Metal-filled trench structure and method of making the same

Abstract

The application provides a metal-filled trench structure and a preparation method thereof. By arranging an insulating film layer between a first metal layer and a second metal layer, in a CMP process of the metal-filled trench using an eddy current sensor, the second metal layer is first ground. Due to the insulating effect of the insulating film layer, the eddy current noise generated by the first metal layer in the trench can be shielded, and the Endpoint terminal point capture accuracy of the second metal layer grinding is improved. At the same time, especially when the first metal layer on the wafer surface is ground, due to the insulating effect of the insulating film layer, and the lowest point of the insulating film layer in the trench area is located at the position of 500 nm to 500 nm of the top of the trench, the influence of the eddy current noise generated by the first metal layer in the trench on the eddy current when the first metal layer on the wafer surface is ground can be effectively shielded, and the Endpoint terminal point capture accuracy is improved. Furthermore, the eddy current signal can be improved as a whole, and the CLC and RTPC functions of automatically adjusting the uniformity of the wafer surface are enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a metal-filled trench structure and a preparation method thereof. Background Art

[0002] The integrated circuit (IC) industry is growing rapidly, with continuous advancements in materials and design technologies resulting in increasingly smaller and more complex circuits in each new generation of products. Throughout the evolution of ICs, functional density (the number of connected components per chip area) has generally increased, while geometry size (the smallest component or circuit size that can be produced by the process) has gradually decreased. This reduction in size improves production efficiency and reduces costs, but it also increases the complexity of IC manufacturing. The semiconductor device manufacturing process involves numerous steps, with hundreds of steps typically required on a single wafer to complete an integrated circuit. These steps include depositing dielectric and conductive materials on the wafer, forming circuit patterns through photolithography, etching, and development, and often also polishing to flatten the surface. Common polishing operations, such as chemical mechanical planarization (CMP), are a crucial step in the planarization process. In current semiconductor manufacturing processes, CMP processes are used in many cases, such as silicon oxide polishing in shallow trench isolation (STI), silicon oxide polishing in local interconnect (LI), silicon oxide polishing in interlayer dielectric (ILD), and metal interconnect line polishing in metal interconnect processes.

[0003] The polishing apparatus used in the CMP process typically includes a polishing table that supports a polishing pad and a wafer holding mechanism, such as a top ring or polishing head, that holds the wafer. The polishing apparatus supplies polishing liquid from a polishing liquid supply nozzle to the polishing pad, pressing the wafer against the polishing pad's surface (the polishing surface) at a specified pressure. The polishing table and wafer holding mechanism rotate, causing the wafer to slide against the polishing surface, polishing the wafer's surface to a flat, mirror-like finish.

[0004] Taking the copper metal chemical mechanical polishing process as an example, in the preparation process of copper metal connection through-holes, a deep well type deep groove is generally formed in the oxide layer, and then metal copper is filled in the deep well type deep groove. During the filling process, metal copper is also deposited on the surface of the oxide layer; at this time, the metal copper located on the surface of the oxide layer needs to be removed through the metal copper chemical mechanical polishing process, and only the metal copper in the deep well type deep groove is retained as a metal connection. In the existing metal chemical polishing process, the eddy current sensor (Eddy Current Monitor of Resistance, RECM) is generally used to detect the eddy current capture end point (Endpoint) and adjust the uniformity (uniformity) of the wafer surface. However, the existing RECM detection has a large fluctuation of the Endpoint curve in the CMP process of trench metal filling, such as Figure 1 As shown in the figure, the accuracy of endpoint detection, closed loop control (CLC) or real-time process control (RTPC) during the polishing process may be affected, resulting in metal residue on the wafer surface and reducing the polishing uniformity of the wafer surface. This phenomenon is particularly evident in the CMP process of deep and wide trenches. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a metal-filled groove structure and a preparation method thereof, which is used to solve the problem in the prior art that the Endpoint curve fluctuates greatly during the CMP process of the metal-filled groove using an eddy current sensor, affecting the accuracy of Endpoint detection during the grinding process, closed-loop control (CLC) or real-time process control (RTPC), resulting in metal residue on the wafer surface and reducing the uniformity of wafer surface grinding.

[0006] To achieve the above-mentioned and other related objectives, the present invention provides a method for preparing a metal-filled trench structure, the method comprising:

[0007] Providing a wafer, wherein a groove is formed on the wafer;

[0008] A stacked film structure is formed on the wafer and in the trench, and a portion of the film layer of the stacked film structure fully fills the trench; wherein the stacked film structure sequentially includes: a first metal layer, which fills the trench and the wafer, and is concave in the trench area and the adjacent wafer area; an insulating film layer, which is deposited on the surface of the first metal layer, and the lowest point of the insulating film layer in the trench area is located at a position between -500nm and 500nm from the top of the trench; a second metal layer of the same nature as the first metal layer, which is deposited on the insulating film layer, and the first metal layer, the insulating film layer, and the second metal layer are conformally nested in sequence;

[0009] causing an eddy current sensor disposed inside the grinding table to rotate together with the grinding table;

[0010] The wafer formed with the stacked film structure is pressed against the grinding pad on the rotating grinding table by a grinding head to grind the stacked film structure on the surface of the wafer, wherein the grinding process includes three steps: the first step is to grind the second metal layer, and perform a first grinding endpoint detection on the end of grinding the second metal layer by the eddy current sensor; the second step is to grind the insulating film layer and the first metal layer, and perform a second grinding endpoint detection on the end of grinding the first metal layer by the eddy current sensor; the third step is to grind the wafer and the groove for a preset time so that the groove depth reaches a preset requirement.

[0011] Optionally, the groove has a depth of 150 nm to 5000 nm and a width of 150 nm to 5000 nm, both inclusive.

[0012] Optionally, the stacked film structure also includes: a first adhesion layer and a second adhesion layer; wherein, the first adhesion layer is deposited on the groove surface and the wafer surface of the wafer and is located below the first metal layer, and the second adhesion layer is deposited on the surface of the insulating film layer and is located below the second metal layer.

[0013] Furthermore, the first metal layer and the second metal layer are formed by an electroplating process, the insulating film layer is formed by a chemical vapor deposition process, and the first adhesion layer and the second adhesion layer are formed by a physical vapor deposition process.

[0014] Furthermore, the material of the first adhesion layer and the second adhesion layer is at least one of tantalum and tantalum nitride, or at least one of titanium and titanium nitride.

[0015] Furthermore, in the first step of the grinding process, the second adhesion layer serves as a grinding endpoint for finishing grinding the second metal layer, and in the second step of the grinding process, the first adhesion layer serves as a grinding endpoint for finishing grinding the first metal layer.

[0016] Optionally, the materials of the first metal layer and the second metal layer are metal materials used for semiconductor wiring.

[0017] Furthermore, the first metal layer and the second metal layer are made of copper, cobalt, tungsten or aluminum.

[0018] Furthermore, the material of the insulating film layer is at least one of SiCN, SiCO, SiN and SiO2, and the thickness of the insulating film layer is 5nm to 500nm, including end points.

[0019] The present invention also provides a metal-filled trench structure, which is prepared using any one of the above methods for preparing a metal-filled trench structure.

[0020] As described above, the metal-filled groove structure and preparation method of the present invention, by setting an insulating film layer between the first metal layer and the second metal layer, when the metal-filled groove is subjected to the CMP process using an eddy current sensor, the second metal layer is first polished. Due to the insulating effect of the insulating film layer, the turbine current noise generated by the first metal layer in the groove can be shielded, the turbine current noise during the polishing of the second metal layer can be reduced, and the accuracy of the Endpoint capture of the polishing of the second metal layer can be improved; at the same time, especially when the first metal layer on the wafer surface is polished, due to the insulating effect of the insulating film layer, and the lowest point of the insulating film layer in the groove area is located at a position of -500nm to 500nm from the top of the groove, the influence of the turbine current noise generated by the first metal layer in the groove on the turbine current during the polishing of the first metal layer on the wafer surface can be effectively shielded, the fluctuation of the Endpoint curve can be effectively reduced, and the accuracy of the Endpoint capture can be improved; furthermore, by reducing the turbine current noise generated by the first metal layer in the groove, the overall turbine current signal can be improved, the CLC and RTPC functions of automatically adjusting the uniformity of the wafer surface can be enhanced, and the uniformity of the wafer surface polishing can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The figure shows a schematic diagram of an endpoint detection curve during a CMP process of a metal-filled trench using an existing eddy current sensor.

[0022] Figure 2 It is a schematic cross-sectional view of the stacked film structure for filling the trench according to the present invention.

[0023] Figure 3 A diagram showing the positional relationship between the insulating film layer and the trench top in the trench-filling stacked film structure of the present invention is shown.

[0024] Figures 4 to 7The schematic diagram shows the cross-sectional structure of the polishing process in the CMP process method of the stacked film structure filling the trench of the present invention.

[0025] Figure 8 It is a schematic diagram of an endpoint detection curve during a CMP process of a metal-filled trench using the trench-filling stacked film structure of the present invention.

[0026] Component number description

[0027] 10 wafers

[0028] 11 Grooves

[0029] 12 First Adhesion Layer

[0030] 13. First metal layer

[0031] 14 Insulation film layer

[0032] 15 Second adhesive layer

[0033] 16 Second metal layer DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0035] See also Figures 2 to 8 It should be noted that the diagrams provided in this embodiment are merely schematic illustrations of the basic concept of the present invention. Therefore, the diagrams only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0036] As described in the background technology, the existing RECM detection has a large fluctuation in the Endpoint curve during the CMP process of metal filling in the trench. The inventors have found through research that the reason for this problem may be that: during the CMP process of metal-filled trenches, the metal filled in the trench will also generate a turbine current, and the wider and / or deeper the trench is, the more metal is filled, and the greater the turbine current generated. This signal will affect the RECM signal, increase the noise of the turbine current signal, cause the Endpoint curve to fluctuate, and reduce the accuracy of the Endpoint end point capture. Moreover, when the trench is larger and / or deeper, the turbine current generated by the metal filled in the trench is also greater, resulting in greater noise in the turbine current signal. Therefore, this phenomenon is more obvious in the CMP process of deep and wide trenches.

[0037] Based on the above knowledge, Figure 2 and Figure 7 As shown, this embodiment provides a method for preparing a metal-filled trench structure, the preparation method comprising:

[0038] S1, such as Figure 2 As shown, a wafer 10 is provided, and a groove 11 is formed on the wafer 10 .

[0039] S2. A stacked film structure is formed on the wafer 10 and in the groove 11, and a part of the film layer of the stacked film structure fills the groove 11; wherein the stacked film structure comprises in sequence: a first metal layer 13, which is filled in the groove 11 and on the wafer 10, and is in a concave shape in the groove area and the adjacent wafer area. It should be noted that the concave shape of the first metal layer 13 in the groove area and the adjacent wafer area is a natural form formed based on all existing slot filling processes. The depth of the concave shape and the size of the concave shape are determined by the specific slot filling process and the corresponding process parameters, etc., and are not overly restricted here; an insulating film layer 14, which is deposited on the surface of the first metal layer 13. Figure 3 As shown, the insulating film layer 14 is located at the lowest point of the groove area at a position of -500nm to 500nm from the top of the groove; the second metal layer 16, which is homogeneous with the first metal layer 13, is deposited on the insulating film layer 14, and the first metal layer 13, the insulating film layer 14 and the second metal layer 16 are conformally nested in sequence, that is, the surface morphology of the insulating film layer 14 and the second metal layer 16 remains consistent with the surface morphology of the first metal layer 13, which is also a natural form formed based on all existing deposition (including electroplating) processes.

[0040] S3. The eddy current sensor disposed inside the grinding table is rotated together with the grinding table.

[0041] S4, such as Figures 4 to 7 As shown, the wafer is pressed by the polishing head on the polishing pad of the rotating polishing table to polish the stack film structure on the wafer surface, wherein the polishing process includes three steps: first, polishing the second metal layer 16 and performing first polishing endpoint detection by the eddy current sensor on the end of polishing of the second metal layer 16; second, polishing the insulating film layer 14 and the first metal layer 13 and performing second polishing endpoint detection by the eddy current sensor on the end of polishing of the first metal layer 13; third, polishing the wafer 10 and the trench 11 for a preset time to make the trench depth reach a preset requirement.

[0042] The preparation method of the metal-filled trench structure of the embodiment can shield the eddy current noise generated by the first metal layer 13 in the trench when polishing the second metal layer 16 due to the insulation effect of the insulating film layer 14, reduce the eddy current noise when polishing the second metal layer 16, and improve the Endpoint endpoint capture accuracy when polishing the second metal layer 16. At the same time, especially when polishing the first metal layer 13 on the wafer surface, the insulating film layer 14 is also insulated, and the lowest point of the insulating film layer 14 in the trench area is located at the position of -500nm~500nm on the top of the trench, which can effectively shield the influence of the eddy current noise generated by the first metal layer 13 in the trench on the eddy current when polishing the first metal layer 13 on the wafer surface, effectively reduce the fluctuation of the Endpoint curve, and improve the Endpoint endpoint capture accuracy, as shown in Figure 8 Furthermore, by reducing the eddy current noise generated by the first metal layer 13 in the trench, the eddy current signal can be improved as a whole, the CLC and RTPC functions of automatically adjusting the uniformity of the wafer surface can be enhanced, and the uniformity of polishing the wafer surface can be improved.

[0043] It is known that the number of trenches 11 on the wafer 10 can be set according to actual needs, and is generally more than one. In the embodiment, only one trench is shown for the convenience of understanding, but the number cannot be regarded as a limitation of the protection scope of the present application. In addition, the wafer 10 here refers to a wafer that needs to be subjected to a CMP process at any stage of a semiconductor process, wherein some other device structures can be formed, and the specific limitations are determined according to the process stage and different semiconductor structures, which are not limited herein.

[0044] As described above, the stacked film structure of this embodiment provides a more effective CMP process improvement for wider and deeper trenches. Based on the trench depth and width requirements of existing semiconductor processes, trench 11 is selected to have a depth of 150nm to 5000nm and a width of 150nm to 5000nm, both inclusive, which significantly improves the CMP process. However, based on the above principles, if the trench depth and width requirements are even greater in future processes, the stacked film structure of this embodiment may be more effectively used for CMP.

[0045] Generally, in order to improve the adhesion between metal and insulating materials, an adhesion layer is formed between the two. Figure 2 As shown, a first adhesion layer 12 is deposited on the surface of the trench 11 of the wafer 10 and on the surface of the wafer 10, and the first adhesion layer 12 is located below the first metal layer 13. A second adhesion layer 15 is deposited on the surface of the insulating layer 14, and the second adhesion layer 15 is located below the second metal layer 16. In addition, the first adhesion layer 12 and the second adhesion layer 15 are conformally nested with the first metal layer 13, the insulating film layer 14, and the second metal layer 16 in the laminated film structure. Preferably, the first metal layer 13 and the second metal layer 16 are formed by electroplating, the insulating film layer 14 is formed by chemical vapor deposition, and the first adhesion layer 12 and the second adhesion layer 15 are formed by physical vapor deposition.

[0046] The first metal layer 13 and the second metal layer 16 are made of metal materials suitable for trench filling. Currently, trench filling is primarily used to achieve electrical connection, i.e., to form semiconductor electrical connections. Based on this function, suitable materials for semiconductor electrical connections can be metal materials with good electrical conductivity and stable chemical properties, such as copper, cobalt, tungsten, or aluminum, with copper being the most common material.

[0047] The first adhesive layer 12 and the second adhesive layer 15 are mainly used for adhesion, so that the metal material formed thereon can be firmly adhered. The material is generally selected from at least one of tantalum or tantalum nitride, or at least one of titanium or titanium nitride. In some specific cases, the selection of the adhesive layer material also plays a diffusion barrier role according to the properties of the metal layer material. For example, when the material of the first metal layer 13 and the second metal layer 16 is selected as copper material, the material of the first adhesive layer 12 and the second adhesive layer 15 is selected as a mixed material layer of tantalum and tantalum nitride, which can better adhere the copper material and also plays a certain barrier role to prevent the diffusion of the easily diffused copper particles into the wafer material and the insulating film layer 14 where the trench is located. Based on this consideration, when the material of the first metal layer 13 and the second metal layer 16 is selected as tungsten material, the material of the first adhesive layer 12 and the second adhesive layer 15 is preferably selected as a mixed material layer of titanium and titanium nitride.

[0048] The material of the insulating film layer 14 is generally selected from an insulating material with good insulating properties, such as at least one of SiCN, SiCO, SiN, and SiO2, etc. When the material of the first metal layer 13 and the second metal layer 16 is selected as easily diffused copper material, the material of the insulating film layer 14 is preferably selected as SiCN, which can further block the diffusion of copper particles while playing an insulating role, thereby avoiding the influence of the vortex current noise generated in the trench of the first metal layer 13 on the Endpoint terminal capture accuracy during the CMP polishing of the second metal layer 16 due to the diffusion of copper particles.

[0049] As an example, the thickness of the insulating film layer 14 is generally selected as 5 nm to 500 nm, including the end point value.

[0050] As another example, the thickness of the first adhesive layer 12 and the second adhesive layer 15 is generally tens of nanometers.

[0051] The grinding device for the CMP process generally includes: a grinding table, a grinding pad, a grinding head, a drive device and a grinding liquid supply system; the grinding table supports the grinding pad, and a dresser is also provided on the grinding pad to dress the grinding pad, and the wafer is fixed on the grinding head; when in use, the drive device drives the grinding table to rotate, pressing the grinding head toward the grinding pad to grind the wafer surface, and during grinding, the grinding liquid supply system supplies grinding liquid or slurry to the grinding pad, and performs chemical grinding and / or physical and mechanical grinding on the wafer according to different requirements. At this time, the eddy current sensor is set inside the grinding table. When the grinding table rotates, the eddy current sensor also rotates with the grinding table. Since the grinding table drives the grinding pad to rotate and the wafer is also rotating during the grinding process, the eddy current sensor can detect the current on the entire wafer surface and obtain the endpoint detection signal accordingly.

[0052] Preferably, when the stacked film structure filling the trench further includes the first adhesion layer 12 and the second adhesion layer 15, in S4, the grinding process includes three steps specifically:

[0053] The first step, such as Figure 4 As shown, the second metal layer 16 is ground, and the first grinding endpoint detection is performed on the grinding end of the second metal layer 16 by the eddy current sensor. Here, the eddy current sensor detects the second adhesion layer 15 as the grinding endpoint through the change of current. Since CMP grinding is a process of flattening the wafer surface, when performing this step, after the second metal layer 16 on the wafer surface is ground, the second metal layer 16 in the inner recess above the groove will still be partially retained, as shown in FIG. Figure 4 As shown, in addition, the method generally used to grind the second metal layer 16 is mainly chemical grinding, that is, by supplying abrasive particles that can react with the second metal layer 16 to the grinding pad, making it react with the second metal layer 16, and washing away the reactants by grinding the material.

[0054] Second step, grinding the second adhesive layer 15, the insulating film layer 14 and the first metal layer 13, and detecting the second grinding end point by the eddy current sensor, here, the eddy current sensor detects the first adhesive layer 12 as the grinding end point by the change of current, it is to be explained that the second metal layer 16 left in the inner recess in the first step is also removed in this step, and the main means of grinding is chemical grinding, and the main means of grinding the second adhesive layer 15 and the insulating film layer 14 is physical and mechanical grinding, and the main means of grinding the first metal layer 13 is chemical grinding, the specific process is: adding particles that can react with the first metal layer 13 and the second metal layer 16 in the grinding liquid, and adding grinding particles that have physical and mechanical effects, the particles that have chemical effects can grind away the first metal layer 13 and the second metal layer 16 by chemical effects, and the grinding particles that have physical and mechanical effects can grind away the second adhesive layer 15 and the insulating film layer 14, so as to obtain a wafer with a flat surface, as shown in Figure 5 and Figure 6 , Figure 5 The structure in Figure 6 is the structure obtained after the lowest point of the insulating film layer 14 is formed in the groove after grinding outside the groove,

[0055] Third step, grinding the first adhesive layer 12, the wafer and the groove for a preset time to make the groove depth reach the preset requirement; in this step, the first adhesive layer 12 on the wafer surface needs to be removed first, and on this basis, the wafer surface and the groove surface are ground for a preset time to make the groove depth reach the preset requirement, here, the preset time of grinding and the preset requirement of the groove depth are set according to actual needs; in addition, the principle of grinding the first adhesive layer 12 and the wafer surface and the groove surface is that the metal material is mainly ground by chemical effects, and the insulating material is mainly ground by physical and mechanical effects, in this grinding process, the proportion parameters of different particles in the grinding liquid are adjusted to make the grinding rate of different areas of the wafer surface consistent, so as to obtain a flat surface, which belongs to the conventional adjustment means in the art, and is selected and set according to the specific situation, which is not limited here.

[0056] Based on the above preparation method of the metal-filled groove structure, the embodiment also provides a metal-filled groove structure prepared by the above preparation method.

[0057] In summary, the present invention provides a metal-filled groove structure and a preparation method thereof. By setting an insulating film layer between a first metal layer and a second metal layer, when the metal-filled groove is subjected to a CMP process using an eddy current sensor, the second metal layer is first ground. Due to the insulating effect of the insulating film layer, the turbine current noise generated by the first metal layer in the groove can be shielded, the turbine current noise during the grinding of the second metal layer can be reduced, and the accuracy of the Endpoint capture of the grinding of the second metal layer can be improved. At the same time, especially when the first metal layer on the wafer surface is ground, due to the insulating effect of the insulating film layer, and the lowest point of the insulating film layer in the groove area is located at a position of -500nm to 500nm from the top of the groove, the influence of the turbine current noise generated by the first metal layer in the groove on the turbine current during the grinding of the first metal layer on the wafer surface can be effectively shielded, the fluctuation of the Endpoint curve can be effectively reduced, and the accuracy of the Endpoint capture can be improved. Furthermore, by reducing the turbine current noise generated by the first metal layer in the groove, the turbine current signal can be improved as a whole, the CLC and RTPC functions of automatically adjusting the uniformity of the wafer surface can be enhanced, and the uniformity of the wafer surface grinding can be improved. Therefore, the present invention effectively overcomes various shortcomings of the prior art and has high industrial utilization value.

[0058] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for preparing a metal-filled trench structure, characterized in that: The preparation method comprises: Providing a wafer, wherein a groove is formed on the wafer; A stacked film structure is formed on the wafer and in the trench, and a portion of the film layer of the stacked film structure fully fills the trench; wherein the stacked film structure sequentially includes: a first metal layer, which fills the trench and the wafer, and is concave in the trench area and the adjacent wafer area; an insulating film layer, which is deposited on the surface of the first metal layer, and the lowest point of the insulating film layer in the trench area is located at a position between -500nm and 500nm from the top of the trench; a second metal layer of the same nature as the first metal layer, which is deposited on the insulating film layer, and the first metal layer, the insulating film layer, and the second metal layer are conformally nested in sequence; causing an eddy current sensor disposed inside the grinding table to rotate together with the grinding table; The wafer formed with the stacked film structure is pressed against the grinding pad on the rotating grinding table by a grinding head to grind the stacked film structure on the surface of the wafer, wherein the grinding process includes three steps: the first step is to grind the second metal layer, and perform a first grinding endpoint detection on the end of grinding the second metal layer by the eddy current sensor; the second step is to grind the insulating film layer and the first metal layer, and perform a second grinding endpoint detection on the end of grinding the first metal layer by the eddy current sensor; the third step is to grind the wafer and the groove for a preset time so that the groove depth reaches a preset requirement.

2. The method for preparing a metal-filled trench structure according to claim 1, wherein: The groove has a depth of 150 nm to 5000 nm and a width of 150 nm to 5000 nm, both inclusive.

3. The method for preparing a metal-filled trench structure according to claim 1, wherein: The stacked film structure also includes: a first adhesion layer and a second adhesion layer; wherein, the first adhesion layer is deposited on the groove surface and the wafer surface of the wafer and is located below the first metal layer, and the second adhesion layer is deposited on the surface of the insulating film layer and is located below the second metal layer.

4. The method for preparing a metal-filled trench structure according to claim 3, wherein: The first metal layer and the second metal layer are formed by an electroplating process, the insulating film layer is formed by a chemical vapor deposition process, and the first adhesion layer and the second adhesion layer are formed by a physical vapor deposition process.

5. The method for preparing a metal-filled trench structure according to claim 3, wherein: The material of the first adhesion layer and the second adhesion layer is at least one of tantalum and tantalum nitride, or at least one of titanium and titanium nitride.

6. The method for preparing a metal-filled trench structure according to claim 3, wherein: In the first step of the grinding process, the second adhesion layer serves as a grinding end point for grinding the second metal layer. In the second step of the grinding process, the first adhesion layer serves as a grinding end point for grinding the first metal layer.

7. The method for preparing a metal-filled trench structure according to claim 1, wherein: The materials of the first metal layer and the second metal layer are metal materials used for semiconductor wiring.

8. The method for preparing a metal-filled trench structure according to claim 7, wherein: The first metal layer and the second metal layer are made of copper, cobalt, tungsten or aluminum.

9. The method for preparing a metal-filled trench structure according to any one of claims 1 to 8, wherein: The material of the insulating film layer is at least one of SiCN, SiCO, SiN and SiO2, and the thickness of the insulating film layer is 5nm to 500nm, including end points.

10. A metal-filled trench structure, characterized in that: The metal-filled trench structure is prepared by the method for preparing the metal-filled trench structure according to any one of claims 1 to 9.

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