JP7441613B2 - High density mounting module - Google Patents

Description

The present invention relates to a high-density mounting module, and particularly to a module in which electronic components are surface-mounted on a printed circuit board at high density.

2. Description of the Related Art As electronic device modules become smaller and lighter, individual electronic parts such as semiconductor elements and electronic components mounted thereon are being made smaller. In this type of module, a technique for surface mounting electronic components on a printed circuit board is employed in order to realize high-density mounting commensurate with the miniaturization of mounted components.

In modules that employ high-density surface mount technology, individual electronic components are mounted on a printed circuit board using solder reflow technology, ensuring mechanical strength to secure the electronic components to the printed circuit board, and It is possible to simultaneously reduce the electrical resistance between each connection terminal of the component and the conductive layer of the printed circuit board.

Japanese Patent Application Publication No. 10-335795

The above solder reflow technology uses a printing method to apply an appropriate amount of cream solder onto the mounting land of a printed circuit board, aligns and mounts the electronic component on the mounting land, and then heats the solder to melt the solder. By cooling, the solder solidifies and electrical connections are established while securing electronic components on the printed circuit board.

In this type of surface mount technology, when the solder is melted, the electronic components are suspended on the molten solder, so the electronic components move on the solder until it cools and solidifies. This may cause the device to shift from its original aligned and mounted position. As a technique for suppressing such positional deviation, for example, the technique described in Cited Document 1 has been proposed.

On the other hand, in order to ensure mechanical strength for fixing the electronic component to the printed circuit board, it is necessary to sufficiently form a solder fillet surrounding the connection terminal of the electronic component on the mounting land. To do this, it is necessary to supply a sufficient volume of solder on the mounting land to surround the connection terminals of the electronic components, which makes it easier for the electronic components to move when the solder melts. bring.

The present invention has been made in view of the above circumstances, and an object of the present invention is to sufficiently form a solder fillet surrounding the connection terminal of the electronic component on the mounting land, so that the electronic component can be soldered. and printed circuit boards are fixed with sufficient mechanical strength, and during solder reflow, electronic components are prevented from moving on the solder and shifting from their original positions where they were aligned and mounted. An object of the present invention is to provide a high-density mounting module having mounting position accuracy.

A high-density mounting module according to a first aspect of the present invention includes a printed circuit board having a plurality of lands, and an electronic component including a plurality of connection terminals mounted on the printed circuit board and connected to the plurality of lands. A mounted module, wherein the plurality of lands include a first notch and a second notch extending in directions opposite to each other in a first direction, and a second direction perpendicular to the first direction. A third notch and a fourth notch extending in opposite directions, extending from each side of the plurality of connection terminals of the electronic component to the surface of each land to which the connection terminals are connected. A solder fillet is formed that extends from the top.

According to a second aspect of the present invention, in the first aspect, the plurality of lands include lands in which no notch is arranged.

According to a third aspect of the present invention, in the first aspect, the plurality of lands include a land in which only one notch is arranged.

According to a fourth aspect of the present invention, in the first aspect, the plurality of lands includes at least four lands, and includes four lands in which only one notch is arranged.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, each of the first notch and the second notch is arranged on a separate land. , the separate lands are spaced apart from each other in a second direction.

According to a sixth aspect of the present invention, in any one of the first aspect to the fifth aspect, each of the third notch and the fourth notch are arranged on separate lands. , the separate lands are spaced apart from each other in a first direction.

According to a seventh aspect of the present invention, in any one of the first aspect to the sixth aspect, the plurality of lands include a fifth notch extending in the first direction and a second notch extending in the first direction. It further includes a sixth notch extending in the direction of.

A high-density mounting module according to an eighth aspect of the present invention includes a plurality of lands and a solder resist having a plurality of openings that cover the peripheral edges of each of the plurality of lands and are included in each area of the plurality of lands. , and an electronic component including a plurality of connection terminals mounted on the printed circuit board and connected to the plurality of lands, the module having a plurality of openings included in the plurality of lands. A first protrusion and a second protrusion that face each other in a first direction and each protrude inwardly, and a second protrusion that faces each other in a second direction orthogonal to the first direction and each protrudes inwardly. a third protrusion and a fourth protrusion that protrude in the direction, and extend from each side of the plurality of connection terminals of the electronic component to the surface of each land to which the connection terminals are connected. A solder fillet is formed.

According to the present invention, the solder fillet surrounding the connecting terminal of the electronic component is sufficiently formed on the mounting land, so that the electronic component is fixed to the printed circuit board with sufficient mechanical strength, and the electronic component This prevents the fixed position from moving on the melted solder during solder reflow and shifting from the original position where it was aligned and mounted, resulting in high-density mounting modules with good mounting position accuracy. can be provided.

FIG. 1 is a plan view of a first embodiment of a high-density mounting module of the present invention. It is a top view of the modification of 1st Embodiment of the high-density mounting module of this invention. FIG. 7 is a plan view of a further modification of the first embodiment of the high-density mounting module of the present invention. 4 is a cross-sectional view taken along line AA' in FIG. 3. FIG. 4 is a cross-sectional view taken along line BB' in FIG. 3. FIG. 4 is a cross-sectional view taken along line CC' in FIG. 3. FIG. FIG. 7 is a plan view of another modification of the first embodiment of the high-density mounting module of the present invention. FIG. 3 is a plan view of a second embodiment of the high-density mounting module of the present invention.

Hereinafter, various embodiments of the present invention will be described based on the drawings.

<First embodiment>
FIG. 1 shows a module 101 that is a first embodiment of the high-density packaging module of the present invention. The module 101 includes a printed circuit board 105 having a first land 111, a second land 112, and a third land 113. The printed circuit board 105 has a first connection terminal 151, a second connection terminal 152, and a third connection terminal connected to corresponding ones of the first land 111, the second land 112, and the third land 113. An electronic component 150 including a connection terminal 153 is mounted.

A first notch 121 extending in the first direction (X direction) is arranged in the first land 111, and a first notch 121 extending in the first direction (X direction) is arranged in the second land 112. A third notch 123 extending in the second direction (Y direction) is arranged. Further, the third land 113 has a second notch 122 extending in a direction opposite to the first notch 121 in the first direction (X direction), and a second notch 122 extending in a direction opposite to the first notch 121 in the first direction (X direction). A fourth notch 124 extending in a direction opposite to the third notch 123 is arranged.

In this first embodiment, when a force is generated during solder reflow to move the electronic component floating in the melted solder in the negative direction of the first direction (X direction), the first notch 121 suppresses movement of the first connection terminal 151 of the electronic component. Then, when a force to move the electronic component in the positive direction is generated, the second notch 122 suppresses the movement of the third connection terminal 153 of the electronic component.

Similarly, when a force is generated to move the electronic component in the negative direction (Y direction), the third notch 123 suppresses the movement of the connection terminal 152 of the electronic component and causes it to move in the positive direction. When a force is generated, the fourth notch 124 suppresses the movement of the third connection terminal 153 of the electronic component.

In this way, in order to prevent the electronic components floating in the molten solder from moving in parallel in the first direction (X direction) and in the second direction (Y direction), it is necessary to , at least two notches extending in opposite directions in a first direction (X direction), and a second direction (Y direction) orthogonal to the first direction (X direction). direction), and two cutouts extending in opposite directions to each other.

However, the movement of electronic components floating in molten solder is not limited to parallel movement; for example, when a force is generated to move the electronic components in the negative direction of the first direction (X direction), the first cut Although the notch 121 prevents the first connection terminal 151 of the electronic component from moving in the negative first direction (X direction), it prevents the entire electronic component from rotating around the first notch 121. This movement cannot be suppressed.

Similarly, for the second notch 122, third notch 123, and fourth notch 124, similarly to the first notch 121, each notch allows the electronic component to be moved in the corresponding direction. Although parallel movement of the connection terminals can be suppressed, rotation of the entire electronic component about each notch cannot be suppressed.

Regarding this movement of rotation, positional displacement can be suppressed by combining a plurality of notches. For example, the second notch 122 and the fourth notch 124 suppress and prevent the movement of the third connection terminal 153 from rotating clockwise around the first notch 121. . Regarding the movement of counterclockwise rotation, the movement of the second connection terminal 152 and the third connection terminal 153 is suppressed and prevented by the third notch 123 and the fourth notch 124, respectively. Ru.

In addition, when the movement is centered around the second notch 122, the movement of the first connection terminal 151 is caused by the first notch 121 for clockwise rotation, and the movement of the first connection terminal 151 is caused by the movement of the first connection terminal 151 by the third notch 123 for counterclockwise rotation. And the fourth notch 124 suppresses each movement of the first connection terminal 151 and the second connection terminal 152 .

In FIG. 1, a first land 111 in which a first notch 121 extending in a first direction (X direction) is arranged has a second notch 122 in a direction opposite to the first notch 121. The arranged third land 113, the first notch 121 and the second notch 122 are spaced apart from each other in the second direction (Y direction) orthogonal to the first direction (X direction) in which they extend. There is.

Further, the second land 112 in which the third notch 123 extending in the second direction (Y direction) is arranged has a fourth notch 124 in a direction opposite to the third notch 123. The third land 113, the third notch 123, and the fourth notch 124 are spaced apart from each other in the first direction (Y direction) orthogonal to the second direction (X direction) in which they extend.

Considering the suppression of misalignment not only in the parallel movement direction of the electronic component but also in the rotational direction, at least two notches extending in mutually opposing directions should be distributed and arranged on lands spaced apart from each other. is more preferred.

FIG. 2 shows a modification of the module 101 according to the first embodiment of the present invention. In this modification, in the module 101 shown in FIG. 1, the third notch 123 that was placed on the second land 112 is placed on the first land 111. The direction and orientation in which this third notch 123 extends are the same as the direction and orientation in which the third notch 123 shown in FIG. 1 extends. In this modification, no notch is arranged in the second land 112.

Also in this modification, the first land 111 in which the third notch 123 extending in the second direction (X direction) is arranged has a fourth notch in the direction opposite to the third notch 123. The third land 113 on which the third notch 124 and the fourth notch 124 are arranged are mutually arranged in the first direction (Y direction) orthogonal to the second direction (X direction) in which the third notch 123 and the fourth notch 124 extend. They are separated.

FIG. 3 shows a further modification of the module 101 of the first embodiment of the invention. In this further modification, in addition to the module 101 shown in FIG. A sixth notch 126 extending in the direction (X direction) and a seventh notch 127 extending in the second direction (Y direction) of the first land 111 are added.

The fifth notch 125 and the sixth notch 126 extend in directions facing each other in the first direction (X direction), and the seventh notch 127 extends between the fourth notch 124 and the second notch. Stretch in directions facing each other in the direction (Y direction).

In this further modification, in the negative direction of the first direction (X direction), the first notch 121 suppresses the movement of the first connection terminal 151, and the sixth notch 126 suppresses the movement of the third The movement of the connection terminal 153 is also suppressed. In the positive direction of the first direction (X direction), the second notch 122 and the fifth notch 125 suppress the movement of the third connecting terminal 153 and the second connecting terminal 152, respectively. do.

Regarding the negative direction of the second direction (Y direction), the third notch 123 and the seventh notch 127 suppress the movement of the second connection terminal 152 and the first connection terminal 151, respectively. Regarding the positive direction of the second direction (Y direction), movement of the electronic component is suppressed by the fourth notch 124, which is similar to the module 101 shown in FIG.

In addition, this further modification is configured to similarly suppress movement of the entire electronic component in an oblique direction. For example, movement in a diagonal direction (positive/positive direction) where the first direction (X direction) is positive and the second direction (Y direction) is also positive is caused by the movement of the second notch 122 and the fourth notch 124. suppresses and prevents movement of the third connection terminal 153.

Similarly, the movement in the positive/negative direction is suppressed by the third notch 123 and the fifth notch 125, and the movement in the negative/positive direction is suppressed by the fourth notch. The notch 124 and the sixth notch 126 suppress the movement of the third connection terminal 153, and the first notch 121 and the seventh notch 127 suppress the movement of the third connection terminal 153 in the negative/negative direction. movement of electronic components can be suppressed and movement of electronic components can be prevented.

In this way, if it is possible to suppress the parallel movement in the first direction (X direction) and the second direction (Y direction), and also to suppress the positional displacement in the four diagonal directions, it is possible to All rotational movement of parts can also be suppressed. This further modification has the effect of equally suppressing positional displacement in all directions.

4, 5, and 6 are cross-sectional views of the line segment AA' and the line segment BB' of the third land 113 and the line segment of the second land 112 shown in FIG. 3, respectively. FIG. 3 is a sectional view taken along line CC'. 4 and 5, a third land 113 is arranged on the printed circuit board 105, and a third connection terminal 153 of the electronic component 150 is soldered onto the third land 113.

Here, since the line segment AA' is the part where the second notch 122 and the sixth notch 126 are arranged, the third land 113 is located horizontally from the end of the third connection terminal 153. The amount of protrusion in the direction is small. Furthermore, since the solder that can be held when melted is limited to the third land 113, which is a conductive layer, there is only a small amount of melted solder that wraps around in the lateral direction of the end of the third connection terminal 153. Therefore, a thin solder layer 160 is formed on the surface of the third land 113 without forming a solder fillet.

On the other hand, the phenomenon in which the electronic component 150 is misaligned during the solder reflow process is caused by the electronic component 150 floating and moving on the molten solder. Therefore, unless the melted solder wraps around the end of the third connection terminal 153 in the lateral direction, the third connection terminal 153 will not move in the lateral direction, that is, in the A direction and the A' direction in FIG. Can not. Therefore, in the portion where the notch is arranged, the electronic component is prevented from moving toward the notch during solder reflow.

FIG. 5 is a cross-sectional view of the third land 113 in a portion where no notch is formed, and both ends of the third land 113 largely protrude from the third connection terminal 153 in the lateral direction. Therefore, the molten solder can sufficiently spread in the lateral direction of the end of the third connecting terminal 153, and the solder fillet can be formed from both end sides of the third connecting terminal 153 to the surface of the third land 113. 165 is formed.

In this way, by ensuring a sufficient amount of lateral protrusion of the third land 113 from both ends of the third connection terminal 153, the solder fillet 165 is formed, and the third connection terminal 153 and the third The mechanical strength for fixing the electronic component 150 to the land 113, that is, the mechanical strength for fixing the electronic component 150 to the printed circuit board 105 can be ensured.

FIG. 6 shows a cross-sectional view taken along the line CC' in which the second connection terminal 152 is arranged on the second land 112 on which the fifth notch 125 is arranged on one side. Similar to the third land 113, no solder fillet is formed in the vicinity of the fifth notch 125, and the solder fillet extends from the side surface of the second connection terminal 152 to the second land 112 in the area where there is no notch. A sufficient solder fillet 165 is formed.

As described above, in the portion where the notch is arranged in the land, movement of the electronic component 150 during solder reflow can be suppressed. Further, even on a land where a notch is arranged, a solder fillet that holds an electronic component with sufficient strength can be formed in areas other than the vicinity of the notch.

As described above, according to the first embodiment of the present invention, the solder fillet surrounding the connection terminal of the electronic component is sufficiently formed on the mounting land, so that the electronic component can be attached to the printed circuit board with sufficient mechanical strength. It is fixed with excellent strength, and the position where the electronic component is fixed is suppressed from moving on the melted solder during solder reflow and shifting from the original position where it was aligned and mounted. Accordingly, it is possible to provide a high-density mounting module having high mounting position accuracy.

FIG. 7 is a plan view showing another modification of the first embodiment. This other modification includes at least four lands 211, 212, 213, 214, and the minimum required four notches 221, 222, 223, 224 are They are distributed one by one in each area. In the case of an electronic component having four or more connection terminals, it is more preferable that the cutouts are distributed and arranged at positions spaced apart from each other.

<Second embodiment>
FIG. 8 is a plan view showing a second embodiment of the high-density mounting module of the present invention. In this further modification, the solder structure of the first embodiment shown in FIG. 1 is realized by an over-resist structure.

The module 101 includes a printed circuit board 105 having a first land 341, a second land 342, and a third land 343. The printed circuit board 105 has a first connecting terminal 151, a second connecting terminal 152, and a third connecting terminal connected to corresponding ones of the first land 341, the second land 342, and the third land 343. An electronic component 150 including a connection terminal 153 is mounted.

The surface of the printed circuit board 105 is covered with a solder resist. A first opening 311 that covers the peripheral edge of the first land 341 and is included in the area where the first land 341 is arranged is arranged in this solder resist. A first protrusion 321 that protrudes inward in one direction (X direction) is arranged. In addition, a second opening 312 is also arranged that covers the peripheral edge of the second land 342 and is included in the area where the second land 342 is arranged, and this second opening 312 has a first direction ( A third protrusion 323 is arranged to protrude inward in a second direction (Y direction) perpendicular to the X direction.

Further, a third opening 313 that covers the peripheral edge of the third land 343 and is included in the area where the third land 343 is arranged is arranged in this solder resist, and this third opening 313 has a , a second protrusion 322 protruding in a direction facing the first protrusion 321 in the first direction (X direction), and a direction facing the third protrusion 323 in the second direction (Y direction). A fourth protrusion 324 that protrudes from the top is disposed.

In this second embodiment, the first land 341, the second land 342, and the third land are exposed in the first opening 311, the second opening 312, and the third opening 313 of the solder resist. Cream solder can be selectively printed on the surface of each land 343 and solder reflow can be performed. At this time, cream solder is not formed on each of the inwardly protruding protrusions 321 to 324 of each of the openings 311 to 313.

Note that while the solder is melted in the reflow process, the solder melted on each land 341 to 343 flows only within the openings of the solder resist, so the planar shape of the solder after reflow is the same as that of each opening 311. It has the same planar shape as ~313. Therefore, in the second embodiment, it is possible to design the planar shape of the solder after reflow by making the shape of the opening in the solder resist a desired shape.

In the second embodiment, by using the same planar shape of the solder as in the first embodiment shown in FIG. 1, it is possible to restrict the movement of electronic components floating in the molten solder during solder reflow. Can be done. For example, when a force is generated to move the electronic component in the negative direction (X direction), the first protrusion 321 suppresses the movement of the first connection terminal 151 of the electronic component. Then, when a force to move the electronic component in the positive direction is generated, the second protrusion 322 suppresses the movement of the third connection terminal 153 of the electronic component.

Furthermore, when a force is generated to move the connection terminal 151 of the electronic component in the negative direction in the second direction (Y direction), the third protrusion 323 suppresses the movement of the connection terminal 151 of the electronic component, and the force to move it in the positive direction is suppressed. When this occurs, the second protrusion 322 can suppress the movement of the third connection terminal 153 of the electronic component, similarly to the first embodiment shown in FIG.

Therefore, even in an over-resist structure, by providing an inward protrusion in the opening of the solder resist and designing the planar shape of the solder, the same effect as when arranging a land with a notch can be obtained. can play.

As described above, according to the second embodiment, the solder fillet surrounding the connection terminal of the electronic component is sufficiently formed on the mounting land, so that the electronic component can be attached to the printed circuit board with sufficient mechanical strength. At the same time, the position where the electronic component is fixed is suppressed from shifting from the original position where it was aligned and mounted due to movement on the melted solder during solder reflow, and a good mounting position is achieved. A high-density mounting module with precision can be provided.

101 Module 105 Printed circuit board 111-113 First to third lands 121-126 First to sixth notches 150 Electronic components 151-153 First to third connection terminals 165 Solder fillet 301 Module 305 Printed circuit board 311- 313 First to third openings 321 to 324 First to fourth projections 341 to 343 First to third lands 351 to 353 First to third connection terminals 350 Electronic component X First direction Y Second direction of

Claims (6)

a printed circuit board having multiple lands;
A high-density mounting module comprising: an electronic component mounted on the printed circuit board and including a plurality of connection terminals connected to the plurality of lands;
The plurality of lands include a first land, a second land, and a third land on the printed circuit board, and the first land and the second land are arranged on a straight line extending in a first direction. The third land is adjacent to and spaced apart from the first land, and the third land is adjacent to the first land and the second land in a second direction perpendicular to the first direction. spaced apart from the land and the second land;
The plurality of lands include a first notch and a second notch extending in opposite directions in the first direction, and a third notch extending in opposite directions in the second direction. a notch and a fourth notch,
The first land has the first notch, the second land has the third notch, and the third land has the second notch and the fourth notch. have a defect,
In the vicinity of the tips of the first notch, the second notch, the third notch, and the fourth notch, the land protrudes laterally from the side surface of each of the plurality of connection terminals. In the portion where the amount of solder is small and the land protrudes laterally, a thin solder layer is formed on the surface thereof,
In a region where the first notch, the second notch, the third notch, and the fourth notch are formed, from each side of the plurality of connection terminals in the lateral direction of the land high-density mounting, in which a solder fillet is formed that has a large protrusion amount and extends from the side surface of each of the plurality of connection terminals of the electronic component to the surface of each land to which the connection terminals are connected; module. The high-density mounting module according to claim 1, wherein the plurality of lands further includes a fourth land where no notch is arranged. The high-density mounting module according to claim 1, wherein the plurality of lands include lands in which only one notch is arranged , that is, the first land and the second land . 4. The first cutout and the second cutout are each arranged on separate lands, and the separate lands are spaced apart from each other in the second direction. High-density mounting module described in . 5. The third notch and the fourth notch are each arranged on separate lands , and the separate lands are spaced apart from each other in the first direction. High-density mounting module described in . The plurality of lands further include a fifth notch extending in the first direction and a sixth notch extending in the second direction, according to any one of claims 1 to 5 . high-density mounting module.

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