Method of bonding copper members and method of bonding dielectric layers

Abstract

To provide a method of bonding copper members and a method of bonding dielectric layers, with which a bonding structure of copper / noble metal / copper with better strength and quality is obtained to improve the bonding effect of the dielectric layers, and in addition, a heat accumulation problem in products is improved, oxides on surfaces are reduced, and copper atom diffusion is improved.SOLUTION: A method of bonding copper members includes the steps of: oxidizing a first copper member to form a first copper oxide structure on a surface of the first copper member, and oxidizing a second copper member to form a second copper oxide structure on a surface of the second copper member; immersing the first copper member and the second copper member into a reaction solution containing noble metal ions to cause a galvanic reaction, so that the first copper oxide structure is replaced with a first noble metal oxide structure, and the second copper oxide structure is replaced with a second noble metal oxide structure; and bonding the first noble metal oxide structure and the second noble metal oxide structure at 25-500°C to connect the first copper member with the second copper member.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a bonding method, and more particularly to a bonding method for copper members and a bonding method for dielectric layers. [Background technology]

[0002] One technique for wafer bonding is the copper-copper hybrid bonding technique, which is a technique in which metal wiring layers containing copper and a dielectric are fabricated on two wafers that are primarily prepared for bonding. The dielectric may be silica or other polymeric material, and the copper may be provided on the surface of the dielectric by vapor deposition.

[0003] The process of copper-copper hybrid bonding technology mainly involves chemically and mechanically polishing (CMP) the above-mentioned metal wiring layer and cleaning it, then aligning the two wafers facing each other, and during bonding, aligning the copper metal with the copper metal and the dielectric with the dielectric, making the shapes and positions at the bonding interface of the two wafers completely identical, and the copper ion layers of the two wafers diffuse into each other and enter the other wafer to form a permanent adhesive bond.

[0004] However, when the copper surface is ground or polished and exposed to the air, it naturally oxidizes to form copper oxides such as copper oxide or cuprous oxide. The copper oxides thicken during the bonding temperature rise process and inhibit the diffusion of copper atoms, resulting in a low bonding effect and affecting the performance, yield and reliability of the product.

[0005] For these reasons, there is a need to improve the conventional method for joining copper members. Summary of the Invention [Problem to be solved by the invention]

[0006] The main object of the present invention is to provide a method for joining copper members in order to solve the technical problem that the joining effect decreases due to natural oxidation after polishing and grinding of the copper surface. [Means for solving the problem]

[0007] In order to achieve the above object, according to one embodiment of the present invention, there is provided a method for joining copper members, comprising: step S11 of oxidizing a first copper member to form a first copper oxide structure on a surface of the first copper member and oxidizing a second copper member to form a second copper oxide structure on a surface of the second copper member; step S12 of immersing the first copper member including the first copper oxide structure and the second copper member including the second copper oxide structure in a reaction solution containing precious metal ions to cause a galvanic reaction, thereby replacing the first copper oxide structure with a first precious metal oxide structure and replacing the second copper oxide structure with a second precious metal oxide structure; and step S13 of directly contacting and joining the first copper member and the second copper member at 25°C to 500°C to connect the first copper member and the second copper member.

[0008] In one embodiment of the present invention, the method further includes, before step S11, performing a chemical mechanical polishing (CMP) process on the first copper member and the second copper member at step S10.

[0009] In one embodiment of the invention, the precious metal ions are selected from the group consisting of silver, gold, ruthenium, rhodium, palladium, platinum and iridium.

[0010] In order to achieve the above object, according to another embodiment of the present invention, there is provided a method for bonding dielectric layers, comprising: step S21 of oxidizing a first copper layer on a surface of a first dielectric layer to form a first copper oxide structure on the surface of the first copper layer and oxidizing a second copper layer on a surface of a second dielectric layer to form a second copper oxide structure on the surface of the second copper layer; step S22 of immersing the first copper layer including the first copper oxide structure and the second copper layer including the second copper oxide structure in a reaction solution containing a precious metal ion to cause a galvanic reaction, thereby replacing the first copper oxide structure with a first precious metal oxide structure and replacing the second copper oxide structure with a second precious metal oxide structure; and step S23 of directly contacting and bonding the first precious metal oxide structure and the second precious metal oxide structure at 25°C to 500°C to connect the first dielectric layer and the second dielectric layer.

[0011] In one embodiment of the present invention, the method further includes, before step S21, performing a chemical mechanical polishing (CMP) process on the first copper layer and the second copper layer in step S20.

[0012] In one embodiment of the invention, the precious metal ions are selected from the group consisting of silver, gold, ruthenium, rhodium, palladium, platinum and iridium.

[0013] In one embodiment of the invention, the first copper layer is formed on the surface of the first dielectric layer by vapor deposition, and the second copper layer is formed on the surface of the second dielectric layer by vapor deposition. Effect of the Invention

[0014] The beneficial effects of the present invention are as follows: by replacing copper oxide with precious metal oxide, the property of precious metal oxide decomposing automatically at high temperature in the atmosphere is utilized to spontaneously remove oxygen from precious metal oxide, and finally obtain a copper / precious metal / copper bonding structure with better strength and quality, and further improve the bonding effect of the dielectric layer; and by further lowering the bonding temperature based on the decomposition temperature and diffusion kinetics of oxide, the problem of heat deposition of the product can be improved, the surface oxide can be reduced, and the diffusion of copper atoms can be improved. [Brief description of the drawings]

[0015] [Figure 1] 2 is a flowchart of a method for joining copper members according to an embodiment of the present invention. [Diagram 2] 2 is a flowchart of a method for bonding dielectric layers according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a schematic diagram showing a method for bonding dielectric layers according to an embodiment of the present invention, in which copper contacts are vapor-deposited on the dielectric layers. [Figure 4] FIG. 2 is a schematic diagram showing a configuration of a method for bonding dielectric layers according to an embodiment of the present invention, in which copper oxide is formed on the surface of a copper contact. [Diagram 5] FIG. 2 is a schematic diagram of a method for bonding dielectric layers according to an embodiment of the present invention, in which a copper contact containing copper oxide is immersed in a silver nitrate solution to replace it with silver ions. [Figure 6] 4 is a schematic diagram of an atomic arrangement after silver substitution in the bonding method of the dielectric layer according to the embodiment of the present invention. FIG. [Figure 7] FIG. 2 is a schematic diagram of a method for bonding dielectric layers according to an embodiment of the present invention, in which copper contacts are replaced with copper / silver oxide. [Figure 8] FIG. 2 is a schematic diagram illustrating the auto-decomposition of silver oxide in a high-temperature bonding process of two dielectric layers in air in a method for bonding dielectric layers according to an embodiment of the present invention. [Figure 9] FIG. 2 is a schematic diagram showing the configuration of two dielectric layers that are finally bonded in a method for bonding dielectric layers according to an embodiment of the present invention. [Figure 10]The image was taken using a Field Emission Scanning Electron Microscope (FE-SEM) (magnification 15,000x) after the copper was pickled in a 3.6 wt% hydrochloric acid (HCl) solution for 3 minutes. [Figure 11] FIG. 11 is an enlarged view of FIG. [Figure 12] The image was taken using a FE-SEM (magnification 10,000x) after copper was pickled in a 3.6 wt% hydrochloric acid solution for 3 minutes and then immersed in a 1 mM silver nitrate (AgNO3) solution for 10 seconds to cause a substitution reaction. [Figure 13] FIG. 13 is an enlarged view of FIG. [Figure 14] Copper was pickled in a 3.6 wt% hydrochloric acid solution for 3 minutes, then immersed in a 1 mM silver nitrate solution for 10 seconds to cause a substitution reaction, after which the entire surface signal was detected by energy dispersive X-ray microanalysis (EDX). [Figure 15] The copper element signal was detected by EDX after copper was pickled with a 3.6 wt% hydrochloric acid solution for 3 minutes and then immersed in a 1 mM silver nitrate solution for 10 seconds to cause a substitution reaction. [Figure 16] The silver element signal was detected by EDX after copper was pickled with a 3.6 wt % hydrochloric acid solution for 3 minutes and then immersed in a 1 mM silver nitrate solution for 10 seconds to cause a substitution reaction. [Figure 17] The image was taken using a FE-SEM (magnification 10,000x) after copper was pickled with a 3.6 wt% hydrochloric acid solution for 3 minutes and then immersed in a 1 mM silver nitrate solution for 30 seconds to cause a substitution reaction. [Figure 18] FIG. 17 is an enlarged view of FIG. [Figure 19] The copper was pickled with a 3.6 wt % hydrochloric acid solution for 3 minutes, and then immersed in a 1 mM silver nitrate solution for 30 seconds to cause a substitution reaction. The result is the signal over the entire surface detected by EDX. [Figure 20] The copper element signal was detected by EDX after copper was pickled with a 3.6 wt % hydrochloric acid solution for 3 minutes and then immersed in a 1 mM silver nitrate solution for 30 seconds to cause a substitution reaction. [Figure 21]The silver element signal was detected by EDX after copper was pickled with a 3.6 wt % hydrochloric acid solution for 3 minutes and then immersed in a 1 mM silver nitrate solution for 30 seconds to cause a substitution reaction. [Figure 22] The image was taken using FE-SEM (magnification 10,000x) after copper was pickled with a 3.6 wt% hydrochloric acid solution for 3 minutes and then immersed in a 1 mM silver nitrate solution for 60 seconds to cause a substitution reaction. [Diagram 23] FIG. 23 is an enlarged view of FIG. [Figure 24] The copper was pickled with a 3.6 wt % hydrochloric acid solution for 3 minutes, and then immersed in a 1 mM silver nitrate solution for 60 seconds to cause a substitution reaction. The result is the signal over the entire surface detected by EDX. [Diagram 25] The copper element signal was detected by EDX after copper was pickled with a 3.6 wt % hydrochloric acid solution for 3 minutes and then immersed in a 1 mM silver nitrate solution for 60 seconds to cause a substitution reaction. [Figure 26] The silver element signal was detected by EDX after copper was pickled in a 3.6 wt % hydrochloric acid solution for 3 minutes and then immersed in a 1 mM silver nitrate solution for 60 seconds to cause a substitution reaction. [Figure 27] The copper was pickled with a 3.6 wt % hydrochloric acid solution for 3 minutes, then immersed in a 1 mM silver nitrate solution for 120 seconds to cause a substitution reaction, and then the image was measured using a FE-SEM (magnification 10,000 times). [Figure 28] FIG. 27 is an enlarged view of FIG. [Figure 29] The copper was pickled with a 3.6 wt % hydrochloric acid solution for 3 minutes, and then immersed in a 1 mM silver nitrate solution for 120 seconds to cause a substitution reaction. The result is the overall surface signal detected by EDX. [Diagram 30] The copper element signal was detected by EDX after copper was pickled with a 3.6 wt % hydrochloric acid solution for 3 minutes and then immersed in a 1 mM silver nitrate solution for 120 seconds to cause a substitution reaction. [Diagram 31] The silver element signal was detected by EDX after copper was pickled with a 3.6 wt % hydrochloric acid solution for 3 minutes and then immersed in a 1 mM silver nitrate solution for 120 seconds to cause a substitution reaction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] In order to better explain the present invention, many specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be practiced without certain specific details.

[0017] As shown in FIG. 1, a method for joining copper members according to one embodiment of the present invention includes the following steps S11 to S13.

[0018] In step S11, the first copper member is oxidized to form a first copper oxide structure containing copper oxide and / or cuprous oxide on the surface of the first copper member, and the second copper member is oxidized to form a second copper oxide structure containing copper oxide and / or cuprous oxide on the surface of the second copper member.

[0019] In step S12, the first copper member including the first copper oxide structure and the second copper member including the second copper oxide structure are immersed in a reaction solution containing precious metal ions to cause a galvanic reaction, thereby replacing the first copper oxide structure with a first precious metal oxide structure and replacing the second copper oxide structure with a second precious metal oxide structure. In detail, the precious metal ions may be selected from the group consisting of silver, gold, ruthenium, rhodium, palladium, platinum, and iridium.

[0020] In step S13, the first precious metal oxide structure and the second precious metal oxide structure are joined at 25°C to 500°C (e.g., 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C) to connect the first copper member and the second copper member.

[0021] Optionally, step S10 may be included before step S11. Step S10 is a step of subjecting the first copper member and the second copper member to a chemical mechanical polishing (CMP) process, and when the first copper member and the second copper member that have been subjected to the chemical mechanical polishing (CMP) process come into contact with the air, they naturally begin to oxidize and generate copper oxide.

[0022] As shown in FIG. 2, a method for bonding dielectric layers according to another embodiment of the present invention includes the following steps S21 to S23.

[0023] In step S21, a first copper layer on the surface of a first dielectric layer is oxidized to form a first copper oxide structure on the surface of the first copper layer, and a second copper layer on the surface of a second dielectric layer is oxidized to form a second copper oxide structure on the surface of the second copper layer. In detail, the first copper layer can be formed on the surface of the first dielectric layer by vapor deposition, and the second copper layer can be formed on the surface of the second dielectric layer by vapor deposition, which may be physical vapor deposition or chemical vapor deposition.

[0024] In step S22, the first copper layer including the first copper oxide structure and the second copper layer including the second copper oxide structure are immersed in a reaction solution containing precious metal ions to cause a galvanic reaction, thereby replacing the first copper oxide structure with a first precious metal oxide structure and replacing the second copper oxide structure with a second precious metal oxide structure. In detail, the precious metal ions may be selected from the group consisting of silver, gold, ruthenium, rhodium, palladium, platinum and iridium.

[0025] In step S23, the first noble metal oxide structure and the second noble metal oxide structure are bonded to connect the first dielectric layer and the second dielectric layer at 25°C to 500°C (e.g., 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C).

[0026] Optionally, step S20 may be included before step S21. Step S20 is a step of subjecting the first copper layer and the second copper layer to a chemical mechanical polishing (CMP) process, and when the first copper layer and the second copper layer that have been subjected to the chemical mechanical polishing (CMP) process are exposed to air, they naturally begin to oxidize and generate copper oxide.

[0027] It is anticipated that during the life of the patent of this application, many related technologies relating to methods of joining copper members and methods of joining dielectric layers will be developed, and the scope of this application is intended to include all such new technologies a priori.

[0028] Throughout this application, various embodiments of the invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Thus, any description of a range should be considered to have specifically disclosed all possible subranges and individual numerical values ​​within that range. For example, a description of a range such as 1-6 should be considered to have specifically disclosed subranges such as 1-3, 1-4, 1-5, 2-4, 2-6, 3-6, etc., and individual numerical values ​​within said range such as 1, 2, 3, 4, 5, 6, etc. Any broad range is applicable.

[0029] As used herein, the terms "process" and "method" refer to methods, means, techniques, and procedures for accomplishing a particular task, including, but not limited to, methods, means, techniques, and procedures that are known to a practitioner in the chemical, materials, mechanical, computational, and digital arts or that are readily evolved from known methods, means, techniques, and procedures.

[0030] Reference is now made to the following examples, which together with the above descriptions, illustrate some embodiments of the invention in a non-limiting manner.

[0031] (Example) As shown in Fig. 3, first, a copper contact 2 (i.e., the first copper layer or the second copper layer of the present invention) is deposited on a dielectric layer 1 (i.e., the first dielectric layer or the second dielectric layer of the present invention), and the surface is mechanically and chemically polished and polished. As shown in Fig. 4, when the copper contact 2 is exposed to the air after polishing, a copper oxide 3 such as copper oxide / cuprous oxide (CuO / Cu2O) is generated on the surface.

[0032] Next, the copper contact 2 is immersed in an AgNO3 solution to cause a galvanic reaction and perform metal replacement on the surface. As shown in Figures 5 and 6, the copper ions in the cuprous oxide are spontaneously replaced by silver ions, and as shown in Figure 7, silver oxide (Ag2O)4 replaces the original copper oxide to form a copper / silver oxide structure.

[0033] Finally, at 150°C, two dielectric layers each containing a copper / silver oxide structure are connected so that the copper / silver oxide structure is symmetrical, and the connection method is to join the two dielectric layers by joining copper / silver oxide to silver oxide / copper. By utilizing the property that noble metal oxides automatically decompose at high temperatures in the atmosphere, for example, Ag2O and Au3O4 decompose at 150°C and room temperature, respectively, and as shown by the arrows in Figure 8, Ag2O decomposes to release oxygen and silver, and the oxide on its surface is spontaneously removed. In addition, by lowering the bonding temperature based on the decomposition temperature and diffusion kinetics of the oxide, the problem of thermal deposition in the final product is improved, the surface oxide is reduced, and the diffusion of copper atoms is further improved, resulting in a bonding interface with better strength and quality, such as the copper / silver / copper structure shown in Figure 9.

[0034] Replacement result FIG. 10 is an image obtained using a Field Emission Scanning Electron Microscope (FE-SEM) (magnification 15,000 times) after pickling copper with a 3.6 wt% hydrochloric acid (HCl) solution for 3 minutes. As shown in FIG. 10, a pure copper surface with no oxides is obtained. FIG. 11 is an enlarged view of FIG. 10.

[0035] Figure 12 shows an image taken using FE-SEM (magnification 10,000x) after copper was pickled with 3.6 wt% hydrochloric acid solution for 3 minutes and immersed in 1 mM silver nitrate (AgNO3) solution for 10 seconds for substitution reaction. As shown in Figure 12, after the substitution reaction, silver atoms are attached to the copper surface. Figure 13 is an enlarged view of Figure 12.

[0036] FIG. 14 shows the whole surface signal detected by energy dispersive X-ray microanalysis (EDX) after pickling copper with 3.6 wt% hydrochloric acid solution for 3 minutes, immersing in 1 mM silver nitrate solution for 10 seconds for substitution reaction. As shown in FIG. 14, in the mapping analysis by EDAX, the silver atomic particles are small, so the whole surface signal obtained is a copper signal. FIG. 15 shows the copper element signal detected by EDX after pickling copper with 3.6 wt% hydrochloric acid solution for 3 minutes, immersing in 1 mM silver nitrate solution for 10 seconds for substitution reaction. As shown in FIG. 15, there is a uniform layer of copper below the silver atoms. FIG. 16 shows the silver element signal detected by EDX after pickling copper with 3.6 wt% hydrochloric acid solution for 3 minutes, immersing in 1 mM silver nitrate solution for 10 seconds for substitution reaction. As shown in FIG. 16, the silver atoms are uniformly distributed on the copper surface.

[0037] Figure 17 shows an image obtained using FE-SEM after copper was pickled with 3.6 wt% hydrochloric acid solution for 3 minutes and then immersed in 1 mM silver nitrate solution for 30 seconds for substitution reaction. As shown in Figure 17, as the substitution time increases, the silver atoms are substituted on the copper surface more densely. Figure 18 is an enlarged view of Figure 17.

[0038] FIG. 19 shows the whole surface signal detected by EDX after pickling copper with 3.6wt% hydrochloric acid solution for 3 minutes and immersing in 1mM silver nitrate solution for 30 seconds. As shown in FIG. 19, in the mapping analysis by EDAX, the silver atomic particles are small, so the whole surface signal obtained is a copper signal. FIG. 20 shows the copper element signal detected by EDX after pickling copper with 3.6wt% hydrochloric acid solution for 3 minutes and immersing in 1mM silver nitrate solution for 30 seconds. As shown in FIG. 20, there is a uniform layer of copper below the silver atoms. FIG. 21 shows the silver element signal detected by EDX after pickling copper with 3.6wt% hydrochloric acid solution for 3 minutes and immersing in 1mM silver nitrate solution for 30 seconds. As shown in FIG. 21, the silver atomic signal is more dense overall than when immersed in 10 seconds, which indicates that the silver atoms are more densely located on the copper surface.

[0039] Figure 22 shows an image measured by FE-SEM after copper was pickled with 3.6 wt% hydrochloric acid solution for 3 minutes and immersed in 1 mM silver nitrate solution for 60 seconds for substitution reaction. As shown in Figure 22, as the substitution time increases, the silver atoms are substituted on the copper surface more densely. Figure 23 is an enlarged view of Figure 22.

[0040] FIG. 24 shows the whole surface signal detected by EDX after pickling copper with 3.6wt% hydrochloric acid solution for 3 minutes and immersing in 1mM silver nitrate solution for 60 seconds. As shown in FIG. 24, in the mapping analysis by EDAX, the silver atomic particles are small, so the whole surface signal obtained is a copper signal. FIG. 25 shows the copper element signal detected by EDX after pickling copper with 3.6wt% hydrochloric acid solution for 3 minutes and immersing in 1mM silver nitrate solution for 60 seconds. As shown in FIG. 25, there is a uniform layer of copper below the silver atoms. FIG. 26 shows the silver element signal detected by EDX after pickling copper with 3.6wt% hydrochloric acid solution for 3 minutes and immersing in 1mM silver nitrate solution for 60 seconds. As shown in FIG. 26, the silver atomic signal is more dense overall than when immersed in 30 seconds, which indicates that the silver atoms are more densely located on the copper surface.

[0041] Figure 27 shows images measured using FE-SEM after copper was pickled with 3.6 wt% hydrochloric acid solution for 3 minutes and immersed in 1 mM silver nitrate solution for substitution reaction for 120 seconds. As shown in Figure 27, as the substitution time increases, silver atoms are substituted more densely on the copper surface, which is most noticeable at 120 seconds. Figure 28 is an enlarged view of Figure 27.

[0042] Figure 29 shows the whole surface signal detected by EDX after copper was pickled with 3.6wt% hydrochloric acid solution for 3 minutes, immersed in 1mM silver nitrate solution for 120 seconds replacement reaction. As shown in Figure 29, in the mapping analysis by EDAX, the silver atomic particles are small, so the whole surface signal obtained is a copper signal, but as the time increases, some silver particles with larger sizes appear in the figure. Figure 30 shows the copper element signal detected by EDX after copper was pickled with 3.6wt% hydrochloric acid solution for 3 minutes, immersed in 1mM silver nitrate solution for 120 seconds replacement reaction. As shown in Figure 30, there is a uniform layer of copper below the silver atoms. FIG. 31 shows the silver element signal detected by EDX after copper was pickled with a 3.6 wt % hydrochloric acid solution for 3 minutes and then immersed in a 1 mM silver nitrate solution for a substitution reaction for 120 seconds. As shown in FIG. 31, compared to the case of substitution for 60 seconds, the silver atomic signal is stronger overall, and the silver atoms are more uniformly distributed on the copper surface.

[0043] The present invention has been disclosed by preferred embodiments, but they are not intended to limit the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention should be defined by the appended claims. [Explanation of symbols]

[0044] 1 Dielectric layer 2 Copper contacts 3 Copper oxide 4. Silver Oxide S10 to S13 Steps of the method for joining copper members according to the present invention S20 to S23: Steps of the method for bonding dielectric layers of the present invention

Claims

1. A step S11 of oxidizing a first copper member to form a first copper oxide structure on a surface of the first copper member and oxidizing a second copper member to form a second copper oxide structure on a surface of the second copper member; Step S12 of immersing the first copper member including the first copper oxide structure and the second copper member including the second copper oxide structure in a reaction solution containing precious metal ions to cause a galvanic reaction, thereby replacing the first copper oxide structure with a first precious metal oxide structure and replacing the second copper oxide structure with a second precious metal oxide structure; and step S13 of directly contacting and bonding the first and second noble metal oxide structures to connect the first and second copper members at 25° C. to 500° C.; A method for joining copper components.

2. The method further includes a step S10 of performing a chemical mechanical polishing (CMP) process on the first copper member and the second copper member before the step S11. The method for joining copper members according to claim 1.

3. The precious metal ions are selected from the group consisting of silver, gold, ruthenium, rhodium, palladium, platinum and iridium; The method for joining copper members according to claim 1.

4. Step S21: oxidizing a first copper layer on a surface of a first dielectric layer to form a first copper oxide structure on the surface of the first copper layer, and oxidizing a second copper layer on a surface of a second dielectric layer to form a second copper oxide structure on the surface of the second copper layer; a step S22 of immersing the first copper layer including the first copper oxide structure and the second copper layer including the second copper oxide structure in a reaction solution containing a noble metal ion to cause a galvanic reaction, thereby replacing the first copper oxide structure with a first noble metal oxide structure and replacing the second copper oxide structure with a second noble metal oxide structure; and step S23 of directly contacting and bonding the first and second noble metal oxide structures at 25° C. to 500° C. to connect the first and second dielectric layers. A method for bonding dielectric layers.

5. The method further includes a step S20 of performing a chemical mechanical polishing (CMP) process on the first copper layer and the second copper layer before the step S21. The method for bonding dielectric layers according to claim 4 .

6. The precious metal ions are selected from the group consisting of silver, gold, ruthenium, rhodium, palladium, platinum and iridium; The method for bonding dielectric layers according to claim 4 .

7. the first copper layer is formed on the surface of the first dielectric layer by vapor deposition, and the second copper layer is formed on the surface of the second dielectric layer by vapor deposition; The method for bonding dielectric layers according to claim 4 .

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