Joint structure

Abstract

The embodiment of the utility model provides a bonding structure, and the bonding structure comprises a first bonding pad and a first nanowire structure, and the first nanowire structure comprises a first buffer nanorod disposed on the first bonding pad; and the conductive layer is arranged on the first bonding pad and the first buffer nano column, and the conductive layer wraps the outer side wall of the first buffer nano column. According to the technical scheme, the bonding structure at least can provide more stable bonding through the first buffer nanorod with the outer side wall covered by the conductive layer.

Description

Technical Field

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

[0002] With the continuous development of the semiconductor industry, the bonding structure for electrical connection has become increasingly important. In the existing bonding structure including nanowires, since after bonding, the contact area between some nanowires is small (for example, only point contact) and the friction between them is not enough to fix each other, collisions may occur between the nanowires, which may cause defects such as cracks, fractures and / or deformations in the nanowires. Therefore, such a bonding structure will have poor electrical performance or even fail.

[0003] Figure 1 A schematic cross-sectional view of a semiconductor structure 10 including a bonding structure 12 in the prior art is shown, and Figure 2 Shows Figure 1 FIG. 1 is an enlarged schematic diagram of a region 14 of a bonding structure 12. Figure 1 and Figure 2 As shown, Figure 1 The bonding structure 12 is shown to electrically connect the upper wafer 16 with the lower substrate 18, and the bonding structure 12 includes an upper pad 20 connected to the wafer 16, a lower pad 22 connected to the substrate 18, and nanowires 24 and 26 extending downward and upward from the upper pad 20 and the lower pad 22, respectively. After the nanowires 24 and 26 are bonded, part of the nanowires 24 and part of the nanowires 26 are only in point contact with each other. Due to this point contact and insufficient friction between the nanowires 24 and 26, cracks and fractures (such as Figure 2 28) and / or deformed (as shown in FIG. Figure 2 Further, due to defects such as less contact (e.g., only point contact) and nanowire deformation, the electrical performance of the bonding structure is poor or even fails. Therefore, a bonding structure capable of providing a more stable bonding is provided. Utility Model Content

[0004] In view of the above problems existing in the prior art, an embodiment of the present application proposes a bonding structure, which can at least provide a more stable bonding.

[0005] According to one aspect of the present application, a bonding structure is provided, which includes: a first pad, and a first nanowire structure, the first nanowire structure including: a first buffer nanocolumn, disposed on the first pad; and a conductive layer, disposed on the first pad and the first buffer nanocolumn, and the conductive layer covers the outer wall of the first buffer nanocolumn.

[0006] In one or more embodiments, the bonding structure also includes a second pad and a second conductive nanowire, the second pad is disposed above the first pad, and the second conductive nanowire is disposed on the second pad, the portion of the conductive layer covering the outer wall of the first buffer nanocolumn is the outer conductive wall, and the side surface of the second conductive nanowire contacts the outer conductive wall.

[0007] In one or more embodiments, the conductive layer further covers the top surface of the first buffer nanorods.

[0008] In one or more embodiments, the side surface of the second conductive nanowire is a rough surface formed by a plurality of conductive wires extending obliquely toward the second pad, and the plurality of conductive wires penetrate into the outer conductive wall.

[0009] In one or more embodiments, the conductive layer is a conductive layer formed of a graphene material.

[0010] In one or more embodiments, the portion of the conductive layer covering the outer sidewall of the first buffer nanocolumn is an outer conductive wall, and the outer conductive wall includes a plurality of conductive lines extending obliquely toward the first pad.

[0011] In one or more embodiments, the plurality of conductive wires and the second conductive nanowires are an integral piece formed of the same conductive material.

[0012] In one or more embodiments, the first nanowire structure further includes a second buffer nanocolumn, which is disposed on the first pad and is adjacent to and spaced apart from the first buffer nanocolumn, and the conductive layer further covers an outer sidewall of the second buffer nanocolumn.

[0013] In one or more embodiments, the bonding structure also includes a second pad and a second conductive nanowire, the second pad is disposed above the first pad, and the second conductive nanowire is disposed above the second pad, and the second conductive nanowire is located between the conductive layer covering the outer wall of the first buffer nanocolumn and the outer wall of the second buffer nanocolumn.

[0014] In one or more embodiments, a portion of the conductive layer covering the top surface of the first buffer nanorod is in direct contact with the second pad.

[0015] In one or more embodiments, a portion of the conductive layer directly contacting the first pad is in direct contact with a top surface of the second conductive nanowire.

[0016] In one or more embodiments, the first buffer nano-pillars and the second buffer nano-pillars are elastic pillars.

[0017] In one or more embodiments, the outer conductive wall is a flat surface.

[0018] In one or more embodiments, the second conductive nanowire is a metal nanowire.

[0019] In one or more embodiments, the bonding structure further includes a protection layer surrounding and directly contacting the first pad, the second pad, the conductive layer, and the second conductive nanowire.

[0020] In one or more embodiments, the diameter of the second conductive nanowire is in a range between 2 micrometers and 50 micrometers.

[0021] According to another aspect of the present application, a bonding structure is provided, which includes: a first pad; a plurality of buffer nanopillars extending upward from the first pad; a conductive layer covering at least the outer side walls of the plurality of buffer nanopillars; a second pad located above the first pad; and a second conductive nanowire extending downward from the second pad, the second conductive nanowire being located between the conductive layers covering the outer side walls of two adjacent buffer nanopillars.

[0022] In one or more embodiments, the buffer nano-pillars are pillars formed of a thermoplastic resin.

[0023] In one or more embodiments, the diameter of the buffer nano-pillars is in a range between 2 microns and 50 microns.

[0024] In one or more embodiments, every two adjacent buffer nano-pillars in the plurality of buffer nano-pillars are equally spaced apart.

[0025] The beneficial technical effects of the utility model are:

[0026] Since the bonding structure of the embodiment of the present application has a buffer nano-column whose outer sidewall is covered by a conductive layer, the bonding structure can at least provide a more stable bonding through the buffering effect of the buffer nano-column. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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.

[0028] Figure 1 FIG. 4 is a schematic cross-sectional view of a semiconductor structure including a bonding structure in the prior art.

[0029] Figure 2 Shows Figure 1 A magnified schematic diagram of a region of the junction structure.

[0030] Figure 3 A schematic cross-sectional view of a semiconductor structure including a bonding structure according to an embodiment of the present application is shown.

[0031] Figure 4 The embodiment of the present application is shown Figure 1 A magnified schematic diagram of a region of the junction structure.

[0032] Figure 5 The embodiment according to the present application is shown Figure 4 An enlarged view of a region of the junction structure is shown.

[0033] Figure 6 Another embodiment of the present application is shown Figure 1 A magnified schematic diagram of a region of the junction structure.

[0034] Figures 7 to 25 Schematic cross-sectional views at various stages of forming a semiconductor structure including a bonding structure according to an embodiment of the present application are shown.

[0035] Fig.26 A three-dimensional view of a semiconductor structure according to another embodiment of the present application is shown.

[0036] Fig. 27 A three-dimensional view of a semiconductor structure according to another embodiment of the present application is shown. DETAILED DESCRIPTION

[0037] 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.

[0038] 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.

[0039] 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.

[0040] Figure 3 is a schematic cross-sectional view of a semiconductor structure 100 including a bonding structure 110 according to an embodiment of the present application, and Figure 4 The embodiment of the present application is shown Figure 1 FIG. 1 is an enlarged schematic diagram of a region 112 of a bonding structure 110. Figure 3 and Figure 4 The bonding structure 110 includes a first pad 114 and a first nanowire structure 116. The first nanowire structure 116 includes a first buffer nanocolumn 118A1 disposed on the first pad 114 and a conductive layer 120 disposed on the first pad 114 and the first buffer nanocolumn 118A1, wherein the conductive layer 120 covers the outer sidewall of the first buffer nanocolumn 118A1. The bonding structure 110 of the embodiment of the present application has the first buffer nanocolumn 118A1 whose outer sidewall is covered by the conductive layer 120. Since the first buffer nanocolumn 118A1 can buffer various stresses of the bonding structure 110 during and after the bonding process, the bonding structure 110 can at least provide a more stable bonding. It is obviously understandable that when the first nanowire structure 116 is bonded to the element to be bonded, the element to be bonded will apply stress to the first nanowire structure 116. In this process, the first buffer nanocolumn 118A1 can buffer the stress to avoid defects such as cracks, deformation, and / or ruptures in the first nanowire structure 116 and the element to be bonded, thereby making the first nanowire structure 116 and the element to be bonded more stably bonded.

[0041] Join reference Figure 3 and Figure 4In some embodiments, the bonding structure 110 may further include a second pad 122 disposed above the first pad 114 and a second conductive nanowire 124 disposed on the second pad 122. The portion of the conductive layer 120 that covers the outer side wall of the first buffer nanocolumn 118A1 may be referred to as an outer conductive wall 120S1, and the side surface of the second conductive nanowire 124 contacts the outer conductive wall 120S1. During or after the bonding of the first nanowire structure 116 with the second conductive nanowire 124, the first buffer nanocolumn 118A1 may buffer the impact caused by, for example, small friction when the second conductive nanowire 124 contacts the outer conductive wall 120S1, thereby avoiding defects such as cracks, deformation, and / or ruptures in the first nanowire structure 116 and the second conductive nanowire 124. Therefore, the bonding structure 110 may have better electrical properties.

[0042] In some embodiments, the first nanowire structure 116 may further include a second buffer nanocolumn 118A2 disposed on the first pad 114, the second buffer nanocolumn 118A2 being adjacent to and spaced apart from the first buffer nanocolumn 118A1, and the conductive layer 120 also covering the outer sidewall of the second buffer nanocolumn 118A2. In some embodiments, the conductive layer 120 may also cover the top surface of the first buffer nanocolumn 118A1. In addition, the conductive layer 120 may also cover the top surface of the second buffer nanocolumn 118A2. In some embodiments, the portion of the conductive layer 120 covering the top surface of the first buffer nanocolumn 118A1 is in direct contact with the second pad 122. In addition, the portion of the conductive layer 120 covering the top surface of the second buffer nanocolumn 118A2 is in direct contact with the second pad 122. That is, the first buffer nanorod 118A1 and the second buffer nanorod 118A2 both extend directly from the first pad 114 toward the second pad 122 , and the conductive layer 120 conformally covers the outer sidewalls and top surfaces of the first buffer nanorod 118A1 and the second buffer nanorod 118A2 .

[0043] For ease of description, in the following content, the outer conductive wall 120S1 of the conductive layer 120 is referred to as the first outer conductive wall. In the embodiment where the first nanowire structure 116 further includes the second buffer nanocolumn 118A2, the portion of the conductive layer 120 covering the outer wall of the second buffer nanocolumn 118A2 is referred to as the second outer conductive wall 120S2, and the portion of the conductive layer 120 covering the top surface of the first buffer nanocolumn 118A1 and the portion covering the top surface of the second buffer nanocolumn 118A2 are referred to as the first top-side conductive wall 120T1 and the second top-side conductive wall 120T2, respectively. In some embodiments, the conductive layer 120 further includes a lateral portion 120A connecting the first outer conductive wall and the second outer conductive wall 120S2, and the lateral portion 120A is located on the first pad 114 and directly contacts the first pad 114. The first outer conductive wall, the first top side conductive wall 120T1 , the lateral portion 120A, the second outer conductive wall 120S2 , and the second top side conductive wall 120T2 of the conductive layer 120 are connected to each other to conformally cover the first buffer nano-pillar 118A1 , the second buffer nano-pillar 118A2 , and the first pad 114 .

[0044] In a further embodiment where the first nanowire structure 116 includes the second buffer nanorod 118A2, the second conductive nanowire 124 is located between the conductive layers 120 that cover the outer sidewalls of the first buffer nanorod 118A1 and the outer sidewalls of the second buffer nanorod 118A2. Figure 4 As shown, the top surface of the second conductive nanowire 124 is in direct contact with the portion of the conductive layer 120 that directly contacts the first pad 114. That is, the top surface of the second conductive nanowire 124 is in direct contact with the extension 120A of the conductive layer 120. During or after the bonding of the first nanowire structure 116 with the second conductive nanowire 124, the first buffer nanocolumn 118A1 and the second buffer nanocolumn 118A2 can buffer stress and provide a greater pressure between the conductive layer 120 and the second conductive nanowire 124, which makes the conductive layer 120 and the second conductive nanowire 124 more closely in contact, so that the conductive layer 120 and the second conductive nanowire 124 can be bonded more stably, and the bonding structure 110 can have better electrical performance.

[0045] In some embodiments, the first buffer nanorod 118A1 and the second buffer nanorod 118A2 are elastic rods. Therefore, the pressure provided by the first buffer nanorod 118A1 and the second buffer nanorod 118A2 can also be referred to as elastic force. In order to more clearly explain the elastic force provided by the first buffer nanorod 118A1 and the second buffer nanorod 118A2, the following is combined with Figure 5 Provide explanation. Figure 5 According to the embodiment of the present application Figure 4 An enlarged view of the region 128 of the bonding structure 110 is shown. According to the principle of elastic dynamics, F = E·ε·A, and Fμ = μ·F, where F and Fμ are the total elastic force and friction force, and E, ε, A and μ represent the elastic modulus, strain, contact area and friction coefficient, respectively. Figure 5 As shown, taking the second buffer nanorod 118A2 side as an example, by positioning the second conductive nanowire 124 between the conductive layer 120 covering the outer side wall of the first buffer nanorod 118A1 and the outer side wall of the second buffer nanorod 118A2, the second buffer nanorod 118A2 and the second conductive nanowire 124 bonded to each other can provide a total elastic force F (e.g. Figure 5 As shown by the arrow 130 in the middle, the total elastic force F and its reaction force R (as shown in FIG. Figure 5 The large pressure provided by the conductive layer 120 and the second conductive nanowire 124 provides a large friction force Fμ (as shown in FIG. Figure 5 The second conductive nanowire 124 and the conductive layer 120 are sandwiched by the second conductive nanowire 124 and the conductive layer 120, so that the second conductive nanowire 124 and the conductive layer 120 are more tightly and stably bonded together, without defects such as cracks, ruptures and / or deformations caused by insufficient friction as in the prior art. In addition, based on a similar principle, the second conductive nanowire 124 and the portion of the conductive layer 120 on one side of the first buffer nanocolumn 118A1 are also more tightly and stably bonded together, which will not be repeated here.

[0046] Return to reference Figure 3 and Figure 4 In some embodiments, the side surface of the second conductive nanowire 124 is a rough surface formed by a plurality of conductive wires 124L extending obliquely toward the second pad 122, and the plurality of conductive wires 124L penetrate into the outer conductive wall 120S1 of the conductive layer 120. By penetrating the conductive wires 124L into the outer conductive wall 120S1 of the conductive layer 120, not only the contact area between the second conductive nanowire 124 and the conductive layer 120 can be increased, but also the stability of the bonding between the second conductive nanowire 124 and the conductive layer 120 can be enhanced. Therefore, by penetrating the conductive wires 124L into the outer conductive wall 120S1 of the conductive layer 120, defects such as cracks, deformation and rupture caused by point contact as in the prior art can be further avoided, and the bonding structure 110 can also have better electrical performance. In some embodiments, the plurality of conductive wires 124L and the second conductive nanowire 124 are an integral piece formed of the same conductive material. In the embodiment where the first nanowire structure 116 further includes a second buffer nanorod 118A2 , some of the plurality of conductive wires 124L also penetrate into the second outer conductive wall 120S2 .

[0047] In some embodiments, Figure 4 As shown, the outer conductive wall 120S1 is a flat surface. It is easy to understand that the flat surface is the surface into which the conductive wire 124L penetrates. However, the present application is not limited thereto. Figure 6 Another embodiment of the present application is shown Figure 1 FIG. 1 is an enlarged schematic diagram of a region 112 of a bonding structure 110. Figure 6 In the embodiment shown, the outer conductive wall 120S1 may also include a plurality of conductive wires extending obliquely toward the first pad 114. In the embodiment where the first nanowire structure 116 further includes a second buffer nanorod 118A2, the second outer conductive wall 120S2 may also be Figure 4 The flat surface shown may also include a plurality of conductive lines extending obliquely toward the first pad 114 .

[0048] Return to reference Figure 3 and Figure 4 As shown, in some embodiments, the bonding structure 110 further includes a protective layer 126 surrounding the first pad 114, the second pad 122, the conductive layer 120, and the second conductive nanowire 124, and the protective layer 126 directly contacts the first pad 114, the second pad 122, the conductive layer 120, and the second conductive nanowire 124. In some embodiments, the bonding structure 110 may include a plurality of first nanowire structures 116, each of which includes the first buffer nanopillar 118A1 and the second buffer nanopillar 118A2 as described above, and the conductive layer 120 may conformally and continuously cover the buffer nanopillars of all the first nanowire structures 116. In addition, the bonding structure 110 may further include a plurality of second conductive nanowires 124 disposed on the second pad 122, each of which is located between the conductive layers 120 covering the outer sidewalls of two adjacent buffer nanopillars.

[0049] In some embodiments, Figure 3 As shown, the thickness T1 of the bonding structure 110 may be in the range of 20 um to 250 um, and the thickness T1 of the bonding structure 110 may be equal to the thickness of the protective layer 126. Figure 3 In the cross-sectional view shown, the lateral dimension W1 (eg, width) of the second pad 122 may be in the range of 1 um to 20 um, and the lateral dimension (eg, width) of the first pad 114 may be equal to (or may not be equal to) the lateral dimension (eg, width) of the second pad 122. Figure 4As shown, in some embodiments, the conductive layer 120 is a conductive layer formed of a graphene material. In some embodiments, the second conductive nanowire 124 is a metal nanowire. In the embodiment where the second conductive nanowire 124 is a metal nanowire, the second conductive nanowire 124 may also be referred to as a metal column. In the embodiment where the conductive layer 120 is formed of a graphene material and the second conductive nanowire 124 is formed of a metal (e.g., copper), the bonding of the second conductive nanowire 124 with the conductive layer 120 may be referred to as metal-to-graphene bonding. In some embodiments, the thickness T2 of the conductive layer 120 is in the range of several nanometers to several micrometers. In some embodiments, the first buffer nanocolumn 118A1 and the second buffer nanocolumn 118A2 may be formed of a thermoplastic material (e.g., a thermoplastic resin), the width W2 of the first buffer nanocolumn 118A1 may be in the range of 2um to 50um, the length of the first buffer nanocolumn 118A1 may also be in the range of 2um to 50um, and the width and length of the second buffer nanocolumn 118A2 may be equal to the width W2 and length of the first buffer nanocolumn 118A1, respectively. In some embodiments, the diameter D1 (or width) of the second conductive nanowire 124 is in the range of 2um to 50um, and the length of the second conductive nanowire 124 may also be in the range of 2um to 50um. It is not difficult to understand that the diameter D1 of the second conductive nanowire 124 is the diameter of the portion that does not include the plurality of conductive wires 124L. In some embodiments, the length L1 of the plurality of conductive wires 124L is in the range of several nanometers to several hundred nanometers. In some embodiments, the bonding gap GB of the bonding structure 110 (i.e., the distance between the surface of the first pad 114 provided with the first buffer nanocolumn 118A1 and the surface of the second pad 122 provided with the second conductive nanowire 124) may be in the range of 5um to 200um. Although reference is made to Figure 4 Various size ranges are described, but it will be appreciated that the size ranges above also apply to Figure 6 The embodiment shown.

[0050] According to another aspect of the present application, another bonding structure 110 is provided. Figure 3 and Figure 4The bonding structure 110 includes: a first pad 114, a plurality of buffer nano-pillars 118 extending upward from the first pad 114, a conductive layer 120 covering at least the outer side walls of the plurality of buffer nano-pillars 118, a second pad 122 located above the first pad 114, and a second conductive nano-wire 124 extending downward from the second pad 122, wherein the second conductive nano-wire 124 is located between the conductive layer 120 covering the outer side walls of two adjacent buffer nano-pillars 118. By locating the second conductive nanowire 124 between the conductive layer 120 covering the outer side walls of two adjacent buffer nanopillars 118, since the buffer nanopillar 118 can provide a large pressure between the conductive layer 120 and the second conductive nanowire 124 and can buffer various stresses during the bonding process, this not only makes the conductive layer 120 and the second conductive nanowire 124 in closer contact, but also can avoid defects such as deformation in the conductive layer 120 and the second conductive nanowire 124, so that the conductive layer 120 and the second conductive nanowire 124 can be more stably bonded, and the bonding structure 110 can have better electrical properties. In this embodiment, the buffer nanopillar 118 may include the above-mentioned first buffer nanopillar 118A1 and the second buffer nanopillar 118A2. In some embodiments, the buffer nanopillar 118 is a column formed of a thermoplastic resin. In some embodiments, each adjacent two buffer nanopillars in the plurality of buffer nanopillars 118 are spaced at equal intervals.

[0051] Next reference Figure 3 As shown, in some embodiments, the semiconductor structure 100 further includes a first substrate 136 located below the first pad 114 and a wafer 138 located above the second pad 122. In other embodiments, a wafer may be used to replace the first substrate 136 and / or the wafer 138. The sidewalls of the first substrate 136 and the sidewalls of the wafer 138 are vertically aligned with the sidewalls of the protective layer 126, that is, Figure 3 In the cross-sectional view shown, the lateral dimensions (eg, width) of the protective layer 126 are equal to the lateral dimensions (eg, width) of the substrate 136 and the lateral dimensions (eg, width) of the wafer 138, respectively.

[0052] Figures 7 to 25 Schematic cross-sectional views at various stages of forming a semiconductor structure 200 including a bonding structure 110 according to an embodiment of the present application are shown, wherein: Figures 7 to 13 The lower connection structure 150 including the first pad 114 and the plurality of buffer nano-pillars 118 is shown. Figures 14 to 25 An upper connection structure 170 including a second pad 122 and a plurality of second conductive nanowires 124 is shown formed.

[0053] See also Figure 7, a second substrate 140 is provided, but the present application is not limited thereto, and a wafer or a chip may also be provided, and subsequent processes are performed on the wafer or the chip. Figure 7 As shown, the first pad 114 may be formed on the second substrate 140. In some embodiments, the lateral width of the first pad 114 is smaller than the lateral width of the second substrate 140.

[0054] See next Figure 8 , a thermoplastic film 142 is formed on the second substrate 140 and the first pad 114, and the thermoplastic film 142 covers and contacts the second substrate 140 and the first pad 114. Next, a laser 178 is used to remove a portion of the thermoplastic film 142 to form a plurality of buffer nanorods 118, such as Fig. 9 As shown. The plurality of buffer nanorods 118 may include Figure 4 A first buffer nano-rod 118A1 and a second buffer nano-rod 118A2 are shown.

[0055] See next Fig.10 , a conductive layer 120 is formed by physical vapor deposition (PVD) or coating (as shown by arrow 180 in the figure), and the conductive layer 120 can be a conductive layer formed by graphene. The conductive layer 120 conformally covers the plurality of buffer nanorods 118, the first pad 114 and the second substrate 140. In addition, since graphene has good electrical and thermal conductivity, the conductive layer 120 formed by graphene can make the formed bonding structure have good electrical and thermal conductivity. In some embodiments, the plurality of buffer nanorods 118 can also be referred to as elastic bumps.

[0056] See next Fig.11 , a first photoresist 144 is laminated on the conductive layer 120. Next, the first photoresist 144 is exposed (as shown by arrow 143) and developed to leave a portion of the first photoresist 144 located above the plurality of buffer nanorods 118 and the first pad 114, and to expose a portion of the second substrate 140 not covered by the first pad 114 and a portion of the first pad 114 close to the edge of the first pad 114, see Fig.12 Then, a chemical etchant 146 is used to etch the exposed portion of the conductive layer 120. After the etching is completed, the first photoresist 144 is removed to obtain a lower connection structure 150, as shown in FIG. Fig.13 shown.

[0057] See next Fig.14 , a third substrate 152 is provided, but the present application is not limited thereto, and a wafer or a chip may also be provided, and subsequent processes are performed on the wafer or the chip. Fig.14 As shown, the second pad 122 may be formed on the third substrate 152. In some embodiments, the lateral width of the second pad 122 is smaller than the lateral width of the third substrate 152.

[0058] See next Fig.15 A seed layer 154 is formed on the third substrate 152 and the second pad 122 by physical vapor deposition.

[0059] See next Fig.16 , a second photoresist 156 is laminated on the seed layer 154. Next, the second photoresist 156 is exposed (as shown by arrows 182 in the figure) and developed to form a plurality of openings 158 on the second pad 122, wherein the plurality of openings 158 expose a portion of the seed layer 154, see Fig.17 shown. Fig.17 Also shown is the formation of conductive metal 160 in the plurality of openings 158 by plating. The second photoresist 156 is then removed, and then see Fig.18 , a chemical etchant 162 is used to etch the exposed portion of the seed layer 154 .

[0060] See next Fig.19 After the etching is completed, a plurality of second conductive nanowires 124 are formed, each of which includes a conductive metal 160 and a portion of the seed layer 154. In some embodiments, the second conductive nanowires 124 may also be referred to as metal bumps. Next, a chemical etchant 164 is used to etch the exposed surface of the second conductive nanowire 124, thereby forming a plurality of conductive wires 124L on the surface of the second conductive nanowire 124, thereby forming an upper connection structure 170, such as Fig. 20 shown.

[0061] See next Fig.21 As shown, Fig.13 The lower connecting structure 150 and Fig. 20 The upper connection structure 170 shown is cooled, and the upper connection structure 170 is turned upside down, and then the plurality of second conductive nanowires 124 of the upper connection structure 170 are tilted downward (as shown by arrows 184 in the figure) and inserted between two adjacent buffer nanopillars 118, and the plurality of second conductive nanowires 124 are squeezed between the conductive layer 120 covering the outer side walls of the two adjacent buffer nanopillars 118. In addition, the cooling causes the plurality of second conductive nanowires 124, the buffer nanopillars 118, and the conductive layer 120 to shrink in volume, thereby facilitating the insertion of the plurality of second conductive nanowires 124.

[0062] See next Fig. 22 As shown, Fig. 22The structure shown is heated (as shown by arrow 186 in the figure), so that the second conductive nanowire 124 is better bonded with the conductive layer 120. Specifically, the heating accelerates the mutual diffusion of elements in the second conductive nanowire 124 and the elements in the conductive layer 120, so that the two are better bonded. In addition, the heating also causes the volume expansion of the plurality of second conductive nanowires 124 and the buffer nanocolumns 118 and the conductive layer 120, which makes the elastic force from the buffer nanocolumns 118 and the second conductive nanowires 124 greater, thereby generating a greater friction force between the second conductive nanowires 124 and the conductive layer 120, so as to more stably bond the second conductive nanowires 124 and the conductive layer 120 together, without generating defects such as cracks, ruptures and deformations due to insufficient friction as in the prior art. In addition, the elastic force and friction force generated are Figure 5 The description is similar and will not be repeated here. In this process, since the second conductive nanowire 124 is inserted from top to bottom between two adjacent buffer nanopillars 118, due to the compression of the conductive layer 120, the plurality of conductive wires 124L extending laterally can extend toward the second pad 122. After the heating is completed, the resulting structure is as shown in FIG. Fig.23 shown. Fig.23 The structure in region 172 is Figure 4 The enlarged schematic diagram is similar and will not be repeated here.

[0063] See next Fig.24 As shown, the filling between the second substrate 140 and the third substrate 152 will form Fig.25 The material of the protective layer 126 is shown, while being tilted as Fig.24 The structure shown in FIG. 1 is such that the material of the protective layer 126 flows downward to form the protective layer 126. After the protective layer 126 is formed, the Fig.25 The semiconductor structure 200 shown in FIG. Figure 3 The semiconductor structure 100 is similar to that shown in FIG. 1 , except that the third substrate 152 is not Figure 3 The wafer 138 is shown positioned over the second pad 122 .

[0064] Fig.26 A perspective view of a semiconductor structure 300 according to another embodiment of the present application is shown. The semiconductor structure 300 and Figure 3 The semiconductor structure 100 is similar to that shown, except that Figure 3 Only one wafer 138 is shown. Fig.26 It can be clearly seen that a plurality of wafers 138 arranged in an array may be disposed above the first substrate 136, and the first substrate 136 may have a square shape. However, the present application is not limited thereto, and the first substrate 136 may have a circular shape, such as Fig. 27 At the same time, the joint structure 110 (reference Figure 3The bonding structure 110 may be located between the wafer 138 and the first substrate 136. However, the present application is not limited thereto, and a wafer may be used to replace the first substrate 136. Accordingly, the bonding structure 110 may also be located between the wafer 138 and the wafer. It is not difficult to understand that the bonding structure 110 of the present application may also be located between wafers and wafers, or between substrates and substrates (such as Fig.25 embodiment shown), between the wafer and the substrate, etc.

[0065] The bonding structure provided by the utility model includes a buffer nanocolumn whose outer wall is covered by a conductive layer. Through the buffering effect of the buffer nanocolumn, the bonding structure can at least provide a more stable bonding. In addition, by making the second conductive nanowire located between the conductive layer covering the outer wall of the adjacent buffer nanocolumns, the friction between the second conductive nanowire and the conductive layer is increased, so that the second conductive nanowire and the conductive layer are more tightly and stably bonded together, so that the bonding structure can avoid defects such as cracks, ruptures and deformation caused by insufficient friction, and thus the bonding structure can have better conductive properties. In addition, the side surface of the second conductive nanowire is a rough surface formed by a plurality of conductive wires extending obliquely toward the second pad, and a plurality of conductive wires penetrate the conductive layer, which can not only increase the contact area between the second conductive nanowire and the conductive layer, but also enhance the stability of the bonding between the second conductive nanowire and the conductive layer, so that the bonding structure has better conductivity.

[0066] 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 joining structure, characterized in that: include: a first pad, and A first nanowire structure, the first nanowire structure comprising: A first buffer nanocolumn, disposed on the first pad; and The conductive layer is disposed on the first pad and the first buffer nanocolumn, and the conductive layer covers the outer side wall of the first buffer nanocolumn.

2. The joining structure according to claim 1, characterized in that: Also includes a second pad and a second conductive nanowire, wherein the second pad is disposed above the first pad, and the second conductive nanowire is disposed on the second pad, The portion of the conductive layer covering the outer sidewall of the first buffer nanocolumn is an outer conductive wall, and the side surface of the second conductive nanowire contacts the outer conductive wall.

3. The joining structure according to claim 2, characterized in that: The conductive layer also covers the top surface of the first buffer nanorod.

4. The joining structure according to claim 2, characterized in that: The side surface of the second conductive nanowire is a rough surface formed by a plurality of conductive wires extending obliquely toward the second pad, and the plurality of conductive wires penetrate into the outer conductive wall.

5. The joining structure according to claim 1, characterized in that: The portion of the conductive layer covering the outer side wall of the first buffer nanocolumn is an outer conductive wall, and the outer conductive wall includes a plurality of conductive lines extending obliquely toward the first pad.

6. The joining structure according to claim 1, characterized in that: The first nanowire structure further includes a second buffer nanocolumn, which is disposed on the first pad and is adjacent to and spaced apart from the first buffer nanocolumn. The conductive layer further covers an outer sidewall of the second buffer nanocolumn.

7. The joining structure according to claim 6, characterized in that: Also includes a second pad and a second conductive nanowire, wherein the second pad is disposed above the first pad, and the second conductive nanowire is disposed above the second pad, The second conductive nanowire is located between the conductive layers covering the outer sidewalls of the first buffer nanorod and the second buffer nanorod.

8. The joining structure according to claim 7, characterized in that: The portion of the conductive layer covering the top surface of the first buffer nano-column is in direct contact with the second pad.

9. The joining structure according to claim 7, characterized in that: A portion of the conductive layer directly contacting the first pad is in direct contact with a top surface of the second conductive nanowire.

10. The joining structure according to claim 7, characterized in that: The first buffer nano-column and the second buffer nano-column are elastic columns.

Images