Electronic package and method for forming an electronic package

Abstract

A method for forming an electronic package is provided, comprising: providing a substrate, the substrate including a first conductive pad and a second conductive pad, a terminal of a first electronic component to be mounted to the first conductive pad, a terminal of a second electronic component to be mounted to the second conductive pad, the first conductive pad adjacent to the second conductive pad; forming a first solder paste on the first conductive pad; reflowing to form a first solder layer; forming a second solder paste on the first solder layer and the second conductive pad; placing the first and second components on the substrate, the terminal of the first electronic component in contact with the second solder paste on the first solder layer, and the terminal of the second electronic component in contact with the second solder paste on the second conductive pad; and reflowing the second solder paste to mount the first and second electronic components.

Description

Technical Field

[0001] This application relates generally to semiconductor technology, and more specifically to an electronic package and a method for forming the electronic package. Background Technology

[0002] The semiconductor industry has always faced the challenge of complex integration as consumers demand lighter, smaller, and higher-performance electronics with increasingly sophisticated functionality. Traditionally, electronic packaging requires attaching various electronic components to a substrate to achieve desired electrical interconnections. To accommodate these components within the limited space on the substrate, a compact layout can be implemented where the components are very close to each other. However, as explained below, in such a compact layout, undesirable solder bridges can form between adjacent components, particularly between adjacent terminals of two components, during the soldering process of attaching the components to the substrate.

[0003] refer to Figure 1A and Figure 1B The diagram shows a cross-sectional view of a portion of substrate 100 before and after soldering or reflow processes. For example, substrate 100 includes two conductive pads 110 and 120 formed thereon, each of which is used to mount a terminal of one of two adjacent electronic components 150 and 160 using surface mount technology (SMT). Figure 1A As shown, solder paste 130 and 140 are applied to the first conductive pad 110 and the second conductive pad 120, respectively. The terminal 151 of the first electronic component 150 is placed on the first conductive pad 110 via solder paste 130, while the terminal 161 of the second electronic component 160 is placed on the second conductive pad 120 via solder paste 140. (Reference) Figure 1B After the reflow process, terminals 151 and 161 are metallurgically bonded to the reflowed solder paste, thereby forming electrical connections with conductive pads 110 and 120, respectively.

[0004] However, there is a risk of solder bridging forming between the two conductive pads 110 and 120 before and after the reflow step. First, when electronic components 150 and 160 are placed onto the substrate 100, solder paste may be extruded from the corresponding conductive pads. Second, during the reflow process, the solder paste may melt and then flow to cover extended areas on the substrate 100 that may extend beyond the conductive pads. As a result, the distance D1 between the reflowed solder paste on the two adjacent conductive pads 110 and 120 may be too small, even zero, increasing the risk of unwanted solder bridging or short circuits between the two electronic components 150 and 160. In other words, adjacent solder paste may come into contact with each other after reflow or at a later stage. This can lead to failure of the electronic package and reduce the overall yield of the electronic package.

[0005] Therefore, an improved method for forming electronic packages is needed. Summary of the Invention

[0006] The purpose of this application is to provide a method for forming electronic packages that improves the ability to avoid solder bridges or short-circuit defects in electronic packages.

[0007] According to one aspect of this application, a method for forming an electronic package is provided, comprising: providing a substrate, wherein the substrate includes a first conductive pad and a second conductive pad, terminals of a first electronic component being mounted to the first conductive pad, and terminals of a second electronic component being mounted to the second conductive pad, wherein the first conductive pad and the second conductive pad are adjacent; forming a first solder paste on the first conductive pad; reflowing the first solder paste on the first conductive pad to form a first solder layer; forming second solder paste on the first solder layer and the second conductive pad, respectively; placing the first electronic component and the second electronic component on the substrate such that the terminals of the first electronic component contact the second solder paste on the first solder layer, and the terminals of the second electronic component contact the second solder paste on the second conductive pad; and reflowing the second solder paste to mount the first electronic component and the second electronic component onto the substrate.

[0008] According to another aspect of this application, an electronic package is provided, which is formed using the above-described method.

[0009] According to another aspect of this application, an electronic device is provided, comprising: a substrate; a first conductive pad and a second conductive pad on the substrate, wherein the first conductive pad and the second conductive pad are adjacent; a first solder layer formed on the first conductive pad; a second solder layer formed on the first solder layer and the second conductive pad respectively; a first electronic component whose terminals are mounted on the first conductive pad via the first solder layer and the second solder layer; and a second electronic component whose terminals are mounted on the second conductive pad via the second solder layer.

[0010] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the invention. Furthermore, the accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with this specification, serve to explain the principles of the invention. Attached Figure Description

[0011] The accompanying drawings referenced herein form part of this specification. The features shown in the drawings are merely illustrative of some embodiments of this application, and not all embodiments of this application, unless the specific embodiments clearly indicate otherwise, and the reader of this specification should not draw the contrary inference.

[0012] Figure 1A A cross-sectional view of a portion of a conventional substrate before welding is shown.

[0013] Figure 1B A cross-sectional view of a portion of a conventional substrate after welding is shown.

[0014] Figure 2 A flowchart of a method for forming an electronic package according to an embodiment of this application is shown.

[0015] Figures 3A to 3F An embodiment according to this application is shown. Figure 2 A cross-sectional view of the steps of the method shown.

[0016] Figure 4A and 4B Another embodiment according to this application is shown. Figure 2 Cross-sectional views of the two steps of the method shown.

[0017] Figure 5 The use of embodiments according to this application is illustrated. Figure 2 A partial cross-sectional view of the electronic package formed by the method shown.

[0018] Figure 6 A partial top view of an electronic device according to an embodiment of this application is shown.

[0019] The same or similar reference numerals will be used throughout the accompanying drawings to refer to the same or corresponding parts. Detailed Implementation

[0020] The following detailed description of exemplary embodiments of this application takes into account the accompanying drawings, which form a part of the description. The drawings illustrate specific exemplary embodiments in which this application may be practiced. The detailed description, including the drawings, describes these embodiments in sufficient detail to enable those skilled in the art to practice this application. Those skilled in the art can further utilize other embodiments of this application and make logical, mechanical, and other changes without departing from the spirit or scope of this application. Therefore, the reader of the following detailed description should not interpret it in a limiting sense, and only the appended claims define the scope of the embodiments of this application.

[0021] In this application, unless otherwise specified, the use of the singular includes the plural. In this application, unless otherwise specified, the use of “or” means “and / or”. Furthermore, the use of the term “including” and other forms such as “includes” and “included” is not restrictive. Additionally, unless otherwise specified, terms such as “element” or “component” cover both elements and components comprising one unit and elements and components comprising more than one sub-unit. Furthermore, the section headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described.

[0022] As used herein, for ease of description, spatial relative terms such as “below,” “under,” “above,” “on top,” “upper,” “lower,” “left,” “right,” “vertical,” “horizontal,” “side,” etc., are used to describe the relationship between one element or feature shown in the figures and one or more other elements or features. In addition to the orientations depicted in the figures, spatial relative terms are also intended to cover different orientations of the device in use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein shall be interpreted accordingly. It should be understood that when an element is referred to as “connected to” or “coupled to” another element, it may be directly connected to or coupled to the other element, or there may be intermediate elements present.

[0023] In electronic devices, such as electronic packages, various components can be integrated onto the same substrate. Traditionally, these components are attached to the substrate using a soldering process. To accommodate components within the limited space of the substrate, careful design of the component layout is required. For example, if no signal or voltage transmission is needed between adjacent components, electrical isolation between them should be ensured. However, as mentioned above, if the distance between adjacent conductive pads is too small, solder paste in adjacent conductive pads may form solder bridges after the reflow process, resulting in undesirable electrical connections, such as short circuits. To address the above problems, this application proposes a method for forming electronic packages that improves the separation and isolation between adjacent electronic components. The method prevents significant reshaping of the solder paste during the reflow process, thereby avoiding undesirable solder bridges or short circuits.

[0024] Figure 2 A flowchart of a method 200 for forming an electronic package according to an embodiment of this application is shown. Figures 3A to 3F A cross-sectional view of the steps of method 200 according to an embodiment of this application is shown.

[0025] like Figure 2As shown, method 200 begins with step 201, in which a substrate is provided. The substrate includes a first conductive pad on which terminals of a first electronic component will be mounted, and a second conductive pad on which terminals of a second electronic component will be mounted. The first conductive pad is positioned adjacent to the second conductive pad. In step 202, a first solder paste is applied to the first conductive pad. In step 203, the first solder paste on the first conductive pad is reflowed to form a first solder layer. In step 204, a second solder paste is applied to the first solder layer and the second conductive pad. The second solder paste may have different melting characteristics than the first solder paste. For example, the second solder paste may have a lower melting temperature than the first solder paste. It is understood that the first and second solder pastes can be applied using any suitable method, such as stencil printing, screen printing, dot matrix transfer, or inkjet printing.

[0026] Next, in step 205, the first and second electronic components are placed on the substrate such that the terminals of the first electronic component contact the second solder paste on the first solder layer, and the terminals of the second electronic component contact the second solder paste on the second conductive pad. In some preferred embodiments, the first and second electronic components are placed on the substrate such that the terminals of the first electronic component are further aligned with the first conductive pad, and the terminals of the second electronic component are also further aligned with the second conductive pad. It is understood that the first electronic component may have two or more terminals, and the terminal in contact with the second solder paste is one of the two or more terminals. Similarly, the second electronic component may have two or more terminals, and the terminal in contact with the second solder paste is one of the two or more terminals. In step 206, the second solder paste is reflowed to mount the first and second electronic components onto the substrate. Reference will be made below to... Figures 3A to 3F Further details Figure 2 The steps of the method shown.

[0027] Specifically, such as Figure 3A As shown, a substrate 300 is provided, the substrate 300 including a first conductive pad 310 and a second conductive pad 320. It should be understood that the first and second conductive pads 310 and 320 can take any suitable shape, preferably a rounded rectangle. The conductive pad 310 is used to mount the terminal of a first electronic component (not shown), and the conductive pad 320 is used to mount the terminal of a second electronic component (not shown) in a later step. Reference Figure 3A The distance D2 between the first conductive pad 310 and the second conductive pad 320 can be very small, for example, less than 65 μm, preferably in the range of 40 μm to 60 μm. It should be noted that... Figure 3AFor illustrative purposes only, substrate 300 may include any number of conductive pads arranged in any desired layout, and one or more additional conductive pads on substrate 300 may also be used to mount other terminals of the first or second electronic component, or terminals of other electronic components. In some examples, conductive pads 310 and 312 may be formed of a metal such as copper as contact pads.

[0028] refer to Figure 3B For example, the first solder paste 330 is applied to the first conductive pad 310 via a deposition process. In some other embodiments, the first solder paste 330 is applied to or otherwise formed onto the first conductive pad 310 via stencil printing, screen printing, dot matrix transfer, or inkjet printing. It is understood that the substrate 300 may have multiple conductive pads, and the first solder paste may be formed on the substrate 300 simultaneously during the same process.

[0029] refer to Figure 3C The first solder paste 330 on the first conductive pad 310 is reflowed to form a first solder layer 331. In some embodiments, the first solder paste 330 on the first conductive pad 310 is heated in an oven or using a hot air reflow system to melt it, and then the first solder layer 331 is formed after a subsequent cooling stage. In other words, the reflow process may raise the temperature of the first solder paste 330 above its melting temperature. In some embodiments, the first solder layer 331 may be hardened and cured after the reflow process. In other embodiments, the first solder layer 331 may remain in a mixed state of solid and liquid phases after the reflow process.

[0030] It is understood that after the reflow process, the first solder paste 330 can be transformed into a first solder layer 331, which can occupy a certain space and area on the first conductive pad 310. Therefore, the amount of the first solder paste 330 applied or otherwise formed onto the first conductive pad 310 can be controlled to prevent excessive amounts of the first solder paste 330 from flowing out of the first conductive pad 310 and onto the surface of the substrate 300. Figure 3C As shown, the first solder layer 331 may have a convex shape or form a substantially flat plane, depending on the material of the first solder layer 331 (particularly surface tension). In some embodiments, the amount of first solder paste 330 applied or otherwise formed onto the first conductive pad 310 may be controlled to form a first solder layer 331 with a height ranging from 5 to 25 micrometers.

[0031] Next, as Figure 3DAs shown, a second solder paste 340 is applied to a first solder layer 331 on a first conductive pad 310 and then to a second conductive pad 320. The composition of the second solder paste 340 may differ from that of the first solder paste 330. Specifically, the first solder paste 330 may have a higher melting temperature than the second solder paste 340. Therefore, if the substrate 300 is heated to a temperature between the melting temperature of the first solder layer 331 and the melting temperature of the second solder paste 340, the second solder paste 340 may melt, while the first solder layer 331 may not melt. In some embodiments, the first solder paste is a Sn5Sb solder with a melting temperature of approximately 243°C or a Sn10Sb solder with a melting temperature of approximately 248°C. The second solder paste is a SAC305 solder with a melting temperature of approximately 217°C.

[0032] Since the second solder paste 340 is formed on the first conductive pad 310 having the first solder layer 331 and the second conductive pad 320 without the first solder layer 331, the amount of the second solder paste 340 on the first conductive pad 310 can differ from the amount of the second solder paste 340 on the second conductive pad 320. In some embodiments, the amount of the second solder paste 340 applied to the first solder layer 331 is less than the amount of the second solder paste 340 applied to the second conductive pad 320. This ensures that there is no significant height difference between the solder layers formed on the two conductive pads 310 and 320. In this way, the pre-formed first solder layer 331 substantially does not affect the height alignment between adjacent terminals of the two electronic components to be mounted. In some embodiments, the amount of the second solder paste 340 applied to the first solder layer 331 is less than the amount of the first solder paste 330 applied to the first conductive pad 310, thereby ensuring that the first solder layer 331 has sufficient height to maintain an appropriate distance between the reflowed solder layers below the adjacent terminals of the electronic components. In some embodiments, in addition to the first solder layer 331, the second solder paste 340 may also be formed on the first conductive pad 310 (e.g., a small amount of the second solder paste 340 flows down), but its main body remains on top of the first solder layer 331. In some embodiments, the second solder paste 340 is applied by stencil printing onto the first solder layer 331 and the second conductive pad 320. The stencil used for applying the solder paste will be... Figure 4A and 4B This is shown in more detail below. It can be understood that other deposition processes, such as dot transfer or inkjet printing, can be used to apply the second solder paste 340.

[0033] refer to Figure 3EA first electronic component 350 and a second electronic component 360 are placed on a substrate 300 such that the terminal 351 of the first electronic component 350 contacts the second solder paste 340 on the first solder layer 331, and the terminal 361 of the second electronic component 360 contacts the second solder paste 340 on the second conductive pad 320. In some embodiments, terminals 351 and 361 may be aligned with the first and second conductive pads, respectively. In some other embodiments, terminal 351 may be offset on the first conductive pad 310 without affecting the connection between terminal 351 and the first conductive pad 310 via the first solder layer 331 and the second solder paste 340. Similarly, terminal 361 may be offset on the second conductive pad 320 without affecting the connection between terminal 361 and the second conductive pad 320 via the second solder paste 340. As mentioned above, it should be noted that although Figure 3E The first electronic component 350 and the second electronic component 360 shown each have only one terminal, but they may include one or more additional terminals to form additional electrical connections with other conductive pads on the substrate 300. In a preferred embodiment, similar to terminal 351, other terminals of the first electronic component 350 may be placed and mounted on another conductive pad on the substrate 300 via another first solder layer and another second solder paste; similarly, similar to terminal 361, other terminals of the second electronic component 360 may be placed and mounted on another conductive pad on the substrate 300 via another second solder paste. In this way, electronic components 350 and 360 may not be tilted relative to the surface of the substrate 300.

[0034] Next, refer to Figure 3FThe second solder paste 340 is reflowed to form a second solder layer 341 on the first solder layer 331 and the second conductive pad 320, thereby mounting the first electronic component 350 and the second electronic component 360 onto the substrate 300. For example, the substrate 300 can be heated to raise its temperature to a temperature between the melting temperature of the second solder paste 340 and the melting temperature of the first solder layer 331. Taking terminal 361 as an example, the second solder paste 340 under terminal 361 is reflowed to mount terminal 361 onto the substrate 300. Specifically, terminal 361 is metallurgically bonded to the second solder layer 341, thereby establishing an electrical and mechanical connection between the terminal and the second conductive pad 320 on the substrate 300. Similarly, terminal 351 of the first electronic component 350 is metallurgically bonded to the second solder layer 341 on the first solder layer 331, thereby electrically and mechanically connecting the terminal to the first conductive pad 310 on the substrate 300. During the reflow process, the second solder paste 340 can melt and flow to cover a larger area. However, the second solder paste 340 may not flow out of the corresponding conductive pads 310 and 320 to avoid undesirable electrical connections with adjacent conductive pads. As previously mentioned, in some embodiments, a portion of the first solder paste 330 of the first solder layer 331 may also flow slightly during reflow. However, its flow is restricted because the first solder paste 330 has already been reflowed and has a higher melting temperature.

[0035] Due to the presence of the first solder layer 331 and / or by applying different amounts of the second solder paste 340 to the first solder layer 331 and the second conductive pad 320, compared to applying only one type of solder paste to the conductive pad, for example... Figure 1B The solder paste under terminals 151 and 161 shown has a smaller total amount of remolded second solder paste 340, and a larger distance D1 between the reflowed solder paste 340 under terminals 351 and 361. Therefore, the solder paste under adjacent terminals of electronic components is less likely to connect with each other and form solder bridges or short circuits.

[0036] Figure 4A and 4B Another embodiment according to this application is shown. Figure 2 Cross-sectional view of the two steps of applying solder paste in the method shown.

[0037] refer to Figure 4A First solder paste 430 is applied to first conductive pad 410 using a first stencil 470. The first stencil 470 is placed on the substrate, with the opening 471 in the first stencil 470 aligned with the first conductive pad 410. Then, the first solder paste 430 is applied directly to the first conductive pad 410 through the opening 471. (Reference) Figure 4BThe second solder paste 440 is applied to the second conductive pad 420 and the first solder layer 431, which is converted from the first solder paste through reflow, using a second stencil 480. Specifically, the second stencil 480 is placed on the substrate 400, with the first opening 481 and the second opening 482 of the second stencil 480 aligned with the first conductive pad 410 and the second conductive pad 420, respectively. The second solder paste 440 is applied to the first solder layer 431 through the first opening 481 in the second stencil 480, and to the second conductive pad 420 through the second opening 482 in the second stencil 480. Figure 4B As shown, the second template 480 includes a recessed portion 483 surrounding the first opening 481, the size and shape of which are designed to at least partially accommodate the first solder layer 431 during the paste application process. As a result, conventional paste dispensing methods, such as screen printing, can still be used for the application of the second solder paste 440, and the height difference between the first conductive pad 410 and the second conductive pad 420 caused by the first solder layer 431 does not adversely affect the application of the second solder paste 440. The recessed portion 483 can have any shape suitable for accommodating the first solder layer 431 during the paste application process. It is understood that the shape, height, or size of the recessed portion 483 can vary depending on the shape or size of the first solder layer 431 formed on the first conductive pad 410. In some embodiments, the diameter or width of the recessed portion can be larger than and proportional to the diameter or width of the first opening 481. In some examples, the diameter or width of the recessed portion can be 1.1 to 2 times the diameter or width of the first opening 481. It is understood that the combination of the recessed portion and the first opening 481 not only allows the first solder paste and the second solder paste to be applied to the first conductive pad, but also prevents them from flowing out of the first conductive pad during the application process.

[0038] It is also understood that the size and shape of openings 471, 481, and 482 can be appropriately designed to achieve the desired shape of the applied solder paste. In some embodiments, the first opening 481 is smaller than the second opening 482. Preferably, a screen printing process is used on the first and second stencils to deposit the desired amount of solder paste. In some embodiments, a squeegee is used to apply the solder paste material to the top surface of the first and second stencils. Preferably, the first and second stencils are made of a material such as metal. The stencils are typically manufactured using standard methods such as electroforming. It should be understood that the thickness of the first and second stencils can vary depending on the amount of solder paste to be applied. As previously stated, Figure 4A and 4B For illustrative purposes only. The substrate 400 may include any number of conductive pads, and the first and second stencils may also have a corresponding number of openings to apply different solder pastes to these pads or any layers formed on these pads.

[0039] Figure 5 The use of embodiments according to this application is illustrated. Figure 2 A partial cross-sectional view of the electronic package formed by the method shown. Figure 5 As shown, the electronic package includes a substrate 500 and at least two electronic components mounted on the substrate 500. A first conductive pad 510 and a second conductive pad 520 adjacent to the first conductive pad 510 are located on the substrate 500. The electronic components are electrically and mechanically connected to the substrate 500 via reflowed solder layers. Specifically, the electronic package has a first solder layer 531 formed on the first conductive pad 510 and a second solder layer 541 formed on the first solder layer 531 and the second conductive pad 520. A first electronic component 550 is located on the substrate 500, and its terminals 551 are mounted on the first conductive pad 510 via the first solder layer 531 and the second solder layer 541. A second electronic component 560 is located on the substrate 500, and its terminals 561 are mounted on the second conductive pad 520 via the second solder layer 541.

[0040] It should be understood that the substrate 500 may include any number of conductive pads arranged in any desired layout, and one or more additional conductive pads on the substrate 500 may also be used to mount other terminals of the first electronic component 550 or the second electronic component 560, or terminals of other electronic components. Furthermore, other adjacent conductive pads on the substrate 500 may have a solder layer similar to the solder layer formed beneath terminals 551 and 561.

[0041] Figure 6 A partial top view of an electronic device according to an embodiment of this application is shown. (As...) Figure 6 As shown, the electronic device includes a substrate 600 on which a plurality of components 601 to 609 are mounted. Each of the electronic components 601 to 609 is electrically and mechanically connected to the substrate 600 via two terminals. Taking two adjacent electronic components 604 and 605 as an example, terminal 651 of component 605 is positioned adjacent to terminal 642 of component 604. Terminal 651 is connected via a connection to the substrate 604 via a connection to the substrate 605 via a connection to the substrate 604. Figure 5 The double-layer solder layer structure beneath terminal 551 is electrically and / or mechanically connected to the substrate 600, while terminal 642 is electrically and / or mechanically connected to the substrate 600 via a solder layer structure identical to the single-layer solder layer structure beneath terminal 561. Therefore, the solder layers beneath adjacent terminals 651 and 642 are unlikely to contact each other and form solder bridges. Thus, compared to conventional solder layer structures, Figure 6 The electronic device shown reduces the risk of solder bridges and short-circuit defects between adjacent electronic components.

[0042] Further reference Figure 6The substrate 600 includes an electronic component 602 adjacent to an electronic component 605 in direction 1, which is perpendicular to direction 2 where electronic components 604 and 605 extend. Terminals 621 of the electronic component 602 are electrically and / or mechanically connected to conductive pads 623 on the substrate 600 via a solder layer structure identical to the single-layer solder layer structure beneath terminals 642. The process of forming this structure is similar to the method used to form a solder layer beneath terminals 642 and includes the following steps: First, a second solder paste is applied to the conductive pads 623; then, the electronic component 602 is placed on the substrate 600 such that terminals 621 contact the second solder paste applied to the conductive pads 623. Finally, the second solder paste is reflowed to form a strong connection between terminals 621 and conductive pads 623. For the reasons described above, the solder paste beneath adjacent terminals 651 and 621 is unlikely to contact each other and form solder bridges. It is understood that the shape and size of the terminals and conductive pads on structure 600 are for illustrative purposes only. The electronic device 600 can also be configured with terminals or conductive pads of different shapes or sizes.

[0043] Further reference Figure 6 Considering the solder layer structure beneath terminal 651, terminal 681 adjacent to terminal 651 may have the same solder layer structure as the solder layer structure beneath terminal 621 to reduce the risk of solder bridging or short-circuit defects. In some embodiments, each solder layer structure beneath a terminal is different from the corresponding solder layer structure beneath all terminals adjacent to said terminal. Specifically, in some embodiments, terminals 611, 612, 631, 632, 652, 671, 672, 691, and 692 may have the same solder layer structure as the solder layer structure beneath terminal 651, while terminals 622, 641, 642, 661, 662, 681, and 682 may have the same solder layer structure as the solder layer structure beneath terminal 621. It is understood that the distribution of these different solder layer structures beneath these terminals can be implemented in various ways, all of which ensure that the solder layer structure beneath adjacent terminals of different components is similar to the solder layer structure beneath terminals 651 and 621.

[0044] The method for forming the electronic device 600 generally corresponds to the method described above. First, a substrate 600 having a plurality of conductive pads is provided. Next, a first solder paste is applied to a first set of conductive pads on the substrate 600, forming a solder layer structure similar to the solder layer structure below the terminal 651. Then, the first solder paste on the first set of conductive pads is reflowed to form a first solder layer on each of the first set of conductive pads. Afterward, a second solder paste is applied to all the first solder layers and the second set of conductive pads on the substrate 600, forming a solder layer structure similar to the solder layer structure below the terminal 621. Then, a plurality of electronic components are placed on the substrate 600, their terminals contacting the second solder paste on the first solder layers and the second set of conductive pads, respectively. Finally, the second solder paste is reflowed to mount these electronic components onto the substrate 600.

[0045] In some embodiments, a template may be used to apply first and / or second solder paste. The template for applying the first solder paste may have multiple openings corresponding to a first set of conductive pads on the substrate. The template for applying the second solder paste may have openings corresponding to a first set and a second set of conductive pads on the substrate 600, wherein the openings for the first set of conductive pads are smaller than the openings for the second set of conductive pads.

[0046] As described above, compared with conventional solder paste setups, this application reduces the risk of solder bridges or short circuit defects between adjacent electronic components.

[0047] The discussion herein includes numerous illustrative figures illustrating the various parts of an electronic package and how they are formed. For clarity, these figures do not show all aspects of each example component. Any example component and / or method provided herein may share any or all of its characteristics with any or all other components and / or methods provided herein.

[0048] Various embodiments have been described herein with reference to the accompanying drawings. However, it will be apparent that various modifications and changes can be made thereto, and other embodiments can be practiced, without departing from the broad scope of the invention as set forth in the appended claims. Furthermore, other embodiments will be apparent to those skilled in the art upon consideration of the description and practice of one or more embodiments of the invention disclosed herein. Therefore, it is intended that this application and the examples herein be considered exemplary only, and the true scope and spirit of the invention should be indicated by the appended exemplary claims.

Claims

1. A method for forming an electronic package, characterized in that, The method includes: A substrate is provided, wherein the substrate includes a first conductive pad and a second conductive pad, a terminal of a first electronic component is used to be mounted to the first conductive pad, a terminal of a second electronic component is used to be mounted to the second conductive pad, wherein the first conductive pad and the second conductive pad are adjacent to each other. A first solder paste is formed on the first conductive pad; The first solder paste on the first conductive pad is reflowed to form a first solder layer; A second solder paste is formed on the first solder layer and the second conductive pad, respectively; The first electronic component and the second electronic component are placed on the substrate such that the terminals of the first electronic component are in contact with the second solder paste on the first solder layer, and the terminals of the second electronic component are in contact with the second solder paste on the second conductive pad; and The second solder paste is reflowed to mount the first electronic component and the second electronic component onto the substrate.

2. The method according to claim 1, characterized in that, The first solder paste is different from the second solder paste.

3. The method according to claim 1, characterized in that, The first solder paste has a higher melting temperature than the second solder paste.

4. The method according to claim 1, characterized in that, The amount of second solder paste formed on the first solder layer is less than the amount of second solder paste formed on the second conductive pad.

5. The method according to claim 1, characterized in that, The amount of second solder paste formed on the first solder layer is less than the amount of first solder paste formed on the first conductive pad.

6. The method according to claim 1, characterized in that, The formation of the second solder paste includes: A template is placed on the substrate such that a first opening and a second opening of the template are aligned with the first conductive pad and the second conductive pad, respectively, wherein the first opening is smaller than the second opening; and The second solder paste is applied to the first solder layer through the first opening, and to the second conductive pad through the second opening.

7. The method according to claim 6, characterized in that, The template has a recessed portion surrounding the first opening for at least partially accommodating the first solder layer.

8. The method according to claim 1, characterized in that, The first solder paste is selected from the group consisting of Sn5Sb solder and Sn10Sb solder.

9. The method according to claim 1, characterized in that, The second solder paste is SAC305 paste.

10. The method according to claim 1, characterized in that, The substrate includes a third conductive pad, to which a terminal of a third electronic component is mounted. The third conductive pad is adjacent to the first conductive pad in a direction perpendicular to the direction extending along the first and second conductive pads. The method further includes: A second solder paste is formed on the third conductive pad; The third electronic component is placed on the substrate such that the terminals of the third electronic component contact the second solder paste on the third conductive pad; and The second solder paste is reflowed to mount the third electronic component onto the substrate.

11. An electronic package, characterized in that, The electronic package is formed using the method according to claim 1.

12. An electronic device, characterized in that, include: substrate; The first conductive pad and the second conductive pad on the substrate, wherein the first conductive pad is adjacent to the second conductive pad; A first solder layer is formed on the first conductive pad; A second solder layer is formed on the first solder layer and the second conductive pad, respectively; A first electronic component, the terminals of which are mounted on the first conductive pad via the first solder layer and the second solder layer; The second electronic component has its terminals mounted on the second conductive pad via the second solder layer.

13. The electronic device according to claim 12, characterized in that, The first solder layer is formed of a first solder paste, and the second solder layer is formed of a second solder paste that is different from the first solder paste.

14. The electronic device according to claim 13, characterized in that, The first solder paste has a higher melting temperature than the second solder paste.

15. The electronic device according to claim 13, characterized in that, The amount of second solder paste used to form the second solder layer on the first solder layer is less than the amount of second solder paste used to form the second solder layer on the second conductive pad.

16. The electronic device according to claim 13, characterized in that, The amount of second solder paste used to form the second solder layer on the first solder layer is less than the amount of first solder paste used to form the first solder layer on the first conductive pad.

17. The electronic device according to claim 13, characterized in that, The first solder paste is selected from the group consisting of Sn5Sb solder and Sn10Sb solder, which have melting temperatures.

18. The electronic device according to claim 13, characterized in that, The second solder paste is SAC305 paste with a melting temperature.

19. The electronic device according to claim 12, characterized in that, Also includes: A third conductive pad on the substrate, wherein the third conductive pad is adjacent to the first conductive pad in a direction perpendicular to the direction extending along the first and second conductive pads; and The second solder layer is also formed on the third conductive pad, and the electronic device further includes a third electronic component whose terminals are mounted on the third conductive pad via the second solder layer.

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