Devices having routing structures in bonding layers - Patents.com

Abstract

A bonding structure is disclosed. The bonding structure may include a first element with a first bonding layer, the first bonding layer having a first contact pad and a routing trace. The routing trace is formed at the same level as the first contact pad. The bonding structure may include a second element with a second bonding layer having a second contact pad. The first bonding layer of the first element and the second bonding layer of the second element are directly bonded such that the first contact pad and the second contact pad are directly bonded without an intervening adhesive.

Description

[Technical field]

[0001] The technical field relates generally to bonding layers, and more particularly to direct bonding layers with routing structures for semiconductor devices.

[0002] [Citation to Related Applications] This application claims priority to U.S. Provisional Patent Application No. 63 / 217,046, filed on June 30, 2021, entitled "ELEMENT WITH ROUTING STRUCTURE IN BONDING LAYER," which is incorporated by reference in its entirety. [Background technology]

[0003] An integrated device package may use a redistribution layer (RDL) (sometimes called surface interconnect) to rewire or route electrical connections (e.g., signal, ground, or power) from one or more integrated device dies to other devices within the package. For example, fan-out redistribution may bring signals outward from fine pitch bond pads of an integrated device die to more widely spaced locations. Fan-in redistribution may reroute signals from peripheral die pads to more centrally located RDL pads. Lines and pads may be made of a conductive material (e.g., metal) and covered with a non-conductive material (insulator), and openings in the insulator over the pads may be filled with, for example, solder, metal bumps, or pillars to allow connections to other devices.

[0004] Another technique for connecting separate electronic elements, e.g., dies, is direct hybrid bonding, whereby both conductive and non-conductive features of an electronic element are directly bonded to conductive and non-conductive features, respectively, of another electronic element. The bonding layer may comprise both conductive and non-conductive features. In some cases, the RDL may serve as the bonding layer for direct hybrid bonding. For example, a metal layer may be evaporated or deposited and patterned on the die to serve as routing lines leading away from the die pads. An insulator is deposited on the lines and patterned with openings, and pads are formed in these openings from another metal layer, e.g., by damascene techniques. The tops of the pads are exposed while the routing lines are buried under the insulator. To achieve the desired flatness for direct bonding, the insulator and pads are finely polished to prepare them for direct bonding to different elements. Summary of the Invention [Problem to be solved by the invention]

[0005] There is a continuing need for improved structures and methods for connecting one electronic component-containing device to another. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a joint structure, a first element having a first bonding layer, the first bonding layer having a first contact pad and a routing trace formed at the same level as the first contact pad; a second element having a second bonding layer having a second contact pad; A bonding structure is provided, characterized in that the first bonding layer of the first element and the second bonding layer of the second element are directly bonded such that the first contact pads and the second contact pads are directly bonded without an intervening adhesive.

[0007] According to another aspect of the present invention, there is provided a joint structure, comprising: a first element having a first bonding layer, the first bonding layer having a first contact pad and a routing trace connected to the first contact pad, the routing trace extending laterally from the first contact pad in the first bonding layer, the routing trace and the first contact pad being made of the same conductive material; a second element having a second bonding layer having a second contact pad; A bonding structure is provided in which the first element and the second element are directly bonded such that the first contact pads and the second contact pads are directly bonded without an intervening adhesive.

[0008] According to yet another aspect of the present invention, there is provided a joint structure, comprising: a first element having a first bonding layer, the first bonding layer having a first contact pad and a routing trace; a second element having a second bonding layer having a second contact pad; A bonding structure is provided, characterized in that the first element and the second element are directly bonded along a bond interface such that the first contact pad and the second contact pad are directly bonded without an intervening adhesive, and the routing trace and the first contact pad are provided along the bond interface.

[0009] According to yet another aspect of the present invention, there is provided a joint structure, comprising: a first element including a first bonding layer having a bonding side and a backside opposite the bonding side and a via layer disposed on the backside of the first bonding layer, the first bonding layer having an elongated conductive feature in electrical contact with two vias in the via layer; a second element having a second bonding layer having conductive features; A bonding structure is provided in which the first element and the second element are directly bonded such that the elongated conductive feature is in contact with the second bonding layer.

[0010] According to yet another aspect of the present invention, there is provided a device having a bonding layer, the device comprising: a first contact pad embedded within the non-conductive material of the bonding layer, a top surface of the first contact pad not covered by the non-conductive material of the bonding layer; a routing trace embedded in the non-conductive material of the bonding layer, a top surface of the routing trace not covered by the non-conductive material of the bonding layer; A device is provided in which the bonding layer is configured for direct bonding to another device without an intervening adhesive.

[0011] According to yet another aspect of the present invention, there is provided a device having a bonding layer, the device comprising: a first contact pad disposed in the bonding layer; a routing trace disposed within the bonding layer; the first contact pads and the routing traces are exposed at a bonding surface of the bonding layer; A device is provided, wherein the bonding surface of the bonding layer is configured for direct bonding to another device without an intervening adhesive.

[0012] According to yet another aspect of the invention, there is provided a method of forming a device configured for direct bonding to another device, the method comprising the steps of: Partially removing a bonding layer of the element from a bonding surface of the bonding layer; providing a conductive material to the removed portions of the bonding layer to form contact pads and routing traces, the routing traces extending laterally from the contact pads in the bonding layer; A method is provided that includes preparing a joining surface for direct bonding.

[0013] According to yet another aspect of the invention, there is provided a method of forming a device configured for direct bonding to another device, the method comprising the steps of: patterning the conductive layer to form contact pads and routing traces; at least partially embedding the contact pads and routing traces in a non-conductive material; and polishing the surfaces of the contact pads, routing traces, and non-conductive material to prepare them for direct bonding.

[0014] According to yet another aspect of the present invention, there is provided a method of forming a joint structure, comprising the steps of: providing a first element with a first bonding layer, the first bonding layer having a non-conductive material, a first contact pad and a routing trace, the routing trace being formed at the same metal level as the first contact pad; A method is provided that includes polishing a surface of the first contact pad, the routing trace, and the non-conductive material to prepare them for direct bonding.

[0015] According to yet another aspect of the present invention, there is provided a joint structure, comprising: a first element having a first bonding surface, the first bonding surface having a first contact pad and a routing trace; a second element having a second bonding surface with a second contact pad; A bonding structure is provided in which the first element and the second element are directly bonded such that the first contact pad and the second contact pad are directly bonded without an intervening adhesive, and the routing trace is in contact with the second bonding surface.

[0016] The detailed description is provided with reference to the accompanying drawings, in which the left-most digit of a reference number identifies the drawing in which the reference number first appears, and in which the same reference number used in different drawings refers to similar or identical items.

[0017] For purposes of this description, the devices and systems depicted in the figures are shown as having a large number of components. Various implementations of the devices and / or systems described herein may include fewer components and remain within the scope of this disclosure. Alternatively, other implementations of the devices and / or systems may include additional components or different combinations of the components described and still fall within the scope of the invention. [Brief description of the drawings]

[0018] [Figure 1A] FIG. 2 is a schematic cross-sectional side view of a first element and a second element before bonding. [Figure 1B] 1 is a schematic cross-sectional side view of a junction structure having a first element and a second element. [Figure 2A] FIG. 2 is a schematic bottom view of device 4 having routing structures in bonding layer 60. [Figure 2B] 2B is a schematic cross-sectional view of the element shown in FIG. 2A taken along the arrows. [Figure 3A] FIG. 2B is an enlarged plan view of a portion of the element shown in FIG. 2A. [Figure 3B] FIG. 3B is a schematic perspective view of a portion of the element shown in FIG. 3A. [Figure 3C] FIG. 2B is an enlarged plan view of another portion of the element shown in FIG. 2A. [Figure 3D] FIG. 3D is a schematic perspective view of a portion of the element shown in FIG. 3C. [Figure 3E] 2B is an enlarged plan view of another portion of the element shown in FIG. 2A. [Figure 3F] FIG. 3F is a schematic perspective view of a portion of the element shown in FIG. 3E. [Figure 4A] 1A-1D illustrate a manufacturing process for forming a device according to one embodiment. [Figure 4B] 1A-1D illustrate a manufacturing process for forming a device according to one embodiment. [Figure 4C] 1A-1D illustrate a manufacturing process for forming a device according to one embodiment. [Figure 4D]1A-1D illustrate a manufacturing process for forming a device according to one embodiment. [Figure 4E] 1A-1D illustrate a manufacturing process for forming a device according to one embodiment. [Figure 4F] FIG. 5 is a schematic plan view of a mask layer used in the manufacturing process of FIGS. 4A to 4E. [Figure 4G] FIG. 5 is a schematic plan view of a mask layer used in the manufacturing process of FIGS. 4A to 4E. [Figure 5A] 2 is a schematic plan view of a mask layer for forming vias in a via layer of a device. FIG. [Figure 5B] 2 is a schematic plan view of a masking layer for forming contact pads and routing structures in a bonding layer of a device. FIG. [Figure 6A] 2A, 3C and 3D before bonding, and an elongated conductive structure of another element. FIG. [Figure 6B] FIG. 6B shows the elongated conductive structure of FIG. 6A after bonding. [Figure 6C] 6B is a schematic cross-sectional side view of a joint structure including the elongated structure of FIG. 6A. [Figure 7A] FIG. 11 is a table showing example dimensions of components in a bonding layer. [Figure 7B] FIG. 7B is a diagram illustrating a schematic arrangement of the dimensions shown in FIG. 7A. [Figure 8A-8B] FIG. 8A is a bottom view of a device having routing structures in a bonding layer according to one embodiment, and FIG. 8B is an enlarged view of a portion of the device shown in FIG. 8A. [Figure 9] FIG. 1 shows an infrared (IR) image at or near the bond interface of a bonded structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Two or more semiconductor elements (e.g., integrated device dies, wafers, etc.) may be bonded together to form a bonded structure. A conductive feature (e.g., a contact pad, an exposed end of a via (e.g., a TSV), or a through-substrate electrode) of one element may be electrically connected to a corresponding conductive feature of the other element. Any suitable number of elements may be stacked within the bonded structure.

[0020] 1A and 1B, in some embodiments, the elements (e.g., a first element 1 and a second element 2) are directly bonded to each other without an intervening adhesive. Alternatively, the redistribution layer (RDL) of one element is directly hybrid bonded to the redistribution layer of the other element. In various embodiments, the non-conductive material 11 of the first element 1 (e.g., a first semiconductor device die with active circuitry or a first integrated device die) may be directly bonded to the corresponding non-conductive material 31 of the second element 2 (e.g., a second semiconductor device die with active circuitry or an interconnect structure) without an adhesive. The non-conductive material 11 may be referred to as the non-conductive bonding region of the first element. The non-conductive material 11 of the first element may be directly bonded to the corresponding non-conductive material 31 of the second element 2 using a dielectric-to-dielectric bonding technique. For example, a dielectric-to-dielectric covalent bond may be formed without an adhesive using a direct bonding technique. Suitable non-conductive bonding materials include conventional insulating materials used in semiconductor processing, including, but not limited to, silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon carbonitride, and the like.

[0021] In various embodiments, direct bonds can be formed without an intervening adhesive. For example, the conductive bonding surfaces can be polished to a high degree of smoothness. The bonding surfaces can be cleaned and exposed to a plasma and / or an etchant to activate the surfaces. In some embodiments, the surfaces can be terminated with chemical species after or during activation (e.g., during a plasma and / or etch process). Without being bound by theory, in some embodiments, the activation process can be performed to break chemical bonds at the bonding surfaces, and the end-grouping process can provide one or more additional chemical species at the bonding surfaces that improve the bonding energy during direct bonding. In some embodiments, activation and end-grouping can be performed in the same step, e.g., a plasma or a wet etchant can activate and end-group the surfaces. In other embodiments, the bonding surfaces can be end-grouped in a separate process to provide additional chemical species for direct bonding. In various embodiments, the end-grouping species can include nitrogen. Additionally, in some embodiments, the bonding surfaces can be exposed to fluorine. For example, one or more fluorine peaks may occur at or near the layers and / or bonding interface. Thus, in a direct bond structure, the bonding interface between two dielectrics may comprise a very smooth interface with high nitrogen content and / or fluorine peaks at the bonding surface. Additional examples of activation and / or end group treatments can be found throughout U.S. Patent Nos. 9,564,414, 9,391,143, and 10,434,749, each of which is incorporated by reference and incorporated herein in its entirety for all purposes.

[0022] In various embodiments, the conductive features of the first component 1 (e.g., the first and second contact pads 16, 18 shown in FIGS. 1A and 1B) may be directly bonded to corresponding conductive features of the second component 2 (e.g., the third and fourth contact pads 36, 38 shown in FIGS. 1A and 1B). For example, hybrid bonding techniques may be used to provide inter-conductor direct bonds along bond interfaces that include covalent direct bond inter-dielectric surfaces that have been pretreated as described above. In various embodiments, inter-conductor (e.g., contact pad-to-contact pad) direct bonds and inter-dielectric hybrid bonds may be formed using direct bonding techniques disclosed at least in U.S. Pat. Nos. 9,716,033 and 9,852,988, each of which is incorporated by reference in its entirety and incorporated herein for all purposes.

[0023] For example, the dielectric bonding surfaces may be pretreated and directly bonded to each other without an intervening adhesive as described above. The conductive contact pads, which may be at least partially surrounded by the non-conductive field regions, may also be directly bonded to each other without an intervening adhesive. In some embodiments, the respective conductive features may be recessed below the outer surface (e.g., top surface) of the dielectric field region or non-conductive bonding region by, for example, less than 20 nm, less than 15 nm, or less than 10 nm, and may be recessed in the range of 2 nm to 20 nm, or in the range of 4 nm to 10 nm. The non-conductive bonding regions may be directly bonded to each other without an adhesive at room temperature in some embodiments, and the bonded structure may then be annealed. During annealing, the conductive features may thermally expand and contact each other, thereby forming a metal-to-metal direct bond. Beneficially, through the use of hybrid direct bonding (Direct Bond Interconnect (DBI®) technology commercially available from Invensas Bonding Technologies, San Jose, Calif.), a high density of conductive features can be connected across a direct bond interface (e.g., at small or fine pitch for regular arrays). In some embodiments, the pitch of the conductive features may be less than 40 microns, less than 10 microns, or even less than 1 micron. For some applications, the ratio of the bond pad pitch to one of the dimensions of the conductive features is less than 5, less than 3, or in some cases desirably less than 2. In various embodiments, the conductive features may be made of copper, although other metals may be suitable.

[0024] Thus, in a direct bonding process, a first element may be directly bonded to a second element without an intervening adhesive. In some configurations, the first element may comprise a singulated element, such as a singulated integrated device die. In other configurations, the first element may comprise a carrier or substrate (e.g., a wafer) that includes a plurality (e.g., tens, hundreds, or more) of device regions that, when singulated, form a plurality of integrated device dies. Similarly, the second element may comprise a singulated element, such as a singulated integrated device die. In other configurations, the second element may comprise a carrier or substrate (e.g., a wafer).

[0025] As described herein, the first and second elements can be directly bonded to each other without adhesive, which is different from a deposition process. Thus, the first and second elements can be composed of non-deposited elements. One skilled in the art can visually distinguish between the direct bond layer and the layer deposited on the element. The direct bond structure can include defect areas along the bond interface where nanovoids exist. The nanovoids can be formed due to activation (e.g., exposure to plasma) of the bonded surfaces. As described above, the bond interface can include a concentration of material resulting from the activation and / or final chemical treatment process. For example, in an embodiment utilizing nitrogen plasma for activation, a nitrogen peak can be formed at the bond interface. In an embodiment utilizing oxygen plasma for activation, an oxygen peak can be formed at the bond interface. The nitrogen peak can be detected using a secondary ion mass spectrometer. In various embodiments, for example, a nitrogen termination treatment (e.g., exposing the bonded layer to a nitrogen-containing plasma) can result in NH 2 -terminated surfaces instead of hydrolyzed (OH-terminated) surfaces. 2Molecules can be used, resulting in a nitrogen-terminated surface. In embodiments utilizing an oxygen plasma for activation, an oxygen peak may form at the bond interface. In some embodiments, the bond interface may be comprised of silicon oxynitride, silicon oxycarbonitride, or silicon carbonitride. As described herein, the direct bond includes a covalent bond, which is stronger than a van der Waals bond. The bonding layer may further include a polished surface that is planarized to a high degree of smoothness.

[0026] In various embodiments, the intermetallic bonds between the conductive features may be bonded such that the copper grains grow into one another across the bond interface. In some embodiments, the copper may have grains oriented along 111 crystal planes to improve diffusion of the copper across the bond interface. The bond interface may extend substantially completely to at least a portion of the bonding conductive feature, such that there are substantially no gaps between the non-conductive bonding regions at or near the bonding conductive feature. In some embodiments, a barrier layer may be provided under the conductive feature (which may, for example, comprise copper). However, in other embodiments, there may not be a barrier layer under the conductive feature, as described, for example, in U.S. Pat. No. 11,195,748, which is incorporated by reference and incorporated herein in its entirety for all purposes.

[0027] FIG. 1A is a schematic cross-sectional side view of a first element 1 and a second element 2 before connecting the first element 1 and the second element 2. FIG. 1B is a schematic cross-sectional side view of a bonding structure 3 including the first element 1 and the second element 2. The first element 1 may have a first bonding layer 10, a first via layer 12, and a routing structure 13. In some embodiments, the routing structure 13 may have multiple layers. For example, the routing structure 13 may have an active layer 14, a routing layer 15, and one or more via layers located between the multiple routing layers. In some embodiments, the routing structure 13 may have a probe pad (not shown) that can be used to test the semiconductor circuit of the first element 1. The first bonding layer 10 may have a non-conductive material 11 and conductive features (first contact pad 16, second contact pad 18, and first routing trace 20). The routing traces 20 may be formed at the same level as the first and second contact pads 16, 18 in the bonding layer 10. The first via layer 12 may have a first via 22 and a second via 24. The first and second contact pads 16, 18, and the first routing traces 20 may be made of the same material. In some embodiments, the first and second contact pads 16, 18, and the first routing traces 20 may be formed simultaneously in a single manufacturing sequence, including a single patterning process. For example, the first and second contact pads 16, 18, and the first routing traces 20 may be formed in a single damascene process using a single mask to pattern and etch voids in the non-conductive material 11 to be filled with conductive material for the contact pads 16, 18, and the first routing traces 20. In another embodiment, a single mask may be used to first pattern the conductive layer to form the contact pads 16, 18 and the first routing trace 20, and then the non-conductive material 11 may be deposited thereover to embed the conductive features.A mask process can be used to pattern and etch a blanket conductive layer, a lift-off mask pattern can be formed followed by conductive material deposition, or a shadow mask can be used to deposit conductive material to form the contact pads 16, 18 and the first routing trace 20. In another embodiment, the first contact pad 16, the second contact pad 18, and the first routing trace 20 can be formed in a single damascene process.

[0028] The bonding surface 10a of the first component 1 is highly polished in preparation for direct bonding. In some embodiments, the roughness of the non-conductive material 11 is less than 15 Å rms. In some embodiments, the roughness of the non-conductive material 11 is less than 10 Å rms. In some embodiments, the roughness of the non-conductive material 11 is less than 5 Å rms. The non-conductive material 11 may further include activation and / or termination signatures for direct bonding as described above, such as fluorine and nitrogen profiles.

[0029] In some embodiments, the first contact pads 16, the second contact pads 18, and the first routing traces 20 may be exposed at the bonding surface 10a of the first bonding layer 10. In some embodiments, the non-conductive material 11, the first contact pads 16, the second contact pads 18, and the first routing traces 20 may be substantially flush with one another at the bonding surface 10a as a result of planarization (e.g., CMP). For example, the top surface of the non-conductive material 11, the top surface of the first contact pads 16, the top surface of the second contact pads 18, and the top surfaces of the first routing traces 20 may be flush with one another such that the top surfaces of the first contact pads 16, the second contact pads 18, and the first routing traces 20 are recessed from the top surface of the non-conductive material 11 by no more than 50 nm, 30 nm, or 20 nm. In some embodiments, the first contact pad 16, the second contact pad 18, and / or the first routing trace 20 may have a thickness that is approximately equal to or similar to the thickness of the bonding layer 10. The thickness of the first contact pad 16 and / or the second contact pad 18 may define the thickness of the bonding layer 10. For example, the first contact pad 16, the second contact pad 18, and / or the first routing trace 20 may penetrate the thickness of the non-conductive material 11 of the first bonding layer 10 and may be flush with one another at a bottom surface that is adjacent to the illustrated first via layer 12. In some embodiments, a portion of the non-conductive material 11 may be located between the first via layer 12 and the first contact pad 16, the second contact pad 18, or the routing trace 20. In another embodiment, the first contact pad 16, the second contact pad 18, and / or the first routing trace 20 may have different thicknesses from one another. For example, the first contact pad 16, the second contact pad 18 may have a thickness that is approximately equal to or similar to the thickness of the bonding layer 10, while the first routing trace 20 may have a thickness that is less than the thickness of the bonding layer 10.

[0030] The surfaces of the conductive features (e.g., first contact pads 16, second contact pads 18, and first routing traces 20) at the bonding surface 10a may vary slightly from being flush with the non-conductive material 11 for several reasons. First, the conductive features may be intentionally recessed from the non-conductive surface by a planarization process, typically by about 1 nm to 20 nm, in preparation for hybrid direct bonding. Additionally, because the first routing traces 20 may be narrower than the contact pads 38, the first routing traces 20 may be differential dished relative to the wider conductive features.

[0031] In some embodiments, the first routing traces 20 may have elongated conductive features with a trace width narrower than the maximum width of the first contact pads 16 and / or the maximum width of the second contact pads 18 (see FIG. 3A). In some other embodiments, the elongated conductive features may be continuous with the first contact pads 16 and the second contact pads 18, formed from the same deposition or conductive layer as the first contact pads 16 and the second contact pads 18. The first routing traces 20 may extend laterally from the first contact pads 16 in the first bonding layer 10. In some embodiments, the first routing traces 20 may connect the first contact pads 16 and the second contact pads 18 to each other. The first routing traces 20 may provide a redistribution layer (RDL) function to the first bonding layer 10.

[0032] In some embodiments, the first via 22 may be electrically connected to the first contact pad 16 and the second via 24 may be electrically connected to the first routing trace 20. For example, the first via 22 may be connected to an electronic circuit provided in the first active layer 14 and the second via 24 may be connected to a different electronic circuit provided in the first active layer 14. In some embodiments, the first via 22 and / or the second via 24 may extend through the thickness of the first via layer 12. For example, the first via 22 and the second via 24 and some portions of the first active layer 14 may be electrically connected through the routing layer 15. The first active layer 14 may have electronic circuits (not shown) implemented in or on the semiconductor material, including transistors and other electronic devices, and may have back end of line (BEOL) metallization layers connecting the devices to each other. In some embodiments, the first via 22 and / or the second via 24 can electrically connect the first contact pad 16 to the electronic circuitry of the first active layer 14. In some embodiments, the via layer 12 can be formed on and in communication with the BEOL (e.g., interconnect, die pad) of the first active layer 14 at the stage where the RDL is typically formed (e.g., at the wafer level prior to dicing or at the reconstructed wafer level). In other embodiments, the via layer can be omitted and the bonding layer contact pad can be directly connected to the BEOL located below the active layer. In some embodiments, the first contact pad 16 can be electrically connected to the second contact pad 18 through the routing trace 20, and the first via 22 can be electrically connected to the first contact pad 16, but the second via 24 directly connecting to the routing trace 20 may not be provided.

[0033] The first element may be configured to be bonded to another element (second element 2). In some embodiments, the second element 2 may have the same or substantially similar structure as the first element 1. The second element 2 may include a second bonding layer 30, a second via layer 32, and a second active layer 34. The second bonding layer 30 may include a non-conductive material 31, a third contact pad 36, a fourth contact pad 38, and a second routing trace 40 extending from the third contact pad 36 but not in contact with the fourth contact pad 38. The second via layer 32 may include a third via 42 and a fourth via 44. In some embodiments, the third contact pad 36, the fourth contact pad 38, and the second routing trace 40 may be exposed on a bonding surface 30a of the second bonding layer 30. In some embodiments, the non-conductive material 31, the third contact pad 36, the fourth contact pad 38 and the second routing trace 40 may be flush with one another on the mating surface 30a. Unless otherwise specified, the components of the second element 2, including the low roughness, surface activation and recession of the conductive features relative to the non-conductive features, may be the same as or generally similar to the same components of the first element 1.

[0034] 1B, the first element 1 and the second element 2 may be bonded along a bonding interface 45 to form a bonding structure 3. In some embodiments, the first element 1 may be directly bonded to the second element 2 such that the first contact pad 16 is directly bonded to the fourth contact pad 36 without an intervening contact agent and / or the second contact pad 18 is directly bonded to the third contact pad 38 without an intervening contact agent. In some embodiments, the non-conductive material 11 of the first bonding layer 10 and the non-conductive material 31 of the second bonding layer 30 may be directly bonded without an intervening adhesive. In some embodiments, the routing trace 20 of the first element 1 may be in direct contact with the non-conductive material 31 of the second element 2, and similarly, the routing trace 40 of the second element 2 may be in direct contact with the non-conductive material 11 of the first element. In some embodiments, due to misalignment of the first element 1 and the second element 2, a portion of the routing trace 20 may be bonded directly to the third contact pad 36 or the fourth contact pad 38, and the routing trace 40 may be bonded directly to the first contact pad 16 or the fifth contact pad 50. In some other embodiments, a portion of the routing trace 20 may be bonded directly to a portion of another routing trace (not shown) exposed at the surface of the second bonding layer 30 of the second element 2.

[0035] The first bonding layer 10 may include a fifth contact pad 50 and the second bonding layer 30 may include a sixth contact pad 52. The fifth contact pad 50 and the sixth contact pad 52 may be directly bonded to each other without an intervening contact. In some embodiments, the second routing trace 40 may extend laterally from the third contact pad 36 in the second bonding layer 30. In some embodiments, the second routing trace 40 may connect the third contact pad 36 and the sixth contact pad 52.

[0036] In some embodiments, the third via 42 may be electrically connected to the sixth contact pad 52 and the fourth via 44 may be electrically connected to the second routing trace 40. In some embodiments, the third via 42 and / or the fourth via 44 may extend through a thickness of the second via layer 32. In some embodiments, the third via 42 and / or the fourth via 44 may electrically connect the sixth contact pad 52 to electrical circuitry of the second active layer 34.

[0037] In some embodiments, the first element 1 and the second element 2 can have additional contact pads and additional routing traces. The built-in routing bonding layer, e.g., the first bonding layer 10 and the second bonding layer 30, including both bond pads and routing traces (first routing trace 20 and second routing trace 40), allows the elements (first element 1 and second element 2) to laterally route or reroute electrical connections in the built-in routing bonding layer without providing additional layers, e.g., separate underlying redistribution (RDL) layers, to route the electrical connections. The built-in routing bonding layer can reduce manufacturing costs, simplify the manufacturing method, and reduce element thickness. In some applications, the built-in routing bonding layer can improve manufacturing yield. Of course, in other embodiments, the advantages of combining routing and bond pads in the same metal layer with the same patterning step can be combined with a routing layer between the illustrated first bonding layer 10 and the first via layer 12, e.g., routing structure 13, and / or additional routing layers (not shown).

[0038] FIG. 2A is a schematic bottom view of a device 4 having routing structures in a bonding layer 60. FIG. 2B is a schematic cross-sectional sectional view of the device 4 shown in FIG. 2A. FIG. 3A is an enlarged plan view of a portion of the device 4 shown in FIG. 2A. FIG. 3B is a schematic perspective view of a portion of the device 4 shown in FIG. 3A. FIG. 3C is an enlarged plan view of another portion of the device 4 shown in FIG. 2A. FIG. 3D is a schematic perspective view of a portion of the device 4 shown in FIG. 3C. FIG. 3E is an enlarged plan view of another portion of the device 4 shown in FIG. 2A. FIG. 3F is a schematic perspective view of a portion of the device 4 shown in FIG. 3E. The bonding layer 60 of the device 4 may include a plurality of contact pads 56 and a plurality of routing traces 58. Unless otherwise specified, the components of FIGS. 2A-3F may be the same as or generally similar to the components of FIGS. 1A and 1B. In the various figures, the plurality of contact pads 56 are shown as circular pads. However, the contact pads 56 may be of any suitable shape, such as rectangular (eg, square) and octagonal.

[0039] 2B, 3A, and 3B, the device 4 may include a non-conductive material 61, a bonding layer 60 including a first contact pad 66, a second contact pad 68, and a routing trace 70, a via layer 62 including a first via 72 and a second via 74, and an active layer 64 including a first circuit component 64a and a second circuit component 64b. The bonding layer 60 may have a bonding surface 60a configured to be bonded to another device. In some embodiments, the bonding surface 60a of the bonding layer 60 may be configured to be bonded to another device such that the first contact pad 66 and the second connection pad 68 are directly bonded to corresponding conductive features (e.g., contact pads) without an intervening contact agent. The non-conductive material 61 may be configured to be directly bonded to a corresponding non-conductive material of the other device.

[0040] In some embodiments, the first via 72 can electrically connect the first contact pad 66 to the first circuit component 64a, and the second via 74 can electrically connect the second contact pad 68 to the second circuit component 64b. The via layer can have any suitable number of vias.

[0041] 3A, the first contact pad 66 has a maximum width w1 and the second contact pad 68 has a maximum width w2. In some embodiments, the widths w1, w2 of the first contact pad 66 and the second contact pad 68 may be the same as or approximately the same as one another. In some embodiments, the routing trace 70 may have an elongated conductive feature with a trace width w3 that is narrower than the width w1 of the first contact pad 16 and / or the width w2 of the second contact pad 68. In some embodiments, the width w1 of the first contact pad 66 and / or the width w2 of the second contact pad 68 may be at least, for example, two times, three times, five times, or ten times the trace width w3 of the routing trace 70.

[0042] 3C and 3D, the bonding layer 60 of the device 4 may have elongated conductive structures that serve as routing traces 80. The routing traces 80 may be configured to electrically connect the devices together through vias 82, 84 that are connected to different portions of the routing traces 80. As described below with reference to FIGS. 6A-6C, such elongated conductive structures may alternatively or additionally serve as contact features in conjunction with elongated conductive structures on opposing directly bonded devices. In some embodiments, the routing traces 80 may have contact portions that may function as contact pads and routing portions that perform routing functions between the vias 82, 84.

[0043] 3E and 3F, the bonding layer 60 of the device 4 may have a contact pad 86, another contact pad 88, and a routing trace 90 extending laterally from the contact pad 86 in the conductive layer 60. The device 4 may have a via 92 connected to a portion of the routing trace 90. The routing trace 90 may perform an RDL function to offset the contact pad 86 relative to the underlying via 92 and the die pad or interconnect it connects to. Although FIGS. 3B and 3F show the traces 70, 90 with their lower surfaces elevated relative to the lower surfaces of the contact pads 66, 68, 86, 88 of the same bonding layer, those skilled in the art will understand from the description of the processing techniques described below that the traces and contact pads may be coplanar with their bottom surfaces opposite each other at the bonding surface 60a. Additionally, the top surfaces of the contact pads 86, 88 may be recessed slightly more than the corresponding traces 70, 90 due to differential dishing of metal features of different dimensions during polishing (e.g., CMP), as will be appreciated by those skilled in the art.

[0044] In various embodiments disclosed herein, the routing structure is shown as an example of a routing structure. However, in some embodiments, the routing structure may comprise other structures capable of laterally routing electrical connections within a bonding layer, such as signal, ground, or power connections. In some embodiments, the routing trace may comprise multiple routing lines or non-straight lines, and such routing traces are not limited to a single straight conductive line or trace.

[0045] Figures 4A-4E illustrate a manufacturing process for forming a device according to one embodiment. Figures 4F and 4G are schematic plan views of first and second mask layers 96, 98 used in the manufacturing process. Unless otherwise specified, the components in Figures 3A-4G may be the same as or substantially similar to components disclosed herein.

[0046] 4A is a schematic cross-sectional side view of a structure having a bonding layer 60 and a via layer 62 at one step in a manufacturing process. Although the dual damascene process is described as simultaneously depositing vias in via layer 62 and traces / pads in bonding layer 60, one skilled in the art will appreciate that the principles and advantages taught herein apply even if the vias in via layer 62 are formed prior to the formation of bonding layer 60.

[0047] In Figure 4A, a first mask layer 96, such as a patterned resist, may be provided on the bonding layer 60. Figure 4B is a schematic cross-sectional side view of a structure having via holes 72a, 74a in another step of the manufacturing process. In Figure 4B, the via holes 72a, 74a may be formed through both the bonding layer 60 and the via layer 62. In some embodiments, the via holes 72a, 74a may be formed by etching.

[0048] Figure 4C is a schematic cross-sectional side view of the structure after removing or modifying the first mask layer 96 and forming a second mask layer 98 over the bonding layer 60. Figure 4D is a schematic cross-sectional side view of the structure having the cavities 66a, 68a, 70a at another step in the fabrication process. In some embodiments, the cavities 66a, 68a, 70a may be formed by etching.

[0049] In FIG. 4E, contact pads 66, 68, routing traces 70, and vias 72, 74 may be formed in cavities 66a, 68a, 70a, respectively. In some embodiments, routing traces 70 have relatively thin lines with the same depth or thickness as contact pads 66, 68. In some embodiments, contact pads 66, 68, routing traces 70, and vias 72, 74 may be provided by providing a conductive material therein, such as copper. For example, the conductive material may be provided by barrier and seed deposition (e.g., by PVD), and copper plating, followed by polishing back the copper bump, as known by damascene processing. In some embodiments, contact pads 66, 68, and routing traces 70 may be formed by a single damascene process on pre-existing vias, or via layer 62 may be omitted. In the illustrated embodiment, a dual damascene process is used to simultaneously fill via holes 72a, 74a defined by a first mask layer 96 (see FIG. 4B). The vias 72 and 74 formed by the dual damascene process may be referred to as dual damascene vias.

[0050] As will be appreciated, in this case, with or without dual damascene processing, and with or without an underlying via layer, the traces 70 and contact pads 66, 68 are made from the same deposition (e.g., barrier / seed deposition PVD and copper plating) and the same metal layer. Furthermore, the patterns of the traces 70 and contact pads 66, 68 are formed by the same mask 98.

[0051] Figure 5A is a schematic plan view of a mask layer 100 for forming vias in a via layer of a device. Figure 5B is a schematic plan view of a mask layer 102 for forming contact pads and routing structures, such as routing traces, in a bonding layer of a device. In some embodiments, mask layer 100 and / or mask layer 102 can be used to form device 4 as shown in Figures 2A-3F. Mask layers 100, 102 can be used in a manufacturing process the same as or similar to that described with reference to Figures 4A-4E.

[0052] Figure 6A shows the elongated conductive structure 80 of the element 4 shown in Figures 2A, 3C and 3D prior to bonding, and the elongated conductive structure 80' of another element. Figure 6B shows the elongated conductive structure 80 and the elongated conductive structure 80' after bonding. Figure 6C is a schematic cross-sectional side view of a bonded structure including the elongated structure 80 and the elongated conductive structure 80'.

[0053] The contact locations 80a of the elongated conductive structure 80 and the contact locations 80'a of the elongated conductive structure 80' may be bonded together. In some embodiments, the contact locations 80a of the elongated conductive structure 80 and the contact locations 80'a of the elongated conductive structure 80' may be bonded directly together without an intervening contact agent. By using the crossing lines as contact pads in the bonding layer, a wide alignment margin is obtained. The elongated conductive structure 80 and / or the elongated conductive structure 80' may be connected to multiple vias as disclosed herein, thereby providing electrical routing between the vias.

[0054] Figure 7A is a table showing example dimensions for contact pad diameter, contact pad pitch, contact pad to contact pad spacing, maximum routing trace width, contact pad to routing trace spacing, contact pad to contact pad spacing to contact pad to routing trace spacing ratio, and via diameter. Figure 7B shows a schematic of where the dimensions shown in Figure 7A are located. In some embodiments, the contact pad diameter, contact pad pitch, contact pad to contact pad spacing, maximum routing trace width, contact pad to routing trace spacing, contact pad to contact pad spacing to contact pad to routing trace spacing ratio, and via diameter may be smaller or larger than the values ​​shown in Figure 7A. For example, the contact pad diameter, contact pad pitch, contact pad-to-contact pad spacing, maximum routing trace width, contact pad-to-routing trace spacing, contact pad-to-contact pad spacing to contact pad-to-routing trace spacing ratio, and via diameter may each be within 1%, 3%, 5%, 10%, or 20% of the values ​​shown in Figure 7A (e.g., the listed values ​​may include values ​​of ±1%, ±3%, ±5%, ±10%, or ±20% of this value). In some embodiments, the contact pad diameter may be on the scale of less than 1 micron. In some embodiments, the via diameter can be in the range of, for example, 0.2 μm to 50 μm, 0.2 μm to 25 μm, 0.2 μm to 10 μm, 0.2 μm to 5 μm, 0.2 μm to 2 μm, 2 μm to 50 μm, 40 μm to 50 μm, or 10 μm to 25 μm. The contact pad pitch can be in the range of, for example, 0.4 μm to 5 μm, 0.4 μm to 2 μm, 0.4 μm to 0.9 μm, 0.6 μm to 5 μm, or 0.8 μm to 2 μm.

[0055] FIG. 8A is a bottom view of a device 6 having routing structures in a bonding layer 60. FIG. 8B is an enlarged view of a portion of the device 6 shown in FIG. 8A. The bonding layer 60 of the device 6 can have a plurality of contact pads 56 and a plurality of routing traces 58. Unless otherwise specified, the components in FIG. 8A and FIG. 8B can be the same as or substantially similar to components disclosed herein. FIG. 8A and FIG. 8B show that the plurality of contact pads 56 can have polygonal (e.g., rectangular or square) pads in some embodiments.

[0056] Figure 9 shows an infrared (IR) image at or near the bonding interface of a bonding structure. As shown in Figure 9, two or more contact pads 56 may be routed into the bonding layer through routing traces 58. Although the routing traces 58 shown in Figure 9 connect adjacent pads 56 to each other, the routing traces 58 may connect remote pads to each other in some embodiments.

[0057] In one aspect, a bonding structure is disclosed. The bonding structure may include a first element with a first bonding layer. The first bonding layer has a first contact pad and a routing trace. The routing trace is formed at the same level as the first contact pad. The bonding structure may include a second element with a second bonding layer having a second contact pad. The first bonding layer of the first element and the second bonding layer of the second element are directly bonded such that the first contact pad and the second contact pad are directly bonded without an intervening adhesive.

[0058] In one embodiment, the first bonding layer further comprises a third contact pad, the second bonding layer further comprises a fourth contact pad, and the third and fourth contact pads may be bonded directly to each other without an intervening adhesive.

[0059] In one embodiment, the routing traces have a maximum trace width that is less than the maximum width of the first contact pads.

[0060] In one embodiment, the routing trace contacts and extends laterally from the first contact pad.

[0061] In one embodiment, the routing trace and the first contact pad are made of the same conductive material.

[0062] In one embodiment, the first element further comprises a first via layer deposited on a side of the bonding layer opposite the second element. The first via layer comprises vias extending through a thickness of the first via layer. The first element may further comprise an electronic circuit. The first via may electrically connect the first contact pad and the electronic circuit. The first element may further comprise a routing structure. The first via may electrically connect the first contact pad and the routing structure. The routing structure may include a redistribution layer.

[0063] In one embodiment, the second bonding layer of the second element further comprises a second routing trace.

[0064] In one embodiment, the thickness of the first contact pad defines the thickness of the first bonding layer.

[0065] In one embodiment, the first element has a plurality of contact pads including the first contact pad, wherein at least one of the plurality of first contact pads has a diameter of less than 5 microns.

[0066] In one aspect, a bonding structure is disclosed. The bonding structure may include a first element with a first bonding layer. The first bonding layer has a first contact pad and a routing trace connected to the first contact pad. The routing trace extends laterally from the first contact pad in the first bonding layer. The routing trace and the first contact pad are made of the same conductive material. The bonding structure may include a second element with a second bonding layer having a second contact pad. The first element and the second element are directly bonded such that the first contact pad and the second contact pad are directly bonded without an intervening adhesive.

[0067] In one aspect, a bonding structure is disclosed. The bonding structure can include a first element with a first bonding layer. The first bonding layer can include a first contact pad and a routing trace. The bonding structure can include a second element with a second bonding layer having a second contact pad. The first element and the second element are directly bonded along a bond interface such that the first contact pad and the second contact pad are directly bonded without an intervening adhesive. The routing trace and the first contact pad are disposed along the bond interface.

[0068] In one embodiment, the routing traces contact the non-conductive material of the second bonding layer.

[0069] In one aspect, a bonding structure is disclosed. The bonding structure can include a first element with a first bonding layer having a bonding side and a backside opposite the bonding side and a via layer deposited on the backside of the first bonding layer. The first bonding layer has an elongated conductive feature in electrical contact with two vias in the via layer. The bonding structure can include a second element with a second bonding layer having the conductive feature. The first element and the second element are directly bonded such that the elongated conductive feature is in contact with the second bonding layer.

[0070] In one embodiment, the elongated conductive feature of the first element is in direct contact with the conductive feature of the second element.

[0071] In one embodiment, the first element has a contact pad connected to the elongated conductive feature, which may be directly bonded to the conductive feature of the second element.

[0072] In one aspect, a device is disclosed having an adhesive layer. The device can have a first contact pad embedded within the non-conductive material of the adhesive layer. A top surface of the first contact pad is not covered by the non-conductive material of the adhesive layer. The device can have a routing trace embedded within the non-conductive material of the adhesive layer. A top surface of the routing trace is not covered by the non-conductive material of the adhesive layer. The adhesive layer is configured to be directly bonded to another device without an intervening adhesive.

[0073] In one embodiment, the routing trace laterally connects the first contact pad and the second contact pad.

[0074] In one embodiment, the routing traces are formed at the same metal level as the first contact pads.

[0075] In one embodiment, the routing traces are made from the same metal layer as the first contact pads.

[0076] In one embodiment, the non-conductive material of the bonding layer has a surface roughness of about 20 Å rms or less. The contact pads and routing traces are recessed below a top surface of the non-conductive material of the bonding layer by about 20 nm or less. The non-conductive material of the bonding layer includes nitrogen and / or fluorine doping agents in an amount suitable for direct bonding to a similar non-conductive material of a second component.

[0077] In one embodiment, a device having a bonding layer is disclosed. The device may have a first contact pad disposed in the bonding layer and a routing trace disposed in the bonding layer. The first contact pad and the routing trace are exposed at a bonding surface of the bonding layer. The bonding surface of the bonding layer is configured to be directly bonded to another device without an intervening adhesive.

[0078] In one embodiment, the routing traces are electrically connected to vias in a via layer disposed below the bonding layer.

[0079] In one embodiment, the routing trace extends from the first contact pad.

[0080] In one embodiment, the routing trace extends between a first contact pad and a second contact pad in the bonding layer.

[0081] In one embodiment, the routing trace extends from the first contact pad.

[0082] In one embodiment, the routing traces have a width that is less than the maximum width of the first contact pads.

[0083] In one aspect, a method of forming a device configured for direct bonding to another device is disclosed. The method may include partially removing a bonding layer of the device from a bonding surface of the bonding layer, providing a conductive material to the removed portion of the bonding layer to form contact pads and routing traces, and preparing the bonding surface for direct bonding. The routing traces extend laterally from the contact pads in the bonding layer.

[0084] In one aspect, a method of forming a device configured to be bonded to another device is disclosed, the method including patterning a conductive material to form contact pads and routing traces, at least partially embedding the contact pads and routing traces in a non-conductive material, and polishing a surface of the contact pads, the routing traces, and the non-conductive material to prepare them for direct bonding.

[0085] In one embodiment, the patterning and filling steps include a damascene process in which a single mask is used to form a cavity pattern of contact pads and routing traces and a conductive layer is deposited into the cavity pattern.

[0086] In one embodiment, the method further comprises patterning via holes in a via layer disposed under the bonding layer using an additional mask. The step of depositing a conductive layer in the cavity pattern may comprise simultaneously filling the via holes in a dual damascene process. The step of depositing a conductive layer may comprise depositing a barrier layer, a seed layer and an electroplated copper layer.

[0087] In one aspect, a method of forming a bonding structure is disclosed. The method may include providing a first component with a first bonding layer. The first bonding layer has a non-conductive material, a first contact pad, and a routing trace. The routing trace is formed at the same metal level as the first contact pad. The method may include polishing a surface of the first contact pad, the routing trace, and the non-conductive material to prepare them for direct bonding.

[0088] In one embodiment, the method further includes providing a second element with a second bonding layer having a second contact pad. The method may further include directly bonding the first element and the second element such that the first contact pad and the second contact pad are directly bonded without an intervening adhesive.

[0089] In one aspect, a bonding structure is disclosed. The bonding structure can include a first element with a first bonding surface. The first bonding surface can include a first contact pad and a routing trace. The bonding structure can include a second element with a second bonding surface having a second contact pad. The first element and the second element are directly bonded such that the first contact pad and the second contact pad are directly bonded without an intervening adhesive. The routing trace is in contact with the second bonding surface.

[0090] In one embodiment, the first mating surface further comprises a third contact pad, the second mating surface further comprises a fourth contact pad, and the third and fourth contact pads are bonded directly to each other without an intervening adhesive.

[0091] In one embodiment, the routing traces have a maximum trace width that is less than the maximum width of the first contact pads.

[0092] In one embodiment, the routing trace contacts and extends laterally from the first contact pad.

[0093] In one embodiment, the routing trace and the first contact pad are made of the same conductive material.

[0094] In one embodiment, the first element further comprises a first via layer. The first via layer may have vias extending through a thickness of the first via layer. The first element may further comprise an electronic circuit. The first via may electrically connect the first contact pad and the electronic circuit. The first element may further comprise a routing structure. The first via may electrically connect the first contact pad and the routing structure. The routing structure may include a redistribution layer.

[0095] In one embodiment, the second bonding surface of the second element may further include a second routing trace.

[0096] In one embodiment, a thickness of the first contact pad is greater than a thickness of the routing trace. The first element has a plurality of contact pads including the first contact pad, and at least one of the plurality of first contact pads has a diameter of less than 5 microns.

[0097] Unless the context clearly requires otherwise, throughout the specification and claims, the terms "comprise", "comprising", "include", "including" and the like are to be construed in an inclusive sense, i.e., "including, but not limited to", as opposed to an exclusive or exhaustive sense. As used generally herein, the term "coupled" means two or more elements that are either directly connected to each other or connected to each other by one or more intermediate elements. Similarly, as used generally herein, the term "coupled" means two or more elements that are either directly connected to each other or connected to each other by one or more intermediate elements. Additionally, the words "herein," "above," "below," and words of similar import as used herein refer to this application as a whole and not to any particular portions of this application. Where the context permits, terms in the above Detailed Description using the singular or plural may also include the plural or singular, respectively. The term "or" in reference to a list of two or more items includes the following interpretations of that term: any of the items in the list, all of the items in the list, and any combination of the items in the list.

[0098] Furthermore, conditional terms used in the specification, particularly "can," "could," "might," "may," "eg," "for example," "such as," and the like, unless expressly specified otherwise or understood otherwise within the context in which they are used, are generally intended to imply that certain embodiments include certain features, elements, and / or conditions and that other embodiments do not include certain features, elements, and / or conditions. Thus, such conditional terms are generally not intended to imply that features, elements, and / or conditions are present in any required manner for one or more embodiments.

[0099] Although certain embodiments have been described, these embodiments are provided by way of example only and are not intended to limit the scope of the invention. Indeed, the novel apparatus, methods, and systems described herein may be embodied in a variety of other forms, and furthermore, various omissions, substitutions, and modifications in the form of the methods and systems described herein may be made without departing from the scope of the invention. For example, although blocks are shown in a given arrangement, alternative embodiments may perform substantially the same functions with different components and / or circuit topologies, and some blocks may be deleted, moved, added, divided, combined, and / or modified. Each of these blocks may be embodied in a wide variety of ways. Any suitable combination of elements and acts of the various embodiments described above may be combined to provide further embodiments. The scope of the invention as set forth in the appended claims and equivalents thereto is intended to include such forms or modifications within the scope and spirit of the invention.

Claims

1. A bonding structure, having a first element with a first bonding layer, the first bonding layer having a first contact pad and a routing trace, the routing trace being formed at the same level as the first contact pad, having a second element with a second bonding layer having a second contact pad, wherein the first bonding layer of the first element and the second bonding layer of the second element are directly bonded such that the first contact pad and the second contact pad are directly bonded without an intervening adhesive. A bonding structure.

2. The bonding structure according to claim 1, wherein the first bonding layer further has a third contact pad.

3. The bonding structure according to claim 2, wherein the second bonding layer further has a fourth contact pad, and the third contact pad and the fourth contact pad are directly bonded to each other without an intervening adhesive.

4. The bonding structure according to claim 1, wherein the routing trace has a maximum trace width narrower than the maximum width of the first contact pad.

5. The bonding structure according to claim 1, wherein the routing trace contacts the first contact pad and extends laterally from the first contact pad.

6. The bonding structure according to claim 1, wherein the routing trace and the first contact pad are made of the same type of conductive material.

7. The first element further has a first via layer deposited on a side of the first bonding layer opposite to the second element, the first via layer having vias extending through the thickness of the first via layer. The bonding structure according to claim 1.

8. The first element further has an electronic circuit, and the first via layer electrically connects the first contact pad and the electronic circuit. The bonding structure according to claim 7.

9. The first element further has a routing structure, and the first via layer electrically connects the first contact pad and the routing structure. The bonding structure according to claim 7.

10. The bonding structure according to claim 9, wherein the routing structure includes a redistribution layer (RDL).

11. The bonding structure according to claim 1, wherein the second bonding layer of the second element further has a second routing trace.

12. The bonding structure according to claim 1, wherein the thickness of the first contact pad determines the thickness of the first bonding layer.

13. The bonding structure according to claim 1, wherein the first element has a plurality of contact pads including a first contact pad, and at least one of the plurality of contact pads has a diameter of less than 5 microns.

14. A bonding structure, comprising a first element having a first bonding layer on a bonding side and a back side opposite to the bonding side, and a via layer adhered to the back side of the first bonding layer, wherein the first bonding layer has an elongated conductive feature in electrical contact with two vias of the via layer. comprising a second element having a second bonding layer with a conductive feature. The bonding structure, wherein the first element and the second element are directly bonded such that the elongated conductive feature is in contact with the second bonding layer.

15. The bonding structure according to claim 14, wherein the elongated conductive feature of the first element is in direct contact with the conductive feature of the second element.

16. The bonding structure according to claim 14, wherein the first element has a contact pad connected to the elongated conductive feature, and the contact pad is directly bonded to the conductive feature of the second element.

17. A bonding structure, comprising a first element having a first bonding surface, the first bonding surface having a first contact pad and a routing trace. comprising a second element having a second bonding surface with a second contact pad. The bonding structure, wherein the first element and the second element are directly bonded such that the first contact pad and the second contact pad are directly bonded without an intervening adhesive, and the routing trace is in contact with the second bonding surface.

18. The bonding structure according to claim 17, wherein the first bonding surface has a third contact pad, the second bonding surface has a fourth contact pad, and the third contact pad and the fourth contact pad are directly bonded to each other without an intervening adhesive.

19. The bonding structure according to claim 17, wherein the routing trace has a maximum trace width narrower than the maximum width of the first contact pad.

20. The bonding structure according to claim 17, wherein the routing trace contacts the first contact pad and extends laterally from the first contact pad.

21. The bonding structure according to claim 17, wherein the routing trace and the first contact pad are made of the same type of conductive material.

22. The joining structure according to claim 17, wherein the first element further has a first via layer, and the first via layer has vias extending through the thickness of the first via layer.

23. The joining structure according to claim 17, wherein the thickness of the first contact pad is greater than the thickness of the routing trace.

24. The first bonding layer of the first element and the second bonding layer of the second element are directly bonded such that the non-conductive material of the first bonding layer and the non-conductive material of the second bonding layer are directly bonded without an intervening adhesive. The joining structure according to claim 1.

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