A measuring system and method for evaluating in-situ mass transfer capability of wafer-level electroplating process

Abstract

The application belongs to the technical field of electroplating, and particularly discloses a measuring system and method for in-situ evaluation of mass transfer capacity of wafer-level electroplating process, wherein the measuring system is a three-electrode measuring system, and comprises a wafer electrode, a reference electrode and an anode in an electroplating device; a plurality of microelectrodes and a surface electrode are arranged on the wafer electrode; the microelectrodes are embedded in the surface electrode; an air gap exists between the microelectrodes and the surface electrode; the microelectrodes and the surface electrode are electrically isolated and can be independently powered, respectively. The application can realize in-situ measurement and characterization of the mass transfer capacity of the wafer-level electroplating process independently; the application can realize in-situ measurement and characterization of the mass transfer capacity of wafer surface electroplating process, copper damascene interconnection electroplating process, TSV / TGV hole copper electroplating process and the like; and the application supports design and development of electroplating equipment mass transfer system, electroplating additives and formula and the like.

Description

Technical Field

[0001] This invention relates to the field of electroplating technology, and more specifically to a measurement system and method for in-situ evaluation of mass transfer capability in wafer-level electroplating processes. Background Technology

[0002] In the field of integrated circuit manufacturing, electroplating is a crucial manufacturing process for achieving micro- and nano-scale electrical interconnects. Its applications cover integrated circuit chips, packaging substrates, packages, and printed circuit boards, such as the Damascus copper interconnects in CMOS integrated circuit chips, TSV interconnects in Chipplets 3D integrated packaging, RDLs, and copper bumps. During wafer-level electroplating, the high aspect ratio structure and edge effects of micropores / grooves on the cathode surface place stringent requirements on the mass transfer capability of the electroplating solution to the cathode / wafer surface. To optimize the mass transfer capability in wafer-level electroplating, various types of stirring methods, flow field designs, and electric field designs have been proposed at the equipment design level. At the electroplating solution development level, different additive designs, such as inhibitors and leveling agents, have been proposed. In 2001, Semitool Corporation in the United States designed a triangular stirring blade and added three rows of arrayed micropores to supply the plating solution, forming a microjet. In 2017, EEJA in Japan utilized planetary gears to achieve the rotation and oscillation motion of the blade. In 2020, Shengmei Semiconductor added a central spray nozzle and radial oblique spray ribs below the diffuser plate to reconstruct the jet flow field. In 2000, Linde Group disclosed an acidic copper plating solution containing a low-molecular-weight leveling agent in patent application EP1069211A2. In 2016, Shanghai Xinyang Semiconductor disclosed an additive mainly composed of polyethylene glycol and polyvinyl alcohol in patent application CN103361681, which can reduce the possibility of voids in the plating layer.

[0003] Currently, industry analysis of mass transfer capabilities in wafer-level electroplating processes primarily focuses on the final quality of the electroplating process. At the equipment level, the design of the electroplating solution mass transfer system and the electroplating solution chemical system are strongly coupled, making it impossible to independently evaluate the effectiveness of either the mass transfer system or the electroplating solution in wafer-level electroplating equipment. Industry players often collaborate on R&D and form partnerships through commercial cooperation, while new entrants typically enter the market through imitation, assimilation, and substitution. Decoupling the effects of the equipment, electroplating solution mass transfer system, and electroplating chemicals in the electroplating process, and enabling independent evaluation and analysis of their respective roles, is crucial for both equipment design and development, as well as the design and development of electroplating additives and chemicals. Calculating the diffusion layer thickness by measuring the current under diffusion-limited conditions is currently the academic method for evaluating the mass transfer capabilities of electroplating equipment. However, academic research typically involves testing in small electrolytic cells, where the flow field, electric field, and electrochemical concentration field of the electroplating solution differ significantly from those in wafer-level electroplating equipment.

[0004] To address the challenge of in-situ measurement and evaluation of mass transfer capacity in wafer-level electroplating processes, it is essential to develop a new measurement system and method. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of the existing technology and provide a measurement system and method for in-situ evaluation of the mass transfer capability of a wafer-level electroplating process. By assembling a three-electrode measurement system and obtaining the limiting current under diffusion-limited conditions at different locations on the wafer using linear sweep voltammetry (LSV) and potentiostatic methods, the thickness of the diffusion layer is calculated based on the parameters of the electroplating solution, thereby evaluating the mass transfer capability of the wafer-level electroplating process mass transfer system.

[0006] To achieve the above objectives, one of the technical solutions of the present invention is: a measurement system for in-situ evaluation of mass transfer capability in a wafer-level electroplating process. The measurement system is a three-electrode measurement system, including a wafer electrode, a reference electrode, and an anode in the electroplating device. The wafer electrode is placed in an electroplating tank. Multiple microelectrodes and one surface electrode are provided on the wafer electrode. The microelectrodes are embedded in the surface electrode. There is an air gap between the microelectrodes and the surface electrode. The two are electrically isolated and can be powered independently.

[0007] The disc electrode is placed in the electroplating tank as the cathode / working electrode, while the reference electrode needs to be in contact with the electroplating solution.

[0008] In a preferred embodiment of the present invention, the size, number, and arrangement of the microelectrodes can be set as needed, and the arrangement includes, but is not limited to, cross-shaped or ring-shaped arrangements.

[0009] In a preferred embodiment of the present invention, the number and location of the microelectrodes are set according to the measurement needs of the actual application; the microelectrodes are placed at the locations where the diffusion layer thickness needs to be measured.

[0010] In a preferred embodiment of the present invention, a conductive path exists within the substrate of the circular electrode to electrically connect with the microelectrode, and the surface electrode is configured with reference to the structural and dimensional features of the corresponding electroplated cathode surface, including features such as positioning edges / mouths.

[0011] In a preferred embodiment of the present invention, the three-electrode measurement system further includes a power supply board, which is attached to the disc electrode and placed in the electroplating tank. The microelectrode in the disc electrode is electrically connected to the outside through the power supply board. The surface of the surface electrode in the disc electrode is set with reference to the structure and size characteristics of the corresponding electroplating cathode surface. The surface electrode is powered with reference to the power supply method of the corresponding electroplating cathode surface through the disc-level electroplating equipment.

[0012] More preferably, the power supply board includes, but is not limited to, conductive materials such as PCB boards, silicon wafers, and copper sheets.

[0013] More preferably, the power supply board has spring contacts distributed on it, each corresponding to one of the positions of the plurality of microelectrodes, providing independent electrical connections for the microelectrodes.

[0014] In a preferred embodiment of the present invention, the disc electrode is a disc or a rectangular plate, the rectangular plate is a ceramic substrate or a packaging carrier, and the disc has a diameter of 4-12 inches, which can be compatible with the disc clamping device of the disc-level electroplating equipment of the corresponding size.

[0015] In a preferred embodiment of the present invention, the microelectrode and the surface electrode are made of conductive metal, including but not limited to Ti, Cu, Au and Pd. The microelectrode and the surface electrode are fabricated on a substrate by at least one semiconductor process selected from sputtering, evaporation, etching and bonding. The substrate is one of silicon, glass, ceramic and organic substrate.

[0016] In a preferred embodiment of the present invention, the electroplating apparatus may be a horizontal electroplating tank apparatus or a rack electroplating apparatus.

[0017] To achieve the above objectives, a second technical solution of the present invention is: a measurement method for in-situ evaluation of the mass transfer capability of wafer-level electroplating equipment, comprising the following steps:

[0018] (1) Prepare copper plating solution;

[0019] (2) The circular electrode and the power supply board are combined and installed in the electroplating tank of the circular electroplating equipment;

[0020] (3) After the test system is powered on, measure the cathodic polarization curves of each microelectrode and surface electrode of the circular electrode; based on the cathodic polarization curves, extract the limiting diffusion current of each microelectrode point and the surface electrode; and use the formula δ=nFADC / i (n—charge number of the reaction, F—Faraday constant, A—electrode area, D—Cu) to measure the current. 2+ diffusion coefficient, C—Cu 2+ The concentration of the diffusion layer (i—limiting diffusion current, δ—diffusion layer thickness) is used to convert the limiting diffusion current into the diffusion layer thickness. Based on the obtained diffusion layer thickness, the mass transfer capability of the wafer-level electroplating process can be evaluated under the same latitude (providing a unified evaluation standard for the mass transfer capability of electroplating equipment).

[0021] The smaller the thickness of the diffusion layer, the better the mass transfer capability.

[0022] In a preferred embodiment of the present invention, the copper plating solution in step (1) comprises one or more of the following: anions of sulfates, pyrophosphates, aminosulfonates or alkylsulfonates, chloride ions, copper ions, hydrogen ions, etc.

[0023] The measurement results based on the composition of the copper plating solution can be used to independently evaluate the mass transfer capability of the electroplating equipment. Based on this, the mass transfer capability of the electroplating solution formulation can be evaluated and analyzed.

[0024] In a preferred embodiment of the present invention, the cathode polarization curve in step (3) can be an LSV curve obtained by linear scanning voltammetry, an it curve obtained by potentiostatic method, or a cyclic voltammetry curve obtained by cyclic voltammetry, etc.

[0025] In a preferred embodiment of the present invention, the wafer-level electroplating process in step (3) includes electroplating processes such as wafer planar electroplating, copper damask interconnect electroplating, and TSV / TGV via copper electroplating. The electroplating solution formulation, circulation and stirring, spraying, current density, and other environmental parameters are set according to the corresponding process flow.

[0026] In a further preferred embodiment, the surface electrode of the copper damask interconnect electroplating process also needs to be provided with multiple microgrooves and vias, and multiple microelectrodes embedded in the surface electrode are disposed on the bottom surface of the microgrooves and vias; the surface electrode of the TSV / TGV hole copper electroplating process also needs to be provided with TSV / TGV holes, and multiple microelectrodes embedded in the surface electrode are disposed on the bottom surface of the TSV / TGV holes; the microelectrodes are embedded in the surface electrode but are not in contact with the sidewall seed layer / disc surface seed layer and are electrically insulated, and are electrically led out independently relative to the disc surface electrode.

[0027] More preferably, the copper plating solution used in the copper damask interconnect electroplating process and the TSV / TGV hole electroplating copper process further includes one or a combination of several of the following: 1-50 ml / L inhibitor, 1-50 ml / L leveling agent, and 1-50 ml / L accelerator. The accelerator comprises sodium polydithiopropane sulfonate, sodium thiopropane sulfonate, sodium phenyl dithiopropane sulfonate, sodium dimethylformamide propane sulfonate, sodium 3-(benzothio-2-thio)propane sulfonate, and sodium 3-thio-1- The inhibitor comprises one or more of sodium propanesulfonate and dimethyl dithiomethylamine sulfonic acid, wherein the inhibitor comprises one or more of polyethylene glycol, fatty alcohol alkoxylates, and ethylene oxide-propylene oxide block copolymers with molecular weights of 400, 1000, 6000, and 20000, respectively, and the leveling agent is one or more of thiourea compounds, alkylpyridine compounds, and nicotinic acid green, as well as one or more of fatty alcohol polyoxyethylene ether series, ether series, and emulsifier series with different molecular weights.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. This invention enables independent in-situ measurement and characterization of the mass transfer capability of a wafer-level electroplating process;

[0030] 2. This invention can perform in-situ measurement and characterization of the mass transfer capability of electroplating processes such as wafer planar electroplating, copper damask interconnect electroplating, and TSV / TGV via copper electroplating.

[0031] 3. This invention supports the design and development of electroplating equipment mass transfer systems, electroplating additives and formulations. Attached Figure Description

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] Figure 1 This is a front view of the circular electrode in Embodiment 1 of the present invention;

[0034] Figure 2 This is a cross-sectional view of the circular electrode in Embodiment 1 of the present invention;

[0035] Figure 3 This is a flowchart illustrating the fabrication process of the disc electrode in Embodiment 1 of the present invention.

[0036] Figure 4 This is a schematic diagram of the measurement system structure in Embodiment 1 of the present invention;

[0037] Figure 5 This is a schematic diagram of the power supply board structure in Embodiment 1 of the present invention;

[0038] Figure 6 This is a schematic diagram of the assembled structure of the circular electrode and power supply board in Embodiment 1 of the present invention;

[0039] Figure 7 This is a schematic diagram of the application of the measurement system in Embodiment 1 of the present invention on a rack plating machine.

[0040] Figure 8 The following are typical LSV curves obtained by the measurement system in Embodiment 1 of the present invention: a is a typical LSV curve diagram of a surface electrode, and b is a typical LSV curve diagram of a microelectrode.

[0041] Figure 9 This is a schematic cross-sectional view of a circular electrode used in the measurement of a copper damascus interconnect electroplating process in Embodiment 2 of the present invention.

[0042] Figure 10 This is a flowchart of the wafer electrode fabrication process used in the measurement of copper damascus interconnect electroplating process in Embodiment 2 of the present invention.

[0043] Figure 11 This is a schematic diagram of the cross-sectional view of the circular electrode used for measuring the copper plating process of TSV holes in Embodiment 2 of the present invention;

[0044] Figure 12 This is a process flow diagram of the wafer electrode used for measuring the copper plating process of TSV holes in Embodiment 2 of the present invention.

[0045] Figure 13 This is a schematic diagram of the application of the measurement system in Embodiment 3 of the present invention on a horizontal electroplating machine.

[0046] In the diagram: 100-Disc electrode; 110-Microelectrode; 120-Surface electrode; 130-Air gap; 140-Insulating layer; 150-Copper pillar; 160-Copper pad; 170-Substrate; 200-Power supply board; 210-Spring contact; 220-Wiring layer; 230-Substrate; 231-Positioning cylinder; 232-Cylindrical nut; 233-Plastic bolt; 234-Positioning block; 235-Connector; 300-Disc electrode; 301-Surface electrode; 302-T SV hole; 304 - adhesive; 310 - microelectrode; 400 - disc electrode; 401 - surface electrode; 402 - microgroove; 403 - via; 404 - silica dielectric layer; 405 - silica dielectric layer; 410 - microelectrode; 500 - reference electrode; 600 - electroplating solution; 700 - anode; 800 - power supply board; 810 - spring contact; 900 - horizontal electroplating tank; 910 - conductive contact; 1000 - rack plating tank; 1010 - rack plating fixture. Detailed Implementation

[0047] The present invention will be further described below with reference to the accompanying drawings and embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0048] Example 1

[0049] This embodiment will demonstrate a specific method for measuring and evaluating the mass transfer capability of a wafer-level electroplating equipment using the measurement system design proposed in this invention.

[0050] Provide a circular electrode 100, for reference Figure 1 , Figure 2The circular electrode 100 has multiple microelectrodes 110 and surface electrodes 120 on its surface. The microelectrodes 110 have a diameter of 10 μm, and there is an air gap 130 between the microelectrodes 110 and the surface electrodes 120, making each microelectrode 110 electrically insulated from the surface electrode 120. A conductive path exists within the substrate 170 of the circular electrode 100, electrically connected to the microelectrodes 110. The shape and surface pattern of the surface electrode 120 are consistent with the shape and surface pattern of the circular wafer used in the actual surface electroplating process. In this embodiment, the actual substrate wafer diameter is 200 mm. Referring to the positioning design of a 200 mm diameter wafer in the corresponding electroplating process, the surface electrode 120 also has a positioning opening.

[0051] The substrate material of the disc electrode 100 is silicon.

[0052] Reference Figure 3 A process flow for fabricating a wafer electrode is provided, including the following steps:

[0053] Step a: Deep silicon etch holes on the substrate 170 of the wafer;

[0054] Step b: Deposit a silicon dioxide insulating layer, then sputter Ti / Cu as a seed layer;

[0055] Step c: Deposit Cu, fill the holes, and pattern copper pad 160 on the surface. The copper pad 160 and copper pillar 150 form a conductive path.

[0056] Step d: Thin the back side of the substrate 170 of the wafer down to the insulating layer, then deposit another layer of silicon dioxide insulating layer, and then perform DRIE plasma etching to etch micropores to expose conductive paths;

[0057] Step e: Deposit a Cu metal layer;

[0058] Step f: Photolithography and etching to form microelectrode 110 and surface electrode 120.

[0059] The copper pad is slightly larger than the microelectrode, and its purpose is to provide a larger operating range for the electrical leads of the microelectrode.

[0060] It should be noted that the arrangement and number of microelectrode arrays can be changed according to testing requirements. In this embodiment, the microelectrode array is arranged in a cross shape, while in other embodiments, the microelectrode array can also be arranged in a ring shape, etc.

[0061] Reference Figure 4 The power supply board 200 includes spring contacts 210 distributed on the substrate, and the spring contacts 210 are in one-to-one contact with the microelectrodes 110 on the disc electrode 100 to form an independent electrical connection.

[0062] The power supply board 200 is a custom PCB board, see reference. Figure 4 — Figure 6 A power supply board structure is provided, using FR4 as the PCB substrate material. A wiring layer 220 and pads are deposited on the substrate 230, and spring contacts 210 are reflow soldered onto the pads. The spring contacts 210 correspond one-to-one with the microelectrodes 110 on the circular electrode 100, providing electrical connection between the microelectrodes 110 and the external environment. A positioning cylinder 231, a positioning block 234, and a cylindrical nut 232 are glued to the same side as the spring contacts 210 for positioning and clamping the power supply board 200 when it is tightly attached to the circular electrode 100. The positioning cylinder and other adhesive components can be made of corrosion-resistant plastics such as polytetrafluoroethylene (PTFE). Connectors 235 are soldered onto the power supply board 200 for connection to external devices.

[0063] The following reference Figure 6 This describes one possible combination of the disc electrode 100 and the power supply board 200: The side of the power supply board 200 with the spring contacts 210 faces upwards, while the side of the disc electrode 100 with the microelectrodes 110 faces upwards, and it is placed on the positioning block 234. The positioning ports on the disc electrode 100 engage with the positioning cylinders 231 of the power supply board 200. Other positioning cylinders position the disc electrode 100 according to a six-point positioning principle. At this point, the spring contacts 210 and the copper pads 160 on the back of the disc electrode are in one-to-one contact and achieve a certain amount of compression. Finally, the cylindrical nuts 232 on the power supply board 200 are tightened with corrosion-resistant plastic bolts 233 to further fix the relative position of the disc electrode 100 and the power supply board 200. At this point, the microelectrodes 110 form an independent electrical connection with the outside world through the copper pillars 150, copper pads 160, spring contacts 210, wiring layer 220, and connectors 235.

[0064] In this embodiment, the reference electrode 500 is a saturated calomel electrode.

[0065] Taking a rack plating electroplating machine as an example, refer to Figure 7 , Figure 8 The methods for measuring and characterizing mass transfer capacity are described below.

[0066] First, use 50 g / L H2SO4 and 40 g / L Cu 2+ 60ppm Cl - Prepare the basic copper plating solution.

[0067] Secondly, after assembling the circular electrode 100 and the power supply board 200 according to the above method, the assembled unit is installed in the electroplating tank, such as... Figure 7As shown, the circular electrode 100 is the working electrode, the anode 700 in the electroplating tank is the counter electrode, and the saturated calomel electrode is the reference electrode 500, forming a three-electrode system. The microelectrode 110 is electrically connected to the outside through the power supply board 200, and the circular electrode 120 is powered by the circular electroplating equipment, referring to the power supply method of the corresponding electroplating cathode surface.

[0068] Secondly, LSV measurements were used to extract the polarization current versus polarization potential curve, thus extracting the current under mass transfer-limited conditions. After energizing the three-electrode system consisting of the disc electrode 100, anode 700, and reference electrode 500, a multi-channel electrochemical workstation was used to simultaneously measure the cathodic polarization curves of each microelectrode and surface electrode, such as... Figure 8 As shown. From Figure 8 As shown above, the average current on the ordinate corresponding to the stable segment of the curve is the extracted limiting diffusion current. Based on the cathodic polarization curve, the limiting diffusion current at each microelectrode 110 point and the surface electrode 120 is extracted using the formula δ=nFADC / i (n—charge number of the reaction, F—Faraday constant, A—electrode area, D—Cu). 2+ diffusion coefficient, C—Cu 2+ The concentration of the diffusion layer (i—limiting diffusion current, δ—diffusion layer thickness) is used to convert the limiting diffusion current into the diffusion layer thickness. Based on the obtained diffusion layer thickness, the mass transfer capability of different wafer-level electroplating equipment can be evaluated at the same latitude. A thinner diffusion layer indicates better mass transfer capability.

[0069] Example 2

[0070] This embodiment demonstrates that the measurement system proposed in this invention can also be applied to the measurement and extraction of the mass transfer capabilities of micro- and nano-sized micro-holes and micro-grooves on the cathode surface in TSV / TGV holes and copper damask interconnect electroplating.

[0071] In this embodiment, the difference from Embodiment 1 is that the microelectrode in the wafer electrode is disposed on the bottom surface of the microgroove and via or TSV hole in the copper damask interconnect, embedded therein but not in contact with the sidewall seed layer / wafer surface seed layer, etc., and electrically insulated, and electrically led out independently relative to the wafer surface electrode. The wafer electrode involved in this embodiment is described below.

[0072] A circular electrode 400 is provided for measuring and extracting the mass transfer capacity in the copper damascus interconnect electroplating process. (Refer to...) Figure 9 The circular electrode 400 has vias 403, microgrooves 402, and surface electrodes 401 in a copper damask interconnect on its surface. Microelectrodes 410 are exposed on the underside of the vias 403 and microgrooves 402. Conductive pathways exist inside the circular electrode 400, electrically connected to the microelectrodes 410. The circular electrode 400 can be fabricated based on the circular electrode 100 described in the embodiment. The following describes... Figure 10 The fabrication steps of the wafer electrode 400 are described, including: after the wafer electrode fabrication step f described in Example 1, step g1 is performed to deposit two SiOF (fluorine-doped silicon dioxide) dielectric layers 404 and 405; step h1 is to photolithographically etch vias 403 and microgrooves 402 to expose the underlying microelectrode 410; and step i1 is to pattern and deposit a metal layer to form a surface electrode 401.

[0073] A circular electrode 300 is provided, and its mass transfer capacity is measured and extracted during the TSV hole electroplating process. (Refer to...) Figure 11 The circular electrode 300 has a TSV hole 302 and a surface electrode 301 on its surface. A microelectrode 310 is exposed on the bottom surface of the TSV hole, and a conductive path exists inside the circular electrode 300, electrically connected to the microelectrode 310. The circular electrode 300 can be fabricated based on the circular electrode 100 described in Example 1. The following describes... Figure 12 A method for fabricating a disc electrode 300 is described, comprising: after step f of fabricating the disc electrode 100 as described in Example 1, step g2 is performed, in which adhesive 304 is spin-coated onto the back of the disc with the TSV via features already processed, and the TSV via 302 is patterned to expose it; step h2 is performed, in which the TSV disc is aligned and bonded to the disc electrode with microelectrodes 310 distributed thereon, such that the microelectrodes 310 are located at the bottom of the TSV via 302.

[0074] The mass transfer capacity measurement and characterization method involved in this embodiment is described below, specifically:

[0075] Using the circular electrode 400, and referring to the mass transfer capacity measurement method described in Example 1, the limiting current of the via, the bottom of the micro-groove, and the surface electrode can be extracted, thereby characterizing the mass transfer capacity of the copper damask interconnect electroplating process.

[0076] Using the circular electrode 300, and referring to the mass transfer capacity measurement method described in Example 1, the limiting current of the bottom and surface electrodes of the TSV can be extracted, thereby characterizing the mass transfer capacity of the TSV hole electroplating process.

[0077] During the testing process, the plating solution used was a TSV and damask interconnect plating solution, including 60 g / L sulfuric acid (H2SO4) and 40 g / L copper ions (Cu). 2+ ), 80ppm chloride ions (Cl - The 10ml / L inhibitor, 5ml / L leveling agent, and 3ml / L accelerator were provided by Shanghai Saft Company.

[0078] The mass transfer-limited current obtained under these circumstances is the result of the combined effects of the electroplating equipment's circulation and stirring functions, as well as the electroplating additives.

[0079] The design of the remaining measurement system and the method for measuring mass transfer capacity are the same as in Example 1, and will not be repeated here.

[0080] Example 3

[0081] This embodiment demonstrates that the measurement system proposed in this invention can also be applied to horizontal electroplating equipment.

[0082] The difference between this embodiment and Embodiment 1 is that the shape of the power supply board used in the horizontal electroplating apparatus is adapted to the horizontal electroplating fixture, while other aspects remain unchanged. The following describes the method of using the measurement system design proposed in this invention in a horizontal electroplating apparatus, referring to... Figure 13 The details are as follows:

[0083] First, the basic electroplating solution 600 was prepared according to Example 1.

[0084] Secondly, the power supply board (2) 800 is attached to the disc electrode 100, so that the spring contact (2) 210 contacts the disc electrode 100 and corresponds one-to-one with the microelectrode 110, providing an independent electrical connection. Further, the power supply board (2) 800 and the disc electrode 100 are installed as a whole in the horizontal electroplating equipment, forming a three-electrode system consisting of the disc electrode 100, the anode 700, and the reference electrode 500. The microelectrode forms an electrical connection with the outside through the power supply board (2) 800, and the disc electrode 100 contacts the conductive contact 910, receiving power through the electroplating equipment.

[0085] In this embodiment, the power supply board (2) 800 is a circular double-layer PCB board with cables connected to the back and led out from inside the machine.

[0086] The rest of the design of the measurement system and the method for measuring mass transfer capacity are the same as in Example 1, and will not be repeated here.

[0087] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A measurement system for in-situ evaluation of mass transfer capability in a wafer-level electroplating process, characterized in that, The measurement system is a three-electrode measurement system, including a circular electrode, a reference electrode, and an anode in the electroplating apparatus. Multiple microelectrodes and one surface electrode are disposed on the circular electrode. The microelectrodes are embedded in the surface electrode, and an air gap exists between the microelectrodes and the surface electrode. They are electrically isolated and powered independently. The microelectrodes are arranged in a cross or ring configuration within the surface electrode. A conductive path exists within the substrate of the circular electrode, electrically connecting it to the microelectrodes. The surface electrode is configured with reference to the structural and dimensional characteristics of the corresponding electroplating cathode surface. The materials of the microelectrodes and the surface electrode are conductive metals, including Ti, Cu, Au, and Pd. The microelectrodes and the surface electrode are fabricated on the substrate using at least one semiconductor process selected from sputtering, evaporation, etching, and bonding. The substrate is one of silicon, glass, ceramic, or organic substrate.

2. The measurement system as described in claim 1, characterized in that, The three-electrode measurement system also includes a power supply board, which is attached to the circular electrode and placed in the electroplating tank. The microelectrodes in the circular electrode are electrically connected to the outside through the power supply board. The surface of the surface electrode in the circular electrode is set with reference to the structure and size characteristics of the corresponding electroplating cathode surface. The surface electrode is powered with reference to the power supply method of the corresponding electroplating cathode surface through the circular electroplating equipment. The power supply board includes one of a PCB board, a silicon wafer, and a copper sheet. The power supply board has spring contacts distributed on it, which correspond one-to-one with the positions of the multiple microelectrodes, providing independent electrical connections for the microelectrodes.

3. The measurement system as described in claim 1, characterized in that, The disc electrode is a disc with a diameter of 4-12 inches, compatible with disc clamping devices in disc-level electroplating equipment of the corresponding size.

4. The measurement system as described in claim 1, characterized in that, The electroplating device is a horizontal electroplating device or a rack electroplating device.

5. A measurement method for in-situ evaluation of mass transfer capability in a wafer-level electroplating process based on the measurement system described in any one of claims 1-4, characterized in that, Includes the following steps: (1) Prepare copper plating solution; (2) After combining the disc electrode with the power supply board, install it in the electroplating tank of the disc-level electroplating equipment, and set the electroplating solution formula, circulation and stirring, spraying and current density according to the corresponding process. (3) After the test system is powered on, measure the cathodic polarization curves of each microelectrode and surface electrode of the circular electrode; based on the cathodic polarization curves, extract the limiting diffusion current of each microelectrode point and the surface electrode; and use the formula δ=nFADC / in—the number of charges in the reaction, F—Faraday constant, A—electrode area, D—Cu 2+ diffusion coefficient, C—Cu 2+ The concentration, i—limiting diffusion current, δ—diffusion layer thickness, the limiting diffusion current is converted into diffusion layer thickness, and the mass transfer capability of the wafer-level electroplating process is evaluated based on the obtained diffusion layer thickness.

6. The measurement method as described in claim 5, characterized in that, The cathodic polarization curve in step (3) is one of the following: the LSV curve obtained by linear scanning voltammetry, the it curve obtained by potentiostatic method, or the cyclic voltammetry curve obtained by cyclic voltammetry.

7. The measurement method as described in claim 5, characterized in that, The wafer-level electroplating process in step (3) includes the electroplating processes of wafer planar electroplating, copper damask interconnect electroplating, and TSV / TGV hole copper electroplating.

8. The measurement method as described in claim 7, characterized in that, The copper damascus interconnect electroplating process requires multiple microgrooves and vias on the surface electrode, with multiple microelectrodes embedded in the surface electrode located on the bottom surface of the microgrooves and vias; the TSV / TGV hole copper plating process requires TSV / TGV holes on the surface electrode, with multiple microelectrodes embedded in the surface electrode located on the bottom surface of the TSV / TGV holes; the microelectrodes are embedded in the surface electrode, but are electrically insulated from the sidewall seed layer / disc surface seed layer, and are electrically led out independently relative to the disc surface electrode; the microgrooves and vias on the surface electrode are fabricated using at least one semiconductor process selected from etching, sputtering, evaporation, and bonding.

9. The measurement method as described in claim 7, characterized in that, The copper plating solution for the copper damascus interconnect electroplating process and the TSV / TGV hole electroplating copper process further includes one or a combination of 1-50 ml / L inhibitor, 1-50 ml / L leveling agent, and 1-50 ml / L accelerator; the accelerator includes one or more of sodium polydithiopropane sulfonate, sodium thiopropane sulfonate, sodium phenyl dithiopropane sulfonate, sodium dimethylformamide propane sulfonate, sodium 3-(benzothio-2-thio)propane sulfonate, sodium 3-thio-1-propane sulfonate, and dimethyl dithiomethylamine sulfonic acid; the inhibitor includes one or more of polyethylene glycol, fatty alcohol alkoxylates, and ethylene oxide-propylene oxide block copolymers with molecular weights of 400, 1000, 6000, and 20000; the leveling agent is one or more of thiourea compounds, alkylpyridine compounds, and nicotinic green.

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