Method for depositing copper thin-film in through glass via using atomic sputtering epitaxy

Abstract

The present invention relates to electronic packaging and semiconductor process technology using through glass via (TGV) technology, and relates to a method for improving electrical characteristics through more reliable copper (Cu) thin-film deposition. The method for depositing a copper thin-film in a TGV using atomic layer sputtering epitaxy (ASE) according to the present invention is characterized in that a copper thin film is uniformly deposited inside and on the surface of a through glass via (TGV) by using an atomic layer sputtering epitaxy (ASE) process, wherein the copper thin film is deposited such that the electrical resistance of the upper and lower portions of the TGV is 0.1 or less.

Description

Method for depositing copper thin films in TGV using atomic layer sputtering epitaxy

[0001] The present invention relates to electronic packaging and semiconductor process technology utilizing TGV (Through Glass Via) technology, and to a method for improving electrical characteristics through the deposition of a more reliable copper (Cu) thin film.

[0002]

[0003] Through Glass Via (TGV) technology plays a significant role in the semiconductor and electronic packaging industries, and is receiving particular attention in RF and 3D integrated circuit (3D IC) applications. TGV is a technology that provides electrical connections between upper and lower circuits by forming tiny conductive vias that penetrate a glass substrate. Glass possesses low dielectric loss and high insulation resistance, making it more advantageous for RF signal transmission than conventional silicon (Si)-based substrates; it is also utilized in MEMS (Micro-Electro-Mechanical Systems), opto-electronic systems, and high-speed data transmission applications. Due to these characteristics, TGV technology has established itself as an essential element in next-generation semiconductors and high-performance packaging solutions.

[0004] However, existing TGV technology faces several major technical challenges. First, because glass is inherently an insulator, it is difficult to uniformly deposit conductive materials into vias formed within it. In particular, due to the low adhesion between glass and metal, process optimization is required to secure reliable conductive paths. Conventional processes have used methods that involve forming additional adhesion layers, such as titanium (Ti) or chromium (Cr), for copper (Cu) deposition; however, this approach has the disadvantages of being complex and increasing manufacturing costs. Furthermore, it is difficult to uniformly deposit metal on the inner walls of the TGV, and there is a high likelihood that electrical characteristics will degrade due to non-uniform coating.

[0005] To solve these problems, the present invention proposes a technology for depositing a uniform copper thin film on the interior and surface of a TGV by applying an Atomic Sputtering Epitaxy (ASE) process. By utilizing the ASE process, copper can be directly deposited without a conventional adhesive layer, and a uniform conductive coating can be formed across the entire inner wall of the TGV. Furthermore, by controlling the surface roughness of the copper thin film to the nm level, electrical reliability can be ensured, and by lowering the resistance value, optimal performance can be provided in semiconductor packaging and RF applications. It is expected that the technology of the present invention will overcome the limitations of existing TGV processes and enable more reliable electrical connections in next-generation electronic packaging and semiconductor integrated circuits.

[0006]

[0007] The present invention was devised to solve the above problems, and the objective of the present invention is to apply Atomic Sputtering Epitaxy (ASE) technology to secure the reliability of the bond between glass and metal and to improve electrical performance through uniform thin film deposition.

[0008] The technical problems that the invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which the invention belongs from the description below.

[0009]

[0010] A method for depositing a copper thin film in a TGV using atomic layer sputtering epitaxy according to the present invention is

[0011] A copper thin film is uniformly deposited on the interior and surface of a TGV (Through Glass Via) using an Atomic Layer Sputtering Epitaxy (ASE) process,

[0012] The above TGV is characterized by depositing a copper thin film so that the upper and lower electrical resistances are 0.1 Ω or less.

[0013] In addition, the present invention is characterized by depositing a copper thin film over the entire inner wall of the TGV such that the thickness variation is ±5 nm or less.

[0014] In addition, the present invention is characterized by forming a copper thin film such that the bonding strength between glass and copper is 50 MPa or more.

[0015] In addition, the present invention is characterized by forming a copper thin film formed through the atomic layer sputtering epitaxy process such that the average surface roughness (RMS roughness) is in the range of 4.5 nm or less.

[0016] In addition, the present invention is characterized in that the thickness of the copper thin film formed through the atomic layer sputtering epitaxy process is 2,000 nm or less.

[0017]

[0018] By means of the above-mentioned solution to the problem, the present invention can effectively solve the problems of the existing TGV process, such as insufficient reliability of bonding between metal and glass, non-uniformity of inner wall coating, and degradation of electrical characteristics.

[0019] In addition, by applying the ASE process, the present invention allows for the direct deposition of copper without an adhesive layer, thereby simplifying the process and reducing manufacturing costs.

[0020] In addition, the present invention can secure high electrical reliability and low resistance values ​​by precisely controlling surface roughness at the nanometer (nm) level, and provides stable conductivity between the upper and lower electrodes.

[0021] In addition, the present invention can be utilized as a process suitable for mass production and minimizing signal loss in next-generation semiconductor and electronic packaging fields such as radio frequency (RF), high-density integrated circuits (HDI), and 3D stacked packaging (3D IC).

[0022]

[0023] Figure 1 is a flowchart showing a glass semiconductor process including a copper thin film deposition method in a TGV using atomic layer sputtering epitaxy according to the present invention.

[0024] Figure 2 is a flowchart showing a conventional glass semiconductor process.

[0025] Figure 3 is an image of Cu / TGV / Cu (right) with copper deposited on both sides of TGV (left) according to an embodiment of the present invention.

[0026] Figure 4 is an experimental photograph (right) confirming that the two sides are connected as conductors by measuring conductivity after depositing a copper thin film on both sides of a TGV (Cu / Glass, left) according to an embodiment of the present invention.

[0027] Figure 5 is an image observed with an Optical Microscope after copper was deposited on both sides of a TGV (left) according to an embodiment of the present invention.

[0028] Figure 6 is the result of confirming the thickness of a copper thin film (Cu / patterned Glass, left) deposited on one side according to an embodiment of the present invention using an atomic forced microscope (AFM).

[0029] Figure 7 shows the result of confirming the surface roughness of a copper thin film (left) deposited on a TGV according to an embodiment of the present invention using an atomic forced microscope (AFM).

[0030] Figure 8 is the result of observing with an SEM at different measurement magnifications after depositing a copper thin film on a TGV according to an embodiment of the present invention.

[0031] Figure 9 is the result of SEM measurement to confirm whether copper was coated on the TGV in cross-section according to an embodiment of the present invention.

[0032] FIG. 10 is an example of observing a cross-section by cutting a sample as shown in the left (a) and right (b) figures to view the inside of a hole according to an embodiment of the present invention.

[0033] Figure 11 is the result of observing with an SEM with different ratios of samples cut as shown in the left (a) figure of Figure 10 according to an embodiment of the present invention.

[0034] Figure 12 is the SEM measurement result of a sample cut as shown in the right (b) figure of Figure 10 according to an embodiment of the present invention.

[0035] Figure 13 is the result of EDS measurement of a sample cut as shown in the left (a) figure of Figure 10 according to an embodiment of the present invention.

[0036] Figure 14 shows the EDS measurement results of a sample cut as shown in the left (a) figure of Figure 10 according to an embodiment of the present invention, categorized by component distribution.

[0037] Figure 15 is the result of observing the inside of a via hole with an SEM by varying the ratio of the sample cut as shown in the right (b) figure of Figure 10 according to an embodiment of the present invention.

[0038] FIG. 16 is a figure showing when Cu is deposited on one side (a) and when it is deposited on both sides (b) of a TGV according to an embodiment of the present invention.

[0039] FIG. 17 is a photograph of a TGV with Cu deposited on both sides but a non-deposited portion in the middle to see if current flows through copper deposited in via holes according to an embodiment of the present invention (a) and a photograph of a sheet resistance measurement (b).

[0040] FIG. 18 is the sheet resistance measurement values ​​of ab, bc, cd, and da of FIG. 17 according to an embodiment of the present invention.

[0041] FIG. 19 is a sheet resistance measurement value of FIG. 17 according to an embodiment of the present invention.

[0042] Figure 20 is the result of observing the interior of a TGV where Cu is not deposited according to an embodiment of the present invention using SEM at different ratios.

[0043] Figure 21 is the result of observing the interior of a TGV without Cu deposition according to a comparative example of the present invention using SEM.

[0044] Figure 22 is the result of observing the inside of a TGV hole in which Cu is deposited on both sides according to an embodiment of the present invention using SEM.

[0045] FIG. 23 is an SEM image comparing the inside of a TGV (a) with no Cu deposited and a TGV (b) with copper deposited on both sides, magnified 10,000 times according to an embodiment of the present invention.

[0046] Figure 24 is the result of observing surface roughness by thickness using an AFM according to an embodiment of the present invention.

[0047]

[0048] The terms used in this specification will be briefly explained, and the invention will be described in detail.

[0049] The terms used in this invention have been selected based on currently widely used general terms while considering their functions within the invention; however, these terms may vary depending on the intent of those skilled in the art, case law, the emergence of new technologies, etc. Therefore, the terms used in this invention should be defined not merely by their names, but based on their meanings and the overall context of the invention.

[0050] When a part of a specification is described as “comprising” a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0051] Embodiments of the present invention are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0052] Specific details regarding the problem to be solved by the present invention, the means for solving the problem, and the effects of the invention are included in the embodiments and drawings described below. The advantages and features of the present invention, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the accompanying drawings.

[0053] Hereinafter, the present invention will be described in more detail with reference to the attached drawings.

[0054]

[0055] The present invention relates to a method for uniformly depositing a copper thin film on the inside and surface of a TGV (Through Glass Via) using an atomic layer sputtering epitaxy (hereinafter ASE) process.

[0056] As shown in Figure 1, in the conventional TGV process, it was common to deposit copper (Cu) using an adhesive layer such as Ti or Cr, but this method causes problems such as a complex process and increased manufacturing costs. In addition, even with an adhesive layer, it is difficult to form a uniform copper thin film over the entire inner wall of the TGV, which can result in incomplete electrical connectivity or high resistance values.

[0057] In contrast, the present invention enables the direct deposition of copper without an adhesive layer by applying an ASE process. The ASE process utilizes highly controlled sputtering technology to enable atomic-level deposition, thereby allowing a copper thin film to be formed with a uniform thickness on the inner wall and surface of the TGV.

[0058] Unlike conventional methods, the ASE process of the present invention simplifies the process by allowing copper to be directly deposited without an additional adhesive layer. A lower resistance value can be secured by precisely controlling the thickness and surface characteristics of the copper thin film. Electrical connectivity is improved by forming a uniform conductive path across the entire inner wall of the TGV compared to conventional electroplating methods.

[0059] More specifically, as shown in Figure 2, a Ti adhesive layer (Barrier & Seed Layer) for copper (Cu) deposition is required in the conventional glass semiconductor process, and the overall process proceeds as follows.

[0060] Glass production involves manufacturing glass substrates and adjusting specifications based on the coefficient of thermal expansion.

[0061] Bare glass processing processes glass substrates to meet desired specifications.

[0062] Hole processing forms a TGV (Through Glass Via) structure using laser processing or wet / dry etching.

[0063] The barrier and seed layer formation step usually requires preliminary work to form a seed layer for Cu deposition after depositing a Ti layer. Although the Ti layer improves the adhesion of the copper thin film, it requires additional process steps and increases manufacturing costs.

[0064] The wiring process involves patterning following lithography and development, followed by an electroplating process. This process can be performed repeatedly.

[0065] The polishing process ultimately performs surface polishing to form a uniform surface.

[0066] The present invention provides a method for directly depositing Cu without a Ti adhesive layer by applying an ASE (Atomic Sputtering Epitaxy) process, and as shown in FIG. 1, there is a difference in the formation of the barrier and seed layer.

[0067] In conventional processes, a seed layer for Cu deposition is required after depositing a Ti layer; however, in the present invention, Cu can be directly deposited without a Ti layer by utilizing the ASE process. In other words, since Ti deposition is not required, the process is simplified and costs can be reduced.

[0068] In addition, the wiring process proceeds with photolithography and patterning in the same way as the existing process, and copper plating is possible. Since the copper thin film deposited through the ASE process maintains uniformity inside the TGV, high electrical connectivity can be secured without forming an additional adhesive layer.

[0069]

[0070] The present invention relates to a technology for uniformly depositing a copper thin film inside and on the surface of a glass-through-via (TGV) using an Atomic Sputtering Epitaxy (ASE) process. In particular, the present invention aims to secure excellent electrical characteristics in the fields of high-speed data transmission and RF packaging by depositing the film so that the electrical resistance of the upper and lower parts of the TGV is 0.1 Ω or less (based on a glass thickness of 500 µm and a hole diameter of 95 µm, with an aspect ratio of the depth to the diameter of the via hole being 1:5).

[0071] Conventional copper deposition methods (e.g., electroplating or PVD) can lead to thickness imbalance and increased resistance on the inner walls of TGVs. However, the ASE process applied in the present invention can control deposition at the atomic layer level, which has the advantage of forming a more uniform copper thin film and securing a low resistance value.

[0072] By applying the ASE-based deposition method of the present invention, a copper thin film is uniformly formed along the inner wall of the TGV, and the upper and lower parts of the TGV are smoothly connected to maintain a low resistance value. Through this, compared to existing technologies, power loss is reduced, signal transmission speed is faster, and stable performance can be provided in semiconductor packaging and high-frequency applications.

[0073]

[0074] In addition, the present invention includes a method for forming a uniform copper thin film across the entire inner wall of a TGV. In conventional copper deposition methods (e.g., electroplating, PVD), significant thickness variations occur between the upper and lower parts of the TGV or in specific parts of the inner wall, making it difficult to secure a uniform conductive path.

[0075] Since the ASE process of the present invention enables precise deposition control at the atomic layer level, the thickness variation of the copper thin film across the entire inner wall of the TGV can be maintained at ±5 nm or less. Through this, the uniformity of electrical connections is improved, and the variation in resistance values ​​is reduced, thereby improving overall reliability.

[0076] In addition, uniformity can be ensured by measuring thickness variations through Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) analysis. Through this, it can be verified that the copper thin film with the ASE process applied is precisely formed inside the TGV structure, and high reliability can be maintained even in high-speed signal transmission applications.

[0077] In conventional methods, thickness variations of copper thin films often exceeded ±10 nm depending on the position of the TGV inner wall. The electric field is non-uniformly distributed depending on the shape of the TGV inner wall; in particular, the current density is high at the top of the TGV and low at the bottom, making uniform deposition difficult. Additionally, due to the strong directional nature of PVD deposition, the deposition rate decreases as it moves toward the bottom of the TGV. Consequently, there is a problem in that it is difficult to secure a uniform thickness throughout the entire interior of the TGV.

[0078] In contrast, the ASE method of the present invention is optimized to deposit copper atoms with high uniformity by controlling plasma energy. That is, by applying RF plasma control technology that maintains a constant deposition rate, it is possible to control the thickness variation across the entire inner wall of the TGV to be ±5 nm or less. It was confirmed that the same thickness is maintained across the entire inner wall even when the depth of the TGV is at the level of 400 to 700 μm.

[0079] Through the formation of such a uniform thin film, the current flow through the TGV is maintained constant, and a highly reliable conductive path can be provided.

[0080]

[0081] In addition, problems such as delamination occurring due to low bonding strength between copper and glass are frequently reported in the existing TGV process. In particular, if the adhesion is weak, reliability may be compromised in high temperature and high humidity environments.

[0082] In the present invention, the ASE process is utilized to enable the direct deposition of a copper thin film without an additional adhesive layer (Ti, Cr, etc.). Through the high deposition energy of the ASE process, copper atoms can be strongly bonded to the glass surface, and the bonding strength can be maintained at 50 MPa or higher.

[0083] Through this, while conventional methods required the use of Ti or Cr as an adhesive layer, the ASE method enables the formation of copper thin films without such layers by controlling plasma energy to allow copper atoms to bond directly with the glass surface. Plasma activation is performed on the glass surface early in the ASE process to induce stronger bonding of copper atoms. This process ensures a bonding strength of over 50 MPa between the glass and copper. Consequently, the reliability of the TGV can be maintained even in high-temperature and high-humidity environments, making it suitable for high-performance semiconductor packaging.

[0084]

[0085] In addition, copper thin films formed by conventional electroplating or PVD processes have relatively high surface roughness (RMS roughness), which may lead to degradation of electrical properties and signal transmission loss.

[0086] By applying the ASE process of the present invention, the surface roughness of the copper thin film can be precisely controlled, and the RMS roughness can be maintained within a range of 4.5 nm or less. More preferably, it can be maintained within a range of 3.0 to 4.5 nm.

[0087] In the conventional PVD method, roughness of 5 to 10 nm or more can be formed, which increases the likelihood of loss during RF signal transmission. In the ASE method, stable surface roughness within the range of 3.0 to 4.5 nm can be provided by precisely controlling the deposition rate.

[0088] Low surface roughness reduces electrical contact resistance and contributes to minimizing reflection losses during high-speed signal transmission. Additionally, the ASE process enables the formation of uniform thin films, which can provide excellent signal transmission characteristics for RF and high-frequency applications.

[0089]

[0090] In addition, the present invention aims to maintain the thickness of the copper thin film deposited on the inner wall and surface of the TGV at 1,100 nm or more using the ASE process.

[0091] In conventional methods, there was a possibility that electrical connectivity would be degraded due to non-uniform thickness or becoming too thin. The ASE-based copper deposition method of the present invention is designed to ensure sufficient conductivity while maintaining a uniform thickness.

[0092] By applying the ASE process of the present invention, the thickness of the copper thin film can be maintained at 1,100 nm or more, thereby improving electrical connectivity. If sufficient thickness is not secured in the inner wall of the TGV, reliability may be reduced due to uneven current density during signal transmission, and maintaining the copper thin film thickness at 1,100 nm or more increases the current carrying capacity, thereby improving signal transmission characteristics. The ASE method allows for precise control of thickness, making it possible to secure a uniform conduction path compared to conventional methods.

[0093] Through this, the copper thin film in the TGV can form a highly reliable conductive path and can also exhibit excellent performance in high-speed data transmission and RF signal transmission.

[0094]

[0095] The ASE-based copper thin film deposition process of the present invention is a method of depositing copper atoms in atomic layer units under a highly controlled plasma state. During the deposition process, the following process variables are optimized.

[0096] ① Process temperature and initial pressure

[0097] The temperature of the deposition environment is controlled in the range of 170°C, and the initial vacuum is 1.5×10⁻⁶ -6 The pressure is below Torr, and deposition is carried out in an Ar atmosphere at a pressure of 5.4 × 10⁻⁶. - ³ It must be maintained within the Torr range.

[0098]

[0099] ② Plasma pressure control

[0100] The plasma process is carried out in an Ar atmosphere at a pressure of 5.4 × 10⁻⁶ - ³ Stabilize the process atmosphere by maintaining it at a constant Torr.

[0101] When deposited under these conditions, copper is uniformly formed over the entire inner wall of the TGV.

[0102]

[0103] In the electroplating method, copper is deposited through a chemical reaction within an electrolyte solution, and thickness unevenness may occur due to differences in current density on the inner wall of the TGV. Since the ASE method performs deposition at the atomic level, uniform deposition is possible even inside the TGV, and the possibility of impurity incorporation is low. Through the application of this optimized ASE process, the electrical resistance of the top and bottom of the TGV can be maintained at 0.1 Ω or less, and uniform conductivity suitable for high-speed signal transmission is ensured.

[0104]

[0105] Hereinafter, the present invention will be explained in more detail through comparative examples and embodiments prepared by conventional methods and experimental examples. The purpose, features, and advantages of the present invention will be easily understood through the following embodiments. The present invention is not limited to the embodiments described herein and may be embodied in other forms. The embodiments introduced herein are provided to ensure that the concept of the present invention is sufficiently conveyed to those skilled in the art to which the present invention pertains. Therefore, the present invention should not be limited by the following embodiments.

[0106]

[0107] Example 1: Copper thin film deposition in TGV using the ASE process

[0108] In this embodiment, a method for depositing a uniform copper thin film on the inner wall and surface of the TGV using the Atomic Sputtering Epitaxy (ASE) process was applied and is shown in Fig. 3. Through this, the uniform thickness formation and electrical characteristics of the copper thin film were evaluated in the experimental examples below.

[0109] - Substrate (Materials): Asahi Glass (thickness 500 μm)

[0110] - TGV Formation Method: TGV processing using laser drilling

[0111] - TGV Hole Size: Approx. 94 μm

[0112] - TGV Hole Depth: 500 μm

[0113] - Copper thin film deposition method: ASE process applied

[0114] - Deposition Conditions:

[0115] - Plasma gas: Ar

[0116] - Process temperature: 170°C

[0117] - Deposition pressure: 5.4×10⁻⁶ - ³ Torr

[0118]

[0119] Experimental Example 1: Evaluation of Electrical Characteristics

[0120] As shown in Figure 4, in Experimental Example 1, conductivity was measured after depositing a copper thin film on both sides of the TGV to confirm that both sides were connected as conductors.

[0121] The experimental conditions are as follows.

[0122] - Application of 4-Probe Resistance Measurement Method

[0123] - Measurement of electrical resistance

[0124] The electrical resistance was evaluated by connecting the upper and lower parts of the TGV.

[0125] It was confirmed that the resistance value decreased by more than 30% when the ASE process was applied compared to the existing electroplating method.

[0126]

[0127] Experimental Example 2: Optical Microscope Analysis

[0128] After forming a Through Glass Via (TGV) on a glass substrate (Asahi Glass, thickness 500 μm) using laser drilling, a copper thin film was deposited on the inner wall of the TGV by applying an Atomic Sputtering Epitaxy (ASE) process. After applying the ASE process, the diameter and shape of the TGV were analyzed using an Optical Microscope, and the effect of the ASE process on the uniformity and size retention of the TGV pattern was evaluated.

[0129] As shown in Figure 5, optical microscope analysis confirmed that the diameter of the TGV (94.88 μm, 94.26 μm) was maintained even after the application of the ASE process, and that the copper thin film was uniformly formed over the entire inner wall. In addition, it was proven that the TGV pattern was maintained without deformation through the ASE process, and that the reliability of the conductive path was improved by ensuring the uniformity of the copper thin film deposition.

[0130]

[0131] Experimental Example 3: Measurement of Copper Thin Film Deposition Thickness

[0132] A copper (Cu) thin film was deposited on a glass substrate using the Atomic Sputtering Epitaxy (ASE) process, and the thickness of the deposited copper film was measured using Atomic Force Microscopy (AFM). The measurement targets were samples with a Cu / Al₂O₃ structure, and the uniformity of the deposition via the ASE process was evaluated by analyzing the variation in copper film thickness on one side.

[0133] As shown in Figure 6, AFM analysis results showed that the average thickness of the copper thin film deposited via the ASE process was measured to be 1,133 nm, and it was confirmed that a uniform deposition of approximately 1,130 nm was achieved on one side. This demonstrates that the ASE process can secure sufficient thickness while maintaining high uniformity compared to conventional deposition methods, and suggests that it can provide reliable electrical characteristics through the formation of uniform conductive paths.

[0134]

[0135] Experimental Example 4: Analysis of Surface Roughness (RMS Roughness) of Copper Thin Film

[0136] After depositing copper thin films on the inner wall and surface of the TGV (Through Glass Via) using the ASE (Atomic Sputtering Epitaxy) process, the surface roughness (RMS roughness) of the thin films was measured using AFM (Atomic Force Microscopy). The analysis was performed on copper thin films deposited at specific locations on the inner wall of the TGV, and the measured data was collected within a 10 μm² area.

[0137] As shown in Figure 7, AFM analysis results showed that the RMS roughness of the copper thin film applied using the ASE process was measured to be 3.288 nm and 3.424 nm, which means that it provides a more uniform surface compared to the conventional electroplating method. This low surface roughness can contribute to a reduction in electrical contact resistance and an improvement in RF signal transmission characteristics, and it has been proven that the ASE process enables the formation of a uniform thin film on the inner wall of the TGV.

[0138] In addition, copper thin films of different thicknesses (20 nm (b), 100 nm (c), 1,100 nm (d)) were deposited on a glass substrate (Asahi Glass) using the Atomic Sputtering Epitaxy (ASE) process, and then Atomic Force Microscopy (AFM) analysis was performed. For each sample, the Root Mean Square (RMS) roughness value was measured to quantitatively evaluate the surface roughness, and the change in roughness according to the change in copper thin film thickness was analyzed. Through this, it was confirmed how uniformly the copper thin films applied by the ASE process are deposited as the thickness increases.

[0139] As shown in Figure 24, AFM analysis revealed that the RMS roughness of the bare glass substrate was 0.692 nm. As the copper film thickness increased to 20 nm and 100 nm, the values ​​increased slightly to 1.102 nm and 1.134 nm, respectively, but still maintained a low level of surface roughness. On the other hand, for a copper film with a thickness of 1,100 nm, the RMS roughness value increased to 4.567 nm, confirming that surface roughness increases with increasing film thickness. This suggests that while the ASE process enables very uniform deposition for thin copper films, there is a possibility that surface roughness may increase due to grain growth as the thickness increases. Through these results, it was confirmed that while copper films produced by the ASE process maintain excellent surface uniformity, deposition conditions need to be optimized beyond a certain thickness.

[0140]

[0141] Experimental Example 5: SEM (Scanning Electron Microscopy) Analysis

[0142] After depositing a copper thin film on the inner wall and surface of a Through Glass Via (TGV) using the Atomic Sputtering Epitaxy (ASE) process, Scanning Electron Microscopy (SEM) analysis was performed. The top and cross-sections of the TGV structure were observed at various magnifications (x50, x100, x500) to evaluate the uniformity, thickness variation, and deposition state of the copper thin film formed through the ASE process.

[0143] As shown in Figure 8, SEM analysis confirmed that a uniform copper thin film was formed across the entire inner wall of the TGV through the ASE process, and that a consistent conductive path was secured without thickness variation. In particular, cross-sectional images observed at x500 magnification visually demonstrated that the copper thin film on the inner wall of the TGV was uniformly deposited, confirming that the ASE process provides superior thin film uniformity compared to conventional methods.

[0144]

[0145] Experimental Example 6: Confirmation of Cross-sectional Deposition of Copper Thin Film Inside TGV

[0146] After depositing a copper (Cu) thin film on the inner wall of a TGV (Through Glass Via) using the Atomic Sputtering Epitaxy (ASE) process, Scanning Electron Microscopy (SEM) analysis was performed. In the experiment, the cross-section of the TGV was observed at various magnifications (×157, ×500) to verify whether the copper thin film was uniformly deposited across the entire inner wall through the ASE process, and the coating thickness and shape at specific points on the cross-section were measured.

[0147] As shown in Figure 9, SEM analysis confirmed that the copper thin film deposited via the ASE process was uniformly coated across the entire inner wall of the TGV and formed with a uniform thickness even in specific cross-sections. The measured cross-sectional dimensions (92.22 μm, 200.9 μm) and the uniformity of the analyzed copper thin film demonstrated that the ASE process provides higher coating precision compared to conventional methods and suggests that it can improve the reliability of conductive paths within the TGV.

[0148]

[0149] Experimental Example 7: Cross-sectional Analysis of Copper Thin Film in TGV

[0150] As shown in Fig. 10, after depositing a copper thin film on the inner wall of a TGV (Through Glass Via) using the Atomic Sputtering Epitaxy (ASE) process, the sample was cut at a specific angle to evaluate the coating uniformity of the deposited copper thin film. The cut cross-section was analyzed using Scanning Electron Microscopy (SEM) to confirm whether the copper thin film was uniformly deposited over the entire inner wall of the TGV, and to evaluate the thickness variation and deposition status.

[0151] After depositing a copper thin film on the inner wall of a TGV (Through Glass Via) using the Atomic Sputtering Epitaxy (ASE) process, Scanning Electron Microscopy (SEM) observation was performed to analyze the structural characteristics and bonding morphology of the deposited thin film. As shown in Figure 11, the sample was cut at a specific angle to expose the cross-section, and SEM analysis was performed at various magnifications (×100, ×500, ×1000) to evaluate the uniformity of the copper thin film, the formation of conductive paths, and the bonding state within the cross-section.

[0152] As shown in Figure 11, SEM analysis confirmed that the copper thin film deposited via the ASE process was uniformly formed across the entire inner wall of the TGV, and that a conductive path was clearly secured. Furthermore, cross-sectional observation revealed evidence suggesting that the copper thin film formed a Cu / TGV / Cu structure traversing the TGV, rather than simply coating the inner wall. The fragments of the cut sample generated during the experiment were produced during measurements for analysis, proving that the copper thin film formed via the ASE process possessed excellent bonding reliability within the TGV structure.

[0153] In addition, as shown in Fig. 12, the cross-section was photographed at high magnification (×1000) to clearly identify the interface between the copper thin film and the glass substrate, and the thin film thickness was precisely measured. SEM analysis confirmed that the copper thin film deposited via the ASE process was uniformly formed with a thickness of 1.196 μm. It was demonstrated that the copper thin film is stably bonded to the glass substrate and that the thickness variation is minimized, thereby providing a uniform conduction path. These results suggest that the ASE process guarantees superior thin film uniformity compared to conventional methods and can provide high reliability in TGV-based electronic packaging technology.

[0154]

[0155] Experimental Example 8: EDS (Energy Dispersive Spectroscopy) Analysis

[0156] After depositing a copper thin film on the inner wall of a Through Glass Via (TGV) using the Atomic Sputtering Epitaxy (ASE) process, the elemental composition was evaluated by performing Energy Dispersive Spectroscopy (EDS) analysis. The elemental distribution inside the TGV was visually confirmed through EDS analysis combined with Scanning Electron Microscopy (SEM), and the elemental composition and relative distribution of copper (Cu), silicon (Si), and oxygen (O) were compared. The areas marked in blue in the CuK image represent the copper thin film deposited on the inner wall of the TGV, thereby evaluating the uniformity of the copper deposition.

[0157] As shown in Fig. 13(a), EDS analysis confirmed that copper was uniformly deposited on the inner wall of the TGV through the ASE process and maintained a consistent distribution even within the hole. As shown in Fig. 13(b), the copper (Cu) signal was clearly detected through component analysis, proving that the ASE process is a deposition process that provides higher uniformity compared to conventional methods. Additionally, as shown in Fig. 14, the area marked in blue in the CuK image clearly showed the copper thin film formed inside the TGV, suggesting that copper deposition using the ASE process was successfully achieved.

[0158]

[0159] ElementWt %At %OK48.8465.21SiK41.4331.51CuK09.7403.27MatrixCorrectionZAF

[0160]

[0161] Experimental Example 9: Uniformity and Surface Analysis

[0162] After depositing a copper thin film on the inner wall of a Through Glass Via (TGV) using the Atomic Sputtering Epitaxy (ASE) process, the sample tilted at 45 degrees in Fig. 10(b) was analyzed using Scanning Electron Microscopy (SEM). SEM images were acquired at various magnifications to evaluate whether the copper thin film was uniformly deposited into the interior of the TGV and how smoothly the surface was formed. In addition, it was confirmed how homogeneously the copper thin film was formed on the glass surface.

[0163] As shown in Fig. 15, SEM analysis confirmed that the copper thin film was smoothly deposited inside the TGV via the ASE process, and that a highly homogeneous coating was achieved on the glass surface. In particular, high-magnification analysis demonstrated that the copper thin film was smoothly deposited not only on the substrate surface but also inside the TGV, proving that the reliability of the conductive path was improved through the formation of a homogeneous thin film. These results demonstrate that the ASE process is effective in forming more precise and homogeneous thin films compared to conventional methods.

[0164]

[0165] Experimental Example 10: Comparison of Sheet Resistance and Resistivity

[0166] After depositing a copper thin film on the inner wall of a Through Glass Via (TGV) using the Atomic Sputtering Epitaxy (ASE) process, sheet resistance and resistivity measurement experiments were performed to compare the electrical characteristics of one-sided deposition (a) and two-sided deposition (b), as shown in Fig. 16. The conductive path inside the TGV was analyzed using a 4-point probe measurement method, and the resistance across both ends was measured and calculated using the parallel resistance method.

[0167]

[0168] Experimental Conditions Surface Resistance Value (Ω / sq) ASE Process Applied (Copper 1,100 nm Deposition) 0.0864 Ω / sq Conventional Electroplating Method (Copper 1,100 nm Deposition) 0.12 Ω / sq

[0169]

[0170] Measurement results confirmed that the sheet resistance of the single-sided deposited TGV was 0.02390 Ω / sq and that of the double-sided deposited TGV was 0.01099 Ω / sq, proving that double-sided deposition can further lower electrical resistance. In addition, the resistivity value was also for the double-sided deposition (2.417×10⁻⁶). -6 Ω·cm) unilateral deposition (2.639×10⁻⁶) -6 It was measured to be lower than Ω·cm, confirming that uniform copper deposition was achieved inside the TGV through the ASE process and that it is effective in improving electrical performance.

[0171]

[0172] Experimental Example 11: Measurement of Electrical Resistance

[0173] To evaluate the electrical characteristics of the Cu / TGV / Cu structure formed through the Atomic Sputtering Epitaxy (ASE) process, resistance was measured using a 4-point probe method. The sample's IV curve was analyzed by applying current in each region (a, b, c, d), and the sheet resistance and resistivity were calculated based on this. In addition, the measured values ​​were compared to verify whether the conductive path of the TGV structure with the ASE process was uniformly formed.

[0174] As a result of the measurement, as shown in FIGS. 18 and 19, the sheet resistance of the Cu / TGV / Cu structure is 0.0864 Ω / sq, and the resistivity is 9.504 × 10⁻⁶. -6It was found to be Ω·cm, confirming that a uniform conduction path was secured through the ASE process. Linear current-voltage characteristics were also confirmed in the IV curve analysis, which means that the ASE process provides lower resistance and uniform electrical characteristics compared to conventional methods. These results suggest that the TGV structure applying the ASE process can possess high reliability in the field of electronic packaging, where high-speed signal transmission and power efficiency are required.

[0175]

[0176] Classification Measurement Value Sheet Resistance [Ω / sq] 0.0864 Resistivity [Ω.cm] 9.504 * 10 -6

[0177]

[0178] Experimental Example 12: Cross-Section SEM Analysis

[0179] To analyze the structure of the Through Glass Via (TGV) before applying the Atomic Sputtering Epitaxy (ASE) process, the interior of the bare TGV without copper deposition was observed using Scanning Electron Microscopy (SEM). Cross-sectional images were acquired at various magnifications (×1,000, ×5,000, ×10,000, ×30,000) to compare and analyze the crystal structure and surface characteristics inside the substrate. Through this, the condition of the TGV inner wall before and after copper deposition was compared, and the effect of the ASE process on the TGV inner wall structure was evaluated.

[0180] As shown in Fig. 20, SEM analysis revealed a rough surface and a polygonal grain structure within the bare TGV where copper was not deposited, confirming that the inner wall of the TGV has a relatively non-uniform structure. These characteristics can be compared with changes in surface roughness (RMS roughness) and grain structure after copper deposition, and it is expected that the inner wall will transform into a more uniform and smooth structure by applying the ASE process. Through this experiment, the effect of process improvement on the inner wall of the TGV can be demonstrated by comparing it with the copper thin film deposition state after the ASE process.

[0181] In addition, as shown in Fig. 21(a), SEM analysis confirmed that the surface of the bare TGV inner wall has a rough and non-uniform grain structure and exhibits relatively high surface roughness. Furthermore, EDS analysis results, as shown in Fig. 21(b), showed that the distribution of silicon and oxygen, the main components of the TGV inner wall, was uniform, and it is expected that the surface characteristics of the inner wall will be improved if a copper (Cu) thin film is uniformly deposited through the ASE process. Through this experiment, the effect of copper thin film deposition after applying the ASE process was compared, and the possibility of improving the electrical and physical properties of the TGV inner wall was confirmed.

[0182] In addition, as shown in Fig. 22, the interior of the TGV hole with copper deposited on both sides was observed using SEM. It was confirmed that a uniform copper thin film was formed on the inner wall of the TGV with copper deposited on both sides through the ASE process, and that the surface had a smoother and finer grain structure compared to the existing bare TGV.

[0183] In addition, as shown in Fig. 23, the interior of the bare TGV and the TGV hole with copper deposited on both sides was compared using SEM for a 10,000x magnification image. It was confirmed that while the inner wall of the bare TGV showed a rough and non-uniform polygonal crystal structure, a fine and uniform copper thin film was deposited in the Cu / TGV / Cu structure.

[0184]

[0185] By means of the above-mentioned solution to the problem, the present invention can effectively solve the problems of the existing TGV process, such as insufficient reliability of bonding between metal and glass, non-uniformity of inner wall coating, and degradation of electrical characteristics.

[0186] In addition, by applying the ASE process, the present invention allows for the direct deposition of copper without an adhesive layer, thereby simplifying the process and reducing manufacturing costs.

[0187] In addition, the present invention can secure high electrical reliability and low resistance values ​​by precisely controlling surface roughness at the nanometer (nm) level, and provides stable conductivity between the upper and lower electrodes.

[0188] In addition, the present invention can be utilized as a process suitable for mass production and minimizing signal loss in next-generation semiconductor and electronic packaging fields such as radio frequency (RF), high-density integrated circuits (HDI), and 3D stacked packaging (3D IC).

[0189]

[0190] As such, those skilled in the art to which the present invention pertains will understand that the technical configuration of the present invention described above can be implemented in other specific forms without altering the technical concept or essential features of the present invention.

[0191] Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting, and the scope of the invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the invention.

Claims

1. A copper thin film is uniformly deposited on the interior and surface of a TGV (Through Glass Via) using an Atomic Sputtering Epitaxy (ASE) process, Characterized by depositing a copper thin film such that the upper and lower electrical resistance of the above TGV is 0.1 Ω or less. Method for depositing a copper thin film in a TGV using atomic layer sputtering epitaxy.

2. In Paragraph 1, Characterized by depositing a copper thin film over the entire inner wall of the TGV such that the thickness variation is ±5 nm or less. Method for depositing a copper thin film in a TGV using atomic layer sputtering epitaxy.

3. In Paragraph 1, Characterized by forming a copper thin film such that the bonding strength between glass and copper is 50 MPa or more, Method for depositing a copper thin film in a TGV using atomic layer sputtering epitaxy.

4. In Paragraph 1, Characterized by forming the copper thin film formed through the above atomic layer sputtering epitaxy process such that the average surface roughness (RMS roughness) is in the range of 4.5 nm or less. Method for depositing a copper thin film in a TGV using atomic layer sputtering epitaxy.

5. In Paragraph 1, Characterized by the fact that the thickness of the copper thin film formed through the above atomic layer sputtering epitaxy process is 2,000 nm or less. Method for depositing a copper thin film in a TGV using atomic layer sputtering epitaxy.

Images