Bonding structure and method for improving bonding interconnection layer failure
By setting up complementary convex bonding patterns on the metal bonding structures on both sides of the bonding interface, the problem of failure of the metal interconnect layer at the bonding interface in the prior art is solved, and a higher metal interconnect reliability is achieved.
Patent Information
- Application Number
- CN202311362280.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-19
- Publication Date
- 2025-04-29
AI Technical Summary
In the existing hybrid bonding process, copper chemical mechanical grinding and plasma surface activation lead to hollowing or disconnection of the metal interconnect layer at the bonding interface, resulting in connection failure during electrical testing.
A complementary multiple convex bonding patterns are arranged on the metal bonding structures of the two medium bonding surfaces, so that they are in a complementary alignment state during pre-bonding, and interspersed and squeezed during annealing due to volume expansion, thereby increasing the bonding area.
It effectively reduces the voids in the metal interconnection layer, improves the reliability of metal interconnection, and avoids connection failure between the entire metal bonding structure.
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Figure CN119905483A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor integrated circuit technology, and in particular to a bonding structure and method for improving the failure of bonding interconnection layers. Background Art
[0002] The existing hybrid bonding process generally involves making two copper metal bonding structures of the same or different sizes for mutual bonding on the upper and lower bonding surfaces, undergoing a copper chemical mechanical polishing process, plasma activating the surface dielectric layer, and then pre-bonding with a bonding machine, and finally completing the metal interconnection process through high-temperature annealing (about 350°C).
[0003] The existing hybrid bonding process will form a process morphology (copper depression) in which the surface of the copper metal bonding structure is lower than the surface of the surrounding medium during copper chemical mechanical polishing, and when the medium is subjected to plasma surface activation, the surface of the copper metal bonding structure is bombarded by plasma, which will also cause a certain loss of copper material in the copper metal bonding structure, resulting in uneven or concave-convex differences between the surfaces of different copper metal bonding structures, which ultimately leads to voids or even disconnections in the metal interconnect layer at the bonding interface, resulting in connection failure during electrical testing. Summary of the invention
[0004] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and provide a bonding structure and method for improving the failure of bonding interconnection layers.
[0005] To achieve the above object, the technical solution of the present invention is as follows:
[0006] The present invention provides a bonding structure for improving the failure of a bonding interconnection layer, comprising:
[0007] Corresponding to the metal bonding structures on the dielectric bonding surfaces on both sides, the surfaces of the metal bonding structures on both sides have a plurality of complementary protruding bonding patterns; the protruding bonding patterns on the metal bonding structures on both sides of the bonding interface are in a complementary alignment state during pre-bonding, and interpenetrate and squeeze each other due to volume expansion during annealing.
[0008] Furthermore, the dielectric bonding surfaces on both sides are respectively formed on a substrate, a dielectric layer is provided on the surface of the substrate, a groove is provided on the surface of the dielectric layer, the groove is filled with the metal bonding structure, the surface of the dielectric layer forms the dielectric bonding surface, and the top surface of the protruding bonding pattern on the metal bonding structure is lower than, equal to or higher than the dielectric bonding surface.
[0009] Furthermore, the plurality of protruding bonding patterns are arranged in a comb-teeth shape, and the comb teeth of the protruding bonding patterns located on both sides of the bonding interface are arranged in a staggered manner to form a complementary structure.
[0010] Furthermore, the size of the comb teeth is smaller than the spacing between adjacent comb teeth.
[0011] Further, the substrate includes a wafer substrate; and / or, the dielectric layer materials on both sides of the bonding interface are the same or different; and / or, the metal bonding structure includes a copper metal bonding structure.
[0012] The present invention also provides a method for improving the failure of bonding interconnection layer, comprising:
[0013] Providing two dielectric bonding surfaces respectively having metal bonding structures; the metal bonding structures on the two dielectric bonding surfaces have a plurality of complementary protruding bonding patterns on their surfaces;
[0014] Aligning the two dielectric bonding surfaces for pre-bonding so that the protruding bonding patterns on the metal bonding structures on both sides of the bonding interface are in a complementary alignment state;
[0015] Annealing is performed to cause the protruding bonding patterns on the metal bonding structure on both sides of the bonding interface to interpenetrate and squeeze each other due to volume expansion.
[0016] Further, the providing of two dielectric bonding surfaces respectively having metal bonding structures specifically includes:
[0017] providing two substrates;
[0018] forming a first dielectric layer on the two substrates respectively;
[0019] forming a groove on the surface of the first dielectric layer, and filling the groove with a first metal;
[0020] Removing excess first metal on the surface of the first dielectric layer outside the groove by planarization to form a first metal bonding pattern in the groove;
[0021] forming a second dielectric layer on the surface of the first dielectric layer to cover the first metal bonding pattern;
[0022] Patterning the second dielectric layer to form a plurality of recessed patterns at positions corresponding to the first metal bonding patterns, stopping on the surface of the first metal bonding patterns, and making the recessed patterns respectively formed on the two substrates complementary to each other;
[0023] The second metal is filled in the recessed pattern, and the excess second metal on the surface of the second dielectric layer outside the recessed pattern is removed by planarization, and a protruding bonding pattern of the second metal is formed on the surface of the first metal bonding pattern. Then, the second dielectric layer between the protruding bonding patterns is removed, and the second dielectric layer at a position other than the first metal bonding pattern is retained, so that the protruding bonding patterns on the two substrates are complementary to each other, and a metal bonding structure composed of the first metal bonding pattern and the protruding bonding pattern is formed, thereby forming two dielectric bonding surfaces each having a metal bonding structure formed by the surface of the second dielectric layer on the two substrates.
[0024] Furthermore, the second dielectric layer is patterned through photolithography and etching processes to form a plurality of the recessed patterns arranged in a comb-tooth shape, so that after the recessed patterns are filled with the second metal, the plurality of protruding bonding patterns of the formed second metal also become correspondingly comb-tooth-shaped, and the comb teeth of the plurality of protruding bonding patterns on the two substrates are arranged in a staggered manner to form a complementary structure, and the size of the comb teeth of the protruding bonding patterns is smaller than the spacing between adjacent comb teeth.
[0025] Furthermore, through a chemical mechanical polishing planarization process, the top surface of the protruding bonding pattern of the formed second metal is made lower than, equal to or higher than the surface of the second dielectric layer; and / or, before pre-bonding, it also includes: performing surface activation treatment on at least one of the two dielectric bonding surfaces.
[0026] Furthermore, the substrate includes a wafer substrate on which a subsequent metal interconnection layer has been fabricated, and the metal bonding structure is connected to the metal interconnection layer; and / or, the first dielectric layer material on the two substrates is the same or different; and / or, the second dielectric layer material is the same or different from the first dielectric layer material; and / or, the second metal is the same or different from the first metal.
[0027] It can be seen from the above technical scheme that the present invention arranges a plurality of protruding bonding patterns that can form complementarity on the surface of the metal bonding structure located on the two dielectric bonding surfaces, so that the protruding bonding patterns on both sides of the bonding interface are in a complementary alignment state during pre-bonding, reducing the gap between each other, and interpenetrating and squeezing each other due to volume expansion during annealing, which can increase the bonding area between the metal bonding structures on both sides. In this way, even if metal loss occurs, it will not cause the connection failure between the entire metal bonding structure, and can reduce the occurrence of voids in the metal interconnection layer. Therefore, it can effectively make up for the problem of voids or even disconnections in the metal interconnection layer at the bonding interface caused by metal loss on the bonding surface due to the grinding process and surface activation process in the previous metal bonding structure, thereby improving the reliability of metal interconnection. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 It is a schematic diagram of a bonding structure for improving the failure of bonding interconnection layer according to a preferred embodiment of the present invention.
[0029] Figure 2 The present invention is a flowchart of a method for improving the failure of bonding interconnection layer according to a preferred embodiment of the present invention.
[0030] Figure 3-Figure 7 A preferred embodiment of the present invention is used Figure 2 Schematic diagram of the process steps for bonding by the method. DETAILED DESCRIPTION
[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the present invention belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.
[0032] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.
[0033] refer to Figure 1 A bonding structure for improving the failure of bonding interconnection layers of the present invention comprises at least one pair of metal bonding structures 12 respectively disposed on two sides of the dielectric bonding surfaces 20. Figure 1 The example shows that three pairs of metal bonding structures 12 are provided on the dielectric bonding surfaces 20 on both sides; each pair of metal bonding structures 12 includes a metal bonding structure 12 located on the upper dielectric bonding surface 20 and another metal bonding structure 12 located on the lower dielectric bonding surface 20.
[0034] The surfaces of the two metal bonding structures 12 (a pair of metal bonding structures 12) located on the upper and lower sides have a plurality of protruding bonding patterns 122 that are complementary in the upper and lower directions. For example, in any pair of metal bonding structures 12, when a protruding bonding pattern 122 is provided at a certain position on the surface of a metal bonding structure 12 located on the upper side, no protruding bonding pattern 122 is provided at the corresponding position on the surface of a metal bonding structure 12 located on the lower side, but two protruding bonding patterns 122 are arranged side by side at a spacing position greater than the size of the protruding bonding pattern 122 on the upper side on both sides of the corresponding position. In other words, the plurality of protruding bonding patterns 122 located on the upper side and the plurality of protruding bonding patterns 122 located on the lower side are arranged in a mutually staggered form, so as to form a complementary structure of alternating concave and convex on the surfaces of the respective metal bonding structures 12.
[0035] In this way, if the protruding bonding patterns 122 on the upper and lower metal bonding structures 12 are close to each other, a mutually plugged matching state will eventually be formed. When the upper and lower dielectric bonding surfaces 20 are bonded, a bonding interface will be formed between the upper and lower dielectric bonding surfaces 20. A pair of metal bonding structures 12 located on the upper and lower sides of the bonding interface are in an aligned state for pre-bonding. At this time, the protruding bonding patterns 122 on each pair of metal bonding structures 12 are in a complementary alignment state during pre-bonding.
[0036] It is understood that before pre-bonding, it is usually necessary to activate at least one side of the dielectric bonding surface 20. For example, plasma can be used to activate the dielectric bonding surface 20. After the activation treatment, the protruding bonding pattern 122 may be partially lost due to plasma bombardment (see Figure 4 ), so that there are uneven top surfaces of the protruding bonding patterns 122 on each metal bonding structure 12. Therefore, when pre-bonding is performed, the protruding bonding patterns 122 on both sides of each pair of metal bonding structures 12 may partially interpenetrate each other, while the top surfaces of other protruding bonding patterns 122 may be on the same plane, or there may be a certain gap between the top surfaces of some protruding bonding patterns 122 in the vertical direction. In any case, since the surfaces of a pair of bonded metal bonding structures 12 are respectively provided with protruding bonding patterns 122 that can form complementary shapes, the structural defects caused by the metal loss caused by the surface activation treatment will be effectively compensated.
[0037] Thus, when high temperature annealing is performed after pre-bonding, the protruding bonding patterns 122 on the upper and lower sides that are complementary to each other will expand in volume and extend toward each other, forming a state of mutual interpenetration and extrusion (refer to Figure 6), thereby significantly increasing the bonding area between the metal bonding structures 12 on both sides, and finally forming a strong connection with multiple surfaces bonded to each other. Therefore, even if local metal loss or high unevenness occurs during the surface activation treatment, it will not affect the effective connection between the entire metal bonding structure 12, and can reduce the occurrence of voids in the metal interconnection layer, thereby successfully eliminating the risk of connection failure of the metal interconnection layer and improving the reliability of the metal interconnection.
[0038] refer to Figure 1 In some embodiments, the dielectric bonding surfaces 20 on the upper and lower sides are respectively formed on a substrate 10. The dielectric layers 11 are respectively provided on the surfaces of the upper and lower substrates 10, and grooves are respectively provided on the surfaces of the two dielectric layers 11, and the metal bonding structures 12 are filled in the grooves. The surface of each dielectric layer 11 forms a dielectric bonding surface 20 located on one side, so that the metal bonding structures 12 are respectively provided on the dielectric bonding surfaces 20 on both sides.
[0039] In some embodiments, the top surface of the protruding bonding pattern 122 on the metal bonding structure 12 on each side is lower than, equal to, or higher than the dielectric bonding surface 20. The first relative height between the top surface of the protruding bonding pattern 122 on the metal bonding structure 12 on the upper side and the dielectric bonding surface 20 on the same side and the second relative height between the top surface of the protruding bonding pattern 122 on the metal bonding structure 12 on the lower side and the dielectric bonding surface 20 on the same side may be different.
[0040] In some embodiments, the plurality of protruding bonding patterns 122 on the metal bonding structure 12 on each side are arranged in a comb-teeth shape, and the comb teeth of the protruding bonding patterns 122 on both sides of the bonding interface are staggered with each other to form a complementary structure.
[0041] Furthermore, the width of the comb teeth of each protruding bonding pattern 122 is smaller than the spacing between adjacent comb teeth, so as to ensure that the comb teeth of each protruding bonding pattern 122 on the upper and lower sides can be interlaced with each other in the vertical direction during bonding.
[0042] In some embodiments, the substrate 10 includes a wafer substrate 10. For example, the substrate 10 includes a wafer substrate 10 on which a post-metal interconnection layer has been fabricated, and the metal bonding structure 12 is connected to the metal interconnection layer.
[0043] In some embodiments, the dielectric layer 11 on both sides of the bonding interface may be made of the same or different materials. For example, the dielectric layer 11 on both sides of the bonding interface may be made of silicon dioxide. Alternatively, the dielectric layer 11 on the upper side of the bonding interface may be made of silicon dioxide, while the dielectric layer 11 on the lower side of the bonding interface may be made of silicon nitride; or, the dielectric layer 11 on the upper side of the bonding interface may be made of silicon nitride, while the dielectric layer 11 on the lower side of the bonding interface may be made of silicon dioxide.
[0044] In some embodiments, the metal bonding structure 12 includes a first metal bonding pattern 121 and a second metal protrusion bonding pattern 122 connected to each other. The first metal bonding pattern 121 is a block structure having a roughly horizontal surface and serves as a cushion layer for the second metal protrusion bonding pattern 122, that is, the first metal bonding pattern 121 is closer to the substrate 10 and is located at the process lower layer of the second metal protrusion bonding pattern 122.
[0045] In some embodiments, the dielectric layer 11 on each side includes a first dielectric layer 111 and a second dielectric layer 112 stacked on each other. The first dielectric layer 111 is closer to the substrate 10 and is located at the process lower layer of the second dielectric layer 112; the surface of the first metal bonding pattern 121 away from the substrate 10 is flush with the surface of the first dielectric layer 111 away from the substrate 10 in the horizontal direction or has a certain relative height difference; the top surface of the second metal protruding bonding pattern 122 away from the substrate 10 is flush with the surface of the second dielectric layer 112 away from the substrate 10 in the horizontal direction or has a certain relative height difference.
[0046] In some embodiments, the materials of the first dielectric layer 111 on the two substrates 10 are the same or different. The materials of the second dielectric layer 112 on the two substrates 10 are the same or different. The material of the second dielectric layer 112 is the same or different from the material of the first dielectric layer 111. For example, the material of the first dielectric layer 111 and the material of the second dielectric layer 112 can be any one of silicon dioxide and silicon nitride.
[0047] In some embodiments, the first metal material on the two substrates 10 is the same or different. The second metal material on the two substrates 10 is the same or different. The second metal material is the same or different from the first metal material.
[0048] In some embodiments, the first metal and the second metal material include copper, that is, the metal bonding structure 12 is a copper metal bonding structure 12 .
[0049] In some embodiments, the first metal material includes copper, and the second metal material includes copper, gold, platinum, or silver.
[0050] A method for improving the failure of bonding interconnection layers of the present invention is further described in detail below through specific implementations and in conjunction with the accompanying drawings.
[0051] refer to Figure 2 A method for improving the failure of a bonding interconnection layer of the present invention comprises the following steps:
[0052] Step S1: providing two dielectric bonding surfaces 20 each having a metal bonding structure 12; the metal bonding structures 12 on the two dielectric bonding surfaces 20 have a plurality of complementary protruding bonding patterns 122 on their surfaces.
[0053] like Figure 3 As shown, one can use, for example Figure 1 The bonding structure for improving the failure of the bonding interconnection layer of the present invention shown above comprises two dielectric bonding surfaces 20 arranged at the upper and lower sides in an aligned state ready for bonding; at least one pair of metal bonding structures 12 are respectively arranged on the two dielectric bonding surfaces 20, for example Figure 3 The three pairs of metal bonding structures 12 are shown as examples, and each pair of metal bonding structures 12 includes a metal bonding structure 12 located on the upper dielectric bonding surface 20, and another metal bonding structure 12 located on the lower dielectric bonding surface 20. The surfaces of the metal bonding structures 12 on the two dielectric bonding surfaces 20 have a plurality of protruding bonding patterns 122 that are complementary in the upper and lower directions.
[0054] The method of providing two dielectric bonding surfaces 20 respectively having metal bonding structures 12 specifically includes:
[0055] Provide two substrates 10, for example two located at Figure 3 ( Figure 1 ) The wafer substrate 10 on both sides of which the post-metal interconnection layer has been completed. It can be understood that Figure 3 ( Figure 1 ) are in an aligned state to be bonded, and are only for the convenience of comparison when explaining the bonding structure for improving the failure of the bonding interconnect layer of the present invention. The dielectric layer 11 and the metal bonding structure 12 respectively present on the two substrates 10 need to be manufactured separately using, for example, CMOS technology.
[0056] First, first dielectric layers 111 are formed on two substrates 10, respectively. For example, a silicon dioxide first dielectric layer 111 is formed on one substrate 10 located on the upper side, and a silicon nitride first dielectric layer 111 is formed on the other substrate 10 located on the lower side.
[0057] Then, grooves are formed on the surfaces of the first dielectric layers 111 of the two substrates 10 respectively, so that the bottoms of the grooves stop on the surface of the metal interconnection layer on the substrate 10, and the grooves are filled with, for example, a first copper metal, so that the copper first metal is connected to the metal interconnection layer on the substrate 10.
[0058] Next, the surface of the first dielectric layer 111 is planarized by a grinding process such as chemical mechanical polishing, in order to remove the excess first metal deposited on the surface of the first dielectric layer 111 outside the trench when the trench is filled, so as to form a first metal bonding pattern 121 in the trench and form a flat surface of the first dielectric layer 111. In this step, the chemical mechanical polishing process can be adjusted so that the exposed surface of the formed first metal bonding pattern 121 is flush with or slightly lower than the surface of the first dielectric layer 111 (of course, it is also possible to be higher).
[0059] Afterwards, a second dielectric layer 112 is continuously formed on the surface of the first dielectric layer 111 to cover the first metal bonding pattern 121. For example, a silicon dioxide second dielectric layer 112 is formed on one substrate 10 located on the upper side, and a silicon nitride second dielectric layer 112 is formed on another substrate 10 located on the lower side.
[0060] Then, the second dielectric layer 112 is patterned through photolithography and etching processes, and a plurality of recessed patterns penetrating the second dielectric layer 112 are formed at positions corresponding to the first metal bonding patterns 121, stopping on the surface of the first metal bonding patterns 121, and through an alignment process, the recessed patterns respectively formed on the two substrates 10 are made complementary to each other (i.e., the recessed patterns on the two substrates 10 are mutually misaligned).
[0061] Next, a second metal such as copper is filled in the recessed patterns on the two substrates 10 to connect the second metal to the surface of the first metal bonding pattern 121, and excess second metal on the surface of the second dielectric layer 112 outside the recessed patterns is removed by planarization such as chemical mechanical polishing, thereby forming a protruding bonding pattern 122 of the second metal in the recessed pattern on the surface of the first metal bonding pattern 121.
[0062] Then, the second dielectric layer 112 between the protruding bonding patterns 122 corresponding to the positions of the first metal bonding patterns 121 is removed by photolithography and etching processes, and the second dielectric layer 112 at positions other than the first metal bonding patterns 121 is retained, so that the protruding bonding patterns 122 formed on the two substrates 10 are also complementary. In this way, a metal bonding structure 12 composed of the first metal bonding pattern 121 and the second metal protruding bonding pattern 122 is formed, thereby forming two dielectric bonding surfaces 20 respectively having the metal bonding structure 12 formed by the surfaces of the second dielectric layers 112 on the two substrates 10. Among them, by adjusting the chemical mechanical polishing process, the top surface of the formed second metal protruding bonding pattern 122 can be flush with the surface of the second dielectric layer 112, slightly lower or slightly higher (refer to the formation process of the conventional metal bonding structure 12PAD).
[0063] Among them, the second dielectric layer 112 is patterned through layout design, photolithography and etching processes to form a plurality of the recessed patterns arranged in a comb-tooth shape, so that after the recessed patterns are filled with the second metal, the plurality of protruding bonding patterns 122 of the formed second metal also become a comb-tooth shape, and the comb teeth of the plurality of protruding bonding patterns 122 on the two substrates 10 are mutually staggered and arranged to form a complementary structure, and the size of the comb teeth of the protruding bonding patterns 122 is smaller than the spacing between adjacent comb teeth. The specific size can be designed according to the bonding accuracy.
[0064] Step S2: aligning the two dielectric bonding surfaces 20 for pre-bonding, so that the protruding bonding patterns 122 on the metal bonding structures 12 on both sides of the bonding interface are in a complementary alignment state.
[0065] like Figure 4 As shown, before the pre-bonding is performed, at least one of the two dielectric bonding surfaces 20 is subjected to surface activation treatment. For example, the surface of the second dielectric layer 112 on one substrate 10 located on the upper side can be activated by plasma bombardment. At this time, since the surfaces of the metal bonding structures 12 on the two substrates 10 are respectively provided with protruding bonding patterns 122 that can form complementary shapes, the defects of the upper metal bonding structure 12 caused by the metal loss caused by the surface activation treatment will be effectively compensated.
[0066] After that, the two substrates 10 after the activation treatment are aligned up and down, that is, the surfaces of the second dielectric layers 112 on the two substrates 10 (the two dielectric bonding surfaces 20) are aligned, so that the protruding bonding patterns 122 on the two metal bonding structures 12 on both sides of the bonding interface are in a complementary alignment state for pre-bonding, as shown in FIG. Figure 5 shown.
[0067] It can be understood that when pre-bonding is performed, based on a certain bonding pressure and the uneven state between the top surfaces of each protruding bonding pattern 122 on the two metal bonding structures 12 on both sides produced after the activation treatment, a certain degree of mutual interlacing can be produced between some of the protruding bonding patterns 122 on both sides of each pair of metal bonding structures 12.
[0068] Step S3: performing annealing so that the protruding bonding patterns 122 on the metal bonding structure 12 on both sides of the bonding interface are mutually interpenetrated and squeezed due to volume expansion.
[0069] like Figure 6As shown, finally, through a normal high-temperature annealing process (e.g., about 350°C), the metal bonding structures 12 located on the upper and lower sides of the bonding interface are heated to expand in volume and move closer to each other; at the same time, the protruding bonding patterns 122 on the metal bonding structures 12 on both sides also intersect and squeeze each other due to volume expansion. Therefore, the bonding surface between the metal bonding structures 12 on the upper and lower sides in this state has changed from a conventional plane shape to a significantly enlarged bonding surface including the top surface, side surface of the protruding bonding pattern 122 and the surface of the first metal bonding pattern 121 located between two adjacent protruding bonding patterns 122, that is, the bonding area between the metal bonding structures 12 on the upper and lower sides is significantly increased, so even if metal loss occurs during the activation process, it will not cause the connection failure between the entire metal bonding structures 12, and can reduce the occurrence of voids in the metal interconnection layer.
[0070] Moreover, the bonding connection between the upper and lower metal bonding structures 12 formed by the complementary structure is similar to the traditional mortise and tenon structure. When the metal expands in volume, it can effectively fill the void between the two metal bonding structures 12, and finally the upper and lower metal bonding structures 12 are basically integrated. Figure 7 As shown. This improves the reliability of the metal interconnection after bonding.
[0071] In summary, the present invention arranges a plurality of protruding bonding patterns 122 that can form complementary shapes on the surface of the metal bonding structure 12 located on the two dielectric bonding surfaces 20, so that the protruding bonding patterns 122 on both sides of the bonding interface can be in a complementary alignment state during pre-bonding, thereby reducing the gap between them, and can increase the bonding area between the metal bonding structures 12 on both sides due to the expansion of volume during annealing. In this way, even if metal loss occurs, it will not cause the connection failure between the entire metal bonding structure 12, and can reduce the occurrence of voids in the metal interconnection layer. Therefore, it can effectively make up for the problem that the metal bonding structure 12 in the past caused by the grinding process and the surface activation process to cause the metal loss on the bonding surface, resulting in voids or even disconnections in the metal interconnection layer at the bonding interface, thereby improving the reliability of the metal interconnection.
[0072] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.
Claims
1. A bonding structure for improving the failure of bonding interconnection layer, characterized in that: include: Corresponding to the metal bonding structures disposed on the dielectric bonding surfaces on both sides, the surfaces of the metal bonding structures on both sides have a plurality of complementary protruding bonding patterns; The protruding bonding patterns on the metal bonding structure on both sides of the bonding interface are in a complementary alignment state during pre-bonding, and interpenetrate and squeeze each other due to volume expansion during annealing.
2. The bonding structure for improving the failure of bonding interconnection layer according to claim 1, characterized in that: The dielectric bonding surfaces on both sides are respectively formed on a substrate, a dielectric layer is provided on the surface of the substrate, a groove is provided on the surface of the dielectric layer, the groove is filled with the metal bonding structure, the surface of the dielectric layer forms the dielectric bonding surface, and the top surface of the protruding bonding pattern on the metal bonding structure is lower than, equal to or higher than the dielectric bonding surface.
3. The bonding structure for improving the failure of bonding interconnection layer according to claim 1, characterized in that: The plurality of protruding bonding patterns are arranged in a comb-teeth shape, and the comb teeth of the protruding bonding patterns on both sides of the bonding interface are arranged in a staggered manner to form a complementary structure.
4. The bonding structure for improving the failure of bonding interconnection layer according to claim 3, characterized in that: The size of the comb teeth is smaller than the interval between adjacent comb teeth.
5. The bonding structure for improving the failure of bonding interconnection layer according to claim 2, characterized in that: The substrate includes a wafer substrate; and / or, the dielectric layer materials on both sides of the bonding interface are the same or different; and / or, the metal bonding structure includes a copper metal bonding structure.
6. A method for improving the failure of bonding interconnection layer, characterized in that: include: providing two dielectric bonding surfaces each having a metal bonding structure; The surfaces of the metal bonding structures on the two dielectric bonding surfaces have a plurality of complementary protruding bonding patterns; Aligning the two dielectric bonding surfaces for pre-bonding so that the protruding bonding patterns on the metal bonding structures on both sides of the bonding interface are in a complementary alignment state; Annealing is performed to cause the protruding bonding patterns on the metal bonding structure on both sides of the bonding interface to interpenetrate and squeeze each other due to volume expansion.
7. The method for improving the failure of bonding interconnection layer according to claim 6, characterized in that: The providing of two dielectric bonding surfaces respectively having metal bonding structures specifically includes: providing two substrates; forming a first dielectric layer on the two substrates respectively; forming a groove on the surface of the first dielectric layer, and filling the groove with a first metal; Removing excess first metal on the surface of the first dielectric layer outside the groove by planarization to form a first metal bonding pattern in the groove; forming a second dielectric layer on the surface of the first dielectric layer to cover the first metal bonding pattern; Patterning the second dielectric layer to form a plurality of recessed patterns at positions corresponding to the first metal bonding patterns, stopping on the surface of the first metal bonding patterns, and making the recessed patterns respectively formed on the two substrates complementary to each other; The second metal is filled in the recessed pattern, and the excess second metal on the surface of the second dielectric layer outside the recessed pattern is removed by planarization, and a protruding bonding pattern of the second metal is formed on the surface of the first metal bonding pattern. Then, the second dielectric layer between the protruding bonding patterns is removed, and the second dielectric layer at a position other than the first metal bonding pattern is retained, so that the protruding bonding patterns on the two substrates are complementary to each other, and a metal bonding structure composed of the first metal bonding pattern and the protruding bonding pattern is formed, thereby forming two dielectric bonding surfaces each having a metal bonding structure formed by the surface of the second dielectric layer on the two substrates.
8. The method for improving the failure of bonding interconnection layer according to claim 7, characterized in that: The second dielectric layer is patterned by photolithography and etching processes to form a plurality of the recessed patterns arranged in a comb-tooth shape, so that after the recessed patterns are filled with the second metal, the plurality of protruding bonding patterns of the formed second metal also become a comb-tooth shape accordingly, and the comb teeth of the plurality of protruding bonding patterns on the two substrates are arranged in a staggered manner to form a complementary structure, and the size of the comb teeth of the protruding bonding patterns is smaller than the spacing between adjacent comb teeth.
9. The method for improving the failure of bonding interconnection layer according to claim 7, characterized in that: Through a chemical mechanical polishing flattening process, the top surface of the protruding bonding pattern of the second metal is formed to be lower than, equal to or higher than the surface of the second dielectric layer; and / or, before pre-bonding, it also includes: performing surface activation treatment on at least one of the two dielectric bonding surfaces.
10. The method for improving the failure of bonding interconnection layer according to claim 7, characterized in that: The substrate comprises a wafer substrate on which a subsequent metal interconnection layer has been fabricated, and the metal bonding structure is connected to the metal interconnection layer; and / or, the first dielectric layer materials on the two substrates are the same or different; and / or, the second dielectric layer material is the same or different from the first dielectric layer material; and / or, the second metal is the same or different from the first metal.