JP2015179711A - Electronic part packaging method and electronic part packaging board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic part packaging method which makes difficult occurrence of a joint defect between an electronic part and a print board on an electronic part packaging board to be manufactured even when the electronic part to be packaged on the print board warps.SOLUTION: In an electronic part packaging method, solder paste 3 is first applied to a land electrode 21 provided on a print board 2. Next, a first reinforcing material 41 having a thermosetting property is coated in a first area R1 contained in a mount area Rm which an electronic part 1 will confront when the electronic part 1 is mounted on the print board 2. Here, the first area R1 is an area which is set within an area surrounded by the land electrode 21 at the outside and where the first reinforcing material 41 comes into contact with a part of the solder paste 3. The first reinforcing material 41 has a property that the hardening start temperature is higher than the melting point of the solder before coming into contact with the solder paste 3, and the hardening start temperature is lower than the melting point of the solder because of the contact with the solder paste 3.

Description

  The present invention relates to an electronic component mounting method and an electronic component mounting substrate, and more particularly to a mounting technology for an electronic component that has warped.

  In the mounting technology in which the soldering of the electronic component to the printed circuit board is performed through a reflow process, the electronic component of the ball grid array (BGA) type in which a plurality of bumps are arranged in a grid pattern as the electronic component mounted on the printed circuit board. Is often used (see, for example, Patent Document 1). In addition, in order to reduce the size and height of electronic component mounting boards, semiconductor components (for example, IC (Integrated Circuit) chips) that are bare chips on an interposer, which is a resin substrate, are mounted as electronic components on a printed circuit board. Bare chip-mounted products to which are mounted are often used.

  The interposer with a bare chip is usually warped at room temperature. Interposer warpage occurs as follows. That is, when a bare chip is attached to the interposer (for example, soldering or thermocompression bonding) in the process of manufacturing the bare chip attached product, the interposer expands by being heated and attached. Shrink in the cooling process after breaking. Here, the interposer is mainly made of resin, and the IC chip is mainly made of silicon (Si). For this reason, the thermal expansion coefficient of the interposer is usually larger than that of the bare chip. Therefore, when the interposer shrinks during the cooling process, the shrinkage amount of the chip mounting surface is opposite to the chip mounting surface due to the effect that the bare chip is fixed to the chip mounting surface of the interposer by solder bonding or adhesive. This is smaller than the shrinkage amount of the surface. Due to this difference in shrinkage, the interposer is warped so that the chip mounting surface becomes a convex surface.

JP 2008-300538 A

  As an electronic component mounted on a printed circuit board, particularly when a large-sized bare chip mounting product is used, the above-described warping of the interposer becomes significant. The bare chip mounting product that has caused such warping causes the following problems in the reflow process when mounted on a printed circuit board. That is, when the bare chip mounting product is heated in the reflow process, the interposer expands as the interposer temperature rises. At this time, the amount of expansion of the chip mounting surface is smaller than the amount of expansion of the surface opposite to the chip mounting surface due to the influence of the bare chip fixed to the chip mounting surface. Due to the difference in the expansion amount, the interposer is warped so that the chip mounting surface is concave. This warpage causes a bonding failure between the bare chip mounted product and the printed board. Specifically, it is difficult to form a preferable bonding state between a bump provided on the electronic component and a land electrode provided on the printed board.

  Accordingly, an object of the present invention is to provide an electronic component mounting board in which an electronic component that is less likely to cause a bonding failure between the electronic component and the printed board even if the electronic component mounted on the printed board is warped. A component mounting method and an electronic component mounting board manufactured by the mounting method are provided.

  A first electronic component mounting method according to the present invention includes an electronic component having a resin substrate having a main surface provided with a plurality of bumps, a plurality of land electrodes respectively corresponding to the plurality of bumps, and the electronic component is A method of mounting on a printed circuit board on which a land electrode is formed on a mounting surface, which includes steps (i) to (vi). Here, in the electronic component mounted on the printed board, warpage in which the main surface becomes a convex surface is generated on the resin substrate at room temperature. Further, the electronic component exhibits the following behavior as the temperature rises from room temperature. That is, the warp is relaxed by a rise in temperature from room temperature, and a warp in which the main surface becomes a concave surface is generated in the resin substrate by a further rise in temperature. In step (i), a solder paste is applied to the land electrode. In the step (ii), a first reinforcing material having thermosetting property is applied to a first area included in a mounting area where the resin substrate faces when an electronic component is mounted on the mounting surface. . Here, the first region is set in a region surrounded by the outer land electrode among the plurality of land electrodes, and the first reinforcing material is applied to a part of the solder paste applied in the step (i). Is the area that will come into contact. Further, the first reinforcing material has a property that the curing start temperature is higher than the melting point of the solder before the contact with the solder paste, and the curing start temperature becomes lower than the melting point of the solder by the contact with the solder paste. In step (iii), a second reinforcing material having the same properties as the first reinforcing material is applied to the second region included in the mounting region. Here, the second region is at least a part of the peripheral portion of the mounting region and is a region where the second reinforcing material does not come into contact with the solder paste applied in the step (i). In step (iv), the electronic component is mounted on the printed circuit board so that the bumps face the land electrodes corresponding to these bumps. After step (iv), in step (v), the electronic component and the printed circuit board at a first temperature that is equal to or higher than the curing start temperature of the first reinforcing material when it is in contact with the solder paste and lower than the melting point of the solder Are collectively heated, the second reinforcing material is not cured, and the warping of the resin substrate is eased and the first reinforcing material is cured. After the step (v), in the step (vi), the electronic component and the printed circuit board are collectively heated at a second temperature equal to or higher than the melting point of the solder, thereby melting the bumps and the first reinforcing material and the first reinforcing material. 2 Both the reinforcing materials are cured.

  A second electronic component mounting method according to the present invention includes an electronic component having a resin substrate having a main surface provided with a plurality of bumps, a plurality of land electrodes corresponding to the plurality of bumps, A method of mounting on a printed board in which land electrodes are formed on a mounting surface to be mounted, which includes steps (I) to (VI). Here, in the electronic component mounted on the printed board, warpage in which the main surface becomes a convex surface is generated on the resin substrate at room temperature. Further, the electronic component exhibits the following behavior as the temperature rises from room temperature. That is, the warp is relaxed by a rise in temperature from room temperature, and a warp in which the main surface becomes a concave surface is generated in the resin substrate by a further rise in temperature. In step (I), the solder paste is transferred to the bumps. In the step (II), a first reinforcing material having thermosetting property is applied to a first area included in a mounting area where the resin substrate faces when an electronic component is mounted on the mounting surface. . Here, the first region is set in a region surrounded by the outer land electrodes among the plurality of land electrodes, and is transferred in step (I) when the electronic component is mounted on the printed board. This is a region where the first reinforcing material comes into contact with a part of the solder paste. Further, the first reinforcing material has a property that the curing start temperature is higher than the melting point of the solder before the contact with the solder paste, and the curing start temperature becomes lower than the melting point of the solder by the contact with the solder paste. In step (III), a second reinforcing material having the same properties as the first reinforcing material is applied to the second region included in the mounting region. Here, the second region is at least a part of the peripheral portion of the mounting region, and when the electronic component is mounted on the printed circuit board, the second reinforcing material is applied to the solder paste transferred in the step (I). It is an area that does not come into contact. In step (IV), electronic components are mounted on the printed circuit board so that the bumps face the land electrodes corresponding to these bumps. After step (IV), in step (V), the electronic component and the printed circuit board at a first temperature that is equal to or higher than the curing start temperature of the first reinforcing material when it is in contact with the solder paste and lower than the melting point of the solder Are collectively heated, the second reinforcing material is not cured, and the warping of the resin substrate is eased and the first reinforcing material is cured. After step (V), in step (VI), the electronic component and the printed circuit board are heated together at a second temperature that is equal to or higher than the melting point of the solder, thereby melting the bumps, 2 Both the reinforcing materials are cured.

  An electronic component mounting board according to the present invention includes an electronic component having a resin substrate and a printed board having a plurality of land electrodes. In the printed circuit board, the land electrode is formed on a mounting surface on which an electronic component is mounted. Here, the electronic component is mounted on the printed circuit board with the main surface of the resin substrate opposed to the mounting surface. Each of the land electrodes is formed with a plurality of solder joints that join the land electrodes and the electronic component to each other in a state of being interposed between the mounting surface and the main surface. Of the mounting surface, the resin substrate is placed in a first region set in a region included in the mounting region where the resin substrate is opposed and surrounded by the outer land electrode among the plurality of land electrodes. A first resin reinforcing portion that is fixed to the printed circuit board and reinforces the bonding is formed in contact with at least one of the solder bonding portions. In addition, a second resin reinforcing portion that reinforces the bonding by fixing the resin substrate to the printed circuit board in the second region that is at least a part of the peripheral portion of the mounting region is formed in a non-contact state with the solder bonding portion. Has been.

  According to the electronic component mounting method of the present invention, even when the electronic component mounted on the printed board is warped, the electronic component mounted board to be manufactured is bonded between the electronic component and the printed board. Defects are less likely to occur. The electronic component mounting board according to the present invention is manufactured by such an electronic component mounting method.

It is a conceptual diagram of the electronic component mounted in a printed circuit board in the electronic component mounting method which concerns on 1st Embodiment of this invention. It is explanatory drawing of the printing process performed with the electronic component mounting method. It is explanatory drawing of the application | coating process performed with the electronic component mounting method. It is the top view which showed two examples regarding drawing application | coating of a 2nd reinforcement material. It is explanatory drawing of the transcription | transfer process performed with the electronic component mounting method. It is explanatory drawing of the mounting process performed with the electronic component mounting method. It is the figure which showed the temperature profile of the printed circuit board which passes the inside of a reflow furnace in the reflow process performed with the electronic component mounting method. It is explanatory drawing of the 1st heating process performed at a reflow process. It is a cutting part end view of the electronic component mounting board produced by the electronic component mounting method. It is explanatory drawing of the transcription | transfer process performed with the electronic component mounting method which concerns on 2nd Embodiment of this invention.

  The present inventors have found the following properties of a thermosetting resin (for example, epoxy resin) contained in a reinforcing material that reinforces the bonding of an electronic component to a printed circuit board. That is, when the thermosetting resin comes into contact with the solder paste, the curing start temperature higher than the melting point of the solder before the contact with the solder paste becomes lower than the melting point of the solder. And this invention is made | formed using the property of such a thermosetting resin.

First, an electronic component mounting method and an electronic component mounting board according to the present invention will be described.
A first electronic component mounting method according to the present invention includes an electronic component having a resin substrate having a main surface provided with a plurality of bumps, a plurality of land electrodes respectively corresponding to the plurality of bumps, and the electronic component is This is a method of mounting on a printed board in which land electrodes are formed on the mounting surface to be mounted. The first electronic component mounting method is particularly preferable when the resin substrate of the electronic component mounted on the printed circuit board is warped at room temperature with its main surface being a convex surface. An electronic component having such a warp includes a bare chip mounted product in which a bare chip is provided on the main surface and bumps are arranged around the bare chip. Further, the electronic component having the warp exhibits the following behavior as the temperature rises from room temperature. That is, the warpage of the resin substrate whose main surface is a convex surface is mitigated by a rise in temperature from room temperature, and the warpage of which the main surface is a concave surface is generated in the resin substrate by a further rise in temperature.

  Specifically, the first electronic component mounting method includes steps (i) to (vi). In step (i), a solder paste is applied to the land electrode. In the step (ii), a first reinforcing material having thermosetting property is applied to a first area included in a mounting area where the resin substrate faces when an electronic component is mounted on the mounting surface. . Here, the first region is set in a region surrounded by the outer land electrode among the plurality of land electrodes, and the first reinforcing material is applied to a part of the solder paste applied in the step (i). Is the area that will come into contact. Further, the first reinforcing material has a property that the curing start temperature is higher than the melting point of the solder before the contact with the solder paste, and the curing start temperature becomes lower than the melting point of the solder by the contact with the solder paste. In step (iii), a second reinforcing material having the same properties as the first reinforcing material is applied to the second region included in the mounting region. Here, the second region is at least a part of the peripheral portion of the mounting region and is a region where the second reinforcing material does not come into contact with the solder paste applied in the step (i). In step (iv), the electronic component is mounted on the printed circuit board so that the bumps face the land electrodes corresponding to these bumps. After step (iv), in step (v), the electronic component and the printed circuit board at a first temperature that is equal to or higher than the curing start temperature of the first reinforcing material when it is in contact with the solder paste and lower than the melting point of the solder Are collectively heated, the second reinforcing material is not cured, and the warping of the resin substrate is eased and the first reinforcing material is cured. After the step (v), in the step (vi), the electronic component and the printed circuit board are collectively heated at a second temperature equal to or higher than the melting point of the solder, thereby melting the bumps and the first reinforcing material and the first reinforcing material. 2 Both the reinforcing materials are cured.

  Step (i) corresponds to the printing step of the first embodiment described later, steps (ii) and (iii) correspond to the application step of the first embodiment described later, and step (iv) Corresponding to the mounting process of the first embodiment to be described later, processes (v) and (vi) correspond to the reflow process of the first embodiment to be described later.

  In the step (v), when the first reinforcing material starts to be cured, the viscosity and elastic modulus of the first reinforcing material are increased, and the bonding strength between the resin substrate and the printed circuit board via the first reinforcing material is increased. Become. On the other hand, when the heating temperature is increased in the step (vi), the resin substrate whose warpage has been relaxed in the step (v) further expands to cause a warp in which the main surface becomes a concave surface. However, since the bonding strength of the resin substrate and the printed circuit board through the first reinforcing material is increased, even when the heating temperature is increased in step (vi), the resin substrate is warped with the main surface being concave. However, it will be suppressed by the first reinforcing material.

  Further, since the second reinforcing material is not in contact with the solder paste, the curing start temperature of the second reinforcing material remains higher than the melting point of the solder. Accordingly, the curing of the second reinforcing material does not start in the step (v) in which the heating temperature is lower than the melting point of the solder, and the heating temperature in the step (vi) in which the heating temperature is equal to or higher than the melting point of the solder. It will start when the curing start temperature is reached. For this reason, at the time when melting of the solder starts in the step (vi), the second reinforcing material remains in a state of low viscosity and elastic modulus. Therefore, when the solder is melted, the bumps are sandwiched between the resin board and the printed circuit board due to the weight of the electronic component and deformed, so that a good bonding state between the electronic component and the printed circuit board is achieved. Will be obtained.

  On the other hand, if the second reinforcing material starts to cure at a heating temperature lower than the melting point of the solder, like the first reinforcing material, the viscosity and elastic modulus of the second reinforcing material are reduced before the solder is melted. Get higher. For this reason, even if the solder is melted in the step (vi), the deformation of the bump as described above is difficult to occur, and as a result, a good bonding state via the bump is provided between the electronic component and the printed board. It becomes difficult to obtain. Therefore, in order to obtain a good bonded state via the bumps, it is important to cause a difference in curing start temperature between the first reinforcing material and the second reinforcing material. In order to make such a difference, the method of bringing the first reinforcing material into contact with the solder paste is simple and particularly preferable.

  Therefore, according to the first electronic component mounting method, as a result of causing the difference in curing start temperature between the first reinforcing material and the second reinforcing material, the warping of the resin substrate that is likely to occur in the step (vi) is suppressed. In addition, a good bonding state via bumps can be obtained between the electronic component and the printed board. Therefore, it is difficult to cause a bonding failure between the electronic component and the printed board.

  In the step (ii), preferably, the first region is based on the land electrode that the bump will land when the electronic component is mounted on the printed board in the step (iv) among the plurality of land electrodes. The position is set near the land electrode.

  In order to exhibit the above properties of the first reinforcing material, the solder paste that contacts the first reinforcing material contains tin (Sn), the first reinforcing material contains an epoxy resin, and the solder paste and the first It is preferable that at least one of the reinforcing materials contains a carboxylic acid activator. This is because it is considered that tin and carboxylic acid have an action of lowering the curing start temperature of the epoxy resin. That is, when the solder paste and the first reinforcing material come into contact with each other, tin, the carboxylic acid-based activator, and the epoxy resin are mixed, and as a result, the hardening of the epoxy resin is started by the action of tin and the carboxylic acid. It is thought that the temperature decreases.

  In step (iii), the same reinforcing material as the first reinforcing material used in step (ii) is preferably used as the second reinforcing material. This makes it possible to perform the steps (ii) and (iii) at the same time with the same equipment. As a result, the process of applying the first reinforcing material and the second reinforcing material is simplified and the running cost is increased. Is reduced.

  The first electronic component mounting method preferably further includes a next step (vii) executed before the step (vi) in order to obtain a good bonding state via the bumps. That is, in step (vii), a bonding auxiliary material containing flux is transferred to bumps that land on the land electrode when an electronic component is mounted on a printed circuit board in step (iv) among the plurality of bumps. To do. The step (vii) corresponds to the transfer step of the first embodiment described later.

  A second electronic component mounting method according to the present invention includes an electronic component having a resin substrate having a main surface provided with a plurality of bumps, a plurality of land electrodes corresponding to the plurality of bumps, This is a method of mounting on a printed board in which land electrodes are formed on the mounting surface to be mounted. The second electronic component mounting method is particularly preferable when the resin substrate of the electronic component mounted on the printed circuit board is warped at room temperature with its main surface being a convex surface. An electronic component having such a warp includes a bare chip mounted product in which a bare chip is provided on the main surface and bumps are arranged around the bare chip. Further, the electronic component having the warp exhibits the following behavior as the temperature rises from room temperature. That is, the warpage of the resin substrate whose main surface is a convex surface is mitigated by a rise in temperature from room temperature, and the warpage of which the main surface is a concave surface is generated in the resin substrate by a further rise in temperature.

  Specifically, the second electronic component mounting method includes steps (I) to (VI). In step (I), the solder paste is transferred to the bumps. In the step (II), a first reinforcing material having thermosetting property is applied to a first area included in a mounting area where the resin substrate faces when an electronic component is mounted on the mounting surface. . Here, the first region is set in a region surrounded by the outer land electrodes among the plurality of land electrodes, and is transferred in step (I) when the electronic component is mounted on the printed board. This is a region where the first reinforcing material comes into contact with a part of the solder paste. Further, the first reinforcing material has a property that the curing start temperature is higher than the melting point of the solder before the contact with the solder paste, and the curing start temperature becomes lower than the melting point of the solder by the contact with the solder paste. In step (III), a second reinforcing material having the same properties as the first reinforcing material is applied to the second region included in the mounting region. Here, the second region is at least a part of the peripheral portion of the mounting region, and when the electronic component is mounted on the printed circuit board, the second reinforcing material is applied to the solder paste transferred in the step (I). It is an area that does not come into contact. In step (IV), electronic components are mounted on the printed circuit board so that the bumps face the land electrodes corresponding to these bumps. After step (IV), in step (V), the electronic component and the printed circuit board at a first temperature that is equal to or higher than the curing start temperature of the first reinforcing material when it is in contact with the solder paste and lower than the melting point of the solder Are collectively heated, the second reinforcing material is not cured, and the warping of the resin substrate is eased and the first reinforcing material is cured. After step (V), in step (VI), the electronic component and the printed circuit board are heated together at a second temperature that is equal to or higher than the melting point of the solder, thereby melting the bumps, 2 Both the reinforcing materials are cured.

  Step (I) corresponds to the transfer step of the second embodiment described later, steps (II) and (III) correspond to the application step of the second embodiment described later, and step (IV) Corresponding to the mounting process of the second embodiment to be described later, processes (V) and (VI) correspond to the reflow process of the second embodiment to be described later.

  According to the second electronic component mounting method, as in the first electronic component mounting method, a difference in curing start temperature occurs between the first reinforcing material and the second reinforcing material, and as a result, in step (VI) As a result, the warp of the resin substrate, which is likely to occur, is suppressed, and a good bonding state via the bumps is obtained between the electronic component and the printed board. Therefore, it is difficult to cause a bonding failure between the electronic component and the printed board.

  The electronic component mounting board according to the present invention is manufactured by the first or second electronic component mounting method. Here, each of the land electrodes is formed with a plurality of solder joint portions that join the land electrodes and the electronic component to each other in a state of being interposed between the mounting surface and the main surface. Of the mounting surface, the resin substrate is placed in a first region set in a region included in the mounting region where the resin substrate is opposed and surrounded by the outer land electrode among the plurality of land electrodes. A first resin reinforcing portion that is fixed to the printed circuit board and reinforces the bonding is formed in contact with at least one of the solder bonding portions. In addition, a second resin reinforcing portion that reinforces the bonding by fixing the resin substrate to the printed circuit board in the second region that is at least a part of the peripheral portion of the mounting region is formed in a non-contact state with the solder bonding portion. Has been.

  More specifically, the resin substrate has a slight warp whose main surface is a concave surface, and according to the warp, the height from the mounting surface of the solder joint that is in contact with the first resin reinforcing portion. However, it is larger than the height from the mounting surface about the solder joint part located in the vicinity of the 2nd resin reinforcement part.

Next, embodiments of the present invention will be specifically described with reference to the drawings.
[1] First Embodiment FIGS. 1A and 1B are respectively a cut-part end view and a bottom view of an electronic component mounted on a printed circuit board in the electronic component mounting method according to the first embodiment. FIG. 1A is an end view of the combined cut portion along the line ABCD-EFFGH shown in FIG. As shown in FIGS. 1A and 1B, the electronic component 1 has a rectangular interposer 11 that is a resin substrate, and an IC chip 12 that is mounted on the interposer 11 in a bare chip state. . The IC chip 12 is provided on the main surface 11a of the interposer 11, and a plurality of bumps 13 are further provided on the main surface 11a. In the present embodiment, the bumps 13 are arranged in a grid around the IC chip 12. That is, the electronic component 1 is a ball grid array (BGA) type bare chip mounting product. In the electronic component 1, a plurality of IC chips 12 that are not limited to one may be mounted on the main surface 11 a of the interposer 11.

  As a feature of the present embodiment, the interposer 11 of the electronic component 1 mounted on the printed circuit board is warped at a room temperature such that the main surface 11a provided with the bumps 13 is a convex surface. This warpage occurs in the process of manufacturing the electronic component 1. That is, when the IC chip 12 is attached (for example, soldering or thermocompression bonding) to the interposer 11, the interposer 11 is expanded by being heated, and a cooling process after the attachment is performed. Shrink at. Here, the interposer 11 is mainly made of resin, and the IC chip 12 is mainly made of silicon (Si). For this reason, the thermal expansion coefficient of the interposer 11 is usually larger than the thermal expansion coefficient of the IC chip 12. Therefore, when the interposer 11 contracts during the cooling process, the contraction amount of the main surface 11a is opposite to that of the main surface 11a due to the effect that the IC chip 12 is fixed to the main surface 11a by solder bonding or adhesive. It becomes smaller than the contraction amount of the side surface 11b. Due to the difference in contraction amount, the interposer 11 is warped so that the main surface 11a becomes a convex surface.

  The warp of the interposer 11 is quantified as follows, for example. That is, when the electronic component 1 is disposed with the bumps 13 facing downward as shown in FIG. 1A, these positions are the lowermost and uppermost positions of the main surface 11a that is warped in a convex shape. Is defined as an amount representing the warp of the interposer 11. In the present embodiment, the size of the interposer 11 is 18 mm × 30 mm × 0.82 mm (thickness), and the deviation width Δh is 50 μm or more and 800 μm or less.

  In the electronic component mounting method of the present embodiment, the printing process, the coating process, the transfer process, the mounting process, and the reflow process are executed in this order. The transfer process may be performed before the coating process or the printing process as long as it is before the mounting process, or may be performed in parallel with these processes.

  2A to 2C are explanatory diagrams of the printing process. Here, FIG. 2A is a plan view of the printed circuit board 2, and FIGS. 2B and 2C are A′-B′-C′-D′- shown in FIG. It is an end view of the combined cut part along the line E′-F′-G′-H ′. In the printing process, screen printing is performed on the printed circuit board 2. The printed circuit board 2 is supplied from a substrate supply device (not shown) such as a magazine type substrate loader. As shown in FIG. 2A, the printed circuit board 2 has a mounting surface 2a on which the electronic component 1 is mounted (mounted), and the interposer 11 is mounted on the mounting surface 2a when the electronic component 1 is mounted. A rectangular mounting region Rm that is to be opposed is provided. The printed circuit board 2 has a plurality of land electrodes 21 formed in the mounting region Rm. Each of these land electrodes 21 corresponds to a bump 13 provided on the electronic component 1 mounted in the mounting region Rm. The mounting surface 2a of the printed circuit board 2 may be provided with a plurality of mounting areas Rm that are not limited to one, and the electronic component 1 may be mounted in each mounting area Rm.

  In the printing process, as shown in FIGS. 2B and 2C, the screen printing using the screen 61 and the squeegee 62 is performed on the mounting surface 2a of the printed circuit board 2, whereby the solder paste is applied to each land electrode 21. 3 is given. The solder paste 3 contains solder as a main component and a carboxylic acid activator. The application of the solder paste 3 to the land electrode 21 is not limited to screen printing, and various printing methods such as ink jet printing can be used.

  3A and 3B are explanatory diagrams of the coating process. Here, FIG. 3A is a plan view of the printed circuit board 2, and FIG. 3B is A′-B′-C′-D′-E′-F shown in FIG. FIG. 3 is an end view of a combined cut portion taken along a line “-G” -H ”(the same line as the line shown in FIG. 2A). As shown in FIGS. 3A and 3B, in the coating process, the first reinforcing material 41 having thermosetting property is applied to the first region R1 (see FIG. 2A) included in the mounting region Rm. Apply. For the application of the first reinforcing material 41, an application device having an application nozzle 63 that discharges the first reinforcing material 41 is used. The discharge amount of the first reinforcing material 41 from the application nozzle 63 is adjusted by, for example, a dispenser provided in the application device.

  Specifically, the first region R1 is set in a region Rt surrounded by the outer land electrode 21 among the plurality of land electrodes 21, and a part of the solder paste 3 applied in the printing process. This is a region where the first reinforcing member 41 comes into contact. In the present embodiment, as shown in FIG. 3A, the first region R1 is 4 in the vicinity of the region Re that faces the IC chip 12 when the electronic component 1 is mounted in the mounting region Rm. The solder paste 3 applied to the land electrode 21 closest to the location and the first reinforcing material 41 are set to contact each other. And the 1st reinforcement material 41 is apply | coated to dot form with respect to 1st area | region R1. The first region R1 may be set in various regions within the region Rt that is not limited to the vicinity of the region Re. The application of the first reinforcing material 41 is not limited to the point application in which the first reinforcing material 41 is applied in the form of dots, but a drawing application in which the first reinforcing material 41 is applied in a linear shape may be used. Of course, the application of the first reinforcing material 41 may be a combination of dot application and drawing application.

  Preferably, the first region R1 is set according to the warp shape of the interposer 11. As an example, the first region R1 is formed when the electronic component 1 is mounted on the mounting region Rm in a mounting step (see FIG. 6B) described later among the plurality of land electrodes 21 formed in the mounting region Rm. With reference to the land electrode 21 on which the bump 13 will land, the position is set near the land electrode 21.

  The first reinforcing member 41 has a property that the curing start temperature Tc is higher than the melting point Tm of the solder before the contact with the solder paste 3, and the curing start temperature Tc becomes lower than the melting point Tm of the solder by the contact with the solder paste 3. have. Here, the melting point Tm of the solder is the melting point of the solder contained in the solder paste 3 or the solder contained in the bump 13. Specifically, the first reinforcing material 41 includes a thermosetting resin having such properties as a main component. For example, an epoxy resin is used as the thermosetting resin. The above properties of the first reinforcing member 41 are explained as follows. The metal (mainly tin (Sn)) contained in the solder in the solder paste 3 and the carboxylic acid in the solder paste 3 generate a carboxylic acid metal salt by heating. When the first reinforcing material 41 is in contact with the solder paste 3, the epoxy group is ring-opened by the addition reaction of the carboxylic acid metal salt to the epoxy group contained in the epoxy resin (thermosetting resin). A group is generated. This hydroxyl group causes a polymerization reaction at a lower temperature than the epoxy group. For this reason, the curing start temperature Tc of the first reinforcing material 41 is lowered by the contact of the first reinforcing material 41 with the solder paste 3.

  In order to exhibit the above properties of the first reinforcing material 41, it is important that a metal carboxylate is generated in addition to the contact of the first reinforcing material 41 with the solder paste 3. And this carboxylic acid metal salt is produced | generated by a metal and carboxylic acid as mentioned above. In this embodiment, the carboxylic acid activator is included in the solder paste 3, but may be included in the first reinforcing material 41 instead. Of course, the carboxylic acid activator may be contained in both the solder paste 3 and the first reinforcing material 41.

  In the applying step, a second reinforcing material 42 having the same properties as the first reinforcing material 41 is further applied to the second region R2 (see FIG. 2A) included in the mounting region Rm. In the application process of the present embodiment, the same reinforcing material as the first reinforcing material 41 is used as the second reinforcing material 42. By using the same material for the first reinforcing material 41 and the second reinforcing material 42, it becomes possible to execute the application of the first reinforcing material 41 and the application of the second reinforcing material 42 in a lump in the same facility, As a result, the coating process is simplified and the running cost is reduced.

  Specifically, the second region R2 is at least a part of the peripheral portion of the mounting region Rm, and the second reinforcing material 42 is not in contact with the solder paste 3 applied in the printing process. . In the present embodiment, as shown in FIG. 3A, the second region R2 is in contact with the solder paste 3 applied to the land electrode 21 at each of the four corners present in the rectangular mounting region Rm. It is set so that there is nothing. And the 2nd reinforcement material 42 is apply | coated to dot shape with respect to 2nd area | region R2. Note that the second region R2 may be set in various regions within the peripheral edge that are not limited to the corners of the mounting region Rm. However, the second region R2 is set so that the second reinforcing material 42 does not come into contact with the solder paste 3. Further, the application of the second reinforcing material 42 is not limited to the point application in which the second reinforcing material 42 is applied in the form of dots, but a drawing application in which the second reinforcing material 42 is applied in a linear form may be used. As an example, the second reinforcing member 42 may be applied in an L shape along the peripheral edge of the mounting region Rm as shown in FIG. 4A, or the mounting region as shown in FIG. 4B. It may be applied in a U shape along the peripheral edge of Rm. Of course, the application of the second reinforcing material 42 may be a combination of dot application and drawing application.

  5A to 5D are explanatory diagrams of the transfer process. As shown in FIGS. 5A to 5D, in the transfer process, the bonding auxiliary material 5 containing the flux is transferred to the bumps 13 provided on the electronic component 1. The joining auxiliary material 5 may contain solder or a carboxylic acid activator. For transferring the joining auxiliary material 5, an auxiliary material supply device having a tray-type transfer stage 64, a squeegee 65, and a scraper 66 is used. In this auxiliary material supply device, a gap for forming the auxiliary material coating film 51 is provided between the cutting edge of the squeegee 65 and the transfer stage 64. The dimension of the gap is adjusted according to the viscosity of the auxiliary bonding material 5 and the thickness of the auxiliary material coating film 51 to be formed. The scraper 66 is in surface contact with the transfer stage 64 so that the joining auxiliary material 5 on the transfer stage 64 can be scraped.

  In the transfer step, first, as shown in FIG. 5A, the joining auxiliary material 5 is injected between the squeegee 65 and the scraper 66. Thereafter, as shown in FIG. 5B, the auxiliary material coating 51 is formed on the surface of the transfer stage 64 by moving the squeegee 65 and the scraper 66 in the horizontal direction D1 along the surface of the transfer stage 64. To do.

  Next, the electronic component 1 is attracted to the tip of the suction nozzle 67 of the mounting device so that the bumps 13 face downward. And after moving the electronic component 1 to the upper direction of the auxiliary material coating film 51, it is dropped in the state which faced the bump 13 below. As a result, the bump 13 is landed on the auxiliary material coating film 51 as shown in FIG. As described above, the interposer 11 of the electronic component 1 is warped such that the main surface 11a is a convex surface. Therefore, when the electronic component 1 is lowered, among the plurality of bumps 13 provided on the main surface 11a, the electronic component 1 is mainly landed on the land electrode 21 when the electronic component 1 is mounted on the mounting region Rm. The bump 13 is landed on the auxiliary material coating film 51.

  Thereafter, as shown in FIG. 5D, the bump 13 is separated from the auxiliary material coating film 51 by pulling up the electronic component 1. In this way, the bonding auxiliary material 5 is transferred to the bumps 13. As a result, among the plurality of bumps 13 provided on the main surface 11a, the bonding auxiliary material 5 is applied to the bumps 13 that land on the land electrode 21 when the electronic component 1 is mounted in the mounting region Rm. It will be transcribed. In the transfer process, the bonding auxiliary material 5 is transferred not only to the bumps 13 that land on the land electrodes 21 during mounting but also to the bumps 13 that are separated from the land electrodes 21 during mounting due to warpage of the interposer 11. May be.

  After the transfer of the bonding auxiliary material 5 to the bump 13, the squeegee 65 and the scraper 66 are moved in a direction D2 opposite to the direction D1, thereby scraping the bonding auxiliary material 5 on the transfer stage 64 (FIG. 5 (a). )reference). Then, by moving the squeegee 65 and the scraper 66 in the direction D1 again, the auxiliary material coating film 51 used for the next transfer is prepared (see FIG. 5B).

  6A and 6B are explanatory diagrams of the mounting process. In the mounting process, first, as shown in FIG. 6A, the electronic component 1 is conveyed above the mounting region Rm provided on the printed circuit board 2 while being attracted to the tip of the suction nozzle 67. At this time, the electronic component 1 is disposed above the mounting region Rm so that the bumps 13 provided on the electronic component 1 face the land electrodes 21 corresponding thereto. Next, as shown in FIG. 6B, the electronic component 1 is mounted on the mounting region Rm by lowering the electronic component 1.

  In the reflow process, the printed circuit board 2 on which the electronic component 1 is mounted is passed through the reflow furnace. FIG. 7 is a view showing a temperature profile of the printed circuit board 2 passing through the reflow furnace. As shown in FIG. 7, in the reflow process, the first heating process, the second heating process, and the cooling process are performed in this order.

  FIG. 8 is an explanatory diagram of the first heating step. The first heating step is a step of preheating the printed circuit board 2. In the first heating step, the electronic component 1 and the printed circuit board 2 are heated together at a first temperature T1 suitable for the preheating. To do. Here, the first temperature T1 is equal to or higher than the curing start temperature Tc of the first reinforcing member 41 when in contact with the solder paste 3 and lower than the melting point Tm of the solder. Preferably, the first temperature T1 is a temperature of 150 ° C. or higher and 180 ° C. or lower.

  According to the first heating step, it is possible to alleviate the warp of the interposer 11 and start the curing of the first reinforcing material 41 as shown in FIG. 8 without causing the second reinforcing material 42 to be cured. The warping of the interposer 11 occurs during the process of expansion of the interposer 11 due to preheating. Specifically, when the interposer 11 is expanded, the expansion amount of the main surface 11a is opposite to the main surface 11a due to the influence that the IC chip 12 is fixed to the main surface 11a by solder bonding, adhesive, or the like. It becomes smaller than the expansion amount of the surface 11b. This difference in the expansion amount reduces the warp of the interposer 11. Then, all the bumps 13 provided on the main surface 11a land on the land electrodes 21 corresponding to the bumps 13 by the relaxation of the warp. Moreover, when the hardening of the 1st reinforcement material 41 starts, the viscosity and elastic modulus of the 1st reinforcement material 41 increase, and the joint strength via the 1st reinforcement material 41 of the interposer 11 and the printed circuit board 2 increases. Become.

  In the second heating step, the electronic component 1 and the printed circuit board 2 are heated together at a second temperature T2 that is equal to or higher than the melting point Tm of the solder. Preferably, the second temperature T2 is a temperature of 220 ° C. or higher and 260 ° C. or lower. Moreover, it is preferable that the peak temperature in a 2nd heating process is the temperature of 240 degreeC or more and 260 degrees C or less. According to the second heating step, the solder contained in the bumps 13 and the solder paste 3 is melted.

  When the heating temperature is increased in the second heating step, the interposer 11 whose warpage has been relaxed in the first heating step is further expanded to cause a warp in which the main surface 11a becomes a concave surface. On the other hand, before the heating temperature is increased (before the second heating step is performed), the first reinforcing member 41 is cured in the first heating step, and the first interposer 11 and the printed circuit board 2 are first cured. The bonding strength through the reinforcing material 41 is increased. For this reason, even when the heating temperature is increased in the second heating step, the first reinforcing member 41 suppresses the occurrence of warpage of the interposer 11 in which the main surface 11a is a concave surface.

  Since the second reinforcing material 42 is not in contact with the solder paste 3, the curing start temperature Tc of the second reinforcing material 42 remains higher than the melting point Tm of the solder. Accordingly, the curing of the second reinforcing material 42 does not start in the first heating process in which the heating temperature is lower than the melting point Tm of the solder, and in the second heating process in which the heating temperature is equal to or higher than the melting point Tm of the solder, the heating temperature is the second. It starts when the curing start temperature Tc of the reinforcing material 42 is reached. For this reason, at the time when melting of the solder is started in the second heating step, the second reinforcing material 42 remains in a state of low viscosity and elastic modulus. Therefore, when the solder is melted, the bump 13 is deformed by being sandwiched between the interposer 11 and the printed circuit board 2 by the weight of the electronic component 1, and thus the bump 13 is formed between the electronic component 1 and the printed circuit board 2. Therefore, a good joined state can be obtained.

  On the other hand, if the second reinforcing material 42 starts hardening at a heating temperature lower than the melting point Tm of the solder, like the first reinforcing material 41, the viscosity of the second reinforcing material 42 before the melting of the solder. And the elastic modulus becomes high. For this reason, even if the solder is melted in the second heating process, the deformation of the bumps 13 as described above is difficult to occur, and as a result, the bumps 13 are interposed between the electronic component 1 and the printed circuit board 2. It becomes difficult to obtain a proper joined state. Therefore, in order to obtain a good bonding state via the bumps 13, it is important to cause a difference in the curing start temperature Tc between the first reinforcing material 41 and the second reinforcing material 42 as in this embodiment. is there. In order to make such a difference, the method of bringing the first reinforcing material 41 into contact with the solder paste 3 is simple and particularly preferable.

  Further, when the melting of the solder starts, the viscosity and elastic modulus of the first reinforcing material 41 are higher than the viscosity and elastic modulus of the second reinforcing material 42. In the second heating step, the interposer 11 tends to cause a warp in which the main surface 11 a becomes a concave surface, while the warp is suppressed by the first reinforcing material 41. Therefore, when the bump 13 is deformed by the weight of the electronic component 1, the interposer 11 is only slightly warped so that the main surface 11a becomes a concave surface (see FIG. 9).

  Thereafter, the curing of the first reinforcing material 41 proceeds and the curing of the second reinforcing material 42 starts. As a result, both the first reinforcing material 41 and the second reinforcing material 42 are cured in the second heating step. When the 1st reinforcement material 41 and the 2nd reinforcement material 42 harden | cure, the 1st resin reinforcement part 71 and the 2nd resin reinforcement part 72 which are these hardened | cured materials are formed, respectively (refer FIG. 9). The 1st resin reinforcement part 71 and the 2nd resin reinforcement part 72 adhere the interposer 11 to the printed circuit board 2, and reinforce these joining.

  In the cooling process, the electronic component 1 and the printed circuit board 2 are cooled to solidify the melted solder. As a result, each bump 13 and the corresponding solder paste 3 on the land electrode 21 are integrated, and as a result, a plurality of solder joint portions 73 that join the land electrode 21 and the electronic component 1 to each other are mounted. It is formed in a state of being interposed between the surface 2a and the main surface 11a (see FIG. 9).

  In the cooling process, the interposer 11 contracts as the temperature of the interposer 11 decreases. At this time, the interposer 11 is unlikely to warp such that the main surface 11a becomes a convex surface. However, this warpage is suppressed by the second resin reinforcing portion 72 that has been cured, and the interposer 11 is maintained in a state in which the main surface 11a is slightly warped with a concave surface. As a result, the electronic component mounting board shown in FIG. 9 is completed.

  In the manufactured electronic component mounting substrate, the first resin reinforcing portion 71 exists in a state in contact with at least one of the solder joint portions 73, and the second resin reinforcing portion 72 is in a non-contact state with the solder joint portion 73. Exists. Further, as a result of shifting the timing of the start of curing by the first reinforcing material 41 and the second reinforcing material 42, the warp of the interposer 11 in which the main surface 11a is a concave surface is suppressed. That is, the interposer 11 is only slightly warped so that the main surface 11a becomes a concave surface. Then, according to the warp, the height h1 from the mounting surface 2a of the solder joint portion 73 in contact with the first resin reinforcement portion 71 is about the solder joint portion 73 located in the vicinity of the second resin reinforcement portion 72. It is larger than the height h2 from the mounting surface 2a.

  As the height h1 is larger than the height h2, a bonding failure is likely to occur in the solder joint portion 73 in contact with the first resin reinforcing portion 71. Therefore, as described above, the bonding auxiliary material 5 is applied to the corresponding bumps 13 in the transfer process of the present embodiment. As a result, it is possible to prevent occurrence of poor bonding at the solder joint portion 73 in contact with the first resin reinforcing portion 71. From the viewpoint of preventing the occurrence of such poor bonding, it is preferable that solder is included in the bonding auxiliary material 5.

  According to the electronic component mounting method according to the first embodiment, the warp of the interposer 11 that is likely to occur in the reflow process as a result of causing a difference in the curing start temperature Tc between the first reinforcing member 41 and the second reinforcing member 42. Is suppressed, and a good bonding state via the bumps 13 is obtained between the electronic component 1 and the printed circuit board 2. Therefore, it is difficult for a bonding failure to occur between the electronic component 1 and the printed circuit board 2.

[2] Second Embodiment In the first embodiment, instead of applying the solder paste 3 to each land electrode 21 in the printing process, the solder paste 3 may be transferred to the bumps 13 in the transfer process. Good. This aspect will be specifically described below as a second embodiment. Note that the mounting process and the reflow process executed in the second embodiment are the same as those in the first embodiment, and a description thereof will be omitted.

  10A to 10D are explanatory diagrams of a transfer process executed in the present embodiment. As shown in FIGS. 10A to 10D, in the transfer process of the present embodiment, solder paste 3 is used instead of the bonding auxiliary material 5 and solder is applied to all the bumps 13 provided on the electronic component 1. The paste 3 is transferred. The solder paste 3 contains solder as a main component and a carboxylic acid activator.

  In the transfer step, first, the solder paste 3 is injected between the squeegee 65 and the scraper 66 as shown in FIG. Thereafter, as shown in FIG. 10B, the squeegee 65 and the scraper 66 are moved in the horizontal direction D1 along the surface of the transfer stage 64 to form the solder paste coating film 31 on the surface of the transfer stage 64. To do.

  Next, the electronic component 1 is attracted to the tip of the suction nozzle 67 of the mounting device so that the bumps 13 face downward. Then, after the electronic component 1 is moved above the solder paste coating 31, the bump 13 is lowered with the bump 13 facing downward. As a result, as shown in FIG. 10C, all the bumps 13 provided on the electronic component 1 are landed on the solder paste coating 31. Here, as described above, the interposer 11 of the electronic component 1 is warped so that the main surface 11a becomes a convex surface. Therefore, the solder paste coating film 31 is preferably formed to have a thickness that allows all the bumps 31 to land on the solder paste coating film 31. Alternatively, the warp of the interposer 11 is temporarily corrected by pressing the bump 13 against the transfer stage 64 and adjusting the load applied to the electronic component 1 in order to land all the bumps 13 on the solder paste coating 31. May be.

  Thereafter, as shown in FIG. 10 (d), the bump 13 is separated from the solder paste coating 31 by pulling up the electronic component 1. In this way, the solder paste 3 is transferred to all the bumps 13 provided on the main surface 11a.

  In the application step, the first reinforcing material 41 having thermosetting property is applied to the first region R1 included in the mounting region Rm, and the same as the first reinforcing material 41 is applied to the second region R2 included in the mounting region Rm. A second reinforcing material 42 having properties is applied (see FIGS. 2A, 3A, and 3B). In the application process of the present embodiment, the same reinforcing material as the first reinforcing material 41 is used as the second reinforcing material 42.

  Here, since the printing process is not executed in this embodiment, the solder paste 3 is not applied to the land electrode 21. Accordingly, the first region R1 is set in the region Rt surrounded by the outer land electrode 21 among the plurality of land electrodes 21, and the transfer process is performed when the electronic component 1 is mounted on the mounting region Rm. This is a region where the first reinforcing material 41 comes into contact with a part of the solder paste 3 transferred in step (b). The second region R2 is at least a part of the peripheral portion of the mounting region Rm, and the second reinforcement is applied to the solder paste 3 transferred in the transfer process when the electronic component 1 is mounted on the mounting region Rm. This is a region where the material 42 does not come into contact.

  According to the electronic component mounting method according to the second embodiment, the difference in curing start temperature Tc occurs between the first reinforcing material 41 and the second reinforcing material 42 as in the first embodiment, and as a result, the reflow process is performed. As a result, the warp of the interposer 11 that is likely to occur is suppressed, and a good bonding state via the bumps 13 is obtained between the electronic component 1 and the printed board 2. Therefore, it is difficult for a bonding failure to occur between the electronic component 1 and the printed circuit board 2.

  In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. For example, the present invention includes an electronic component mounting method that does not include a transfer process in the first embodiment. Moreover, each part structure of the said embodiment is applicable not only when mounting a bare chip mounting product on a printed circuit board but when mounting various electronic components which produced the curvature on a printed circuit board.

  The electronic component mounting method according to the present invention can be applied to the manufacture of an electronic component mounting substrate (for example, a microprocessor) provided in an electronic device such as a computer.

1 Electronic component 11 Interposer (resin substrate)
11a Main surface 12 IC chip (bare chip)
13 Bump 2 Printed circuit board 2a Mounting surface 21 Land electrode 3 Solder paste 31 Solder paste coating 41 First reinforcing material 42 Second reinforcing material 5 Joining auxiliary material 51 Auxiliary material coating 61 Screen 62 Squeegee 63 Application nozzle 64 Transfer stage 65 Squeegee 66 Scraper 67 Suction nozzle 71 First resin reinforcing part 72 Second resin reinforcing part 73 Solder joints D1, D2 direction h1, h2 Height Rm Mounting area R1 First area R2 Second area Rt area Re area T1 First temperature T2 Second temperature Tc Curing start temperature Tm Solder melting point Δh Deviation width

Claims (10)

It has a resin substrate having a main surface provided with a plurality of bumps, and the warp in which the main surface becomes a convex surface occurs in the resin substrate at room temperature, and the warp is mitigated by a rise in temperature from the room temperature, An electronic component in which a warp in which the main surface becomes a concave surface due to a further rise in temperature occurs in the resin substrate has a plurality of land electrodes corresponding to the plurality of bumps, and the mounting surface on which the electronic component is mounted A method of mounting on a printed circuit board on which the land electrode is formed,
(I) applying a solder paste to the land electrode;
(Ii) Applying a first reinforcing material having thermosetting property to a first region included in a mounting region of the mounting surface where the resin substrate faces when the electronic component is mounted. The first region is set in a region surrounded by an outer land electrode among the plurality of land electrodes, and one of the solder pastes applied in the step (i). The first reinforcing material is in contact with the solder paste, and the first reinforcing material has a curing start temperature higher than the melting point of the solder before the contact with the solder paste, and the contact with the solder paste. The curing start temperature is lower than the melting point of the solder, the process,
(Iii) a step of applying a second reinforcing material having the same properties as the first reinforcing material to the second region included in the mounting region, wherein the second region is a peripheral portion of the mounting region; A step which is at least a part and is a region where the second reinforcing material does not come into contact with the solder paste applied in the step (i);
(Iv) mounting the electronic component on the printed circuit board so that the bumps respectively face the land electrodes corresponding to the bumps;
(V) After the step (iv), at a first temperature that is equal to or higher than the curing start temperature of the first reinforcing material when in contact with the solder paste and lower than the melting point of the solder, Heating the printed circuit board in a lump to reduce the warp of the resin substrate without causing the curing of the second reinforcing material, and starting the curing of the first reinforcing material;
(Vi) After the step (v), the bumps are melted by heating the electronic component and the printed circuit board together at a second temperature equal to or higher than the melting point of the solder, and the first reinforcement is performed. A method of mounting both the material and the second reinforcing material.   In the step (ii), the first region is a land electrode from which the bumps land when the electronic component is mounted on the printed board in the step (iv) among the plurality of land electrodes. The electronic component mounting method according to claim 1, wherein the electronic component mounting method is set at a position near the land electrode with reference to.   The electronic component mounting method according to claim 1, wherein the solder paste contains a carboxylic acid activator.   The electronic component mounting method according to claim 1, wherein the first reinforcing material and the second reinforcing material contain a carboxylic acid activator.   The electronic component according to claim 1, wherein in the step (iii), the same reinforcing material as the first reinforcing material used in the step (ii) is used as the second reinforcing material. Implementation method. (Vii) Before the step (iv), among the plurality of bumps, the bump that will land on the land electrode when the electronic component is mounted on the printed board in the step (iv), The electronic component mounting method according to any one of claims 1 to 5, further comprising a step of transferring a joining auxiliary material containing flux.   The electronic component mounting method according to claim 1, wherein the electronic component further includes a bare chip provided on the main surface, and the bumps are arranged around the bare chip. It has a resin substrate having a main surface provided with a plurality of bumps, and the warp in which the main surface becomes a convex surface occurs in the resin substrate at room temperature, and the warp is mitigated by a rise in temperature from the room temperature, An electronic component in which a warp in which the main surface becomes a concave surface due to a further rise in temperature occurs in the resin substrate has a plurality of land electrodes corresponding to the plurality of bumps, and the mounting surface on which the electronic component is mounted A method of mounting on a printed circuit board on which the land electrode is formed,
(I) a step of transferring a solder paste to the bump;
(II) A first reinforcing material having thermosetting property is applied to a first area included in a mounting area on which the resin substrate faces when the electronic component is mounted on the mounting surface. The first region is set in a region surrounded by an outer land electrode among the plurality of land electrodes, and when the electronic component is mounted on the printed circuit board, It is a region where the first reinforcing material comes into contact with a part of the solder paste transferred in the step (I), and the first reinforcing material has a curing start temperature before contact with the solder paste. Having a property that the melting start temperature is lower than the melting point of the solder due to contact with the solder paste, the melting point being higher than the melting point of the solder;
(III) A step of applying a second reinforcing material having the same property as the first reinforcing material to a second region included in the mounting region, wherein the second region is a peripheral portion of the mounting region. The second reinforcing material is a region that is at least a part and does not come into contact with the solder paste transferred in the step (I) when the electronic component is mounted on the printed board. Process,
(IV) mounting the electronic component on the printed circuit board so that the bumps respectively face the land electrodes corresponding to the bumps;
(V) After the step (IV), at a first temperature that is equal to or higher than the curing start temperature of the first reinforcing material when being in contact with the solder paste and lower than the melting point of the solder, Heating the printed circuit board in a lump to reduce the warp of the resin substrate without causing the curing of the second reinforcing material, and starting the curing of the first reinforcing material;
(VI) After the step (V), the electronic component and the printed circuit board are collectively heated at a second temperature equal to or higher than the melting point of the solder, thereby melting the bumps and the first reinforcement. A method of mounting both the material and the second reinforcing material. An electronic component having a resin substrate;
A printed circuit board having a plurality of land electrodes, wherein the land electrodes are formed on a mounting surface on which the electronic component is mounted;
The electronic component is mounted on the printed circuit board with the main surface of the resin substrate facing the mounting surface,
Each of the land electrodes is formed with a plurality of solder joints that join the land electrodes and the electronic component to each other in a state of being interposed between the mounting surface and the main surface,
Of the mounting surface, a region included in the mounting region opposed to the resin substrate, the first region set in a region surrounded by an outer land electrode of the plurality of land electrodes, A first resin reinforcing portion for fixing the resin substrate to the printed circuit board to reinforce the bonding is formed in contact with at least one of the solder bonding portions;
A state in which the second resin reinforcing portion for fixing the resin substrate to the printed circuit board and reinforcing the bonding to the second region which is at least a part of the peripheral portion of the mounting region is in non-contact with the solder joint portion An electronic component mounting board formed of   The resin substrate has a slight warp with the main surface being a concave surface, and the height from the mounting surface of the solder joint portion in contact with the first resin reinforcing portion is increased according to the warp. The electronic component mounting substrate according to claim 9, wherein the solder joint portion located in the vicinity of the second resin reinforcing portion is larger than a height from the mounting surface.

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