut of the through hole 27, considering D, b2, and θ, it is set as B ≒ b1 + b2 = (D / sinθ) + b2. Also, when designing the length A of the wiring patterns 5a, 5b, considering B and a1, it is set as A ≒ B + a1.

[0045] In the first embodiment, the inclination angle θ of the inclined portions 3a, 3b is set to 60° or less, more preferably 45° or less. When the inclination angle θ is 60° or more, cracks may occur in the cavity at the first bending portion and the second bending portion described above.

[0046] In the ceramic package according to the first embodiment, as shown in FIG. 7, by forming the through holes 27 in the ceramic green sheet 25 for the inclined portion, when the unfired block body with the ceramic green sheet 25 for the inclined portion as the uppermost layer is pressed by an isostatic pressing device, the convex portion 77a with both ends sandwiched by the through holes 27a, 27b sinks into the cavity, and the inclined portion 3a is formed.

[0047] And due to the presence of the through holes 27a, 27b, when pressed by the isostatic pressing device, uniform pressure is applied to the uppermost ceramic green sheet 25 for the inclined portion, preventing cracks and the like from occurring in the green sheet. Further, in the inclined portion 3a formed by the sinking of the convex portion 77a, separation portions 7a, 7b are formed where both side edges 74a, 74b of the convex portion 77a are separated from other portions in the cavity (such as the side walls without inclined portions) and do not interfere with each other.

[0048] Similarly, regarding the convex portion 77b, due to the presence of the through holes 27c and 27d, in the inclined portion 3b formed by the depression of the convex portion 77b, separation portions 7c and 7d are formed where both side edges 74c and 74d of the convex portion 77b are separated from other portions within the cavity, such as side walls without inclined portions.

[0049] In the ceramic package according to Embodiment 1, the cavity serves as a space region for mounting electronic components. FIG. 9(a) is an external perspective view of an electronic device 73 in which an electronic component 75 is mounted in the cavity 2 of the ceramic package, and FIG. 9(b) is an external perspective view showing a state in which the electronic device 73 of FIG. 9(a) is mounted on a circuit board (not shown) with the through hole 8 provided on the bottom surface of the ceramic package facing upward.

[0050] As described above, the ceramic package according to Embodiment 1 includes a linear side portion of a predetermined length extending in the circumferential direction of the inner wall of the cavity at the inner peripheral edge of the cavity, and an inclined portion inclined toward the bottom surface of the cavity is formed from the linear side portion. In the green sheet of the surface layer that becomes the inclined portion, a hole for making the opening shape of the cavity rectangular and a cut are formed with the through hole partitioning the inclined portion. Therefore, when pressed, the green sheet of the surface layer bends starting from the linear side portion and does not extend more in the portion closer to the through hole. As a result, neither cracks occur in the green sheet nor cracks occur in the wiring pattern formed on its surface.

[0051] In addition, since the package shape that embodies the mechanical function of the ceramic package and the conductor pattern that provides the electrical function can be formed simultaneously, the assembly man-hours can be reduced, and the ceramic package can be manufactured at low cost. Further, since there are no multi-layer patterns and via connections in the ceramic package, the number of components is small and the package can be miniaturized.

[0052] Furthermore, a wiring pattern leading from the outside to the inside of the cavity is formed by screen printing on the same plane. In the wiring pattern, gentle rounded corners are formed at the continuous part (the first bent part) in the horizontal part of the upper edge of the ceramic package and the continuous part (the second bent part) in the part in contact with the bottom surface of the cavity, thereby reducing the risk of disconnection of the wiring pattern and maintaining high reliability as an electronic device in which electronic components are housed in the cavity.

[0053] Also, holes are formed in the ceramic green sheet for the bottom surface and used as through holes in the bottom surface part of the cavity, so that the through holes become exposed hole parts for detecting external information (humidity, temperature, pressure, sound, vibration, etc.). Further, by using the through holes as heat dissipation vias, heat dissipation paths for mounted light-emitting diodes (LEDs) and MEMS sensors can be provided. Furthermore, a lens-shaped lid (device package / cover) can be formed on the bottom surface part of the cavity to form an optical device.

[0054] When connecting the ceramic package according to the first embodiment to a circuit board (resin, LTCC (Low Temperature Co-fired Ceramics)), the parts outside the cavity of the wiring patterns 5a and 5b formed on the ceramic green sheet 25 for the inclined part (the horizontal part of the upper edge of the ceramic package) can be mounted using solder balls or the like. When airtightness is required for the ceramic package, the gap between the ceramic package and the circuit board is sealed with an epoxy resin, a silicone resin, a low-temperature fired glass, etc., thereby maintaining the airtightness inside the package. In particular, when the ceramic package is mounted on an LTCC circuit board, by making the ceramic package of the same material as the LTCC substrate circuit, there is no difference in thermal expansion between the ceramic package and the circuit board, enabling highly reliable mounting.

[0055] Although illustration is omitted, in the electronic device 73 shown in Fig. 9(a), by filling the inside of the cavity 2 on which the electronic component 75 is mounted with a molding resin, the internal components can be protected. Further, when the opening side of the cavity is mounted as the upper surface, wire bonding may be performed on the portions of the wiring patterns 5a and 5b that are exposed outside the cavity to serve as input / output signal paths to the outside.

[0056] <Embodiment 2> Regarding the cavity of the ceramic package according to the present invention, it is not limited to the form in which inclined portions are provided on two opposing sides (two inner wall surfaces) as in Embodiment 1. The ceramic package according to Embodiment 2 has, for example, a configuration in which stepped inner walls 31a to 31d are formed on four sides (four inner wall surfaces) of the cavity 32, and inclined portions are provided on the four sides of the cavity 32 so as to cover the inner walls 31a to 31d, like the ceramic green sheet 36 for the cavity shown in Fig. 10.

[0057] Fig. 11(a) is a plan view of the uppermost-layer ceramic green sheet 35 for the inclined portion that is laminated to form the ceramic package according to Embodiment 2. A rectangular through-hole 37 is formed in the central portion of the ceramic green sheet 35 for the inclined portion by sheet punching, and cuts (slits) 38a to 38d are formed from each of the four corners (vertices) of the through-hole 37 toward the four corners (vertices) of the ceramic green sheet 35 for the inclined portion by laser.

[0058] As shown in Fig. 11(b), wiring patterns 34a to 34d are formed in the four regions 78a to 78d defined by the slits 38a to 38d on the ceramic green sheet 35 for the inclined portion. Note that the wiring patterns 34a to 34d are not limited to the shape that is bent in a plan view as shown in Fig. 11(b), and may be in a shape that extends linearly between the through-hole 37 and the end of the ceramic green sheet 35 for the inclined portion.

[0059] FIG. 11(c) is a plan view of an unfired block body 40 obtained by pressing an unbonded laminate having the ceramic green sheet 35 for inclined portions shown in FIG. 11(b) as the uppermost layer with an isostatic press device. As shown in FIG. 11(c), in the ceramic package according to Embodiment 2, inclined portions 33a to 33d as inclined walls with a smooth surface are formed in the cavity 32.

[0060] In Embodiment 2, the slits 38a to 38d formed in the ceramic green sheet 35 for inclined portions absorb the elongation of the ceramic green sheet 35 for inclined portions when the ceramic green sheet 35 for inclined portions sinks into the cavity 32 during pressing, and can prevent cracks and the like from occurring in the ceramic green sheet 35 for inclined portions. Further, due to the presence of the slits 38a to 38d, separation portions 39a to 39d that physically separate each inclined portion from other adjacent inclined portions are formed at both side edges of the inclined portions 33a to 33d formed by pressing.

[0061] The outer shape of the ceramic package according to the present invention is not limited to a cube as in Embodiment 1, and may be a hexagonal prism shape shown in FIG. 12 or a cylindrical shape shown in FIG. 13.

[0062] <Embodiment 3> FIG. 12(a) is a plan view of the ceramic green sheet 45 for inclined portions of the uppermost layer laminated to form a ceramic package having a hexagonal prism outer shape according to Embodiment 3. A hexagonal through-hole 47 is formed in the center of the ceramic green sheet 45 for inclined portions by sheet punching. Further, cuts (slits) 48a to 48f extending from each of the six corners (vertices) of the through-hole 47 toward each of the six corners (vertices) of the ceramic green sheet 45 for inclined portions are formed by a laser.

[0063] As shown in FIG. 12(b), wiring patterns 44a to 44f extending linearly between the through-hole 47 and the end of the green sheet 45 are formed in each of the six regions 88a to 88f defined by the slits 48a to 48f in the ceramic green sheet 45 for inclined portions.

[0064] When the unbonded laminate with the ceramic green sheet 45 for the inclined portion shown in Fig. 12(b) as the top layer is pressed with an isostatic press device, an unfired block body 50 having the configuration shown in Fig. 12(c) is obtained when viewed in plan. That is, in the ceramic package according to Embodiment 3, inclined portions 43a to 43f as inclined walls with a smooth surface are formed in the cavity 42.

[0065] Also in Embodiment 3, the slits 48a to 48f formed in the ceramic green sheet 45 for the inclined portion absorb the elongation of the ceramic green sheet 45 for the inclined portion when the ceramic green sheet 45 for the inclined portion sinks into the cavity 42 during pressing. Therefore, it is possible to prevent cracks and the like from occurring in the ceramic green sheet 45 for the inclined portion of the top layer due to pressing. Further, after pressing, separation portions 49a to 49f that physically separate each inclined portion from other adjacent inclined portions are formed on both side edges of the inclined portions 43a to 43f by the slits 48a to 48f.

[0066] <Embodiment 4> Fig. 13(a) is a plan view of the ceramic green sheet 68 for the inclined portion of the top layer laminated to form a ceramic package having a cylindrical outer shape according to Embodiment 4. The ceramic green sheet 68 for the inclined portion has a through hole 57 formed by die punching while leaving a region 98 that will become the inclined portion 53 described later. A wiring pattern 54 is formed in the region 98 by screen printing.

[0067] Fig. 13(b) is an external view in plan of the unfired block body 60 obtained by pressing the unbonded laminate with the ceramic green sheet 68 for the inclined portion shown in Fig. 13(a) as the top layer with an isostatic press device. As shown by the broken line in Fig. 13(b), a straight side portion 58 is provided at at least one location on the inner peripheral side of the upper edge portion of the cavity 52. Then, in the cavity 52, an inclined portion 53 that inclines at a predetermined angle toward the bottom surface of the cavity 52 starting from the straight side portion 58 is formed so as to cover the stepped wall surface 55. A wiring pattern 54 is formed on the surface of the inclined portion 53.

[0068] <Embodiment 5> FIG. 14 is an exploded perspective view of the ceramic package according to Embodiment 5. The ceramic package 61 according to Embodiment 5 has a structure in which a plurality of ceramic green sheets 62 for cavities are laminated to form stepped inner walls on each of the four inner wall surfaces of the cavity 82, and inclined portion ceramic green sheets 63 and 64 for forming inclined portions covering these four stepped inner walls are sequentially laminated on the uppermost part in the lamination direction of the cavity 82.

[0069] In the inclined portion ceramic green sheet 63, a through hole 67 having an H shape in plan view is formed in advance by sheet punching, and further, wiring patterns 65a and 65b are formed by screen printing. The inclined portion ceramic green sheet 64 is composed of a pair of green sheets 64a and 64b whose overall shapes are processed into an E shape in plan view by sheet punching, and wiring patterns 66a and 66b are formed at predetermined positions by screen printing.

[0070] FIG. 15 is an external perspective view of an unbonded laminate 71 formed by laminating the cavity 62 shown in FIG. 14 and the inclined portion ceramic green sheets 63 and 64. In the unbonded laminate 71, portions 83a, 83b, 84a, and 84b where the wiring patterns are formed in the inclined portion ceramic green sheets 63 and 64 protrude above the cavity 82 and are in a floating state in the air. When this unbonded laminate is pressed by an isostatic pressing device, the protruding portions 83a, 83b, 84a, and 84b are bent and sink into the cavity 82 together with the wiring patterns.

[0071] As a result, as shown in FIG. 16, the protruding portions 83a, 83b, 84a, and 84b of the inclined portion ceramic green sheets 63 and 64 are deformed and covered along the four stepped shapes formed on the inner wall of the cavity, whereby a multilayer ceramic package 91 having inclined portions 69a to 69d is obtained.

[0072] FIG. 17 shows an electronic device 93 in which an electronic component 97 is mounted on the ceramic package shown in FIG. 16. Here, a sensor, an LED, a semiconductor element, etc. are placed as the electronic component 97 at the center of the bottom of the cavity of the ceramic package, and the signal terminals of the electronic component 97 and the wiring patterns 95a to 95d formed on the surfaces of the inclined portions 69a to 69d, which serve as the input / output signal paths of the ceramic package, are electrically connected by wire bonding or the like.

[0073] In the above-described Embodiment 2 in which four inclined portions are formed in the cavity, instead of the uppermost-layer inclined-portion ceramic green sheet 35, three inclined portions are formed on the inner wall of the cavity by one layer of ceramic green sheet selected from a plurality of ceramic green sheets constituting the cavity, and one inclined portion is formed on the inner wall of the cavity by another one layer of ceramic green sheet selected from a plurality of ceramic green sheets constituting the cavity.

[0074] Similarly, in the above-described Embodiment 3, instead of the uppermost-layer inclined-portion ceramic green sheet 45, six inclined portions may be formed on the inner wall of the cavity by several layers of ceramic green sheets selected from a plurality of ceramic green sheets constituting the cavity.

[0075] Also, in each of the above-described embodiments, among the wiring patterns formed on the surface of the inclined portion, the pattern width at the bent portion of the inclined portion may be formed wider than that of other portions. By doing so, it is possible to prevent the wiring pattern at the bent portion from being disconnected when the laminate is pressurized.

Explanation of Reference Numerals

[0076] 1,91 Ceramic package 1a,1b,58 Straight-side portions 2,32,42,52,62,82 Cavity 3a,3b,33a~33d,43a~43f,53,69a~69d Inclined portions 4 Bottom surface Wiring patterns of 5a, 5b, 34a to 34d, 44a to 44f, 54, 65a, 65b, 66a, 66b, 95a to 95d Spaced portions of 7a to 7d, 39a to 39d Uncrimped laminate of 11, 71 Step-shaped inner walls of 13a, 13b, 31a to 31d Vertical inner walls of 19a, 19b Ceramic green sheet for bottom surface of 21 Ceramic green sheet for cavity of 23, 36 Ceramic green sheet for inclined portion of 25, 35, 45, 63, 64, 68 Overhanging portions of green sheet of 25a, 25b, 83a to 84b Through holes of 27, 27a to 27d, 37, 47, 57, 67 Unfired block bodies of 30, 40, 50, 60 Cuts (slits) of 38a to 38d, 48a to 48f Electronic devices of 73, 93 Both side edge portions of 74a to 74d Electronic components of 75, 97 Convex portions of 77a, 77b

Claims

1. A ceramic package having an opening above the lamination direction of a laminate formed by laminating a plurality of ceramic green sheets and having a cavity for accommodating a predetermined component, one or more linear side portions of a predetermined length extending in the circumferential direction of the inner wall of the cavity at the inner peripheral edge of the opening, an inclined portion inclined toward the bottom surface of the cavity from the linear side portion, and a wiring pattern formed on the surface of the inclined portion and extending from the outer peripheral edge of the opening to the vicinity of the end on the bottom surface side of the inclined portion, characterized in that the inclined portion is formed individually for each of the linear side portions, and a separation portion is formed in the cavity to separate both side edges of the inclined portion from other portions. A ceramic package characterized by this.

2. Further comprising a bottom surface portion located at the lowermost layer of the laminate and covering the bottom surface of the cavity, a predetermined region on the bottom surface side of the inclined portion is in planar contact with the bottom surface portion, and a portion of the wiring pattern located in the predetermined region becomes a connection portion with the predetermined component accommodated in the cavity. The ceramic package according to claim 1, characterized by this.

3. The ceramic package according to claim 1 or 2, characterized in that the inclined portion is formed of one layer of ceramic green sheet among the plurality of ceramic green sheets.

4. The ceramic package according to claim 1 or 2, characterized in that the inclined portion constitutes a single inclined portion in the cavity while having the separation portion, or constitutes a plurality of adjacent inclined portions in the inner circumferential direction in the cavity, or constitutes a plurality of opposing inclined portions in the cavity.

5. The inclined portion consists of a first inclined portion and a second inclined portion. The first inclined portion is formed of one layer of ceramic green sheet among the plurality of ceramic green sheets, and the second inclined portion is formed of any one layer of ceramic green sheet other than the one layer among the plurality of ceramic green sheets. The first inclined portion has no said separation portion, and consists of two inclined portions facing each other in a first direction orthogonal to the stacking direction within the cavity. The second inclined portion has no said separation portion, and consists of two inclined portions facing each other in a second direction orthogonal to the first direction within the cavity. The ceramic package according to claim 1 or 2, characterized in that.

6. A method for manufacturing a ceramic package having a cavity for accommodating a predetermined component, a step of preparing a first ceramic green sheet for forming the cavity, a second ceramic green sheet for forming an inclined portion on the inner wall of the cavity, and a third ceramic green sheet for forming the bottom surface of the cavity; a step of forming through holes having different inner diameters for each layer of the first ceramic green sheet according to the inner diameter dimension of the cavity; a step of forming a wiring pattern on the surface of the portion of the second ceramic green sheet that becomes the inclined portion, and forming holes or cuts according to the shape and dimensions of the inclined portion; a lamination step of laminating the first ceramic green sheet having the through holes on the third ceramic green sheet, and laminating the second ceramic green sheet having the wiring pattern and the holes or cuts formed thereon on the laminated first ceramic green sheet to form an uncrimped laminate; a crimping step of applying isotropic pressure to the uncrimped laminate to form an unfired block body having a multilayer structure; a firing step of firing the unfired block body; characterized by comprising In the lamination step, the first ceramic green sheet forms one or more linear side portions of a predetermined length on the inner peripheral edge portion on the opening side of the cavity, and a stepped portion extending from the linear side portion to the bottom surface of the cavity on the inner wall of the cavity. In the crimping step, the second ceramic green sheet forms the inclined portion with the stepped portion as a base, so that the wiring pattern extends from the outer peripheral edge portion on the opening side to the vicinity of the end portion on the bottom surface side of the cavity of the inclined portion, and a separation portion that separates both side edge portions of the inclined portion from other portions is formed within the cavity. A method for manufacturing a ceramic package, characterized in that.

7. A method for manufacturing a ceramic package according to claim 6, characterized in that a wiring pattern and the holes or cuts are formed in a ceramic green sheet selected from the first ceramic green sheet, and the inclined portion is formed on the inner wall of the cavity by the selected ceramic green sheet.

8. An electronic device in which a predetermined component is housed in a cavity having an opening upward in the stacking direction of a ceramic package manufactured by pressing and firing a laminate of a plurality of ceramic green sheets, one or more linear side portions of a predetermined length formed at an inner peripheral edge portion of the opening of the cavity; an inclined portion inclined from the linear side portion toward the bottom surface of the cavity; a wiring pattern formed on a surface of the inclined portion and extending from an outer peripheral edge portion of the opening to a vicinity of an end portion on the bottom surface side of the inclined portion; comprising: the ceramic package has a circuit connection portion enabling electrical connection with other devices between an inner peripheral edge portion and an outer peripheral edge portion of the opening of the cavity, one end of the wiring pattern is connected to the predetermined component, and the other end is connected to the circuit connection portion, and a separation portion is formed in the cavity to separate both side edge portions of the inclined portion from other portions.

9. The electronic device according to claim 8, characterized in that the predetermined component is an electronic component including at least a light emitting diode (LED) and a sensor element.

Images