Packaging substrate and its fabrication process

Abstract

This application belongs to the field of circuit board manufacturing technology, specifically disclosing a packaging substrate and its preparation process. The packaging substrate includes a core board and outer layers. The core board is made of a glass substrate. The outer layers are symmetrically arranged on both sides of the core board, with at least one outer layer on each side of the core board. The outer layers include an insulating layer and a conductive layer. Both the core board and the outer layers have positioning holes, which are interconnected. The packaging substrate also includes plastic rivets, which are fitted into the positioning holes and soften during hot pressing to accommodate the thermal expansion of the core board and outer layers. The packaging substrate of this application utilizes the softening of the plastic rivets during hot pressing to flexibly adjust the layers of the packaging substrate, mitigating uneven thermal stress distribution caused by thermal expansion, thereby suppressing warping, cracking, and breakage of the layers of the packaging substrate.

Description

Technical Field

[0001] This application relates to the field of circuit board manufacturing technology, specifically to a laminated structure of a packaging substrate and its preparation method. Background Technology

[0002] Currently, circuit board and packaging substrate manufacturing processes generally still use core boards made of organic-copper composite materials. These core boards have relatively poor surface flatness, which is not conducive to high-density integration. Gradually, glass substrates, with their high flatness of 2-10nm, are replacing these core boards. Glass substrates with high flatness enable the fabrication of ultra-fine circuitry.

[0003] In the lamination process of glass substrates, rigid rivets are generally used for interlayer positioning. For example, stainless steel rivets are used to connect the layers of the glass substrate before the layers are fed into a laminating machine for lamination. During lamination, the layers of the glass substrate will undergo thermal expansion, and the mechanical fixing effect of the rigid rivets can easily cause uneven distribution of thermal stress, which may lead to warping, cracking, or even breakage of the layers of the glass substrate. Summary of the Invention

[0004] This application aims to at least partially solve one of the technical problems in the related art. To this end, embodiments of this application propose a packaging substrate and its manufacturing process, which can utilize the softening of plastic rivets during hot pressing to flexibly adjust the layers of the packaging substrate, alleviate the uneven distribution of thermal stress caused by thermal expansion, and thus suppress warping, cracking, and breakage of the layers of the packaging substrate.

[0005] The packaging substrate of this application embodiment includes: Core board, wherein the core board is composed of a glass substrate; The outer layer plate is symmetrically arranged on both sides of the core plate, and there is at least one outer layer plate on each side of the core plate. The outer layer plate includes an insulating layer and a conductor layer. The core board and the outer layer board are provided with positioning holes. The positioning holes of the core board and the positioning holes of the outer layer board are interconnected. The packaging substrate also includes plastic rivets, which are used to fit in the positioning holes and soften during hot pressing to accommodate the thermal expansion of the core board and the outer layer board.

[0006] In some embodiments, in the outer layer, an insulating layer covers one side of the core plate, and the conductor layer covers the side of the insulating layer opposite to the core plate.

[0007] In some embodiments, the positioning holes are multiple and spaced apart along the edge contour direction of the core plate or the outer layer plate, and the number of plastic rivets is equal to the number of the positioning holes and they correspond one-to-one. The plastic rivets are fitted into the corresponding positioning holes.

[0008] In some embodiments, the interior of the plastic rivet is hollow, so that the plastic rivet can be hot-pressed into a flat shape to fill the positioning hole.

[0009] In some embodiments, the plastic rivet is any one of the following: adhesive kraft paper rivet, polyoxymethylene rivet, nylon rivet, and polyphenylene ether rivet.

[0010] The fabrication process of the packaging substrate in this application includes the following steps: Obtain a core board, wherein the core board is composed of a glass substrate; Outer layers are provided on both sides of the core plate, and the outer layers include an insulating layer and a conductor layer; Positioning holes are provided on the core board and the outer layer board; Plastic rivets are used to fit into the positioning holes to connect the core plate and the outer layer plate together. The plastic rivets are softened during hot pressing to accommodate the thermal expansion of the core plate and the outer layer plate.

[0011] In some embodiments, the fabrication process of the packaging substrate further includes the following steps: The core board and the outer layer are hot-pressed together using a hot press to bond them together.

[0012] In some embodiments, before hot pressing the core board and the outer layer board using a hot press, the preparation process of the packaging substrate further includes the following steps: A buffer membrane is provided on the side of the outer layer plate opposite to the core plate; A pressure equalizing plate is provided on the side of the buffer membrane opposite to the core plate.

[0013] In some embodiments, the buffer membrane comprises a silicone membrane or a fluorine membrane.

[0014] In some embodiments, before the pressure equalization plate is disposed on the side of the buffer film opposite to the core plate, the fabrication process of the encapsulation substrate further includes the following steps: A release film is provided on the side of the buffer film opposite to the core plate.

[0015] Compared with the prior art, this application has the following beneficial effects: In this embodiment of the application, the packaging substrate uses plastic rivets instead of traditional rigid rivets. By utilizing the softening of plastic rivets during hot pressing, the layers of the packaging substrate can be flexibly adjusted. For example, the core board and outer layer board can be flexibly adjusted, which alleviates the uneven distribution of thermal stress caused by the thermal expansion of each layer. The stress distribution can be optimized, thereby suppressing warping, cracking, and breakage of each layer of the packaging substrate. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram showing the distribution of each layer of the packaging substrate before lamination, according to an embodiment of this application.

[0018] Figure 2 This is a schematic diagram of the molding of the packaging substrate after lamination, according to an embodiment of this application.

[0019] Figure 3 This is a schematic diagram of the fabrication process of the packaging substrate according to an embodiment of this application.

[0020] Figure label: 100. Packaging substrate; 10. Core board; 11. Mark point; 20. Outer layer; 21. Insulating layer; 22. Conductor layer; 23. Positioning hole; 24. Exposure hole; 30. Buffer membrane; 40. Release film; 50. Pressure equalizing plate; 60. Plastic rivets. Detailed Implementation

[0021] The embodiments of this application are described in detail below, with examples of these embodiments illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0022] The following is combined with Figures 1 to 3 This application describes the packaging substrate and its fabrication process according to embodiments of the present application.

[0023] refer to Figure 1 In the encapsulation substrate 100 of this application embodiment, plastic rivets 60 are used instead of traditional rigid rivets. By utilizing the softening of plastic rivets 60 during hot pressing, the layers of the encapsulation substrate 100 can be flexibly adjusted, which alleviates the uneven distribution of thermal stress caused by thermal expansion, thereby suppressing the warping, cracking and breakage of the layers of the encapsulation substrate 100.

[0024] like Figure 1 and Figure 2 As shown, the packaging substrate 100 includes a core board 10, an outer layer board 20, and plastic rivets 60.

[0025] The core board 10 is made of a glass substrate.

[0026] The outer layer plates 20 are symmetrically arranged on both sides of the core plate 10, and there is at least one outer layer plate 20 on each side of the core plate 10. For example, there can be two, three, four, etc., on each side of the core plate 10, and the number of outer layer plates 20 on both sides of the core plate 10 is equal and symmetrical to each other. The outer layer plate 20 includes an insulating layer 21 and a conductor layer 22.

[0027] Both the core board 10 and the outer layer 20 are provided with positioning holes 23. The positioning holes 23 of the core board 10 and the positioning holes 23 of the outer layer 20 are interconnected. The plastic rivet 60 is used to fit in the positioning hole 23 and softens during hot pressing to adapt to the thermal expansion of the core board 10 and the outer layer 20.

[0028] In this embodiment of the application, the packaging substrate 100 uses plastic rivets 60 instead of traditional rigid rivets. By utilizing the softening of the plastic rivets 60 during hot pressing, the layers of the packaging substrate 100 can be flexibly adjusted. For example, the core board 10 and the outer layer board 20 can be flexibly adjusted, which alleviates the uneven distribution of thermal stress caused by the thermal expansion of each layer. The stress distribution can be optimized, thereby suppressing the warping, cracking and breakage of each layer of the packaging substrate 100.

[0029] In some embodiments, in the outer layer 20, an insulating layer 21 covers one surface of the core plate 10, and a conductor layer 22 covers the side of the insulating layer 21 facing away from the core plate 10.

[0030] The insulating layer 21 can be a prepreg, epoxy resin insulating film (ABF), etc. The conductor layer 22 can be a copper layer, which can form circuit patterns to constitute a circuit layer. Specifically, the copper layer can be chemically etched to form the desired circuit pattern. The copper layer can also be roughened to increase its adhesion to the insulating layer 21.

[0031] The insulating layer 21 is used to form electrical isolation, and the copper layer is used to form circuit patterns to achieve conductivity.

[0032] Continue to refer to Figure 1 In some embodiments, there are multiple positioning holes 23 and they are spaced apart along the edge contour direction of the core plate 10 or the outer layer plate 20. The number of plastic rivets 60 is equal to that of the positioning holes 23 and they correspond one-to-one. The plastic rivets 60 are fitted into the corresponding positioning holes 23.

[0033] As a preferred embodiment, there can be four positioning holes 23 distributed at the four corners of the edge of the core plate 10 or the outer layer plate 20. There are also four plastic rivets 60, which are disposed in the four positioning holes 23, thereby providing a uniform and comprehensive connection between the core plate 10 and the outer layer plate 20.

[0034] In some embodiments, the interior of the plastic rivet 60 is hollow, so that the plastic rivet 60 can be hot-pressed into a flat shape, thereby filling the positioning hole 23.

[0035] The height of the plastic rivet 60 can be greater than the thickness of the core plate 10 and the outer layer plate 20 stacked together. During hot pressing, the plastic rivet 60 softens under high temperature and deforms inward and outward under pressure, gradually flattening. This ensures that the plastic rivet 60 fills the positioning hole 23, enhances the restraining effect of the plastic rivet 60 on the core plate 10 and the outer layer plate 20, avoids horizontal misalignment of the core plate 10 and the outer layer plate 20, and ensures the accuracy of pressing. The hollow structure of the plastic rivet 60 provides sufficient space for compression towards the center, ensuring reliable deformation of the plastic rivet 60.

[0036] In some embodiments, the plastic rivet 60 is any one of the following: adhesive kraft paper rivet, polyoxymethylene rivet, nylon rivet, and polyphenylene ether rivet.

[0037] Therefore, there are multiple material options for the plastic rivet 60, and one can be selected according to actual needs without any restrictions.

[0038] refer to Figures 1 to 3 The fabrication process of the packaging substrate 100 in this application embodiment includes the following steps: S1. Obtain a core board 10, which is made of a glass substrate.

[0039] S2. Outer layers 20 are provided on both sides of the core board 10. The outer layers 20 include an insulating layer 21 and a conductor layer 22.

[0040] S3. Positioning holes 23 are provided on the core board 10 and the outer layer board 20.

[0041] The positioning holes 23 can be formed on the core board 10 using the existing TGV (Through Glass Via) process. The positioning holes 23 can also be formed on the insulating layer 21 and the conductor layer 22 using the existing laser punching process.

[0042] It should be noted that a reference point, namely Mark point 11, is pre-fabricated on the core board 10. Mark point 11 is used for subsequent optical positioning and identification to ensure the interlayer alignment accuracy of the encapsulation substrate 100 during lamination. In this embodiment, while setting the positioning hole 23, exposure holes 24 can be formed on the insulating layer 21 and the conductor layer 22 by laser cutting. The exposure holes 24 on the insulating layer 21 and the exposure holes 24 on the conductor layer 22 are connected along the thickness direction to expose the Mark point 11 on the core board 10, so that the Mark point 11 can be identified.

[0043] S4. Plastic rivets 60 are used in the positioning holes 23 to connect the core plate 10 and the outer plate 20 together. The plastic rivets 60 are softened during hot pressing to accommodate the thermal expansion of the core plate 10 and the outer plate 20.

[0044] The plastic rivet 60 is used to connect the core plate 10 and the outer layer plate 20 at the initial stage. During hot pressing, it maintains a certain binding effect on the core plate 10 and the outer layer plate 20, while adapting to the thermal expansion of the core plate 10 and the outer layer plate 20, thereby alleviating or even avoiding uneven distribution of thermal stress, and thus suppressing warping, cracking and breakage of each layer of the encapsulation substrate 100.

[0045] In some embodiments, the fabrication process of the packaging substrate 100 further includes the following steps: The core board 10 and the outer layer board 20 are hot-pressed together using a hot press to bond them together.

[0046] The hot press uses high temperature and pressure to melt the resin in the organic layer and generate fluidity. The viscous resin fills all the gaps between the conductor layer 22 and the core board 10, firmly bonding the conductor layer 22 and the core board 10 together.

[0047] refer to Figure 1 In some embodiments, before hot pressing the core board 10 and the outer layer board 20 using a hot press, the fabrication process of the encapsulation substrate 100 further includes the following steps: A buffer membrane 30 is provided on the side of the outer layer 20 away from the core plate 10.

[0048] A pressure equalizing plate 50 is provided on the side of the buffer membrane 30 away from the core plate 10.

[0049] Among them, the equalizing plate 50 can be a steel plate, i.e., a steel plate.

[0050] The pressure applied by the hot press platen to the equalizing platen 50 can be evenly, flatly and stably transmitted to the outer layer plate 20 and the core plate 10 by the equalizing platen 50. The equalizing platen 50 is used to provide a reference plane for the pressing of the outer layer plate 20 and the core plate 10, so as to achieve uniform force on the outer layer plate 20 and the core plate 10 during pressing, and ensure that the pressing is tight and evenly distributed.

[0051] Under high temperature and pressure, the surface of the steel plate generally has microscopic unevenness, and the surface area of ​​the outer layer plate 20 generally has slight thickness differences. Direct pressing will cause local pressure concentration. The buffer film 30 is used to wrap the contact surface between the steel plate and the outer layer plate 20. Through its own elastic deformation, it evenly and smoothly transmits the pressure of the equalizing plate 50 to the conductor layer 22 of the outer layer plate 20, thereby protecting the glass material of the core plate 10.

[0052] In some embodiments, the buffer membrane 30 comprises a silicone membrane or a fluorine membrane.

[0053] It is understood that the silicone film and fluorine film in this embodiment are both high heat-resistant silicone film and fluorine film, which are convenient for use in the hot pressing process of a hot press.

[0054] refer to Figure 1 In some embodiments, before the equalizing plate 50 is provided on the side of the buffer film 30 away from the core plate 10, the preparation process of the encapsulation substrate 100 further includes the following step: providing a release film 40 on the side of the buffer film 30 away from the core plate 10.

[0055] Release film 40 is used to isolate the equalizing plate 50 and prevent the resin of the insulating layer 21 from overflowing and sticking to the equalizing plate 50 during hot pressing, thereby protecting the equalizing plate 50 and making it reusable.

[0056] The subsequent implementation process also includes: drying and curing the laminated packaging substrate 100; cleaning the packaging substrate 100 of residual adhesive, for example, cleaning the packaging substrate 100 using existing plasma cleaning technology.

[0057] After this, processes such as drilling interconnection, hole filling electroplating, and circuit pattern fabrication of conductor layer 22 can be performed on the packaging substrate 100. If it is necessary to fabricate a multilayer outer layer board 20 on one side of the core board 10, the outer layer board 20 can be stacked again, and the hole opening (positioning hole 23), hot pressing and subsequent processes can be repeated to realize the layer-by-layer fabrication of the outer layer board 20 and form a multilayer circuit pattern.

[0058] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0059] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0060] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present application.

Claims

1. A packaging substrate, characterized in that, include: Core board, wherein the core board is composed of a glass substrate; The outer layer plate is symmetrically arranged on both sides of the core plate, and there is at least one outer layer plate on each side of the core plate. The outer layer plate includes an insulating layer and a conductor layer. The core board and the outer layer board are provided with positioning holes. The positioning holes of the core board and the positioning holes of the outer layer board are interconnected. The packaging substrate also includes plastic rivets, which are used to fit in the positioning holes and soften during hot pressing to accommodate the thermal expansion of the core board and the outer layer board.

2. The packaging substrate according to claim 1, characterized in that, In the outer layer, an insulating layer covers one side of the core plate, and a conductor layer covers the side of the insulating layer facing away from the core plate.

3. The packaging substrate according to claim 1, characterized in that, The positioning holes are multiple and spaced apart along the edge contour of the core plate or the outer layer plate. The number of plastic rivets is equal to the number of positioning holes and they correspond one-to-one. The plastic rivets are fitted into the corresponding positioning holes.

4. The packaging substrate according to claim 1, characterized in that, The plastic rivet has a hollow internal structure so that it can be hot-pressed into a flat shape to fill the positioning hole.

5. The packaging substrate according to claim 1, characterized in that, The plastic rivet is any one of the following: adhesive kraft paper rivet, polyoxymethylene rivet, nylon rivet, or polyphenylene ether rivet.

6. A process for fabricating a packaging substrate, characterized in that, include: Obtain a core board, wherein the core board is composed of a glass substrate; Outer layers are provided on both sides of the core plate, and the outer layers include an insulating layer and a conductor layer; Positioning holes are provided on the core board and the outer layer board; Plastic rivets are used to fit into the positioning holes to connect the core plate and the outer layer plate together. The plastic rivets are softened during hot pressing to accommodate the thermal expansion of the core plate and the outer layer plate.

7. The preparation process according to claim 6, characterized in that, Also includes: The core board and the outer layer are hot-pressed together using a hot press to bond them together.

8. The preparation process according to claim 7, characterized in that, Before hot pressing the core board and the outer layer board with a hot press, the method further includes: A buffer membrane is provided on the side of the outer layer plate opposite to the core plate; A pressure equalizing plate is provided on the side of the buffer membrane opposite to the core plate.

9. The preparation process according to claim 8, characterized in that, The buffer membrane includes a silicone membrane or a fluorine membrane.

10. The preparation process according to claim 8, characterized in that, Before the pressure equalization plate is installed on the side of the buffer membrane opposite to the core plate, the method further includes: A release film is provided on the side of the buffer film opposite to the core plate.

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