Manufacturing method and structure of high aspect ratio glass substrate

Abstract

The invention discloses a manufacturing method and a structure of a high aspect ratio glass substrate, according to the scheme, via holes with low aspect ratios are respectively formed in two substrates through steps A to C, and then the two substrates are stacked and bonded by using an anisotropic conductive adhesive, so that the manufacturing difficulty is remarkably reduced, and the hole forming precision and the yield are improved. And in the step D, the seed layer is deposited on the via hole with the low aspect ratio, so that the process capability requirement is reduced, the limitation of the industry is broken through, the production cost is saved, and the deposition quality and yield are improved at the same time. And the step E and the step F are used for carrying out electroplating hole filling based on the manufactured low aspect ratio via hole, and then the anisotropic conductive adhesive is used for conducting the bottom of the via hole, so that the process capability requirement of electroplating hole filling is greatly reduced, the cost is saved, uniform filling is ensured, the porosity is reduced, and the conductivity and the reliability are improved. On the whole, according to the scheme, the process is simplified, the difficulty is reduced, the efficiency and the yield are improved, and remarkable technical and economic advantages are achieved.

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] At present, for glass or silicon-based (or other) glass substrates commonly used in semiconductors, there is a need for upper and lower layer circuit conduction, which needs to be connected through a via hole. This via hole needs to be formed on the glass or silicon-based (or other) glass substrate commonly used in semiconductors, a seed layer is deposited, and then copper is electroplated to fill the hole.

[0003] As shown in the attached picture Figure 1-1 to Figure 1-4 The figure shows the traditional process flow chart of glass substrate manufacturing with high aspect ratio requirements. The manufacturing method is as follows: Figure 1-1 → Hole forming reference Figure 1-2 →Deposition seed layer reference Figure 1-3 → Electroplating metal filling reference Figure 1-4 China Publication No. CN103648242A provides a vacuum filling method for high aspect ratio blind buried vias, which uses drilled copper foil to assist in filling the high aspect ratio blind buried vias of the PCB glass substrate, so that the high aspect ratio blind buried vias can be effectively filled, and the blind buried vias can be prevented from lacking glue during lamination, and the holes can be filled with full glue without cracks or bubbles.

[0004] However, the above conventional high aspect ratio glass substrate method and the comparative document method both directly form high aspect ratio blind buried vias on the glass substrate, which has the following problems:

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

[0006] 2. Complex hole-forming process: Since the requirement is to form holes with high aspect ratios, one-time production of glass substrate holes may involve multiple steps and control of multiple process parameters, which 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 depositing the seed layer: Due to the special shape and structure of the via hole, the existing technology also requires more complex processes and higher precision requirements when depositing the seed layer on the inner wall of the high aspect ratio via hole, which further increases the cost and reduces the yield;

[0008] 4. Difficulty in electroplating via filling: Existing electroplating via filling may face problems such as uneven filling and high porosity, especially 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 shortcomings of the above-mentioned technology and provides a method and structure for manufacturing a glass substrate with a high aspect ratio.

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

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

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

[0014] Step B, forming low aspect ratio via holes on the first glass substrate 1 and the second glass substrate 2 respectively;

[0015] Step C, using anisotropic conductive adhesive to stack and bond two glass substrates together, and align the low aspect ratio via holes of the two glass substrates one by one;

[0016] Step D, depositing 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, filling all low aspect ratio vias with conductive metal by electroplating;

[0018] Step F: Using a high temperature and high pressure process, the bottoms of the low aspect ratio via holes aligned one by one are connected to form a high aspect ratio glass substrate structure.

[0019] Preferably, the anisotropic conductive adhesive is a colloid that is conductive in the upper and lower z-axis directions but not conductive in the x- and y-axis directions after a certain high temperature and high pressure process, and has the function of bonding the upper and lower substrate materials.

[0020] Preferably, when the two glass substrates are stacked and bonded together using anisotropic conductive adhesive in step B, a vacuum environment is required for vacuum bonding.

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

[0022] Preferably, before depositing the seed layer in step D, the process further includes pre-treating the surfaces of the first glass substrate 1 and the second glass substrate 2 to remove pollutants and oxides on the surfaces.

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

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The scheme 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 needs 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 scheme 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, which not only breaks through the industry's process capability limitations, but also greatly saves production costs, and reduces the difficulty of depositing the seed layer and improves the deposition quality and yield. In this case, through steps E and F, electroplating is performed based on the already manufactured low-aspect ratio via holes, and then the bottom of the via holes is made using anisotropic conductive adhesive to form the final high-aspect ratio glass substrate structure, which greatly reduces the process capability requirements for electroplating via filling. It not only breaks through the industry's process capability limitations, but also greatly saves 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 schematic diagram of a process for manufacturing a high aspect ratio glass substrate according to the first embodiment of the present invention.

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

[0028] Figure 2-1 to Figure 2-7 It is a manufacturing process flow chart of the manufacturing method of the high aspect ratio glass substrate in the first embodiment.

[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 It is a schematic diagram of the structure after forming a via hole with a low aspect ratio in step B of the first embodiment. Figure 2-3 It 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 It is a schematic diagram of the structure after the two glass substrates are stacked up 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 It is a schematic diagram of the structure after the bottom of the low aspect ratio via hole is connected in step F, and it 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 with high temperature and high pressure, so the display is different from other figures. DETAILED DESCRIPTION

[0030] The features of the present invention and other related features are further described in detail below through embodiments to facilitate understanding by those skilled in the art:

[0031] Embodiment 1

[0032] like Figure 1 as well as Figure 2-1 to Figure 2-7 As shown, a method for manufacturing a high aspect ratio glass substrate comprises the following steps:

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

[0034] Step B, forming a low aspect ratio via hole 3 on the first glass substrate 1 and the second glass substrate 2 by drilling or laser punching;

[0035] Forming low aspect ratio via holes respectively; in a 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, using anisotropic conductive adhesive 5 to stack and bond two glass substrates together, and align the low aspect ratio via holes of the two glass substrates one by one; in specific implementation, anisotropic conductive adhesive is applied on the surface of the first glass substrate, and the other glass substrate is stacked on the first glass substrate by applying anisotropic conductive adhesive.

[0037] Step D, depositing a seed layer 4 on the surface of each glass substrate, including depositing the seed layer on the surface of all low aspect ratio via holes; in specific implementation, the seed layer deposition step is different from the prior art in which a high aspect ratio via hole is first formed for deposition, and this step can only deposit the low aspect ratio via holes arranged on the upper and lower sides, which greatly reduces the difficulty of depositing the seed layer;

[0038] Step E, filling all low aspect ratio vias with conductive metal by electroplating;

[0039] Step F: Using a high temperature and high pressure process, the bottoms of the low aspect ratio vias aligned one by one are connected to form a high aspect ratio glass substrate structure. In specific implementation, the specific high temperature and high pressure settings can be set according to the data sheet of the corresponding anisotropic conductive adhesive. Usually, the high temperature range is: 130-210°C, and the high pressure range is 30-80 [MPa] * 3.

[0040] In practice, when the depth of a feature, such as a via, is much greater than its diameter or width, the aspect ratio of the feature is referred to as a high aspect ratio; this usually means that in a multi-layer glass substrate design, in order to increase the number of layers, reduce size, or improve performance, it is necessary to manufacture holes with a high depth-to-diameter ratio or a high width-to-diameter ratio. Glass substrate designs with high aspect ratios can allow for more layers and more complex circuit layouts, which can help improve the performance and reliability of the circuit board. In contrast to a high aspect ratio, when the ratio of the depth of a feature on a glass substrate to its diameter or width is low, the aspect ratio of the feature is referred to as a low aspect ratio.

[0041] As described above, the scheme of this case first forms low-aspect-ratio vias on two glass substrates respectively 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 needs 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 scheme 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, which not only breaks through the industry's process capability limitations, but also greatly saves production costs, and reduces the difficulty of depositing the seed layer and improves the deposition quality and yield. In this case, through steps E and F, electroplating is performed based on the already manufactured low-aspect ratio via holes, and then the bottom of the via holes is made using anisotropic conductive adhesive to form the final high-aspect ratio glass substrate structure, which greatly reduces the process capability requirements for electroplating via filling. It not only breaks through the industry's process capability limitations, but also greatly saves production costs. At the same time, it can ensure uniform filling, reduce porosity, and improve conductivity and reliability.

[0042] As a preferred embodiment, the glass substrate is a glass substrate or a silicon-based glass substrate commonly used 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 improving the interconnection density between chips, thereby improving the performance of the entire chip. The manufacturing technology of silicon glass substrates is very mature, and there are a large number of manufacturing processes and equipment to support it, which makes it easier to achieve quality control and cost control in the production process.

[0043] As a specific implementation, the anisotropic conductive adhesive is conductive in the upper and lower z-axis directions after a certain high temperature and high pressure process, but not conductive in the x and y-axis directions, and has the function of bonding the upper and lower substrate materials. In this way, the anisotropic conductive adhesive is conductive in the upper and lower z-axis directions after a certain high temperature and high pressure process, but not conductive in the x and y-axis directions, and has the function of bonding the upper and lower substrate materials, which can ensure the stable transmission of current in the vertical direction, effectively avoid the short circuit problem between adjacent electrodes, and improve the stability and reliability of the circuit.

[0044] As a preferred embodiment, when the two glass substrates are stacked and bonded together using anisotropic conductive adhesive in step B, vacuum bonding is also required. In this way, in a vacuum environment, air and dust between the glass substrates can be eliminated to avoid their adverse effects on the bonding effect of the conductive adhesive, which helps to ensure that the conductive adhesive can be evenly and tightly bonded between the two glass substrates, thereby improving the bonding quality. At the same time, bonding in a vacuum environment can effectively remove air and avoid the generation of bubbles and wrinkles.

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

[0046] As a preferred embodiment, before depositing the seed layer in step D, the surface of the first glass substrate 1 and the second glass substrate 2 is pretreated to remove pollutants and oxides on the surface 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 manufactured according to the manufacturing method described in the first embodiment.

[0049] In summary, the method for manufacturing a high aspect ratio glass substrate proposed in this case shows significant beneficial effects in reducing the difficulty of making vias, simplifying the hole forming process, reducing the requirements for deposited seed layers, solving the difficulties of electroplating hole filling, and improving production efficiency and reducing costs.

[0050] As mentioned above, this case protects a method and structure for manufacturing a high aspect ratio glass substrate, and all technical solutions that are the same or similar to this case should be deemed to fall within the protection scope of this case.

Claims

1. A method for manufacturing a high aspect ratio glass substrate, characterized in that: The steps include: Step A, providing at least two untreated glass substrates, namely a first glass substrate (1) and a second glass substrate (2); Step B, forming low aspect ratio via holes on the first glass substrate (1) and the second glass substrate (2), respectively; Step C, using anisotropic conductive adhesive to stack and bond two glass substrates together, and align the low aspect ratio via holes of the two glass substrates one by one; Step D, depositing 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, filling all low aspect ratio vias with conductive metal by electroplating; Step F: Using a high temperature and high pressure process, the bottoms of the low aspect ratio via holes aligned one by one are connected to form a high aspect ratio glass substrate structure.

2. The method for manufacturing a high aspect ratio glass substrate according to claim 1, characterized in that: The anisotropic conductive adhesive is a colloid that is conductive in the upper and lower z-axis directions but not conductive in the x- and y-axis directions after a certain high temperature and high pressure process, and has the function of bonding the upper and lower substrate materials.

3. The method for manufacturing a high aspect ratio glass substrate according to claim 1, wherein: When the two glass substrates are stacked and bonded together using anisotropic conductive adhesive in step B, a vacuum environment is required for vacuum bonding.

4. The method for manufacturing a high aspect ratio glass substrate according to any one of claims 1 to 3, characterized in that: The conductive metal in step E is copper metal.

5. The method for manufacturing a high aspect ratio glass substrate according to claim 1, wherein: Before depositing the seed layer in step D, the method further includes pre-treating the surfaces of the first glass substrate (1) and the second glass substrate (2) to remove pollutants and oxides on the surfaces.

6. A high aspect ratio glass substrate structure, characterized in that: It is made according to the production method according to any one of claims 1 to 5.

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