JPH11233670A - Circuit substrate structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit substrate structure on which a BGA package is surely mounted without junction failures in solder junctions. SOLUTION: This circuit substrate structure includes a circuit substrate, having a predetermined circuit pattern formed thereon and a BGA package 54 connected electrically to the circuit pattern of the circuit substrate. The BGA package 54 includes a chip carrier substrate 56, a chip 58 mounted on the chip carrier substrate 56, and solder balls connected electrically to the chip 58. The circuit substrate 52 and/or the chip carrier substrate 56 are provided thereon with resist layers 66 and 76. The resist layers 66 and 76 are formed therein with recesses 70 and 78 for accommodating parts of the solder balls therein.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a BGA
The present invention relates to a circuit board structure on which a package is mounted.

[0002]

2. Description of the Related Art Conventionally, as electronic devices have become smaller and thinner, LSI packages (or IC packages) having various structures and shapes have been developed and put to practical use. In particular, in recent years, as the circuit density has increased, a BGA package (a package in which a ball grid array is provided on the lower surface of a semiconductor package) that can provide many input / output terminals without increasing the size of the package itself is used. Is being done.

[0003] Such a BGA package has, for example, a configuration shown in FIG. Generally, the BGA package 4 includes a chip carrier substrate 6 and a chip 8 mounted on the upper surface of the chip carrier substrate 6, and the chip 8 is connected to the chip carrier substrate 6 via a plurality of bonding wires 10. It is electrically connected to the terminal. The chip 8 and the bonding wires 10 are hardened and sealed with a mold resin 12. A plurality of solder balls 14 as input / output terminals are provided in an array on the lower surface of the chip carrier substrate 6, and the solder balls 14 are attached to the chip 8 via the terminal portions of the chip carrier substrate 6 and the bonding wires 10. It is electrically connected. Such a BGA package 4 is mounted on the circuit board 2.
When mounted on the circuit board 2, the plurality of solder balls 14 of the BGA package 4 are respectively positioned on the corresponding solder pads 16 provided on the upper surface of the circuit board 2, and in this state, for example, hot air is blown. .
When the hot air is blown in this way, the terminal portions of the chip carrier substrate 6 and the solder pads 16 of the circuit board 2 are electrically joined via the molten solder.

[0004]

However, in the conventional BGA package 4, the chip carrier substrate 6
Since the solder balls 14 are merely provided at the terminal portions of the solder balls 14, when the hot air is blown to melt the solder balls 14, as shown in FIG. And the adjacent terminal portions of the chip carrier substrate 6 are electrically short-circuited (a state indicated by an arrow 20 in FIG. 5), or the solder balls 14 are electrically connected to the solder pads 16 of the circuit board 2. It may be in a so-called open state without being connected (the state shown by an arrow 20 in FIG. 5). When such a connection failure occurs, the chip 8 of the BGA package 4 does not function properly, and an operation failure of an electronic device using the circuit board structure occurs.

An object of the present invention is to provide a circuit board structure capable of preventing the occurrence of electrical connection failure and reliably mounting a BGA package on a circuit board.

[0006]

The present invention comprises a circuit board on which a predetermined circuit pattern is provided, and a BGA package electrically connected to the circuit pattern on the circuit board, wherein the BGA package is a chip. A carrier substrate,
In a circuit board structure having a chip mounted on the chip carrier board and solder balls electrically connected to the chip, an electrical insulating member is provided on a surface of the circuit board and / or the chip carrier board. A circuit board structure, wherein the insulating member is provided with a concave portion for accommodating a part of the solder ball corresponding to the solder ball.

According to the present invention, an electrical insulating member is provided on the surface of the circuit board and / or the chip carrier substrate, and the insulating member is provided with a ball for accommodating a part of the solder ball. Have been. Therefore, when the BGA package is mounted on the circuit board and the solder balls are melted, the solder joints between the BGA package solder balls and the circuit board are isolated from each other by the insulating member,
Short circuit between adjacent solder joints is prevented. In addition, since the solder balls can be formed relatively large, the solder balls and the circuit board are prevented from being electrically connected and opened.

Further, according to the present invention, the insulating member comprises a resist layer provided on a surface of the circuit board and / or the chip carrier substrate, and the resist layer has the concave portion corresponding to the solder ball. It is characterized by having.

According to the present invention, the insulating member is formed of a resist layer, and the resist layer is provided with a concave portion corresponding to the solder ball, so that the solder joint between the solder ball of the BGA package and the circuit board is formed by the resist. Each layer is insulated and isolated. Such a resist layer,
A resist layer formed on the surface of a circuit board and / or a chip carrier substrate can be used.

Further, according to the present invention, the insulating member is constituted by a spacer interposed between the circuit board and the chip carrier board, and a through hole is formed in the spacer corresponding to the solder ball. It is characterized by.

According to the present invention, the insulating member comprises a spacer interposed between the circuit board and the chip carrier substrate, and the spacer has a through hole corresponding to the solder ball. Therefore, when mounting the BGA package on the circuit board, a spacer may be interposed between them.
By thus interposing the spacer, the solder joint between the solder ball and the circuit board can be insulated and isolated from each other by the spacer.

Further, according to the present invention, the insulating member is formed of an insulating layer printed or applied on a surface of the circuit board and / or the chip carrier substrate, and the concave portion corresponding to the solder ball is formed in the insulating layer. It is characterized by being provided.

According to the present invention, the insulating member is formed from a printed or applied insulating layer, and the insulating layer has a recess corresponding to the solder ball. Therefore, before mounting the BGA package, the insulating layer may be formed by printing or coating. For example, the insulating layer can be easily formed on a manufacturing assembly line, and thus, the solder joint between the solder ball and the circuit board can be formed. The parts can be respectively insulated and isolated by an insulating layer.

Further, the present invention includes a base circuit board provided with a predetermined circuit pattern, an intermediate circuit board electrically connected to the circuit pattern of the base circuit board, and a BGA package. A chip carrier substrate, a chip mounted on the chip carrier substrate, and a solder ball electrically connected to the chip, wherein the intermediate circuit substrate is between the base circuit substrate and the chip carrier substrate. A circuit board structure, wherein a through hole is formed in the intermediate circuit board so as to correspond to the solder ball.

According to the present invention, the intermediate circuit board is interposed between the base circuit board and the chip carrier board, and the intermediate circuit board is formed with through holes corresponding to the solder balls. Therefore, B is connected to the circuit board via the intermediate circuit board.
By mounting the GA package, the solder joint between the solder ball and the circuit board can be insulated and isolated from each other by the intermediate circuit board. In addition, by interposing the intermediate circuit board in this way, a part of the circuit pattern of the circuit board can be formed on the intermediate circuit board, whereby the entire circuit board structure can be downsized.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a sectional view showing a first embodiment of a circuit board structure according to the present invention in a state where a circuit board and a BGA package are not electrically connected.

Referring to FIG. 1, a circuit board structure according to the present embodiment includes a circuit board 52 provided with a predetermined circuit pattern (not shown), and a BGA package 54 electrically connected to the circuit board 52. And The BGA package 54 includes a substantially rectangular chip carrier substrate 56, and a substantially rectangular chip 58 mounted on the upper surface of the chip carrier substrate 56 (the surface opposite to the surface electrically connected to the circuit substrate 52). It is composed of A chip 58 composed of an LSI, an IC, or the like is electrically connected to a pattern (not shown) of a chip carrier substrate 56 through a plurality of (four in FIG. 1) bonding wires 60,
Most of the upper surface of the chip 58 and the upper surface of the chip carrier substrate 56 are covered and sealed by the mold resin 62.

On the lower surface of the chip carrier substrate 56 (the surface connected to the circuit substrate 52), a resist layer 66 is provided as an electrically insulating insulating member. This resist layer 66 is formed by applying a resin on the surface of the chip carrier substrate 56 as required.
This resist layer 66 covers the lower surface of the chip carrier substrate 66 to ensure insulation.

A plurality of terminal portions 72 are provided on the lower surface of the chip carrier substrate 56 at intervals in the vertical direction (the direction perpendicular to the paper surface in FIG. 1) and the horizontal direction (the horizontal direction in FIG. 1). Each terminal 72 is electrically connected to a pattern (not shown) of the chip carrier substrate 56 as required. A circular concave portion 70 is provided on the surface of the resist layer 66 corresponding to each of the terminal portions 72, and the tip end surface of each terminal portion 72 is exposed on the bottom surface of the concave portion 70 as shown in FIG. ing.

In this embodiment, a part of the solder ball 68 is accommodated in each concave portion 70 of the resist layer 66, and each solder ball 68 is provided at the tip of the corresponding terminal 72.
The tip of each solder ball 68 protrudes outward from the recess 70. These solder balls 68 are connected to terminal portions 72.
Are electrically connected to a pattern (not shown) of the chip carrier substrate 56 via the.

The circuit board 52 includes a board body 73, and a circuit pattern (not shown) is formed on the surface of the board body 73, and the surface of the circuit pattern (the surface connected to the BGA package 54) A resist layer 76 is provided as an electrically insulating member. This resist layer 7
6 keeps the surface of the circuit board 52 insulative. In the resist layer 76, a plurality of concave portions 78 are respectively formed corresponding to portions where the plurality of solder balls 68 of the BGA package 54 are joined. Further, a terminal portion 80 is provided corresponding to each of the concave portions 78, and a distal end surface of each terminal portion 80 is exposed on the bottom surface of the corresponding concave portion 78. Each terminal section 80
Although not shown, is electrically connected as required to a circuit pattern provided on the circuit board 52. The resist layer 76 can also be formed by applying the resist layer 76 to the surface of the substrate body 73 and the circuit pattern as required.

The BGA package 54 is mounted on the circuit board 52 as follows. As can be understood from FIG. 2, the BGA package 54 is first placed on the circuit board 52 so that the tips of the plurality of solder balls 68 of the BGA package 54 are accommodated in the corresponding recesses 78 of the resist layer 76 of the circuit board 52. To a predetermined position. And
In this state, for example, hot air is blown to blow the solder balls 6.
8 is melted and reflow soldered.

When the BGA package 54 is electrically connected to the circuit board 52 in this way, as shown in FIG. 2, the terminal portions 80 of the circuit board 52 and the terminal portions 72 of the BGA package 54 are connected via the molten solder balls 68. The solder balls 68 are solidified to form a solder joint 82
Becomes Thus, the chip 58 of the BGA package 54 is connected to the circuit pattern of the circuit board 52 via the bonding wires 60, the pattern of the chip carrier board 56, the terminal 72, the solder joint 82, and the terminal 80 of the circuit board 52. (Not shown).

In the state where the BGA package 54 is mounted on the circuit board 52, the plurality of solder joints 82 are formed in the corresponding recesses 70, 7 of the resist layers 66, 76.
8 to be isolated and insulated. Therefore, when the solder ball 68 is melted, the adjacent solder joint 8
Short circuit between the two is reliably prevented by the resist layers 66 and 76. In addition, this allows the solder balls 68 of the BGA package 54 to be formed relatively large, so that the solder balls 68 and the terminal portions 80 of the circuit board 52 can be securely connected, resulting in a so-called open state. Can be prevented. Therefore, the bonding of the BGA package to the circuit board 52 is ensured, and by assembling such a circuit board structure to an electronic device, it is possible to prevent a failure or malfunction caused by a poor bonding of the circuit board structure. Can be. Note that the resist layers 76 and 6 of the circuit board 52 and the BGA package 54
The thickness of 6 can be, for example, about 100 to 200 μm.

In the above-described embodiment, the resist layers 66 and 76 are provided on the surfaces of the chip carrier substrate 56 and the circuit substrate 52 of the BGA package 54, respectively. It is sufficient to provide only one of the resist layers 56, and even in this case, the same effect as described above can be achieved.

In the above embodiment, the chip carrier substrate 56 of the BGA package 54 and the circuit board 5
Although the resist layers 66 and 76 are provided on the second substrate body 73, instead of the resist layers 66 and 76, a resin material is applied to the chip carrier substrate 56 and / or the substrate body 73 by printing or coating such as silk printing. The insulating layer may be formed by such means, and the same concave portion as described above may be formed in the insulating layer, and the same effect can be achieved in such a configuration. It should be noted that such printing or coating has a feature that it can be easily formed on an assembly line or the like as necessary.

FIG. 3 is a sectional view showing a second embodiment of the circuit board structure according to the present invention in a state before it is electrically connected. In the circuit board structure of the second embodiment, an insulating spacer is used as an insulating member instead of the resist layer, and the other configuration is substantially the same as the configuration of the first embodiment. Are denoted by the same reference numerals, and description thereof is omitted.

Referring to FIG. 3, the circuit board structure according to the present embodiment includes a circuit board 52 similarly to the first embodiment, and a predetermined circuit pattern ( (Not shown). The BGA package 54 mounted on the circuit board 52 includes a chip carrier substrate 56 and a chip 58, and the lower surface of the chip carrier substrate 56 (the surface connected to the circuit substrate 52).
, A plurality of solder balls 68 are provided in an array in the vertical and horizontal directions corresponding to respective terminal portions (not shown) as input / output terminals.

The insulating member for accommodating the solder balls 68 is constituted by a spacer 82 interposed between the circuit board 52 and the chip carrier board 56. In the present embodiment, the spacer 82 is made of a resin material. Is formed from. The spacer 82 includes the chip carrier substrate 56
A plurality of through holes 84 for accommodating the solder balls 68 are formed corresponding to the respective solder balls 68.
The spacer 82 can be formed of another insulating material, for example, ceramic, rubber, or the like, instead of the resin material.

The surface of the substrate body 73 (the surface connected to the BGA package 54) is
A plurality of solder pads 86 are provided corresponding to the plurality of solder balls 68, respectively. These solder pads 86 are electrically connected to a circuit pattern (not shown) provided on the substrate body 73.

The BGA package 54 is mounted on the circuit board 52 as follows. That is, the spacer 82 is held in a predetermined positional relationship with respect to the BGA package 54, and the corresponding solder ball 68 is positioned in the through hole 84 of the spacer 82. In this state, the solder balls 68 projecting from the through holes 84 of the spacers 82 are positioned on the corresponding solder pads 86 of the circuit board 52, and the BGA package 5 is mounted on the circuit board 52 via the spacers 82.
4 is placed. In this state, the solder ball 68 is melted by reflow soldering and fused to the solder pad 86, and a solder joint is formed in the same manner as in the first embodiment. As a result, the chip 58 of the BGA package 54 is electrically connected to the circuit pattern (not shown) of the circuit board 52 via the bonding wire 60, the pattern (not shown) of the chip carrier substrate 56, and the solder joint. Connected.

In such a bonding state, as will be easily understood, a solder bonding portion for electrically bonding the circuit board 52 and the BGA package 54 is located in the through hole 84 of the spacer 82, and this spacer 82 Thus, the solder joints are insulated and isolated, and short-circuiting between adjacent solder joints is reliably prevented.

When such a spacer 82 is used as an insulating member, when the BGA package is mounted on a conventional circuit board, it is only necessary to simply interpose the spacer 82 between the two, and the insulation is relatively easily and easily secured. be able to.

In this embodiment, similarly to the first embodiment, a resist layer, a printed or coated insulating layer can be applied to the surface of the circuit board 52 and / or the chip carrier substrate 56. In such a case, the thicknesses of the resist layer and the insulating layer are formed thinner than in the first embodiment.

FIG. 4 is a cross-sectional view showing a third embodiment of the circuit board structure according to the present invention in a state before it is electrically connected. In the third embodiment, an intermediate circuit board is used in place of the spacer 82 to ensure insulation.
Other configurations of this embodiment are substantially the same as those of the above-described second embodiment, and the same members are denoted by the same reference numerals and description thereof will be omitted. Note that, in the present embodiment, the circuit board 52 in the second embodiment functions as a base circuit board.

Referring to FIG. 4, a circuit board structure according to the present embodiment includes a base circuit board 52 provided with a predetermined circuit pattern (not shown) and a BGA electrically connected to the circuit pattern. It is composed of a package 54 and an intermediate circuit board 88. The base circuit board 52 and the BGA package 54 are the same as those of the above-described embodiment. The intermediate circuit board 88 is a base circuit board 52
And the chip carrier substrate 56 of the BGA package 54. The intermediate circuit board 88 is, for example, an intermediate board body 8 made of an insulator such as a phenol resin.
9 is provided on the intermediate substrate body 89 so as to correspond to each solder ball 68 of the chip carrier substrate 56.
A plurality of through holes 90 for accommodating the holes 8 are formed. An intermediate circuit pattern 92 is provided on the surface of the outer peripheral portion of the intermediate substrate main body 89 (the surface of the portion where the through hole 90 is not formed). The intermediate circuit pattern 92 can be formed on the lower surface of the intermediate substrate main body 89, or on both the upper surface and the lower surface.

In such a circuit board structure, for example, the intermediate circuit board 88 is mounted on the base circuit board 52 as required, and the circuit patterns of the two circuit boards 52 and 88 are electrically connected as required. You. Then, BG
The solder balls 68 of the A package 54 are
8, the base circuit board 5
Two corresponding solder pads 86 are located. Then, in such a state, the reflow soldering is performed, and the solder balls 68 are melted, so that the BGA package 54 is electrically connected to the base circuit board 52 via the solder joints as in the above-described embodiment. Connected.

In such a joined state, the solder joint is accommodated in the through hole 84 of the intermediate circuit board 88,
Since they are insulated and isolated from each other, a short circuit between adjacent solder joints is reliably prevented.

Further, in this embodiment, the intermediate circuit board 8
Since 8 is used, a part of the circuit pattern can be provided as the intermediate circuit pattern 92, whereby the size of the base circuit board 52 can be reduced.

In this embodiment, similarly to the first embodiment, a resist layer, an insulating layer formed by printing or coating may be provided on the surface of the base circuit board 52 and / or the chip carrier board 56.

In this embodiment, one intermediate circuit board is provided between the base circuit board 52 and the BGA package 54.
However, two or three or more pieces may be interposed.

Although various embodiments of the circuit board structure according to the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and corrections can be made without departing from the scope of the present invention. Is possible.

[0043]

According to the present invention, an electrical insulating member is provided on the surface of the circuit board and / or the chip carrier substrate, and the insulating member has a ball corresponding to the solder ball for accommodating a part thereof. Is provided. Therefore, when the BGA package is mounted on the circuit board and the solder balls are melted, the solder joints between the solder balls of the BGA package and the circuit board are isolated from each other by the insulating member, and the short circuit between adjacent solder joints is prevented. Is done. In addition, since the solder balls can be formed relatively large, the solder balls and the circuit board are prevented from being electrically connected and opened.

According to the present invention, the insulating member is formed of the resist layer, and the resist layer is provided with the concave portion corresponding to the solder ball, so that the solder joint between the solder ball of the BGA package and the circuit board is formed by the resist. Each layer is insulated and isolated. Such a resist layer,
A resist layer formed on the surface of a circuit board and / or a chip carrier substrate can be used.

According to the present invention, the insulating member comprises a spacer interposed between the circuit board and the chip carrier substrate, and the spacer has a through hole corresponding to the solder ball. Therefore, when mounting the BGA package on the circuit board, a spacer may be interposed between them.
By thus interposing the spacer, the solder joint between the solder ball and the circuit board can be insulated and isolated from each other by the spacer.

According to the present invention, the insulating member is formed from a printed or applied insulating layer, and the insulating layer has a recess corresponding to the solder ball. Therefore, before mounting the BGA package, the insulating layer may be formed by printing or coating. For example, the insulating layer can be easily formed on a manufacturing assembly line, and thus, the solder joint between the solder ball and the circuit board can be formed. The parts can be respectively insulated and isolated by an insulating layer.

Further, according to the present invention, the intermediate circuit board is interposed between the base circuit board and the chip carrier board,
Through holes are formed in the intermediate circuit board in correspondence with the solder balls. Therefore, by mounting the BGA package on the circuit board via the intermediate circuit board, the solder joints between the solder balls and the circuit board can be insulated and isolated from each other by the intermediate circuit board. In addition, by interposing the intermediate circuit board in this way, a part of the circuit pattern of the circuit board can be formed on the intermediate circuit board, whereby the entire circuit board structure can be downsized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a circuit board structure according to the present invention in a state before electrical connection.

FIG. 2 is a sectional view showing a state in which the circuit board structure of FIG. 1 is electrically connected.

FIG. 3 is a sectional view showing a second embodiment of the circuit board structure according to the present invention in a state before being electrically connected.

FIG. 4 is a cross-sectional view showing a third embodiment of a circuit board structure according to the present invention in a state before electrical connection.

FIG. 5 is a cross-sectional view illustrating a bonding failure in a conventional circuit board structure.

[Explanation of symbols]

 2,52 Circuit board (base circuit board) 4,54 BGA package 6,56 Chip carrier board 8,58 Chip 14,68 Solder ball 18,82 Solder joint 66,76 Resist layer 70,78 Recess 72,80 Terminal 82 spacer 84, 90 through hole 88 intermediate circuit board

Claims (5)

[Claims] 1. A circuit board provided with a predetermined circuit pattern, and a BGA package electrically connected to the circuit pattern of the circuit board, wherein the BGA package includes a chip carrier board, and the chip carrier board. A circuit board structure having a chip mounted on the chip and solder balls electrically connected to the chip, wherein an electric insulating member is provided on a surface of the circuit board and / or the chip carrier board; A circuit board structure, wherein a concave portion for accommodating a part of the solder ball is provided in the insulating member. 2. The semiconductor device according to claim 1, wherein the insulating member includes a resist layer provided on a surface of the circuit board and / or the chip carrier substrate, and the resist layer has the recess corresponding to the solder ball. The circuit board structure according to claim 1, wherein: 3. The insulating member comprises a spacer interposed between the circuit board and the chip carrier board, wherein the spacer has a through hole corresponding to the solder ball. The circuit board structure according to claim 1. 4. The insulating member is formed of an insulating layer printed or applied on a surface of the circuit board and / or the chip carrier substrate, and the concave portion is provided in the insulating layer corresponding to the solder ball. The circuit board structure according to claim 1, wherein 5. A base circuit board provided with a predetermined circuit pattern, an intermediate circuit board and a BGA package electrically connected to the circuit pattern of the base circuit board, wherein the BGA package is a chip carrier board. And a chip mounted on the chip carrier substrate, and a solder ball electrically connected to the chip, wherein the intermediate circuit substrate is interposed between the base circuit substrate and the chip carrier substrate, A circuit board structure, wherein a through hole is formed in the intermediate circuit board corresponding to the solder ball.