JP2001053411A - Method for fixing mounting member to printed board and fixing structure thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent protrusion of an underfill and roll-up formation of bubbles by bonding and fixing a mounting member (area terminal package) to a printed board with the underfill. SOLUTION: As shown in Figures (A1), (A2), a through-hole 5a is formed in advance on a printed board 5. As shown in figure (B), an area terminal package 1 is positioned below the printed board 5, and the through-hole 5a is covered from the lower side. When an underfill 4 as an adhesive agent having fluidity is poured from the through-hole 5a, the underfill 4 flows into a gap between the area terminal package 1 and the printed board 5 and the gap is filled with the underfill 4 and hardened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for fixing a member mounted on a printed circuit board with an adhesive, and a structure for fixing the same.

[0002]

2. Description of the Related Art FIG. 4 shows a prior art for fixing an area terminal package as an example of a mounting member to a printed circuit board with an adhesive.
(A) is a cross-sectional view schematically illustrating a state in which an underfill as an adhesive is applied, and (B) is a plane schematically illustrating a state in an initial step of applying an underfill as an adhesive. FIG. The area terminal package to be symmetrical in the present invention is a ball grid array (BG).
A) and a chip scale package (CSP). In FIG. 4, reference numeral 1a denotes the body of the area terminal package 1, which is a package-formed member. What is indicated by reference numeral 1b is a solder bump for electrically connecting and conducting. The area terminal package 1 is mechanically connected to and held by the printed board 2 via the solder bumps 1b.
However, since this alone is insufficient in strength, in order to complete the ability to withstand a possible impact load during use, bonding with a fluid adhesive (commonly known as underfill in the industry) 4 is used.・ Fixed. In this conventional example, an underfill 4 is applied by a syringe 3 (see FIG. 4A). Since the solder bump 1b acts as a spacer between the main body 1a and the printed circuit board 2 to form a gap g, the underfill 4 having fluidity flows into the gap g, Thereafter, the area terminal package 1 is solidified and fixed to the printed circuit board 2.

[0003]

According to the prior art described with reference to FIG. 4 described above, when a mounting member is bonded and fixed to a printed circuit board, "sticking out of adhesive"
The technical problem of "bubble formation" arises. Not only when using an area terminal package as a mounting member, but also when mounting electronic components, when mounting package components that do not include electronic components, or when mounting a sub-board smaller than the printed board, The above-mentioned problems of bleeding and bubbles are caused. FIG. 5 is a view showing "smearing out" in bonding and fixing an underfill of a printed circuit board mounted product,
It is shown for explaining "bubble formation",
(A) is a schematic plan view of the initial state of the underfill application, similar to FIG. 4 (B), and FIG.
(C) and (D) are schematic plan views sequentially depicting the progress of the underfill coating process, and (D) shows the occurrence of blemishes and bubbles when the coating process is completed. ing. As the flow area of the underfill indicated by spots expands as shown in (A) to (D), it is formed around the bubbles 4a and formed near the portion where the underfill 4 is poured. The large fins 4b are formed, and the small fins 4c and 4d are formed in other places.

When the bubbles 4a are generated, the area corresponding to the area of the bubbles cannot achieve the effect of bonding and fixing by underfill, so that the strength of the bonding and fixing is reduced and reliability is impaired. In addition, when the above-mentioned fins 4b to 4d are generated, the underfill is wasted and the material cost is increased, and the appearance is impaired and the commercial value is reduced. Thus, increasing the weight of the entire printed circuit board is a serious problem. For example, printed circuit boards for portable telephones are pursuing weight reduction in milligram units, so that underfilling can not be ignored.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a technique for bonding and fixing printed circuit board mounting members, which can prevent underfill bleeding and bubble formation. And

[0006]

The basic principle of the present invention created to achieve the above object will be briefly described with reference to FIG. 1 corresponding to the embodiment. That is, the technique of bonding and fixing the mounting member (the area terminal package in this example) 1 to the printed circuit board 5 by the underfill 4 is improved to prevent underfill bleeding and air bubble entrapment. Therefore, as shown in (A1) and (A2), a through hole 5a is provided in the printed board 5 in advance, and as shown in (B), the area terminal package 1 is positioned below the printed board 5 and The through hole 5a is covered from below. When the underfill 4 which is an adhesive having fluidity is poured from above the through hole 5a, the underfill 4 flows into the "gap between the area terminal package 1 and the printed board 5" and fills it. And solidify.

[0007] Based on the principle described above, claim 1
The configuration of the invention method according to the present invention, a through-hole is provided in advance on a printed board, and an electronic component is positioned so as to cover the through-hole, and a gap is formed between the electronic component and the printed board. Filling the gap with the adhesive by injecting an adhesive having fluidity through the through hole with the printed circuit board positioned on the upper side and the electronic component positioned on the lower side. Features. According to the method of the first aspect described above, the adhesive is not applied to the “surface on which the electronic component faces the printed circuit board” from the peripheral portion as in the prior art, but passes through the through hole of the printed circuit board. "The surface where the electronic components face the printed circuit board"
Since the adhesive flows into the vicinity of the center of the surface, the adhesive flows from the vicinity of the center of the above-mentioned surface toward the periphery. For this reason, there is no possibility that large peeling may occur at the peripheral portion of the above-described surface as in the related art. Further, since the adhesive flows radially from the central portion to the peripheral portion as described above, there is no possibility that air bubbles may be trapped near the central portion. As described above, the operation of pouring the adhesive into the central part of the electronic component has been made possible for the first time by a novel technique unique to the present invention, in which a through hole is provided in a printed circuit board.

According to a second aspect of the present invention, there is provided a method for mounting a packaged component having solder bumps or similar protrusions on a printed circuit board. A small through hole is also provided at the mounting position of the printed circuit board, and the main body of the component is positioned on the lower side of the printed circuit board, opposed to the periphery of the through hole, and the protrusion is printed. By making contact with the lower surface of the board, a gap is formed between the periphery of the projecting portion of the package of the component and the printed board, and the fluidity is transferred from the through hole of the printed board into the gap. It is characterized in that a predetermined amount of the adhesive is poured and solidified. According to the method of the present invention described above, the adhesive is not applied from the peripheral portion to the "surface on which the electrical component faces the printed board" as in the prior art, but passes through the through hole of the printed board. Then, the adhesive flows into the vicinity of the center of the “surface where the electrical component faces the printed circuit board”, so that the adhesive flows from the vicinity of the center of the above-mentioned surface toward the peripheral portion. For this reason, there is no possibility that large peeling may occur at the peripheral portion of the above-described surface as in the related art. Further, since the adhesive flows radially from the central portion to the peripheral portion as described above, there is no possibility that air bubbles may be trapped near the central portion. As mentioned above, the operation of pouring the adhesive into the center of the electrical component is to provide a through hole in the printed circuit board,
This is made possible for the first time by a novel technique unique to the present invention.

According to a third aspect of the present invention, there is provided a mounting and fixing method for mounting and fixing a “comparatively formed, relatively small sub-board” on a relatively large printed board. On the relatively large printed circuit board,
Providing a `` through hole or opening smaller than the contour shape of the relatively small sub-board '', and positioning the printed board above the sub-board, facing the sub-board to the through-hole or opening of the printed board, and While holding the sub-substrate in a state where the sub-substrate is opposed to and separated from the printed board substantially in parallel, a flowable adhesive is injected from the through-hole or opening, and the printed board and the sub-board are opposed to each other. It is characterized in that the gap between the portions is filled with the adhesive, and the adhesive is solidified. According to the method of the third aspect described above, the adhesive is not applied from the peripheral portion to the “surface on which the sub-board faces the printed board” as in the related art, but passes through the through-hole of the printed board. Then, the adhesive flows into the vicinity of the center of the “surface where the sub-board faces the printed circuit board”, so that the adhesive flows from the vicinity of the center of the above-mentioned surface toward the periphery. For this reason, there is no possibility that large peeling may occur at the peripheral portion of the above-described surface as in the related art. If the sub-substrate is relatively large, the through hole can be an opening, but the principle operation is the same. Further, since the adhesive flows radially from the central portion to the peripheral portion as described above, there is no possibility that air bubbles may be trapped near the central portion. As described above, the operation of pouring the adhesive into the central portion of the sub-board is made possible for the first time by a novel technique unique to the present invention, in which a through-hole is provided in a printed board.

According to a fourth aspect of the present invention, in the structure in which the electronic component is fixed to the printed board, the surface of the printed board facing the electronic component is smaller than the contour shape of the electronic component. A through hole is provided, and a part or a large part of a surface of the electronic component facing the printed circuit board is formed with a surface opposed to and separated from the printed circuit board and substantially parallel to the printed circuit board. An adhesive is filled between an area around the through hole of the printed board and a surface of the electronic component facing and separated substantially in parallel with the printed board. According to the fourth aspect of the present invention, since the through hole is provided at a position where the printed circuit board faces the electronic component, the operation of injecting the adhesive through the through hole is performed quickly and easily. Can work and is excellent in workability. The adhesive poured from the through hole flows into the vicinity of the center of the “surface where the electronic component faces the printed circuit board” and flows toward the periphery of the surface. As long as the injection amount is not excessive, there is no danger of overflow from the periphery of the above-mentioned surface and bleeding. Furthermore, as described above, since the adhesive injected near the central portion flows radially toward the peripheral portion, there is no danger of entraining bubbles, so that a fixing structure with stable adhesive strength can be easily configured at low cost. can do.

According to a fifth aspect of the present invention, there is provided a package-molded component, wherein the package-molded product has a mounting member on a surface of which a solder bump or a plurality of protrusions similar thereto are formed. In the structure fixed to the printed circuit board, a through-hole is provided in the “place facing the package molded article” of the printed circuit board, and the solder bumps or projections of the package molded article are formed on the printed circuit board surface. Abuts and functions as a spacer, a gap is formed between the printed board and the package molded product, and at the peripheral portion of the through hole, the gap is filled with an adhesive. Features. According to the structure of the fifth aspect of the present invention described above, since the through hole is provided at a position where the printed board faces the mounting component, the operation of injecting the adhesive through the through hole is performed quickly and easily. Can work and is excellent in workability. The adhesive poured from the through-hole flows into the vicinity of the center of the “surface on which the mounted component faces the printed circuit board” and flows toward the periphery of the surface. As long as the injection amount is not excessive, there is no danger of overflow from the periphery of the above-mentioned surface and bleeding. further,
As described above, since the adhesive injected near the central portion flows radially toward the peripheral portion, there is no danger of entrapping air bubbles. Therefore, a fixing structure with stable adhesive strength can be easily configured at low cost. Can be.

According to a sixth aspect of the present invention, there is provided a structure in which an auxiliary board formed separately from the printed board is mounted and fixed on the printed board. The sub-substrate is substantially parallel to and separated from the sub-substrate, and a through-hole or an opening is provided in a part of the area where the printed board is opposed to the sub-substrate, and An adhesive is filled in a gap between the through hole or the periphery of the opening and the sub-substrate, and is solidified. According to the structure of the invention of claim 6 described above, since the through hole is provided at a position where the printed board faces the sub-board,
The operation of injecting the adhesive through the through hole can be performed quickly and easily, and the workability is excellent. When the sub-substrate is relatively large, the above-mentioned through hole can be enlarged to the extent that it can be called an opening. The adhesive poured from the through hole flows near the center of the “surface where the sub-board faces the printed circuit board” and flows toward the periphery of the surface. As long as the injection amount is not excessive, there is no danger of overflow from the periphery of the above-mentioned surface and bleeding. Furthermore, as described above, since the adhesive injected near the central portion flows radially toward the peripheral portion, there is no danger of entraining bubbles, so that a fixing structure with stable adhesive strength can be easily configured at low cost. can do.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic explanatory view showing one embodiment of the present invention, in which (A1) is a side sectional view before injecting an adhesive, and (A2) is a bottom surface before injecting an adhesive. FIG. 3B is a side cross-sectional view during the injection of the adhesive. This figure 1 (A1),
As shown in (A2), the main body 1a of the area terminal package 1 is formed into a substantially rectangular package,
The solder bumps 1b are formed on one of the surfaces, and the electrical connection to the printed circuit board 5 has been completed, but the mechanical fixing strength is insufficient. A through-hole 5 a is formed in the printed circuit board 5 so as to face the center of the main body 1 a of the area terminal package 1. The solder bumps 1b perform a function similar to a spacer, and the main body 1a of the area terminal package 1 and the printed board 5
As shown in 1), they are opposed to and separated from each other in parallel with a spacing dimension g therebetween. Although illustration is omitted, solder bump 1
If b does not easily function as a spacer, “a plurality of protrusions that can function as a spacer and have a shape similar to that of the solder bump 1b” may be provided on the main body 1a. In short, the main body 1a is opposed to and separated from the printed circuit board substantially in parallel, and also near the center of the main body 1a (it does not need to be strictly at the center; it is desirable to be away from the periphery). At least, a through hole may be formed in the printed circuit board 5. The state shown in FIG. 1A is inverted upside down from the state shown in FIG. However, it is not an essential requirement to invert the state from the state of (A1), and the state of FIG. 1B may appear from the beginning. Using the cylinder 3, an underfill 4 which is a fluid adhesive is injected into the through hole 5a. The injected underfill 4 flows and spreads to fill the gap g.

FIG. 2 shows a state in which the underfill injected from the through hole of the printed circuit board flows as shown in FIG. 1B and spreads between the printed circuit board and the area terminal package. (A) shows a state at the initial stage of injection, (B) and (C) show a state in which the underfill spreads sequentially, and (D) shows a state in which the flow has finished. I have. As understood from the above (A) to (C), it is provided at the center of the area terminal package 1 (specifically, at the center of the area where the area terminal package 1 faces the printed circuit board 5). The underfill 4 injected into the through hole 5a flows radially from the center of the area terminal package 1 toward the periphery. For this reason, there is no possibility that air bubbles may be trapped in the underfill 4 as in the prior art, and the bonding strength is high and the bonding reliability is high. Since it is very difficult to nondestructively inspect whether or not bubbles are formed, the practical value of high reliability as described above is enormous. Further, since the underfill 4 flows from the center to the periphery as described above, if the amount of the underfill 4 to be injected into the center is regulated so as not to be excessive, the underfill 4 becomes It is possible to prevent a problem that the area terminal package 1 overflows from the peripheral portion and bleeds out. In the example shown in FIG. 2, as shown in FIG. 2D, the underfill 4 is diffused and flown while leaving margins L and L 'for eliminating the possibility of bleeding.

The area terminal package 1 in the embodiment of FIG. 1 is specifically a ball grid array (BGA).
Alternatively, although the present invention is a chip scale package (CSP), the present invention is not limited to the area terminal package 1 and can be applied to all electronic components in a broad sense. Mount any electronic components on the printed circuit board,
In the case of bonding and fixing, the presence of the solder bump 1b is not an essential component. For example, when considering with reference to FIG. 1B, the electronic component may be opposed to and separated from the printed circuit board substantially in parallel as indicated by a gap g in the figure. Considering the above-mentioned FIG. 1, the area terminal package 1 is referred to as a “packaged mounted product”.
Can also be seen as an example. That is, the present invention can be applied and fixed to a printed circuit board by applying the present invention even if it is not necessarily an electronic component, but is, for example, a simple terminal member (terminal for connection conduction). When the present invention is applied to a package molded product in a broad sense, it is desirable that the package molded product is provided with a solder bump or a protrusion having a shape and size similar to the solder bump, and the solder bump or the protrusion acts as a spacer. As a result, a gap as shown as a gap g in FIG. 1B is formed (that is, the gap is slightly separated from each other and substantially parallel to each other), and the adhesive is poured into this gap to be solidified.

FIG. 3 shows an embodiment different from the above-mentioned FIG. 1, in which a relatively small sub-substrate 7 mounted on a relatively large main printed circuit board 6 is adhered and fixed by underfill. It is sectional drawing of a state. The main printed circuit board 6 has a through-hole 6a facing the sub-board 7. The sub-board 7 is a board provided as an auxiliary, and is relatively small compared to the main printed board 6. Here, the auxiliary substrate means that it cannot be used alone, and does not limit the functional characteristics and capacity. As a general rule when applying the present invention, it is not preferable that the shape and size of the through hole be larger than the contour shape of the mounting member. However, when the shape of the sub-substrate 7 in the present embodiment (FIG. 3) is relatively large, the through-hole 6a can be enlarged to the extent that it should be called an “opening”. In this case, both the through hole and the opening are equivalent on the working surface. In the embodiment shown in FIG.
By flowing a predetermined amount of the underfill 4 through the through-hole or opening 6a in a state where the sub-substrate 7 is separated from the main printed circuit board 6 substantially in parallel with and separated from the main printed circuit board 6, the sub-board 7 is It can be adhesively fixed to the printed circuit board 6.

[0017]

As described above, according to the embodiment of the present invention, the structure and function of the present invention are clarified. Instead of applying adhesive from the peripheral part as in the conventional technology, the adhesive flows through the through hole of the printed circuit board and near the center of the "surface where the electronic component faces the printed circuit board", The agent flows from near the center of the surface to the periphery. For this reason, there is no possibility that large peeling may occur at the peripheral portion of the above-described surface as in the related art. Further, since the adhesive flows radially from the central portion to the peripheral portion as described above, there is no possibility that air bubbles may be trapped near the central portion. As described above, the operation of pouring the adhesive into the central part of the electronic component has been made possible for the first time by a novel technique unique to the present invention, in which a through hole is provided in a printed circuit board.

According to the second aspect of the present invention, the adhesive is not applied from the peripheral portion to the "surface on which the electric component faces the printed board" as in the prior art, but through the through hole of the printed board. Since the adhesive flows into the vicinity of the center of the "surface on which the electrical component faces the printed circuit board", the adhesive flows from the vicinity of the center of the above-mentioned surface toward the peripheral portion. For this reason, there is no possibility that large peeling may occur at the peripheral portion of the above-described surface as in the related art. Further, since the adhesive flows radially from the central portion to the peripheral portion as described above, there is no possibility that air bubbles may be trapped near the central portion. As mentioned above, the operation of pouring the adhesive into the center of the electrical component is to provide a through hole in the printed circuit board,
This is made possible for the first time by a novel technique unique to the present invention.

According to the third aspect of the present invention, the adhesive is not applied from the peripheral portion to the "surface on which the sub-board faces the printed board" as in the prior art, but through the through-hole of the printed board. Since the adhesive flows into the vicinity of the center of the “surface where the sub-board faces the printed circuit board”, the adhesive flows from the vicinity of the center of the above-mentioned surface toward the periphery. For this reason, there is no possibility that large peeling may occur at the peripheral portion of the above-described surface as in the related art. If the sub-substrate is relatively large, the through hole can be an opening,
The principle operation is the same. Furthermore, as described above, the adhesive flows radially from the central portion toward the peripheral portion,
There is no danger of bubbles being trapped near the center. As described above, the operation of pouring the adhesive into the central portion of the sub-board is made possible for the first time by a novel technique unique to the present invention, in which a through-hole is provided in a printed board.

According to the fourth aspect of the present invention, since the through hole is provided at a position where the printed circuit board faces the electronic component, the operation of injecting the adhesive through the through hole can be performed quickly and easily. And excellent workability.
The adhesive poured from the through hole flows into the vicinity of the center of the “surface where the electronic component faces the printed circuit board” and flows toward the periphery of the surface. As long as the injection amount is not excessive, there is no danger of overflow from the periphery of the above-mentioned surface and bleeding. Furthermore, as described above, since the adhesive injected near the central portion flows radially toward the peripheral portion, there is no danger of entraining bubbles, so that a fixing structure with stable adhesive strength can be easily configured at low cost. can do.

According to the fifth aspect of the present invention, since the through hole is provided at the position where the printed circuit board faces the mounting component, the operation of injecting the adhesive through the through hole can be performed quickly and easily. And excellent workability.
The adhesive poured from the through-hole flows into the vicinity of the center of the “surface on which the mounted component faces the printed circuit board” and flows toward the periphery of the surface. As long as the injection amount is not excessive, there is no danger of overflow from the periphery of the above-mentioned surface and bleeding. Furthermore, as described above, since the adhesive injected near the central portion flows radially toward the peripheral portion, there is no danger of entraining bubbles, so that a fixing structure with stable adhesive strength can be easily configured at low cost. can do.

According to the structure of the sixth aspect of the present invention, since the through hole is provided at the position where the printed board faces the sub-board, the operation of injecting the adhesive through the through hole can be performed quickly and easily. And excellent workability.
When the sub-substrate is relatively large, the above-mentioned through hole can be enlarged to the extent that it can be called an opening. The adhesive poured from the through hole flows near the center of the “surface where the sub-board faces the printed circuit board” and flows toward the periphery of the surface. As long as the injection amount is not excessive, there is no danger of overflow from the periphery of the above-mentioned surface and bleeding. Furthermore, as described above, since the adhesive injected near the central portion flows radially toward the peripheral portion, there is no danger of entraining bubbles, so that a fixing structure with stable adhesive strength can be easily configured at low cost. can do.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing one embodiment of the present invention, in which (A1) is a side sectional view before injecting an adhesive, and (A2).
FIG. 3 is a bottom view before the adhesive is injected, and FIG. 2B is a side cross-sectional view during the adhesive injection.

FIG. 2 is a schematic diagram illustrating a state in which an underfill injected from a through hole of a printed circuit board flows as shown in FIG. 1B and spreads between the printed circuit board and an area terminal package. (A) shows the state at the beginning of the injection, (B) and (C) show the state in which the underfill spreads sequentially, and (D) shows the state in which the underfill has finished flowing.

FIG. 3 is a cross-sectional view showing an embodiment different from the above-described FIG. 1, in which a relatively small sub-substrate 7 mounted on a relatively large main printed circuit board 6 is adhered and fixed by underfill. FIG.

FIG. 4 is a view for explaining a conventional technique of fixing an area terminal package as an example of a mounting member to a printed circuit board with an adhesive, and FIG. 4A shows an underfill as an adhesive; FIG. 3B is a cross-sectional view schematically illustrating a state in which the adhesive is being applied, and FIG. 2B is a plan view schematically illustrating an initial state of a step of applying an underfill as an adhesive.

FIGS. 5A and 5B are views for explaining “smearing out” and “bubble formation” in bonding and fixing an underfill of a printed circuit board mounted product, and FIG.
7A, 7B, 7C, and 7D are schematic plan views sequentially depicting the progress of the underfill application step, as in the case of FIG. This (D) shows the appearance of blemishes and bubbles when the coating step is completed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Area terminal package, 1a ... Body part, 1b ... Solder bump, 2 ... Printed circuit board, 3 ... Syringe, 4 ... Underfill, 4a ... Bubbles, 4b ...
c, 4d: small fins, 5: printed circuit board, 5a
... through-hole, 6 ... main printed board, 6a ... through-hole or opening, 7 ... sub-board.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yutaka Kuroshima 3-14-20 Higashinakano, Nakano-ku, Tokyo Kokusai Denki Co., Ltd. F-term (reference) 5E336 AA04 BB01 BC01 CC32 CC36 EE07 GG16 5E344 AA19 AA26 CC05 CC23 DD02 DD13 EE16 5F044 KK01 KK27 LL11 LL17 QQ03 RR18 5F061 AA01 BA04 CA04

Claims (6)

[Claims] A printed circuit board is provided with a through hole in advance, an electronic component is positioned so as to cover the through hole, and a gap is formed between the electronic component and the printed circuit board. The gap is filled with an adhesive by injecting an adhesive having fluidity through the through-hole in a state where the electronic component is positioned on the lower side on the upper side. And a method of fixing a mounting member to a printed circuit board. 2. A method of mounting a packaged component having solder bumps or similar protrusions on a printed circuit board, the method comprising: forming a through hole smaller than a contour shape of a packaged main body portion. And the main body of the component is positioned below the printed circuit board, and is opposed to the periphery of the through hole, and the protrusion contacts the lower surface of the printed circuit board. By doing so, a gap is formed between the periphery of the projecting portion of the package of the component and the printed board, and a predetermined amount of an adhesive having fluidity is poured from the through hole of the printed board into the gap. A method for fixing a mounting member to a printed circuit board, comprising solidifying the mounting member. 3. For a relatively large printed circuit board,
In a method of mounting and fixing a “comparatively configured, relatively small sub-board”, a “through hole or opening smaller than the contour shape of the relatively small sub-board” is provided on the relatively large printed board. The printed circuit board is positioned above the sub-board, the sub-board is opposed to a through hole or opening of the printed board, and the sub-board is kept substantially parallel to and separated from the printed board. Then, an adhesive having fluidity is injected from the through hole or the opening, and a gap between a portion where the printed board and the sub-substrate face each other is filled with the adhesive, and the adhesive is solidified. A method for fixing a mounting member to a printed circuit board, comprising: 4. A structure in which an electronic component is fixed to a printed circuit board, wherein a surface of the printed circuit board facing the electronic component is provided with a through hole smaller than a contour shape of the electronic component. A part or a large part of the surface of the component facing the printed circuit board is formed with a surface facing and separated from the printed circuit board and substantially parallel to the printed circuit board. A structure in which a mounting member is fixed to a printed circuit board, wherein an adhesive is filled between the area and a surface of the electronic component facing and separated substantially in parallel with the printed circuit board. 5. A structure in which a package-molded component having a plurality of protrusions similar to solder bumps formed on a surface of the package molded product is fixed to a printed circuit board. A through hole is provided at a “location facing the package molded product” of the printed circuit board, and solder bumps or projections of the package molded product function as spacers by contacting the printed circuit board surface. A gap is formed between the printed board and the package molded product, and the gap is filled with a solidified adhesive in a peripheral portion of the through hole, wherein the printed board is Structure where mounting members are fixed. 6. In a structure in which an auxiliary board formed separately from the printed board is mounted on and fixed to the printed board, a relatively large printed board and a relatively small sub-board are substantially separated. A through hole or an opening is provided in a part of the area where the printed circuit board faces the sub-board while being parallel to and separated from each other, and a sub-portion is formed with a peripheral portion of the through-hole or the opening of the printed board. A structure in which a mounting member is fixed to a printed board, wherein an adhesive is filled in a gap between the board and the board, and the adhesive is solidified.