JP2001185638A - Wiring board of multilayer ceramic structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect ceramic at the side part of a via against cracking or chipping at the time of making a via hole in a green sheet by punching, firing or breaking while reducing the size of a wiring board when a wiring board of multilayer ceramic structure having a via in the sealing face around a recess is produced. SOLUTION: A part of a ceramic layer forming a sealing face 115 is spread onto a face for forming a bonding pad 112 located close to the inner circumference thereof thus forming a wide part 117 and a via 121 is provided therein. Since the via 121 is provided in a wide part and a thickness can be ensured on the via side, troubles are prevented during production and the size of the board is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board having a laminated ceramic structure for an electronic component package, and more particularly, to a SAW filter, a quartz oscillator, a transistor, and an IC.
The present invention relates to a wiring board having a ceramic laminated structure (hereinafter, also referred to as a wiring board or simply a board) used for a package for sealing an electronic component such as an electronic component.

[0002]

2. Description of the Related Art FIGS. 10 to 12 show an example of a wiring board 100 of this type having a ceramic laminated structure, which has a three-layer ceramic structure, has a substantially rectangular shape in plan view, and has a rectangular opening 105 on its upper surface. In the shape of a container with The concave portion 105 is a space for accommodating an electronic component (not shown), and the left and right sides thereof are the lowermost (first layer) ceramic layer 101 forming the bottom surface 107 of the concave portion 105 in a longitudinal sectional view.
It is formed in a step shape from the top to the opening. Then, on the upper surface of the intermediate ceramic layer 102, a shelf (bonding shelf) 110 that is exposed on the inner side
Are formed with a plurality of bonding pads (electrodes for wire bonding) 112.

The uppermost square frame-shaped ceramic layer 1
Reference numeral 03 denotes a predetermined width in the inward and outward directions of the substrate, and the upper surface thereof forms a sealing surface (sealing area) 115.
A metallized layer (not shown) (hereinafter also referred to as a metallized layer for sealing) is formed on the surface. The sealing surface 115 has a metallized layer formed thereon and a die attach surface (a metallized layer formed on the bottom surface 107 of the concave portion).
A suitable number of vias (columnar conductors) 121 are formed to establish conduction (electrical connection) between layers. This wiring board 1
00, after mounting an electronic component chip in the concave portion 105 and performing wire bonding between its electrode and the bonding pad 112, a lid (not shown) is covered so as to cover the concave portion 105; Is hermetically sealed, for example, by soldering.

[0004] This type of wiring board 1 having a ceramic laminated structure
00 indicates that the bonding pad 11
2. A metallized paste mainly composed of a high melting point metal powder is printed for forming a metallized layer for sealing on the sealing surface 115 and a metal layer such as the via 121, and a ceramic formed to have a shape of each layer. Laminate green sheets,
It is manufactured by pressing and then firing. However,
Each ceramic green sheet is usually formed to have a size that allows a large number of substrates to be taken at one time. After laminating and pressing, a dividing groove (break groove) is formed at the boundary of each substrate unit, and firing is performed. After a necessary plating layer is collectively formed later, mass production is performed by dividing (cutting) each substrate unit along the groove.

In order to reduce the installation area of such a wiring board 100 in accordance with the miniaturization of the equipment on which the wiring board 100 is mounted, it is required that the external dimensions (planar dimensions) of the wiring board itself be made as small as possible. I have. Due to such a demand for miniaturization, the width W1 of the sealing surface 115 and the width W2 of the shelf (bonding pad forming surface) 110 are also required to be as narrow as possible without impeding each other. For example, the width W1 of the surface 115 is 0.35 m.
m, the width W2 of the shelf 110 is, for example, 0.25
It has been set to a required minimum minute dimension of about mm.

In the case where a via 121 for providing conduction between layers is provided like the wiring board 100, the via 12
It is necessary to secure a certain width or more of the width WV of the ceramic on the outer side of the ceramics 1 in manufacturing. This is because if the width WV of the ceramic on the side of the via 121 is too narrow, the outside of the via hole may be formed at the time of forming the green sheet, that is, at the time of punching (piercing) for the via hole or at the time of punching into each substrate shape. Is easy to break,
This is because cracks and chips are liable to occur in the same portion even at the time of firing or at the time of a break afterwards, and the product yield is deteriorated. For this reason, conventionally, in the wiring board 100 having the above-described ceramic laminated structure, it has been determined that the ceramic width WV on both sides of the via 121 should be at least about 0.2 mm. On the other hand, the diameter DV of the via 121 needs to be 0.15 mm or more from the viewpoint of processing accuracy and the like. Therefore, in this example, the uppermost ceramic layer 103
When the via 121 is formed in the ceramic layer, the width W1 of the ceramic layer in the inward and outward directions needs to be 0.55 mm or more.

[0007]

That is, from the viewpoint of ensuring airtightness or sealing performance, the ceramic layer 1 forming the sealing surface 115 is not required.
The width W1 in the inward and outward directions of 03 is only required to be about 0.35 mm, whereas when the via 121 is provided in the sealing surface 115, the width W1 needs to be widened by about 0.2 mm, which is the difference. there were. Therefore, in the wiring board 100 having such a ceramic laminated structure, the wiring board has to be enlarged in the width direction by the difference, which is against the demand for miniaturization.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of such a wiring board having a multilayer ceramic structure, and has as its object to provide a wiring board having a multilayer ceramic structure having vias in a ceramic layer forming a sealing surface. It is an object of the present invention to provide a substrate structure that can meet the demand for miniaturization without causing the above-mentioned problem in manufacturing.

[0009]

According to a first aspect of the present invention, there is provided a semiconductor device having a sealing surface on an upper surface around a concave portion for mounting an electronic component. In a wiring board having a ceramic laminated structure, a via is formed in a ceramic layer forming a surface, and a bonding pad is formed along the sealing surface on an upper surface of a ceramic layer below the ceramic layer. The width of the portion of the ceramic layer forming the stop surface is widened toward the bonding pad forming surface side to form a wide portion, and the wide portion is provided with the via. In addition, in this specification, a part is
Refers to part or most.

[0010] In the present invention, the portion of the ceramic layer forming the sealing surface is widened to be wider on the side where the bonding pad is formed in plan view, and the via is provided in the widened portion. Does not cause the above-described manufacturing problems due to the formation of the via hole, and the sealing surface in the portion where the via is not formed can have a necessary minimum width that does not impair the sealing. That is, of the width of the ceramic of the uppermost layer forming the sealing surface where the via is formed, the width of the sealing surface is expanded inward corresponding to the portion where the via is formed. It is possible to reduce the size of the device without causing any manufacturing defects. The bonding pad may be formed along the sealing surface avoiding the wide portion.

According to a second aspect of the present invention, a sealing surface is provided on an upper surface around a concave portion for mounting an electronic component, and a via is formed in a ceramic layer forming the sealing surface. A bonding pad is formed along the sealing surface on the upper surface of the ceramic layer below the ceramic layer, and the upper surface of the ceramic layer below the ceramic layer on which the bonding pad is formed forms a bottom surface of the recess.
In a wiring board having a ceramic laminated structure having more than one layer, the width of the portion of the ceramic layer forming the sealing surface is widened on the side of the bonding pad forming surface and above the ceramic layer on which the bonding pad is formed. And the via is provided in the wide portion.

The wiring board having a ceramic laminated structure according to the present invention can be applied to a wiring board having a plurality of ceramic layers, but the invention according to claim 2 is applied to a wiring board below the ceramic layer on which the bonding pads are formed. The wiring board has a ceramic laminated structure of three or more layers in which the upper surface of the ceramic layer forms the bottom surface of the concave portion.

[0013] In the wiring board having a ceramic laminated structure according to claim 2, an edge near the center of the recess in the wide portion is an edge near the center of the recess in the ceramic layer on which the bonding pad is formed. Preferably, it does not protrude from the edge toward the center of the recess. Further, the wiring board having the ceramic laminated structure in the present invention is generally formed in a substantially rectangular shape in plan view, in which case, the wide portion may be one or more in one side. Good. Furthermore, in order to form vias well,
It is preferable that the wide portion has a width of 0.55 mm or more.

[0014]

1 to 4 show a first embodiment of a wiring board having a ceramic laminated structure according to the present invention.
This will be described in detail with reference to FIG. In the figure, reference numeral 100 denotes a substrate, which has a three-layered ceramic layer (101 to 103) structure and has a container shape. Opposite left and right sides of the concave portion 105 in which the electronic component is accommodated are a bottom surface (die attach surface) 107.
Are formed stepwise upward from the lowermost ceramic layer 101, and the inside of the other two sides forms a wall 109 substantially perpendicular to the bottom surface 107. On the upper surface of the ceramic layer 102 formed on the lowermost ceramic layer 101, a large number of bonding pads (metallized layers) are provided on a shelf (also referred to as a bonding pad forming surface) 110 exposed to the concave portion 105 side. The upper surface of the uppermost square frame-shaped ceramic layer 103 forms a sealing surface 115, on which a sealing metallization layer (not shown) is formed.

On the other hand, in the present embodiment, the left and right sealing surfaces 115 are provided.
Is expanded so as to swell by a predetermined amount H toward the bonding pad forming surface 110 side so that the width W1 of the bonding pad forming surface 110 is widened over a predetermined range S along the circumferential direction of the sealing surface 115 in plan view at appropriate places (two positions in the drawing). And a wide portion 117 is formed. Vias 121 are provided above the lowermost ceramic layer 101 so as to have an upper end on the upper surface of each wide portion 117 and are connected to the metallization layer for sealing. In this embodiment, the inner edge 118 of the wide portion 117 does not protrude from the inner edge 111 of the lower shelf 110 on the center side of the concave portion 105, that is, the shelf 110
Is formed so as to be located slightly outside the inner edge 111 of the. Incidentally, in the present embodiment, the width W1 of the sealing surface 115 is 0.35 mm, the bulging amount H of the wide portion 117 is 0.3 mm,
The diameter DV of the via 121 is set to 0.15 mm.
The widths WV1 and WV2 of the ceramics on both sides are 0.25 mm, respectively. The range S along the circumferential direction of the sealing surface 115 of the wide portion 117 has a size that ensures a sufficient width of the ceramic outside the via 121.

Such a wiring board 100 has a via 12
1. Exposed metallized layers such as a sealing metallized layer (not shown) and other wiring layers are plated with nickel, and the outermost surface is plated with gold. Then, after mounting an electronic component (not shown) and performing wire bonding between the electrode and the bonding pad 112, a lid (not shown) is placed so as to cover the concave portion 105, and for example, soldering is performed on the metallizing layer for sealing. And sealed. The wiring board 100 has a multi-cavity pattern in which a metallization paste is printed on the surface for a metallization layer for sealing or a wiring layer, and the via holes are filled, similarly to a wiring board having a conventional ceramic laminated structure. It is manufactured by laminating and crimping ceramic green sheets, then baking and plating, and then dividing each substrate unit.

In the wiring board 100 of the present embodiment, the proper position (two places) of the sealing surface 115 on the peripheral upper surface is the concave portion 1.
The width of the ceramic material 05 is widened so as to protrude toward the center of the portion 05, and the vias 121 are provided there. Therefore, sufficient ceramic wall widths WV1 and WV2 are secured on both sides of the via 121. On the other hand, the other sealing surface 115 has the width W1.
Are formed to be as narrow as the sealing surface width of the substrate having no via 121. Therefore, when the green sheet is formed in the production, that is, when punching for a via hole for forming the via 121 or when punching into each substrate shape, the width WV is used.
1. There is no sharpness in the portion of WV2. Also, cracking or chipping does not occur at the same portion during firing or subsequent break, so that the product yield is good. in addition,
Despite the presence of via 121 in ceramic layer 103 forming sealing surface 115, wiring substrate 1 without via 121
The same miniaturization as in 00 is achieved. In such a wiring board 100, the wide portion 117 may be designed to be provided on a portion of the shelf where the bonding pad 112 is not provided.

Next, a second embodiment of a wiring board having a ceramic laminated structure according to the present invention will be described in detail with reference to FIGS. However, the wiring board 200 is different from the first embodiment in that the first embodiment is a wiring board having a ceramic three-layer structure, but only in that the ceramic is embodied in a wiring board having a five-layer structure. That is, each of the intermediate ceramic layer 102 and the uppermost ceramic layer 103 in the above-described embodiment has two layers (102a, 102a).
b, 103a, and 103b), which are different only in that they are different from each other and do not differ in operation and effect.
The same portions are denoted by the same reference numerals, and description thereof will be omitted.

Next, a third embodiment of a wiring board having a ceramic laminated structure according to the present invention will be described in detail with reference to FIGS. This wiring board 300 is different from the above-described embodiment in that the wiring board has a ceramic three-layer or five-layer structure, but is different only in a specific example of a ceramic two-layer structure. , The same parts are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

That is, the wiring board 300 of the present embodiment has a ceramic two-layer structure, and has a lower rectangular ceramic layer 301 and a rectangular frame-shaped ceramic layer 30 around the upper surface.
It consists of two. And the lower ceramic layer 301
Is the bottom surface (die attach surface) 107 of the concave portion 105.
The bonding pads 112 are formed on the left and right sides of the periphery. On the other hand, the upper ceramic layer 3
The upper surface of the ceramic layer 302 forms a sealing surface 115, a metallizing layer for sealing is formed, and the width of a part of the ceramic layer 302 is widened so as to bulge into the region where the bonding pad 112 is formed. And via 121 there
Are formed.

In this embodiment, however, there is no independent ceramic layer forming the bonding pad 112 forming surface (bonding shelf) as in the above embodiment, and the electrodes of the electronic components to be mounted and the bonding pads 112 to be wire-bonded are not provided. Differs from the first embodiment only in that it is formed around the bottom surface 107 of the recess 105. That is, conventionally, in such a wiring board, when the via 121 having the upper end portion is provided in the upper ceramic layer forming the sealing surface, the width of the ceramic layer forming the sealing surface where the via 121 is provided is set to the width. The width was constant for the entire side. On the other hand, in the present embodiment, the ceramic layer 3 forming the sealing surface
02 is widened inward to form a wide portion 117, and the wide portion 117 is provided with a via 121. Therefore, as in the above-described embodiment, there is no problem in manufacturing the wiring board 300, and The size can be reduced.
As will be understood from the present embodiment, the wiring board of the present invention can be embodied regardless of the number of ceramic layers constituting the wiring board, as long as the number is plural.

In each of the above embodiments, a part of each of the sealing surfaces (ceramic layers) forming two sides of the four sides in plan view and having a rectangular shape is made wider, If the sealing surface has a bonding pad formation surface, a wide portion can be provided on one side or all sides and a via can be provided there. Further, the number of wide portions provided on the sealing surface along each side may be any. That is,
The number and position of the wide portions may be appropriately designed according to the substrate such as the number or arrangement of vias to be formed. Note that the length of the wide portion (S in FIG. 3) is appropriately set as long as the formation of the bonding pad is not hindered and the width of the via is not cracked from the edge (periphery) of the via. Good. Further, in addition to providing a wide portion on a part of each side, a wide portion (wide side) in which one side is wider than the other side may be formed.

In the above, a case has been described in which the present invention is embodied in a wiring board having a ceramic laminate structure in which a lid is soldered to a metallization layer for sealing on a sealing surface and sealed. It is not limited to the one having the sealing structure. For example, a frame-shaped ring (seal ring) made of an iron-nickel alloy or the like and formed with a nickel-plated layer on the surface of the metallization layer for sealing with a nickel-plated layer is bonded by brazing or the like,
The present invention can be similarly applied to a wiring board having a structure in which a lid is sealed thereon by soldering or the like. The present invention
The present invention is not limited to the structure and shape of each of the above embodiments, and can be embodied by appropriately changing the design without departing from the gist thereof.

[0024]

According to the ceramic laminated wiring board of the present invention, the width of the portion of the ceramic layer forming the sealing surface is widened toward the bonding pad forming surface side to form a wide portion, and a via is provided therein. Therefore, the width of the ceramic wall around (outside) the via can be sufficiently ensured. Therefore, when forming the green sheet in its manufacture,
In other words, it is possible to prevent the occurrence of sharpness outside the via hole at the time of punching for the via hole or punching into each substrate shape. In addition, cracks and chips are prevented from being generated in the same portion during firing and subsequent breaks, so that the product yield can be improved. In addition, despite the presence of vias in the sealing surface, the same miniaturization as a wiring board without vias can be achieved. That is, according to the present invention, even though the wiring board has a ceramic laminated structure having vias on the sealing surface, the size can be reduced without lowering the manufacturing yield, and the wiring board is mounted. There is a remarkable effect that it is possible to respond to the demand for reducing the installation space in such devices.

[Brief description of the drawings]

FIG. 1 is a plan view of a first embodiment of a wiring board having a ceramic laminated structure according to the present invention.

FIG. 2 is an enlarged perspective view of a main part of FIG. 1;

FIG. 3 is an enlarged plan view of a main part of FIG. 1;

FIG. 4 is a sectional view taken along line AA of FIG. 1;

FIG. 5 is a sectional view and an enlarged view of a main part of a second embodiment of the wiring board having a ceramic laminated structure according to the present invention.

FIG. 6 is an enlarged perspective view of a main part of FIG. 5;

FIG. 7 is a plan view of a third embodiment of a wiring board having a ceramic laminated structure according to the present invention.

FIG. 8 is an enlarged perspective view of a main part of FIG. 7;

FIG. 9 is a sectional view taken along line BB of FIG. 7;

FIG. 10 is a cross-sectional view of a conventional wiring board having a ceramic laminated structure.

FIG. 11 is a plan view of the wiring board having the ceramic laminated structure of FIG. 10;

FIG. 12 is a partially enlarged plan view of the wiring board having the ceramic laminated structure of FIG. 10;

[Explanation of symbols]

100, 200, 300 Wiring board 103, 103b, 302 having a laminated ceramic structure Ceramic layers 101, 102, 102a to 103a, 301 forming a sealing surface Ceramic layer lower than the ceramic layer forming a sealing surface 105 For mounting electronic components Concave portion 107 Bottom surface of concave portion 112 Bonding pad 115 Sealing surface 117 Wide portion 121 Via

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Claims (3)

[Claims] 1. A semiconductor device according to claim 1, wherein a sealing surface is provided on an upper surface around the concave portion for mounting the electronic component, a via is formed in a ceramic layer forming the sealing surface, and a ceramic layer below the ceramic layer is formed. In a wiring board having a ceramic laminated structure in which bonding pads are formed along the sealing surface on the upper surface, the width of the ceramic layer forming the sealing surface is increased toward the bonding pad formation surface side. A wiring board having a ceramic laminated structure, wherein said wiring board has a wide portion and said via is provided in said wide portion. 2. A method according to claim 1, further comprising: forming a sealing surface on the upper surface around the concave portion for mounting the electronic component, forming a via in the ceramic layer forming the sealing surface, and forming a ceramic layer below the ceramic layer. A wiring board having a ceramic laminated structure of three or more layers, wherein a bonding pad is formed along the sealing surface on the upper surface, and an upper surface of a ceramic layer below the ceramic layer on which the bonding pad is formed forms a bottom surface of the concave portion; In the above, the width of the portion of the ceramic layer forming the sealing surface is expanded on the ceramic layer on which the bonding pad is formed on the bonding pad forming surface side to form a wide portion, and the via is formed in the wide portion. A wiring board having a ceramic laminated structure, wherein the wiring board is provided. 3. An edge near the center of the concave portion of the wide portion does not project toward the center of the concave portion from an edge near the center of the concave portion of the ceramic layer on which the bonding pad is formed. 3. The wiring board according to claim 2, wherein the wiring board has a ceramic laminated structure.