Bonding structure, method for manufacturing bonding structure, and semiconductor device

Abstract

The application relates to the technical field of semiconductor devices, and provides a bonding structure, a preparation method of the bonding structure and a semiconductor device. The bonding structure comprises a substrate, a barrier layer, a transition layer, a bonding layer and a conductive structure. The substrate has a to-be-bonded part. The barrier layer is arranged on the substrate in a layer-by-layer mode. The surface of the barrier layer far from the substrate is uneven. The transition layer is arranged on the side of the barrier layer far from the substrate in a layer-by-layer mode. The surface of the transition layer far from the substrate is uneven. The bonding layer is arranged on the side of the transition layer far from the substrate in a layer-by-layer mode. The surface of the bonding layer far from the substrate is even. The conductive structure is arranged through the bonding layer, the transition layer and the barrier layer and is electrically connected with the to-be-bonded part. The bonding structure is characterized in that the surface of the barrier layer is uneven, and the transition layer and the bonding layer are arranged on the side of the barrier layer in a layer-by-layer mode in sequence. The contact area between the film layers is increased, the interface bonding force is enhanced, and the film layers are prevented from being delaminated.

Description

Technical Field

[0001] This application relates to the field of semiconductor device technology, and in particular to a bonding structure, a method for preparing the bonding structure, and a semiconductor device. Background Technology

[0002] Bonding processes are key technologies for chip stacking, sensor packaging, and 3D integration. Silicon carbide (NDC) films are widely used as passivation or adhesion layers at bonding interfaces due to their excellent insulation, chemical stability, and compatibility with metal layers. For example, in advanced packaging, NDC films need to form a reliable bonding interface with copper (Cu) electrodes to ensure the stability of electrical connections. However, the reliability of the bonding process is highly dependent on the adhesion strength between the multilayer film structures.

[0003] In related technologies, a low-density carbon transition layer is introduced between the NDC film and the silicon nitride (SiN) etch stop layer to alleviate the difference in thermal expansion coefficients and chemical compatibility between NDC and SiN.

[0004] However, in the above scheme, the carbon content of the NDC film layer and the transition layer cannot achieve an ideal step content change, resulting in insufficient interfacial bonding between the film layers, which in turn leads to delamination between the film layers. Summary of the Invention

[0005] This application provides a bonding structure, a method for preparing the bonding structure, and a semiconductor device to improve the interfacial bonding force between film layers and prevent delamination between film layers.

[0006] In a first aspect, embodiments of this application provide a bonding structure, including:

[0007] The substrate contains the components to be bonded.

[0008] A barrier layer is stacked on the substrate, and the surface of the barrier layer away from the substrate is uneven.

[0009] The transition layer is conformally stacked on the side of the barrier layer away from the substrate, and the surface of the transition layer away from the substrate is uneven.

[0010] The bonding layer is conformally stacked on the side of the transition layer away from the substrate, and the surface of the bonding layer away from the substrate is flush at all points.

[0011] A conductive structure is disposed throughout the bonding layer, transition layer and barrier layer, and is electrically connected to the component to be bonded.

[0012] In the above bonding structure, it is possible to have a barrier layer having multiple first protrusions and multiple first recesses, with the multiple first protrusions and multiple first recesses arranged alternately in sequence along a first direction; the first direction intersects with the thickness direction of the substrate.

[0013] In the above bonding structure, it is possible to achieve a distance a between the center lines of two adjacent first protrusions and / or the center lines of two adjacent first recesses, and a length D extending along the first direction of the substrate; a and D satisfy: a≤D / 10.

[0014] In the above bonding structure, it is possible to achieve that, along the thickness direction of the substrate, the maximum thickness of the first protrusion is H1 and the minimum thickness of the first recess is H2; H1 and H2 satisfy: 1.25≤H1 / H2≤5.

[0015] In the above bonding structure, it is possible for the first protrusion and the first recess to extend in a strip shape along the second direction and to be arranged alternately along the first direction.

[0016] In the above bonding structure, the first protrusion and the first recess extend in a ring shape and are arranged alternately along the direction from the center of the ring to the edge of the ring. The first direction, the second direction, and the thickness direction of the substrate intersect each other.

[0017] In the bonding structure described above, the substrate can have a central region and an edge region. The width of the first protrusion and the first recess located in the central region is greater than the width of the first protrusion and the first recess located in the edge region.

[0018] In the above bonding structure, it is possible to achieve that the thickness of the first protrusion and the first recess located in the central region is less than the thickness of the first protrusion and the first recess located in the edge region.

[0019] Secondly, embodiments of this application provide a method for preparing a bonding structure, used to prepare the bonding structure as described above, comprising:

[0020] A substrate is provided, which has components to be bonded.

[0021] A barrier layer is formed on one side of the substrate, and the surface of the barrier layer on the side away from the substrate is uneven.

[0022] A transition layer is formed on the side of the barrier layer away from the substrate, and the surface of the transition layer on the side away from the substrate is uneven.

[0023] A bonding layer is formed conformally on the side of the barrier layer away from the substrate, and the surface of the bonding layer away from the substrate is flush at all points.

[0024] Conductive structures are formed in the bonding layer, transition layer, and barrier layer, and the conductive structures are electrically connected to the workpiece to be bonded.

[0025] In the above-described method for fabricating the bonding structure, forming the barrier layer can be achieved by heating the substrate with a heater to form the barrier layer. The heater has a first heating structure and a second heating structure, and the first heating structure and the second heating structure have different heating temperatures.

[0026] In the above-mentioned method for preparing the bonding structure, it is possible to have the first heating structure and the second heating structure extend in a ring shape and be alternately arranged along the direction from the center of the ring to the edge of the ring, so that the surface of the barrier layer away from the substrate is uneven.

[0027] In the above-mentioned method for preparing the bonding structure, it is possible to have the first heating structure and the second heating structure extend in a strip shape along the second direction and be alternately arranged along the first direction, so that the surface of the barrier layer away from the substrate is uneven.

[0028] In the above-mentioned method for preparing the bonding structure, the formation of the barrier layer can be achieved by: using a spray structure to provide a reaction medium to form a barrier layer on the surface of the substrate; wherein the spray structure has a second protrusion, a second recess and spray holes, a portion of the spray holes are located in the second protrusion and another portion of the spray holes are located in the second recess, and the spray structure provides the reaction medium through the spray holes.

[0029] The second protrusion and the second recess extend in a ring shape and are alternately arranged in sequence along the direction from the center of the ring to the edge of the ring, so that the surface of the barrier layer away from the substrate is uneven; or, the second protrusion and the second recess extend in a strip shape along the second direction and are alternately arranged in sequence along the first direction, so that the surface of the barrier layer away from the substrate is uneven.

[0030] In the above-mentioned method for preparing the bonding structure, it is possible to achieve the following: the spray hole includes a first spray hole and a second spray hole, the diameter of the first spray hole and the diameter of the second spray hole are not equal; the first spray hole and the second spray hole are arranged in a ring shape and are alternately arranged along the direction from the center of the ring to the edge of the ring; or, the first spray hole and the second spray hole are arranged in a strip shape along the second direction and are alternately arranged along the first direction.

[0031] In the above-described method for preparing the bonded structure, it is possible to achieve that the densities of the first spray hole and the second spray hole are not equal.

[0032] In the above-described method for preparing the bonding structure, it is possible to further include, after forming the bonding layer and before forming the conductive structure:

[0033] Chemical mechanical polishing is used to treat the surface of the bonding layer away from the substrate to make the surface of the bonding layer away from the substrate flush.

[0034] In the above-mentioned method for preparing the bonding structure, it is possible to form a conductive structure, specifically including:

[0035] Channels are formed in the bonding layer, transition layer and barrier layer along the thickness direction of the substrate, and conductive structures are formed in the channels.

[0036] Thirdly, embodiments of this application provide a semiconductor device including at least two of the above-described bonding structures, wherein the bonding layers of the at least two bonding structures are connected in a one-to-one correspondence, and the conductive structures of the at least two bonding structures are electrically connected in a one-to-one correspondence.

[0037] The bonding structure, its fabrication method, and semiconductor device provided in this application include a substrate, a barrier layer, a transition layer, and a bonding layer stacked sequentially. By making the surface of the barrier layer away from the substrate uneven, and by sequentially conformally stacking the transition layer and the bonding layer on the side of the barrier layer away from the substrate, the contact area between the barrier layer and the transition layer, and between the transition layer and the bonding layer, is increased, thereby enhancing the interfacial bonding force between the film layers and preventing delamination between the film layers. Attached Figure Description

[0038] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0039] Figure 1 This is a schematic diagram of a semiconductor device in the prior art;

[0040] Figure 2 A schematic diagram of the bonding structure provided in the embodiments of this application;

[0041] Figure 3 This is a schematic diagram of the barrier layer of the bonding structure provided in the embodiments of this application;

[0042] Figure 4 A flowchart illustrating the method for preparing the bonding structure provided in the embodiments of this application;

[0043] Figure 5 A schematic diagram of the method for preparing the bonding structure provided in the embodiments of this application. Figure 1 ;

[0044] Figure 6 A schematic diagram of the method for preparing the bonding structure provided in the embodiments of this application. Figure 2 ;

[0045] Figure 7 A schematic diagram of the method for preparing the bonding structure provided in the embodiments of this application. Figure 3 ;

[0046] Figure 8A schematic diagram of the method for preparing the bonding structure provided in the embodiments of this application. Figure 4 ;

[0047] Figure 9 A schematic diagram of the method for preparing the bonding structure provided in the embodiments of this application. Figure 5 ;

[0048] Figure 10 A schematic diagram of the structure of the heater provided in the embodiments of this application. Figure 1 ;

[0049] Figure 11 A schematic diagram of the structure of the heater provided in the embodiments of this application. Figure 2 ;

[0050] Figure 12 A schematic diagram of the spray structure provided in the embodiments of this application. Figure 1 ;

[0051] Figure 13 A schematic diagram of the spray structure provided in the embodiments of this application. Figure 2 ;

[0052] Figure 14 A schematic diagram of the spray structure provided in the embodiments of this application. Figure 3 ;

[0053] Figure 15 This is a schematic diagram of the structure of a semiconductor device provided in an embodiment of this application.

[0054] Explanation of reference numerals in the attached figures:

[0055] 10. Bonding structure; 11. Substrate; 12. Barrier layer; 121. First protrusion; 122. First recess; 13. Transition layer; 14. Bonding layer; 15. Conductive structure;

[0056] 20. Heater; 21. First heating structure; 22. Second heating structure;

[0057] 30. Spray structure; 31. Second protrusion; 32. Second recess; 33. First spray hole; 34. Second spray hole;

[0058] 40. Semiconductor devices.

[0059] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0060] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0061] Bonding processes are key technologies for chip stacking, sensor packaging, and 3D integration. Silicon carbide (NDC) films are widely used as passivation or adhesion layers at bonding interfaces due to their excellent insulation, chemical stability, and compatibility with metal layers. For example, in advanced packaging, NDC films need to form a reliable bonding interface with copper (Cu) electrodes to ensure the stability of electrical connections. However, the reliability of the bonding process is highly dependent on the adhesion strength between the multilayer film structures.

[0062] Based on the above scenarios, it can be seen that in related technologies, reference... Figure 1 As shown, a low-density carbon transition layer is introduced between the NDC film and the silicon nitride (SiN) etch stop layer to alleviate the difference in thermal expansion coefficients and chemical compatibility between NDC and SiN. However, the carbon content of the NDC film and the transition layer cannot achieve an ideal stepwise change, resulting in insufficient interfacial bonding between the films and thus delamination.

[0063] In view of this, this application provides a bonding structure, a method for fabricating the bonding structure, and a semiconductor device. The bonding structure includes a substrate, a barrier layer, a transition layer, and a bonding layer stacked sequentially. By making the surface of the barrier layer away from the substrate uneven, and by sequentially conformally stacking the transition layer and the bonding layer on the side of the barrier layer away from the substrate, the contact area between the barrier layer and the transition layer, and between the transition layer and the bonding layer, is increased, thereby enhancing the interfacial bonding force between the film layers and preventing delamination between the film layers.

[0064] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0065] In a first aspect, embodiments of this application provide a bonding structure 10, referring to... Figure 2 As shown, it includes a substrate 11, a barrier layer 12, a transition layer 13, a bonding layer 14, and a conductive structure 15.

[0066] The substrate 11 has the component to be bonded. The substrate 11 serves as the support for the bonding structure 10 and provides the device platform where the component to be bonded resides. Exemplarily, the substrate 11 can be single-crystal silicon, silicon-on-insulator, or a compound semiconductor substrate 11, such as lightly doped P-type silicon, lightly doped N-type silicon, intrinsic silicon, silicon-germanium, germanium, gallium arsenide, or silicon carbide substrate 11. The component to be bonded on the substrate 11 can be a top-layer metal pad in a planar CMOS device, a contact structure corresponding to a field-effect transistor, or an interconnect terminal of a gate-around device; it can also be a pre-formed copper interconnect layer, tungsten contact plug, or cobalt contact structure.

[0067] A barrier layer 12 is stacked on the substrate 11, and the surface of the barrier layer 12 away from the substrate 11 is uneven. The barrier layer 12 is used to prevent the upward diffusion of the lower metal material, block the downward penetration of the upper bonding material, and serve as a basic topography layer for forming the uneven interface. Exemplarily, the material of the barrier layer 12 can be silicon nitride, titanium nitride, tantalum nitride, silicon carbide, aluminum oxide, or a composite layer thereof. In addition, the barrier layer 12 can also serve as an etching stop layer and a stress buffer layer.

[0068] In some embodiments, the barrier layer 12 may also adopt a two-layer or three-layer structure, such as silicon nitride / alumina, titanium nitride / tantalum nitride or silicon carbide / silicon nitride stack.

[0069] In some embodiments, the dielectric barrier layer 12 can be formed by plasma-enhanced chemical vapor deposition (PECVD), while the metal nitride barrier layer 12 can be formed by physical vapor deposition (PVD), reactive sputtering, or atomic layer deposition (ALD).

[0070] In some embodiments, based on the undulations on the surface of the barrier layer 12, nanoscale columnar or groove structures can be further formed on the undulating surface of the barrier layer 12. After the transition layer 13 is formed in a conformal manner, the contact area and mechanical anchoring effect can be further increased, thereby further enhancing the bonding and adhesion between the barrier layer 12 and the transition layer 13.

[0071] A transition layer 13 is conformally stacked on the side of the barrier layer 12 facing away from the substrate 11, and the surface of the transition layer 13 on the side away from the substrate 11 is uneven. The transition layer 13 is used to receive the uneven surface of the barrier layer 12 and provide a surface and material transition adapted to the bonding layer 14. Its carbon content is between that of the barrier layer 12 and the bonding layer 14. The transition layer 13 is disposed between the barrier layer 12 and the bonding layer 14, with its lower surface closely adhering to the uneven contour of the barrier layer 12, and its upper surface maintaining the uneven morphology corresponding to that of the bonding layer 14, thereby forming a large contact area bonding at both interfaces.

[0072] For example, the transition layer 13 may be made of silicon oxide, silicon oxynitride, aluminum oxide, or at least one of titanium, titanium oxide, titanium nitride, tantalum, and tantalum oxide, or a layered combination of silicon oxide / aluminum oxide, silicon oxynitride / hafnium oxide, or titanium / titanium nitride.

[0073] A bonding layer 14 is conformally stacked on the side of the transition layer 13 facing away from the substrate 11, and the surface of the bonding layer 14 facing away from the substrate 11 is flush throughout. The bonding layer 14 provides a direct bonding interface with external chips, wafers, or mating bonding surfaces, and while retaining the bottom interface undulation transfer relationship, it is made flush throughout the surface of the side facing away from the substrate 11. The lower surface of the bonding layer 14 conformally conforms to the uneven morphology of the transition layer 13, and the upper surface is formed into a flat surface after deposition thickening, reflow, self-planarization, or chemical mechanical polishing. The flat surface serves as the contact interface for subsequent bonding.

[0074] For example, the bonding layer 14 may be silicon dioxide, low-temperature silicon oxide, silicon oxynitride, aluminum oxide, or a polymer dielectric layer.

[0075] The conductive structure 15 is disposed through the bonding layer 14, the transition layer 13, and the barrier layer 12, and is electrically connected to the component to be bonded, thereby establishing an electrical signal transmission path on both sides of the bonding interface. The conductive structure 15 can be a single columnar through-hole structure, an array of contact plug structures, or a combination of through-holes and pads. It extends longitudinally through each film layer and contacts the component to be bonded at the bottom. At the top, it can directly contact or indirectly connect to the corresponding conductive terminal on the bonding mating side. The electrical connection interface between the conductive structure 15 and the component to be bonded can be achieved through direct metal contact, silicide contact, or pad contact, such as electrical connection with tungsten contact plugs, copper interconnect pads, cobalt contact areas, or metal silicide layers.

[0076] In some embodiments, a padding dielectric layer or a barrier ring may be locally disposed around the outer periphery of the conductive structure 15. The padding dielectric layer may be silicon oxide, silicon nitride, or aluminum oxide to control the stress and diffusion between the conductive structure 15 and the surrounding dielectric layer.

[0077] In this embodiment, by forming an uneven surface on the side of the barrier layer 12 away from the substrate 11, and by sequentially stacking the transition layer 13 and the bonding layer 14 in a conformal manner, an uneven bonding interface is formed between the barrier layer 12 and the transition layer 13, and between the transition layer 13 and the bonding layer 14. This increases the contact area between the barrier layer 12 and the transition layer 13, and between the transition layer 13 and the bonding layer 14, thereby improving the interfacial bonding force between the film layers, preventing film delamination, and ultimately improving the device yield.

[0078] In some embodiments, a multi-level transition layer 13 material can be used to alleviate the interfacial stress between the barrier layer 12 and the bonding layer 14 by adjusting the thermal expansion coefficient and chemical compatibility of the material step by step.

[0079] As one feasible implementation method, refer to Figure 3 As shown, the barrier layer 12 has a plurality of first protrusions 121 and a plurality of first recesses 122, and the plurality of first protrusions 121 and the plurality of first recesses 122 are arranged alternately in sequence along a first direction; the first direction intersects with the thickness direction of the substrate 11.

[0080] The first protrusion 121 and the first depression 122 can be formed by the difference in deposition rate, and multiple first protrusions 121 and multiple first depressions 122 are arranged alternately in sequence to form a barrier layer 12 with surface undulations, thereby increasing the contact area between the barrier layer 12 and the transition layer 13, thereby improving the interfacial bonding force between the barrier layer 12 and the transition layer 13, and thus dispersing and transferring the interfacial load on the surface contour, reducing the peeling tendency under the action of heat treatment and encapsulation stress and improving the electrical connection stability of the bonding structure 10.

[0081] For example, the first direction can be understood as any direction in a plane perpendicular to the thickness direction of the substrate, referring to... Figure 2 As shown, the thickness direction of the substrate can be the y-direction in the figure, and the first direction can be the x-direction in the figure.

[0082] As one feasible implementation, the distance between the center lines of two adjacent first protrusions 121 and / or the center lines of two adjacent first recesses 122 is a, and the extension length of the substrate 11 along the first direction is D; a and D satisfy: a≤D / 10.

[0083] The relationship between a and D defines the density of undulating units per unit length, causing the surface of the barrier layer 12 to form multiple alternating undulations within a short extension range. A smaller a value and a smaller ratio of D can be interpreted as a smaller undulation period, allowing the transition layer 13 to more fully conformally cover the surface of the barrier layer 12 and retain sufficient interfacial bonding area after the subsequent bonding layer 14 is planarized, thereby increasing the overall adhesion of the film layer and ensuring a stable electrical connection between the conductive structure 15 and the component to be bonded when it penetrates through each layer.

[0084] It is understood that the distance 'a' between the center lines of two adjacent first protrusions 121 and / or the center lines of two adjacent first recesses 122 can satisfy the above relationship, and this embodiment does not make specific limitations on this.

[0085] As one feasible implementation, along the thickness direction of the substrate 11, the maximum thickness of the first protrusion 121 is H1, and the minimum thickness of the first recess 122 is H2; H1 and H2 satisfy: 1.25≤H1 / H2≤5.

[0086] The first protrusion 121 can form a more adequate local fit with the transition layer 13, while the first recess 122 provides morphology accommodation space for conformal deposition and matches the through path of the conductive structure 15. When the ratio of the maximum thickness H1 of the first protrusion 121 to the minimum thickness H2 of the first recess 122 is between 1.25 and 5, sufficient undulating interface can be retained to increase the contact area, while avoiding interface stress concentration or expansion of weak areas caused by excessive undulation.

[0087] For example, the ratio of the maximum thickness H1 of the first protrusion 121 to the minimum thickness H2 of the first recess 122 can be 1.25, 2, 2.5, 3, 4, 5, etc., and any of the above ranges are acceptable. This embodiment does not impose a specific limitation on this. When H1 / H2 is close to 1.25, the interface is relatively smooth; when it is close to 5, the undulations are more significant, but interlayer continuity and process feasibility can still be maintained.

[0088] In one feasible implementation, the first protrusion 121 and the first recess 122 extend in a strip-like shape along the second direction and are arranged alternately along the first direction. In this way, the formed strip-like pattern can match the substrate 11 and the main thermal expansion direction of the film layer, relieve unidirectional tensile or compressive stress, and allow the stress to be released in a single direction.

[0089] In one feasible implementation, the first protrusion 121 and the first recess 122 extend in a ring shape and are arranged alternately along the direction from the center of the ring to the edge of the ring. In this way, the bonding structure 10 can uniformly distribute thermal expansion and contraction, encapsulation stress, and cutting stress in the circumferential direction, thereby improving the structural reliability of the bonding structure 10.

[0090] The first direction, the second direction, and the thickness direction of the substrate 11 intersect each other. For example, the first direction, the second direction, and the thickness direction of the substrate are perpendicular to each other, meaning the second direction can be a direction perpendicular to both the first direction and the thickness direction of the substrate (not shown in the figure). When the first protrusion 121 and the first recess 122 extend in a ring shape, the first direction can also be understood as along the radial direction of the ring.

[0091] In one feasible implementation, the substrate 11 has a central region and an edge region. The width of the first protrusion 121 and the first recess 122 located in the central region is greater than the width of the first protrusion 121 and the first recess 122 located in the edge region.

[0092] The first protrusion 121 and the first recess 122 in the central region can form a larger lateral width, making its surface transition smoother; the first protrusion 121 and the first recess 122 in the edge region can form a smaller lateral width to adapt to the morphological distribution with limited peripheral space. It can be understood that the density of the first protrusion 121 and the first recess 122 in the edge region is greater than that in the central region, which can further increase the contact area of ​​the film layer in the edge region and further enhance the interfacial bonding strength between the film layers in the edge region.

[0093] In one feasible implementation, the thickness of the first protrusion 121 and the first recess 122 located in the central region is less than the thickness of the first protrusion 121 and the first recess 122 located in the edge region. The edge region has a larger thickness to compensate for the interface morphology changes at the periphery, and at the same time to increase the contact area between the film layers in the edge region, thereby enhancing the interfacial bonding strength between the film layers located in the edge region.

[0094] Secondly, embodiments of this application provide a method for preparing a bonding structure, used to prepare the bonding structure 10 as described above, referring to... Figures 4 to 9 As shown, it includes:

[0095] S100: A substrate is provided, which has a component to be bonded. The component to be bonded may be disposed inside the substrate 11 or on its surface.

[0096] After providing substrate 11, refer to Figure 5 As shown, it also includes: S200: forming a barrier layer on one side of the substrate, the surface of the barrier layer away from the substrate being uneven. The uneven surface of the barrier layer 12 can provide a non-planar interface for the formation of subsequent film layers.

[0097] After the barrier layer 12 is formed, refer to Figure 6 As shown, it also includes: S300: A transition layer is formed conformally on the side of the barrier layer away from the substrate, and the surface of the transition layer away from the substrate is uneven. The transition layer 13 is formed conformally so that it covers the undulating contour of the barrier layer 12, and the surface of the transition layer 13 away from the substrate 11 remains uneven.

[0098] After the formation of transition layer 13, refer to Figure 7 As shown, it also includes: S400: A bonding layer is formed conformally on the side of the barrier layer away from the substrate, and the surface of the bonding layer away from the substrate is flush. The barrier layer 12 is also formed conformally, and the surface of the bonding layer 14 away from the substrate 11 is flush to meet the subsequent bonding requirements.

[0099] After forming the bonding layer 14, refer to Figure 9As shown, it also includes: S500: forming a conductive structure in the bonding layer, transition layer, and barrier layer, the conductive structure being electrically connected to the workpiece to be bonded. The conductive structure 15 is configured to be electrically connected to the workpiece to be bonded, so as to realize the electrical connection in the bonding structure 10.

[0100] In this embodiment, the uneven surface formed on the side of the barrier layer 12 away from the substrate 11 provides a non-flat interface substrate for subsequent layers. The transition layer 13 is formed conformally on this undulating morphology, which is beneficial for interlayer bonding. The bonding layer 14 has a flush surface while maintaining coverage, thus balancing internal interface bonding and external bonding flatness. A conductive structure 15 is formed in the bonding layer 14, the transition layer 13, and the barrier layer 12 and is electrically connected to the part to be bonded. This structure satisfies the electrical connection requirements while achieving interlayer bonding, thereby improving the interface stability and conductivity reliability of the bonding structure 10.

[0101] As one feasible implementation method, refer to 10 and Figure 11 As shown, forming the barrier layer 12 includes heating the substrate 11 with a heater 20 to form the barrier layer 12. The heater 20 has a first heating structure 21 and a second heating structure 22, the first heating structure 21 and the second heating structure 22 having different heating temperatures.

[0102] After providing a substrate 11 with the bonding element to be bonded, a heater 20 can be used to heat the substrate 11 and simultaneously deposit a barrier layer 12. Since the deposition rate of the barrier layer 12 varies at different temperatures—specifically, it has a higher deposition rate at higher temperatures and a lower deposition rate at lower temperatures—a first heating structure 21 and a second heating structure 22 are provided in the heater 20. These two structures, through independent temperature control, different heating powers, or different heating regions, create a temperature difference, causing the surface of the substrate 11 to be in a non-uniform thermal field during deposition. This results in a controllable undulating morphology for the barrier layer 12. By controlling the heating temperature difference within a range sufficient to change the local film formation rate and surface migration capability, multiple alternating first protrusions 121 and multiple first recesses 122 can be formed on the side of the barrier layer 12 away from the substrate 11. Exemplarily, the first heating structure 21 and the second heating structure 22 can be heating wires.

[0103] In some embodiments, the temperature of the first heating structure 21 is greater than the temperature of the second heating structure 22. Correspondingly, a first protrusion 121 of the barrier layer 12 can be formed at the first heating structure 21, and a first recess 122 of the barrier layer 12 can be formed at the second heating structure 22. By coordinating the two heating structures, the centerline distance a between adjacent first protrusions 121 or first recesses 122 can satisfy a≤D / 10, where D is the extension length of the substrate 11 along the first direction, and the maximum thickness H1 of the first protrusion 121 and the minimum thickness H2 of the first recess 122 can satisfy 1.25≤H1 / H2≤5, thereby obtaining a stable and repeatable surface undulation of the barrier layer 12.

[0104] It should be noted that the temperature difference between the first heating structure 21 and the second heating structure 22 should not be too large, so as to prevent excessive fluctuations in the density, bonding force or height difference of the barrier layer 12 film.

[0105] As one feasible implementation method, refer to Figure 10 As shown, the first heating structure 21 and the second heating structure 22 extend in a ring shape and are alternately arranged in sequence along the direction from the center of the ring to the edge of the ring, so that the surface of the barrier layer 12 away from the substrate 11 is uneven.

[0106] As one feasible implementation method, refer to Figure 11 As shown, the first heating structure 21 and the second heating structure 22 extend in a strip shape along the second direction and are alternately arranged along the first direction so that the surface of the barrier layer 12 away from the substrate 11 is uneven.

[0107] When forming the barrier layer 12, the first heating structure 21 and the second heating structure 22 of the heater 20 can be used to heat the substrate 11 in sections. The first heating structure 21 and the second heating structure 22 can correspond to different power densities or different set temperatures, so as to form a differentiated thermal field during the heating of the substrate 11. By setting the two heating structures as annular extensions and alternating arrangements from the center of the ring to the edge of the ring, or as strip structures extending along the second direction and alternating arrangements along the first direction, the heat input of different areas on the surface of the substrate 11 can be periodically differentiated, thereby forming a first protrusion 121 and a first depression 122 arranged alternately during the growth or deposition of the barrier layer 12. That is, the first protrusion 121 is formed at the position on the surface of the substrate 11 corresponding to the first heating structure 21, and the first depression 122 is formed at the position on the surface of the substrate 11 corresponding to the second heating structure 22, so that the surface of the barrier layer 12 away from the substrate 11 has an uneven morphology.

[0108] For example, the ring structure is suitable for circular wafers, and the strip structure is suitable for rectangular or substrate arrays arranged along a specific direction. The alternation period of the first heating structure 21 and the second heating structure 22 can be matched according to the size of the substrate 11, the thickness of the barrier layer 12, and the distribution of the components to be bonded, so that the formed undulation size meets the conformal coverage requirements of the subsequent transition layer 13. By coordinating the control of the heating temperature difference and spatial arrangement, surface undulations can be stably formed without changing the main structure of the substrate 11, thereby providing a controllable microstructure basis for subsequent interface bonding, making the interface contact state between the barrier layer 12, the transition layer 13, and the bonding layer 14 more stable, and thus coordinating with the electrical connection requirements after the conductive structure 15 penetrates.

[0109] In some embodiments, the first heating structure 21 and / or the second heating structure 22 can be designed as a serpentine bent structure or a U-shaped nested structure (e.g., Figure 11 And by alternating the first heating structure 21 and / or the second heating structure 22, the temperature can be controlled to form the surface undulation barrier layer 12, while reducing the number of heating structures.

[0110] As one feasible implementation method, refer to Figures 12 to 14 As shown, forming the barrier layer 12 includes: using a spray structure 30 to provide a reaction medium to form the barrier layer 12 on the surface of the substrate 11; wherein the spray structure 30 has a second protrusion 31, a second recess 32 and spray holes, a portion of the spray holes are located in the second protrusion 31 and another portion of the spray holes are located in the second recess 32, and the spray structure 30 provides the reaction medium through the spray holes.

[0111] A spray structure 30 continuously or pulses a reaction medium to the surface of the substrate 11. The reaction medium can be a mixture of a gaseous precursor, a reactant gas, and a carrier gas used to form the barrier layer 12. By forming a second protrusion 31 and a second recess 32 on the surface of the spray structure 30, a height difference is created between the spray structure 30 and the substrate 11 below. The second protrusion 31 is closer to the substrate 11, resulting in a faster growth rate of the barrier layer 12, while the second recess 32 is farther from the substrate 11, resulting in a slower growth rate of the barrier layer 12. Thus, the surface undulations of the barrier layer 12 are formed by the surface undulations of the spray structure 30.

[0112] Reference Figure 12 As shown, the second protrusion 31 and the second recess 32 extend in a ring shape and are alternately arranged along the direction from the center of the ring to the edge of the ring, so that the surface of the barrier layer 12 away from the substrate 11 is uneven; or, refer to Figure 13 As shown, the second protrusion 31 and the second recess 32 extend in a strip shape along the second direction and are alternately arranged along the first direction, so that the surface of the barrier layer 12 away from the substrate 11 is uneven.

[0113] When forming the barrier layer 12, a spray structure 30 is used to supply the reaction medium to the surface of the substrate 11. The second protrusion 31 and the second recess 32 of the spray structure 30 are arranged alternately in a ring or strip direction, which changes the local renewal rate of the reaction medium in the spray chamber and makes the medium flux received at different positions on the surface of the substrate 11 different. As a result, the first protrusion 121 and the first recess 122 of the barrier layer 12, which are arranged in a ring or strip, are formed on the substrate 11. That is, the first protrusion 121 is formed at the position corresponding to the second protrusion 31 on the surface of the substrate 11, and the first recess 122 is formed at the position corresponding to the second recess 32 on the surface of the substrate 11, so that the side of the barrier layer 12 away from the substrate 11 forms an uneven surface morphology.

[0114] As one feasible implementation method, refer to Figure 14 As shown, the spray holes include a first spray hole 33 and a second spray hole 34. The diameters of the first spray hole 33 and the second spray hole 34 are not equal. The first spray hole 33 and the second spray hole 34 are arranged in a ring shape and are alternately arranged along the direction from the center of the ring to the edge of the ring. Alternatively, the first spray hole 33 and the second spray hole 34 are arranged in a strip shape along the second direction and are alternately arranged along the first direction.

[0115] The spray holes can further adjust the amount of medium supplied per unit area and the uniformity of coverage by means of the difference in pore size, the alternating distribution of ring or strip, and the density difference of the first spray hole 33 and the second spray hole 34, so that the distribution of the reaction medium on the surface of the substrate 11 forms a spatial gradient.

[0116] For example, by controlling the orifice diameters to be unequal, such as making the diameter of the first spray orifice 33 larger than that of the second spray orifice 34, the first spray orifice 33 corresponds to a larger flow rate, and the second spray orifice 34 corresponds to a smaller flow rate. Combined with the alternating arrangement from the ring center to the ring edge or in the first direction, the growth rate and densification degree of the barrier layer 12 at different locations can be made different. That is, a first protrusion 121 is formed on the surface of the substrate 11 at the position corresponding to the first spray orifice 33, and a first recess 122 is formed on the surface of the substrate 11 at the position corresponding to the second spray orifice 34, thereby forming a barrier layer 12 with surface undulations on the substrate 11. The orifice diameters of the first spray orifice 33 and the second spray orifice 34 can be set to a range sufficient to form a stable flow rate difference without causing spray blockage.

[0117] As one possible implementation, the densities of the first spray hole 33 and the second spray hole 34 are not equal.

[0118] By adjusting the density difference of the spray holes, the mass supply and coverage uniformity per unit area can be adjusted, creating a spatial gradient in the distribution of the reaction medium on the surface of the substrate 11. For example, in areas with high spray hole density, the medium flow rate is greater, resulting in a faster film formation rate on the substrate 11; conversely, in areas with low spray hole density, the medium flow rate is smaller, resulting in a slower film formation rate on the substrate 11. Therefore, by controlling the density of the spray holes, the surface morphology of the barrier layer 12 formed on the surface of the substrate 11 can also be controlled, thereby increasing the contact area with the transition layer 13, enhancing interfacial adhesion, and preventing interfacial delamination or peeling.

[0119] In some embodiments, the structure of the heater 20, the surface morphology of the spray structure 30, and the size and density of the spray holes can be combined to achieve better control of film undulations. It should be noted that when the above-mentioned structure is combined for control, the alternating shape and arrangement direction of the first heating structure 21 and the second heating structure 22 of the heater 20 and the first protrusion 121 and the first recess 122 of the spray structure 30 must be consistent, and at the same time consistent with the arrangement of the second spray holes 34 of the first spray hole 33.

[0120] In some embodiments, spray holes with dynamically adjustable airflow are integrated into the spray structure 30, for example, by controlling the opening and closing of the holes through an electric valve to control the density of the spray holes, thereby achieving real-time adjustment of the airflow distribution according to the deposition process, and thus better controlling the film undulation.

[0121] As one feasible implementation method, refer to Figure 8 As shown, after the bonding layer 14 is formed and before the conductive structure 15 is formed, the following steps are also included:

[0122] Chemical mechanical polishing is used to treat the surface of the bonding layer 14 away from the substrate 11 so that the surface of the bonding layer 14 away from the substrate 11 is flush.

[0123] After the bonding layer 14 is formed, there is a local thickness difference on the side away from the substrate 11 due to the undulation of the underlying transition layer 13 and barrier layer 12. In this embodiment, chemical mechanical polishing is used to planarize the surface. During the polishing process, a polishing slurry containing oxidant, abrasive and dispersant can be used to continuously remove the material in the high point area under the set load, rotation speed and time conditions, so that the surface height of the bonding layer 14 gradually tends to be uniform.

[0124] In some embodiments, the grinding endpoint can be controlled based on film thickness monitoring, friction coefficient change or surface morphology detection, so that the amount of removal matches the initial thickness of the bonding layer 14, and avoids over-grinding affecting the forming position of the subsequent conductive structure 15.

[0125] By performing chemical mechanical polishing on the side of the bonding layer 14 away from the substrate 11, the surface can be processed into a flush mating surface, so that the subsequently formed conductive structure 15 has stable opening and filling conditions in the vertical direction.

[0126] As one feasible implementation method, a conductive structure 15 is formed, specifically including:

[0127] A channel is formed in the bonding layer 14, the transition layer 13 and the barrier layer 12 along the thickness direction of the substrate 11, and a conductive structure 15 is formed in the channel.

[0128] The through-hole formed along the thickness direction of the substrate 11 provides a continuous filling space for the conductive material. After the conductive structure 15 is formed in the through-hole, it can directly cross the bonding layer 14, the transition layer 13 and the barrier layer 12 to establish a vertical interconnection path, thereby enabling the component to be bonded to achieve a stable electrical connection with the external circuit.

[0129] For example, the channel can be formed by laser drilling, dry etching or a combination of both, sequentially penetrating the bonding layer 14, transition layer 13 and barrier layer 12 along the thickness direction of the substrate 11. The aperture, aspect ratio and array spacing of the channel can be set according to the pad size, interconnect density and current carrying requirements of the component to be bonded.

[0130] After the channels are formed, the inner walls of the channels are cleaned, activated, or blocked. Then, conductive structures 15 are formed in the channels through electroplating, electroless plating, fill deposition, or a combination of blocking and filling. The pretreatment of the inner walls of the channels, combined with the subsequent filling process, can improve the adhesion and filling integrity of the conductive material, reduce voids, breaks, or inclusions, and ensure that the conductive structure 15 remains continuous under heat treatment and mechanical loads, thereby achieving reliable conductivity and long-term stable connection of the bonding structure 10.

[0131] Thirdly, referring to Figure 15 As shown, this application provides a semiconductor device 40, including at least two of the above-described bonding structures 10, with the bonding layers 14 of the at least two bonding structures 10 connected in a one-to-one correspondence, and the conductive structures 15 of the at least two bonding structures 10 electrically connected in a one-to-one correspondence.

[0132] The aforementioned connection method can be understood as hybrid bonding. By setting at least two of the aforementioned bonding structures 10 and connecting the bonding layers 14 of each bonding structure 10 one-to-one, a stable and continuous bonding interface can be formed between the upper and lower chips or wafers. This fully utilizes the synergistic cooperation between the barrier layer 12, the transition layer 13, and the bonding layer 14 to enhance the overall bonding strength. By electrically connecting the conductive structures 15 in each bonding structure 10 one-to-one, the interlayer electrical signal or power transmission path is clear and reliable, thereby avoiding poor contact while achieving high-density three-dimensional interconnection. Therefore, this semiconductor device 40 can maintain high mechanical stability and interface peel resistance, and also helps to improve the conductivity reliability, device yield, and long-term stability after stacking and packaging.

[0133] The various embodiments or implementation methods described in this specification are presented in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0134] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiments may include specific features, structures, or characteristics, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0135] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A bonding structure, characterized in that, include: Substrate (11), having the component to be bonded; A barrier layer (12) is stacked on the substrate (11), and the surface of the barrier layer (12) on the side away from the substrate (11) is uneven; A transition layer (13) is conformally stacked on the side of the barrier layer (12) away from the substrate (11), and the surface of the transition layer (13) away from the substrate (11) is uneven. A bonding layer (14) is conformally stacked on the side of the transition layer (13) away from the substrate (11), and the surface of the bonding layer (14) away from the substrate (11) is flush at all points. A conductive structure (15) is disposed through the bonding layer (14), the transition layer (13) and the barrier layer (12), and is electrically connected to the component to be bonded.

2. The bonding structure according to claim 1, characterized in that, The barrier layer (12) has a plurality of first protrusions (121) and a plurality of first recesses (122), and along the first direction, the plurality of first protrusions (121) and the plurality of first recesses (122) are arranged alternately in sequence; The first direction intersects the thickness direction of the substrate (11).

3. The bonding structure according to claim 2, characterized in that, The distance between the center lines of two adjacent first protrusions (121) and / or the center lines of two adjacent first recesses (122) is a, and the extension length of the substrate (11) along the first direction is D; The condition a and D satisfy: a≤D / 10.

4. The bonding structure according to claim 2, characterized in that, Along the thickness direction of the substrate (11), the maximum thickness of the first protrusion (121) is H1, and the minimum thickness of the first recess (122) is H2. H1 and H2 satisfy the condition: 1.25 ≤ H1 / H2 ≤ 5.

5. The bonding structure according to claim 2, characterized in that, The first protrusion (121) and the first recess (122) extend in a strip shape along the second direction and are arranged alternately along the first direction; Alternatively, the first protrusion (121) and the first recess (122) extend in a ring shape and are arranged alternately along the direction from the center of the ring to the edge of the ring; The first direction, the second direction, and the thickness direction of the substrate (11) intersect each other.

6. The bonding structure according to claim 2, characterized in that, The substrate (11) has a central region and an edge region; The width of the first protrusion (121) and the first recess (122) located in the central region is greater than the width of the first protrusion (121) and the first recess (122) located in the edge region. And / or, the thickness of the first protrusion (121) and the first recess (122) located in the central region is less than the thickness of the first protrusion (121) and the first recess (122) located in the edge region.

7. A method for preparing a bonding structure, used to prepare the bonding structure (10) as described in any one of claims 1-6, characterized in that, include: A substrate (11) is provided, the substrate (11) having a component to be bonded; A barrier layer (12) is formed on one side of the substrate (11), and the surface of the barrier layer (12) on the side away from the substrate (11) is uneven; A transition layer (13) is formed contour-fitted on the side of the barrier layer (12) away from the substrate (11), and the surface of the transition layer (13) away from the substrate (11) is uneven. A bonding layer (14) is formed conformally on the side of the barrier layer (12) away from the substrate (11), and the surface of the bonding layer (14) away from the substrate (11) is flush at all points. A conductive structure (15) is formed in the bonding layer (14), the transition layer (13) and the barrier layer (12), and the conductive structure (15) is electrically connected to the component to be bonded.

8. The method for preparing the bonding structure according to claim 7, characterized in that, Forming the barrier layer (12) includes: The substrate (11) is heated using a heater (20) to form the barrier layer (12). The heater (20) has a first heating structure (21) and a second heating structure (22), and the heating temperatures of the first heating structure (21) and the second heating structure (22) are different.

9. The method for preparing the bonding structure according to claim 8, characterized in that, The first heating structure (21) and the second heating structure (22) extend in a ring shape and are alternately arranged along the direction from the center of the ring to the edge of the ring, so that the surface of the barrier layer (12) away from the substrate (11) is uneven; Alternatively, the first heating structure (21) and the second heating structure (22) extend in a strip shape along the second direction and are alternately arranged along the first direction, so that the surface of the barrier layer (12) away from the substrate (11) is uneven.

10. The method for preparing the bonding structure according to claim 7, characterized in that, Forming the barrier layer (12) includes: A spray structure (30) is used to provide a reaction medium to form the barrier layer (12) on the surface of the substrate (11); wherein the spray structure (30) has a second protrusion (31), a second recess (32) and spray holes, a portion of the spray holes being located in the second protrusion (31) and another portion of the spray holes being located in the second recess (32), and the spray structure (30) provides the reaction medium through the spray holes; The second protrusion (31) and the second recess (32) extend in a ring shape and are alternately arranged in sequence along the direction from the center of the ring to the edge of the ring, so that the surface of the barrier layer (12) away from the substrate (11) is uneven; or, the second protrusion (31) and the second recess (32) extend in a strip shape along the second direction and are alternately arranged in sequence along the first direction, so that the surface of the barrier layer (12) away from the substrate (11) is uneven.

11. The method for preparing the bonding structure according to claim 10, characterized in that, The spray holes include a first spray hole (33) and a second spray hole (34), the diameter of the first spray hole (33) and the diameter of the second spray hole (34) are not equal; the first spray hole (33) and the second spray hole (34) are arranged in a ring shape and are alternately arranged along the direction from the center of the ring to the edge of the ring; or, the first spray hole (33) and the second spray hole (34) are arranged in a strip shape along the second direction and are alternately arranged along the first direction.

12. The method for preparing the bonding structure according to claim 11, characterized in that, The densities of the first spray hole (33) and the second spray hole (34) are not equal.

13. The method for preparing the bonding structure according to claim 7, characterized in that, After the bonding layer (14) is formed and before the conductive structure (15) is formed, the method further includes: The surface of the bonding layer (14) away from the substrate (11) is treated with chemical mechanical polishing to make the surface of the bonding layer (14) away from the substrate (11) flush.

14. The method for preparing the bonding structure according to claim 7, characterized in that, Forming the conductive structure (15) specifically includes: A channel is formed in the bonding layer (14), the transition layer (13) and the barrier layer (12) along the thickness direction of the substrate (11), and the conductive structure (15) is formed in the channel.

15. A semiconductor device, characterized in that, It includes at least two bonding structures (10) as described in any one of claims 1-6, wherein the bonding layers (14) of the at least two bonding structures (10) are connected in a one-to-one correspondence, and the conductive structures (15) of the at least two bonding structures (10) are electrically connected in a one-to-one correspondence.

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