JP2015050355A - Electrical part mounting method and electrical part mounting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrical part mounting method that can be automated on an electrical part mounting line and produce a three-dimensional electrical part mounting structure reinforced by resin with high productivity.SOLUTION: An electrical part mounting method comprises: (i) a step of preparing a board having a first mounting area; (ii-1) a step of mounting, on the first mounting area of the board, a first electrical part having plural bumps on one principal surface and a second mounting area on the other principal surface; (iii-1) a step of mounting a second electrical part larger in outer shape than the first electrical part on the second mounting area of the first electrical part mounted on the first mounting area; and (iv) a step of coating reinforcing resin on the board so as to come into contact with the peripheral edge portion of the second electrical part before the step (iii-1). In the step (iii-1), the reinforcing resin is spread out by the peripheral edge of the second electrical part, whereby the reinforcing resin is pressed against the peripheral edge portion of the first electrical part.

Description

  The present invention relates to an electronic component mounting method and an electronic component mounting structure, and more particularly to a three-dimensional mounting technique for stacking and mounting a plurality of electronic components on a substrate.

  Various electronic components (packages) are incorporated in an electronic device. In particular, in mobile devices such as mobile phones and portable music players that require high-density mounting, a plurality of packages are stacked and mounted on a substrate. Three-dimensional mounting has become an essential technology. According to the three-dimensional mounting, for example, a structure in which an application processor and a memory used by the application processor are stacked and arranged can be easily realized. This saves space on the printed circuit board and shortens the signal path. Therefore, it becomes easy to improve the performance of the electronic device and reduce power consumption.

  Among three-dimensional packaging, package-on-package (hereinafter abbreviated as PoP) is only a good package compared to other three-dimensional packaging technologies such as through-silicon via (TSV). Since the layers can be freely selected and stacked, the yield can be easily improved. Therefore, it is easy to reduce the manufacturing cost (see Patent Document 1).

  Currently, most of the packages used for PoP are BGA (Ball grid array) packages with some special exceptions. In the mounting process of surface mount components (SMD) such as BGA packages, solder paste is generally printed onto land electrodes on a board by a screen printer, and the board is carried into a chip mounter. The In the chip mounter, the SMD is mounted on the substrate so that the solder bumps of the BGA package are landed on the land electrodes from the printed solder paste.

  The substrate on which the SMD is mounted is carried into a reflow furnace, and the solder paste and solder bumps are heated there, whereby the SMD electrode and the substrate electrode are soldered together. Inside the chip mounter, the chip mounting head picks up the SMD from the supply device, recognizes its posture, and mounts it on the substrate.

  When an electronic component mounting structure composed of a substrate and an electronic component obtained by the SMD mounting process as described above is subjected to thermal stress due to a heat cycle or an impact due to dropping of a device, the solder joint is damaged, A faulty connection may occur. Therefore, for example, an electronic component is fixed to a substrate with a reinforcing portion including a thermosetting resin (reinforcing resin) to reinforce the solder joint portion. As a method of reinforcing the solder joint portion with such a reinforcement portion, a method of reinforcing the solder joint portion by bonding only the peripheral edge portion of the electronic component to the substrate is currently the mainstream (see Patent Documents 2 and 3). .

JP 2012-235170 A JP 2008-300538 A JP 2010-272557 A

  In general, when a solder joint is reinforced with a reinforcing resin, the reinforcing resin is applied to a reinforcing portion on a peripheral portion (for example, a corner portion) of the electronic component before the electronic component is soldered to the substrate by a reflow process. . Thereby, a solder joining process and the thermosetting process of the reinforcing resin can be performed simultaneously in a later reflow process. Therefore, it is easy to automatically reinforce the solder joint using an electronic component mounting line having a general apparatus configuration.

  However, in PoP, not only the lowermost package (hereinafter also referred to as the bottom package) is fixed to the substrate, but the upper package (for example, the top package) is also fixed to the upper surface of the bottom package or the substrate surface. There is a need. However, it is not easy to form a reinforcing portion for fixing the upper package to the substrate surface. Therefore, for example, it is necessary to apply such a reinforcing resin to the substrate manually to form such a reinforcing portion.

  Accordingly, an object of the present invention is to provide an electronic component mounting method and an electronic component mounting structure capable of easily forming a reinforcing portion for fixing an upper layer package of PoP to a substrate surface.

One aspect of the present invention is: (i) preparing a substrate having a first mounting area;
(Ii-1) mounting a first electronic component having a plurality of bumps on one main surface and a second mounting region on the other main surface in the first mounting region of the substrate;
(Iii-1) mounting a second electronic component having an outer shape larger than that of the first electronic component on the second mounting region of the first electronic component mounted on the first mounting region;
(Iv) before the step (iii-1), a step of applying a reinforcing resin to the substrate so as to be in contact with the peripheral edge of the second electronic component;
In the step (iii-1), the electronic component mounting method is configured to press the reinforcing resin against the peripheral portion of the first electronic component by spreading the reinforcing resin with the peripheral portion of the second electronic component. .

Another aspect of the present invention is: (i) preparing a substrate having a first mounting area;
(Ii-2) A step of stacking and mounting a plurality of first electronic components having a plurality of bumps on one main surface and a second mounting region on the other main surface in the first mounting region of the substrate. When,
(Iii-2) Out of the plurality of first electronic components stacked and mounted in the first mounting region, the outer shape of the first electronic component in the uppermost stage is more external than the first electronic component. Mounting a second electronic component having a large size;
(Iv) before the step (iii-2), applying a reinforcing resin to the substrate so as to be in contact with the peripheral edge of the second electronic component;
In the step (iii-2), an electronic component mounting that presses the reinforcing resin against the peripheral portions of the plurality of first electronic components by spreading the reinforcing resin with the peripheral portions of the second electronic component Regarding the method.

Still another aspect of the present invention provides a substrate having a first mounting region;
A first electronic component mounted on the first mounting area and having a plurality of bumps on one main surface and a second mounting area on the other main surface;
A second electronic component mounted in the second mounting area and having a larger outer shape than the first electronic component;
The present invention relates to an electronic component mounting structure including a resin reinforcing portion that contacts a peripheral portion of the first electronic component and also contacts a peripheral portion of the second electronic component.

  At this time, a plurality of the first electronic components are stacked and mounted on the first mounting region, and the second electronic component is mounted on the second mounting region of the uppermost first electronic component. It is also preferable.

  The electronic component mounting method of the present invention can be automated on an electronic component mounting line, and a three-dimensional electronic component mounting structure reinforced with resin can be manufactured with high productivity.

It is a partial cross section figure of an example of the board | substrate used for the electronic component mounting method which concerns on Embodiment 1 of this invention. It is the partial sectional view which looked at an example of the 1st electronic component used for the electronic component mounting method from the front. It is the partial sectional view which looked at an example of the 2nd electronic component used for the electronic component mounting method from the front. It is explanatory drawing of the procedure of the same electronic component mounting method, Comprising: The state (a) with which the solder paste was printed on the board | substrate, the application process (b) of reinforcement resin, the mounting process (c) of a 1st electronic component, 2nd It is explanatory drawing which shows the state (e) which the mounting process (d) of an electronic component, the solder joining process, and the reinforcement part formation process were complete | finished. It is a partial cross section figure of the electronic component mounting structure manufactured by the modification of the electronic component mounting method concerning Embodiment 1 of this invention. It is a top view which shows schematic structure of the chip mounter used at the mounting process of a 1st electronic component and a 2nd electronic component, and the application | coating process of reinforcement resin. It is a top view of the board | substrate with which resin for reinforcement was apply | coated to four reinforcement positions. It is a figure which illustrates the application pattern of resin for reinforcement. It is a top view of the board | substrate with which the resin for reinforcement was apply | coated to the four reinforcement positions based on Embodiment 2 of this invention, and the 3rd electronic component was mounted.

  One aspect of the present invention includes (i) a step of preparing a substrate having a first mounting area, and (ii-1) a first mounting area of the substrate having a plurality of bumps on one main surface and the other main Mounting a first electronic component having a second mounting area on the surface, and (iii-1) mounting a second electronic component on the second mounting area of the first electronic component mounted on the first mounting area; , And an electronic component mounting method. In this method, instead of the step (ii-1), the step (ii-2), that is, the first mounting region of the substrate has a plurality of bumps on one main surface and the second main surface has a second. A step of stacking and mounting a plurality of first electronic components having mounting areas may be executed. Further, instead of the step (iii-1), the step (iii-2), that is, the first electronic component of the uppermost stage among the plurality of first electronic components stacked and mounted in the first mounting region. The step of mounting the second electronic component having a larger outer shape than the first electronic component in the two mounting areas may be executed.

  Typically, the present invention is an on-board stack type in which a plurality of electronic components (packages) are mounted so as to be sequentially stacked on a substrate, and the electronic components are joined to the substrate in a batch by reflow. The present invention relates to package on package (hereinafter referred to as PoP). Here, the outer shape of the second electronic component is larger than that of the first electronic component. As a result, when the second electronic component is stacked on the first electronic component and the electronic component is viewed along the direction perpendicular to the surface of the substrate, at least a part of the peripheral portion of the second electronic component is the first electronic component. 1 It protrudes outside the outer shape of the electronic component.

  Here, the area of the second electronic component (the projected area of the outer shape on the substrate) can be set to 1.2 to 2 times the area of the first electronic component. Or the minimum distance LM (refer FIG.4 (e)) of the outline of the external shape of a 1st electronic component and the outline of the outline of the 2nd electronic component which protrudes on the outer side is the range of 0.5-5 mm It is also preferable to make it inside.

  The electronic component mounting method of the present invention further includes a step of applying a reinforcing resin to the substrate so as to come into contact with the peripheral portion of the second electronic component before the step (iii-1) or (iii-2). (Iv) At this time, the reinforcing resin may be applied before mounting the first electronic component on the first mounting region of the substrate, or may be applied after mounting. Further, the reinforcing resin may be applied so as to contact the peripheral edge of the first electronic component, or may be applied so as not to contact.

  And in the electronic component mounting method of this invention, when mounting a 2nd electronic component in a 2nd mounting area | region in process (iii-1) or (iii-2), it is a board | substrate by the peripheral part of a 2nd electronic component. By spreading the reinforcing resin applied to the resin, the reinforcing resin is pressed against the peripheral edge of the first electronic component. Thereby, for example, the reinforcing resin can be brought into contact with the peripheral portions of both the first electronic component and the second electronic component only by performing a single application step of the reinforcing resin before the reflow step. Therefore, the first electronic component and the second electronic component can be fixed to the substrate with high strength in a later reflow process. Therefore, a three-dimensional mounting structure with good impact resistance can be manufactured with high productivity.

  Solder paste can be printed on each land electrode in the first mounting region of the substrate by, for example, screen printing before mounting the first electronic component. Further, before the first electronic component is mounted on the first mounting region, the flux can be supplied to each of the plurality of bumps, for example, by transfer. Either one or both of the solder paste printing and the flux transfer can be performed.

  In one form of the mounting method of the present invention, in step (iv), the reinforcing resin is applied to the substrate so as not to contact the first electronic component. By applying the reinforcing resin in this manner, for example, when the reinforcing resin is applied to the substrate after the first electronic component is mounted on the substrate, the resin application nozzle (hereinafter referred to as an application nozzle) is applied to the first electronic component. ) Can be easily applied without contact. Therefore, it becomes easy to increase the application speed of the reinforcing resin, and it becomes easy to improve productivity. Further, when the first electronic component is mounted on the substrate after the reinforcing resin is applied to the substrate, it is easy to mount the first electronic component without contacting the resin. Thereby, it becomes possible to prevent the shape of the resin from collapsing, and it is possible to prevent the reinforcing strength from being lowered. Further, it becomes easy to increase the mounting speed of the first electronic component, and it becomes easy to improve productivity.

  In one form of the mounting method of the present invention, the substrate has a third mounting region for mounting the third electronic component. Here, at least a part of the third mounting region faces the peripheral edge of the second electronic component. In this case, a step of mounting the third electronic component in the third mounting region is performed before the step (iii-1) or (iii-2). However, the height of the third electronic component is smaller than the distance between the substrate and the peripheral edge of the second electronic component.

  The third electronic component is a small electronic component, typically a chip-type electronic component. In the mounting method of the present embodiment, such a small electronic component is mounted on the lower side of the peripheral portion of the second electronic component protruding outside the first electronic component (see FIG. 9). This makes it possible to effectively use the space on the substrate surface, and prevents the space efficiency on the substrate surface from being reduced by making the outer shape of the second electronic component larger than the outer shape of the first electronic component. be able to.

  Another aspect of the present invention includes a substrate having a first mounting area, a plurality of bumps on one main surface mounted on the first mounting area, and a second mounting area on the other main surface. The present invention relates to an electronic component mounting structure having a first electronic component and a second electronic component mounted in a second mounting area and having a larger outer shape than the first electronic component. Here, the electronic component mounting structure of the present invention has a resin reinforcing portion that contacts the peripheral portion of the first electronic component and also contacts the peripheral portion of the second electronic component.

  That is, the electronic component mounting structure of the present invention is a structure manufactured by the above electronic component mounting method. As an external feature, the outer shape of the second electronic component is larger than the outer shape of the first electronic component. On the other hand, in PoP, conventionally, two or more packages having the same outer shape are stacked. This is because the space efficiency of the substrate surface and the space efficiency of each electronic component can both be maximized.

  In the electronic component mounting structure of the present invention, the reinforcing resin previously applied to the substrate surface is spread by the peripheral edge of the uppermost electronic component (second electronic component), and is applied to the peripheral edge of the first electronic component. It is pressed. And the peripheral part of the 1st electronic component and the 2nd electronic component is each directly fixed to the board | substrate by the integral resin reinforcement part which consists of resin for reinforcement.

  In one form of the electronic component mounting structure of the present invention, the substrate has a third mounting region for mounting the third electronic component, and at least a part of the third mounting region is a peripheral edge of the second electronic component. It faces the part. The third electronic component is mounted in the third mounting area. However, the height of the third electronic component is smaller than the distance between the substrate and the peripheral edge of the second electronic component.

Embodiments of the present invention will be specifically described below with reference to the drawings.
(Embodiment 1)
FIG. 1 is a partial cross-sectional view showing an example of a substrate used in the electronic component mounting method according to the present embodiment. FIG. 2 shows an example of the first electronic component in a partial cross-sectional view as seen from the front. FIG. 3 shows an example of the second electronic component as a partial cross-sectional view as seen from the front.

  The substrate 100 in the illustrated example has a first mounting area AR1 on which the first electronic component 200 is mounted on one main surface. A plurality of land electrodes 102 are provided in the first mounting area AR1. The land electrodes 102 are regularly arranged in a matrix, for example. On one main surface (first main surface) 201 </ b> A of the first electronic component 200, a plurality of terminals are provided corresponding to the arrangement of the land electrodes 102. Each terminal is provided with a bump 202. On the other main surface (second main surface) 201B of the first electronic component 200, there is a second mounting area AR2 on which the second electronic component 500 is mounted. The outer shape of the second electronic component 500 is larger than the outer shape of the first electronic component 200.

  For example, the area of the second electronic component (the projected area of the outer shape on the substrate) can be about 20 to 100% larger than the area of the first electronic component. Or the minimum distance LM (refer FIG.4 (e)) of the outline of the external shape of a 1st electronic component and the outline of the outline of the 2nd electronic component which protrudes on the outer side is the range of 0.5-5 mm It is also preferable to make it inside.

  The first mounting area AR1 is an area on the substrate having the same outer shape as that of the first electronic component 200 mounted on the substrate. That is, the outline of the projection shape of the first electronic component 200 when the first electronic component 200 mounted on the substrate is viewed along the direction perpendicular to the surface of the substrate is the boundary line of the first mounting area AR1. . The boundary line of the second mounting area AR2 can also be defined on the surface of the substrate 100 in the same manner as the boundary line of the first mounting area AR1. Since the outer shape of the second electronic component 500 is larger than the outer shape of the first electronic component 200, in the illustrated example, the entire second main surface 201B of the first electronic component 200 is the second mounting area AR2.

  As the first electronic component 200, a ball grid array (BGA) package including a semiconductor element such as a processor IC can be used. On the other hand, as the second electronic component 500, a BGA package including a semiconductor element such as a memory IC can be used. When the second electronic component 500 is a BGA package, the second electronic component 500 also has a plurality of bumps 502. At this time, the terminal electrodes 204 corresponding to the respective bumps 502 can be provided in the second mounting area AR2 of the first electronic component 200.

  Next, the electronic component mounting method according to the present embodiment will be described with reference to FIG. First, the substrate 100 is prepared. Next, as necessary, the solder paste 104 is printed on each land electrode 102 of the substrate 100 by, for example, screen printing (see FIG. 4A).

  Next, the reinforcing resin 402 is applied to the resin installation region ARP set on the main surface of the substrate 100 where the first mounting region AR1 is present, for example, by a dispenser (see FIG. 4B). In the illustrated example, the reinforcing resin 402 is applied to the resin installation region ARP by the application nozzle 312a attached to the dispenser.

  In the resin installation area ARP, when the second electronic component 500 is mounted on the second mounting area AR2 of the first electronic component 200 mounted on the first mounting area AR1, the peripheral portion 500a of the second electronic component 500 is reinforced. It is set at a position in contact with the resin 402 for use. At this time, the height LH of the reinforcing resin 402 applied to the substrate is larger than the distance L1 between the lower surface of the second electronic component 500 and the substrate surface (see FIG. 4D). Resin 402 is applied.

  Further, the resin installation area ARP can be provided outside the first mounting area AR1 so as to be adjacent to the first mounting area AR1. Alternatively, the resin installation area ARP can be provided so as to at least partially overlap the first mounting area AR1. In the example shown in FIG. 4B, the resin installation area ARP is adjacent to the first mounting area AR1 with a predetermined interval LS (see FIG. 4C) outside the first mounting area AR1. Is provided. A preferable range of the interval LS is 0.1 to 1.5 mm. By providing such an interval LS, it becomes easy to mount the first electronic component 200 without contacting the reinforcing resin 402 in the subsequent first electronic component mounting step.

  On the other hand, when a part of the resin installation area ARP overlaps the first mounting area AR1, when the first electronic component 200 is mounted in the first mounting area AR1, the first electronic component 200 becomes the reinforcing resin 402. May come into contact with In order to facilitate the mounting process of the first electronic component 200 and increase the productivity, it is preferable to dispose the resin installation area ARP outside the first mounting area AR1. The reinforcing resin 402 may contain an activator for removing the oxide films of the bumps 202 and 502 and the land electrode 102. Thereby, even when the reinforcing resin 402 adheres to bumps or the like, it is possible to prevent the formation of the solder joints from being hindered. Further details of the resin installation area ARP will be described later.

  Next, the first electronic component 200 is mounted on the first mounting area AR1 of the substrate 100 using, for example, a chip mounter (see FIG. 4C). In the illustrated example, the first electronic component 200 sucked by the suction nozzle 311a of the electronic component mounting head is mounted in the first mounting area AR1. In the mounting process of the first electronic component 200, it is preferable that the flux is attached to the bump 202 when the first electronic component 200 is mounted on the first mounting area AR1.

  A method of attaching the flux to the bump 202 is not particularly limited, but a method of transferring a flux coating film formed on a flat surface using a squeegee to the bump 202 is preferable. However, when the solder paste is printed on the land electrode 102, the necessity to transfer the flux to the bump 202 is small. Accordingly, only one of the solder paste printing on the land electrode 102 and the flux transfer on the bump 202 can be performed.

  Next, for example, by using the same chip mounter as the above chip mounter, the second electronic component 500 is further laminated on the first electronic component 200 mounted on the substrate. The second electronic component 500 is mounted on the second mounting area AR2 (see FIG. 4D). Thereby, the reinforcing resin 402 is pushed and spread by the peripheral edge portion 500 a of the second electronic component 500. As a result, the reinforcing resin 402 is pressed against the peripheral edge of the first electronic component 200. By performing the above steps, the reinforcing resin 402 supplied onto the substrate by a single coating step can be reliably brought into contact with the peripheral portions of both the first electronic component 200 and the second electronic component 500. .

  Also in the mounting process of the second electronic component 500 (see FIG. 4D), when the second electronic component 500 is mounted on the second mounting area AR2, the flux 408 is attached to the bump 502 by, for example, transfer. be able to.

  Next, the board | substrate 100 with which the 1st electronic component 200 and the 2nd electronic component 500 were laminated | stacked and mounted is carried in, for example to a reflow furnace, and a reflow process is performed. As a result, as shown in FIG. 4E, the solder joint portions 412 and 414 are formed, and the reinforcing resin 402 is thermoset to form the resin reinforcing portion 416. Thus, the electronic component mounting structure 600 is completed.

  As described above, the second electronic component 500 whose outer shape is larger than that of the first electronic component 200 is mounted so as to be stacked on the first electronic component 200 from above the first electronic component 200. As a result, the reinforcing resin 402 previously applied on the substrate can be pushed and spread by the peripheral edge portion 500a of the second electronic component 500 protruding outside the outer shape of the first electronic component 200. Thereby, the reinforcing resin 402 can be pressed against the peripheral edge of the first electronic component 200. Therefore, the reinforcing resin 402 is securely brought into contact with the peripheral portions of both the first electronic component 200 and the second electronic component 500, and the first electronic component 200 and the second electronic component 500 are integrated by the integral resin reinforcing portion 416. It can be bonded and fixed to the substrate.

  In addition, by applying the reinforcing resin to the substrate before the reflow process, the application area of the reinforcing resin can be made smaller than when applying the resin after the reflow process. As shown in FIG. 4, the application nozzle 312a is usually used vertically downward. When the reinforcing resin is applied after the reflow process, the application nozzle 312a is disposed at least outside the outer shape of the second electronic component, and the reinforcing resin is hidden under the second electronic component. It is necessary to continue the discharge until the peripheral edge is reliably contacted. For this reason, it is necessary to apply many reinforcing resins compared to the case where the reinforcing resin is applied before the reflow process. As a result, the application area becomes large. According to the electronic component mounting method of the present embodiment, the application area of the reinforcing resin can be reduced, so that it is easy to secure a space for mounting other electronic components on the substrate surface. Thereby, an electronic component can be mounted on a substrate with higher density.

  In the method shown in FIG. 4, only two electronic components, the first electronic component 200 and the second electronic component 500, are stacked on the substrate. The present invention is not limited to this case, and can also be applied to a case where three or more electronic components are stacked and mounted on a substrate. In this case, as shown in FIG. 5, the uppermost electronic component of the electronic component mounting structure 600A is the second electronic component 500, and the outer shape thereof is the outer shape of any other first electronic component in the lower layer. Larger than. The outer shapes of the two or more first electronic components below the second electronic component are preferably made equal to each other. Thereby, the reinforcing resin 402 can be reliably pressed against the peripheral edge of two or more electronic components in the lower layer. Of the two or more first electronic components, the second electronic component is mounted in the second mounting region of the uppermost first electronic component 200A. Other first electronic components (for example, the first electronic component 200A) are mounted in the second mounting region of the other first electronic components 200.

  In the method shown in FIG. 4, after the step of applying the reinforcing resin 402 (see FIG. 4B) is executed, the step of mounting the first electronic component 200 (see FIG. 4C) is executed. Yes. In the present invention, the present invention is not limited to this. After the first electronic component 200 is mounted on the first mounting area AR1, the reinforcing resin 402 is applied to the substrate, and then the steps shown in FIG. May be. After the first electronic component 200 is mounted on the first mounting area AR1, the time from the application of the resin to the mounting of the second electronic component can be shortened by applying the reinforcing resin 402 to the substrate. . Therefore, the reinforcing resin 402 can be easily applied to the substrate so as to have a height that should be in contact with the peripheral portion of the second electronic component 500 without particularly increasing the viscosity of the reinforcing resin 402.

  FIG. 6 is a view of the internal structure of the chip mounter for mounting the first electronic component and the second electronic component on the substrate as viewed from above. The chip mounter 303 in the illustrated example includes a first component supply unit 307 that supplies the first electronic component 200, a second component supply unit 308 that supplies the second electronic component 500, and a substrate holding unit that holds and positions the substrate 100. 309, a transfer device 310 for supplying a coating film of flux, and a base 303a on which these are arranged.

  The chip mounter 303 further includes a movable mounting head 311 for mounting the supplied first electronic component 200 and the second electronic component 500 on the substrate 100, and a movable for supplying a thermosetting resin as the reinforcing resin 402. A coating head 312, a mounting head 311, and a control unit 313 that controls movement and operation of the coating head 312 are provided. The mounting head 311 and the coating head 312 are supported by a dedicated XY movement mechanism (not shown), and move in the upper space of the base 303a under the control of the XY movement mechanism by the control unit 313.

  The structures of the first component supply unit 307 and the second component supply unit 308 are not particularly limited. For example, a tray on which a plurality of first electronic components 200 arranged in a grid pattern is placed is picked up by the mounting head 311. A tray feeder is provided.

  The substrate holding unit 309 that holds and positions the substrate 100 may have any structure. For example, as illustrated in FIG. 6, the substrate holding unit 309 includes a substrate transport conveyor 315 that transports a carrier 314 that holds the substrate 100. The substrate transport conveyor 315 functions as a substrate holding unit 309 in order to transport and position the substrate 100 to a position where each electronic component is mounted.

  The mounting head 311 includes a suction nozzle 311a that moves up and down by a built-in lifting mechanism. The first electronic component 200 and the second electronic component 500 are picked up from the first component supply unit 307 and the second component supply unit 308 by the lifting operation and suction of the suction nozzle 311a. Further, the electronic component is mounted on the substrate 100 by a lifting operation and a suction release (vacuum break) at a predetermined position of the substrate 100.

  A movable coating head 312 for supplying a thermosetting resin as the reinforcing resin 402 incorporates a dispenser having a coating nozzle 312a for discharging the reinforcing resin 402 and a lifting mechanism for moving the coating nozzle 312a up and down. . The coating head 312 may be supported by a dedicated XY movement mechanism and move in the space above the base 303a. The coating head 312 is integrated with the mounting head 311 and the base is moved by a common XY movement mechanism. It is good also as a structure which moves the upper space of 303a.

  Operations such as movement of the mounting head 311 and pickup and mounting of electronic components by the mounting head 311 are controlled by commands from the control unit 313. Similarly, operations such as movement of the coating head 312 and ejection of the reinforcing resin 402 from the coating head 312 are controlled by commands from the control unit 313. The control unit 313 includes a memory 313a that stores a program for restricting movement and operation of the mounting head 311 and the coating head 312, a central processing unit 313b such as a CPU or MPU, various interfaces, and a personal computer.

  Usually, a plurality of resin installation areas ARP are set in an area corresponding to the peripheral edge portion 500a of the second electronic component 500 on the substrate. Here, the region corresponding to the peripheral portion 500 a of the second electronic component 500 of the substrate 100 is a frame-shaped region set on the substrate along the outer shape of the second electronic component 500. The resin installation area ARP is set at a predetermined location in the frame-shaped area. In addition, the resin installation area | region ARP does not necessarily need to be stored in the range of the peripheral part 500a.

  When the coating head 312 has a small-diameter coating nozzle 312a as shown in FIG. 4B, the reinforcing resin 402 is supplied from the coating nozzle 312a to the resin installation area ARP in a linear or dotted manner. It is preferable to do. At this time, productivity is improved by adjusting the amount of the reinforcing resin 402 to be supplied so as not to be too large. Further, defects such as protrusion of the reinforcing resin 402 are suppressed.

  The shape of the peripheral part of a general BGA type electronic component is rectangular. In a rectangular electronic component, it is preferable to apply a reinforcing resin to a plurality of resin installation areas ARP corresponding to at least four corners of the peripheral edge of the rectangle or the vicinity thereof. By setting the resin installation area ARP in such an arrangement, a large reinforcing effect can be obtained even when a small amount of reinforcing resin is used. Further, since the balance of reinforcement is good, it is easy to reduce the stress generated in the solder joint when the first or second electronic component receives an impact.

Next, the application pattern of the reinforcing resin 402 will be specifically described.
FIG. 7 is a plan view of the substrate 100 when the reinforcing resin 402 is applied to the four resin placement regions ARP corresponding to the four corners of the peripheral edge portion 500a of the rectangular second electronic component 500. FIG.

  FIG. 8 exemplifies five types of reinforcing resin coating patterns. In the four-point application pattern (a), the eight-point application pattern (b), and the L-type application pattern (d), a plurality of resins are installed outside the four corners of the outer shape of the rectangular first electronic component 100 or in the vicinity thereof. Area ARP is set. In the 12-point application pattern (c), the resin installation area ARP is also set outside the intermediate portion of each side of the outer shape of the first electronic component 100. Also in the U-type coating pattern (e), the resin installation area ARP is set so as to include the four corners and the vicinity thereof. The reinforcing effect increases in the order of the application patterns (a) to (e), but the application time becomes longer and the amount of the reinforcing resin used also increases. On the other hand, repair (reworkability) is improved in the order of the application patterns (e) to (a). The application pattern may be appropriately selected in consideration of the reinforcing effect according to the size of the electronic component and the production tact.

  In addition, you may apply | coat reinforcement resin to substantially the whole peripheral part. However, since gas may be generated from the reinforcing resin or flux during the reflow of the bump, it is desirable to provide an opening for releasing the gas.

Next, the reinforcing resin will be described.
A thermosetting resin is used as the reinforcing resin. Examples of the thermosetting resin include an epoxy resin, a phenol resin, a melamine resin, and a urethane resin. The thermosetting resin may contain a curing agent, a curing accelerator, and the like. As the curing agent, an acid anhydride, an aliphatic or aromatic amine, imidazole or a derivative thereof is preferably used, and examples of the curing accelerator include dicyandiamide.

  The reinforcing resin may contain a component having an action of removing an oxide present on the surface of the land electrode, the component electrode, or the bump. For example, an activator included in the flux may be included in the reinforcing resin. Thereby, even when the reinforcing resin comes into contact with the land electrode or the bump, wetting of the melted bump and the electrode is more reliably ensured.

(Embodiment 2)
Next, Embodiment 2 of the present invention will be described. FIG. 9 is a plan view showing a state in which the reinforcing resin is applied to the substrate used in the electronic component mounting method according to the present embodiment and the third electronic component is mounted in the third mounting region. The illustrated substrate 100A has a third mounting area AR3 on which small third electronic components 601 and 602 such as chip-type electronic components are mounted. At least a part of the third mounting area AR3 faces the peripheral edge 500a of the second electronic component 500. The third mounting area AR3 may all face the peripheral edge 500a of the second electronic component 500. The heights of the third electronic components 601 and 602 are smaller than the distance L1 (see FIG. 4D) between the substrate 100 and the peripheral portion 500a of the second electronic component 500.

  The mounting of the third electronic component is performed after a step of printing a solder paste on the land electrode 102 of the substrate 100 (see FIG. 4A). The third electronic component is mounted at least before the second electronic component 500 is mounted in the second mounting area AR2. Other configurations of the electronic component mounting method of the present embodiment are the same as those of the first embodiment.

  As described above, by providing the mounting area for the third electronic components 601 and 602 at a position overlapping the peripheral edge 500a of the second electronic component 500, the outer shape of the second electronic component 500 is larger than the outer shape of the first electronic component. As a result, it is possible to prevent the space efficiency on the substrate surface from decreasing. Thereby, it becomes easy to manufacture an electronic component mounting structure having high impact resistance and high mounting density of electronic components.

  According to the present invention, it is possible to achieve high connection reliability and high productivity in a package-on-package in which a plurality of electronic components are stacked and mounted on a substrate. This is useful in the field of surface mounting of BGA type electronic components.

  DESCRIPTION OF SYMBOLS 100,100A ... Board | substrate, 102 ... Land electrode, 104 ... Solder paste, 201A ... 1st main surface, 201B ... 2nd main surface, 202 ... Bump, 204 ... Terminal electrode, 303 ... Chip mounter, 303a ... Base, 307 ... first component supply unit, 308 ... second component supply unit, 309 ... substrate holding unit, 310 ... transfer device, 311 ... mounting head, 311a ... suction nozzle, 312 ... application head, 312a ... application nozzle, 313 ... control unit 313a, memory, 313b, central processing unit, 314, carrier, 315, substrate conveyor, 402, resin for reinforcement, 408, flux, 412, 414, joint, 416, resin reinforcement, 500, second electronic component , 500a ... peripheral edge, 502 ... bump, 600 ... electronic component mounting structure, 601, 602 ... third electronic component, L1 ... spacing, AR ... first mounting region, AR2 ... second mounting region, AR3 ... third mounting area

Claims (9)

(I) preparing a substrate having a first mounting area;
(Ii-1) mounting a first electronic component having a plurality of bumps on one main surface and a second mounting region on the other main surface in the first mounting region of the substrate;
(Iii-1) mounting a second electronic component having an outer shape larger than that of the first electronic component on the second mounting region of the first electronic component mounted on the first mounting region;
(Iv) before the step (iii-1), a step of applying a reinforcing resin to the substrate so as to be in contact with the peripheral edge of the second electronic component;
In the step (iii-1), an electronic component mounting method in which the reinforcing resin is pressed against the peripheral portion of the first electronic component by spreading the reinforcing resin by the peripheral portion of the second electronic component.   The electronic component mounting method according to claim 1, wherein, in the step (iv), the reinforcing resin is applied to the substrate so as not to contact the first electronic component. The substrate has a third mounting region, and at least a part of the third mounting region faces the peripheral edge of the second electronic component;
Before the step (iii-1), further comprising a step of mounting a third electronic component on the third mounting region;
3. The electronic component mounting method according to claim 1, wherein a height of the third electronic component is smaller than a distance between the substrate and the peripheral portion of the second electronic component. (I) preparing a substrate having a first mounting area;
(Ii-2) A step of stacking and mounting a plurality of first electronic components having a plurality of bumps on one main surface and a second mounting region on the other main surface in the first mounting region of the substrate. When,
(Iii-2) Out of the plurality of first electronic components stacked and mounted in the first mounting region, the outer shape of the first electronic component in the uppermost stage is more external than the first electronic component. Mounting a second electronic component having a large size;
(Iv) before the step (iii-2), applying a reinforcing resin to the substrate so as to be in contact with the peripheral edge of the second electronic component;
In the step (iii-2), an electronic component mounting that presses the reinforcing resin against the peripheral portions of the plurality of first electronic components by spreading the reinforcing resin with the peripheral portions of the second electronic component Method.   The electronic component mounting method according to claim 4, wherein in the step (iv), the reinforcing resin is applied to the substrate so as not to contact the plurality of first electronic components. The substrate has a third mounting region, and at least a part of the third mounting region faces the peripheral edge of the second electronic component;
Before the step (iii-2), further comprising a step of mounting a third electronic component on the third mounting region;
6. The electronic component mounting method according to claim 4, wherein a height of the third electronic component is smaller than a distance between the substrate and the peripheral portion of the second electronic component. A substrate having a first mounting area;
A first electronic component mounted on the first mounting area and having a plurality of bumps on one main surface and a second mounting area on the other main surface;
A second electronic component mounted in the second mounting area and having a larger outer shape than the first electronic component;
An electronic component mounting structure comprising: a resin reinforcing portion that contacts a peripheral portion of the first electronic component and also contacts a peripheral portion of the second electronic component. The substrate has a third mounting region, and at least a part of the third mounting region faces the peripheral edge of the second electronic component;
A third electronic component is mounted on the third mounting region;
The electronic component mounting structure according to claim 7, wherein a height of the third electronic component is smaller than a distance between the substrate and the peripheral portion of the second electronic component.   The plurality of first electronic components are stacked and mounted on the first mounting region, and the second electronic component is mounted on the second mounting region of the uppermost first electronic component. The electronic component mounting structure according to 7 or 8.

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