JP2017076698A - Wiring board and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board which includes wiring layers formed on a surface of a substrate body made of ceramic and a pad connected with the wiring layer on one end side, and in which a gap is not formed between ceramic layers and the size of the pad can be set with freedom; and provide a manufacturing method of the wiring board.SOLUTION: A wiring board 1 comprises: a substrate body 2 which is made of ceramic c1 and has a pair of opposite surfaces 3, 4; wiring layers 10, 14 formed along the one surface 3 of the substrate body 2; and a pad 9 which is formed on the one surface 3 of the substrate body 2 and connected with the wiring layers 10, 14, in which the bottom side of each of the wiring layers 10, 14 is embedded inside the substrate body 2 than the surface 3 of the substrate body 2, and the pad 9 partially overlaps part of the wiring layers 10, 14 and a thickness of the pad 9 is thicker than that of en exposed portion of the wiring layers 10, 14 on the surface 3 side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wiring board having a wiring layer and pads connected to the wiring layer on at least one surface of a substrate body made of ceramic, and a method for manufacturing the same.

For example, in order to improve moisture resistance and water resistance and reduce contact resistance between a wiring pattern and a coated conductor (corresponding to a pad) covering its terminal portion, a substrate made of ceramic or the like and silver formed on the surface of the substrate A wiring board including a wiring pattern including particles, and a coated conductor formed on a terminal portion located at one end of the wiring pattern, covering the terminal portion and having a flat surface including carbon, and a manufacturing method thereof are proposed. (For example, refer to Patent Document 1).
By the way, the entire laminate of a flat ceramic layer and a ceramic layer having a rectangular frame shape in plan view has a box-shaped substrate body, and a crystal resonator is mounted on the bottom surface of a cavity provided in the substrate body. In the case of a ceramic package having a pair of pads for wiring and a wiring layer having one end connected to each pad, a part of the wiring layer is formed on the ceramic layer in order to meet the demand for miniaturization and low profile. May enter. Furthermore, it is necessary to form the pad high in order to secure a vibration space for the crystal resonator.

However, when the wiring layer including the pad is printed and formed with a relatively thick metallized layer of one step, when a part of the metallized layer enters between the ceramic layers, the ceramic layer adjacent to the entering part Since voids are formed between them, the sealing performance of the cavities may be impaired.
On the other hand, after the wiring layer is printed and formed with a relatively thin metallized layer, only the pad is further printed on the upper surface of one end of the wiring layer. In some cases, the size and type of the crystal resonator to be mounted on the pad are limited.

JP-A-2005-109312 (pages 1 to 9, FIGS. 1 to 3)

  The present invention solves the problems described in the background art, and includes a wiring layer formed on at least one surface of a substrate body made of ceramic, and a pad having one end connected to the wiring layer. It is an object of the present invention to provide a wiring board in which no gap is formed and the size of the pad can be freely set and a method for manufacturing the wiring board.

Means for Solving the Problems and Effects of the Invention

In order to solve the above-mentioned problems, the present invention embeds the bottom of the wiring layer formed on the surface of the substrate body made of ceramic inside the surface and prints a pad overlapping with a part of the wiring layer. It was designed with the idea in mind.
That is, the wiring board according to the present invention (Claim 1) is made of ceramic and has a pair of opposing substrate bodies, a wiring layer formed along at least one surface of the substrate body, and the substrate body. A wiring board formed on the one surface of the substrate and connected to the wiring layer, wherein the bottom side of the wiring layer is closer to the inside of the substrate body than the surface of the substrate body. The pad is embedded, and part of the pad overlaps with part of the wiring layer in plan view, and the thickness of the pad is thicker than the exposed part on the surface side of the wiring layer. And

According to this, the following effects (1) and (2) can be achieved.
(1) Since the thickness of the exposed portion of the wiring layer on the surface of the substrate body is relatively thin without reducing the cross-sectional area of the wiring layer, a part of the wiring layer is overlapped and connected to the wiring layer. The height of the pad can be made relatively high and the upper surface thereof can be made relatively flat. Therefore, for example, it is possible to easily secure an operation space of a crystal resonator mounted on the pad, and to accurately mount an electronic component such as a crystal resonator or a semiconductor element on the pad.
(2) Since the area of the pad in plan view can be set freely, the size and type of the crystal resonator and electronic components to be mounted are not easily limited by the size of the pad.

The ceramic is a high-temperature fired ceramic such as alumina, mullite, or aluminum nitride, or a low-temperature fired ceramic such as glass-ceramic.
Further, the substrate main body may be in a form composed of a single ceramic layer or a form in which a plurality of ceramic layers are laminated.
Furthermore, the pair of surfaces are relative names, and for example, one can be referred to as a surface and the other as a back surface.
The wiring layer and the pad are mainly made of W or Mo when the ceramic is a high-temperature fired ceramic, and mainly made of Cu or Ag when the ceramic is a low-temperature fired ceramic.
Furthermore, the pad has a rectangular shape that is approximate to a square in plan view, a regular polygon shape that is a pentagon or more, or a circular shape, and one end or a part of the periphery thereof and a tip portion of the wiring layer formed in a predetermined pattern ( Are partially overlapped with each other in plan view.
In addition, a plurality of sets of the plurality of wiring layers and pads may be formed for each pair of surfaces of the substrate body.

According to the present invention, there is provided a wiring in which at least one surface of the substrate body is erected along the periphery of the surface and a side wall surrounding at least a part of the wiring layer and the pad is formed. A substrate (claim 2) is also included.
According to this, since a cavity having such a surface as the bottom surface is formed on at least one surface side of the substrate body, the following effects (3) and (4) can be achieved.
(3) A part of the wiring layer enters between the flat ceramic layer including the surface serving as the bottom surface of the cavity and the rectangular frame-shaped ceramic layer forming the side wall laminated around the ceramic layer. Even so, it is difficult for voids to be formed between the ceramic layers adjacent to the entry portion. Therefore, it becomes possible to ensure the sealing performance in the cavity in which a crystal resonator or the like is mounted later.
(4) Since the position of the pad in plan view can be set relatively freely, a gap can be easily set between the pad and the inner wall surface of the cavity. Therefore, it is possible to accurately perform image processing when a crystal resonator or electronic component is mounted.
The side wall may be formed on both of the pair of surfaces of the substrate body to constitute a wiring board having a pair of opposed cavities.

  On the other hand, a method for manufacturing a wiring board according to the present invention (Claim 3) comprises a substrate body made of ceramic and having a pair of opposed surfaces, a wiring layer formed along at least one surface of the substrate body, A method of manufacturing a wiring board comprising a pad formed on the one surface of the substrate body and connected to the wiring layer, wherein a conductive paste containing metal powder is printed on a surface of a green sheet A step of forming an unfired wiring layer, and pressing the surface of the green sheet including the unfired wiring layer along the thickness direction of the green sheet, thereby forming a bottom portion of the unfired wiring layer. A step of embedding a side of the green sheet inward of the green sheet, and a surface of the green sheet that is partially overlapped with a part of the unfired wiring layer in plan view. A conductive paste containing powder was printed thicker than the exposed portion of the surface side of the unfired wiring layer, and forming a bad unfired, and characterized in that.

According to this, by going through the three steps, it becomes possible to reliably manufacture the wiring board having the effects (1) and (2) by relatively few and simple steps (effect ( 5)).
The step of forming the unfired wiring layer and pad is performed by screen printing a conductive paste containing a metal powder such as W on a predetermined position on the surface of the green sheet.
Further, after the step of forming the unfired pad, a step of simultaneously firing the green sheet, the wiring layer, the pad, and the like is performed.

Further, after the step of forming the bud, the side wall is formed by laminating a frame-like green sheet having a similar shape to the outer shape in plan view on the periphery of the surface of the green sheet. In addition, the step of providing a cavity having the surface as the bottom surface and the co-firing step may be performed thereafter.
Further, after the co-firing step, a step of coating a metal plating film (for example, Ni plating film and Au plating film) on the surface of the wiring layer and the pad exposed to the outside is performed.
In addition, each of the steps may be performed in a multi-cavity form.

The perspective view which shows the wiring board of one form by this invention. (A) is a top view in the position (surface of a substrate main body) along the arrow of the AA line in FIG. 1, (B) is the partial perpendicular along the arrow of the BB line in (A). Sectional drawing. FIG. 3 is a vertical sectional view taken along the line CC in FIG. 1 and FIG. (A) thru | or (D) are schematic which shows each manufacturing process of a 1st wiring board. Schematic which shows the manufacturing process following FIG.4 (D). FIG. 4 is a vertical sectional view similar to FIG. 3 showing an application form of the wiring board. The top view which shows the wiring board of a different form in this invention. FIG. 8 is a vertical sectional view taken along line XX in FIG. 7.

Hereinafter, modes for carrying out the present invention will be described.
FIG. 1 is a perspective view showing a wiring board 1 according to an embodiment of the present invention, and FIG. 2A is a plan view at a position (surface 3 of the board body 2) along the line AA in FIG. , (B) is a partial vertical sectional view taken along the line BB in (A), and FIG. 3 is taken along the line CC in FIG. 1 and FIG. 2 (A). It is a vertical sectional view.
As shown in FIGS. 1 to 3, the wiring board 1 includes a substrate body 2 having a front surface 3 and a back surface (front surface) 4 facing each other in a rectangular (rectangular) shape in plan view, and a predetermined along the front surface 3. Two wiring layers 10 and 14 formed in a pattern; a pair of pads 9 formed on the surface 3 and partially connected to the wiring layers 10 and 14; and a surface 3 of the substrate body 2 A side wall 6 is provided which is provided along the periphery and has a rectangular frame shape in plan view and surrounds most (a part) of the pair of pads 9 and the wiring layers 10 and 14.
The substrate body 2 is made of a flat ceramic layer c1, and the side wall 6 made of the ceramic layer c2 is integrally laminated along the periphery of the surface 3 thereof. The ceramic layers c1 and c2 are mainly composed of alumina, for example.

Further, as shown in FIGS. 1, 2 (A), and 3, the side wall 6 has a rectangular parallelepiped shape as a whole with the inner surface 8 of the four sides positioned inside thereof and the surface 3 of the substrate body 2 as the bottom surface. A cavity 7 is formed.
Furthermore, the substrate body 2 and the side wall 6 have side surfaces 5 for each of the four sides in plan view, and concave surfaces 5a whose plan view is recessed in an arc shape are formed at the four corners located between the side surfaces 5. Yes. A concave conductor 17 having a similar shape in plan view is formed on the concave surface 5a, and the upper end portion of the concave conductor 17 is a sealing formed in a rectangular frame shape in plan view formed on the entire top surface of the side wall 6. The conductor layer 18 is individually connected. The lower end portion of the concave conductor 17 is individually connected to four connection terminals 19 formed on the four corners of the back surface 4 of the substrate body 2.
The pad 9, the wiring layers 10, 14, the concave conductor 17, the sealing conductor layer 18, and the connection terminal are made of, for example, W or Mo.

  The one wiring layer 10 is formed linearly along the inner wall surface 8 of one long side of the side wall 6 in plan view, as shown in FIGS. 1, 2A, and 2B. The connecting conductor 13 is connected to the concave conductor 17 via the connecting conductor 13 located on the base end side, and has a connecting portion 12 extending obliquely toward the center side of the surface 3 on the tip end side. Further, the outer side in the width direction of the wiring layer 10 enters between the ceramic layers c1 and c2, and in the middle of the outer side, there is a plating wiring 11 in which the end surface is exposed on the adjacent side surface 5. Have. As shown in FIG. 2B, the wiring layer 10 including the plating wiring 11, the connection portion 12, and the connection conductor 13 has a bottom side closer to the inside of the ceramic layer c 1 than the surface 3 of the substrate body 2. It is buried to be located.

The wiring layer 10 has a thickness of about 5 to 10 μm, and the depth of the wiring layer 10 on the bottom side embedded in the ceramic layer c1 is about 3 to 6 μm. That is, the thickness of the wiring layer 10 exposed on the surface 3 is about 2 to 4 μm. In addition, no gap is formed in the vicinity between the ceramic layers c1 and c2 into which the outer side in the width direction of the wiring layer 10 enters.
The connection portion 12 located on the distal end side of the wiring layer 10 overlaps with a part (corner portion) of the pad 9 in plan view. The pad 9 has a square shape in plan view and a quadrangular pyramid shape as a whole, and a thickness of about 15 to 40 μm. That is, the thickness of the pad 9 is larger than the thickness of the wiring layer 10.

  Further, as shown in FIGS. 2A and 2B, the other wiring layer 14 is formed linearly along the inner wall surface 8 of the other long side of the side wall 6 in plan view, and its base end. It is connected to a concave conductor 17 different from that described above via a connection conductor 13 different from that described above, and has a flat trapezoidal connection portion 16 in plan view on its inner side. Further, the outer side in the width direction of the wiring layer 14 enters between the ceramic layers c1 and c2, and the plating wiring 15 whose tip surface is exposed on the adjacent side surface 5 is provided at the tip of the outer side. Have. The wiring layer 14 including the plating wiring 15, the connecting portion 16, and the connecting conductor 13 also has a ceramic layer c 1 at the bottom side of the substrate rather than the surface 3 of the substrate body 2, as shown in FIG. It is buried so as to be located inside.

The thickness of the wiring layer 14 and the depth on the bottom side embedded in the ceramic layer c1 are the same as the thickness of the wiring layer 10 and the depth of embedded. Therefore, no gap is formed in the vicinity of the ceramic layers c1 and c2 into which the outer side in the width direction of the wiring layer 14 enters.
The plating wiring 15 is connected to the plating wiring 11 of the adjacent wiring board 1 and used for electrolytic metal plating when a large number of the wiring boards 1 are manufactured.
The connection part 16 of the wiring layer 14 overlaps with a part (one side part) of the pad 9 different from the above in plan view. The pad 9 has the same shape and thickness as described above.

Further, as shown in FIG. 1, the pair of pads 9 have a square shape in plan view and an overall quadrangular pyramid shape, and as shown in FIG. It is formed at a position away from.
In the wiring board 1 as described above, after a crystal resonator (not shown) is mounted on each upper surface of the pair of pads 9 via a pair of electrodes located on the base end side, A metal lid (not shown) is joined to the upper surface of the conductor layer 18 by seam welding or brazing. As a result, a vibration space of the crystal resonator is secured, and the inside of the cavity 7 including the crystal resonator can be reliably sealed from the outside.
According to the wiring board 1 having the configuration and structure as described above, the effects (1) to (4) as described above can be reliably achieved.

Below, the manufacturing method of the said wiring board 1 is demonstrated.
A ceramic slurry is prepared by blending appropriate amounts of alumina powder, binder resin, solvent, plasticizer, etc. in advance, and the slurry is formed into a sheet by the doctor blade method, so that two pieces are for taking a large number of pieces. Ceramic green sheets (hereinafter, simply referred to as green sheets) g1 and g2 were prepared.
First, as shown in FIG. 4 (A), a plurality of product areas pa having a rectangular shape in plan view to be the ceramic layer c1 are partitioned for one green sheet g1 having the front surface 3 and the back surface 4 facing each other. The virtual scheduled cutting plane cf is set along the length and breadth so as to have a lattice shape in plan view. A known punching process using a punch and a die was performed near each intersection where the planned cutting surfaces cf intersect each other vertically and horizontally to individually form through-holes 20 having a circular cross section.

Next, the surface 3 in each product area pa of the green sheet g1 is screen-printed with a conductive paste containing W powder or Mo powder, and has a predetermined pattern as shown in FIG. An unfired wiring layer 10 having a thickness of about 6 to 12 μm and an unfired wiring layer 14 (not shown) were formed at the same time. The wiring layers 10 and 14 include the connection portions 12 and 16, the connection conductor 13, and the plating wirings 11 and 15. At this time, the plating wires 11 and 15 in the product areas pa adjacent in the front-rear direction in the drawing are connected to each other.
Next, as shown by the white arrow in FIG. 4B, the whole surface 3 of the green sheet g1 having the unfired wiring layer 10 (14) is substantially uniform along the thickness direction. Pressing by pressure was performed. As a result, as shown in the drawing, the bottom side of the unfired wiring layer 10 (14) was buried at a depth of about 3 to 6 μm inside the surface 3 of the green sheet g1.

Further, as shown in FIG. 4B, the same conductive paste is screen-printed around the opening of each through-hole 20 on the back surface 4 of the green sheet g1, and the through-hole 20 is cornered. An unfired connection terminal 19 having a predetermined pattern was formed for each product area pa facing the part.
Next, as shown in FIG. 4C, the same conductive paste as described above is screen-printed above the connection portion 12 of the wiring layer 10 and the connection portion 16 of the wiring layer 14 (not shown). The unfired pad 9 was formed so as to be higher (thicker) than the wiring layer 10 (14) so as to partially overlap each other in plan view.

  In parallel, the same cutting scheduled surface cf is set on the other green sheet g2 and the same through-hole 20 is formed, and at the center of each product area pa adjacent vertically and horizontally in plan view. Punching was performed to form a through-hole (not shown) having a rectangular shape in plan view and having four side walls 8. Subsequently, the same conductive paste is screen-printed on the entire surface of the green sheet g2 that surrounds the through-holes arranged in a lattice shape in plan view and excludes the through-holes 20, thereby providing a flat surface. An unfired conductor layer 18 having a rectangular frame shape for each product area pa was formed.

  Next, as shown in FIG. 4 (D), the green sheet g2 was laminated on the surface 3 of the green sheet g1 so that the respective cut scheduled surfaces cf coincided with each other and pressed. As a result, a cavity 7 comprising the bottom surface (3) and the four inner wall surfaces 8 was formed for each product area pa, with the front surface 3 of the green sheet g1 being the bottom surface. At this time, the outer sides of the wiring layers 10 and 14 entered between the green sheets g1 and g2, but a gap was formed between the green sheets g1 and g2 adjacent to the outside of the entry portion. There wasn't.

Subsequently, in the laminated green sheets g1 and g2, the same conductive paste is applied while sucking along the inner peripheral surface of each of the through holes 20 communicating with each other, and the whole exhibits a cylindrical shape. An unfired cylindrical conductor 17a was formed.
Next, the laminate of green sheets g1 and g2 was baked by heating and holding the laminate of green sheets g1 and g2 in a required temperature range.
As a result, as shown in FIG. 5, the green sheets g1 and g2 become ceramic layers c1 and c2 that are integrally laminated with each other, and the pads 9, the wiring layers 10 and 14, the cylindrical conductor 17a, and the conductor layers. 18 and the connection terminal 19 were also fired at the same time.
In addition, before the said green sheets g1 and g2 are pressure-bonded, the same conductive paste may be applied while sucking along the inner peripheral surfaces of these through holes 20.

  Furthermore, in the state which contacted each electrode pin (all not shown) for every some electrode for plating previously formed in the ear | edge part (discard allowance) which is located in the circumference | surroundings of the said ceramic layers c1 and c2. Electrolytic Ni plating and electrolytic Au plating were performed in which the laminate of the ceramic layers c1 and c2 was sequentially immersed in an electrolytic Ni plating bath and an electrolytic Au plating bath (both not shown). As a result, the laminated body of the ceramic layers c1 and c2 has a required thickness on the surface of the pad 9, the wiring layers 10 and 14, the cylindrical conductor 17a, the conductor layer 18, and the connection terminal 19 exposed to the outside. A Ni plating film and an Au plating film (both not shown) were coated.

Finally, a cutting process was performed in which a disk-shaped blade (not shown) that rotates at high speed along the thickness direction along the planned cutting surface cf of the ceramic layer c1, c2 laminate was performed. At this time, the cylindrical conductor 17 a was divided into four concave conductors 17. As a result, a plurality of the wiring boards 1 shown in FIGS. 1 to 3 could be obtained.
According to the manufacturing method as described above, the plurality of wiring boards 1 can be reliably manufactured by relatively few and simple processes (effect (5)).

FIG. 6 is a vertical sectional view similar to FIG. 3 showing a wiring board 1 a which is an application form of the wiring board 1.
As shown in FIG. 6, the wiring board 1a has the same two wiring layers 10 (14) that are formed in a predetermined pattern along the front surface 3 and the back surface 4 thereof. ), And a pair of upper and lower pads 9 that are partially connected for each connection portion 12 of the wiring layer 10 (14), and the periphery of the front surface 3 and the back surface 4 of the substrate body 2. And a side wall 6a, 6b surrounding the center side (part) of the pad 9 and the wiring layers 10, 16 in a rectangular frame shape.
That is, the wiring board 1a has a pair of upper and lower sides formed by the bottom surface (3, 4) and the inner wall surfaces 8 of the side walls 6a, 6b above and below the substrate body 2 with the front surface 3 or the back surface 4 as a bottom surface. Cavities 7a and 7b.

Further, a sealing conductor layer 18 having a rectangular frame shape in plan view is individually formed on the entire top surface of each of the side walls 6a and 6b. The substrate body 2 and the upper and lower side walls 6 are integrally laminated with ceramic layers c1 to c3 constituting each of them. In addition, a concave conductor 17 similar to that described above is formed at each corner between the four side surfaces 5 made of the ceramic layers c1 to c3, and any one of the concave conductors 17 includes the wiring layer 10 (14). Connecting conductors 13 are connected.
The effects (1) to (4) as described above can also be achieved by the wiring board 1a having the above configuration and structure.
The wiring board 1a is different from the manufacturing method of the wiring board 1 in that a step of forming the wiring layer 10 (14) and the pad 9 on the back surface 4 side of the substrate body 2 and a ceramic layer c3 serving as the side wall 6 It can be easily manufactured by further adding a lamination process or the like.

FIG. 7 is a plan view showing a wiring board 21 of a different form, and FIG. 8 is a vertical sectional view taken along the line XX in FIG.
As shown in FIGS. 7 and 8, the wiring substrate 21 is formed by laminating ceramic layers (ceramics) c <b> 1 to c <b> 3 and has a square (rectangular) shape in plan view and a front surface 23 and a back surface (front surface) 24 that face each other. A substrate body 22 having four wiring layers 26 along two diagonal directions formed on the surface 23 of the substrate body 22 and intersecting each other on the surface 23, and the center of the surface 23 for each wiring layer 26. And four pads 30 having the same shape as described above and individually connected to the end portions on the side.
As shown in FIG. 8, the bottom side of the four wiring layers 26 is embedded in the substrate body 22 rather than the surface 23 of the substrate body 22.

As shown in FIGS. 7 and 8, a concave surface 25a similar to the above is formed at each corner between the four side surfaces 25 of the substrate body 22. A concave conductor 27 having a similar shape in plan view is formed for each concave surface 25a, and the upper ends of the concave conductors 27 are individually connected to the peripheral portions of the four wiring layers 26. Are connected individually to four connection terminals 29 formed on the four corners of the back surface 24 of the substrate body 22.
Furthermore, as shown in FIG. 8, conductor layers 31 and 32 having a predetermined pattern are formed between the ceramic layers c1 to c3 constituting the substrate body 22, and the conductor layers 31 and 32 are formed of ceramic layers c1 to c3. Through the via conductors 33 penetrating individually, the pads 30 and the connection terminals 28 formed on the relatively center side of the back surface 24 of the substrate body 22 can be electrically connected.
As shown in FIG. 8, an electronic component 34 such as a semiconductor element is mounted on the four pads 30 via a brazing material (not shown).

The ceramic layers c1 to c3 constituting the substrate body 22 are mainly composed of alumina, and the wiring layer 26, the concave conductor 27, the connection terminals 28 and 29, the pads 30, the conductor layers 31 and 32, and the via conductor 33. Consists of W or Mo. The wiring layer 26 has a thickness of about 5 to 10 [mu] m and a depth embedded in the substrate body 22 of about 3 to 6 [mu] m. Further, the pad 30 has a square shape and a quadrangular pyramid shape having four arcuate portions in plan view, and has a thickness of about 15 to 40 μm.
The wiring substrate 21 as described above is formed by printing an unfired wiring layer 26 on the surface 23 of the green sheet that will be the ceramic layer c3 later, and pressing the surface 23 including the unfired wiring layer 26 in the same manner as described above. Then, each step of individually printing and forming unfired pads 30 so as to partially overlap each other in a plan view is performed at the center-side end portion of each unfired wiring layer 26 in the same manner as described above. Can be manufactured.

The effects (1) to (4) as described above can also be achieved by the wiring board 21 having the configuration and structure as described above.
The substrate body 22 may be formed of only the ceramic layer c3 and the conductor layers 31 and 32 may be omitted.

The present invention is not limited to the embodiments described above.
For example, the ceramic layers c1 to c3 may be a high-temperature fired ceramic such as mullite or aluminum nitride, or a low-temperature fired ceramic such as glass-ceramic. In the latter case, Cu, Ag, or the like is applied to each of the conductors such as the wiring layers 10, 14, 26 and the pads 9, 30.
The pads 9 and 30 may have a rectangular shape, a circular shape, an elliptical shape, or an oval shape in plan view.
Further, the wiring boards 1 and 1a may be configured such that the wiring layers 10 and 14 are not in contact with the inner wall surface 8 (of the cavity 7) of the side wall 6.
Further, the wiring board 21 is formed by laminating side walls having a square (rectangular) frame shape in plan view along the peripheral portion of the surface 23 of the board body 22 so that the four inner wall surfaces of the side walls and the surface 23 are formed. It is good also as a form which formed the cavity used as a bottom face.
In addition, the wiring boards 1a, 1b, and 21 are in a mode that is flush with the surfaces 3 and 23 of the wiring layers 10, 14, and 26. It is good also as a form embedded in.

  According to the present invention, a wiring layer formed on the surface of a substrate body made of ceramic and a pad having one end connected to the wiring layer, no gap is formed between the ceramic layers, and a pad is formed. It is possible to reliably provide a wiring board and a manufacturing method thereof in which the size of the wiring board can be freely set.

1, 1a, 21 ... Wiring board 2, 22 ... ... Board body 3, 23 ... ... Front side 4, 24 ... ... Back side (front side)
6, 6a, 6b …… Side wall 9, 30 ………… Pad 10, 14, 26… Wiring layer c1 to c3 …… Ceramic layer (ceramic)
g1, g2 ………… Green sheet

According to the present invention, there is provided a wiring in which at least one surface of the substrate body is erected along the periphery of the surface and a side wall surrounding at least a part of the wiring layer and the pad is formed. A substrate (claim 2) is also included.
Further, in the present invention, a part of the wiring layer is formed between a flat ceramic layer including the surface and a rectangular frame-shaped ceramic layer formed around the ceramic layer and surrounding the side wall. A wiring board (claim 3) is also included .
According to these, at least one surface side of the substrate main body, since the cavity to such a surface and the bottom surface is formed, the following effects (3), it is possible to obtain the (4).
(3) A part of the wiring layer enters between the flat ceramic layer including the surface serving as the bottom surface of the cavity and the rectangular frame-shaped ceramic layer forming the side wall laminated around the ceramic layer. Even so, it is difficult for voids to be formed between the ceramic layers adjacent to the entry portion. Therefore, it becomes possible to ensure the sealing performance in the cavity in which a crystal resonator or the like is mounted later.
(4) Since the position of the pad in plan view can be set relatively freely, a gap can be easily set between the pad and the inner wall surface of the cavity. Therefore, it is possible to accurately perform image processing when a crystal resonator or electronic component is mounted.
The side wall may be formed on both of the pair of surfaces of the substrate body to constitute a wiring board having a pair of opposed cavities.

On the other hand, a method for manufacturing a wiring board according to the present invention (Claim 4 ) comprises a substrate body made of ceramic and having a pair of opposed surfaces, a wiring layer formed along at least one surface of the substrate body, A method of manufacturing a wiring board comprising a pad formed on the one surface of the substrate body and connected to the wiring layer, wherein a conductive paste containing metal powder is printed on a surface of a green sheet A step of forming an unfired wiring layer, and pressing the surface of the green sheet including the unfired wiring layer along the thickness direction of the green sheet, thereby forming a bottom portion of the unfired wiring layer. A step of embedding a side of the green sheet inward of the green sheet, and a surface of the green sheet that is partially overlapped with a part of the unfired wiring layer in plan view. And printing a conductive paste containing a metal powder thicker than the exposed portion on the surface side of the unfired wiring layer to form an unfired pad.

Claims (3)

A substrate body made of ceramic and having a pair of opposed surfaces;
A wiring layer formed along at least one surface of the substrate body;
A wiring board comprising: a pad formed on the one surface of the substrate body and connected to the wiring layer;
The bottom side of the wiring layer is embedded in the substrate body rather than the surface of the substrate body,
The pad partially overlaps with a part of the wiring layer in plan view, and the thickness of the pad is thicker than the exposed portion on the surface side of the wiring layer.
A wiring board characterized by that. On at least one surface of the substrate body, a side wall is formed so as to stand along the periphery of the surface and surround at least a part of the wiring layer and the pad.
The wiring board according to claim 1. A substrate body made of ceramic and having a pair of opposing surfaces; a wiring layer formed along at least one surface of the substrate body; and the wiring layer formed on the one surface of the substrate body; A wiring board comprising a connected pad, comprising:
Printing a conductive paste containing metal powder on the surface of the green sheet to form an unfired wiring layer;
By pressing the surface of the green sheet including the unfired wiring layer along the thickness direction of the green sheet, the bottom side of the unfired wiring layer is located inside the green sheet from the surface of the green sheet. A process of embedding in
The conductive paste containing the metal powder is placed on the surface of the green sheet at a position where a part of the green sheet overlaps with a part of the unfired wiring layer in plan view than the exposed part on the surface side of the unfired wiring layer. Printing thick and forming an unfired pad,
A method for manufacturing a wiring board.

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