JPH1074887A - Electronic part and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable mounting of a chip part on a solder ball formation side for improving its mounting density. SOLUTION: Chip parts 3, 6, 8 and 11 are mounted on opposing major surfaces 1a and 1b of a substrate 1 respectively, and spacers 12 and 13 which are higher in level than the mounted chip parts 8 and 11 are mounted also on the major surface 1b. The spacers 12 and 13 are arranged so that one major surfaces 12a and 13a of the spacers facing the substrate are conducted with major surfaces 12b and 13b thereof opposed thereto, solder balls 17 and 21 are placed on the spacers 12 and 13 to be connected with the chip parts 3, 6, 8, and 11 through the spacer 12 and 13, and function as terminals for interconnection with the external devices.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of mounting a bare chip on a substrate, forming a land electrically connected to the bare chip on a surface of the substrate opposite to the surface on which the bare chip is mounted, and mounting the land on the land. Arranged solder balls as terminals,
The present invention relates to a so-called ball grid array type electronic component. More specifically, the present invention relates to an electronic component in which a bare chip can be mounted on the solder ball forming surface side and the mounting density is improved.

[0002]

2. Description of the Related Art With the rapid development of surface mounting technology, high-density mounting of chip components has been promoted in electronic components in which various chip components such as IC packages are mounted on a printed wiring board. . Thus, although the miniaturization of IC packages and the like are being promoted, it is difficult to achieve higher-density mounting than at present. In contrast, in recent years, I
So-called bare chip mounting, in which a C chip is taken out of an IC package and mounted directly on a substrate, is being studied.

As a method for performing the above-described bare chip mounting, for example, a ball grid array system (hereinafter, referred to as a BGA system) can be cited. BGA above
In the method, in an IC chip that is a bare chip, a substrate on which printed wiring is performed is arranged on a printed wiring board facing surface side called a motherboard, and a terminal portion of the IC chip is connected to the printed wiring board facing surface side of this substrate. As well as
A ball grid array type electronic component (hereinafter, referred to as BGA) having a second land formed as a connection terminal with the outside and a solder ball mounted on the second land.
Is prepared, and the solder ball is melted and solidified, and B
The land of the GA is connected to the land of a printed wiring board called a motherboard, and a BGA is mounted on the printed wiring board. That is, in the BGA, the solder ball functions as a substantial connection terminal with the outside.

In the BGA substrate, a first land corresponding to a terminal portion of an IC chip is formed on one main surface and connected to the terminal portion, and the first land is formed on an opposing main surface. A second land connected to the land by a wiring circuit pattern is formed, and the terminal of the IC chip is connected to the second land by connecting the terminal of the IC chip to the first land.
Are connected to each other. That is,
In the BGA method, the terminal portion of the IC chip is drawn out to the outside via the substrate, and the position of the second land serving as a connection terminal with the outside can be relatively freely determined.

[0005] Specific examples of the shape of the BGA include the following. That is, as shown in FIG. 17, a chip component 102 which is a bare chip of an IC chip is mounted on one main surface 101a side of a substrate 101, and the other main surface 101b side opposite to one main surface 101a of the substrate 101. In which a solder ball 103 is formed. The chip component 102 is a wire 104
Main surface 1 of substrate 101 by wire bonding
01a is connected to a wiring circuit pattern (not shown) on the main surface 101 of the substrate 101.
It is connected to a land (not shown) formed on one main surface 101b opposite to a. Therefore, the chip component 10
2 and the land formed on one main surface 101b are electrically connected, and the solder ball 103 functions as a connection terminal with the outside.

FIG. 18 shows such a BGA as viewed from one main surface 101b side. Solder balls 103 are formed along the four sides of the substrate 101, for example, as shown in FIG. .

As shown in FIG. 17, a sealant 105 is provided for the chip component 102 in order to protect the chip component 102. FIG. As shown in FIG. 5, the sealant 105 is disposed so as to completely cover the chip component 102.

[0010] As shown in FIG. 20, such a BGA is formed by solder balls 103 on motherboard 10.
6 is mounted by soldering to a land in a wiring circuit pattern (not shown) on one main surface 106a.

[0009]

By the way, it is desired to further improve the mounting density of such electronic components as BGA. Therefore, the solder ball 103 on one main surface 101b side of the substrate 101 as shown in FIG.
It has been considered that a chip component is also mounted on a portion where no is formed. However, at present, the height of the solder ball 103 is extremely small, about 760 μm, and when a chip component is mounted on the solder ball 103 forming surface side,
In many cases, the height of the chip component is higher than the height of the solder ball 103, so that soldering to the mother board 106 by the solder ball 103 becomes impossible, and it is difficult to realize.

Further, in a multi-chip module on which various types of chip components are mounted, it is difficult to reduce the size by a normal mounting method, and mounting on both sides of a substrate is strongly desired as described above. I have.

In view of the above, the present invention has been proposed in view of the conventional situation, and an electronic component and a method of manufacturing the electronic component, which enable mounting of a chip component on a solder ball forming surface side and increase in mounting density. The purpose is to provide.

[0012]

In order to achieve the above object, an electronic component according to the present invention has chip components mounted on both sides of a substrate, and one of these main surfaces has a height higher than that of the chip component. A high spacer is also mounted, this spacer is assumed to be electrically connected between the substrate facing surface and the main surface facing the substrate, solder balls are arranged on the spacer, connected to chip components via the spacer, and external And a solder ball functioning as a connection terminal with the solder ball.

At this time, it is preferable that the spacer is a chip-shaped member having a flat rectangular shape, and it is sufficient to dispose the spacer only on a necessary portion on the substrate.

Further, a method of manufacturing an electronic component according to the present invention includes a step of mounting a chip component on one main surface of a substrate, a step of mounting a chip component on the other main surface of the substrate, On this main surface, the height is higher than the mounted chip component, and the conduction between the substrate facing surface and the main surface facing the substrate is conducted, and the solder ball is placed on the main surface facing the substrate facing surface. And a step of mounting a spacer on which is disposed.

During the manufacturing process, when the chip component and the spacer are mounted on the main surface of the substrate on which the chip component and the spacer are mounted by soldering, these heat treatments are performed simultaneously. Is preferred.

In the electronic component of the present invention, chip components are mounted on both sides of the substrate, and a spacer having a height higher than the chip components mounted on this surface is mounted on one of the main surfaces. Since the solder ball functioning as a connection terminal with the outside is arranged thereon, the chip component on the solder ball forming surface side does not hinder the soldering by the solder ball.

Further, if the spacer is a chip-shaped member having a flat rectangular shape, it is easy to form the spacer only on a necessary portion of the substrate.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

The electronic component of this embodiment is as shown in FIG. That is, a chip component 3 or a die bonding agent (not shown), which is fixed on one principal surface 1a side of the substrate 1 having a planar rectangular shape by solder 2 and which is electrically connected to a wiring circuit pattern (not shown) of the substrate 1. A chip component 6 such as an IC, which is secured by a wire 4 and secured by a wire 4 to a wiring circuit pattern (not shown) of the substrate 1 and sealed by a sealant 5, is mounted.

In the electronic component of this embodiment,
The substrate 1 is also fixed to the substantially central portion on the one main surface 1b side opposite to the one main surface 1a of the substrate 1 by the solder 7, and
Of the substrate 1 is secured by a die bonding agent (not shown) and electrically connected to a wiring circuit pattern (not shown) of the substrate 1. Then, a chip component 11 such as an IC sealed with a sealing agent 10 is mounted.

Further, in the electronic component of this embodiment, a flat rectangular spacer having a height higher than that of the chip component 8 sealed with the chip component 8 and the sealing agent 10 on the one main surface 1 b side of the substrate 1. The substrates 12 and 13 are arranged so as to surround four sides of the substrate 1 (however, only two sides are shown in FIG. 1).

The spacer 12 has a through hole 14
And lands 15 and 16 formed on one main surface 12a to be a substrate facing surface and main surface 12b opposed thereto, respectively.
The electrical connection between them is made possible. The solder balls 17 are arranged on the lands 16 on the main surface 12b opposed to the one main surface 12a serving as the substrate facing surface.

Similarly, one spacer 13 has a through hole 18 and has an electrical connection between lands 19 and 20 formed on one main surface 13a, which is a substrate facing surface, and a main surface 13b opposed thereto. Connection is possible.
The solder balls 21 are arranged on the lands 20 on the main surface 13b facing the one main surface 13a serving as the substrate facing surface.

Further, in the spacers 12 and 13, the lands 15 and 19 on one of the principal surfaces 12a and 13a, which are the substrate facing surfaces, are connected to a wiring circuit pattern (not shown) of the substrate 1 by solders 22 and 23.

In the substrate 1, the terminals derived from the chip components 3, 6, 8, 11 are connected to the lands 15, 1
9 is formed.

Therefore, the terminals derived from each of the chip components 3, 6, 8, and 11 are integrated in a wiring circuit pattern (not shown) on the one main surface 1b side of the substrate 1, and the spacers 12 and 13 through spacer 1
The solder balls 17 and 21 are formed on the surfaces of the solder balls 17 and 21 and function as external connection terminals.

That is, when the electronic component of this embodiment is viewed from the one main surface 1b side of the substrate 1, spacers are arranged along four sides of the substrate 1, and solder balls are formed in a shape as shown in FIG. It will be. Then, the chip components 8 and 11 are arranged at a substantially central portion of the substrate where no solder ball is formed.

FIG. 2 shows a state in which the electronic component of this embodiment is mounted on a motherboard. In the electronic component of the present embodiment, the solder balls 17, 21 are melted and solidified to be electrically connected and fixed to a wiring circuit pattern (not shown) on one main surface 24a of the motherboard 24, and mounted. At this time, in the electronic component of this example, the solder ball 1
7, 21 are disposed on spacers 12, 13 which are higher than the chip component 8 disposed on the one main surface 1b side and the chip component 11 sealed with the sealing agent 10,
Even if the chip components 8 and 11 are arranged on the one main surface 1b side, the soldering by the solder balls 17 and 21 is not hindered.

Therefore, chip components can be mounted on both sides of the substrate 1, and the mounting density can be improved.

Further, if the spacers 12 and 13 are formed as planar rectangular chip-shaped members as in the electronic component of the present embodiment, it is possible to form the spacers 12 and 13 only on necessary portions of the substrate 1. As shown in the example, the solder balls 17, 21 are formed along the four sides of the substrate 1,
The chip components 8 and 11 are arranged inside the
It is easy to change the shape.

Next, a method for manufacturing the electronic component of this embodiment will be described. First, a method for manufacturing a spacer will be described.
Here, the spacer 12 will be described as an example.
In other words, as shown in FIGS. 3A and 3B, one main surface 12a which is the substrate facing surface is shifted from one main surface 12a facing the substrate.
b, a through hole 14 in which a conductive film (not shown) is formed on the inner wall surface, and a conductive circular flat hole is formed at a position corresponding to the upper and lower openings of the through hole 14. Land 1 which is a pattern
Spacer 1 in which lands 15 on one main surface 12a and lands 16 on one main surface 12b are formed and conduction is established between them.
Prepare 2 In addition, in this spacer 12,
Resin 2 such as an ultraviolet curable resin is provided inside through hole 14.
5 are filled.

Next, as shown in FIG. 4, a flux (not shown) is applied to the entire surface of the main surface 12b opposite to the one main surface 12a which is the substrate facing surface, and the solder balls 17 are mounted on the lands 16. Thereafter, a heat treatment called reflow is performed to connect the solder balls 17 and the lands 16, and the remaining flux is washed to complete the spacer 12. Then, the spacer 13 is manufactured in the same manner.

Next, as shown in FIG. 5, a predetermined wiring circuit pattern (not shown) is formed on the opposing main surfaces 1a and 1b, and a substrate 1 to which these are connected as necessary is prepared. Next, a cream solder 26 is applied, for example, by screen printing, to the mounting position of the chip component to be mounted by soldering on one main surface 1a of the substrate 1 on the side where the solder balls are not formed.

Next, as shown in FIG. 6, the chip component 3 to be mounted by soldering is placed on the cream solder 26 applied to a predetermined position. Then, a heat treatment called reflow is performed to melt and solidify the cream solder 26, fix the chip component 3 with the solder 2 as shown in FIG. And electrical connection with the chip component 3
Implement

Next, as shown in FIG. 8, a chip component 6 such as an IC is placed on one main surface 1a side of the substrate 1 after applying a die bonding agent (not shown) thereto, and a heating called a cure is performed. The processing is performed, for example, under the condition of 125 ° C. × 1 hour, and the chip component 6 is bonded onto the substrate 1.

Subsequently, as shown in FIG.
Is bonded by wire 4 made of gold or aluminum or the like between the terminal and the wiring circuit pattern (not shown) on one main surface 1a of the substrate 1 to secure an electrical connection therebetween.

Further, the chip component 6 is covered with a sealing agent, which is a resin, and is subjected to a heat treatment called curing, and the chip component 6 is sealed with the sealing agent 5 as shown in FIG. .

Next, as shown in FIG. 11, the substrate 1 is turned upside down and, for example, a screen is placed at a mounting position of a chip component for mounting by soldering one main surface 1b opposite to one main surface 1a of the substrate 1. The cream solder 27 is applied by printing, and the cream solder 28 is also applied to the mounting position of the spacer.

Subsequently, as shown in FIG. 12, the chip component 8 is placed on the cream solder 27 applied to the mounting position of the chip component to be mounted on one main surface 1b of the substrate 1 by soldering. Then, a heat treatment called a reflow is performed to melt and solidify the cream solder 27, and FIG.
As shown in FIG. 7, the chip component 8 is fixed by the solder 7 and the chip component 8 is mounted while securing electrical connection with a wiring circuit pattern (not shown) on the one main surface 1b of the substrate 1.

Further, as shown in FIG. 13, a chip component 11 such as an IC is placed on one principal surface 1b side of the substrate 1 after applying a die bonding agent (not shown), and a heating called a cure is performed. The processing is performed under the conditions of, for example, 125 ° C. × 1 hour, and the chip component 11 is bonded to the substrate 1.

Subsequently, as shown in FIG. 14, the terminals of the chip component 11 and the wiring circuit patterns (not shown) on the one main surface 1b of the substrate 1 are wire-bonded by wires 9 made of gold or aluminum. To secure the electrical connection between

Further, the chip component 11 is covered with a sealant, which is a resin, and is subjected to a heat treatment called curing, so that the chip component 11 is covered with the sealant 1 as shown in FIG.
Seal with 0.

Finally, as shown in FIG. 16, the spacers 12, 13 manufactured by the above-described method are placed on the cream solder 28 disposed at the spacer mounting position on one main surface 1b of the substrate 1. The electronic component of this example as shown in FIG. 1 is completed by mounting and performing a heating process called reflow.

In the electronic component of this embodiment, the spacer 1
Since the chip members 2 and 13 are flat rectangular chip members, the spacers 12 and 1 are formed in the same manner as a normal chip component.
3 can be arranged on a substrate, and can be manufactured without significantly changing a conventional manufacturing process.

When the electronic component of this embodiment is manufactured, a heat treatment called reflow of the chip component 8 on one main surface 1b side of the substrate 1 and reflow of the spacers 12 and 13 may be performed simultaneously. It is preferable because the manufacturing process is shortened.

[0046]

As is apparent from the above description, in the electronic component of the present invention, chip components are mounted on both sides of the substrate, and one of the main surfaces is mounted on this surface. A spacer that is higher than the chip component is mounted, and solder balls that function as connection terminals with the outside are arranged on this.The chip component on the solder ball forming surface side does not prevent soldering with solder balls. Instead, the mounting density can be improved by using both sides of the substrate.

Further, if the spacer is a chip-shaped member having a flat rectangular shape, it becomes easy to form the spacer only on a necessary portion of the substrate, and it is possible to carry out the manufacturing without largely changing the manufacturing process. It is possible and its industrial value is very high.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a main part showing an electronic component to which the present invention is applied.

FIG. 2 is a main part schematic cross-sectional view showing a state where an electronic component to which the present invention is applied is mounted on a motherboard.

FIG. 3 shows a method of manufacturing an electronic component to which the present invention is applied in order of steps, and is a schematic plan view and a schematic cross-sectional view of a main part showing a step of manufacturing a spacer.

FIG. 4 is a schematic cross-sectional view of a main part showing a method of manufacturing an electronic component to which the present invention is applied, in the order of steps, showing a step of arranging solder balls on spacers.

FIG. 5 is a schematic cross-sectional view of a main part, showing a method of manufacturing an electronic component to which the present invention is applied in the order of steps and showing a step of applying cream solder on one main surface of a substrate.

FIG. 6 is a schematic cross-sectional view of a main part, showing a method of manufacturing an electronic component to which the present invention is applied in the order of steps, and showing a step of mounting a chip component on cream solder.

FIG. 7 is a schematic cross-sectional view of a main part showing a method of manufacturing an electronic component to which the present invention is applied, in the order of steps, showing a step of mounting a chip component.

FIG. 8 is a schematic cross-sectional view of a main part, showing a method of manufacturing an electronic component to which the present invention is applied in the order of steps, and showing a step of bonding a chip component onto a substrate.

FIG. 9 is a schematic cross-sectional view of a main part showing a method of manufacturing an electronic component to which the present invention is applied, in the order of steps, showing a step of wire-bonding a chip part.

FIG. 10 is a schematic cross-sectional view of a principal part showing a method of manufacturing an electronic component to which the present invention is applied, in the order of steps, showing a step of sealing a chip component with a sealing agent.

FIG. 11 is a schematic cross-sectional view of a main part, showing a method of manufacturing an electronic component to which the present invention is applied in the order of steps and showing a step of applying cream solder on the other main surface of the substrate.

FIG. 12 is a schematic cross-sectional view of a main part, showing a method of manufacturing an electronic component to which the present invention is applied in the order of steps, and showing a step of mounting a chip component on cream solder.

FIG. 13 is a schematic cross-sectional view of a main part showing a method of manufacturing an electronic component to which the present invention is applied in the order of steps, showing a step of mounting a chip part and a step of bonding the chip part onto a substrate.

FIG. 14 is a schematic cross-sectional view of a main part, showing a method of manufacturing an electronic component to which the present invention is applied in the order of steps, and showing a step of wire-bonding a chip component.

FIG. 15 is a schematic cross-sectional view of a main part, illustrating a method of manufacturing an electronic component to which the present invention is applied in the order of steps, and illustrating a step of sealing a chip component with a sealing agent.

FIG. 16 is a schematic cross-sectional view of a main part, showing a method of manufacturing an electronic component to which the present invention is applied in the order of steps, and showing a step of mounting a spacer.

FIG. 17 is a schematic cross-sectional view of a main part showing a structure of a conventional BGA.

FIG. 18 is a schematic bottom view showing the structure of a conventional BGA.

FIG. 19 is a schematic plan view of a main part showing a structure of a conventional BGA.

FIG. 20 is a schematic cross-sectional view of a main part showing a state where a conventional BGA is mounted on a motherboard.

[Description of Signs] 1 substrate, 1a, 1b one main surface, 3, 6, 8, 11 chip components, 12, 13 spacer, 14, 18 through hole, 17, 21 solder ball

Claims (4)

[Claims] 1. A chip component is mounted on both sides of a substrate, and a spacer having a height higher than that of the chip component is mounted on one main surface of the chip components. An electronic component, wherein the opposing main surfaces are electrically connected to each other, and solder balls, which are connection terminals with the outside of the chip component, are arranged via the spacer. 2. The electronic component according to claim 1, wherein the spacer is a chip-shaped member having a flat rectangular shape. A step of mounting a chip component on one main surface of the substrate; a step of mounting a chip component on the other main surface of the substrate; and a step of mounting the chip component on the main surface. And a step of mounting a spacer in which solder balls are arranged on the main surface opposite to the substrate facing surface, in which electrical conduction is provided between the substrate facing surface and the main surface facing the substrate. A method for manufacturing an electronic component, comprising: 4. When the chip component and the spacer are mounted on the main surface of the substrate on which the chip component and the spacer are mounted by soldering, these heat treatments are performed simultaneously. 3. The method for manufacturing an electronic component according to 3.