Surface-mounted substrate and packaging method

Abstract

The invention provides a mounting substrate and a packaging method, the mounting substrate comprises a plurality of mounting units, the mounting units are divided into good units and bad units, the upper surface of each good unit is provided with a bonding pad, and the lower surface of each bad unit is provided with a bonding pad; and the upper surface of the bad unit is provided with a groove which is recessed towards the interior of the surface-mounted substrate at the same position as the bonding pad on the upper surface of the good unit. The upper surface of the defective unit is provided with a groove which sinks towards the interior of the surface-mounted substrate, and when a solder layer is formed on the surface of the surface-mounted substrate in the process of performing component surface-mounting by using the surface-mounted substrate, solder blocks of the solder layer on the upper surface of the defective unit can be distributed in the groove; when a reflow soldering process is executed, the solder blocks only flow in the grooves after being fused and do not overflow to the surface of the plastic package body, so that solder is prevented from forming tin beads or being absorbed by a bonding pad on an area corresponding to the adjacent good unit, and the reliability of the device is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging, and more particularly to a mounting substrate and a packaging method. Background Technology

[0002] As the core carrier of modern electronic packaging, the substrate plays multiple key roles in the packaging structure, providing electrical interconnection, mechanical support, thermal management, and signal integrity assurance for chips and system-in-package (SiP). With the development of semiconductor technology towards high-density, high-performance, and multi-functional integration, the role of the substrate becomes increasingly important.

[0003] After entering the packaging line, the substrate undergoes multiple processes, including copper pillar placement, adapter board soldering, connector assembly, chip mounting, and molding, to form a mounting substrate. The quality of the incoming substrate directly affects the yield of subsequent packaging processes. Therefore, defect detection is required before the packaging process. Defective areas of the substrate will not undergo processes such as copper pillar placement, adapter board soldering, connector assembly, and chip mounting during packaging; only molding will be performed to reduce costs and improve the yield of the packaging structure. After molding, the surface of the mounting substrate corresponding to the defective areas lacks solder pads. This makes it easy for the solder to roll during the solder formation process on the surface of the molded body, resulting in a decrease in device reliability.

[0004] Therefore, how to prevent solder from rolling on the surface of the molding compound and improve the reliability of the device has become one of the key research focuses. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a mounting substrate and a packaging method that can prevent solder from rolling on the surface of the molding compound and improve the reliability of the device.

[0006] To address the aforementioned problems, the present invention provides a mounting substrate comprising a plurality of mounting units, wherein the mounting units are divided into good units and defective units, the upper surface of the good units has pads, and the upper surface of the defective units has grooves corresponding to the pad positions on the upper surface of the good units, which are recessed toward the interior of the mounting substrate.

[0007] In one specific embodiment, the position of the groove corresponds one-to-one with the position of the pad.

[0008] In one specific embodiment, the position of one of the grooves corresponds to the position of a plurality of the pads.

[0009] In one specific embodiment, the position of one of the grooves corresponds to the position of all the pads.

[0010] In one specific embodiment, the sidewall of the groove is stepped.

[0011] In one specific embodiment, the mounting substrate includes: an initial substrate, including defective units and non-defective units, wherein the defective units correspond to the bad units and the non-defective units correspond to the good units; and a molding compound, which covers the initial substrate, wherein the upper surface of the pads at the good units is exposed on the upper surface of the molding compound, and the grooves at the bad units are recessed toward the molding compound.

[0012] In one embodiment, the groove extends through the molding compound to the upper surface of the initial substrate.

[0013] In one specific embodiment, the groove extends into the encapsulation body by a predetermined distance, the predetermined distance being less than the thickness of the encapsulation body.

[0014] In one specific embodiment, the upper surface of the molding compound is flush with the upper surface of the solder pad.

[0015] In one specific embodiment, the upper surface of the molding compound is lower than the upper surface of the solder pad.

[0016] In one specific embodiment, the mounting substrate further includes: a conductive connector, one end of which is disposed on the upper surface of the initial substrate, and the pads are disposed on the other end of the conductive connector; a chip disposed on the upper surface of the initial substrate; and a molding compound covering the conductive connector, the chip, and the pads.

[0017] In one specific embodiment, the chip is flip-chip or upright mounted on the upper surface of the initial substrate.

[0018] In one embodiment, the mounting substrate is divided into a plurality of mounting units by dicing channels.

[0019] This invention also provides a packaging method, comprising: forming a mounting substrate, the mounting substrate including a plurality of mounting units, the mounting units being divided into good units and defective units, the upper surface of the good units having pads, and the upper surface of the defective units having grooves recessed toward the interior of the mounting substrate corresponding to the pads on the upper surface of the good units; forming a solder layer on the upper surface of the mounting substrate, the solder layer including a plurality of solder blocks, the solder blocks being located on the pads in the areas corresponding to the good units, and the solder blocks being located in the grooves in the areas corresponding to the defective units; mounting components and performing a reflow soldering process.

[0020] In one specific embodiment, the position of the groove corresponds one-to-one with the position of the pad.

[0021] In one specific embodiment, the position of one of the grooves corresponds to the position of a plurality of the pads.

[0022] In one specific embodiment, the position of one of the grooves corresponds to the position of all the pads.

[0023] In one specific embodiment, the sidewall of the groove is stepped.

[0024] In one specific embodiment, the size of the groove is larger than the size of the solder block.

[0025] In one specific embodiment, the step of forming a mounting substrate further includes: providing an initial substrate, the initial substrate including defective units and non-defective units, the defective units corresponding to the bad units and the non-defective units corresponding to the good units; disposing conductive connectors, pads, and chips at the non-defective units of the initial substrate, one end of the conductive connector being disposed on the upper surface of the initial substrate and the pad being disposed on the other end of the conductive connector; molding to form a molding compound, the molding compound covering the conductive connectors, the chip, and the pads, the upper surface of the pads being exposed on the upper surface of the molding compound; and forming the groove on the upper surface of the molding compound corresponding to the defective unit.

[0026] In one specific embodiment, the groove is formed using a cutting process.

[0027] In one embodiment, the groove extends through the molding compound to the upper surface of the initial substrate.

[0028] In one specific embodiment, the groove extends into the encapsulation body by a predetermined distance, the predetermined distance being less than the thickness of the encapsulation body.

[0029] In one specific embodiment, the upper surface of the molding compound is flush with the upper surface of the solder pad.

[0030] In one specific embodiment, the upper surface of the molding compound is lower than the upper surface of the solder pad.

[0031] In one specific embodiment, the molding process of forming a molded body further includes: molding to form an initial molding layer, the initial molding layer covering the conductive connector, the chip, and the pads, the upper surface of the pads being covered by the initial molding layer; and thinning the initial molding layer until the upper surface of the pads is exposed.

[0032] In one specific embodiment, the chip is flip-chip or upright mounted on the upper surface of the initial substrate.

[0033] In one specific embodiment, the step of forming a solder layer on the upper surface of the mounting substrate further includes: forming the solder layer on the upper surface of the mounting substrate using a screen printing process.

[0034] In one specific embodiment, the mounting substrate is divided into multiple mounting units by dicing channels, and the packaging method further includes: cutting along the dicing channels to form multiple independent packaging structures.

[0035] In the mounting substrate and packaging method provided in the specific embodiments of the present invention, the pad position on the upper surface of the defective unit corresponding to the pad position on the upper surface of the good unit does not have a pad, but is provided with a groove recessed towards the interior of the mounting substrate. In the process of mounting components using the mounting substrate, when a solder layer is formed on the surface of the mounting substrate, the solder blocks of the solder layer on the upper surface of the defective unit can be distributed in the groove. When performing the reflow soldering process, the solder blocks melt and flow only in the groove, without overflowing to the surface of the molding compound, avoiding the formation of solder balls or absorption by the pads on the area corresponding to the adjacent good unit, thereby improving the reliability of the device.

[0036] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic cross-sectional view of a strip-shaped initial substrate; Figure 2 This is a cross-sectional schematic diagram of a mounting substrate formed by performing a packaging process on the surface of the initial substrate; Figure 3 This is a top view of a mounting substrate formed by performing a packaging process on the surface of the initial substrate; Figure 4 This is a cross-sectional schematic diagram of a solder layer formed on the surface of a mounting substrate. Figure 5 This is a top view of the solder layer formed on the surface of the mounting substrate. Figure 6 This is a cross-sectional schematic diagram of components mounted on the surface of the mounting substrate; Figure 7 This is a cross-sectional schematic diagram of a mounting substrate provided in a specific embodiment of the present invention; Figure 8This is a top view schematic diagram of a mounting substrate provided in a specific embodiment of the present invention; Figure 9 This is a top view schematic diagram of a solder layer disposed on a mounting substrate provided in a specific embodiment of the present invention; Figure 10 This is a cross-sectional schematic diagram of a mounting substrate provided in another specific embodiment of the present invention; Figure 11 This is a cross-sectional schematic diagram of a mounting substrate provided in another specific embodiment of the present invention; Figure 12 This is a cross-sectional schematic diagram of a mounting substrate provided in another specific embodiment of the present invention; Figure 13 This is a top view schematic diagram of a solder layer disposed on a mounting substrate provided in another specific embodiment of the present invention; Figure 14 This is a top view schematic diagram of a mounting substrate provided in another specific embodiment of the present invention; Figure 15 This is a top view schematic diagram of a solder layer disposed on a mounting substrate provided in another specific embodiment of the present invention; Figure 16 This is a schematic diagram of the steps of the encapsulation method provided in a specific embodiment of the present invention; Figure 17 This is a schematic diagram of the initial substrate provided in the packaging method of the present invention; Figure 18 This is a schematic diagram of the packaging method provided by the present invention, in which conductive connectors, pads and chips are provided at the non-defective units of the initial substrate; Figure 19 This is a schematic diagram of the molding compound formed in the packaging method provided by the present invention; Figure 20 This is a schematic diagram of forming a mounting substrate in the packaging method provided by the present invention; Figure 21 This is a schematic diagram of the solder layer formed on the upper surface of the mounting substrate in the packaging method provided by the present invention; Figure 22 This is a schematic diagram of mounting components on the upper surface of the mounting substrate in the packaging method provided by the present invention; Figure 23 This is a schematic diagram of the packaging structure formed after cutting in the packaging method provided by the present invention.

[0039] Explanation of reference numerals in the attached figures: 11 defective units 12 Good Units 100 defective units 110 non-defective elements 20 pads 21 grooves 200 copper pillars 210 chip 30 initial substrates 31 defective units 32 non-defective elements 300 molded body 310 pad 40 Molded Body 400 solder blocks 50 conductive connector 60 chips 600 components 610 solder balls 70 solder blocks 700 defective units 710 Good Unit 730 cutting track 740 initial substrate 741 defective unit 742 non-defective elements 743 Molded Body 750 conductive connector 760 chip 80 components 800 pads 810 Groove 900 solder block. Detailed Implementation

[0040] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Figure 1 This is a schematic cross-sectional view of a strip-shaped initial substrate, such as... Figure 1 As shown, the initial substrate includes multiple units, each unit being used to set structures such as semiconductor devices in subsequent packaging processes. Before performing the packaging process, the initial substrate undergoes defect detection to identify defective and non-defective units. Figure 1 As shown, after defect detection, the units of the initial substrate are divided into defective units 100 and non-defective units 110. Among them, units with defects such as open circuits / short circuits, pad oxidation, dielectric layer delamination, or dimensional deviations are classified as defective units 100.

[0042] Figure 2 This is a cross-sectional schematic diagram of a mounting substrate formed by performing a packaging process on the surface of the initial substrate. Figure 3 This is a top view of a mounting substrate formed by performing a packaging process on the surface of the initial substrate, as shown below. Figure 2 and Figure 3 As shown, in the area corresponding to the non-defective unit 110, copper pillars 200 are installed and chips 210 are mounted on the surface of the initial substrate. In the area corresponding to the defective unit 100, the surface of the initial substrate is not covered by copper pillars 200 or chips 210. After the copper pillars 200 and chips 210 are mounted, a molding process is performed, and a molding compound 300 covers the surface of the initial substrate and encapsulates the copper pillars 200 and chips 210. In the area corresponding to the non-defective unit 110, the surface of the molding compound 300 exposes pads 310 that connect to the chip 210 or the copper pillars 200, etc., which are encapsulated by the molding compound 300. In the area corresponding to the defective unit 100, since the surface of the initial substrate does not have copper pillars 200 and chips 210, the surface of the molding compound 300 does not have the pads 310.

[0043] Figure 4 This is a cross-sectional schematic diagram of a solder layer formed on the surface of a mounting substrate. Figure 5 This is a top view diagram illustrating the formation of a solder layer on the surface of a mounting substrate, such as... Figure 4 and Figure 5 As shown, a solder layer is formed on the surface of the mounting substrate, and solder blocks 400 are distributed across the entire surface of the molding compound 300 of the mounting substrate. Before forming the solder layer on the surface of the mounting substrate, in order to ensure the consistency of the distribution of the solder blocks 400 on each unit of the mounting substrate, a distribution rule for the solder blocks 400 is predetermined. When forming the solder layer on the surface of the mounting substrate, the solder blocks 400 are distributed according to the predetermined rule. Due to the uncertainty of the distribution of the area corresponding to the defective unit 100 on the mounting substrate, the area corresponding to the defective unit 100 cannot be excluded by the predetermined rule. Therefore, the solder blocks 400 are evenly distributed in each unit according to the predetermined rule. That is to say, solder blocks 400 are present in both the area corresponding to the non-defective unit 110 and the area corresponding to the defective unit 100.

[0044] Figure 6 This is a cross-sectional schematic diagram of components mounted on the surface of the mounting substrate, as shown below. Figure 6As shown, components 600 are mounted on the surface of the molding compound 300 on the mounting substrate, and a reflow soldering process is performed. The components 600 are mounted in the area corresponding to the non-defective unit 110. Since the area corresponding to the defective unit 100 does not have pads 310 and unmounted components 600, during the reflow soldering process, the solder slab 400 in this area, after melting, tends to roll outwards on the surface of the molding compound 300, forming solder balls 610. These solder balls 610 may get stuck under the components 600, potentially causing a short circuit or even product failure. Alternatively, the solder slab 400, after melting, may be absorbed by the pads 310 in the area corresponding to the adjacent non-defective unit 110, resulting in poor component soldering and reducing component reliability.

[0045] In view of the above reasons, the present invention provides a mounting substrate and a packaging method that can prevent solder from rolling on the surface of the molding compound, thereby preventing the solder from forming solder balls or being absorbed by the pads on the area corresponding to the adjacent non-defective unit, thus improving the reliability of the device.

[0046] The specific embodiments of the mounting substrate provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0047] Figure 7 This is a cross-sectional schematic diagram of a mounting substrate provided in a specific embodiment of the present invention. Figure 8 This is a top view schematic diagram of a mounting substrate provided in a specific embodiment of the present invention. Figure 9 This is a top view schematic diagram of a solder layer disposed on a mounting substrate according to a specific embodiment of the present invention. Please refer to [the diagram]. Figure 7 , Figure 8 and Figure 9 The mounting substrate includes multiple mounting units, which are divided into good units 710 and bad units 700. The upper surface of the good unit 710 has a pad 800, and the upper surface of the bad unit 700 has a groove 810 that is recessed toward the interior of the mounting substrate at the position of the pad 800 on the upper surface of the good unit 710.

[0048] In the mounting substrate provided in the specific embodiment of the present invention, the position of the pad 800 on the upper surface of the defective unit 700 corresponding to the upper surface of the good unit 710 does not have a pad 800, but is provided with a groove 810 recessed towards the interior of the mounting substrate. In the process of mounting components using the mounting substrate, when a solder layer is formed on the surface of the mounting substrate, the solder blocks 900 of the solder layer on the upper surface of the defective unit 700 can be distributed in the groove 810. When performing the reflow soldering process, the solder blocks 900 melt and flow only in the groove 810, without overflowing onto the surface of the molding compound 743, avoiding the formation of solder balls or absorption by the pads 800 on the area corresponding to the adjacent good unit 710, thereby improving the reliability of the device.

[0049] In one embodiment, the mounting substrate is divided into multiple mounting units by dicing channels 730. The surface of the mounting substrate has dicing channels 730 arranged in a grid pattern along its surface extension direction. Each dicing channel 730 includes multiple intersecting transverse cutting lines and multiple longitudinal cutting lines, arranged orthogonally at predetermined intervals, thereby dividing the mounting substrate into multiple mounting units arranged in an array. Further, in some embodiments, the mounting units are rectangular or square in shape. Further, in some embodiments, alignment marks and / or test patterns are provided within the dicing channels 730 between adjacent mounting units for precise positioning and process monitoring during the cutting process.

[0050] The mounting unit is divided into good units 710 and defective units 700. The structure of the upper surface of the good unit 710 and the defective unit 700 is different. Specifically, the upper surface of the good unit 710 has pads 800 for mounting to devices with solder; the upper surface of the defective unit 700 does not have pads 800 at the position corresponding to the pads 800 on the upper surface of the good unit 710, but instead has grooves 810 recessed towards the interior of the mounting substrate, which are used to accommodate solder that is not connected to the device.

[0051] In one specific embodiment, the mounting substrate includes an initial substrate 740, and the good units 710 and defective units 700 are determined based on the initial substrate 740. Specifically, the initial substrate 740 includes a plurality of units, each unit corresponding to a mounting unit of the mounting substrate. Before performing the packaging process, the initial substrate 740 is subjected to defect detection to determine defective units 741 and non-defective units 742 of the initial substrate 740. Units with defects such as open circuits / short circuits, pad oxidation, dielectric layer delamination, or dimensional deviations are classified as defective units 741. The defective units 741 correspond to the defective units 700 of the mounting substrate, and the non-defective units 742 correspond to the good units 710 of the mounting substrate.

[0052] The initial substrate 740 can be made of existing ceramic substrates, lead frames, multilayer substrates, MIS (Molded Interconnect System) plastic-encapsulated interconnect substrates, or redistribution stacks, etc. These substrate materials and technologies each have their own characteristics: ceramic substrates have excellent thermal conductivity and mechanical strength, suitable for high-power and high-reliability applications; lead frames have lower costs, suitable for traditional packaging requirements; multilayer substrates achieve high-density interconnection through multi-layer wiring, suitable for complex circuit designs; MIS plastic-encapsulated interconnect substrates combine injection molding and interconnection technologies, offering advantages in high integration and low cost; redistribution stacks achieve higher integration density and performance optimization through vertical stacking and redistribution technology. The material selection and structural design of the initial substrate 740 can be adjusted according to the needs of specific application scenarios. For example, low-dielectric-constant materials can be used in high-frequency applications to reduce signal loss, or high-temperature resistant materials can be used in high-temperature environments to improve reliability.

[0053] In one specific embodiment, the mounting substrate further includes a molding compound 743. The molding compound 743 covers the initial substrate 740. The molding compound 743 is made of thermosetting materials such as epoxy resin and uniformly covers the entire surface of the initial substrate 740 to form a reliable physical protective layer. The molding compound 743 has good mechanical strength, thermal stability, and moisture resistance, effectively protecting the internal structure from the influence of the external environment (such as moisture, dust, mechanical stress, etc.), while providing structural support for subsequent cutting, testing, and assembly processes. In addition, the thickness and shape of the molding compound 743 can be precisely controlled according to the package type (such as QFN, BGA, etc.) to meet the requirements of different application scenarios for package size and heat dissipation performance.

[0054] In one specific embodiment, the mounting substrate further includes a conductive connector 750 and a chip 760. Since the defective unit 741 of the initial substrate 740 is removed as a discarded structure in the subsequent mounting substrate cutting process, to save costs, the conductive connector 750 and the chip 760 are not disposed at the defective unit 741 of the initial substrate 740; instead, the conductive connector 750 and the chip 760 are only disposed at the non-defective unit 742 of the initial substrate 740.

[0055] One end of the conductive connector 750 is disposed on the upper surface of the initial substrate 740, and the pad 800 is disposed on the other end of the conductive connector 750. The conductive connector 750, as a key component connecting the initial substrate 740 and the pad 800, has one end fixedly connected to the upper surface of the initial substrate 740. This can be achieved through processes such as welding, bonding, or pressing to ensure reliable fixation and the stability of the electrical connection and the robustness of the mechanical connection. The other end of the conductive connector 750 supports the pad 800, which serves as the interface component for the electrical connection. The pad 800 achieves electrical conductivity with the conductive connector 750 through methods such as electroplating, welding, or conductive adhesive bonding.

[0056] In some specific embodiments, the conductive connector 750 can be selected in various ways according to actual application needs and product design requirements. When there are high requirements for vertical electrical connections and a certain mechanical support strength is needed, the conductive connector 750 can take the form of a conductive post. The conductive post can be made of metal materials with good conductivity, such as copper, gold, or silver, or their alloys, and its shape can be regular or irregular, such as cylindrical or prismatic. If a large-area planar electrical connection is required, or in a scenario with a relatively compact spatial layout, the conductive connector 750 can be a conductive connection plate. The conductive connection plate can take the form of a flexible circuit board (FPC) or a rigid circuit board (PCB), and the conductive connection plate can be soldered onto the initial substrate 740 using surface mount technology (SMT). Furthermore, when a detachable or replaceable electrical connection is required, the conductive connector 750 can also be a conductive connector, which includes a plug and a socket. The plug is connected to the circuitry on the initial substrate 740, and the socket is connected to the pad 800. Electrical connection is achieved through a plug-in connection. The conductive connector can be of various types, such as board-to-board connectors and wire-to-board connectors, to meet the needs of different application scenarios. In this specific embodiment, the conductive connector 750 is a copper pillar.

[0057] The chip 760, as a key component for realizing specific functions, can be disposed on the upper surface of the initial substrate 740 in a flip-chip or upright manner according to different design requirements and application scenarios.

[0058] When the chip 760 is configured using a flip-chip method, specifically, the active surface of the chip 760 faces the upper surface of the initial substrate 740. Multiple conductive bumps are formed on the active surface of the chip 760, and corresponding pads are provided on the upper surface of the initial substrate 740 at the positions of the conductive bumps of the chip 760. The conductive bumps and pads form a strong electrical and mechanical connection. The flip-chip configuration offers advantages such as shortening the signal transmission path, reducing parasitic parameters, and improving chip heat dissipation performance, making it particularly suitable for applications with high requirements for signal transmission speed and heat dissipation. Figure 7 In the specific embodiment shown, the chip 760 is disposed on the upper surface of the initial substrate 740 in a flip-chip manner.

[0059] When the chip 760 is mounted in a forward-facing configuration, the active surface of the chip 760 faces away from the upper surface of the initial substrate 740. Multiple electrodes are disposed on the active surface of the chip 760, and these electrodes are electrically connected to corresponding circuits on the initial substrate 740 via a bonding process. This forward-facing configuration offers advantages such as mature technology, lower cost, and ease of testing and maintenance, making it suitable for applications with strict cost control and relatively lower requirements for heat dissipation and signal transmission speed.

[0060] Regardless of whether the chip 760 is flip-chip or upright-mounted, appropriate auxiliary processes and materials can be used to further improve the reliability and stability of the connection during the connection process between the chip 760 and the initial substrate 740. For example, an underfill adhesive can be filled between the chip 760 and the initial substrate 740. This underfill adhesive can enhance the mechanical connection strength between the chip 760 and the initial substrate 740 and alleviate the impact of thermal stress on the connection area. At the same time, positioning structures, such as positioning grooves and positioning holes, can be provided on the initial substrate 740 to ensure the precise alignment of the chip 760 during installation. In addition, to ensure the normal operation of the chip 760, corresponding circuit structures, such as power supply circuits, signal transmission circuits, and grounding circuits, can also be provided on the initial substrate 740. These circuit structures work together with the chip 760 to realize the function of the entire system.

[0061] In some specific embodiments, the molding compound 743 encapsulates the conductive connector 750, the chip 760, and the pads 800. The molding compound 743 forms a reliable physical protective layer, effectively protecting the conductive connector 750, the chip 760, and the pads 800 from the influence of the external environment (such as moisture, dust, mechanical stress, etc.), while providing structural support for subsequent cutting, testing, and assembly processes.

[0062] The upper surface of the pads 800 of the good unit 710 is exposed to the upper surface of the molding compound 743, facilitating subsequent electrical connections. For example, when mounting components onto the mounting substrate, electrical conduction can be achieved directly through the exposed pads 800. To ensure good electrical performance and solderability of the exposed pads 800, their surfaces can be specially treated, such as by nickel plating or gold plating. Simultaneously, during the molding process, appropriate measures need to be taken to ensure that the upper surface of the pads 800 is accurately exposed, avoiding coverage or contamination by the molding compound material.

[0063] In some specific embodiments, the upper surface of the molding compound 743 is flush with the upper surface of the pad 800. The molding compound 743 can comprehensively and seamlessly encapsulate and cover the pad 800, effectively resisting the erosion and damage to the pad 800 from external environmental factors (such as moisture, dust, corrosive gases, etc.), thereby achieving maximum physical protection for the pad 800 and significantly improving the environmental tolerance of the pad 800. Furthermore, since the upper surfaces of the two are flush, the molding compound 743 can provide uniform and stable mechanical support for the pad 800, effectively dispersing external stress during subsequent processes such as device mounting and soldering, avoiding deformation and cracking of the pad 800 due to uneven stress, ensuring that the pad 800 maintains structural integrity and electrical performance stability under complex operating conditions, thus providing a solid guarantee for the reliable operation of the entire electronic packaging assembly and greatly improving the long-term reliability and service life of the product.

[0064] In other specific embodiments, through innovative design of the structural layout of the molding compound 743 and the pad 800, the upper surface of the molding compound 743 is lower than the upper surface of the pad 800. This structure allows for precise control of the filling amount and molding height of the molding compound during the molding process, based on pre-set mold structure and process parameters. The differentiated height design effectively prevents excessive coverage of the pad 800 surface by the molding compound, thereby reducing subsequent secondary processing steps for the pad 800 and improving production efficiency. Simultaneously, this structure gives the pad 800 a certain degree of protrusion, making it more operable and adaptable in the electronic device mounting process. During surface mount technology (SMT), the protruding pad 800 can more easily achieve precise alignment and soldering with the pins or solder terminals of the electronic device, helping to improve soldering accuracy and yield. Meanwhile, the lower structure of the molding compound 743 compared to the solder pad 800 creates a natural buffer space. During the soldering process, this effectively mitigates the impact of temperature changes, mechanical stress, and other factors on the connection between the solder pad 800 and the electronic device, reducing the risk of solder joint failure. Furthermore, this structure can also reduce the adverse effects of the difference in thermal expansion coefficients between the molding compound and the solder pad 800, avoiding solder joint cracking or detachment caused by inconsistent expansion and contraction. This further enhances the reliability and stability of the electronic packaging assembly, meeting the high-performance and long-life requirements of electronic devices in various application scenarios.

[0065] The groove 810 of the defective unit 700 is recessed into the molding compound 743. The groove 810 can be formed on the surface of the molding compound 743 through a cutting process. Specifically, the cutting process can be flexibly selected according to the material properties of the molding compound 743, product precision requirements, and other actual conditions, including but not limited to laser cutting, plasma cutting, and mechanical cutting.

[0066] In a specific embodiment of the mounting substrate of the present invention, the groove 810 serves as a special structural design for the defective unit 700, playing a crucial role in solder control during the device mounting process. During the process of forming a solder layer on the surface of the mounting substrate, solder blocks 900 are formed on the upper surface of the mounting substrate using selective solder paste printing, spray dispensing, or screen printing. The solder blocks 900 are positioned on the upper surface of the defective unit 700, corresponding to the groove 810, allowing them to be distributed within the groove 810. During the reflow soldering process, the melted solder blocks 900 flow only within the groove 810, without overflowing onto the surface of the molding compound 743. This prevents the solder from forming solder balls or being absorbed by the pads 800 in the area corresponding to the adjacent good unit 710, thus improving device reliability.

[0067] In some specific embodiments, to further ensure the controllability of the solder block 900 during the reflow soldering process, the size of the groove 810 is larger than the size of the solder block 900. Specifically, the geometrical parameters of the groove 810, including but not limited to length, width, and depth, can be precisely designed based on the volume, shape, and reflow soldering process characteristics of the solder block 900. In some specific embodiments, the dimensions of the groove 810 in both the length and width directions are larger than the dimensions of the solder block 900 in the corresponding directions, with a preset dimensional margin. This margin value is optimized and determined through thermodynamic simulation and process experiments based on factors such as the thermal expansion coefficient of the solder, surface tension, and temperature gradient during the reflow soldering process, to ensure that the solder block 900 remains confined within the groove 810 after complete melting. In one specific embodiment, in the depth direction, the depth of the groove 810 is greater than the height of the solder block 900, and after the solder block 900 is placed in the groove 810, a preset distance is maintained between the upper surface of the solder block 900 and the surface of the molding compound 743 to form an effective physical barrier, further restricting the flow range of the solder in the groove 810.

[0068] In one specific embodiment, the groove 810 extends into the molding compound 743 by a predetermined distance, which is less than the thickness of the molding compound 743. That is, the groove 810 does not penetrate the molding compound 743 to the upper surface of the initial substrate 740. The groove 810 is designed as a non-penetrating structure. Specifically, the groove 810 starts from the upper surface of the molding compound 743 and extends into the interior of the molding compound 743 in a direction perpendicular to the upper surface of the molding compound 743, reaching a predetermined depth. This predetermined distance is less than the overall thickness of the molding compound 743, ensuring that a certain thickness of the molding compound 743 remains between the bottom of the groove 810 and the upper surface of the initial substrate 740. This non-through groove 810 design, on the one hand, by controlling the groove 810 at a specific depth inside the molding compound 743, can effectively accommodate and constrain the solder without damaging the overall structural integrity of the initial substrate 740 and the molding compound 743; on the other hand, the retained molding compound 743 can serve as a buffer and isolation medium, preventing excessive solder penetration from affecting the performance of the initial substrate 740, and appropriately constraining the flow range of the solder during the welding process, avoiding solder deviation and overflow due to uncontrolled flow. Thus, while ensuring the stability of the welding process, it effectively improves the reliability of the packaging structure, reduces product quality risks caused by abnormal solder flow, and meets the requirements of high-precision electronic packaging processes.

[0069] Figure 10 This is a cross-sectional schematic diagram of a mounting substrate provided in another specific embodiment of the present invention, as shown below. Figure 10As shown, in another specific embodiment, the groove 810 penetrates the molding compound 743 to the upper surface of the initial substrate 740. That is, the groove 810 adopts a through-type design, extending downwards from the top surface of the molding compound 743 until the upper surface of the initial substrate 740 is exposed. Specifically, in the specific area where the groove 810 is intended to be provided, the molding compound 743 covering the upper surface of the initial substrate 740 is completely removed through a precise processing technique, so that the upper surface of the initial substrate 740 is completely exposed. On the one hand, by removing the molding compound 743, the depth of the groove 810 is significantly increased, which can accommodate more solder compared to the conventional non-penetrating groove 810 structure. On the other hand, the deeper groove 810 forms a more effective physical constraint boundary, which can further precisely limit the flow range of solder within the groove 810, effectively avoiding problems such as solder overflow and diffusion to unexpected areas in subsequent processes. This significantly improves the controllability and consistency of solder distribution, ensures the stability and reliability of the welding process, and provides a strong guarantee for the high-precision mounting and reliable connection of subsequent electronic devices, effectively reducing the risk of product quality defects caused by uncontrolled solder flow.

[0070] In some specific embodiments, the sidewall structure of the groove 810 can be varied. Depending on different process requirements and functional considerations, the sidewall of the groove 810 can be a vertical sidewall or a stepped sidewall. Both structural forms have unique technical advantages and application scenarios.

[0071] For example, in one specific implementation, such as Figure 7 As shown, the sidewalls of the groove 810 are vertical. From the opening to the bottom of the groove 810, the sidewalls of the groove 810 are perpendicular to the surface of the mounting substrate, and the groove 810 forms a regular cuboid or cube spatial structure. This structure can provide a relatively regular and unobstructed placement space for solder.

[0072] For example, Figure 11This is a cross-sectional schematic diagram of a mounting substrate provided in another specific embodiment of the present invention. In this embodiment, the sidewall of the groove 810 is stepped, that is, the sidewall of the groove 810 is a stepped sidewall. The stepped sidewall presents a single or multiple stepped structure, composed of one or more stepped surfaces of different heights and widths, forming a unique layered spatial form. By setting the steps, multiple constraint areas of different heights can be constructed inside the groove 810. During the solder melting process, the stepped structure can effectively guide and restrict the flow path of the solder, allowing the solder to accumulate layer by layer on different stepped surfaces, thereby achieving precise control of the solder. In addition, the stepped sidewall can also increase the contact area between the sidewall of the groove 810 and the solder to a certain extent, enhance the adhesion between the solder and the sidewall of the groove 810, improve the fixing effect of the solder in the groove 810, effectively prevent the solder from overflowing onto the surface of the molding compound 743, and significantly improve the applicability and reliability of the mounting substrate.

[0073] In some specific embodiments, the position of the groove 810 is not limited to a single mode, but can present a variety of configuration forms according to different manufacturing process requirements, welding precision requirements, and product functional characteristics. The position of the groove 810 may include: the position of the groove 810 corresponds one-to-one with the position of the pad 800; the position of one groove 810 corresponds to the position of all the pads 800; the position of one groove 810 corresponds to the position of multiple pads 800.

[0074] Specifically, such as Figure 8 As shown, in this specific embodiment, the positions of the grooves 810 and the pads 800 correspond one-to-one. The grooves 810 are small-sized grooves, exhibiting a precise and corresponding positional relationship with the pads 800. That is, in the overall structural layout of the mounting substrate, the distribution of the grooves 810 in the defective unit 700 area has a strict one-to-one correspondence with the distribution of the pads 800 in the good unit 710 area. This correspondence ensures the precise implementation and functional realization of subsequent solder layer formation processes on the mounting substrate surface. Specifically, in this specific embodiment, the positions of the grooves 810 in the defective unit 700 and the pads 800 in the good unit 710 correspond one-to-one. Therefore, when forming the solder layer on the mounting substrate surface, please refer to... Figure 9 At the good unit 710, a solder block 900 is provided on a solder pad 800, and at the bad unit 700, a solder block 900 is provided in a groove 810.

[0075] Figure 12This is a cross-sectional schematic diagram of a mounting substrate provided in another specific embodiment of the present invention. In this embodiment, the position of one groove 810 corresponds to the position of all the pads 800, that is, the groove 810 is a large-sized groove. In the structural layout of the entire mounting substrate, there is only one groove 810 in the area where the defective unit 700 is located. The positional distribution of the groove 810 in the area of ​​the defective unit 700 corresponds to the positional distribution of the pads 800 in the area of ​​the good unit 710. The large-sized groove, with its ample space volume and reasonable positional layout, can reliably ensure that the solder block 900 can smoothly fall into the groove 810 during the subsequent process steps of forming a solder layer on the surface of the mounting substrate. Specifically, in this embodiment, the position of one groove 810 in the defective unit 700 corresponds to the position of all the pads 800 in the good unit 710. Therefore, when forming a solder layer on the surface of the mounting substrate, please refer to... Figure 13 This is a top view schematic diagram of a solder layer disposed on a mounting substrate according to another specific embodiment of the present invention. At the good unit 710, a solder block 900 is disposed on a solder pad 800. At the bad unit 700, all the solder blocks 900 are disposed within a groove 810. Compared to conventionally sized grooves, this larger groove provides sufficient accommodating space, effectively avoiding the problem that the solder blocks 900 cannot be disposed within the groove 810 due to their large size or deviations during the filling process.

[0076] Figure 14 This is a top view schematic diagram of a mounting substrate provided in another specific embodiment of the present invention. In this specific embodiment, the position of one groove 810 corresponds to the position of multiple pads 800, that is, the groove 810 is a medium-sized groove. In the structural layout of the entire mounting substrate, the area where the defective unit 700 is located has two or more grooves 810, and the positional distribution of one groove 810 in the area of ​​the defective unit 700 corresponds to the positional distribution of two or more pads 800 in the area of ​​the good unit 710. Specifically, in this specific embodiment, as... Figure 14 As shown, the position of one of the grooves 810 at the defective unit 700 corresponds to the position of two of the solder pads 800 at the good unit 710. Therefore, when forming the solder layer on the surface of the mounting substrate, please refer to... Figure 15This is a top view schematic diagram of a solder layer being disposed on a mounting substrate according to another specific embodiment of the present invention. At the good unit 710, a solder block 900 is disposed on a solder pad 800, and at the bad unit 700, two solder blocks 900 are disposed within a groove 810. Compared to small-sized grooves, medium-sized grooves have a larger volume, providing ample accommodating area for the solder blocks 900, reliably ensuring that the solder blocks 900 can smoothly fall into the groove 810 during subsequent solder layer formation processes on the surface of the mounting substrate. Compared to large-sized grooves, medium-sized grooves occupy a smaller area on the surface of the molding compound 743, ensuring the overall structural integrity of the molding compound 743 and further guaranteeing the support performance of the molding compound 743 for the entire mounting substrate.

[0077] The mounting substrate provided in the specific embodiments of the present invention utilizes the groove 810 to prevent solder from rolling on the surface of the molding compound 743, thereby preventing the solder from forming solder balls or being absorbed by the pads 800 on the area corresponding to the adjacent non-defective unit 742, thus improving the reliability of the device.

[0078] Based on the same inventive concept, this invention also provides a packaging method in its specific embodiments. Figure 16 This is a schematic diagram illustrating the steps of a packaging method provided in a specific embodiment of the present invention. Please refer to [link / reference]. Figure 16 The packaging method includes: step S160, forming a mounting substrate, the mounting substrate including multiple mounting units, the mounting units being divided into good units and defective units, the upper surface of the good unit having pads, and the upper surface of the defective unit having grooves recessed toward the interior of the mounting substrate corresponding to the pads on the upper surface of the good unit; step S161, forming a solder layer on the upper surface of the mounting substrate, the solder layer including multiple solder blocks, the solder blocks being located on the pads in the area corresponding to the good unit, and the solder blocks being located in the grooves in the area corresponding to the defective unit; step S162, mounting components and performing a reflow soldering process.

[0079] In the packaging method provided by the specific embodiments of the present invention, the position of the pad on the upper surface of the defective unit corresponding to the pad on the upper surface of the good unit of the mounting substrate does not have a pad, but is provided with a groove recessed towards the interior of the mounting substrate. In the process of mounting components using the mounting substrate, when a solder layer is formed on the surface of the mounting substrate, the solder blocks of the solder layer can be distributed in the groove on the upper surface of the defective unit. When performing the reflow soldering process, the solder blocks melt and flow only in the groove, without overflowing to the surface of the molding compound, avoiding the formation of solder balls or absorption by the pads on the area corresponding to the adjacent good unit, thereby improving the reliability of the device.

[0080] The following is combined with Figures 17-23 The specific implementation methods of the packaging method provided by the present invention will be described in detail.

[0081] Figure 20 This is a schematic diagram of forming a mounting substrate in the packaging method provided by the present invention. Please refer to [link / reference]. Figure 16 and Figure 20 Step S160: A mounting substrate is formed. The mounting substrate includes multiple mounting units, which are divided into good units 12 and defective units 11. The upper surface of the good unit 12 has pads 20, and the upper surface of the defective unit 11 has a groove 21 recessed towards the interior of the mounting substrate at the same position as the pads 20 on the upper surface of the good unit 12. The structure of the mounting substrate can be referred to... Figures 7-15 The structure shown and its related description.

[0082] In one specific embodiment, the step of forming the mounting substrate further includes: Figure 17 This is a schematic diagram of the initial substrate 30 provided in the packaging method of the present invention. Please refer to [link / reference]. Figure 17 An initial substrate 30 is provided, the initial substrate 30 including defective units 31 and non-defective units 32, the defective units 31 corresponding to the defective units 11, and the non-defective units 32 corresponding to the good units 12.

[0083] In one specific embodiment, before performing the packaging process, the initial substrate 30 undergoes defect detection to identify the defective units 31 and the non-defective units 32. The defect detection methods include, but are not limited to, optical detection, electron microscopy, and electrical performance testing. After defect detection, the defective units 31 or the non-defective units 32 can be marked to effectively distinguish them, thus providing a reliable basis for differentiated processing in subsequent packaging processes. The initial substrate 30 includes multiple units, wherein units with defects such as open / short circuits, pad oxidation, dielectric layer delamination, or dimensional deviations are designated as defective units 31.

[0084] Figure 18 This is a schematic diagram illustrating the arrangement of conductive connectors 50, pads, and chips 60 at the non-defective unit 32 of the initial substrate in the packaging method provided by the present invention. Please refer to [link / reference]. Figure 18A conductive connector 50, a pad 20, and a chip 60 are provided at the non-defective unit 32 of the initial substrate 30. One end of the conductive connector 50 is disposed on the upper surface of the initial substrate 30, and the pad 20 is disposed at the other end of the conductive connector 50. The conductive connector 50, the pad 20, and the chip 60 are not provided at the defective unit 31 of the initial substrate 30.

[0085] One end of the conductive connector 50 is fixedly connected to the upper surface of the initial substrate 30. This can be achieved through processes such as welding, bonding, or pressing to ensure reliable fixation and guarantee the stability of the electrical connection and the robustness of the mechanical connection. In one specific embodiment, the conductive connector 50 is a conductive post, formed on the upper surface of the initial substrate 30 through processes such as electroplating or chemical vapor deposition. In another specific embodiment, the conductive connector 50 is a conductive connection plate, which can be soldered to the initial substrate 30 using surface mount technology (SMT). In yet another specific embodiment, the conductive connector 50 can also be a conductive connector, comprising a plug and a socket. The plug is connected to the circuitry on the initial substrate 30, and the socket is connected to the pad 20, achieving electrical connection through a plug-in connection. In this specific embodiment, the conductive connector 50 is a copper post.

[0086] The other end of the conductive connector 50 is used to support the solder pad 20. The solder pad 20 serves as an interface component for electrical connection and achieves electrical conductivity with the conductive connector 50 through electroplating, welding, conductive adhesive connection, or other methods. In some specific embodiments, the solder pad 20 can be integrally formed with the conductive post in the same step.

[0087] Depending on the design requirements, the chip 60 can be mounted flip-flop or upright on the upper surface of the initial substrate 30. The mounting method of the chip 60 on the upper surface of the initial substrate 30 can be flexibly selected as flip-flop or upright according to different design requirements, and the two mounting methods have significant differences in electrical connection, mechanical structure, and process implementation.

[0088] When using the inverted configuration, such as Figure 18As shown in the structure, the active surface of the chip 60 is pre-formed with an array of conductive bumps made of metal materials such as gold, tin, and copper through processes such as electroplating and chemical deposition. Corresponding pads are provided on the upper surface of the initial substrate 30 at the positions of the conductive bumps of the chip 60. These pads are precisely prepared using processes such as photolithography and etching, and their surfaces can be specially treated to improve soldering performance, such as by nickel plating or gold plating. During the flip-chip process, the conductive bumps of the chip 60 are precisely aligned with the pads of the initial substrate 30, and then a reflow soldering process is used to achieve metallurgical bonding between the conductive bumps and the pads under high temperature, forming a low-resistance, high-reliability electrical connection.

[0089] When mounted in the upright position, the active surface of the chip 60 faces away from the upper surface of the initial substrate 30, and electrodes are formed on the active surface. These electrodes are electrically connected to corresponding circuits on the initial substrate 30 via a bonding process. Bonding processes include, but are not limited to, wire bonding and automatic tape bonding. Taking wire bonding as an example, metal wires, such as gold or aluminum wires, are typically used to connect the electrodes of the chip 60 to the circuits on the initial substrate 30. During the bonding process, precise control of bonding parameters, such as temperature, pressure, and ultrasonic energy, ensures a reliable electrical and mechanical connection between the metal wires, electrodes, and circuits.

[0090] In some specific embodiments, the conductive connector 50 and the pads can be formed before or after the chip 60 is formed. In one specific embodiment, after flip-chip bonding the chip 60, the method further includes filling the space between the chip 60 and the initial substrate 30 with underfill adhesive to enhance the mechanical connection strength between the chip 60 and the initial substrate 30 and mitigate the impact of thermal stress on the connection site.

[0091] Figure 19 This is a schematic diagram of the formation of the molding compound 40 in the encapsulation method provided by the present invention. Please refer to [link / reference]. Figure 19 The substrate is encapsulated to form a molded body 40, which encapsulates the conductive connector 50, the chip 60, and the pads 20, with the upper surface of the pads 20 exposed on the upper surface of the molded body 40. In one specific embodiment, the molded body 40 is formed by injection molding using a thermosetting material such as epoxy resin, uniformly covering the entire surface of the initial substrate 30.

[0092] The upper surface of the pad 20 is exposed on the upper surface of the molding compound 40. In one specific embodiment, the step of forming the molding compound 40 further includes: molding to form an initial molding layer, the initial molding layer covering the conductive connector 50, the chip 60, and the pad 20, the upper surface of the pad 20 being covered by the initial molding layer; thinning the initial molding layer until the upper surface of the pad 20 is exposed, the upper surface of the molding compound 40 being flush with the upper surface of the pad 20. In one specific embodiment, the upper surface of the molding compound 40 may also be lower than the upper surface of the pad 20. In the step of forming the molding compound 40, the upper surface of the molding compound 40 may be lower than the upper surface of the pad 20 by removing a portion of the molding compound 40.

[0093] Please see Figure 20 The groove 21 is formed on the upper surface of the molding compound 40 corresponding to the defective unit 31. In this step, the groove 21 is not formed on the upper surface of the molding compound 40 corresponding to the non-defective unit 32. The groove 21 is positioned corresponding to the position of the pad 20 on the surface of the non-defective unit 32.

[0094] In one specific embodiment, the groove 21 is formed using a cutting process. The cutting process can be flexibly selected according to the material properties of the encapsulated body 40, product precision requirements, and other actual conditions, including but not limited to laser cutting, plasma cutting, and mechanical cutting.

[0095] Laser cutting involves focusing a high-energy-density laser beam onto a predetermined position on the surface of the molding compound 40. The laser's thermal effect causes the molding compound 40 material to melt and vaporize instantaneously, achieving cutting. Laser cutting offers advantages such as high precision, good cut quality, and a small heat-affected zone. Plasma cutting utilizes the heat of a high-temperature plasma arc to locally melt and evaporate the molding compound 40 material, forming a cut under the action of a high-speed plasma stream. Mechanical cutting technology uses cutting tools mounted on equipment, such as high-speed rotating diamond or carbide blades, to cut the molding compound 40. In one specific embodiment, before cutting the molding compound 40, the defective unit 11 is accurately identified and located using a visual recognition system and coordinate positioning system to ensure the accuracy of the cutting position. Simultaneously, after cutting, the dimensions, shape, and surface quality of the groove 21 need to be inspected using equipment such as optical microscopes and 3D scanners to ensure that the groove 21 meets design requirements and satisfies the subsequent product's use and performance needs.

[0096] In one specific embodiment, the groove 21 extends through the molding compound 40 to the upper surface of the initial substrate 30. For example... Figure 10As shown, the groove 21 adopts a through-type design, which extends downward from the top surface of the molding compound 40 until the upper surface of the initial substrate 30 is exposed.

[0097] In one specific embodiment, the groove 21 extends within the molding compound 40 by a predetermined distance, the predetermined distance being less than the thickness of the molding compound 40. For example... Figure 20 As shown, the groove 21 does not penetrate the molding compound 40 to the upper surface of the initial substrate 30, and the groove 21 adopts a non-penetrating design.

[0098] The position of the groove 21 can be configured in various ways depending on different manufacturing process requirements, welding precision requirements, and product functional characteristics. The position of the groove 21 can include: the position of the groove 21 corresponds one-to-one with the position of the pad 20; the position of one groove 21 corresponds to the position of all the pads 20; or the position of one groove 21 corresponds to the position of multiple pads 20.

[0099] In some specific embodiments, the sidewall structure of the groove 21 can be a vertical sidewall, depending on different process requirements and functional considerations, such as... Figure 20 As shown; it can also be a stepped sidewall, such as Figure 11 As shown, both structural forms possess unique technical advantages and application scenarios.

[0100] After forming the mounting substrate, the packaging method further includes the following steps: Figure 21 This is a schematic diagram illustrating the formation of a solder layer on the upper surface of the mounting substrate in the packaging method provided by this invention. Please refer to [link / reference]. Figure 16 and Figure 21 In step S161, a solder layer is formed on the upper surface of the mounting substrate. The solder layer includes a plurality of solder blocks 70. In the area corresponding to the good unit 12, the solder blocks 70 are located on the pad 20, and in the area corresponding to the bad unit 11, the solder blocks 70 are located in the groove 21.

[0101] In one specific embodiment, the solder layer can be formed by selective solder paste printing, jet dispensing, or screen printing. For example, in one specific embodiment, the solder layer is formed on the upper surface of the mounting substrate using screen printing. Before forming the solder layer on the surface of the mounting substrate, in order to ensure the consistency of the distribution of the solder blocks 70 on each mounting unit of the mounting substrate, a distribution rule for the solder blocks 70 is predetermined. When forming the solder layer on the surface of the mounting substrate, the solder blocks 70 are distributed according to the predetermined rule. Due to the uncertainty of the distribution of the defective units 11 on the mounting substrate, the predetermined rule cannot eliminate the defective units 11. Therefore, the solder blocks 70 are evenly distributed in each mounting unit according to the predetermined rule. That is, the solder blocks 70 are present in both the area corresponding to the good unit 12 and the area corresponding to the defective unit 11. In the area corresponding to the good unit 12, the solder blocks 70 are located on the pad 20, and in the area corresponding to the defective unit 11, the solder blocks 70 are located in the groove 21.

[0102] In some specific embodiments, to further ensure the controllability of the solder block 70 during the reflow soldering process, the size of the groove 21 is larger than the size of the solder block 70.

[0103] Figure 22 This is a schematic diagram of the component 80 being mounted on the upper surface of the mounting substrate in the packaging method provided by the present invention. Please refer to [link / reference]. Figure 16 and Figure 22 Step S162: Mount component 80 and perform reflow soldering.

[0104] In this step, a pick-and-place machine is used to accurately place the component 80 onto the pad 20 with the solder block 70. In one specific embodiment, the semiconductor structure with the component 80 mounted is sent into a reflow oven and passes through four temperature zones: preheating, holding, reflow, and cooling. During the preheating stage, the temperature is slowly increased to allow the solvent in the solder to evaporate, preventing solder splashing or damage to the component 80 due to a sudden temperature rise; during the holding stage, the temperature is kept stable to fully activate the flux and remove oxides from the metal surface; during the reflow stage, the temperature rises rapidly above the solder melting point, the solder melts and wets the soldering surface, achieving the connection between the component 80 and the pad 20; during the cooling stage, the temperature is reduced at a certain cooling rate to allow the solder to solidify and form a strong solder joint.

[0105] On the surface of the defective unit 11, the solder block 70 is located in the groove 21. During the reflow soldering process, the solder block 70 melts in the groove 21 and does not overflow onto the surface of the molding compound 40. This prevents the solder from forming solder balls or being absorbed by the pads 20 on the area corresponding to the adjacent good unit 12, thereby improving the reliability of the device.

[0106] In one specific embodiment, the mounting substrate is cut with grooves (refer to...) Figure 8 The packaging method further includes, for example, dividing the device into multiple mounting units. Figure 23 As shown, it is a schematic diagram of the packaging structure formed after cutting in the packaging method provided by the present invention. Multiple independent packaging structures are formed by cutting along the cutting line.

[0107] After the cutting process, the good unit 12 and the defective unit 11 are effectively separated. The cutting process, as a key step in product sorting and packaging, requires a process design that balances the packaging integrity of the good unit 12 with the precise removal of the defective unit 11. After cutting, the good unit 12 forms an independent package structure, with smooth and flat edges formed by the cutting process. The molding compound 40, conductive connector 50, chip 60, and pad 20 are all intact, with the upper surface of the pad 20 exposed on the upper surface of the package structure, providing a standard interface for subsequent electrical connections. The defective unit 11 is precisely grasped and separated by an automated sorting device and ultimately collected and processed as waste.

[0108] In the packaging method provided by the specific embodiments of the present invention, the upper surface of the defective unit of the mounting substrate is provided with a groove that is recessed toward the interior of the mounting substrate. When a solder layer is formed on the surface of the mounting substrate, the solder blocks of the solder layer can be distributed in the groove on the upper surface of the defective unit. During the reflow soldering process, the solder blocks melt and flow only in the groove, without overflowing onto the surface of the molding compound, thus avoiding the formation of solder balls or absorption by the pads on the area corresponding to the adjacent good unit, thereby improving the reliability of the device.

[0109] It should be noted that references to "an embodiment," "an embodiment," "an exemplary embodiment," "some embodiments," etc., in the specification indicate that the described embodiments may include specific features, structures, or characteristics, but each embodiment may not necessarily include that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. In addition, when a specific feature, structure, or characteristic is described in connection with an embodiment, whether explicitly described or not, implementing such a feature, structure, or characteristic in conjunction with other embodiments is within the knowledge of those skilled in the art.

[0110] It should be noted that the terms "comprising" and "having," and their variations, used in this invention document are intended to cover non-exclusive inclusion. The terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence, unless explicitly indicated by the context. It should be understood that such data used interchangeably where appropriate. Furthermore, embodiments and features within embodiments of this invention can be combined with each other unless otherwise specified. In addition, descriptions of well-known components and technologies have been omitted in the above description to avoid unnecessarily obscuring the concepts of this invention. In the various embodiments described above, each embodiment focuses on its differences from other embodiments; similar or identical parts between embodiments can be referred to interchangeably.

[0111] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A mounting substrate, characterized in that, It includes multiple mounting units, which are divided into good units and bad units. The upper surface of the good unit has pads, and the upper surface of the bad unit has grooves that are recessed toward the interior of the mounting substrate, corresponding to the pads on the upper surface of the good unit.

2. The mounting substrate according to claim 1, characterized in that, The position of the groove corresponds one-to-one with the position of the pad.

3. The mounting substrate according to claim 1, characterized in that, The position of one of the grooves corresponds to the position of the plurality of pads.

4. The mounting substrate according to claim 1, characterized in that, The position of one of the grooves corresponds to the position of all the pads.

5. The mounting substrate according to claim 1, characterized in that, The sidewall of the groove is stepped.

6. The mounting substrate according to claim 1, characterized in that, The mounting substrate includes: An initial substrate includes defective units and non-defective units, wherein the defective units correspond to the bad units and the non-defective units correspond to the good units; A molding compound that covers the initial substrate, wherein the upper surface of the pads at the good cells is exposed on the upper surface of the molding compound, and the grooves at the bad cells are recessed toward the inside of the molding compound.

7. The mounting substrate according to claim 6, characterized in that, The groove extends through the encapsulation to the upper surface of the initial substrate.

8. The mounting substrate according to claim 6, characterized in that, The groove extends into the encapsulation body by a predetermined distance, the predetermined distance being less than the thickness of the encapsulation body.

9. The mounting substrate according to claim 6, characterized in that, The upper surface of the molding compound is flush with the upper surface of the solder pad.

10. The mounting substrate according to claim 6, characterized in that, The upper surface of the molding compound is lower than the upper surface of the solder pad.

11. The mounting substrate according to claim 6, characterized in that, The mounting substrate further includes: A conductive connector, one end of which is disposed on the upper surface of the initial substrate, and the pad is disposed on the other end of the conductive connector; A chip is disposed on the upper surface of the initial substrate; The molding compound encapsulates the conductive connector, the chip, and the pads.

12. The mounting substrate according to claim 11, characterized in that, The chip is flip-chip or upright mounted on the upper surface of the initial substrate.

13. The mounting substrate according to claim 1, characterized in that, The mounting substrate is divided into multiple mounting units by dicing channels.

14. A packaging method, characterized in that, include: A mounting substrate is formed, the mounting substrate including a plurality of mounting units, the mounting units being divided into good units and defective units, the upper surface of the good unit having pads, and the upper surface of the defective unit having grooves that are recessed toward the interior of the mounting substrate corresponding to the pads on the upper surface of the good unit. A solder layer is formed on the upper surface of the mounting substrate. The solder layer includes a plurality of solder blocks. In the area corresponding to the good unit, the solder blocks are located on the pads, and in the area corresponding to the bad unit, the solder blocks are located in the grooves. Components are mounted and reflow soldering is performed.

15. The packaging method according to claim 14, characterized in that, The position of the groove corresponds one-to-one with the position of the pad.

16. The packaging method according to claim 14, characterized in that, The position of one of the grooves corresponds to the position of the plurality of pads.

17. The packaging method according to claim 14, characterized in that, The position of one of the grooves corresponds to the position of all the pads.

18. The packaging method according to claim 14, characterized in that, The sidewall of the groove is stepped.

19. The packaging method according to claim 14, characterized in that, The size of the groove is larger than the size of the solder block.

20. The packaging method according to claim 14, characterized in that, The step of forming the mounting substrate further includes: An initial substrate is provided, the initial substrate including defective units and non-defective units, the defective units corresponding to the bad units and the non-defective units corresponding to the good units; Conductive connectors, pads, and chips are provided at the non-defective units of the initial substrate. One end of the conductive connector is provided on the upper surface of the initial substrate, and the pad is provided at the other end of the conductive connector. Molding is performed to form a molding compound that encapsulates the conductive connector, the chip, and the pads, with the upper surface of the pads exposed on the upper surface of the molding compound. The groove is formed on the upper surface of the encapsulation corresponding to the defective unit.

21. The packaging method according to claim 20, characterized in that, The groove is formed using a cutting process.

22. The packaging method according to claim 20, characterized in that, The groove extends through the encapsulation to the upper surface of the initial substrate.

23. The packaging method according to claim 20, characterized in that, The groove extends into the encapsulation body by a predetermined distance, the predetermined distance being less than the thickness of the encapsulation body.

24. The packaging method according to claim 20, characterized in that, The upper surface of the molding compound is flush with the upper surface of the solder pad.

25. The packaging method according to claim 20, characterized in that, The upper surface of the molding compound is lower than the upper surface of the solder pad.

26. The packaging method according to claim 20, characterized in that, The molding process, which forms a molded body, further includes: Molding is performed to form an initial molding layer, which covers the conductive connector, the chip, and the pads, with the upper surface of the pads being covered by the initial molding layer; Thin the initial molding layer until the upper surface of the pads is exposed.

27. The packaging method according to claim 20, characterized in that, The chip is flip-chip or upright mounted on the upper surface of the initial substrate.

28. The packaging method according to claim 14, characterized in that, The step of forming a solder layer on the upper surface of the mounting substrate further includes: forming the solder layer on the upper surface of the mounting substrate using a screen printing process.

29. The packaging method according to claim 14, characterized in that, The mounting substrate is divided into multiple mounting units by dicing channels, and the packaging method further includes cutting along the dicing channels to form multiple independent packaging structures.

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