Packaging structure and its formation method, electronic devices

Abstract

A packaging structure and its forming method, and an electronic device, wherein in the forming method of the packaging structure, in the step of mounting a second substrate onto a first substrate, a probe structure extends into a probe groove structure. By utilizing the mechanical cooperation between the probe structure and the probe groove structure, the relative position between the second substrate and the first substrate is defined, so that the first bump and the second bump can make precise contact. Thus, during the transfer or waiting process after mounting and before reflow processing, even if external factors such as equipment vibration, airflow disturbance, or human error occur, the first substrate and the second substrate are not prone to relative displacement. This makes it possible for the first bump and the second bump to melt and form an electrical connection structure in a position-locked state when the first substrate and the second substrate are reflowed. The electrical connection structure is less prone to defects such as cold solder joints, bridging, or open circuits caused by positional misalignment, thereby improving the reliability of the electrical connection between the first substrate and the second substrate.

Description

Technical Field

[0001] The invention relates to the semiconductor field, and more particularly to a packaging structure and a method for forming the same, and electronic devices. Background Technology

[0002] In the field of semiconductor packaging technology, flip-chip packaging is a core method for achieving high-density, high-performance interconnection between chips and substrates. Flip-chip packaging involves creating conductive bumps on the active surface of the chip and flipping the chip so that the bumps directly align with the pads on the substrate surface, thus replacing traditional wire bonding. This connection structure shortens the signal transmission path, reduces inductance and resistance, and meets the miniaturization and high-speed signal transmission requirements of modern electronic devices.

[0003] In existing flip chip mounting operations, the process flow typically follows a specific sequence of operations to achieve physical connections. Specifically, the process begins by applying flux to the chip bumps or spraying flux onto the bump areas of the substrate surface. Subsequently, high-precision mounting equipment is used to optically align the chip bumps with the substrate bumps, and the chip is mounted in a preset position on the substrate. Finally, the assembled chip-substrate assembly is fed into a reflow soldering machine via a transfer system, where the bump material melts under high temperature, achieving metallurgical bonding and electrical conduction between the chip and the substrate.

[0004] However, the above packaging process has shortcomings in the connection between processes in practical applications. Summary of the Invention

[0005] The problem addressed by the embodiments of this disclosure is to provide a packaging structure and its forming method, and an electronic device, which makes it less likely for the first substrate and the second substrate to undergo relative displacement, thereby improving the reliability of the electrical connection between the first substrate and the second substrate.

[0006] This invention provides a method for forming an encapsulation structure, comprising: providing a first substrate having a plurality of first bumps and a plurality of dispersed probe groove structures formed thereon; providing a second substrate having a plurality of second bumps and a plurality of dispersed probe structures formed thereon, the probe structures being used to extend into the probe groove structures, and the positions of the probe structures corresponding to the positions of the probe groove structures; mounting the second substrate onto the first substrate such that the probe structures extend into the probe groove structures to define the relative positions between the second substrate and the first substrate, the second bumps being in contact with the first bumps; and performing a reflow treatment on the mounted second substrate and the first substrate to melt the second bumps and the first bumps to form an electrical connection structure for electrically connecting the first substrate and the second substrate.

[0007] Optionally, in the step of providing the first substrate, the probe groove structure includes an assisting groove located at the top of the first substrate and a constraint groove located at the bottom of the assisting groove, the assisting groove having inclined sidewalls; in the step of attaching the second substrate to the first substrate, the assisting groove is used to guide the probe structure into the constraint groove, and the constraint groove is used to limit the probe structure.

[0008] Optionally, the contour of the assisting groove is conical or flared.

[0009] Optionally, the profile of the constraint groove includes a straight groove.

[0010] Optionally, in the step of providing the first substrate, the probe groove structure further includes a probe welding structure formed at the bottom of the constraint groove; in the step of reflowing the second substrate and the first substrate after mounting, the probe structure is combined with the probe welding structure molten at the bottom of the constraint groove to form the combined welding structure.

[0011] Optionally, in the step of providing the second substrate, the material of the probe structure includes one or more of metals, ceramics, composite materials, and silicon-based materials; in the step of providing the first substrate, the material of the probe welding structure includes a material capable of forming a eutectic with the probe structure.

[0012] Optionally, in the step of providing the second substrate, the height of the probe structure is a first dimension, and the height of the second bump is a second dimension; in the step of providing the first substrate, the height of the first bump is a third dimension; wherein, the first dimension is greater than the sum of the second dimension and the third dimension.

[0013] Optionally, the step of providing the first substrate includes: performing a first plasma etching process on the first substrate to form the assisting groove having inclined sidewalls on the first substrate; performing a second plasma etching process on the first substrate at the bottom of the assisting groove to form a constraint groove at the bottom of the assisting groove; and forming the probe welding structure at the bottom of the constraint groove by dispensing, spraying, or coating.

[0014] Optionally, the step of providing the second substrate includes: forming the second bump on the second substrate; after the second bump is formed, forming the probe structure on the second substrate using a diffusion bonding process, or forming a probe material layer covering the second substrate and the second bump; and patterning the probe material layer to form the probe structure on the second substrate.

[0015] Optionally, the probe structure includes one or more of a cylinder, a polygonal prism, and a hemisphere.

[0016] Optionally, in the step of providing the second substrate, at least three probe structures arranged in a triangular pattern are formed on the second substrate; in the step of providing the first substrate, at least three probe groove structures arranged in a triangular pattern are formed on the first substrate.

[0017] Optionally, in the step of attaching the second substrate to the first substrate, the lateral gap between the constraint groove and the probe structure is 1 micrometer to 3 micrometers.

[0018] Optionally, the method for forming the encapsulation structure further includes: after reflowing the second substrate and the first substrate after mounting, filling the space between the second substrate and the first substrate with underfill adhesive, wherein the energy storage modulus of the underfill adhesive is lower than that of the electrical connection structure.

[0019] Optionally, in the step of providing the second substrate, the second substrate includes a chip; in the step of providing the first substrate, the first substrate includes a substrate; and in the step of mounting the second substrate onto the first substrate, the chip is mounted on a portion of the substrate.

[0020] The present invention also provides a packaging structure, comprising a first substrate including a plurality of dispersed probe slot structures; a second substrate disposed above the first substrate; a plurality of dispersed probe structures fixedly disposed at the bottom of the second substrate, wherein the probe structures extend into the probe slot structures, defining the relative position between the second substrate and the first substrate; and an electrical connection structure disposed between the first substrate and the second substrate for electrically connecting the first substrate and the second substrate.

[0021] Optionally, the probe groove structure includes an assist groove located at the top of the first substrate and a constraint groove located at the bottom of the assist groove, the assist groove having inclined sidewalls; the probe structure extends into the constraint groove of the probe groove structure.

[0022] Optionally, the profile of the assisting groove may include a conical or flared shape.

[0023] Optionally, the profile of the constraint groove includes a straight groove.

[0024] Optionally, the packaging structure further includes: a combined welding structure located between the bottom of the probe groove structure and the probe structure, and between the constraint groove and the probe structure.

[0025] Optionally, the material of the probe structure includes one or more of metals, ceramics, composite materials, and silicon-based materials; the material of the combined welding structure includes materials capable of forming a eutectic with the probe structure.

[0026] Optionally, the probe structure includes one or more of a cylinder, a polygonal prism, and a hemisphere.

[0027] Optionally, at least three probe structures arranged in a triangular pattern are disposed on the second substrate, and at least three probe groove structures arranged in a triangular pattern are disposed on the first substrate.

[0028] Optionally, the lateral spacing between the constraint groove and the probe structure is 1 micrometer to 3 micrometers.

[0029] Optionally, the encapsulation structure further includes: an underfill adhesive disposed between the second substrate and the first substrate, wherein the energy storage modulus of the underfill adhesive is lower than that of the electrical connection structure.

[0030] Optionally, the second substrate includes a chip, and the first substrate includes a substrate, with the chip located in a portion of the substrate.

[0031] The present invention provides an electronic device, including: the aforementioned packaging structure.

[0032] Compared with the prior art, the technical solution of the invention has the following advantages: In the method for forming the packaging structure provided in this embodiment, in the step of providing the first substrate, a plurality of dispersed probe groove structures are formed on the first substrate; in the step of providing the second substrate, a plurality of dispersed probe structures are formed on the second substrate, and the positions of the probe groove structures correspond to the positions of the probe structures. In the step of mounting the second substrate onto the first substrate, the probe structures extend into the probe groove structures. By utilizing the mechanical cooperation between the probe structures and the probe groove structures, the relative positions between the second substrate and the first substrate are defined, so that the first bump and the second bump can make precise contact. Therefore, during the transfer or waiting process after mounting and before reflow processing, even if external factors such as equipment vibration, airflow disturbance, or human error occur, the first substrate and the second substrate are not prone to relative displacement. This makes it easier for the first bump and the second bump to melt and form an electrical connection structure in a position-locked state when the first substrate and the second substrate are reflowed. The electrical connection structure is less prone to defects such as cold solder joints, bridging, or open circuits caused by positional misalignment, thereby improving the reliability of the electrical connection between the first substrate and the second substrate.

[0033] The packaging structure provided in this embodiment includes a first substrate, a second substrate, and an electrical connection structure disposed between the first substrate and the second substrate. The first substrate has multiple dispersed probe slot structures, and the bottom of the second substrate has multiple dispersed probe structures fixedly disposed therein, with the probe structures extending into the probe slot structures. The mechanical positioning of the probe structures extending into the probe slot structures forms a mechanical positioning mechanism between the first substrate and the second substrate, limiting the relative position between the second substrate and the first substrate. This improves the alignment between the first substrate and the second substrate, enhances the shear resistance and structural stability of the packaging structure in the horizontal direction, and makes the electrical connection structure less susceptible to mechanical stress caused by external forces or positional offsets. This provides a structural basis for the electrical conduction of the electrical connection structure, thereby improving the structural strength and reliability of the packaging structure. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0035] Figures 1 to 13 This is a schematic diagram of the steps in the method for forming the packaging structure according to an embodiment of the present invention. Detailed Implementation

[0036] As the background technology indicates, packaging processes suffer from deficiencies in process integration during practical applications. Specifically, current processes exhibit significant reliability flaws in material handling and soldering. First, in the stage where mounting is complete but reflow soldering has not yet begun, the chip and substrate are temporarily fixed together only by the surface tension and adhesion of the flux. This weak connection structure is vulnerable to external interference and is easily displaced during the transfer process to the high-temperature reflow soldering equipment by the conveyor, due to factors such as equipment vibration, ambient air convection, or accidental contact by personnel. This causes the chip bumps to deviate from their intended alignment with the substrate pads. Second, if this misalignment is solidified and soldered during the subsequent high-temperature reflow process, it will form an irreparable misalignment connection, directly leading to the scrapping of the chip and substrate due to irreversibility, resulting in increased production costs and decreased mounting yield. Even with remedial measures such as manual removal and resoldering at high temperatures, this process will subject the chip and substrate to a secondary high-temperature thermal shock. This additional thermal stress not only damages material properties but also adversely affects the long-term reliability and lifespan of the product.

[0037] To address the aforementioned technical problem, in the step of providing the first substrate, a plurality of dispersed probe groove structures are formed on the first substrate; in the step of providing the second substrate, a plurality of dispersed probe structures are formed on the second substrate, and the positions of the probe groove structures correspond to the positions of the probe structures. In the step of mounting the second substrate onto the first substrate, the probe structures extend into the probe groove structures. By utilizing the mechanical cooperation between the probe structures and the probe groove structures, the relative positions between the second substrate and the first substrate are defined, allowing the first bump and the second bump to make precise contact. Thus, during the transfer or waiting process after mounting and before reflow processing, even if external factors such as equipment vibration, airflow disturbance, or accidental human contact occur, the first substrate and the second substrate are less likely to experience relative displacement. This ensures that during the reflow processing of the mounted first substrate and the second substrate, the first bump and the second bump melt to form an electrical connection structure in a position-locked state. Defects such as cold solder joints, bridging, or open circuits caused by positional misalignment are less likely to occur in the electrical connection structure, improving the reliability of the electrical connection between the first substrate and the second substrate.

[0038] The technical solutions in the disclosed embodiments will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the invention, and not all embodiments. Based on the embodiments of the invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the invention.

[0039] This invention provides a method for forming an encapsulation structure. Figures 1 to 13 This is a schematic diagram of the steps in the method for forming the packaging structure according to an embodiment of the present invention.

[0040] refer to Figures 1 to 5 A first substrate 100 is provided, on which a plurality of first protrusions 101 and a plurality of dispersed probe groove structures 102 are formed (e.g., Figure 5 (As shown).

[0041] The first substrate 100 serves as the supporting base for the packaging structure, and the probe groove structure 102 is used in subsequent processes for the probe structure in the second substrate to be embedded.

[0042] In some embodiments, during the step of providing the first substrate 100, the first substrate 100 includes an organic substrate, a ceramic substrate, a silicon interposer, or a wafer. The substrate serves to provide a support base for the first bump 101 and the probe groove structure 102.

[0043] As an example, the substrate may include a rigid substrate or a flexible substrate. Rigid substrates include organic laminates made of FR-4 or BT resin, or ceramic substrates formed of alumina or aluminum nitride. In other examples, a silicon interlayer may also be used as the substrate.

[0044] It should be noted that the substrate has one or more conductive layers and insulating layers. The conductive layer is used for signal transmission and rewiring, while the insulating layer is used to isolate different conductive layers. The conductive layer is electrically connected to the first bump 101.

[0045] In some embodiments, the first bump 101 is a solder structure, such as a copper pillar or solder ball, grown on a metal pad of a chip or substrate for subsequent formation of an electrical connection structure.

[0046] Specifically, a plurality of first bumps 101 are arranged in an array, and the material of the first bumps 101 includes solder, such as a tin-based alloy. As an example, the first bumps 101 include micro-pitch bumps.

[0047] In some embodiments, the probe groove structure 102 is arranged in coordination with the first bump 101. As an example, the probe groove structure 102 is distributed in the peripheral or internal region of the array of first bumps 101.

[0048] like Figure 4 and Figure 5 As shown, Figure 5 yes Figure 4 The enlarged view shows that in the step of providing the first substrate 100, the probe groove structure 102 includes an assist groove 1021 located at the top of the first substrate 100 and a constraint groove 1022 located at the bottom of the assist groove 1021, the assist groove 1021 having inclined sidewalls.

[0049] The assisting groove 1021 is located at the top entrance of the probe groove structure 102. The assisting groove 1021 has an inclined sidewall. After the second substrate is attached to the first substrate 100, the probe structure in the second substrate extends into the probe groove structure 102. The inclined sidewall serves as a guide surface, allowing the probe structure on the second substrate to be smoothly embedded into the probe groove structure 102. The constraint groove 1022 at the bottom of the assisting groove 1021 is used to further limit the probe structure, restrict the displacement of the probe structure in the horizontal plane, and lock the relative position between the first substrate 100 and the second substrate.

[0050] In some embodiments, the profile of the assist groove 1021 is conical or flared. The conical or flared profile is characterized by being wider at the top and narrower at the bottom, which converts the vertically downward mounting pressure into a horizontal component force pointing towards the central axis, reducing the difficulty for the probe structure to enter the probe groove structure 102 and improving the fault tolerance of the subsequent mounting process between the first substrate 100 and the second substrate.

[0051] As an example, when the profile of the assisting groove 1021 is conical, the profile of the vertical section of the sidewall of the assisting groove 1021 is a straight line, which linearly contracts from the top opening to the bottom opening; when the profile of the assisting groove 1021 is trumpet-shaped, the profile of the vertical section of the sidewall of the assisting groove 1021 is an inwardly concave curve, whose slope gradually decreases from the top opening to the bottom opening.

[0052] In some embodiments, the contour of the constraint groove 1022 includes a straight groove. The straight groove contour of the constraint groove 1022 enables the constraint groove 1022 to precisely limit the position of the probe structure.

[0053] It should be noted that the depth of the straight groove needs to ensure that the probe structure has a certain length located in the straight groove, while also ensuring that the first protrusion 101 on the first substrate 100 contacts the second protrusion on the second substrate, so that when the first substrate 100 and the second substrate are subsequently reflowed, the first protrusion 101 and the second protrusion melt to form an electrical connection structure.

[0054] It should be noted that, in the step of providing the first substrate 100, at least three probe groove structures 102 arranged in a triangular pattern are formed on the first substrate 100.

[0055] At least three probe slot structures 102 arranged in a triangle form a multi-point positioning plane on the surface of the first substrate 100, which helps to increase the positioning accuracy between the first substrate 100 and the second substrate during subsequent mounting.

[0056] As an example, the three probe slot structures 102 are arranged in an equilateral triangle or an isosceles triangle. The number of probe slot structures 102 can also be four, arranged in a rectangular pattern.

[0057] It should be noted that the three probe groove structures 102 are set on the first substrate 100 at the edge or corner position corresponding to the second substrate, thereby more effectively suppressing the rotation of the second substrate subsequently attached to the first substrate 100 and improving the stability of positioning.

[0058] It should also be noted that, in the step of providing the first substrate 100, the probe groove structure 102 further includes a probe welding structure 1023 formed at the bottom of the constraint groove 1022.

[0059] The probe welding structure 1023 is formed at the bottom of the constraint groove 1022 structure as a connecting medium. It is used to fuse with the probe structure at the bottom of the second substrate during the subsequent reflow process to form a combined welding structure through metallurgical bonding. This fixes the first substrate 100 and the second substrate together, so that the combined welding structure can serve as a structural reinforcement of the packaging structure to bear the warping stress caused by thermal mismatch during the operation of the packaging structure and prevent the packaging structure from warping. In addition, the combined welding structure can also serve as a heat dissipation channel between the first substrate 100 and the second substrate, allowing the two to exchange heat.

[0060] In some embodiments, during the step of providing the first substrate 100, the material of the probe soldering structure 1023 includes solder paste. When the material of the probe soldering structure 1023 includes solder paste, and the probe structure is metal or has a solderable metal plating, the probe structure and the probe soldering structure 1023 can be smoothly fused together during the subsequent reflow processing of the second substrate and the first substrate 100.

[0061] As an example, solder paste includes alloys such as tin-silver-copper or tin-bismuth, and probe structures include metals, alloys, or surfaces plated with nickel or gold.

[0062] In other embodiments, the material of the probe welding structure 1023 includes a material capable of forming a eutectic bond with the probe structure. When the probe structure is a non-metallic material such as silicon or ceramic, the probe structure can form a eutectic bond with the probe welding structure 1023 during reflow processing. As an example, the material of the probe structure includes silicon or silicon carbide, which can form a eutectic bond with a eutectic solder using gold (Au) or gold-tin (AuSn).

[0063] Specifically, the step of providing the first substrate 100 includes: performing a first plasma etching process on the first substrate 100 to form an assisting groove 1021 with inclined sidewalls on the first substrate 100; performing a second plasma etching process on the first substrate 100 at the bottom of the assisting groove 1021 to form a constraint groove 1022 at the bottom of the assisting groove 1021; and forming a probe welding structure 1023 at the bottom of the constraint groove 1022 by dispensing, spraying, or coating.

[0064] The assisting groove 1021 etched by the first plasma etching process has a wide-mouthed inclined sidewall, which can better guide the probe structure into the constraint groove 1022; the second plasma etching process further vertically etches downward at the bottom of the assisting groove 1021 to form a deep groove profile with a limiting function in the horizontal direction; the dispensing, spraying or coating steps are used to form a probe welding structure 1023 at the bottom of the constraint groove 1022, providing material for the probe and the probe groove structure 102 to form a strong combined welding structure in reflow soldering.

[0065] As an example, the first plasma etching process includes: forming a first mask layer on the surface of a first substrate 100 to expose the location of a predetermined probe groove structure 102; and performing first plasma etching using the first mask layer as a mask to form an assisting groove 1021 with inclined sidewalls. The first plasma etching includes anisotropic dry etching processes.

[0066] As an example, the second plasma etching process includes: after forming the assisting trench 1021, performing a second plasma etching process on the first substrate 100 material at the bottom of the assisting trench 1021 to form a constraint trench 1022 at the bottom of the assisting trench 1021.

[0067] It should be noted that the constraint groove 1022 has a high aspect ratio and a vertical sidewall.

[0068] As an example, the second plasma etching process includes anisotropic dry etching processes, and the second plasma etching process includes deep reactive ion etching (DRIE), such that etching is performed primarily in a direction perpendicular to the surface of the first substrate 100.

[0069] As an example, the step of forming the probe soldering structure 1023 at the bottom of the assisting groove 1021 includes: injecting a measured amount of solder paste or eutectic solder into the bottom of the constraint groove 1022 using a piezoelectric jet valve or a time-pressure dispensing system. Alternatively, flux containing solder can be applied to the bottom of the constraint groove 1022 by screen printing or coating processes.

[0070] refer to Figure 6 and Figure 7 A second substrate 200 is provided, on which a plurality of second protrusions 201 and a plurality of probe structures 202 are formed. The probe structures 202 are used to extend into the probe groove structure 102, and the positions of the probe structures 202 correspond to the positions of the probe groove structure 102.

[0071] Multiple probe structures 202 arranged in a dispersed manner on the second substrate 200 serve as mechanical positioning units, which are used to extend into the probe groove structure 102, so that the second protrusion 201 and the first protrusion 101 can be aligned and contacted with high precision. In the subsequent reflow process, the second protrusion 201 is prepared to fuse with the first protrusion 101 to form a defect-free electrical connection structure.

[0072] In some embodiments, the second bump 201 is a solder structure, such as a copper pillar or solder ball, grown on a metal pad of a chip or substrate for subsequent formation of an electrical connection structure.

[0073] In some embodiments, the probe structure 202 is spaced apart from the second bump 201, and the probe structure 202 is a purely mechanical structure that does not perform electrical functions.

[0074] In some embodiments, the probe structure 202 is co-located with the second bump 201. As an example, the probe structure 202 is distributed in the peripheral or internal region of the array of second bumps 201. As an example, the second bump 201 includes micro-pitch bumps.

[0075] In some embodiments, the probe structure 202 includes one or more of a cylinder, a polygonal prism, and a hemisphere.

[0076] In some embodiments, during the step of providing the second substrate 200, the material of the probe structure 202 has a similar coefficient of thermal expansion to the material of the second substrate 200, thereby reducing the thermal stress caused by thermal mismatch. As an example, the material of the probe structure 202 includes one or more of metals, ceramics, composite materials, and silicon-based materials.

[0077] Metallic or alloy materials possess good ductility and toughness, making the probe structure 202 less prone to brittle fracture under impact. Materials with high stiffness and low coefficient of thermal expansion (CTE), such as ceramics, composites, or silicon-based materials, enable the probe structure 202 to maintain stable dimensions during high-temperature reflow soldering and have a similar coefficient of thermal expansion to the silicon-based second substrate 200, reducing stress caused by thermal mismatch at the interface between the probe structure 202 and the second substrate 200.

[0078] As an example, the metals include one or more of copper, nickel, and tungsten.

[0079] As an example, ceramics include engineering ceramics such as alumina (Al2O3) or silicon nitride (Si3N4).

[0080] As an example, silicon-based materials include monocrystalline silicon, polycrystalline silicon, or silicon carbide.

[0081] As an example, composite materials include metal matrix composites, such as SiC particle-reinforced aluminum matrix composites or polymer matrix composites.

[0082] In the step of providing the second substrate 200, at least three probe structures 202 arranged in a triangular pattern are formed on the second substrate 200, and the positions of the probe structures 202 correspond to the positions of the probe groove structures 102.

[0083] By providing at least three probe structures 202 arranged in a triangle on the second substrate 200, and with the positions of the probe structures 202 corresponding to the positions of the probe groove structures 102, a stable limiting is formed between the first substrate 100 and the second substrate 200, limiting the translation and rotation of the first substrate 100 and the second substrate 200 in the horizontal plane.

[0084] As an example, the three probe slot structures 102 are arranged in an equilateral triangle or an isosceles triangle. The number of probe slot structures 102 can also be four, arranged in a rectangular pattern.

[0085] It should be noted that the three probe groove structures 102 are set on the first substrate 100 at the edge or corner position corresponding to the second substrate 200, thereby more effectively suppressing the rotation of the second substrate 200 subsequently mounted on the first substrate 100 and improving the stability of positioning.

[0086] Specifically, the steps of providing the second substrate 200 include: forming a second bump 201 on the second substrate 200; and after the second bump 201 is formed, forming a probe structure 202 on the second substrate 200 using a diffusion bonding process.

[0087] As an example, a probe structure 202 is formed by micromachining; a metal pad is formed in the area of ​​the second substrate 200 on which the second bump 201 has been formed for forming the probe; the bottom of the probe structure 202 is brought into contact with the metal pad on the second substrate 200; under pressure and high temperature conditions, the atoms at the contact interface between the probe structure 202 and the metal pad undergo interdiffusion to form a strong metallurgical bond.

[0088] Specifically, the steps of providing the second substrate 200 include: forming a second bump 201 on the second substrate 200; after the second bump 201 is formed, forming a probe material layer covering the second substrate 200 and the second bump 201; and performing patterning processing on the probe material layer to form a probe structure 202 on the second substrate 200.

[0089] As an example, on the second substrate 200 where the second bump 201 has been formed, a probe material layer covering the second substrate 200 and the second bump 201 is formed using a physical vapor deposition process or a chemical vapor deposition process; a second mask layer is formed on the probe material layer; the probe material layer not protected by the second mask layer is etched using a dry etching process with the second mask layer as a mask to form multiple discrete probe structures 202; after forming the probe structures 202, the second mask layer is removed.

[0090] In the step of providing the second substrate 200, the second substrate 200 includes a chip. The second substrate 200 includes a chip such that the probe structure 202 is directly integrated onto the active surface of the chip.

[0091] As an example, chips include processors, memory, or radio frequency chips.

[0092] In some embodiments, the second substrate 200 includes a chip mounted on an organic substrate, ceramic substrate, or silicon interposer serving as the first substrate 100 for precise chip-to-substrate alignment. In other embodiments, the second substrate 200 includes a chip mounted on another complete wafer serving as the first substrate 100 for chip-to-wafer bonding. In still other embodiments, the second substrate 200 includes a wafer mounted on another complete wafer serving as the first substrate 100 for wafer-to-wafer bonding.

[0093] refer to Figures 8 to 11 , Figure 9 yes Figure 8 The enlarged view at point A shows that the second substrate 200 is attached to the first substrate 100, and the probe structure 202 extends into the probe groove structure 102 to define the relative position between the second substrate 200 and the first substrate 100. The second protrusion 201 is in contact with the first protrusion 101.

[0094] In this embodiment of the invention, during the step of mounting the second substrate 200 onto the first substrate 100, the probe structure 202 extends into the probe groove structure 102. By utilizing the mechanical cooperation between the probe structure 202 and the probe groove structure 102, the relative position between the second substrate 200 and the first substrate 100 is defined, allowing the first protrusion 101 and the second protrusion 201 to make precise contact. Thus, during the transfer or waiting process after mounting and before reflow processing, even if external factors such as equipment vibration, airflow disturbance, or accidental human contact occur, the first substrate 100 and the second substrate 200 are less likely to experience relative displacement. This ensures that during subsequent reflow processing of the mounted first substrate 100 and the second substrate 200, the first protrusion 101 and the second protrusion 201 melt to form an electrical connection structure in a position-locked state. The electrical connection structure is less prone to defects such as cold solder joints, bridging, or open circuits caused by positional misalignment, thereby improving the reliability of the electrical connection between the first substrate 100 and the second substrate 200.

[0095] The steps of mounting the second substrate 200 onto the first substrate 100 include: picking up the second substrate 200 using a mounting device and moving the second substrate 200 directly above the first substrate 100; aligning the probe structure 202 on the second substrate 200 with the probe groove structure 102 on the first substrate 100 using the visual alignment system of the mounting device; allowing the second substrate 200 to descend vertically, and when the tip of the probe structure 202 contacts the assist groove 1021 at the top of the probe groove structure 102, the inclined sidewall of the assist groove 1021 will generate a guiding force on the probe structure 202, causing the probe structure 202 to slide into the constraint groove 1022 below.

[0096] It should be noted that in the step of attaching the second substrate 200 onto the first substrate 100, the assisting groove 1021 is used to guide the probe structure 202 into the constraint groove 1022, and the constraint groove 1022 is used to limit the probe structure 202.

[0097] It should be noted that when the probe structure 202 enters the constraint groove 1022, the lateral gap between the probe structure 202 and the inner wall of the constraint groove 1022 is very small, which serves to limit the horizontal position of the probe structure 202. This constrains the translation and rotation of the second substrate 200 in the direction parallel to the surface of the second substrate 200, and limits the relative position of the second substrate 200 and the first substrate 100 in the horizontal direction. This allows the first protrusion 101 and the second protrusion 201 to be precisely aligned, reducing the probability of displacement caused by equipment vibration or airflow disturbance during the transfer or waiting process before reflow soldering.

[0098] As an example, such as Figure 11 As shown, in the step of attaching the second substrate 200 to the first substrate 100, the lateral gap between the constraint groove 1022 and the probe structure 202 is 1 micrometer to 3 micrometers.

[0099] It should be noted that the lateral gap between the constraint groove 1022 and the probe structure 202 should not be too large or too small. If the lateral gap is too large, it will cause excessive wobbling space between the constraint groove 1022 and the probe structure 202, reducing the positioning accuracy between the first base 100 and the second base 200, and preventing the probe structure 202 and the constraint groove 1022 from forming a tight mechanical fit. If the lateral gap is too small, the probe structure 202 will not be able to be smoothly inserted into the constraint groove 1022.

[0100] It should be noted that the lateral gap between the constraint groove 1022 and the probe structure 202 refers to the shortest distance between the inner wall of the constraint groove 1022 on one side and the outer surface of the probe structure 202.

[0101] It should also be noted that, because the projected area of ​​the chip is smaller than the projected area of ​​the second substrate 200, in the step of mounting the second substrate 200 onto the first substrate 100, the chip is mounted on a portion of the substrate, so that the area of ​​the second substrate 200 not covered by the chip can be provided with external input / output (I / O) terminals, connection lines and electronic components to form a system-in-package (SiP) module.

[0102] refer to Figure 12 The second substrate 200 and the first substrate 100 after mounting are reflowed to melt the second bump 201 and the first bump 101 to form an electrical connection structure 300, which is used to electrically connect the first substrate 100 and the second substrate 200.

[0103] The reflow process provides heat to melt the second bump 201 and the first bump 101 together and solidify them into an integral electrical connection structure 300, forming an electrical signal transmission path between the first substrate 100 and the second substrate 200. In addition, due to the limiting effect of the probe structure 202 and the probe groove, the positions of the first bump 101 and the second bump 201 can still be locked in the molten state, avoiding defects such as poor soldering, bridging or open circuit in the electrical connection structure 300 caused by liquid phase flow or position drift, thereby improving the reliability of electrical conduction of the package structure.

[0104] In some embodiments, during the reflow process of the second substrate 200 and the first substrate 100 after mounting, the probe structure 202 is combined with the probe welding structure 1023 molten at the bottom of the constraint groove 1022 to form a combined welding structure 500.

[0105] During the reflow process, the probe structure 202 and the probe groove structure 102 undergo a metallurgical reaction and fuse together to form a combined welded structure 500, thereby creating a stable connection between the probe structure 202 and the probe welded structure 1023. Furthermore, the combined welded structure 500 can also share the warping stress caused by the mismatch in the thermal expansion coefficients of the first substrate 100 and the second substrate 200 (i.e., thermal mismatch), and can also provide an auxiliary heat dissipation path.

[0106] It should be noted that during the reflow process, as the temperature exceeds the melting point of the probe welding structure 1023 material, the probe welding structure 1023 melts into a liquid state. Since the probe structure 202 has been pre-inserted into the probe groove structure 102, its tip is immersed in the molten welding material. Afterward, the temperature is lowered, and the molten welding material and the probe structure 202 solidify to form an integrated combined welding structure 500. It should be noted that the combined welding structure 500 and the first protrusion 101 and the second protrusion 201 melt to form the electrical connection structure 300 simultaneously occur in the reflow process.

[0107] Specifically, when the first and second bumps fuse, and when the probe structure and the molten probe welding structure combine, the surface tension of the liquid solder generates a self-alignment effect, pulling the second substrate 200 closer to the first substrate 100. Simultaneously, the probe structure 202 further penetrates into the probe groove structure 102 until a mechanical equilibrium position is reached. During this process, the height gap between the first substrate 100 and the second substrate 200 decreases.

[0108] It should be noted that in the step of providing the second substrate 200, the height of the probe structure 202 is the first dimension, and the height of the second protrusion 201 is the second dimension; in the step of providing the first substrate 100, the height of the first protrusion 101 is the third dimension; wherein, the first dimension is greater than the sum of the second dimension and the third dimension.

[0109] Because the first dimension is greater than the sum of the second and third dimensions, in the step of attaching the second substrate 200 to the first substrate 100, the probe structure 202 has already entered the probe groove structure 102 before the second bump 201 and the first bump 101 come into contact. The probe structure 202 and the probe groove structure 102 play a mechanical guiding and limiting role to prevent the bump from colliding in an misaligned state.

[0110] As an example, the depth of the assisting groove 1021 is a fourth dimension. The first dimension is greater than the sum of the second, third, and fourth dimensions. This ensures that when the first protrusion 101 and the second protrusion 201 come into contact, the probe structure 202 has already passed through the assisting groove 1021 and entered the constraint groove 1022.

[0111] refer to Figure 13 The method for forming the encapsulation structure further includes: after reflowing the second substrate 200 and the first substrate 100 after mounting, filling the space between the second substrate 200 and the first substrate 100 with a bottom filler 400, wherein the energy storage modulus of the bottom filler 400 is lower than that of the electrical connection structure 300.

[0112] The underfill 400 has a low energy storage modulus. Utilizing the relatively flexible nature of the underfill 400, the compressive force exerted by the underfill 400 on the electrical connection structure 300 is relatively small during thermal cycling. Furthermore, since the anti-warping and stress dispersion functions within the encapsulation structure are mainly undertaken by the rigid composite welded structure 500, the low energy storage modulus of the underfill 400 reduces the rigid constraint on the electrical connection structure 300 during thermal expansion. This reduces the risk of cracks or delamination in the electrical connection structure 300 due to stress concentration, improves signal transmission quality, and helps extend the service life of the encapsulation structure. In some embodiments, the storage modulus of the underfill 400 is lower than that of the electrical connection structure 300 (i.e., the solder joint, such as lead-free solder like SAC305). A lower storage modulus of the underfill 400 indicates that the underfill 400 is softer and more flexible.

[0113] As an example, the material of the underfill adhesive 400 includes epoxy resin or a flexible adhesive with silicone as a base material.

[0114] The step of filling the gap between the second substrate 200 and the first substrate 100 with underfill adhesive 400 includes: applying liquid underfill adhesive 400 in a linear or dotted manner along one or more edges of the second substrate 200 using an underfill process; utilizing capillary effect, the liquid underfill adhesive is automatically drawn in and flows to fill the gap between the first substrate 100 and the second substrate 200, covering all electrical connection structures 300. After filling, the liquid underfill adhesive is cured to form underfill adhesive 400.

[0115] It should be noted that the bottom filler 400 is also filled between the probe structure 202 and the probe groove structure 102. First, this provides additional fixation and support for the mechanical fit between the probe structure 202 and the probe groove structure 102, preventing loosening during long-term use or under vibration. Second, the bottom filler 400 between the probe structure 202 and the probe groove structure 102 can also seal the area, preventing moisture or contaminants from entering and improving reliability.

[0116] Accordingly, refer to Figure 13 This invention provides a packaging structure comprising: a first substrate 100, the first substrate 100 including a plurality of dispersedly arranged probe groove structures 102; a second substrate 200 disposed above the first substrate 100; a plurality of dispersedly arranged probe structures 202 fixedly disposed at the bottom of the second substrate 200, and the probe structures 202 extending into the probe groove structures 102, defining the relative position between the second substrate 200 and the first substrate 100; and an electrical connection structure 300 disposed between the first substrate 100 and the second substrate 200 for electrically connecting the first substrate 100 and the second substrate 200.

[0117] The packaging structure provided in this embodiment includes a first substrate 100, a second substrate 200, and an electrical connection structure 300 disposed between the first substrate 100 and the second substrate 200. The first substrate 100 has a plurality of dispersedly arranged probe slot structures 102, and the bottom of the second substrate 200 is fixedly provided with a plurality of dispersedly arranged probe structures 202, with the probe structures 202 extending into the probe slot structures 102. The mechanical limiting fit of the probe structures 202 extending into the probe slot structures 102 forms a mechanical positioning mechanism between the first substrate 100 and the second substrate 200, limiting the relative position between the second substrate 200 and the first substrate 100. This improves the alignment between the first substrate 100 and the second substrate 200, enhances the shear resistance and structural stability of the packaging structure in the horizontal direction, and makes the electrical connection structure 300 less susceptible to mechanical stress caused by external forces or positional offsets. This provides a structural basis for the electrical conduction of the electrical connection structure 300, thereby improving the structural strength and reliability of the packaging structure.

[0118] It should be noted that, in combination Figure 11 As shown, the electrical connection structure 300 is formed by fusing the second protrusion 201 in the second substrate 200 with the first protrusion 101 in the first substrate 100 after the second substrate 200 is attached to the first substrate 100. The probe structure 202 extends into the probe groove structure 102 to define the relative position between the second substrate 200 and the first substrate 100, and the second protrusion 201 is in contact with the first protrusion 101.

[0119] The first substrate 100 provides a support base for the probe slot structure 102.

[0120] In some embodiments, the first substrate 100 includes an organic substrate, a ceramic substrate, a silicon interposer, or a wafer.

[0121] As an example, the first substrate 100 includes a rigid substrate or a flexible substrate. The rigid substrate includes an organic laminate made of FR-4 or BT resin, or a ceramic substrate formed of alumina or aluminum nitride. In other examples, a silicon interlayer may also be used as the substrate.

[0122] It should be noted that the first substrate 100 has one or more conductive layers and insulating layers. The conductive layer is used for signal transmission and rewiring, while the insulating layer is used to isolate different conductive layers. The conductive layer is electrically connected to the first bump 101.

[0123] In some embodiments, the probe slots are arranged in conjunction with the electrical connection structure 300. As an example, the probe slot structures 102 are distributed in the peripheral or internal regions of the electrical connection structure 300.

[0124] In some embodiments, the probe groove structure 102 includes an assist groove 1021 located at the top of the first base 100 and a constraint groove 1022 located at the bottom of the assist groove 1021, the assist groove 1021 having inclined sidewalls; the probe structure 202 extends into the constraint groove 1022 of the probe groove structure 102.

[0125] The assisting groove 1021 is located at the top entrance of the probe groove structure 102. The assisting groove 1021 has an inclined sidewall. When the second substrate 200 is attached to the first substrate 100, so that the probe structure 202 in the second substrate 200 extends into the probe groove structure 102, the inclined sidewall serves as a guide surface, so that the probe structure 202 on the second substrate 200 can be smoothly embedded into the probe groove structure 102. The constraint groove 1022 at the bottom of the assisting groove 1021 is used to further limit the probe structure 202, limit the horizontal displacement of the probe structure 202, and lock the relative position between the first substrate 100 and the second substrate 200.

[0126] In some embodiments, the profile of the assist groove 1021 is conical or flared. The conical or flared profile is characterized by being wider at the top and narrower at the bottom, which converts the vertically downward mounting pressure into a horizontal component force pointing towards the central axis, reducing the difficulty for the probe structure 202 to enter the probe groove structure 102 and improving the fault tolerance of the process when mounting the first substrate 100 and the second substrate 200.

[0127] As an example, when the profile of the assisting groove 1021 is conical, the profile of the vertical section of the sidewall of the assisting groove 1021 is a straight line, which linearly contracts from the top opening to the bottom opening; when the profile of the assisting groove 1021 is trumpet-shaped, the profile of the vertical section of the sidewall of the assisting groove 1021 is an inwardly concave curve, whose slope gradually decreases from the top opening to the bottom opening.

[0128] In some embodiments, the contour of the constraint groove 1022 includes a straight groove. The straight groove contour of the constraint groove 1022 allows it to precisely limit the position of the probe structure 202, thereby preventing relative displacement between the first substrate 100 and the second substrate 200 during the transfer or waiting process after mounting and before reflow processing, even in the event of external factors such as equipment vibration, airflow disturbance, or accidental human contact. It should be noted that at least three probe slot structures 102 arranged in a triangular pattern are disposed on the first substrate 100.

[0129] At least three probe slot structures 102 arranged in a triangle form a multi-point positioning plane on the surface of the first substrate 100, which helps to increase the positioning accuracy between the first substrate 100 and the second substrate 200 during the mounting process.

[0130] As an example, the three probe slot structures 102 are arranged in an equilateral triangle or an isosceles triangle. The number of probe slot structures 102 can also be four, arranged in a rectangular pattern.

[0131] It should be noted that the three probe groove structures 102 are set on the first substrate 100 corresponding to the edge or corner position of the second substrate 200, and the probe structure 202 of the second substrate 200 is set in the probe groove structure 102, thereby more effectively suppressing the rotation of the second substrate 200 on the first substrate 100 and improving the positioning stability between the first substrate 100 and the second substrate 200.

[0132] Multiple probe structures 202 are arranged in a dispersed manner and fixedly disposed at the bottom of the second substrate 200, with the probe structures 202 extending into the probe groove structure 102, defining the relative position between the second substrate 200 and the first substrate 100. Multiple probe structures 202 arranged in a dispersed manner on the second substrate 200 serve as mechanical positioning units, which are used to extend into the probe groove structure 102, so that the second protrusion 201 and the first protrusion 101 can be aligned and contacted with high precision.

[0133] In some embodiments, the probe structure 202 is spaced apart from the electrical connection structure 300, and the probe structure 202 is a purely mechanical structure that does not perform electrical functions.

[0134] In some embodiments, the probe structure 202 is co-located with the electrical connection structure 300. As an example, the probe structure 202 is distributed in the peripheral or internal regions of the array of electrical connection structures 300. As an example, the electrical connection structure 300 includes micro-pitch bumps.

[0135] In some embodiments, the probe structure 202 includes one or more of a cylinder, a polygonal prism, and a hemisphere.

[0136] In some embodiments, the material of the probe structure 202 has a similar coefficient of thermal expansion to the material of the second substrate 200, which can gradually reduce the thermal stress caused by thermal mismatch. As an example, the material of the probe structure 202 includes one or more of metals, ceramics, composite materials, and silicon-based materials.

[0137] Metallic or alloy materials possess good ductility and toughness, making the probe structure 202 less prone to brittle fracture under impact. Materials with high stiffness and low coefficient of thermal expansion (CTE), such as ceramics, composite materials, or silicon-based materials, enable the probe structure 202 to maintain stable dimensions after high-temperature reflow treatment and to have a similar coefficient of thermal expansion to the second substrate 200, reducing stress caused by thermal mismatch at the interface between the probe structure 202 and the second substrate 200.

[0138] As an example, the metals include one or more of copper, nickel, and tungsten.

[0139] As an example, ceramics include engineering ceramics such as alumina (Al2O3) or silicon nitride (Si3N4).

[0140] As an example, silicon-based materials include monocrystalline silicon, polycrystalline silicon, or silicon carbide.

[0141] As an example, composite materials include metal matrix composites, such as SiC particle-reinforced aluminum matrix composites or polymer matrix composites.

[0142] The electrical connection structure 300 is used to electrically connect the first substrate 100 and the second substrate 200. As an example, the material of the electrical connection structure 300 includes copper or tin.

[0143] The packaging structure also includes: a combined welding structure 500 located between the bottom of the probe groove structure 102 and the probe structure 202, and a constraint groove 1022 between the probe structure 202.

[0144] The combined welding structure 500 is formed by metallurgically bonding the probe structure 202 in the second substrate 200 and the probe welding structure 1023 in the probe groove of the first substrate 100 during the reflow process, so that the first substrate 100 and the second substrate 200 are fixedly combined together. The combined welding structure 500 can serve as a structural reinforcement of the packaging structure to bear the warping stress caused by thermal mismatch during the operation of the packaging structure and prevent the packaging structure from warping. In addition, the combined welding structure 500 can also serve as a heat dissipation channel between the first substrate 100 and the second substrate 200, allowing heat to be transferred between the two.

[0145] It should be noted that the material of the combined welding structure 500 includes materials that can form a eutectic with the probe structure 202.

[0146] In some embodiments, the probe structure 202 is made of one or more of metals, ceramics, composite materials, silicon-based materials, and solder paste.

[0147] At least three probe structures 202 arranged in a triangle are disposed on the second substrate 200, and the positions of the probe structures 202 correspond to the positions of the probe groove structures 102.

[0148] By providing at least three probe structures 202 arranged in a triangle on the second substrate 200, and with the positions of the probe structures 202 corresponding to the positions of the probe groove structures 102, a stable limiting is formed between the first substrate 100 and the second substrate 200, limiting the translation and rotation of the first substrate 100 and the second substrate 200 in the horizontal plane.

[0149] As an example, the three probe slot structures 102 are arranged in an equilateral triangle or an isosceles triangle. The number of probe slot structures 102 can also be four, arranged in a rectangular pattern.

[0150] It should be noted that the three probe groove structures 102 are set on the first substrate 100 at the edge or corner position corresponding to the second substrate 200, thereby more effectively suppressing the relative rotation of the first substrate 100 and the second substrate 200 and improving the stability of positioning.

[0151] The second substrate 200 includes a chip. The second substrate 200 includes a chip such that the probe structure 202 is directly integrated onto the active surface of the chip.

[0152] As an example, chips include processors, memory, or radio frequency chips.

[0153] In some embodiments, the second substrate 200 includes a chip mounted on an organic substrate, ceramic substrate, or silicon interposer serving as the first substrate 100 for precise chip-to-substrate alignment. In other embodiments, the second substrate 200 includes a chip mounted on another complete wafer serving as the first substrate 100. In still other embodiments, the second substrate 200 includes a wafer mounted on another complete wafer serving as the first substrate 100, achieving wafer-to-wafer bonding.

[0154] It should be noted that because the lateral gap between the probe structure 202 and the inner wall of the constraint groove 1022 is very small, it serves to limit the lateral position of the probe structure 202, constraining the translation and rotation of the second substrate 200 in the direction parallel to the surface of the second substrate 200, and limiting the relative position of the second substrate 200 and the first substrate 100 in the horizontal direction, so that the first protrusion 101 and the second protrusion 201 can be precisely aligned, reducing the probability of displacement caused by equipment vibration or airflow disturbance during the transfer or waiting process before reflow soldering.

[0155] As an example, the lateral gap between the constraint groove 1022 and the probe structure 202 is 1 micrometer to 3 micrometers.

[0156] It should be noted that the lateral gap between the constraint groove 1022 and the probe structure 202 should not be too large or too small. If the lateral gap is too large, it will cause excessive wobbling space between the constraint groove 1022 and the probe structure 202, reducing the positioning accuracy between the first base 100 and the second base 200, and preventing the probe structure 202 and the constraint groove 1022 from forming a tight mechanical fit. If the lateral gap is too small, the probe structure 202 will not be able to be smoothly inserted into the constraint groove 1022.

[0157] It should be noted that the lateral gap between the constraint groove 1022 and the probe structure 202 refers to the shortest distance between the inner wall of the constraint groove 1022 on one side and the outer surface of the probe structure 202.

[0158] It should also be noted that because the projected area of ​​the chip is smaller than the projected area of ​​the second substrate 200, the chip is mounted on a portion of the substrate. This allows the areas of the second substrate 200 not covered by the chip to be equipped with external input / output (I / O) terminals, connection lines, and electronic components, thus forming a system-in-package (SiP) module.

[0159] The combined welding structure 500 enables the probe structure 202 and the probe groove structure 102 to form a stable connection. In addition, the combined welding structure 500 can also share the warping stress caused by the mismatch of the thermal expansion coefficients of the first substrate 100 and the second substrate 200 (i.e., thermal mismatch), and can also provide an auxiliary heat dissipation path.

[0160] It should be noted that the height of the probe structure 202 is the first dimension, and the height of the second protrusion 201 is the second dimension; in the step of providing the first substrate 100, the height of the first protrusion 101 is the third dimension; wherein, the first dimension is greater than the sum of the second dimension and the third dimension.

[0161] Because the first dimension is greater than the sum of the second and third dimensions, in the step of attaching the second substrate 200 to the first substrate 100, the probe structure 202 has already entered the probe groove before the second bump 201 and the first bump 101 come into contact. The probe structure 202 and the probe groove play a mechanical guiding and limiting role to prevent the bump from colliding in an misaligned state.

[0162] As an example, the depth of the assisting groove 1021 is a fourth dimension. The first dimension is greater than the sum of the second, third, and fourth dimensions. This ensures that when the first protrusion 101 and the second protrusion 201 come into contact, the probe structure 202 has already passed through the assisting groove 1021 and entered the constraint groove 1022.

[0163] The method for forming the encapsulation structure further includes: after reflowing the second substrate 200 and the first substrate 100 after mounting, filling the space between the second substrate 200 and the first substrate 100 with underfill adhesive 400, wherein the energy storage modulus of the underfill adhesive 400 is lower than the energy storage modulus of the solder joint formed by the fusion bonding of the second bump 201 and the first bump 101.

[0164] The underfill 400 has a low energy storage modulus. Utilizing the relatively flexible nature of the underfill 400, the compressive force exerted by the underfill 400 on the electrical connection structure 300 is relatively small during thermal cycling. Furthermore, since the anti-warping and stress dispersion functions within the encapsulation structure are mainly undertaken by the rigid composite welded structure 500, the low energy storage modulus of the underfill 400 reduces the rigid constraint on the electrical connection structure 300 during thermal expansion. This reduces the risk of cracks or delamination in the electrical connection structure 300 due to stress concentration, improves signal transmission quality, and helps extend the service life of the encapsulation structure. In some embodiments, the storage modulus of the underfill 400 is lower than that of the electrical connection structure 300 (i.e., solder joints, such as lead-free solder like SAC305). The lower storage modulus of the underfill 400 indicates that the underfill 400 is softer and more flexible.

[0165] As an example, the material of the underfill adhesive 400 includes epoxy resin or a flexible adhesive with silicone as a base material.

[0166] It should be noted that the bottom filler 400 also forms between the probe structure 202 and the probe groove structure 102. First, this provides additional fixation and support for the mechanical fit between the probe structure 202 and the probe groove structure 102, preventing loosening during long-term use or under vibration. Second, the bottom filler 400 between the probe structure 202 and the probe groove structure 102 can also seal the area, preventing moisture or contaminants from entering and improving reliability.

[0167] Accordingly, the present invention also provides an electronic device. The electronic device includes the packaging structure described in any embodiment.

[0168] The packaging structure is a component of electronic devices. As can be seen from the foregoing analysis, the packaging structure provided by the embodiments of the present invention can reduce the risk of component microcracks or connection damage caused by internal shrinkage stress, effectively improve the stability and reliability of the packaging structure, thereby increasing the yield and consequently improving the quality of electronic devices.

[0169] Among them, electronic devices can be smartphones, wearable devices, video game devices, etc.

[0170] The packaging structure of the present invention can be formed using the forming method described in the foregoing embodiments, or it can be formed using other forming methods. For a detailed description of the packaging structure described in this embodiment, please refer to the corresponding descriptions in the foregoing embodiments; these descriptions will not be repeated here.

[0171] While the embodiments of the present invention have been disclosed above, the invention is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the invention should be determined by the scope defined in the claims.

Claims

1. A method for forming an encapsulation structure, characterized in that, include: A first substrate is provided, on which a plurality of first protrusions and a plurality of probe groove structures are formed; A second substrate is provided, on which a plurality of second protrusions and a plurality of dispersed probe structures are formed, the probe structures being used to extend into the probe groove structure, and the positions of the probe structures corresponding to the positions of the probe groove structure; The second substrate is attached to the first substrate, and the probe structure extends into the probe groove structure to define the relative position between the second substrate and the first substrate, with the second protrusion contacting the first protrusion; The second substrate and the first substrate after mounting are reflowed to melt the second bump and the first bump to form an electrical connection structure for electrically connecting the first substrate and the second substrate.

2. The method for forming the packaging structure as described in claim 1, characterized in that, In the step of providing the first substrate, the probe groove structure includes an assisting groove located at the top of the first substrate and a constraint groove located at the bottom of the assisting groove, the assisting groove having inclined sidewalls; In the step of attaching the second substrate to the first substrate, the assisting groove is used to guide the probe structure into the constraint groove, and the constraint groove is used to limit the position of the probe structure.

3. The method for forming the packaging structure as described in claim 2, characterized in that, The contour of the assisting groove is conical or trumpet-shaped.

4. The method for forming the packaging structure as described in claim 2, characterized in that, The contour of the constraint groove includes a straight groove.

5. The method for forming the packaging structure as described in claim 2, characterized in that, In the step of providing the first substrate, the probe groove structure further includes a probe welding structure formed at the bottom of the constraint groove; In the step of reflowing the second substrate and the first substrate after mounting, the probe structure is combined with the probe welding structure molten at the bottom of the constraint groove to form a combined welding structure.

6. The method for forming the packaging structure as described in claim 5, characterized in that, In the step of providing the second substrate, the material of the probe structure includes one or more of metals, ceramics, composite materials, and silicon-based materials; In the step of providing the first substrate, the material of the probe welding structure includes a material capable of forming a eutectic with the probe structure.

7. The method for forming the packaging structure as described in claim 1, characterized in that, In the step of providing the second substrate, the height of the probe structure is a first dimension, and the height of the second bump is a second dimension; In the step of providing the first substrate, the height of the first protrusion is the third dimension; Wherein, the first dimension is greater than the sum of the second dimension and the third dimension.

8. The method for forming the packaging structure as described in claim 5, characterized in that, The steps for providing the first matrix include: The first substrate is subjected to a first plasma etching process to form the assisting groove with inclined sidewalls on the first substrate; A second plasma etching process is performed on the first substrate at the bottom of the assisting groove to form a constraint groove at the bottom of the assisting groove; The probe welding structure is formed at the bottom of the constraint groove by dispensing, spraying, or coating.

9. The method for forming the packaging structure as described in claim 1, characterized in that, The step of providing the second matrix includes: The second protrusion is formed on the second substrate; After the second bump is formed, the probe structure is formed on the second substrate using a diffusion bonding process, or a probe material layer covering the second substrate and the second bump is formed; the probe material layer is patterned, and the probe structure is formed on the second substrate.

10. The method for forming the packaging structure as described in claim 1, characterized in that, The probe structure includes one or more of a cylinder, a polygonal prism, and a hemisphere.

11. The method for forming the packaging structure as described in claim 1, characterized in that, In the step of providing the second substrate, at least three probe structures arranged in a triangular pattern are formed on the second substrate; In the step of providing the first substrate, at least three probe groove structures arranged in a triangular pattern are formed on the first substrate.

12. The method for forming the packaging structure as described in claim 2, characterized in that, In the step of attaching the second substrate to the first substrate, the lateral gap between the constraint groove and the probe structure is 1 micrometer to 3 micrometers.

13. The method for forming the packaging structure as described in claim 1, characterized in that, The method for forming the encapsulation structure further includes: after reflowing the second substrate and the first substrate after mounting, filling the space between the second substrate and the first substrate with underfill adhesive, wherein the energy storage modulus of the underfill adhesive is lower than that of the electrical connection structure.

14. The method for forming the packaging structure as described in claim 1, characterized in that, In the step of providing the second substrate, the second substrate includes a chip; In the step of providing the first substrate, the first substrate includes a substrate; In the step of mounting the second substrate onto the first substrate, the chip is mounted on a portion of the substrate.

15. A packaging structure, characterized in that, include: A first substrate, comprising a plurality of probe groove structures arranged in a dispersed manner; The second substrate is disposed above the first substrate; Multiple probe structures are arranged in a dispersed manner and fixedly disposed at the bottom of the second substrate, and the probe structures extend into the probe groove structure, defining the relative position between the second substrate and the first substrate; An electrical connection structure is disposed between the first substrate and the second substrate for electrically connecting the first substrate and the second substrate.

16. The packaging structure as described in claim 15, characterized in that, The probe groove structure includes an assist groove located at the top of the first substrate and a constraint groove located at the bottom of the assist groove, the assist groove having inclined sidewalls; The probe structure extends into the constraint groove of the probe groove structure.

17. The packaging structure as described in claim 16, characterized in that, The profile of the assisting groove includes a conical or trumpet shape.

18. The packaging structure as described in claim 16, characterized in that, The contour of the constraint groove includes a straight groove.

19. The packaging structure as described in claim 16, characterized in that, The packaging structure further includes: A combined welding structure is located between the bottom of the probe groove structure and the probe structure, and between the constraint groove and the probe structure.

20. The packaging structure as described in claim 19, characterized in that, The probe structure is made of one or more of the following materials: metal, ceramic, composite material, and silicon-based material. The material of the combined welding structure includes materials capable of forming a eutectic with the probe structure.

21. The packaging structure as described in claim 15, characterized in that, The probe structure includes one or more of a cylinder, a polygonal prism, and a hemisphere.

22. The packaging structure as described in claim 15, characterized in that, At least three probe structures arranged in a triangular pattern are disposed on the second substrate, and at least three probe groove structures arranged in a triangular pattern are disposed on the first substrate.

23. The packaging structure as described in claim 16, characterized in that, The lateral spacing between the constraint groove and the probe structure is 1 micrometer to 3 micrometers.

24. The packaging structure as described in claim 15, characterized in that, The packaging structure further includes: A bottom filler is disposed between the second substrate and the first substrate, wherein the energy storage modulus of the bottom filler is lower than that of the electrical connection structure.

25. The packaging structure as described in claim 15, characterized in that, The second substrate includes a chip, and the first substrate includes a substrate, with the chip located in a portion of the substrate.

26. An electronic device, characterized in that, Includes the packaging structure as described in any one of claims 15 to 25.

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