JP2000243869A - Wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board with a stiffener made of metal which does not obstruct mounting of an electronic component and can be miniaturized. SOLUTION: In a wiring board 1 where an electronic component 105 different from a semiconductor element 100 is mounted on a part position of an aperture 26 of a hole or a notch formed in a stiffener 21 made of metal, an insulating layer 31 is formed on a wall surface 26a of the aperture 26. Since the insulating layer 31 is formed on the wall surface 26a, possibility of shortcircutting is excluded, so that the aperture 26 can be miniaturized to the limit size capable of insertion of the electronic component 105. Thereby strength of the stiffener 21 can be increased as completely as possible, and the wiring board 1 can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wiring board (IC package) used for mounting (sealing) electronic components such as a semiconductor device (semiconductor integrated circuit device) such as an MPU.
More specifically, a metal stiffener is bonded to a substrate, and an electronic component (electronic element) different from the semiconductor element is mounted on an opening such as a hole or a notch formed in the metal stiffener. Related to a wiring board.

[0002]

2. Description of the Related Art A semiconductor element (hereinafter also referred to as an IC chip) is mounted on a wiring board to which a metal stiffener (reinforcement plate) is joined.
In addition to the above, there is the following structure for mounting another electronic component. For example, as in the case of the wiring board 111 shown in FIG. 5, the area of the rectangular opening (opening) 125 for mounting the IC chip of the metal stiffener 121 is enlarged as a whole, and the periphery (outside) of the mounted IC chip 100. Then, the electronic component 105 is mounted while maintaining the interval. Further, like the wiring board 112 shown in FIG. 6, an opening (hole) 126 dedicated to the electronic component 105 independent of the IC chip mounting opening 125 is provided in the metal stiffener 121, and a portion of the dedicated opening 126 is provided. The electronic component 105 is mounted on the device. Further, the wiring board 11 shown in FIG.
As shown in FIG. 3, a notch (recess) 126 is provided by locally opening and widening the mounting opening 125 of the IC chip 100, and the electronic component 105 is mounted in the notch 126.

In view of the role of the metal stiffener 121 constituting such a wiring board as a reinforcing material, it is preferable to make the opening where the electronic component is mounted as small as possible and to secure a large width of the remaining stiffener. However, the entirety of the opening (opening) 125 for mounting the IC chip as in the wiring board 111 shown in FIG.
In the case where the electronic component 105 is mounted around (outside) 00, the risk that the electronic component 105 comes into contact with the IC chip 100 during mounting increases as the opening 125 becomes smaller.

On the other hand, the wiring board 11 shown in FIGS.
In the case where the independent or notched openings 126 are provided as in 2, 113, there is no problem of contact with the IC chip 100. However, in these devices, it is necessary to reliably provide a gap between the wall surface and the electronic component 105 in order to ensure insulation from the wall surface of the opening 126 provided in the stiffener 121. For this reason, conventionally, the opening 1 is formed so that an appropriate gap is formed.
26 was formed larger. Further, as shown in FIG. 8, when the electronic component 105 is mounted,
A guide (jig) 108 is inserted along 6a, and the electronic component 105 is dropped and positioned along the guide 108. Then, the electronic component 105 is placed under the substrate 11.
Solder was applied to the terminal formed on the surface 0 to prevent molten solder from spreading on the gold-plated surface applied to the wall surface 126a of the opening 126 of the stiffener 121, for example, a copper alloy stiffener.

[0005]

As described above, in the wiring board 111 shown in FIG. 5, it is necessary to reduce the size of the opening 125 in order to increase the strength of the stiffener 121.
The risk of contact with the IC chip 100 in mounting the electronic component 105 increases. On the other hand, the opening 125 is enlarged,
In addition, in order not to reduce the strength, it is necessary to increase the planar shape of the stiffener 121 and the wiring substrate 111, and it is not possible to meet the demand for miniaturization of the semiconductor device. Such a problem becomes more remarkable as the number of electronic components to be mounted increases. For this reason, in some cases, only the electronic components may be separated from the IC chip and installed on the motherboard. However, this is not preferable in terms of electrical characteristics, such as increasing the wiring distance to the IC chip and causing signal delay.

Further, in the case of the structure shown in FIGS. 6 and 7, as shown in FIG.
Since the guide 108 is inserted along the wall surface of the opening 126 and is positioned and mounted by being set in a recessed shape while being guided by this, the work efficiency is poor, such as the need for such a guide 108. An object of the present invention is to provide a wiring board with a metal stiffener that can achieve downsizing without hindering mounting of electronic components.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a method of manufacturing a semiconductor device, comprising the steps of: joining a metal stiffener to a substrate; and forming a semiconductor device in a hole or a notch formed in the metal stiffener. In a wiring board for mounting a semiconductor element on which an electronic component different from the element is mounted, an insulating layer is formed on a wall surface of the opening.

In the above means, since the insulating layer is formed on the wall surface of the opening, there is no problem of short-circuiting. Therefore, the opening formed in the metal stiffener is as small as possible to insert electronic components. can do. That is, according to the present invention, there is no danger of a short circuit in the mounting of the electronic component. Therefore, the strength of the stiffener can be increased as much as possible, and the size of the stiffener and the wiring board can be reduced.

Furthermore, if the opening is formed to the size just enough to allow the insertion of an electronic component, the wall surface of the opening can be used as a guide at the time of insertion, so that a mounting guide (jig) as in the prior art is used. By simply dropping electronic components without the need for mounting, positioning and mounting of terminals can be performed without fear of short-circuiting. Therefore, the efficiency of the mounting work of the electronic components can be improved, and a significant improvement in the working efficiency is expected.

In the above means, the insulating layer may be formed of an appropriate material (insulating material) such as resin or ceramic. Incidentally, the material for forming the stiffener is preferably formed of copper or a copper alloy in view of strength and heat transfer coefficient.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to FIGS. FIG. 1 is a sectional view showing a wiring board 1 of the present embodiment, FIG. 2 is an enlarged view of a main part A thereof, and FIG. 3 is a plan view of FIG. This wiring substrate 1 is mainly composed of a laminated organic substrate 2 and a copper stiffener 21 and has an LG
A (land grid array) type is configured as follows. That is, the substrate 2 is provided with a predetermined wiring layer (not shown) and is formed in a substantially rectangular plate shape in plan view. The upper surface 3 is connected to electrodes of IC chips and electronic components to be mounted. Terminal 5 and die attach part 6
Are formed. A large number of terminals 7 are arranged on the illustrated lower surface 4 of the substrate 2, and these terminals and the like are plated with Ni and gold.

A stiffener 21 made of copper in this embodiment is bonded to the upper surface 3 of the substrate 2 by thermosetting adhesive (resin).
For example, it is pressed and bonded at 175 ° C. for 2 hours via the sheet 9. This stiffener 21 has an IC chip 10
In addition to the opening 25 that forms the mounting part of the electronic component 105, a plurality of openings 26 that form the mounting part of the electronic component 105 are provided. The opening 25 for mounting the IC chip at the center is rectangular in a plan view, and the plurality of openings 26 forming the mounting portion of the electronic component 105 are formed.
Is opened like a window on the outside. In this embodiment, a stiffener 21 is formed with a nickel plating layer and a gold plating layer on the outermost surface (not shown). Then, the wall surfaces 25a of the openings 25, 26 of the stiffener 21 and 2
An insulating layer 31 having a thickness of, for example, 10 to 30 μm is formed on 6a to form a mounting portion of an electronic component.

For example, after the formation of the stiffener 21 and before the adhesion to the substrate 2, the insulating layer 31 is formed on the wall surfaces 25 a, 2
A thermosetting epoxy resin layer (paste) is screen-printed on 6a and thermoset at 150 ° C. for about 2 hours. The stiffener 21 is formed by forming openings 25 and 26 by machining such as cutting or punching by pressing, laser machining, electric discharge machining or the like, and then plating.

In the wiring board 1 with the stiffener of the present embodiment, the IC chips 10 are provided in the openings 25 and 26 thereof.
0 and other electronic components 105 are mounted by soldering, but there is no short-circuit problem in the mounting because the insulating layer 31 is formed on the wall surface 26a of the opening 26. Therefore, the opening 26 formed in the metal stiffener 21 can be reduced to a size as small as the size at which the electronic component 105 can be inserted. According to the present embodiment, there is no danger of a short circuit in mounting the electronic component 105, and the strength of the stiffener 21 can be increased as much as possible.
1 and the size of the wiring board 1 can be reduced.

In addition, as described above, the opening 26 is formed in the electronic component 10.
5, the wall 26a can be used as a guide at the time of insertion, so that only the electronic component 105 is dropped without a separate mounting guide (jig) as in the related art. In addition, the terminals can be positioned without fear of a short circuit. Therefore, the efficiency of the mounting work of the electronic component 105 can be improved, and a significant improvement in the working efficiency is expected. In order to perform such a guide function, it is preferable that the gap between the electronic component 105 and the wall surface 26a is, for example, 0.5 mm or less.
The size of the opening 26 may be set to be 0.5 mm.

In the present invention, the insulating layer may be formed only on the wall surface of the opening of the stiffener.
24 may be formed as a whole. However, in that case, both main surfaces 23 and 24 of the stiffener 21 and the wall surface 2
The intersection ridges formed with 5a and 26a may be chamfered in a round or inclined shape. Burrs are likely to be formed on the intersection ridges due to the manufacture of the stiffener 21. In such a case, the insulating layer 31 is hard to be maintained at a constant thickness at the burrs, but is maintained at a constant thickness if chamfered. Because it is easy to be done. However, even when the insulating layer is provided only on the wall surface of the opening, it is preferable that the intersection ridge formed between the wall surface and the main surface be chamfered in a round or inclined shape. In the case where the insulating layer is formed by printing a resin paste as in the above-described embodiment, if there is no chamfer at the intersection ridge, the excessively printed (coated) paste hangs down the wall surface as it is. It hardens and becomes burrs. However, if the chamfer is provided, even if the paste hangs down, the paste flows along the chamfered portion, so that the paste hardly forms burrs.

In the above embodiment, the insulating layer 31 is made of a thermosetting resin and is formed by a screen printing method. However, the forming method is not limited to this, and a resin sheet may be bonded. Further, it can be formed by spraying, sputtering, CVD or PVD of an insulating material such as ceramic. Note that the insulating layer can be formed after the stiffener is bonded to the substrate.

The present invention is not limited to the above-described embodiment, but can be embodied with various design changes. FIG. 4 shows another embodiment of the present invention. In the wiring board 51, the opening 26 for mounting the electronic component 105 is not an independent hole (opening) but a cutout continuous with the mounting opening 25 for the central IC chip 100, and an insulating layer ( (Not shown), but since there is no essential difference from the above-described embodiment, the same portions will be denoted by the same reference numerals and description thereof will be omitted. In any case, the number and arrangement of the openings 26 may be appropriately set according to the design.

In the above embodiment, the present invention is embodied in an LGA (land grid array) type wiring board.
Printed circuit board (external circuit board) such as (ball grid array) type and PGA (pin grid array) type
Regardless of the connection method, the present invention can be widely applied to various wiring boards in which a stiffener is joined and an electronic component is mounted on an opening formed in the stiffener. The stiffener may be made of not only copper and copper alloy but also stainless steel.

[0020]

As is clear from the above description, according to the wiring board with the stiffener of the present invention, since the insulating layer is formed on the wall surface of the opening, there is no short circuit problem. Therefore, the opening formed in the metal stiffener can be reduced to a size as small as possible to insert an electronic component.
That is, according to the present invention, there is no danger of a short circuit in the mounting of the electronic component, so that the strength of the stiffener can be increased as much as possible and the size of the wiring board can be reduced.

Furthermore, if the opening has a size just enough to allow the insertion of an electronic component, the wall surface of the opening can be used as a guide at the time of insertion, so that a mounting guide (jig) as in the prior art is used. By simply dropping electronic components without the need for mounting, positioning and mounting of terminals can be performed without fear of short-circuiting. Therefore, the efficiency of the mounting operation of the electronic component can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of a wiring board according to the present invention.

FIG. 2 is an enlarged view of a main part A of FIG.

FIG. 3 is a plan view of the wiring board of FIG. 1;

FIG. 4 is a plan view of another embodiment of the wiring board according to the present invention.

FIG. 5 is a plan view of a conventional wiring board with a metal stiffener.

FIG. 6 is a plan view of a conventional wiring board with a metal stiffener.

FIG. 7 is a plan view of a conventional wiring board with a metal stiffener.

FIG. 8 is an exemplary sectional view for mounting an electronic component in an opening of the wiring board in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wiring board 2 Substrate 21 Metal stiffener 26 Opening 26a Opening wall surface 31 Insulating layer 100 Semiconductor element 105 Electronic component

Claims (2)

[Claims] A metal stiffener is bonded to a substrate, and an electronic component different from the semiconductor element is mounted on an opening such as a hole or a notch formed in the metal stiffener. A wiring board, wherein an insulating layer is formed on a wall surface of the opening. 2. The wiring board according to claim 1, wherein the insulating layer is made of a resin.