JP2001015915A - Production of wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a wiring board by which dropping of a conductor paste is prevented when it is given to a space for forming an in-layer wiring and the production step is simplified, in a ceramic laminated board having an in-layer wiring for reducing resistance in the wiring. SOLUTION: First green sheets 121 and 131 where a first through hole 4a is formed, and second green sheets 122 and 132 where a second through hole 5a having a smaller opening than the first through hole 4a is formed, are laminated, and both through holes are made integral, thereby forming a space 3 for forming an in-layer wiring. Then, a through hole 2 and the space 3 are filled with a conductor paste 7, and the conductor paste 7 is printed over the surface of green sheets 11 to 14. Then, all green sheets 11 to 14 are laminated and baked to make a wiring board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a wiring board having an in-layer wiring for reducing wiring resistance and used for a hybrid IC or the like.

[0002]

2. Description of the Related Art In general, as a wiring board (thick film circuit board) used for a hybrid IC or the like, a laminated board is used for a circuit board having a large circuit scale or requiring a small size. Among them, the alumina laminated substrate has an advantage that it can be manufactured at low cost. However, the alumina laminated substrate has a drawback that the electric resistance is high because the wiring in the inner layer is made of a material containing W (tungsten) or Mo (molybdenum) as a main component.

Therefore, a method has been devised in which an in-layer wiring space is formed in an insulating layer and this space is filled with a conductive paste as disclosed in Japanese Patent Application Laid-Open No. Hei 5-21635. A general method of manufacturing a wiring board having such an in-layer wiring space is shown in FIGS. 6 and 7 as schematic sectional process drawings. The details of this step will be described below with reference to FIGS. In FIG. 6, T / H indicates a through hole.

First, as shown in FIG. 6 (a), green sheets J11 to J14 of an appropriate size are prepared for the required number of layers (here, four layers), and the green sheets J11 to J14 are formed by punching using a die or the like. A hole J2 and an in-layer wiring space J3 are formed. Next, the conductive paste J4 is filled into the through-hole J2 by a method such as screen printing (FIG. 6B).
Thereafter, as shown in FIG. 6C, each sheet J11, J1
4, a conductor paste J4 is printed in a predetermined pattern.
At this time, the sheet J12 on which the in-layer wiring space J3 is formed,
J13 is not printed in this step. Next, FIG.
As shown in the figure, the sheet from the lowermost sheet J14 to the sheet J13 in which the in-layer wiring space J3 is formed are stacked. And
The in-layer wiring space J3 in the laminated sheet J13 is filled with the conductive paste J4 by screen printing or the like to form the in-layer wiring J5 (FIG. 6E).

From above, a conductor pattern is printed in the same manner as in the step shown in FIG. 6C (FIG. 7A). Subsequently, the sheet up to the sheet J12 on which the in-layer wiring space J3 is formed is laminated (FIG. 7B), and the in-layer wiring space J3 is filled (FIG. 7B).
(C)) and conductor printing (FIG. 7 (d)) are carried out in the same manner as described above. Here, as the conductor paste J4, a paste containing W or Mo as a main component can be used.

In this example, since there were two green sheets J12 and J13 on which the in-layer wiring J5 was formed, the steps of lamination, filling of the in-layer wiring space J3, and conductor printing were repeated twice. If the number of formed green sheets is n, it is necessary to repeat at most n times. After that, the remaining sheets J11 are laminated and fired at a temperature of about 1600 ° C. to complete the wiring board.

[0007]

Here, in the step of filling the wiring space J3 in the layer with the conductor paste J4, as shown in FIG. 8, paper or the like for preventing the adhesion of the conductor paste J4 on the stage J6 is used. In this state, the squeegee J9 is moved in the direction of arrow A in FIG. 8 by screen printing, and the conductive paste J4 is printed with the green sheet J1 and the pattern mask J8 sequentially arranged thereon. When the green sheet J1 is lifted from the printing stage J6 after filling, the conductive paste J
4 hangs downward (in the direction of arrow B in FIG. 8). Therefore, in order to form this structure, as shown in FIG. 6, another green sheet J14 as a receiving tray is laminated below the green sheet J13 in which the in-layer wiring space J3 is formed in advance ( (FIG. 6 (d))
Thereafter, a method of filling the conductive paste J4 (FIG. 6E) was performed.

However, as described above, in the method of laminating the green sheets under the interlayer wiring space J3 before filling the wiring space J3, the lamination, filling and printing are performed by the number of green sheets having the wiring space J3 in the layer. Since it has to be repeated, there has been a problem that the manufacturing process is complicated and disadvantageous in cost.

SUMMARY OF THE INVENTION In view of the above problems, the present invention relates to a ceramic laminated substrate having an in-layer wiring for lowering wiring resistance (hereinafter, this laminated substrate is referred to as an in-layer wiring holding substrate). It is an object of the present invention to provide a method for manufacturing a wiring board, in which the conductive paste is prevented from dripping after the space is filled with the conductive paste, and the manufacturing process is simplified.

[0010]

According to the present invention, in order to achieve the above object, there is provided a method for manufacturing an in-layer wiring holding board according to the present invention, wherein the in-layer wiring space (3) is provided. , One side (12a, 1) of the green sheet (12, 13)
3a) The first space chamber (4) opened to the side, and the other surface (12b, 13b) of the green sheet while closing the first space chamber at a portion communicating with the first space chamber. Forming an integrated one with a second space chamber (5) having an opening area smaller than that of the first space chamber; and forming the first space chamber in the in-layer wiring space (3). (4) a step of filling the conductive paste (7) from the side.

Thus, in the portion where the first and second space chambers (4, 5) communicate with each other, a part of the first space room is closed. Thus, when the conductive paste (7) is filled from the first space chamber side with the first space chamber facing upward, the closed part can receive the conductive paste. Further, since the second space has a smaller opening area than the first space, it is possible to prevent the conductive paste from dripping after filling with the conductive paste.

Therefore, when the wiring space in the layer is filled as in the prior art, the lamination, filling and printing are performed in the same manner as in the method of laminating the green sheet underneath. It is not necessary to repeat the process for each minute, and a desired wiring board can be obtained by stacking the layers at the end, so that the manufacturing process can be simplified.

The conductor paste (7) filled in the first space (4) becomes a conductor member (7a) after firing of the green sheets (11 to 14), and this conductor member (7a)
Thus, the wiring resistance can be reduced as in the conventional case. In the green sheets (12, 13), the conductive paste filled in the wiring space (3) in the layer is exposed on both surfaces of the green sheet, and is therefore arranged on the other green sheets (11 to 14). Electrical connection with the conductive paste can be made in the same manner as in the prior art.

According to a second aspect of the present invention, in the step of forming the in-layer wiring space (3), the green sheet (1) is formed.
2, 13) as the first green sheet (121, 1)
31) and a second green sheet (122, 132) are prepared, and a first through hole (4a) serving as a first space (4) is formed in the first green sheet. The second green sheet is formed with a second through hole (5a) serving as a second space chamber (5), and then the first and second through holes are communicated with each other so that the first and second through holes communicate with each other. It is characterized in that the in-layer wiring space is formed by bonding a second green sheet.

Thus, in addition to the same effect as the first aspect of the present invention, the first and second through holes (4a, 5a) having different shapes are formed in the first and second green sheets (121, 121), respectively. , 122, 131, and 132), and then the first and second green sheets are laminated to form the intra-layer wiring space (3), so that the intra-layer wiring can be easily formed. A space can be formed.

The reference numerals in the parentheses of the above means are examples showing the correspondence with specific means described in the embodiments described later.

[0017]

1 and 2 are process diagrams schematically showing a method for manufacturing a wiring board according to the present embodiment as sectional views, which show FIGS. 1 (a) to 1 (c), 2 (a) and 2 (a). (B)
This shows a state in the middle of finally forming the structure shown in FIG. FIGS. 3A and 3B are enlarged views of the in-layer wiring space 3 in FIG. 1B, wherein FIG. 3A is a top view and FIG.

An outline of this wiring board is shown in FIG.
As shown in (c), the wiring board of the present embodiment is formed by laminating a plurality of ceramic substrates 21, 22, 23, and 24, and inside each of the ceramic substrates 21 to 24, the through hole 2 and the in-layer wiring are provided. A wiring pattern is formed by the conductive member 7a filled in the space 3 and the conductive member 7a formed in a desired pattern on the surface of each of the ceramic substrates 21 to 24.

Next, a method of manufacturing the wiring board will be described.
First, green sheets 11 and 14 in which only through holes 2 are formed are prepared, and green sheets (first green sheets) 121 for upper layers are formed as green sheets 12 and 13 in which wiring spaces 3 in layers are formed. , 131
And the lower layer green sheet (second green sheet)
122 and 132 are prepared.

Here, the green sheets 11, 14,
In this example, alumina is used as the ceramic constituting 121, 122, 131, and 132. Further, as the upper green sheets 121 and 131, those having a thickness of about 0.1 to 0.5 mm, which is the same as that usually used, can be used.
2, 132 is relatively thinner than that,
Those having a thickness of about 0.25 mm are preferred.

Thereafter, as shown in FIG. 1A, the through holes 2 are formed in the green sheets 11 and 14 in which only the through holes 2 are formed. Also, the through holes 2 are provided for the upper green sheets 121 and 131.
And a first through hole 4a having an opening area larger than the through hole 2 is formed. Further, for the lower layer green sheets 122 and 132, the second through hole 5a having an opening area smaller than that of the first through hole 4a and having the same small opening diameter as the through hole 2, and the upper layer Of the green sheets 121 and 131 are formed. here,
The above-described through hole 2 and the first and second through holes 4
a, 5a are the respective green sheets 11, 14, 1
21, 122, 131, and 132 penetrate in the thickness direction, and can be formed by punching or the like.

Thereafter, as shown in FIG. 1 (b), the upper green sheets 121 and 131 and the lower green sheets 122 and 132 are laminated and integrated by pressurizing the first and second green sheets. The through holes 4a and 5a communicate with each other to form the in-layer wiring space 3. As a result, the first through hole 4a becomes the first space room 4, and the second through hole 5a becomes the second space room 5. Here, for example, as shown in FIG. 3, the first space chamber 4 is formed to have a rectangular shape with two sides of 2 mm and 50 mm at the opening, and the second space chamber 5 is formed with the opening. The portion can be formed in a shape such as a circle having a diameter of 0.2 mm.

As shown in FIG. 3, the in-layer wiring space 3 formed by laminating the two layers of the green sheets 121, 122, 131, and 132 forms one surface 12a of the green sheets 12, 13. , 13a side and other side 1
The shape (opening ratio) differs between the 2b and 13b sides, and in the in-layer wiring space 3, a part of the first space chamber 4 in a portion where the first and second space chambers 4 and 5 communicate with each other. Is formed. Then, as shown in FIGS. 1C and 2A, the through-hole 2 and the in-layer wiring space 3 are sequentially filled with the conductive paste 7 by a method such as screen printing, and the conductive paste 7 is dried. .

Here, the conductor paste 7 is placed in the wiring space 3 in the layer.
Is filled from the first space chamber 4 side forming the in-layer wiring space 3. That is, the green sheets 121 and 131 for the upper layer are filled. In addition, the wiring space 3 in the layer
Other surfaces 12b, 13 of the green sheets 12, 13 in
Since the b side is open, it can be filled under the same conditions as the through hole 2.
May be simultaneously filled with the conductive paste 7.

Subsequently, as shown in FIG. 2B, a pattern is printed on the surface of each of the green sheets 11 to 14 by screen printing or the like using the conductive paste 7, and the conductive paste 7 is dried. Here, it is preferable that the conductive paste 7 for forming a pattern is printed so as to have a thickness of about 20 μm after drying. Then, after laminating each of the green sheets 11 to 14, firing is performed at a temperature of about 1600 ° C. In the above-described series of steps, as the conductor paste 7 that becomes the conductor member 7a by firing, a paste containing W or Mo as a main component can be used. Then, through the above manufacturing steps, FIG.
As shown in (c), an in-layer wiring holding substrate having a closed surface 6 in the in-layer wiring space 3 is completed.

The completed wiring board is shown in FIG.
As shown in (c), a plurality of ceramic substrates 21 to 24
Is provided on at least one of the ceramic substrates 21 to 24 for reducing the wiring resistance and the wiring member 3 is filled with the conductor member 7a in the wiring space 3 in the layer formed so as to penetrate in the thickness direction. In the wiring board having the in-layer wiring portion, the ceramic substrates 22 and 23 in which the in-layer wiring space 3 is formed are formed by laminating first substrates 221 and 231 and second substrates 222 and 232. The wiring space 3 in the layer has a first space chamber 4 formed so as to penetrate the first substrates 221 and 231 in the thickness direction, and a second substrate 222.
232 is formed so as to penetrate in the thickness direction, and has an opening area integrated with a second space chamber 5 smaller than the first space chamber 4. At the boundary between the first space room 4 and the second space room 5, a part of the second substrates 222 and 232 closes the first space room 4.

By the way, according to the present embodiment, in the portion where the first and second space chambers 4 and 5 communicate with each other, a part of the first space chamber 4 is closed and a closed surface 6 is formed. Therefore, when the conductive paste 7 is filled into the in-layer wiring space 3 from the first space chamber 4 side, the closed surface 6 can receive the conductive paste 7. Further, since the second space 5 has a small opening area like the through hole 2, the conductive paste 7 filled in the second space 5 does not drip. Therefore, it is possible to prevent the conductive paste 7 from dripping after the conductive paste 7 is filled in the wiring space 3 within the layer.

Therefore, as in the prior art, when the wiring space in the layer is filled, the lamination, filling and printing are performed by the number of green sheets having the wiring space in the layer, as in the method of laminating the green sheet under the wiring space in advance. Since there is no need to repeat the steps, since a wiring board having a reduced wiring resistance can be obtained as in the related art by stacking the layers at the end, even if the in-layer wiring space 3 is formed on a plurality of green sheets. The manufacturing process can be simplified.

Further, the first and second through holes 4a and 5a having different shapes are formed with respect to the upper and lower green sheets 121, 122, 131 and 132, respectively.
It can be formed individually by punching or the like, and then two layers of green sheets 121, 122, 131, 1
The in-layer wiring space 3 can be formed by stacking the layers 32. Therefore, the wiring resistance can be reduced, and the in-layer wiring space 3 having the closed surface 6 that can receive the conductive paste 7 can be easily formed.

The first space chamber 4 has an opening area larger than that of the through-hole 2 in order to reduce the wiring resistance, similarly to the conventional wiring holding substrate in a layer. Therefore, the conductor paste 7 filled in the first space 4 becomes the conductor member 7a after firing the green sheets 11 to 14,
With the conductor member 7a, the wiring resistance can be reduced as in the conventional case. Green sheets 12 and 13
, The intra-layer wiring space 3 is
The conductor member 7a in the in-layer wiring space 3 is exposed on both surfaces of the green sheets 12 and 13, so that the conductor members 7a arranged on the other green sheets 11 to 14 Can be electrically connected as before.

The shape of the opening of the second space 5 is not limited to a circular shape as shown in FIG. 3, and the conductive paste 7 is printed when the conductive paste 7 is printed in the first space 4. If the shape has a small opening area that can prevent dripping,
Any shape may be used. 4 and 5 show a modification of the intra-layer wiring space 3. FIGS. 4 (a) and 5 (a) are top views, and FIGS. 4 (b) and 5 (b) are FIGS. 4 (a). FIG. 6 is a sectional view taken along line BB and CC in FIG. 5A.

In the example shown in FIG. 4, the second space 5 has one rectangular opening having an opening area smaller than that of the first space 4. In the example shown in FIG. The second space 5 has a plurality of rectangular openings each having an opening area smaller than that of the first space 4. For example, FIG.
As shown in (a), the opening of the first space chamber 4 can be a rectangle having two sides of 2 mm and 50 mm, and the opening of the second space chamber 5 has the sides of 0.4 mm and 49 mm. It can be rectangular. Further, as shown in FIG. 5A, the opening of the first space chamber 4 can be a rectangle having two sides of 2 mm and 50 mm, and each opening of the second space chamber 5 is It can be a rectangle having two sides of 0.2 mm and 0.4 mm. (Other Embodiments) In this embodiment, the conductive paste 7
The in-layer wiring space 3 which can prevent the sagging of the green sheet 121 is formed by integrating the two layers of green sheets 121, 122, 131 and 132.
13 may be formed of a single layer of green sheet, and the in-layer wiring space 3 having different shapes on one surface side and the other surface side may be formed in this one layer green sheet. Furthermore, when the green sheets 11 to 14 are stacked, the in-layer wiring space 3
May be in the uppermost layer or the lowermost layer, and the green sheet forming the in-layer wiring space 3 may be a single layer, May be formed in the green sheet of FIG.

The conductor paste 7 filling the through holes 2 and the conductor paste 7 filling the in-layer wiring space 3
Each component of the conductive paste 7 that forms a pattern on the surface of the green sheets 11 to 14 may be the same or different as long as it has W or Mo as a main component. In addition, the green sheet 12 for the lower layer
2 and 132 are the upper green sheets 121 and 13.
It does not necessarily need to be thinner than 1.

[Brief description of the drawings]

FIG. 1 is a process chart illustrating a method for manufacturing a wiring board according to an embodiment.

FIG. 2 is a process chart showing a manufacturing method following FIG. 1;

FIG. 3 is a partially enlarged view of an intra-layer wiring space of the present embodiment.

FIG. 4 is a diagram showing another example of the intra-layer wiring space of the present embodiment.

FIG. 5 is a view showing another example of the intra-layer wiring space of the embodiment;

FIG. 6 is a process chart showing a conventional method for manufacturing a wiring board.

FIG. 7 is a process drawing illustrating the method for manufacturing the wiring board following FIG. 6;

FIG. 8 is an explanatory diagram regarding filling of a conductive paste into an intra-layer wiring space.

[Explanation of symbols]

3 ... wiring space in a layer, 4 ... first space room, 4a ... first through hole, 5 ... second space room, 5a ... second through hole, 7 ... conductor paste, 11, 12, 13, 14 green sheet, 121, 131 first green sheet, 122,
132: Second green sheet.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Nagasaka 1-1-1, Showa-cho, Kariya-shi, Aichi F-term in Denso Corporation (reference) 5E317 AA24 BB04 BB11 CC17 CC25 CD32 GG11 5E346 AA12 AA15 AA43 BB01 BB15 CC17 CC31 DD13 DD34 EE24 EE29 FF18 GG04 GG06 GG08 HH02

Claims (2)

[Claims] A plurality of laminated green sheets (11)
To 14), an in-layer wiring space (3) penetrating in the thickness direction thereof is formed, and the in-layer wiring space (3) is filled with a conductive paste (7). A method of manufacturing a substrate, wherein a green sheet (1) is used as the in-layer wiring space (3).
2, 13), the first opening on one side (12a, 13a) side.
And a portion communicating with the first space chamber (4), while closing a part of the first space chamber (4), while closing the green sheet (12, 13). A step of forming an opening that is open to the surface (12b, 13b) side and has an opening area integrated with a second space chamber (5) smaller than the first space chamber (4); Filling the wiring space (3) with the conductive paste (7) from the first space chamber (4) side. 2. In the step of forming the intra-layer wiring space (3), as the green sheets (12, 13),
A first green sheet (121, 131) and a second green sheet (122, 132) are prepared, and the first green sheet (121, 131) becomes the first space chamber (4). First through holes (4a) are formed, and the second green sheets (122, 132) are
Forming a second through-hole (5a) to be the second space chamber (5), and then forming the first and second through-holes (4a, 5a) so as to communicate with each other. The method according to claim 1, wherein the in-layer wiring space (3) is formed by bonding second green sheets (121, 122, 131, 132).