Package structure

Abstract

The embodiment of the utility model provides a packaging structure. The packaging structure comprises a substrate; the metal cover is arranged on the substrate, and an accommodating space is defined by the metal cover and the substrate; the wafer is positioned in the accommodating space; and a thermally conductive layer disposed between the metal cap and the wafer, in which the thermally conductive layer includes: first metal particles, the surfaces of which include first curved surfaces; and a first nanowire, the first nanowire comprising: a first end face; the second end face is opposite to the first end face; the main body part is positioned between the first end surface and the second end surface; wherein the main body portion includes a first curved portion extending along a first curved surface of the first metal particle. According to the technical scheme, the first nanowire extends along the first bent surface of the first metal particle, so that the heat dissipation effect of the packaging structure is at least improved. The embodiment of the utility model also provides another packaging structure.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and more specifically, to a packaging structure. Background Art

[0002] With the continuous development of the semiconductor industry, there are more and more heat sources in the packaging structure. In the prior art, a heat-conducting layer made of a thermal interface material (TIM) is formed on the back side of the wafer to transfer the heat generated by the wafer. Generally, a thermal interface material used to form a heat-conducting layer can be a pure low-temperature solder material (solder). Before forming this heat-conducting layer, it is necessary to metallize the back side of the wafer to plate a metal layer, and solder on the metal layer to form a heat-conducting layer. However, during the soldering process, this solder material will react with adjacent metals (such as adjacent heat sinks) and consume adjacent metals, and the formed heat-conducting layer will overflow to an undesirable position. In addition, the existing plating solution may leave more impurities at the interface of the plated layer, and these impurities will serve as nucleation sites for vacancies, and because the vacancy absorption capacity at the interface between the plated metal layer and the solder material is poor, these vacancies may form continuous Kirkendall voids in the heat-conducting layer later, which will affect the thermal conductivity efficiency of the formed heat-conducting layer.

[0003] In addition, another thermal interface material used to form the thermal conductive layer may include a polymer adhesive material and metal particles mixed therein. Since most metal particles are spherical in shape with spherical sidewalls, most of the sidewalls of the metal particles will be in contact with the polymer adhesive material with lower thermal conductivity. For example, after the metal particles are in contact with each other, the contact area between the sidewalls of the metal particles with spherical sidewalls is smaller, and the spherical sidewalls will have incontactable parts. Therefore, most of the other sidewalls that are not in contact with each other will be filled with polymer materials with lower thermal conductivity, resulting in the failure to improve the thermal conductivity of the thermal conductive layer. For example, see Figure 1 and FIG. 2A to FIG. 2B As shown in Figure 1 The scanning electron microscope image of the heat-conducting layer including the polymer adhesive material and the metal particles in the prior art is shown, and FIG. 2A to FIG. 2B They are shown respectively Figure 1 Schematic diagram of the metal particles in the region 12 of the thermally conductive layer. Figure 1 and FIG. 2A to FIG. 2B As shown, Figure 2A Four adjacent metal particles are shown in Figure 2BThree adjacent metal particles are shown. After the adjacent metal particles contact each other, larger gap regions 14, 16 and 18 are formed between the side walls of the metal particles that are not in contact with each other. The gap regions 14, 16 and 18 will be filled with polymer materials. Since the thermal conductivity of polymer materials is very low, this will make the thermal conductivity of the heat-conducting layer poor. Utility Model Content

[0004] In view of the above problems existing in the prior art, an embodiment of the present application proposes a packaging structure including a heat-conducting layer, and the heat-conducting layer can at least improve the heat dissipation effect of the packaging structure.

[0005] According to one aspect of the present application, a packaging structure is provided, which includes: a substrate; a metal cover, which is arranged on the substrate and defines a housing space with the substrate; a chip, which is located in the housing space; and a thermal conductive layer, which is arranged between the metal cover and the chip, wherein the thermal conductive layer includes: a first metal particle, the surface of the first metal particle includes a first curved surface; and a first nanowire, the first nanowire includes: a first end face; a second end face, which is opposite to the first end face; and a main body, which is located between the first end face and the second end face; wherein the main body includes a first curved portion extending along the first curved surface of the first metal particle.

[0006] In one or more embodiments, the thermal conductive layer further includes a second metal particle adjacent to the first metal particle, the second metal particle having a second curved surface, wherein the body portion has a second curved portion extending along the second curved surface.

[0007] In one or more embodiments, the main body of the first nanowire has a third portion located between the first curved surface and the second curved surface, and the third portion connects the first curved portion and the second curved portion.

[0008] In one or more embodiments, the first curved surface contacts the second curved surface, and the main body of the first nanowire is bent toward the contact point between the first curved surface and the second curved surface.

[0009] In one or more embodiments, the thermal conductive layer further includes a second nanowire and a third metal particle adjacent to the second metal particle, the third metal particle having a third curved surface, the second nanowire and the first nanowire extending along different portions of the second curved surface, wherein the second nanowire has a portion extending along the second curved surface of the second metal particle and another portion extending along the third curved surface.

[0010] In one or more embodiments, the first curved portion is adjacent to the first curved surface of the first metal particle without contacting the first curved surface, and the first nanowire extends from the metal cap toward the wafer.

[0011] In one or more embodiments, the first curved portion of the first nanowire is in direct contact with the first curved surface of the first metal particle.

[0012] In one or more embodiments, the second curved portion of the first nanowire is in direct contact with the second curved surface of the second metal particle.

[0013] In one or more embodiments, the first end surface of the first nanowire is closer to the first curved surface of the first metal particle than the second end surface, and the first end surface is spaced apart from the first metal particle.

[0014] In one or more embodiments, the second end surface of the first nanowire is closer to the second curved surface of the second metal particle than the first end surface, and the second end surface is spaced apart from the second metal particle.

[0015] In one or more embodiments, the first curved surface, the second curved surface and the third curved surface are all arc surfaces.

[0016] In one or more embodiments, the first metal particles are in contact with the second metal particles, and the third metal particles are spaced apart from the first metal particles and spaced apart from the second metal particles.

[0017] In one or more embodiments, a portion of the second nanowire is in direct contact with the second curved surface of the second metal particle, and another portion of the second nanowire is in direct contact with the third curved surface of the third metal particle.

[0018] In one or more embodiments, the first metal particles are copper, the second metal particles are tin, and the first nanowires are copper nanowires.

[0019] In one or more embodiments, the first bent portion of the first nanowire is closer to the first end surface than to the second end surface.

[0020] In one or more embodiments, the thermal conductive layer further includes a binder, and the binder binds the first metal particles and the first nanowires together.

[0021] In one or more embodiments, the first metal particles are spherical particles.

[0022] In one or more embodiments, a vertical projection of the wafer on the heat conducting layer is located within a boundary of the heat conducting layer.

[0023] In one or more embodiments, the wafer is electrically connected to the substrate through solder bumps, and the package structure further includes a filling material located between the substrate and the wafer and surrounding the solder bumps.

[0024] According to another aspect of the present application, a packaging structure is provided, which includes: a substrate; a metal cover, which is arranged on the substrate and defines a housing space with the substrate; a chip, which is located in the housing space; and a thermal conductive layer, which is arranged between the metal cover and the chip, wherein the thermal conductive layer includes: a first metal particle and a second metal particle, the first metal particle and the second metal particle respectively have a first arc surface and a second arc surface, the first arc surface and the second arc surface are partially in contact; and a first nanowire, the first nanowire extends along a non-contact portion between the first arc surface and the second arc surface and extends toward a contact position.

[0025] In one or more embodiments, the first nanowire is a copper nanowire.

[0026] In one or more embodiments, a vertical projection of the wafer on the heat conducting layer is located within a boundary of the heat conducting layer.

[0027] In one or more embodiments, the die is electrically connected to the substrate via solder bumps.

[0028] In one or more embodiments, the package structure further includes a filling material between the substrate and the wafer and surrounding the solder bumps.

[0029] The beneficial technical effects of the utility model are:

[0030] The thermal conductive layer of the packaging structure of the embodiment of the present application comprises a first metal particle comprising a first curved surface and a first nanowire comprising a main body, and the first nanowire is extended along the first curved surface of the first metal particle, thereby at least improving the heat dissipation effect of the packaging structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings without creative work. It is worth noting that according to the standard practice of the industry, the various components are not drawn to scale and are only used for illustration purposes. In fact, for the clarity of discussion, the size of each component can be arbitrarily increased or reduced.

[0032] Figure 1 A scanning electron microscope image of a portion of a heat conducting layer in the prior art is shown.

[0033] FIG. 2A to FIG. 2B Shows Figure 1 Schematic diagram of the metal particles in the area of ​​the thermal conductive layer.

[0034] Figure 3is a schematic cross-sectional view of a packaging structure according to an embodiment of the present application,

[0035] Figure 4 Schematic diagram of some metal particles in the thermal conductive layer according to an embodiment of the present application.

[0036] Figure 5 FIG. 4 is a schematic diagram of some metal particles in a heat conducting layer according to another embodiment of the present application.

[0037] Figure 6 is a schematic cross-sectional view of a packaging structure according to another embodiment of the present application.

[0038] Figure 7 is a scanning electron microscope image of the nanowire according to an embodiment of the present application.

[0039] Figure 8 is a scanning electron microscope image of a thermal conductive layer according to an embodiment of the present application.

[0040] 9A to 9F It is an energy spectrum diagram of element analysis in the thermal conductive layer according to an embodiment of the present application. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0042] The following disclosure provides many different embodiments or examples for realizing different features of the provided subject matter. Specific examples of components and arrangements will be described below to simplify the present invention. Of course, these are merely examples and are not intended to limit the present invention. For example, in the following description, forming a first component above or on a second component may include an embodiment in which the first component and the second component are in direct contact, and may also include an embodiment in which an additional component is formed between the first component and the second component so that the first component and the second component may not be in direct contact. Moreover, the present invention may repeatedly refer to numbers and / or letters in various examples. This repetition is only for simplicity and clarity, and does not itself represent the relationship between the various embodiments and / or configurations discussed.

[0043] In addition, the embodiments in the present application and the features in the embodiments may be combined with each other in the absence of conflicts. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. It should be understood that the specific structures shown in the drawings are only for the sake of convenience of explanation and are not intended to limit the present application. When describing a specific figure, other structures not described in the drawings may be provided according to actual needs and are not intended to limit the present application.

[0044] Figure 3 is a schematic cross-sectional view of a packaging structure 100 according to an embodiment of the present application, Figure 4 FIG. 1 is a schematic diagram of some metal particles in the heat conducting layer 108 according to an embodiment of the present application. Figure 3 and Figure 4 The package structure 100 includes a substrate 102 and a metal cover 104 disposed on the substrate 102, wherein the metal cover 104 and the substrate 102 define an accommodation space. The package structure 100 also includes a chip 106 located in the accommodation space, and a heat-conducting layer 108 disposed between the metal cover 104 and the chip 106. The heat-conducting layer 108 includes a first metal particle 110 and a first nanowire 112, wherein the surface of the first metal particle 110 includes a first curved surface 110C, and the first nanowire 112 includes a first end surface 114, a second end surface 116 opposite to the first end surface 114, and a main body 118 located between the first end surface 114 and the second end surface 116, wherein the main body 118 includes a first curved portion 118A1, and the first curved portion 118A1 extends along the first curved surface 110C of the first metal particle 110. The heat-conducting layer 108 of the package structure 100 of the embodiment of the present application comprises a first metal particle 110 including a first curved surface 110C and a first nanowire 112. By extending the first nanowire 110 along the first curved surface 110C of the first metal particle 110, heat can be conducted away from the first metal particle 110 via the heat dissipation path formed by the first nanowire 110, thereby at least improving the heat dissipation effect of the package structure 100. In addition, since the main body 118 of the first nanowire 112 comprises a first curved portion 118A1 extending along the first curved surface 110C of the first metal particle 110, compared with a nanowire without a curved portion, the first nanowire 112 having the first curved portion 118A1 increases the coverage of the first nanowire 112 on the surface of the first metal particle 110, thereby further improving the heat conduction efficiency of the heat-conducting layer 108.

[0045] Next reference Figure 3 and Figure 4 As shown, in some embodiments, the first nanowire 112 extends from the metal cover 104, and the contact between the first nanowire 112 and the metal cover 104 helps to improve heat dissipation. It can be understood that, for example, one end surface of the first nanowire 112 is in contact with the metal cover 104. In some embodiments, as Figure 4As shown, the first curved portion 118A1 may be adjacent to the first curved surface 110C of the first metal particle 110 without contacting the first curved surface 110C. In other embodiments, the first curved portion 118A1 of the first nanowire 112 may also be in direct contact with the first curved surface 110C of the first metal particle 110. In the embodiment where the first curved portion 118A1 is in direct contact with the first curved surface 110C, the first end surface 114 of the first nanowire 112 is closer to the first curved surface 110C of the first metal particle 110 than the second end surface 116, and the first end surface 114 is spaced apart from the first metal particle 110. Accordingly, the first curved portion 118A1 of the first nanowire 112 is closer to the first end surface 114 than the second end surface 116.

[0046] In some embodiments, the heat-conducting layer 108 further includes a second metal particle 120 adjacent to the first metal particle 110, the second metal particle 120 having a second curved surface 120C, wherein the main body 118 of the first nanowire 112 has a second curved portion 118A2 extending along the second curved surface 120C. Compared with the nanowire without a curved portion, the first nanowire 112 having the first curved portion 118A1 and the second curved portion 118A2 increases the coverage of the first nanowire 112 on the surface of the first metal particle 110 and the second metal particle 120, thereby further improving the heat conduction efficiency of the heat-conducting layer 108. In some embodiments, the first curved surface 110C of the first metal particle 110 and the second curved surface 120C of the second metal particle 120 are both arc surfaces, and correspondingly, the first curved portion 118A1 and the second curved portion 118A2 have an arc shape matching the arc surface. In some embodiments, the second curved portion 118A2 may be adjacent to the second curved surface 120C of the second metal particle 120 without contacting the second curved surface 120C. In other embodiments, the second curved portion 118A2 of the first nanowire 112 may also be in direct contact with the second curved surface 120C of the second metal particle 120. In the embodiment where the second curved portion 118A2 is in direct contact with the second curved surface 120C, the second end surface 116 of the first nanowire 112 is closer to the second curved surface 120C of the second metal particle 120 than the first end surface 114, and the second end surface 116 is spaced apart from the second metal particle 120.

[0047] Next reference Figure 4As shown, in some embodiments, the main body 118 of the first nanowire 112 has a third portion 118A3 located between the first curved surface 110C and the second curved surface 120C, and the third portion 118A3 connects the first curved portion 118A1 and the second curved portion 118A2. In some embodiments, the first curved surface 110C contacts the second curved surface 120C, and the main body 118 of the first nanowire 112 bends toward the contact between the first curved surface 110C and the second curved surface 120C. In other words, the third portion 118A3 of the main body 118 bends toward the contact between the first curved surface 110C and the second curved surface 120C, and therefore, the third portion 118A3 can also be referred to as a third curved portion.

[0048] Next reference Figure 4 As shown, in some embodiments, the thermal conductive layer 108 further includes a second nanowire 122 and a third metal particle 124 adjacent to the second metal particle 120 and having a third curved surface 124C, the second nanowire 122 and the first nanowire 112 extend along different portions of the second curved surface 120C of the second metal particle 120, and the second nanowire 122 has a portion 122A1 extending along the second curved surface 120C of the second metal particle 120 and another portion 122A2 extending along the third curved surface 124C. In further embodiments, the portion 122A1 of the second nanowire 122 is in direct contact with the second curved surface 120C of the second metal particle 120, and the other portion 122A2 of the second nanowire 122 is in direct contact with the third curved surface 124C of the third metal particle 124 ( Figure 4 However, the present application is not limited thereto. In other embodiments, for example, Figure 4 As shown, another portion 122A2 of the second nanowire 122 is spaced apart from the third curved surface 124C of the third metal particle 124, and the heat conductive layer 108 further includes a third nanowire 128 located between the second nanowire 122 and the third metal particle 124, and the third nanowire 128 also extends along the third curved surface 124C of the third metal particle 124 and directly contacts the third curved surface 124C. In further embodiments, the third nanowire 128 may directly contact the second nanowire 122. In some embodiments, the first curved surface 110C, the second curved surface 120C, and the third curved surface 124C are all arc surfaces. In some embodiments, the first metal particle 110, the second metal particle 120, and the third metal particle 124 are all spherical particles, and correspondingly, the entire surface of the first metal particle 110, the entire surface of the second metal particle 120, and the entire surface of the third metal particle 124 are all circular curved surfaces.

[0049] In some embodiments, the first metal particle 110 is in contact with the second metal particle 120, and the third metal particle 124 is spaced apart from the first metal particle 110 and the second metal particle 120. Accordingly, a first gap is formed between the first metal particle 110 and the third metal particle 124, and a second gap is formed between the second metal particle 120 and the third metal particle 124, and the second nanowire 122 passes through the first gap and the second gap. In some embodiments, the thermal conductive layer 108 further includes a fourth nanowire 130 located between the second nanowire 122 and the first metal particle 110, and the fourth nanowire 130 penetrates into the first gap so that an end of the fourth nanowire 130 penetrates into the second metal particle 120.

[0050] In some embodiments, the first nanowire 112 is a copper nanowire. In some embodiments, the thermal conductive layer 108 may further include more metal particles and nanowires, such as Figure 4 As shown in the figure, the fifth nanowire 132 extends along the second curved surface 120C of the second metal particle 120 and the end thereof contacts the first nanowire 112. The nanowires in the heat-conducting layer 108 may all be copper nanowires. Compared with the prior art of increasing thermal conductivity by adding silver particles to the heat-conducting layer, since the thermal conductivity of the copper nanowire matches the thermal conductivity of the silver particles (i.e., the thermal conductivity of the two may be the same) and the price is relatively cheaper, the embodiment of the present application can reduce the amount of silver particles used in the heat-conducting layer 108 by adding copper nanowires to the heat-conducting layer 108, which not only greatly reduces the cost of the heat-conducting layer 108, but also makes the thermal conductivity of the heat-conducting layer 108 higher. In some embodiments, the first metal particle 110 is copper, and the second metal particle 120 is tin.

[0051] Combined with reference Figure 3 to Figure 4 As shown, in some embodiments, the heat-conducting layer 108 further includes a binder 126, and the binder 126 binds the first metal particles 110 and the first nanowires 112 together. In some embodiments, the heat-conducting layer 108 may further include more metal particles and nanowires, and the binder 126 binds the metal particles and the nanowires together. Since the heat-conducting layer 108 in the embodiment of the present application still has the binder 126 after sintering (rather than having no binder), the heat-conducting layer 108 may also be referred to as a semi-sintering type (semi sintering type) silver thermal interface material. In addition, compared with the heat-conducting layer that does not include nanowires in the prior art, in the heat-conducting layer 108 in the embodiment of the present application, since more nanowires are distributed in the heat-conducting layer 108, the heat-conducting layer 108 may have more nanowires that contact the metal cover 104 and the wafer 106, so as to conduct away the heat generated by the wafer 106, thereby further improving the thermal conductivity of the heat-conducting layer 108.

[0052] In some embodiments, the binder 126 is formed of an organic polymer material. In other embodiments, the binder 126 can be formed of silicone oil. That is, the binder 126 wraps the metal particles and nanowires so that the binder 126 that does not react with the metal (such as copper or tin) in the metal cover 104 is in direct contact with the metal cover 104. In this way, compared with the prior art in which the heat-conducting layer is formed by a low-temperature pure soft solder material, the package structure 100 of the embodiment of the present application eliminates the technical problem of metal consumption generated when the pure soft solder material contacts the metal cover. In addition, the package structure 100 of the embodiment of the present application uses an organic polymer material as the main material of the heat-conducting layer 108 to bond the metal cover 104 and the chip 106 together. Compared with the prior art in which the heat-conducting layer is formed by a low-temperature pure soft solder material, the heat-conducting layer 108 can be in direct contact with the chip 106 without metallization on the back side of the chip 106, and because the shape of the polymer material is easier to control, this also avoids the technical problem of the soft solder material overflowing when the heat-conducting layer is formed by a pure soft solder material in the prior art. In addition, since the nanowires have a larger specific surface area and a stronger ability to absorb vacancies, the embodiment of the present application can prevent the accumulation of vacancies in the thermal conductive layer 108 , thereby reducing the possibility of holes being formed in the thermal conductive layer 108 .

[0053] refer to Figure 3 As shown, in some embodiments, the vertical projection of the wafer 106 on the heat-conducting layer 108 is located within the boundary of the heat-conducting layer 108. Accordingly, the lateral dimensions (e.g., length and width) of the heat-conducting layer 108 are greater than the lateral dimensions of the wafer 106. However, the present application is not limited thereto, and the lateral dimensions (e.g., length and width) of the heat-conducting layer 108 may be equal to the lateral dimensions of the wafer 106, for example, see Figure 6 As shown. In some embodiments, the chip 106 is electrically connected to the substrate 102 through the solder bump 134. In a further embodiment, the package structure 100 also includes a filling material 136 located between the substrate 102 and the chip 106 and surrounding the solder bump 134. It is not difficult to understand that in the cross-sectional view, in the accommodation space defined by the metal plate 104 and the substrate 102, the solder bump 134 and the filling material 136 are also located in the accommodation space. In some embodiments, the package structure 100 also includes a conductive connector 138 located below the substrate 102 and electrically connected to the substrate 102. The conductive connector 138 can be a solder bump.

[0054] Figure 5 FIG. 1 is a schematic diagram of some metal particles in the heat conducting layer 108 according to another embodiment of the present application. Figure 5 The embodiment shown is Figure 4 The embodiment shown in FIG. 1 is similar to the embodiment shown in FIG. 1 , except that the heat conductive layer 108 may not include the fourth nanowire 130 located between the second nanowire 122 and the first metal particle 110 (see FIG. 1 ). Figure 4 shown).

[0055] Figure 6 is a schematic cross-sectional view of a packaging structure 200 according to another embodiment of the present application. Figure 6 The embodiment shown is Figure 3 The embodiment shown in FIG. 1 is similar to that shown in FIG. 1 , except that the lateral dimensions (eg, length and width) of the thermally conductive layer 108 may be equal to the lateral dimensions of the wafer 106. In addition, the sidewalls of the thermally conductive layer 108 are vertically aligned with the sidewalls of the wafer 106.

[0056] Figure 7 and Figure 8 They are respectively a scanning electron microscope image of the nanowire according to an embodiment of the present application and a thermal conductive layer 108 (see for example Figure 3 ) of the scanning electron microscope. Figure 7 The fabricated nanowires are shown in FIG. 8 . It is not difficult to see from the figure that the diameter of the nanowires is in the range of several nanometers. Figure 8 The heat conducting layer 108 is shown in FIG. Figure 3 ) includes nanowires 140, metal particles 142 including copper particles, tin particles and bismuth particles, and a binder 126 that binds the metal particles 142 and the nanowires 140 together.

[0057] 9A to 9F The heat conducting layer 108 according to the embodiment of the present application (see for example Figure 3 ) in the energy spectrum of elemental analysis. 9A to 9F The heat conducting layer 108 is shown separately (see for example Figure 3 ) include carbon (C) element, oxygen (O) element, silicon (Si) element, copper (Cu) element, bismuth (Bi) element, and tin (Sn) element, wherein, Fig.9A The bright gray part is the distribution of carbon. Fig. 9B The yellow part in the middle is the distribution of oxygen. Fig. 9C The green part in the middle is the distribution of silicon. Fig.9D The red part in the middle is the distribution of copper elements. Fig.9E The blue part of the middle rock is the distribution of bismuth, and Fig.9F The emerald-colored part is the distribution of tin. 9A to 9F Ka1_2, Ka1, Ma1, and La1 are signals from an energy dispersive X-ray spectrometer (EDX) elemental analysis machine.

[0058] According to another aspect of the present application, another packaging structure 100 is provided. Figure 3 and Figure 4The packaging structure 100 includes a substrate 102, a metal cover 104 disposed on the substrate 102 and defining an accommodating space with the substrate 102, a chip 106 located in the accommodating space, and a heat-conducting layer 108 disposed between the metal cover 104 and the chip 106. The heat-conducting layer 108 includes a first nanowire 112 and a first metal particle 110 and a second metal particle 120 having a first arc surface and a second arc surface respectively. The first arc surface and the second arc surface are partially in contact with each other. The first nanowire 112 extends along the non-contacting portion between the first arc surface and the second arc surface and extends toward the contact position. Compared with the prior art in which the side walls of the metal particles that are not in contact with each other are filled with a polymer material with low thermal conductivity, the heat-conducting layer 108 of the embodiment of the present application has a first nanowire 112 extending along the non-contacting portion between the first arc surface of the first metal particle 110 and the second arc surface of the second metal particle 120, so that heat can be conducted from the first metal particle 110 through the heat dissipation path formed by the first nanowire 110, thereby at least improving the heat dissipation effect of the package structure 100. In addition, since the first nanowire 112 extends along the non-contacting portion between the first arc surface of the first metal particle 110 and the second arc surface of the second metal particle 120, the coverage of the first nanowire 112 on the surface of the first metal particle 110 is increased, thereby further improving the thermal conductivity efficiency of the heat-conducting layer 108. In some embodiments, the first nanowire 112 can extend from the metal cover 104 toward the wafer 106, and the contact between the first nanowire 112 and the metal cover 104 helps to improve the heat dissipation efficiency.

[0059] Next reference Figure 3 and Figure 4 It is not difficult to understand that the steps of forming the thermal conductive layer 108 of the embodiment of the present application may include: forming a mixture of nanowires and metal particles, the nanowires and the metal particles are squeezed against each other, and since the nanowires (such as copper nanowires) have higher strength and ductility (rigidity) than a whole piece of metal (such as copper metal), the mutual squeezing makes the nanowires have a curved portion extending along the curved surface of the metal particles; bonding the nanowires and the metal particles together through the adhesive 126; sintering to form the thermal conductive layer 108 interconnecting the wafer 106 and the metal cover 104. In the early stage of manufacturing the thermal conductive layer 108, the connection between the nanowires is as small as possible. In addition, controlling the ratio (such as mass ratio) between the metal particles (including copper particles and tin particles, etc.), the nanowires and the adhesive 126 in the thermal conductive layer 108 is also important for forming a thermal conductive layer 108 with high thermal conductivity.

[0060] The heat-conducting layer of the packaging structure provided by the utility model has nanowires extending along the curved surface of the metal particles, so that heat can be conducted away from the metal particles via the heat dissipation path formed by the nanowires, at least improving the heat dissipation effect of the packaging structure. In addition, the curved portion of the nanowire extending along the curved surface of the metal particle increases the coverage of the nanowire on the surface of the metal particle, thereby further improving the thermal conductivity of the heat-conducting layer. In addition, compared with the prior art of adding silver particles to the heat-conducting layer to increase thermal conductivity, the embodiments of the present application can reduce the amount of silver particles used in the heat-conducting layer by adding copper nanowires to the heat-conducting layer, which not only greatly reduces the cost of the heat-conducting layer, but also makes the thermal conductivity of the heat-conducting layer higher. The heat-conducting layer of the packaging structure provided by the utility model can provide good interconnection and high thermal conductivity between the chip and the metal cover.

[0061] It should be understood that the various features of the various embodiments of the present application can be replaced and combined. The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any combination of the various embodiments within the spirit and principle of the present application, as well as any modification, equivalent replacement, improvement, etc. made to the embodiments, shall be included in the protection scope of the present application.

Claims

1. A packaging structure, characterized in that: include: substrate; A metal cover, disposed on the substrate and defining a containing space with the substrate; A chip is located in the accommodating space; as well as A heat-conducting layer is disposed between the metal cover and the wafer, wherein the heat-conducting layer comprises: a first metal particle, a surface of the first metal particle comprising a first curved surface; and A first nanowire, the first nanowire comprising: a first end surface; a second end surface, opposite to the first end surface; and A main body portion, located between the first end surface and the second end surface; The main body includes a first curved portion extending along the first curved surface of the first metal particle.

2. The packaging structure according to claim 1, characterized in that: The thermal conductive layer further includes a second metal particle adjacent to the first metal particle, the second metal particle having a second curved surface, wherein the body portion has a second curved portion extending along the second curved surface.

3. The packaging structure according to claim 2, characterized in that: The main body of the first nanowire has a third portion located between the first curved surface and the second curved surface, and the third portion connects the first curved portion and the second curved portion.

4. The packaging structure according to claim 2, characterized in that: The first curved surface contacts the second curved surface, and the main body of the first nanowire is bent toward the contact point between the first curved surface and the second curved surface.

5. The packaging structure according to claim 2, characterized in that: The thermal conductive layer further includes a second nanowire and a third metal particle adjacent to the second metal particle, the third metal particle having a third curved surface, the second nanowire and the first nanowire extending along different portions of the second curved surface, The second nanowire has a portion extending along the second curved surface of the second metal particle and another portion extending along the third curved surface.

6. The packaging structure according to claim 1, characterized in that: The first curved portion is adjacent to the first curved surface of the first metal particle without contacting the first curved surface, and the first nanowire extends from the metal cap toward the wafer.

7. The packaging structure according to claim 2, characterized in that: The first metal particles are copper, the second metal particles are tin, and the first nanowires are copper nanowires.

8. The packaging structure according to claim 1, characterized in that: The heat conductive layer further includes a binder, which binds the first metal particles and the first nanowires together.

9. The packaging structure according to claim 1, characterized in that: A vertical projection of the wafer on the heat-conducting layer is located within a boundary range of the heat-conducting layer.

10. The packaging structure according to claim 1, characterized in that: The wafer is electrically connected to the substrate through solder bumps, and the package structure further includes a filling material located between the substrate and the wafer and surrounding the solder bumps.

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