Manufacturing method and structure of a glass substrate with a high aspect ratio

Abstract

The present invention discloses a manufacturing method and structure of a glass substrate with a high aspect ratio. In this case, low-aspect-ratio vias are respectively formed on two substrates through steps A to C, and then the two substrates are stacked and bonded using anisotropic conductive adhesive, significantly reducing the manufacturing difficulty and improving the via formation accuracy and yield. In step D, a seed layer is deposited on the low-aspect-ratio vias, reducing the process capability requirements, breaking through the industry limitations, saving production costs, and at the same time improving the deposition quality and yield. Steps E and F are based on the already fabricated low-aspect-ratio vias, electroplating to fill the vias, and then using the anisotropic conductive adhesive to the bottom of the vias, greatly reducing the process capability requirements for electroplating via filling, saving costs, ensuring uniform filling, reducing the porosity, and improving the conductivity and reliability. Overall, the solution in this case simplifies the process, reduces the difficulty, improves the efficiency and yield, and has significant technical and economic advantages.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit board processing, and in particular to a manufacturing method and structure of a high-aspect-ratio glass substrate. Background Art

[0002] Currently, for glass or semiconductor silicon-based (or other) glass substrates that require upper and lower layer circuit conduction, conduction is required through a via hole. This via hole needs to be formed on the glass or semiconductor silicon-based (or other) glass substrate, a seed layer is deposited, and then copper is electroplated to fill the hole.

[0003] As shown in the attached picture Figures 1-1 to 1-4 The following is a flow chart of the traditional process for manufacturing glass substrates with high aspect ratio requirements: Figure 1-1 → Hole forming reference Figure 1-2 →Deposition seed layer reference Figure 1-3 → Electroplating Metal Filling Reference Figure 1-4 Chinese publication number CN103648242A provides a vacuum filling method for high-aspect ratio blind and buried vias. By using drilled copper foil to assist in filling the high-aspect ratio blind and buried vias on a PCB glass substrate, the method can effectively fill the high-aspect ratio blind and buried vias, prevent gaps in the blind and buried vias during lamination, and ensure that the vias are fully filled with glue without cracks or bubbles.

[0004] However, the above traditional high aspect ratio glass substrate methods and the methods in the comparative documents both directly form high aspect ratio blind buried vias on the glass substrate, which has the following problems:

[0005] 1. Difficulty in producing vias: Due to material, process or equipment limitations, it is difficult to produce vias with high aspect ratios;

[0006] 2. Complex hole-forming process: Since the requirement is to form holes with high aspect ratios, the one-time production of glass substrate holes may involve multiple steps and the control of multiple process parameters. This may lead to complex processes, increased costs and reduced yields, making it difficult to meet high-precision hole-forming requirements;

[0007] 3. High requirements for seed layer deposition: Due to the special shape and structure of the vias, existing technologies also require more complex processes and higher precision when depositing the seed layer on the inner wall of high-aspect-ratio vias, further increasing costs and reducing yields.

[0008] 4. Difficulty in electroplating via filling: Existing electroplating via filling may face problems such as uneven filling and high porosity, which is particularly prominent in high-aspect-ratio vias.

[0009] Therefore, how to overcome the above-mentioned defects has become an important issue to be solved urgently by those skilled in the art. Summary of the Invention

[0010] The present invention overcomes the deficiencies of the above-mentioned technologies and provides a manufacturing method and structure for a glass substrate with a high aspect ratio.

[0011] To achieve the above object, the present invention adopts the following technical solutions:

[0012] In the first aspect, the present case provides a manufacturing method for a glass substrate with a high aspect ratio, including the following steps:

[0013] Step A: Provide at least two untreated glass substrates, namely the first glass substrate 1 and the second glass substrate 2;

[0014] Step B: Form low-aspect-ratio vias on the first glass substrate 1 and the second glass substrate 2 respectively;

[0015] Step C: Use anisotropic conductive adhesive to stack and bond the two glass substrates together, and the low-aspect-ratio vias of the two glass substrates are aligned vertically;

[0016] Step D: Deposit a seed layer on the surface of each glass substrate, including depositing a seed layer on the surface of all low-aspect-ratio vias;

[0017] Step E: Fill the conductive metal in all low-aspect-ratio vias by electroplating;

[0018] Step F: Use a high-temperature and high-pressure process to make the bottoms of the vertically aligned low-aspect-ratio vias conduct, so as to form a glass substrate structure with a high aspect ratio.

[0019] Preferably, the anisotropic conductive adhesive is a colloid that conducts in the vertical z-axis direction after a certain high-temperature and high-pressure process, does not conduct in the x and y axis directions, and has the function of bonding the upper and lower base materials at the same time.

[0020] Preferably, when using the anisotropic conductive adhesive to stack and bond the two glass substrates together in step B, it is also necessary to be in a vacuum environment for vacuum bonding.

[0021] Preferably, the conductive metal in step F is copper metal.

[0022] Preferably, before depositing the seed layer in step D, it also includes pre-treating the surfaces of the first glass substrate 1 and the second glass substrate 2 to remove surface contaminants and oxides.

[0023] In the second aspect, the present case provides a glass substrate structure with a high aspect ratio, which is manufactured according to the manufacturing method described in the first aspect.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The solution of this case first forms low-aspect-ratio vias on two glass substrates through steps A to C, and then uses anisotropic conductive adhesive to stack and bond the two glass substrates, so that the high-aspect-ratio via that originally needed to be made in one go is decomposed into two low-aspect-ratio vias, thereby significantly reducing the difficulty of making the vias and making it easier to achieve high-precision hole formation. The solution of this case greatly simplifies the hole-forming process by making low-aspect-ratio vias in two steps and then aligning and bonding them, reducing the difficulty of controlling process parameters and improving yield and production efficiency. In this case, by first depositing a seed layer on the low-aspect-ratio via through step D, the process capability requirements for depositing the seed layer are greatly reduced. This not only breaks through the industry's process capability limitations, but also greatly saves production costs, reduces the difficulty of depositing the seed layer, and improves deposition quality and yield. In this case, through steps E and F, electroplating is performed on the already fabricated low-aspect-ratio vias. Anisotropic conductive adhesive is then used to fill the bottom of the vias, forming the final high-aspect-ratio glass substrate structure. This significantly reduces the process capability requirements for electroplating via filling, not only breaking through the industry's process capability limitations but also significantly saving production costs. At the same time, it can ensure uniform filling, reduce porosity, and improve conductivity and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 1 is a flow chart of a method for manufacturing a high aspect ratio glass substrate according to the first embodiment of the present invention.

[0027] Figures 1-1 to 1-4 Shown is a conventional process flow chart for manufacturing a glass substrate with high aspect ratio requirements.

[0028] Figures 2-1 to 2-7 This is a process flow chart of the method for manufacturing a high aspect ratio glass substrate in Example 1.

[0029] in, Figure 2-1 1 is a schematic diagram of the structure of two untreated glass substrates in step A of embodiment 1. Figure 2-2 1 is a schematic diagram of the structure after forming a low aspect ratio via hole in step B of embodiment 1. Figure 2-3 This is a schematic diagram of the structure in which one of the glass substrates in step C is coated with anisotropic conductive adhesive. Figure 2-4 This is a schematic diagram of the structure after the two glass substrates are stacked and bonded together in step C. Figure 2-5 It is a schematic diagram of the structure after the seed layer is deposited on the surface of the glass substrate in step D. Figure 2-6 This is a schematic diagram of the structure after etching all low aspect ratio vias and filling them with conductive metal in step E. Figure 2-7 This is a schematic diagram of the structure after the bottom of the low aspect ratio via hole is connected in step F, and is also a schematic diagram of the structure of the high aspect ratio glass substrate finally formed. Figure 2-7The anisotropic conductive adhesive 5 has been treated under high temperature and high pressure, so it appears different from other figures. Detailed Description of the Invention

[0030] The features of the present invention and other related features will be further described in detail through the following embodiments for the understanding of those skilled in the art:

[0031] Embodiment 1

[0032] As Figure 1 and Figures 2-1 to 2-7 shown, a method for manufacturing a glass substrate with a high aspect ratio includes the following steps:

[0033] Step A: Provide at least two untreated glass substrates, namely the first glass substrate 1 and the second glass substrate 2;

[0034] Step B: Form low aspect ratio vias 3 on the first glass substrate 1 and the second glass substrate 2 by drilling / laser drilling;

[0035] Form low aspect ratio vias respectively; In specific implementation, the thickness and aperture of the first glass substrate 1 and the second glass substrate 2 are selected according to the required characteristics;

[0036] Step C: Use the anisotropic conductive adhesive 5 to stack and bond the two glass substrates together, and align the low aspect ratio vias of the two glass substrates up and down; In specific implementation, apply the anisotropic conductive adhesive on the surface of the first glass substrate, and stack the other glass substrate on the first glass substrate by applying the anisotropic conductive adhesive.

[0037] Step D: Deposit a seed layer 4 on the surface of each glass substrate, including depositing a seed layer on the surface of all low aspect ratio vias; In specific implementation, the step of depositing the seed layer is different from that in the prior art where a high aspect ratio via is first formed for deposition. This step can deposit only on the low aspect ratio vias arranged on the upper and lower sides respectively, greatly reducing the difficulty of depositing the seed layer;

[0038] Step E: Fill the conductive metal in all low aspect ratio vias by electroplating;

[0039] Step F: Use a high temperature and high pressure process to make the bottoms of the low aspect ratio vias aligned up and down conduct, so as to form a glass substrate structure with a high aspect ratio. In specific implementation, the specific settings of high temperature and high pressure can be set according to the data sheet of the corresponding anisotropic conductive adhesive. Generally, the high temperature range is: \(130 - 210^{\circ}C\), and the high pressure range is \(30 - 80[MPa]*3\).

[0040] In specific implementation, when a certain feature, such as the depth of a via hole, is much greater than its diameter or width, the aspect ratio of this feature is called a high aspect ratio; this usually means that in the design of a multi-layer glass substrate, in order to increase the number of layers, reduce the size, or improve the performance, it is necessary to fabricate holes with a high depth-to-diameter ratio or a high width-to-diameter ratio. The design of a glass substrate with a high aspect ratio can allow for more layers and a more complex circuit layout, thus helping to improve the performance and reliability of the circuit board. Contrary to the high aspect ratio, when the ratio of the depth of a certain feature on the glass substrate to its diameter or width is low, the aspect ratio of this feature is called a low aspect ratio.

[0041] As described above, in the solution of this case, first, via holes with a low aspect ratio are formed on two glass substrates respectively through steps A to C, and then the two glass substrates are stacked and bonded using anisotropic conductive adhesive, so that the high aspect ratio via holes that originally need to be fabricated in one go are decomposed into two via holes with a low aspect ratio, thus significantly reducing the fabrication difficulty of the via holes and making it easier to achieve high-precision hole formation. And in the solution of this case, by fabricating via holes with a low aspect ratio in two steps and then aligning and bonding them, the hole formation process is greatly simplified, the control difficulty of process parameters is reduced, and the yield and production efficiency are improved. In this case, through step D, by first depositing a seed layer on the via holes with a low aspect ratio, the process capability requirements for depositing the seed layer are significantly reduced, which can not only break through the process capability limitations in the industry, but also greatly save production costs, and at the same time reduce the difficulty of depositing the seed layer and improve the deposition quality and yield. In this case, through steps E and F, based on the via holes with a low aspect ratio that have been fabricated, electroplating is carried out to fill the holes, and then the bottom of the via hole is filled with anisotropic conductive adhesive to form the final high aspect ratio glass substrate structure, which also significantly reduces the process capability requirements for electroplating to fill the holes, can not only break through the process capability limitations in the industry, but also greatly save production costs, and at the same time can ensure uniform filling, reduce the porosity, and improve the electrical conductivity and reliability.

[0042] As a preferred implementation manner, the glass substrate is a glass substrate or a commonly used silicon-based glass substrate in semiconductors. In this way, the glass substrate has a high surface flatness and low roughness, providing an ideal platform for the manufacture of semiconductor devices, greatly increasing the interconnection density between chips, and thus improving the performance of the entire chip. The manufacturing technology of silicon glass substrates is very mature, with a large number of manufacturing processes and equipment support, which makes it easier to achieve quality control and cost control in the production process.

[0043] As a specific implementation manner, after the anisotropic conductive adhesive undergoes a certain high-temperature and high-pressure process, it conducts electricity in the up and down z-axis directions but does not conduct electricity in the x and y-axis directions, and at the same time has the function of bonding the upper and lower substrate materials. In this way, after the anisotropic conductive adhesive undergoes a certain high-temperature and high-pressure process, it conducts electricity in the up and down Z-axis directions, does not conduct electricity in the X and Y-axis directions, and at the same time has the function of bonding the upper and lower substrate materials, which can ensure the stable transmission of current in the vertical direction, and at the same time effectively avoid the short-circuit problem between adjacent electrodes, and improve the stability and reliability of the circuit.

[0044] As a preferred implementation manner, when using the anisotropic conductive adhesive to stack and bond two glass substrates together in step B, it is also necessary to be in a vacuum environment for vacuum lamination. In this way, in a vacuum environment, the air and dust between the glass substrates can be eliminated, avoiding their adverse effects on the lamination effect of the conductive adhesive, which helps to ensure that the conductive adhesive can be laminated evenly and tightly between the two glass substrates, thereby improving the lamination quality. At the same time, laminating in a vacuum environment can effectively exclude air and avoid the generation of bubbles and wrinkles.

[0045] As a preferred implementation manner, the conductive metal described in step E is copper metal.

[0046] As a preferred implementation manner, before depositing the seed layer in step D, it also includes pre-treating the surfaces of the first glass substrate 1 and the second glass substrate 2 to remove surface contaminants and oxides, and improve the adhesion and uniformity of the seed layer.

[0047] Embodiment 2

[0048] A high aspect ratio glass substrate, characterized in that it is made according to the manufacturing method described in Embodiment 1.

[0049] In summary, the manufacturing method of the high aspect ratio glass substrate proposed in the solution of this case shows significant beneficial effects in reducing the manufacturing difficulty of vias, simplifying the via formation process, reducing the requirements for depositing the seed layer, solving the difficulty of electroplating to fill vias, and improving production efficiency and reducing costs.

[0050] As described above, what this case protects is a manufacturing method and structure of a high aspect ratio glass substrate, and all technical solutions identical or similar to this case should be regarded as falling within the protection scope of this case.

Claims

1. A method for manufacturing a glass substrate with a high aspect ratio, characterized in that, It includes the following steps: Step A: Provide at least two untreated glass substrates, namely the first glass substrate (1) and the second glass substrate (2); Step B: Form low aspect ratio vias on the first glass substrate (1) and the second glass substrate (2) respectively; Step C: Stack and bond the two glass substrates together vertically using anisotropic conductive adhesive, and the low aspect ratio vias of the two glass substrates are vertically aligned one by one; Step D: Deposit a seed layer on the surface of each glass substrate, including depositing a seed layer on the surface of all low aspect ratio vias; Step E: Fill the conductive metal in all low aspect ratio vias by electroplating; Step F: Use a high temperature and high pressure process to make the bottoms of the vertically aligned low aspect ratio vias conduct, so as to form a high aspect ratio glass substrate structure; Among them, when the two glass substrates are stacked and bonded together vertically using anisotropic conductive adhesive in Step C, it is also necessary to be in a vacuum environment for vacuum bonding.

2. The manufacturing method of the high aspect ratio glass substrate according to claim 1, wherein The anisotropic conductive adhesive is a colloid that conducts in the vertical z-axis direction and does not conduct in the x and y-axis directions after a certain high temperature and high pressure process, and at the same time has the function of bonding the upper and lower base materials.

3. The manufacturing method of the high aspect ratio glass substrate according to claim 1 or 2, characterized in that, The conductive metal described in Step E is copper metal.

4. The manufacturing method of the high aspect ratio glass substrate according to claim 1, wherein Before depositing the seed layer in Step D, it also includes pre-treating the surfaces of the first glass substrate (1) and the second glass substrate (2) to remove surface contaminants and oxides.

5. A glass substrate structure with a high aspect ratio, characterized in that, It is made by the manufacturing method according to any one of claims 1-4.

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