Surface mounting techniques using inserters
By generating a void array on the sheet and forming an inserter with an adhesive layer, the problem of welding balls being prone to break under mechanical and thermal stress is solved, and the effect of enhancing the strength of the welded joint and improving the reliability of electronic components is achieved.
Patent Information
- Application Number
- CN202380015584.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-25
- Publication Date
- 2025-05-27
AI Technical Summary
The solder balls connecting the substrate and components are prone to break when subjected to mechanical and thermal stress, causing the entire device to fail.
An array of voids is generated on the sheet and an inserter is formed through the first and second adhesive layers, attached to the components and substrates, followed by reflow soldering at a temperature above the melting point of the solder balls, curing the adhesive layer to form a bottom filler.
By forming the underfill, the strength of the welded joint is enhanced, the risk of breaking under mechanical and thermal stress is avoided, and the reliability of electronic components is improved.
Smart Images
Figure CN120052062A_ABST
Abstract
Description
Background Art
[0001] Surface Mount Technology (SMT) is a technology used to manufacture electronic components, where components are directly mounted onto the surface of a substrate such as a Printed Circuit Board (PCB). For the vast majority of electronic devices, components are specifically designed to be directly mounted onto the substrate rather than hard-wired to it. SMT allows for increased manufacturing automation, thereby reducing costs and improving quality, such as higher component density and smaller components for mounting, while having better performance under stress.
[0002] Ball Grid Array (BGA) technology is a surface mounting method mainly used for flip chips with the increasing demand for high-density mounting. The BGA includes an array of small-sized metal solder balls arranged on the bottom surface of the component. Correspondingly, the substrate includes an array of contact pads having the same pattern matching the solder balls. The placement of the component on the substrate is achieved through a reflow soldering process, in which the solder balls are heated, for example, using a reflow oven or by an infrared heater to melt. Surface tension keeps the component and the substrate aligned with the melted solder balls at a specific separation distance. After the solder balls cool and solidify, a solder joint is formed between the component and the substrate.
[0003] The solder balls connecting the substrate and the component are prone to breakage when subjected to mechanical and thermal stresses, which in turn may cause the failure of the entire device. For example, bending, flexing, vibration between the substrate and the BGA, and differences in the coefficient of thermal expansion may potentially cause the solder joint to break. There is a need to develop viable and effective techniques to strengthen the solder joint to prevent failure. Summary of the Invention
[0004] This Summary of the Invention is provided to introduce a series of concepts further described below in the Detailed Description. This Summary of the Invention is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to help limit the scope of the claimed subject matter.
[0005] In some aspects, the techniques described herein relate to a method of manufacturing an electronic component, the method comprising: generating an array of voids in a sheet; applying a first adhesive layer to a first surface of the sheet and a second adhesive layer to a second surface of the sheet to form an inserter; attaching the inserter to a component including a ball grid array of solder balls through the first adhesive layer; mounting the inserter to a substrate including an array of contact pads through the second adhesive layer, the pattern of the array of contact pads matching the ball grid array on the component; and performing reflow soldering on the solder balls at a temperature above the melting point of the solder balls, wherein during the reflow soldering, the first adhesive layer and the second adhesive layer are cured to form an underfill between the component and the substrate.
[0006] In some aspects, the techniques described herein relate to methods that further include aligning voids with a ball grid array of solder balls such that each of the voids in the sheet accommodates one of the solder balls.
[0007] In some aspects, the techniques described herein relate to methods in which an array of voids is generated prior to applying a first adhesive layer.
[0008] In some aspects, the techniques described herein relate to methods in which an array of voids is generated after applying at least one of a first adhesive layer and a second adhesive layer.
[0009] In some aspects, the techniques described herein relate to methods that further include semi-curing at least one of a first adhesive layer and a second adhesive layer prior to mounting an inserter to a substrate.
[0010] In some aspects, the techniques described herein relate to methods that further include attaching a plurality of inserters to one or more corners and / or one or more edges of a component.
[0011] In some aspects, the techniques described herein relate to methods in which the sheet is made of a material selected from ceramics, polymers, fiberglass, and insulated metal.
[0012] In some aspects, the techniques described herein relate to methods in which the voids are generated by drilling or wire weaving.
[0013] In some aspects, the techniques described herein relate to an electronic component that includes: a component including a ball grid array of solder balls; a substrate including an array of contact pads, the pattern of the array of contact pads matching the ball grid array on the component; and an inserter between the component and the substrate, where the inserter includes: a sheet having an array of voids, each void accommodating one of the solder balls; a first adhesive layer between the sheet layer and the component; and a second adhesive layer between the sheet layer and the substrate.
[0014] In some aspects, the techniques described herein relate to an electronic component in which the sheet is made of a material selected from ceramics, polymers, fiberglass, and insulated metal.
[0015] In some aspects, the techniques described herein relate to an electronic component in which the inserter is disposed at a corner or an edge of the component.
[0016] In some aspects, the techniques described herein relate to an electronic component in which a plurality of inserters are disposed at one or more corners and / or one or more edges of the component.
[0017] Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 shows a cross-sectional view of an electronic component manufactured by a conventional underfill process.
[0019] Figure 2 FIG. shows a cross-sectional view of an electronic component according to one or more embodiments of the present disclosure.
[0020] Figure 3 is a schematic diagram showing a surface mounting method for an electronic component according to one or more embodiments of the present disclosure.
[0021] Figure 4 is a cross-sectional view of an inserter according to one or more embodiments of the present disclosure.
[0022] Figure 5 is a cross-sectional view of an inserter according to one or more embodiments of the present disclosure.
[0023] Figure 6 is a flowchart of a surface mounting method for an electronic component according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION
[0024] The detailed embodiments of the present disclosure will now be described in detail below with reference to the drawings. For consistency, the same elements in each figure are denoted by the same reference numerals.
[0025] In the following detailed description of the embodiments of the present disclosure, many specific details are set forth to provide a more thorough understanding of the present invention. However, it will be apparent to those of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known features are not described in detail to avoid unnecessarily complicating the description.
[0026] "Solder balls" (also known as "bumps" or "bonding bumps") are solder balls that provide contact between components and substrates and between stacked components. The solder balls connecting the substrate and the components are prone to breakage when subjected to mechanical and thermal stresses, which in turn may cause the entire device to fail. As shown in the exemplary electronic assembly illustrated in FIG. 1, underfill may be applied after the soldering process to overcome this problem. The electronic assembly 100 in FIG. 1 includes a component 110 and a substrate 120. The component 110 includes an array of solder balls 111 (also known as BGA) soldered to the surface facing the substrate 120. The substrate 120 includes an array of contact pads 121 having the same pattern as the solder balls 111. The component 110 and the substrate 120 are connected by a reflow soldering process in which the solder balls 111 are heated, for example, using a reflow oven or by an infrared heater, to melt, such that surface tension causes the molten solder balls to hold the component 110 and the substrate 120 aligned at a specific separation distance defined by the size of the solder balls 111. After the solder balls have cooled and solidified, each contact pad 121 is connected to the corresponding solder ball 111, such that the component and the substrate are electrically connected through the solder balls 111 and the contact pads 121.
[0027] A liquid-phase electrically insulating adhesive can be dispensed at the corners or edges of the component 110 using a dispenser 102. The dispenser can be a syringe, or more specifically, an automatic syringe. The electrically insulating adhesive can flow under capillary action to fill the gap between the component 110 and the substrate 120. The adhesive is then thermally cured in place to form an underfill 132 around the solder balls and contact pads that constitute the electrical connection, thereby making the solid connection significantly less prone to breakage. The formation of the underfill 132 also leaves a small space for the formation of metal whiskers, thereby eliminating the risk of short circuits.
[0028] In the example shown in FIG. 1, the formation of the underfill is performed after the mounting of the component and the substrate and the reflow soldering of the solder balls. That is, in the manufacture of the electronic assembly shown in FIG. 1, the reflow soldering process and the formation of the underfill 132 are two independent processes. On the other hand, the present disclosure provides techniques that can achieve one-step reflow soldering and underfill formation, including apparatuses and methods that utilize a double-sided coated inserter between the component and the substrate.
[0029] This document will describe specific embodiments of an electronic component and a surface mounting method with reference to the accompanying drawings. In this disclosure, the thickness direction of the sheet is defined as the vertical direction Z. One direction perpendicular to the vertical direction Z indicates the direction X, and the other direction perpendicular to the two directions of the vertical direction Z and the direction X indicates the direction Y. Along the vertical direction Z, the component side and the substrate side of the sheet respectively mean the upper (top) side and the lower (bottom) side. The horizontal plane means a plane along the directions X and Y, for example, a plane parallel to the top surface of the sheet. In addition, a plan view means observing the target object from the vertical direction Z. Unless otherwise specified, a sectional view means a cross-sectional view of the object when cut along a plane in the vertical direction Z.
[0030] Figure 2 An electronic component according to one or more embodiments of this disclosure is shown. The "electronic component" in this disclosure refers to the process of collecting, soldering, and / or integrating electronic components and circuits to perform one or more tasks, and the product manufactured through such a process. As Figure 2 shown, the electronic component includes a component 210, a substrate 220, and an inserter 230 between the component 210 and the substrate 220.
[0031] The component 210 includes an array of solder balls 211 soldered to the bottom surface facing the substrate 220. The component 210 can be an electronic component, which can be any basic discrete device or physical entity in an electronic system for influencing electrons and / or their associated fields, or can be an integrated circuit (IC) component, which is a component of electronic components on a flat semiconductor material (e.g., a silicon wafer) connected together to achieve a common goal. Examples of the component 210 can include resistors, capacitors, inductors, discrete semiconductors, and integrated circuits. In one or more embodiments, the component 210 can be a microprocessor, for example, a central processing unit.
[0032] The solder balls 211 are solid metal spheres, and their diameters vary based on the component design, depending on the desired separation distance for preventing bridging defects or short circuits and / or the desired electronic device density for ensuring high performance. The diameter of the solder balls 211 can be in the range from about 100 μm to about 1000 μm, or from about 200 μm to about 800 μm. The solder balls 211 can be made of a metal or a metal alloy, and can include, for example, tin (Sn), silver (Ag), copper (Cu), bismuth (Bi), and their compositions.
[0033] The substrate 220 is a supporting base on which components and their connections are built. The substrate 220 can be doped or undoped silicon, or the active layer of a silicon-on-insulator (SOI) substrate. The substrate can include semiconductor materials such as germanium, silicon carbide, gallium arsenide, gallium phosphide, indium phosphide, indium arsenide, indium antimonide alloy semiconductors, or combinations thereof. The substrate can also include conductive layers, each designed with a pattern of traces, planes, or other features printed or etched on the conductive material. Components on the substrate can be interconnected through metallization patterns in one or more dielectric layers to form an integrated circuit. In one or more embodiments, the substrate can be a printed circuit board (PCB).
[0034] The substrate 220 includes an array of contact pads 221 having the same pattern as the solder balls 211. The contact pads 221 can be made of a metal or metal alloy such as tin (Sn), silver (Ag), gold (Au), copper (Cu), nickel (Ni), palladium (Pd), or combinations thereof. When joined together by reflow soldering, the solder joints formed by the connected solder balls 211 and contact pads 221 electrically connect the components and the substrate.
[0035] The inserter 230 includes a sheet 231 and an underfill 232. The inserter 230 provides beneficial effects in strengthening the solder joints, enhancing the resistance of the electronic assembly, and absorbing the thermal expansion mismatch between the components and the substrate, thereby avoiding fracture when subjected to mechanical stress and thermal stress. The sheet 231 has a planar shape with a plurality of voids, each void accommodating a solder ball 211. In other words, within the area of the sheet 231, the voids in the sheet 231 have the same pattern as the solder balls. The sheet 231 can be made of a rigid material such as ceramic, polymer (e.g., polyimide, epoxy resin), fiberglass, insulated metal (e.g., stainless steel), or combinations thereof. In one or more embodiments, the sheet 231 can be made of a prepreg material such as fiberglass with a semi-cured resin. The sheet 231 is non-conductive.
[0036] The underfill 232 is an adhesive material that is fluid at room temperature or low temperature and cures at an elevated temperature to form a uniform and void-free layer. The underfill can be a polymer such as epoxy resin, silicone resin, and acrylic. The underfill can be in the form of a gel or a film. The underfill 232 can include one or more adhesives, for example, a first adhesive mainly distributed between the sheet 231 and the component 210 and a second adhesive mainly distributed between the sheet 231 and the substrate 220. Between the solder balls and the contact pads, the underfill can include a mixture of the first adhesive and the second adhesive.
[0037] In one or more embodiments, both the first adhesive and the second adhesive are one-component adhesives and are thermally curable. For example, each of the first adhesive and the second adhesive is composed of epoxy resin. In other embodiments, one of the first adhesive and the second adhesive is a two-component adhesive that is thermally curable and semi-curable under ultraviolet light, while the other is a one-component adhesive that is thermally curable. For example, the first adhesive may be composed of acrylic acid, and the second adhesive may be composed of epoxy resin.
[0038] The electronic component 200 may include a plurality of inserters described herein. In some implementations, the inserters may be disposed at the corners or edges of the electronic component because these areas may experience higher mechanical or thermal stresses.
[0039] A surface mounting method for an electronic component according to one or more embodiments of the present disclosure is shown in Figure 3 the scheme of. Figure 4 and Figure 5 shows a cross-sectional view of the inserter during processing in the surface mounting method. The manufacturing of the electronic component starts with a sheet 331 having an array of voids 333. The sheet 331 may be made of a rigid material such as ceramic, polymer (e.g., polyimide, epoxy resin), fiberglass, and insulated metal (e.g., stainless steel). A pattern of voids 333 is generated to match the solder balls 311 on the corresponding component 310. Each void 333 may have a circular shape and a diameter slightly larger than the diameter of each solder ball 311. In one or more embodiments, an array of voids 333 in the form of through-holes may be generated by drilling (or punching). For example, in some implementations, the sheet is a non-conductive sheet without voids, and the array of voids is generated by drilling the non-conductive sheet using a laser. In other embodiments, the sheet 331 may be a mesh prepared by wire weaving or other mesh manufacturing techniques. For example, the sheet may be a fiberglass mesh or a stainless steel mesh coated with an insulating material (e.g., a coating of a polymer such as polyimide). The insulating material may be coated by any known technique in the art such as physical vapor deposition (PVD) or spraying.
[0040] The inserter 330 is formed by applying a first adhesive layer 334 to the upper surface of the sheet 331 and a second adhesive layer to the lower surface of the sheet 331. The first adhesive layer 334 and the second adhesive layer 335 can be applied one after another or simultaneously using any known technique in the art. In some implementations, the liquid-phase adhesive can be applied by drop casting, spraying, or electrodeposition. In some implementations, the adhesive can be applied by dipping the sheet into an adhesive solution and then performing a semi-curing process to fix the adhesive. The semi-cured adhesive can have a certain fluidity but cannot flow freely. For example, the semi-cured adhesive can be in a gel state so that it will not fall off or become misaligned during subsequent processing. In some implementations, the adhesive is applied only by dispensing droplets on the surface of the sheet. In some implementations, the adhesive in the form of a film can be applied directly.
[0041] The thickness of the sheet 331 can range from about 0.05 mm to about 0.6 mm. The thickness of the first adhesive layer 334 can range from about 20 μm to about 300 μm. The thickness of the second adhesive layer 335 can range from about 20 μm to about 300 μm. The total thickness of the sheet and the two adhesive layers cannot exceed the height of the solder ball before subsequent installation and cannot exceed the height of the solder joint after reflow soldering. The thickness of the sheet can be controlled by rolling the sheet before applying the first adhesive layer and / or the second adhesive layer. Alternatively, rolling can be performed after applying the first adhesive layer and / or the second adhesive layer, thereby controlling the total thickness of the inserter.
[0042] In one or more embodiments, the inserter 330 is manufactured according to the Figure 3 sequence shown, where the first adhesive layer 334 and the second adhesive layer 335 are applied to the sheet 331 having voids 333. However, those of ordinary skill in the art will recognize that the present disclosure is not limited thereby, and the sequence can be changed as needed. In one or more embodiments, the voids can be created (e.g., by drilling) after applying the first adhesive layer to the sheet or after applying the first adhesive layer and the second adhesive layer to the sheet. For example, in some implementations, when the sheet is a fiberglass mesh, the first adhesive layer and the second adhesive layer can be applied to the mesh surface before laser drilling. In some implementations, the sheet can be made of a stainless steel mesh coated with an insulating (non-conductive) material, and the voids in the insulated stainless steel mesh can be customized by electroforming and then laser drilling.
[0043] The inserter 330 having the sheet and the adhesive layers stacked vertically together is then attached to the component 310 through the first adhesive layer 334. In Figure 3In the example shown, four inserters 330 are attached at the four corners of the component 310 because the corners and / or edges may experience high mechanical or thermal stress. However, those of ordinary skill in the art will recognize that the present disclosure is not limited to the example shown in the figures. In actual applications, the shape, size, arrangement, and number of the inserters may vary. For example, two inserters may be used to cover the four corners and two edges of the component. One inserter may be used to cover the four edges surrounding the perimeter of the component, any desired area of the component, or the entire component.
[0044] In Figure 4 is shown a cross-sectional view of the inserter during attachment. As Figure 3 and Figure 4 shown, alignment may be performed prior to attachment to ensure that the positions of the solder balls 311 match the voids 333, where each void accommodates a solder ball after attachment. An alignment system 340 (e.g., a charge-coupled device (CCD)) automatic alignment imaging device may be used to inspect one or more markers on the inserter (e.g., on one of the adhesive layers) or the profile of the inserter 330. A pick-and-place tool may be used to pick up the component 310 and place the component 310 in place under the instruction of the alignment system. A fixing device 350 may be used to support the inserter 330 during attachment. In one or more embodiments, a release film may be used to temporarily cover the second adhesive layer when attaching the first adhesive layer. The fixing device 350 may be designed to have a pattern of voids identical to those of the inserter 330. When attaching the component 310 and the inserter 330, pressure may be applied to the component 310. Thus, the bottom surface of the component 310 is attached to the inserter 330 through the first adhesive layer 334, where the solder balls 311 are received in the voids 333.
[0045] The combined structure of the inserter 330 and the component 310 may be mounted to the substrate 320. In Figure 5 is shown a cross-sectional view of the inserter during the mounting process. After attachment of the component and mounting to the substrate, the first adhesive layer 334 and the second adhesive layer 335 flow to fill the gap between the component 310 and the substrate 320. In one or more embodiments, the first adhesive is semi-cured to a gel state after attachment and before mounting to prevent the first adhesive layer from falling off or misaligning during mounting or moving the combined structure, and to reduce processing risks. The elevated temperature for pre-curing may range from about 80 °C to about 140 °C for about 1 minute to about 30 minutes.
[0046] The combined structure of the inserter 330 and the component 310 is fixed to the substrate 320 by reflow soldering. A heating system such as a reflow oven can be used to provide an elevated temperature during the reflow soldering process. The reflow soldering process can include a first stage when the temperature increases from about room temperature to an elevated temperature above the melting point of the solder balls 311, a second stage when the temperature is maintained at the elevated temperature for a certain period of time, and a third stage of cooling. In the first stage, the temperature can increase at a rate of 1°C to 5°C per second, or at a rate of 1°C to 3°C per second. The elevated temperature can be in the range of about 140°C to about 250°C. The solder balls 311 can melt at the elevated temperature, and the surface tension causes the melted solder balls to keep the component 110 and the substrate 120 aligned at a specific separation distance. After the solder balls 311 cool and solidify, each contact pad 321 is connected to the corresponding solder ball 311, so that the component 310 and the substrate 320 are electrically connected through the solder balls 311 and the contact pads 321.
[0047] During reflow soldering, the first adhesive layer 334 and the second adhesive layer 335 are also cured at the elevated temperature to form an underfill between the component 310 and the substrate 320. That is, forming the underfill and reflow soldering are achieved in the same step.
[0048] Figure 6 The flowchart in shows a surface mounting method described in one or more embodiments of the present disclosure. The surface mounting method can include a step S601 of generating an array of voids in a sheet. The sheet can be made of a material selected from ceramics, polymers, fiberglass, and insulated metals. The voids can be prepared by wire weaving or drilling in the sheet.
[0049] In one or more embodiments, the surface mounting method can include a step S602 of forming an inserter by applying a first adhesive layer to a first surface of the sheet and a second adhesive layer to a second surface of the sheet. The first adhesive layer and the second adhesive layer can be applied by any known technique in the art such as drop casting, spraying, electrodeposition, dipping in an adhesive solution, and droplet dispensing. The generation of the voids in S601 can be performed before the formation of the inserter in S602. Alternatively, the generation of the voids can be performed after applying the first adhesive layer and before applying the second adhesive layer, or can be performed after applying the first adhesive layer and the second adhesive layer.
[0050] In one or more embodiments, the surface mounting method can include a step S603 of attaching the inserter to a component including a ball grid array of solder balls through the first adhesive layer. To ensure that each of the voids on the sheet corresponds to each of the solder balls, the surface mounting method can include aligning the voids with the ball grid array of the solder balls so that each of the voids on the sheet accommodates one of the solder balls.
[0051] In one or more embodiments, the surface mounting method may include step S604 of mounting an inserter to a substrate including an array of contact pads whose pattern matches the ball grid array on the component through a second adhesive layer. In one or more embodiments, at least one of the first adhesive layer and the second adhesive layer is semi-cured before mounting the inserter to the substrate. The first adhesive layer and / or the second adhesive layer is semi-cured or uncured before mounting and may still have fluidity during mounting so as to flow and fill the gap between the component and the substrate.
[0052] In one or more embodiments, the surface mounting method may include step S605 of forming an underfill between the component and the substrate by curing the first adhesive layer and the second adhesive layer that have filled the gap therebetween. During the curing process, the solder balls are connected to the contact pads by reflow soldering the solder balls at a temperature higher than the melting point of the solder balls. Both curing and reflow soldering are performed at an elevated temperature and in one step.
[0053] One or more embodiments described in the present disclosure provide an electronic component and a surface mounting method that achieve reflow soldering and underfill formation in a single step. By using a double-sided coated inserter between the component and the substrate, underfill formation can be performed during reflow soldering. Therefore, the underfill process after reflow soldering can be eliminated. The inserter can provide stiffness to the component and reduce the likelihood of failure caused by thermal and / or mechanical stress.
[0054] Although only several configurations are shown in the drawings, those of ordinary skill in the art will recognize that the present disclosure can be applied to various shapes, sizes, materials, and arrangements, and many modifications can be made in the exemplary embodiments without substantially departing from the invention. Accordingly, all such modifications are intended to be included within the scope of the present disclosure as defined by the appended claims.
Claims
1. A method of manufacturing an electronic component, comprising: generating an array of voids in a sheet; forming an inserter by applying a first adhesive layer to a first surface of the sheet and a second adhesive layer to a second surface of the sheet; attaching the inserter to a component including a ball grid array of solder balls through the first adhesive layer; mounting the inserter to a substrate including an array of contact pads through the second adhesive layer, the pattern of the array of contact pads matching the ball grid array on the component; and forming an underfill between the component and the substrate by curing the first adhesive layer and the second adhesive layer, wherein forming the underfill includes connecting the solder balls to the contact pads by reflow soldering the solder balls at a temperature higher than the melting point of the solder balls.
2. The method according to claim 1, further comprising aligning the voids with the ball grid array of the solder balls such that each of the voids in the sheet accommodates one of the solder balls.
3. The method according to claim 1 or 2, wherein, the array of voids is generated in the sheet before applying the first adhesive layer.
4. The method according to claim 1 or 2, wherein, the array of voids is generated after applying at least one of the first adhesive layer and the second adhesive layer.
5. The method according to any one of claims 1 to 4, wherein, the array of voids is generated by drilling or wire weaving.
6. The method according to any one of claims 1 to 5, further comprising semi-curing at least one of the first adhesive layer and the second adhesive layer before mounting the inserter to the substrate.
7. The method according to any one of claims 1 to 6, further comprising attaching additional inserters to one or more corners and / or one or more edges of the component.
8. The method according to any one of claims 1 to 7, wherein, the sheet is made of a material selected from ceramics, polymers, fiberglass, and insulated metals.
9. An electronic component, comprising: a component including a ball grid array of solder balls; a substrate including an array of contact pads, the pattern of the array of contact pads matching the ball grid array on the component; and an inserter between the component and the substrate, wherein the inserter includes: a sheet having an array of voids, each void accommodating one of the solder balls; and an underfill that fills the gap between the component and the substrate and includes a first adhesive layer between the sheet and the component and a second adhesive layer between the sheet and the substrate.
10. The electronic component according to claim 9, wherein, the sheet is made of a material selected from ceramics, polymers, fiberglass, and insulated metals.
11. The electronic component according to claim 9 or 10, wherein, the inserter is disposed at a corner or an edge of the component.
12. The electronic component according to any one of claims 9 to 11, wherein, A plurality of the inserters are provided at one or more corners and / or one or more edges of the component.