Glass via fill method based on transition metal layer and glass substrate

Abstract

The application discloses a glass via hole filling method based on a transition metal layer and a glass substrate, and comprises the following steps: providing a glass substrate with a via hole; cleaning and performing a hole wall activation treatment on the via hole; preparing a transition metal layer on the inner wall of the via hole; performing electroplating hole filling on the via hole; and performing a planarization treatment on the glass substrate. The transition metal layer is prepared on the inner wall of the via hole to connect the glass substrate and the subsequent filling metal, effectively alleviates the interface delamination risk caused by thermal mismatch, guarantees the continuity of the high aspect ratio via hole conductive path, simultaneously adapts to the large-scale production demand, and significantly reduces the process cost and equipment investment.

Description

Technical Field

[0001] This invention relates to the field of glass transition plate technology, and in particular to a glass through-hole filling method based on a transition metal layer and a glass substrate. Background Technology

[0002] With the rapid development of technologies such as 3D system-in-package, RF front-end devices and MEMS sensors, through glass via (TGV) technology has become the core technology solution for vertical interconnection of glass adapters due to the excellent high-frequency and low-loss characteristics of glass materials, the matching thermal expansion coefficient with silicon and the advantages of low cost. The quality of its metallization filling directly determines the electrical performance and long-term reliability of the packaged device.

[0003] The current TGV metallization process generally adopts the technical route of "hole wall activation - physical vapor deposition (PVD) sputtering of multilayer metal - electroplating copper filling": first, the glass via is cleaned and plasma activated, then Ti, Cr and other adhesion layers and Cu conductive seed layer are deposited sequentially on the inner wall of the via through the PVD process, and finally copper is electroplated to fill the via using the seed layer as a conductive path to achieve electrical interconnection between the front and back of the glass substrate.

[0004] However, this process has inherent interfacial bonding defects: glass is an insulating, inert material without free electrons, and its coefficient of thermal expansion differs significantly from that of metallic copper (glass has a thermal expansion coefficient of 3~8 ppm / ℃, while metallic copper has a thermal expansion coefficient of approximately 16.7 ppm / ℃). During temperature cycling processes such as electroplating annealing and subsequent reflow soldering, thermal mismatch between the two will accumulate large shear stress and radial stress at the glass-metal interface, which can easily lead to delamination between the copper pillar and the hole wall, substrate warping, or even copper pillar breakage, severely reducing the long-term reliability of the packaging structure.

[0005] For challenging through-holes with aspect ratios ≥10:1, the aforementioned process suffers from uneven seed layer coverage. PVD sputtering particles exhibit linear propagation, resulting in a seed layer thickness at the bottom and lower sidewalls of the through-hole that is only 1 / 3 of the surface thickness or even discontinuous. This leads to weak or non-conductive conductive paths at the bottom of the hole during electroplating, easily causing defects such as insufficient filling and open circuits. To address this coverage issue, the industry has attempted to use atomic layer deposition (ALD) to prepare the seed layer. While this improves the uniformity of hole wall coverage, ALD equipment is expensive, has a slow deposition rate, and extremely low throughput, making it difficult to meet the cost and efficiency requirements for large-scale mass production. If the overall seed layer thickness is increased or the PVD bias power is increased to compensate for coverage defects, it will lead to increased substrate surface roughness and poorer metal layer wettability, which in turn exacerbates the formation of voids within the holes during electroplating, further reducing product yield.

[0006] Therefore, how to design a glass via filling method that can satisfy both the via filling quality and electrical conductivity is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] To address the shortcomings of existing glass through-hole metallization processes, such as poor reliability and uneven coverage, as well as the deficiencies of laser-driven hole-opening technology, this invention proposes a glass through-hole filling method and glass substrate based on a transition metal layer. A transition metal layer is prepared on the inner wall of the through-hole to connect the glass substrate and the subsequent filling metal, effectively mitigating the risk of interface delamination caused by thermal mismatch, ensuring the continuity of the conductive path of high aspect ratio through-holes, and adapting to the needs of large-scale mass production, while significantly reducing process costs and equipment investment.

[0008] The technical solution adopted in this invention is to design a glass via filling method based on a transition metal layer, comprising the following steps: Provide a glass substrate with through holes; The through-holes are cleaned and their walls are activated. A transition metal layer is prepared on the inner wall of the through hole; Electroplating is performed to fill the through holes; Planarization is performed on the glass substrate.

[0009] This design incorporates a transition metal layer between the glass substrate and the filler metal. This transition layer connects two materials with significantly different properties, helping to alleviate thermal mismatch stress during subsequent temperature cycling and reducing the risk of interface delamination. Compared to directly fabricating a conductive layer on the glass surface, this transition layer provides a more reliable adhesion base for subsequent electroplating, contributing to improved overall bonding strength and long-term reliability of the through-hole filling structure.

[0010] In some embodiments of the present invention, a transition metal layer is prepared on the inner wall of the through hole, including: The reaction is carried out in a liquid phase environment at 40~50℃ for 2~3 hours to form a transition metal layer on the inner wall of the through hole; It is then immersed in a solution containing palladium catalyst for activation treatment, soaking at room temperature for 3-5 minutes.

[0011] This design employs liquid phase deposition (LPD) to prepare the transition metal layer. A thin film is generated in situ on the hole wall using a chemical reaction, effectively improving the uniformity of coverage within high aspect ratio vias and mitigating the "shadowing effect" present in physical vapor deposition. Activation treatment with a palladium catalyst solution helps introduce catalytically active sites onto the transition metal layer surface, providing the necessary conductive triggering conditions for subsequent flash plating steps and ensuring the initial uniformity of metal deposition.

[0012] Based on this, after the transition metal layer is prepared, the surface of the transition metal layer is first flash plated, and then the through holes are electroplated and filled using a process that combines bridging electroplating and hole-filling electroplating.

[0013] This design utilizes a flash plating step to rapidly form a dense and continuous initial conductive layer on the surface of the transition metal layer, compensating for potential conductivity deficiencies in the liquid phase deposition layer and ensuring uniform current distribution during subsequent electroplating. The use of bridging electroplating for initial deposition helps establish a stable conductive network at the bottom of the via, suppressing excessively rapid deposition at the via opening. Subsequent via-filling electroplating then utilizes the established conductive pathways to quickly fill the remaining space; the combination of these two methods helps achieve void-free via filling.

[0014] Furthermore, the flash plating is a horizontal flash plating, using a DC power supply with a current density of 1~2A / dm² and a plating time of 10~15min; The process parameters for the bridging electroplating stage are as follows: a pulse power supply is used, the forward current density is 0.1~0.3A / dm², the ratio of forward energizing time to reverse energizing time is 1:3~1:5, and the electroplating time is 3~4h. The process parameters for the hole-filling electroplating stage are as follows: DC power supply, current density of 1~2A / dm², and electroplating time of 70~90min.

[0015] Horizontal flash plating helps avoid uneven plating thickness caused by gravity when the substrate is placed vertically, improving the consistency of plating on the substrate surface and near the vias. The bridging plating stage uses a pulsed power supply with a specific forward / reverse time ratio. The forward current helps metal deposit at the bottom, while the reverse current helps dissolve excess plating at the vias, further suppressing the "capping effect" and guiding metal growth from bottom to top. Switching to a high-current DC mode during the via-filling plating stage helps improve filling efficiency and shorten the process cycle.

[0016] In some embodiments of the present invention, a transition metal layer is prepared on the inner wall of the through hole, including: An auxiliary substrate is bonded to the side of the glass substrate away from the through-hole opening; The through-holes are filled using a supercritical carbon dioxide-assisted chemical plating process, in which organometallic compounds are dissolved in supercritical carbon dioxide to form a transition metal layer.

[0017] This design provides a stable support and conductive circuit for electroless plating and subsequent electroplating processes by bonding an auxiliary substrate to the back of the glass substrate, which helps reduce warpage of the thin glass substrate. Utilizing the excellent permeability and mass transfer capabilities of supercritical carbon dioxide fluid, organometallic compounds can be delivered to every corner of the high aspect ratio vias, achieving uniform electroless plating deposition on the inner walls of the vias, thereby forming a continuous and dense transition metal layer, which is particularly suitable for metallization of deep-hole structures.

[0018] Based on this, the through holes are electroplated and filled, including: The through holes are filled by electroplating using a DC electroplating process. After the holes are filled, remove the auxiliary substrate.

[0019] This design uses direct current electroplating to fill holes after forming a transition metal layer through chemical plating. The process is mature and stable, and the deposition rate is controllable, which helps to quickly complete the metallization filling of through holes.

[0020] Furthermore, the current density for DC hole-filling electroplating is 1~2A / dm², and the electroplating time is 70~90min.

[0021] Appropriate current density helps maintain stable copper ion deposition, avoiding burning due to excessive current or inefficiency due to insufficient current; combined with a specific duration, it can ensure that the via is completely filled with metallic copper, balancing filling quality and production efficiency.

[0022] Furthermore, the pore wall activation treatment is plasma treatment, with the following process parameters: using a box-type plasma device, a vacuum degree of 0.5~0.9Pa, introducing an argon-oxygen mixture, a power of 1~3kW, and a treatment time of 1~3min.

[0023] This design employs plasma treatment with specific parameters to effectively remove organic contaminants and weak boundary layers from the inner walls of the vias, and introduces active functional groups (such as hydroxyl groups) onto the glass surface through high-energy particle bombardment. This significantly improves the hydrophilicity of the glass surface, enhances the physical and chemical bonding between the subsequent transition metal layer and the glass substrate, and lays the foundation for improving interfacial adhesion.

[0024] Furthermore, the diameter of the through hole is 20~50μm, and the depth-to-width ratio is ≥10:1.

[0025] This design clarifies the specific technical scenarios to which this invention is applicable. For through-holes with small diameters and large aspect ratios, traditional physical vapor deposition and simple electroplating processes face significant challenges in terms of coverage and filling. This method, through the introduction of a transition metal layer and corresponding process combinations, can effectively address the filling requirements of such high aspect ratio structures, thus expanding the application scope of the process.

[0026] Furthermore, the thickness of the transition metal layer is 300~500nm.

[0027] This thickness range strikes a balance between interfacial bonding performance and process cost. An excessively thin transition layer may fail to effectively block thermal mismatch stress or provide a continuous conductive path, while an excessively thick transition layer may increase process complexity and cost, and even affect the effective aperture of vias. A thickness of 300–500 nm maintains good process economy and structural adaptability while ensuring sufficient bonding strength and conductivity.

[0028] The present invention also provides a glass substrate comprising: A glass substrate body having through holes; A transition metal layer is disposed on the surface of the hole wall of the through hole, and the transition metal layer is tightly attached to the hole wall of the through hole; A metal filler layer is disposed in the through hole and located on the inner peripheral side of the transition metal layer, and the metal filler layer is bonded to the inner peripheral surface of the transition metal layer. The transition metal layer and the metal filler layer fill the internal space of the through hole.

[0029] The metal filler layer within the through-hole of the glass substrate is connected to the hole wall by a transition metal layer, resulting in a tight interface and good thermal shock resistance. Simultaneously, the dense filling within the through-hole provides excellent electrical conductivity, meeting the electrical performance and reliability requirements of high-performance 3D packaging for glass adapter boards. This makes it suitable for manufacturing precision devices such as 5G communications and MEMS sensors.

[0030] In some embodiments, the metal filler layer consists of a flash-plated copper layer and an electroplated copper layer located on the inner periphery of the flash-plated copper layer, the flash-plated copper layer covering the inner periphery of the transition metal layer.

[0031] In other embodiments, the metal filler layer is a single electroplated copper layer.

[0032] Compared with the prior art, the present invention has at least one of the following beneficial effects: 1. By setting a transition metal layer on the inner wall of the glass through-hole, an interface buffer structure is formed between the glass substrate and the subsequent filler metal, which alleviates the thermal mismatch stress caused by the difference in the thermal expansion coefficients of the two, reduces the risk of delamination and cracking of the hole wall and the filler metal under temperature cycling conditions, and improves the long-term service reliability of the glass transition plate; at the same time, the transition metal layer provides a uniform adhesion substrate for subsequent electroplating filler, solves the problem of filling circuit break caused by uneven seed layer coverage in high aspect ratio through-holes, and is especially suitable for high-difficulty through-hole filling requirements with an aspect ratio ≥10:1; 2. The transition metal layer is prepared by liquid phase deposition, which uses chemical reaction to grow the film in situ on the hole wall. This effectively improves the uniformity of film coverage on the inner wall of high aspect ratio through holes and avoids the discontinuity of film at the bottom of the hole and the lower part of the sidewall caused by the "shadow effect" of physical vapor deposition. At the same time, the liquid phase deposition process does not require a high vacuum environment, and the equipment investment and maintenance costs are much lower than those of atomic layer deposition, making it suitable for large-scale mass production. 3. A transition metal layer is prepared by supercritical carbon dioxide-assisted chemical plating. The excellent permeability and mass transfer capability of supercritical fluid are used to transport organometallic compounds to various regions of the through hole, achieving uniform coating on the inner wall of the deep hole and further ensuring the continuity of the conductive path of the high aspect ratio through hole. This process does not require complex vacuum sputtering equipment and the post-plating treatment process is simple, which greatly reduces the complexity of the process and the investment in equipment. Attached Figure Description

[0033] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein: Figure 1 This is a schematic diagram of the preparation of the transition metal layer in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of flash plating in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of electroplating filling in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of CMP polishing in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the glass substrate of Embodiment 2 of the present invention; Figure 6 This is a schematic diagram of the auxiliary substrate of Embodiment 2 of the present invention; Figure 7 This is a schematic diagram of the preparation of the transition metal layer in Embodiment 2 of the present invention; Figure 8 This is a schematic diagram of electroplating filling in Embodiment 2 of the present invention; Figure 9 This is a schematic diagram of CMP grinding in Embodiment 2 of the present invention. Detailed Implementation

[0034] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0035] See Figures 1 to 4As shown, this invention provides a glass via-hole filling method based on a transition metal layer, which is particularly suitable for glass via-hole filling scenarios with an aspect ratio ≥ 10:1. First, a basic filling process is performed: the glass substrate 100 is first cleaned and the via walls are activated. This process removes contaminants from the via walls and introduces active groups, improving the adhesion of the subsequent transition metal layer. Then, a transition metal layer 200 is prepared on the inner wall of the via 110. This transition metal layer 200 connects the glass substrate 100 and the subsequent filling metal, alleviating the thermal mismatch stress caused by the difference in their coefficients of thermal expansion. Next, the via 110 is electroplated to fill the via, forming a dense metal filling layer 300 within the via 110. Finally, the glass substrate 100 is planarized to complete the surface finishing.

[0036] In practical applications, borosilicate glass substrates with through holes of 20~50μm in diameter can be selected as the processing object. The thermal expansion coefficient of this material is close to that of silicon, which meets the process compatibility requirements of subsequent three-dimensional packaging.

[0037] The pore wall activation treatment can be performed using a box-type plasma device, with the vacuum level controlled at 0.5~0.9Pa, an argon-oxygen mixture introduced, the power set at 1~3kW, and the treatment time at 1~3min. High-energy plasma particles bombard the pore wall, which can effectively remove organic contaminants and weak boundary layers from the pore wall, and introduce functional groups such as active hydroxyl groups on the glass surface, significantly improving the wettability and interfacial bonding of the subsequent transition metal layer 200.

[0038] The transition metal layer 200 can be prepared by liquid phase deposition (LPD) process, reacting in a liquid phase environment of 40~50℃ for 2~3 hours to form a uniform metal oxide film on the inner wall of the through hole 110. Then, it is immersed in a solution containing palladium catalyst for activation treatment, soaking at room temperature for 3~5 minutes to introduce catalytic active sites on the film surface. The thickness of the transition metal layer 200 can be controlled at 300~500nm, taking into account both interfacial bonding performance and process cost.

[0039] The electroplating and via filling process can adopt a stepped process of "flash plating + bridging plating + via filling plating": First, horizontal flash plating is performed using a DC power supply with a current density of 1~2A / dm² and a plating time of 10~15min, which quickly forms a dense and continuous initial conductive layer 210 on the surface of the transition metal layer; then, bridging plating is performed using a pulse power supply with a forward current density of 0.1~0.3A / dm², a forward energizing time to reverse energizing time ratio of 1:3~1:5, and a plating time of 3~4h, which guides the metal to grow upward from the bottom of the via 110 and inhibits premature sealing of the via opening; finally, via filling plating is performed using a DC power supply with a current density of 1~2A / dm² and a plating time of 70~90min, which quickly fills the remaining pores, taking into account both filling quality and process efficiency, and forming a dense metal filling layer 300 in the via 110.

[0040] See Figures 1 to 4 As shown, this invention provides Example 1, which uses a liquid phase deposition process to prepare the transition metal layer 200 for filling. The specific steps are as follows: Step 1: Prepare a glass substrate 100. The glass substrate 100 has a through hole 110 with a diameter of 50 μm. Step 2: Cleaning of glass through-holes + activation of hole walls; The glass substrate 100 is placed in an ultrasonic cleaning tank filled with deionized water to remove surface dust and processing debris, and then dried with high-purity nitrogen and placed in a clean and dry environment for later use. The pore wall activation is performed using a box-type plasma device. Before the process, the chamber is evacuated to a vacuum of 0.5~0.9Pa, and an argon-oxygen mixture with a volume ratio of 1:1~2:1 is introduced as the process gas. The power supply is set to 1~3kW. During the process, high-energy plasma particles bombard the hole walls, removing residual organic contaminants while introducing a large number of active hydroxyl groups on the glass surface, thereby improving the wettability and adhesion of the subsequent transition metal layer 200. Step 3: Prepare the transition metal layer (LPD molding); The reaction is carried out in a liquid phase environment at 40~50℃ for 2~3 hours to form a transition metal layer 200 of metal oxide material on the inner wall of the through hole 110; then it is immersed in a solution containing palladium catalyst for activation treatment, and soaked at room temperature for 3~5 minutes to introduce catalytic active sites on the surface of the transition metal layer 200; the thickness of the transition metal layer 200 is 300~500nm. Step 4: Perform chemical flash plating using an acidic copper sulfate plating solution; A horizontal flash plating process is adopted, using a DC power supply with a current density of 1~2A / dm² and a plating time of 10~15min. A dense and continuous initial conductive layer 210 is formed on the surface of the transition metal layer 200, providing a basis for uniform current distribution for subsequent electroplating. Step 5: Using an acidic copper sulfate plating solution, a bridging and filling electroplating method is adopted to form a dense metal filling layer 300 in the through hole 110. The bridging electroplating stage is performed as follows: a pulse power supply is used, with a forward current density of 0.1~0.3A / dm², a forward current-to-reverse current ratio of 1:3~1:5, and an electroplating duration of 3~4 hours. During forward current, copper ions preferentially deposit at the bottom of the via, while during reverse current, excess plating at the via opening is dissolved, effectively preventing premature sealing of the via opening and guiding metal growth from bottom to top. The bridging electroplating stage ends when the plating has grown to 1 / 3~1 / 2 of the via depth. Perform the hole-filling electroplating stage: switch to DC power supply, current density of 1~2A / dm², electroplating time of 70~90min; use the established conductive network to quickly fill the remaining pores, and monitor the current stability in real time to ensure uniform deposition rate. Step 6: CMP flattening process; Planarization was achieved using chemical mechanical polishing equipment. After polishing, the substrate surface was rinsed with deionized water to thoroughly remove residual polishing liquid and abrasive debris. Finally, it was dried with high-purity nitrogen gas to obtain a glass substrate 100 with a smooth surface and densely filled through holes.

[0041] See Figures 5 to 9 As shown, considering the requirements of process compatibility and cost control for different application scenarios, the preparation process of the transition metal layer can be optimized accordingly. One optimized scheme is to prepare the transition metal layer 200 using a supercritical carbon dioxide-assisted chemical plating process. In this process, an auxiliary substrate 400 is first bonded to the side of the glass substrate 100 opposite to the opening of the via 110. A single-sided copper-clad ceramic substrate is selected, with the copper-clad side facing the glass substrate 100, providing stable support and a conductive circuit for subsequent chemical plating and electroplating. Then, a supercritical carbon dioxide-assisted chemical plating process is used to dissolve organometallic compounds in supercritical carbon dioxide, utilizing its strong permeability to achieve uniform deposition within a high aspect ratio structure, forming the transition metal layer 200 on the inner wall of the via 110. Subsequently, a DC electroplating process is used to fill the via 110, quickly completing the metallization process. After filling, the auxiliary substrate 400 is removed, and finally, planarization is performed to obtain the finished glass substrate 100. This scheme does not require complex vacuum sputtering equipment, simplifies the process, and has lower costs, making it suitable for large-scale mass production.

[0042] See Figures 5 to 9 As shown, the present invention also provides Example 2, which uses a process route of supercritical carbon dioxide-assisted chemical plating to prepare a transition metal layer 200 to achieve filling. The specific steps are as follows: Step 1: Prepare a glass substrate 100. The glass substrate 100 has a through hole 110 with a diameter of 20 μm. Step 2: Cleaning of glass through-holes + activation of hole walls; The glass substrate 100 is placed in an ultrasonic cleaning tank filled with deionized water to remove surface dust and processing debris, and then dried with high-purity nitrogen and placed in a clean and dry environment for later use. The pore wall activation is performed using a box-type plasma device. Before the process, the chamber is evacuated to a vacuum of 0.5~0.9Pa, and an argon-oxygen mixture with a volume ratio of 1:1~2:1 is introduced as the process gas. The power supply is set to 1~3kW. During the process, high-energy plasma particles bombard the hole walls, removing residual organic contaminants while introducing a large number of active hydroxyl groups on the glass surface, thereby improving the wettability and adhesion of the subsequent transition metal layer 200. Step 3: Bond an auxiliary substrate 400 to the side of the glass substrate 100 opposite to the opening of the through hole 110. A single-sided copper-clad ceramic substrate is selected as the auxiliary substrate 400, with the copper-clad side facing the glass substrate 100. Temporary bonding adhesive is used to bond the auxiliary substrate to the glass substrate, providing stable support and conductive path for subsequent chemical plating and electroplating. Step 4: Use supercritical CO2-assisted chemical plating to fill the holes; Organometallic compounds are dissolved in supercritical carbon dioxide using a high-pressure carbon dioxide delivery device and a high-pressure reactor. The temperature is 40-60℃, the pressure range is 10 MPa - 20 MPa, and the stirring speed is typically 500-1500 rpm. The chemical copper plating solution uses 0.05-0.16 mol / L of acidic copper sulfate and 0.1-0.3 mol / L of sodium hypophosphite. Utilizing the strong permeability of supercritical fluid to micro- and nano-pores, uniform deposition is achieved within a high aspect ratio structure, forming a transition metal layer 200 on the inner wall of the through-hole 110. This method can obtain a metal layer with finer grains and better coverage, with the thickness of the transition metal layer 200 being 300-500 nm. Step 5: Perform DC hole-filling electroplating using acidic copper sulfate plating solution; The process employs DC electroplating with a current density of 1~2A / dm² and an electroplating time of 70~90min. The conductive path provided by the auxiliary substrate 400 is used to uniformly deposit and fill the through holes with metallic copper. Step 6: Peel off the auxiliary substrate 400 and perform CMP planarization; After electroplating, the laminated structure is heated to soften the bonding adhesive, and the auxiliary substrate 400 is slowly peeled off in a direction parallel to the substrate surface. Then, the residual adhesive layer is cleaned and removed. Finally, planarization was completed using chemical mechanical polishing equipment. After polishing, the substrate surface was rinsed with deionized water to thoroughly remove residual polishing liquid and abrasive debris. It was then dried with high-purity nitrogen gas to obtain a glass substrate 100 with a smooth surface and densely filled vias.

[0043] The glass substrate 100 prepared by the above embodiments has a metal filling layer 300 in the through hole 110 that is tightly bonded to the hole wall through the transition metal layer 200, without void defects, with high interface bonding strength and stable vertical interconnect performance. It can meet the manufacturing needs of various high-precision electronic devices such as 5G communication devices, three-dimensional system-in-package, and MEMS sensors. Moreover, it has a wide process window and strong mass production stability. Compared with the traditional physical vapor deposition combined with electroplating process, it can significantly reduce equipment investment and operation and maintenance costs.

[0044] In addition, the CMP flattening step in this article can be set according to actual needs. For ease of understanding, an example of a feasible solution of the present invention is provided. CMP planarization includes the following steps: First, rough polishing is performed until a copper layer of 2-3 μm remains on the glass surface to prevent the glass surface from being directly impacted by polishing; then, fine polishing is performed to continue removing the remaining copper layer until the glass substrate surface is completely exposed; next, over-polishing is performed to finish the process, using a very short controlled over-polishing process with abrasive-free or low-abrasive polishing fluid to control the copper depression at the via opening to within a range of less than 70-100 nm, ensuring that the surface roughness (Ra) after polishing is less than 0.5 nm and the height difference between the copper surface and the glass surface is less than 5 nm; finally, post-CMP cleaning is performed, which includes the following steps in sequence: megasonic cleaning, PVA brush scrubbing, and SC1 or dilute acid chemical cleaning. Megasonic cleaning is used to physically remove nanoscale abrasive particles, PVA brush scrubbing is used to mechanically remove loose particles on the surface, and SC1 or dilute acid chemical cleaning is used to dissolve residual copper ions and remove organic contaminants, thoroughly removing residual copper ions and polishing abrasive particles, and avoiding copper shavings remaining on the glass surface.

[0045] The present invention also proposes a glass substrate, comprising: a glass substrate body, a transition metal layer 200, and a metal filling layer 300. A through-hole 110 is formed on the glass substrate body. The transition metal layer 200 is disposed on the surface of the hole wall of the through-hole 110, and the transition metal layer 200 is in close contact with the hole wall of the through-hole 110. The metal filling layer 300 is disposed within the through-hole 110 and located on the inner peripheral side of the transition metal layer 200, and the metal filling layer 300 is bonded to the inner peripheral surface of the transition metal layer 200. The transition metal layer 200 and the metal filling layer 300 fill the internal space of the through-hole 110. This glass substrate can be prepared by the glass through-hole filling method described above.

[0046] See Figures 1 to 4 As shown, in some embodiments, the metal filler layer 300 consists of a flash-plated copper layer and an electroplated copper layer located on the inner periphery of the flash-plated copper layer, the flash-plated copper layer covering the inner periphery of the transition metal layer 200. This structure can be prepared by Example 1 above.

[0047] See Figures 5 to 9 As shown, in some embodiments, the metal filler layer 300 is a single electroplated copper layer. This structure can be prepared by Example 2 above.

[0048] It should be noted that the terminology used above is for describing specific embodiments only and is not intended to limit the exemplary embodiments of the present invention. When the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. The order of execution of actions, steps, etc., of the methods shown in the specification can be implemented in any order unless a specific express order is specified, and as long as the output of the preceding process is not used in the subsequent process. Similar sequential terms used for ease of description do not imply that such an order must be followed.

[0049] Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for filling glass vias based on a transition metal layer, characterized in that, Includes the following steps: Provide a glass substrate with through holes; The through holes are cleaned and the hole walls are activated. A transition metal layer is prepared on the inner wall of the through hole; The through holes are filled by electroplating; The glass substrate is planarized.

2. The glass through-hole filling method according to claim 1, characterized in that, A transition metal layer is prepared on the inner wall of the through hole, including: The reaction is carried out in a liquid phase environment at 40~50℃ for 2~3 hours to form a transition metal layer on the inner wall of the through hole; It is then immersed in a solution containing palladium catalyst for activation treatment, soaking at room temperature for 3-5 minutes.

3. The glass through-hole filling method according to claim 2, characterized in that, After the transition metal layer is prepared, the surface of the transition metal layer is first flash plated, and then the through holes are electroplated and filled using a process combining bridging electroplating and hole-filling electroplating.

4. The glass through-hole filling method according to claim 3, characterized in that, The flash plating is a horizontal flash plating, using a DC power supply with a current density of 1~2A / dm² and a plating time of 10~15min; The process parameters for the bridging electroplating stage are as follows: a pulse power supply is used, the forward current density is 0.1~0.3A / dm², the ratio of forward energizing time to reverse energizing time is 1:3~1:5, and the electroplating time is 3~4h. The process parameters for the hole-filling electroplating stage are as follows: a DC power supply is used, the current density is 1~2A / dm², and the electroplating time is 70~90min.

5. The glass through-hole filling method according to claim 1, characterized in that, A transition metal layer is prepared on the inner wall of the through hole, including: An auxiliary substrate is bonded to the side of the glass substrate opposite to the through-hole opening; The through-holes are filled using a supercritical carbon dioxide-assisted chemical plating process, in which organometallic compounds are dissolved in supercritical carbon dioxide to form a transition metal layer.

6. The glass through-hole filling method according to claim 5, characterized in that, Electroplating filling of the through holes includes: The through holes are filled by electroplating using a DC electroplating process. After the holes are filled, the auxiliary substrate is removed.

7. The glass through-hole filling method according to claim 4, characterized in that, The current density for the DC hole-filling electroplating is 1~2A / dm², and the electroplating time is 70~90min.

8. The glass through-hole filling method according to claim 1, characterized in that, The pore wall activation treatment is plasma treatment, and the process parameters are as follows: a box-type plasma device is used, the vacuum degree is 0.5~0.9Pa, an argon-oxygen mixture is introduced, the power is 1~3kW, and the treatment time is 1~3min.

9. The glass through-hole filling method according to any one of claims 1 to 8, characterized in that, The diameter of the through hole is 20~50μm, and the aspect ratio is ≥10:

1.

10. The glass through-hole filling method according to claim 2 or 5, characterized in that, The thickness of the transition metal layer is 300~500nm.

11. A glass substrate, characterized in that, include: A glass substrate body, wherein through holes are formed on the glass substrate body; A transition metal layer is disposed on the surface of the hole wall of the through hole, and the transition metal layer is in close contact with the hole wall of the through hole; A metal filler layer is disposed within the through hole and located on the inner peripheral side of the transition metal layer, and the metal filler layer is bonded to the inner peripheral surface of the transition metal layer; The transition metal layer and the metal filling layer fill the internal space of the through hole.

12. The glass substrate according to claim 11, characterized in that, The metal filler layer consists of a flash-plated copper layer and an electroplated copper layer located on the inner periphery of the flash-plated copper layer, the flash-plated copper layer covering the inner periphery of the transition metal layer.

13. The glass substrate according to claim 11, characterized in that, The metal filler layer is a single electroplated copper layer.

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