JPH06103795B2 - Structure of multilayer wiring board - Google Patents

Description

Detailed Description of the Invention 【Overview】

Regarding a structure of a multilayer wiring board used for a high-speed electronic device such as a computer, an object thereof is to provide a structure of a multilayer wiring board which has a good yield at the time of manufacturing the board and can meet the demand for high speed. For pin insertion, which has at least one signal wiring layer above the main board on which the electronic component is mounted and in the gap between the electronic component and the back surface of the package, and through which the I / O pin of the electronic component is inserted Film wiring boards provided with through holes are stacked and arranged, and the film wiring boards and the electronic parts are joined by solder supplied to the pin insertion through holes.

[Industrial applications]

The present invention relates to a structure of a multilayer wiring board used in a high speed electronic device such as a computer. Generally, a high-speed electronic device such as a computer requires a high-density wiring board that accommodates fine wiring to satisfy the demand for high-speed operation, and a multilayer ceramic substrate that is effective for high-density operation is often used. Such multilayer ceramic substrates include a thick film substrate in which a pattern is formed on the inner layer of the ceramic by a thick film process, and a thin film substrate in which fine wiring is formed on the thick film substrate by processes such as spin coating, sputtering, and etching. From the viewpoints of high speed and high density, a thin film substrate that can use a low dielectric constant material such as polyimide as an insulator and is capable of forming a fine pattern is excellent.

[Prior art]

FIG. 14 shows a conventional multilayer wiring board. The multilayer wiring board shown is a thin film multilayer ceramic board. In the figure, 15 is a thick film ceramic board.
It is formed by firing a plurality of laminated green sheets while taking interlayer connection via 16. An insulating layer made of an insulating material such as polyimide is formed on the thick film ceramic substrate 15.
The ground layer 14 and the signal wiring layer 4 which is interlayer-connected by the via 16 are alternately formed through the via 17.

[Problems to be Solved by the Invention]

However, in the multilayer wiring board, the thin film process at the time of manufacturing the ceramic substrate is a serial process in which the spin coating of the insulating layer 17, the formation of the vias 16, the metal sputtering, and the etching are repeated, so that the yield decreases as the number of layers increases. In addition, when polyimide is used as the material of the insulating layer 17, the stress remaining after curing increases with an increase in the number of layers, which causes a problem such as film peeling. Furthermore, it has been pointed out that there is a limit to the reduction in the dielectric constant of the insulating layer 17 required for speeding up. The present invention has been made to solve the above drawbacks, and an object of the present invention is to provide a structure of a multilayer wiring board which has a good yield at the time of manufacturing a board and can meet the demand for higher speed.

[Means for Solving the Problems]

According to the present invention, the above-mentioned object is, as shown in FIGS. 1 to 4 corresponding to the embodiment, above the main substrate 2 on which the electronic component 1 is mounted and on the back surface of the package 3 of the electronic component 1. A film wiring board 7 having at least one signal wiring layer 4 and having a pin insertion through hole 6 through which the I / O pin 5 of the electronic component 1 is inserted is laminated and arranged in the gap. The film wiring board 7
This is achieved by providing a structure of a multilayer wiring board characterized in that the electronic component 1 and the electronic component 1 are joined by the solder 8 supplied to the pin insertion through hole 6. Further, the above-mentioned purpose is, as shown in FIGS. 10 and 11, that at least one signal wiring layer is provided with the I / O pin 11 provided on the back surface of the board connecting package 10 having the element bonding pad 9 formed on the front surface. 4 is inserted into the through hole 6 for pin insertion provided in the film wiring board 7 having 4 and soldered to mount the film wiring board 7 on the board connecting package 10.
This is also achieved by the structure of a multilayer wiring board in which the I / O pins 11 of the board connecting package 10 are bonded to the element bonding pads 12 of the main board 2.

[Action]

Based on the above configuration, the thin film wiring portion in the present invention can be spread on the film wiring board 7. As a result, the decrease in yield due to the thin film process is resolved,
And between the film wiring boards 7, as shown in FIG.
Since the air insulating layer 18 having a low dielectric constant is formed, it becomes possible to meet the demand for high-speed signals.

【Example】

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 to 4 show an embodiment of the present invention, in which 2 is a ceramic substrate (main substrate) in which a plurality of power source layers and signal layers are laminated by a thick film process, 23, 23 ... These are I / O pins that are erected in a matrix on the back surface of this ceramic substrate. Reference numeral 7 denotes a film wiring board mounted above the ceramic board 2. As shown in FIG. 2 (a), a double-sided board type in which signal wiring patterns 19 are arranged on the front and back surfaces of a polyimide insulator, Alternatively, as shown in FIG. 2 (b),
It is possible to use a multi-layer board type in which a ground layer 14 for impedance matching is formed in the central layer via a polyimide insulating layer 17 and signal wiring patterns 19 are arranged on the front and back surfaces. Wiring channel transfer vias 16 are provided at appropriate places on the film wiring board 7 to establish interlayer connection. Furthermore, the film wiring board 7 includes
A pin insertion through hole 6 that matches the I / O pin 5 of the semiconductor element to be mounted is formed, and by inserting the I / O pin 5 of the semiconductor element into this pin insertion through hole 6, a semiconductor element, etc. It can be mounted in the gap between the electronic component 1 and the ceramic substrate 2. FIG. 4 shows a mounting state of the film wiring board 7 formed as described above. In the figure, three film wiring boards 7 each having a ground layer 14 in the central portion are laminated to form a signal of 6 layers. Although the case where the wiring layers 4, 4 ... Are formed is shown, in addition to this, for example, as shown in FIG. 5, the film wiring board 7'for exclusive use of the ground and the film wiring board 7 for exclusive use of the wiring are alternately arranged. It is possible to take various configurations such as stacking on. In this case, in order to align the signal wirings and to prevent the short circuit between the film wiring boards 7, as shown in FIG. As shown in FIG. 2B, the plating 21 is laminated on the pin insertion through hole 6 of the film wiring board 7. Next, a method of mounting the multilayer wiring board according to this embodiment will be described. First, as shown in FIG. 7A, each film wiring board 7
Are stacked by using the I / O pins 5 of the semiconductor element 1 as a guide, and then are collectively soldered (see FIG. 7B). In this case, the solder 8 is supplied by inserting the solder ring 22 into the I / O pin 5 or by supplying the film wiring board 7 as shown in FIG.
This is done by applying solder plating to the through holes 6 for pin insertion. After the film substrate is bonded to the semiconductor element 1 as described above, the I / O pins 5 of the semiconductor element 1 are connected to the ceramic substrate 2
The film wiring board 7 and the semiconductor element 1 are simultaneously mounted by collectively soldering to the element bonding pad 12 (see FIG. 4 and FIG. 7C). When joining the film wiring board 7 to the semiconductor element 1, as shown in FIG. 9, the film wiring board 7 is first laminated using the reference pins 24 as guides, and then the I /
It is also possible to insert the O pins 5 into the pin insertion through holes 6 of the film wiring board 7 (see FIG. 9B) and perform soldering at once. 10 to 12 show another embodiment of the present invention. In this embodiment, the same components are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, each film wiring board 7, 7 ...
It is joined via the board connecting package 10, and the film wiring board 7 is provided on the back surface of the board connecting package 10.
I / O pins 11 and 11 corresponding to the through hole 6 for pin insertion
... are erected in a matrix. Further, the I / O pin bonding pad 25 formed on the back surface of the board connecting package 10 is led out to the via pad 27 on the front surface via the via 16 and the inner layer wiring pattern 26, and the via pad
It is expanded from 27 to the element bonding pad 9 corresponding to the I / O pin 5 of the semiconductor element 1 and the EC pad 13. Therefore, according to this embodiment, first, as shown in FIG. 13 (a), a plurality of film wiring boards 7, 7 ... Are stacked using the reference pin 24 as a guide, and then as shown in FIG. 13 (b). Then, the I / O pin 11 of the board connecting package 10 is inserted into the through hole 6 for pin insertion, and soldering is performed collectively. After that, the I / O pins 5 of the semiconductor element 1 are soldered onto the element bonding pads 9 of the board connecting package 10 to complete the mounting. However, in this embodiment having the EC pad 13, the board is modified. The via pad 27 as shown in FIG.
The lead-out pattern 28 that connects the device pad 9 and the element bonding pad 9 is cut off and cut off from the inner layer wiring, and the EC pads 13 are wired together.
Correspondence is taken by connecting at 29. Further, the mounting of the electronic component 1 in this embodiment is performed by bonding the leads of the electronic component 1 onto the element bonding pads 9 formed on the package 10 for connecting to the substrate, so that the I / O pin type external Not only those having connection terminals, but also electronic components having bump-type external connection terminals can be mounted, for example, as shown at the left end in FIG.

【The invention's effect】

As is clear from the above description, according to the structure of the multilayer wiring board of the present invention, it is possible to improve the yield at the time of manufacturing the board and to meet the demand for higher speed. In addition, when mounted via a board connecting package, replacement of semiconductor elements or the like, or board modification using discretes becomes easy.

[Brief description of drawings]

1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a film wiring substrate, FIG. 3 is a diagram showing a pattern of the film wiring substrate, FIG. 4 is an enlarged view of part A of FIG. 1, FIG. 5 is a view showing a modified example of FIG. 4, FIG. 6 is a view showing a laminated state of film wiring boards, FIG. 7 is a view showing a mounting process of the present invention, and FIG. 8 is soldering by a solder ring. FIG. 9 is a diagram showing a process, FIG. 9 is a diagram showing a modified example of the mounting process, FIG. 10 is a diagram showing another embodiment of the present invention, FIG. 11 is an enlarged view of part B of FIG. 10, and FIG. FIG. 13 is a diagram showing a surface pattern of a board connecting package, FIG. 13 is a diagram showing a mounting process, and FIG. 14 is a diagram showing a conventional example. In the figure, 1 ... Electronic parts, 2 ... Main board, 3 ... Package, 4 ... Signal wiring layer, 5 ... I / O pin, 6 ... Through hole for pin insertion, 7,7 '... Film wiring board, 8 ... Solder, 9 ... Element bonding pad, 10 ... Board connecting package, 11 ... I / O pin, 12 ... Element bonding pad, 13 ... EC pad, 14 ... Ground layer .

Claims (4)

[Claims] 1. At least one signal wiring layer (4) above a main board (2) on which an electronic component (1) is mounted and in a gap between the electronic component (1) and a back surface of a package (3). And a film wiring board (7) having a pin insertion through hole (6) through which the I / O pin (5) of the electronic component (1) is inserted, and the film wiring board is arranged. A structure of a multilayer wiring board, characterized in that the board (7) and the electronic component (1) are joined by solder (8) supplied to the through hole (6) for pin insertion. 2. An I / O pin (1) provided on the back surface of a package for board connection (10) having an element bonding pad (9) formed on the front surface.
1) is inserted into a pin insertion through hole (6) provided in a film wiring board (7) having at least one signal wiring layer (4) and soldered to the board connection package (10) to form a film wiring. While mounting the board (7),
A structure of a multilayer wiring board formed by bonding the I / O pins (11) of the board connecting package (10) to the element bonding pads (12) of the main board (2). 3. The structure of a multilayer wiring board according to claim 2, wherein an EC pad (13) is formed on the board connecting package (10). 4. The structure of the multilayer wiring board according to claim 1, 2 or 3, wherein the film wiring board (7) is a multilayer board having a ground layer (14) formed in a central portion thereof.