A high-frequency unit dielectric structure and a method for manufacturing a rigid-flexible board

Abstract

The present invention discloses a method for manufacturing a high-frequency unit dielectric structure and a rigid-flexible board. The method comprises: manufacturing a trough on the ceramic substrate, wherein the high-frequency unit dielectric structure is divided into a reserved area and a non-reserved area by the trough; manufacturing an ink layer on the ceramic substrate; manufacturing a release layer on the ink layer, wherein the release layer covers the non-reserved area and the trough; refining the release layer; developing the ink layer; and filling the step with a prepreg to form the high-frequency unit dielectric structure. The method comprises: manufacturing a flexible board; alternatingly arranging the flexible board and the high-frequency unit dielectric structure and laminating the entire board; and removing the high-frequency unit dielectric structure in the non-reserved area to form the rigid-flexible board. The high-frequency unit dielectric structure of the present invention is simple to manufacture, and the rigid-flexible board is modularly manufactured, so that a high-frequency rigid-flexible board product with a large step can be manufactured under simple and reliable conditions.

Description

Technical Field

[0001] The present invention relates to the field of circuit board manufacturing, and in particular to a high-frequency unit dielectric structure and a method for manufacturing a rigid-flexible board. Background Art

[0002] The rigid board part of the rigid-flexible board has good electronic component support performance, the flexible part has good bending performance or three-dimensional assembly performance, and the overall reliability is good, which can meet the application needs of many different scenarios. Therefore, the application of rigid-flexible boards is becoming more and more extensive.

[0003] Based on the development of high-frequency networks, the application of high-frequency electronic components is becoming more and more extensive. For some high-frequency electronic components that need to have good circuit performance, smaller assembly space, and more flexible assembly characteristics, it is necessary to use dielectric layer materials with high-frequency performance, with a large drop, and a design method that includes multiple flexible boards is required to meet the requirements; the large drop means that the rigid boards between the flexible boards have a larger spacing, so as to avoid mutual interference when transmitting high-frequency signals between the circuit layers; due to the complex structure of such products, their processing difficulty is also relatively large.

[0004] At present, for high-frequency and large-drop rigid-flex boards, the dielectric layer that does not need to be retained is generally opened first, and then replaced with an inert release layer. After going through processes such as lamination, the cover is finally removed from the edge of the release layer to achieve the effect of a large drop.

[0005] However, this method has the following main problems:

[0006] (1) If the rigid-flex board contains multiple flexible board parts, it is difficult to use this method to make the inner circuit layer because the inner circuit layer cannot be made by uncovering the cover;

[0007] (2) The method of replacing the release layer at the window of the dielectric layer is adopted. Since the cover needs to be removed, it is necessary to ensure that the material properties of the dielectric layer and the release layer have a large difference. However, the larger the use area of ​​the release layer, the more likely it is that bulges or pits will be generated at the junction of the release layer and the dielectric layer during the lamination process. The expansion and contraction compensation coefficient of the two is difficult to control, resulting in bulges or depressions on the surface of the circuit board. In severe cases, it may lead to delamination and explosion of the circuit board.

[0008] (3) If the dielectric layer is made of high-frequency material, the processing becomes more difficult, making the above-mentioned problems (1) and (2) more prominent.

[0009] Based on the above problems, it is necessary to provide a method for manufacturing a high-frequency rigid-flexible board with a large drop, so as to meet the manufacturing requirements of such products and improve the reliability of the products. Summary of the Invention

[0010] Based on this, the present invention provides a method for manufacturing a high-frequency unit dielectric structure and a rigid-flexible board, which can realize the convenient manufacturing of the high-frequency unit dielectric structure of the inner layer by uncovering the cover when the dielectric layer adopts high-frequency materials. The present invention adopts the method of separately processing the high-frequency unit dielectric structure and the flexible board layer, and then alternately arranges them for overall processing, which can ensure that the processing of the circuit pattern of the flexible board layer is not affected by the high-frequency unit dielectric structure, provides a convenient processing method for manufacturing rigid-flexible boards with large drop, and effectively improves the process capability and reliability.

[0011] In a first aspect, the present invention provides a method for manufacturing a high-frequency unit dielectric structure, comprising the following steps:

[0012] S100: Taking a ceramic substrate, making a slot body on the ceramic substrate, wherein the high-frequency unit dielectric structure is divided into a reserved area and a non-reserved area by the slot body;

[0013] S110: forming an ink layer on the ceramic substrate;

[0014] S120: forming a release layer on the ink layer, wherein the release layer covers the non-retained area and the tank body;

[0015] S130: finishing the release layer;

[0016] S140: developing the ink layer;

[0017] S150: Filling the gap with a prepreg to form the high-frequency unit dielectric structure.

[0018] It should be further explained that the present invention adopts modularization to produce rigid-flexible boards. The high-frequency unit dielectric structure is first manufactured to form a unit module that can effectively support the production of rigid-flexible boards. The overall production method must be able to achieve good bonding performance of the rigid board during the subsequent production of the rigid-flexible board, and also achieve the characteristic that the flexible board area can be easily peeled off. Therefore, the combination of ceramic substrate + trough body + ink layer + release layer can achieve the feasibility and reliability of subsequent modular production and the convenience of peeling production.

[0019] It should be further explained that the width of the groove body is small and can be regarded as a line relative to the area of ​​the entire ceramic substrate. Therefore, the high-frequency unit dielectric structure can be divided into a reserved area and a non-reserved area with reference to the groove body. The reserved area eventually forms the rigid board area of ​​the rigid-flexible composite board, and the non-reserved area is removed in the final production process of the rigid-flexible composite board, that is, the cover is removed; the use of an ink layer can improve the bonding force between the ceramic substrate and the release layer, and prevent the problem of the release layer being difficult to adhere; the use of a release layer can provide a good layering basis for subsequent cover removal and facilitate processing.

[0020] Optionally, the ceramic substrate is a ceramic powder composite epoxy resin substrate.

[0021] Optionally, the trough body is formed into a half trough body by laser engraving, and the trough bodies are symmetrically distributed on two sides of the ceramic substrate.

[0022] It should be further explained that the laser groove forms a half groove body, and the depth of a single half groove body does not exceed 1 / 3 of the thickness of the ceramic substrate, providing a dividing groove that can be removed for subsequent cover production. Grooves are made on both sides of the ceramic substrate to further improve the operability of the cover.

[0023] Optionally, the ink layer is prepared by applying ink on the ceramic substrate through silk screen printing followed by pre-baking, and the ink layer is a black ink layer.

[0024] It should be further explained that since only pre-baking is performed here and no post-baking is performed, after pre-baking, the ink is in a semi-cured state, which can provide a good adhesion basis for the production of the release layer and meet the development basis for the subsequent development of the ink layer to remove the retained area. If the ink is post-baked, it will be completely cured and it will be difficult to achieve the above effect; black ink is used as the ink, which has poor light transmittance and can prevent the laser from damaging the ceramic substrate layer when the excess release layer is subsequently laser ablated.

[0025] It should be further explained that the thickness of the ink is 20 μm to 40 μm; the pre-baking is carried out at 75°C for 30 minutes;

[0026] Optionally, the release layer is made by laminating the release layer on the ink layer using a lamination film, and the release layer is a release layer made of PTFE or ETFE material.

[0027] It should be further explained that PTFE or ETFE materials have strong inertness and can play a good release role in the manufacturing process; the thickness of the release layer is 10μm~30μm, the accuracy of the lamination is ±10μm, and when laminating the release layer, it is generally necessary to pre-enlarge it by 10μm to prevent insufficient lamination size.

[0028] Optionally, the finishing is to trim the release layer in the reserved area by laser ablation.

[0029] It should be further explained that after the above-mentioned film pressing, a part of the film will extend into the reserved area, so the film extending into the reserved area needs to be removed. The use of laser finishing can effectively remove the film extending into the reserved area, and the accuracy can meet the production requirements.

[0030] Optionally, the developing step is to develop the ink layer in a process of exposure→development.

[0031] It should be further explained that the ink layer to be removed is the ink layer located in the reserved area. Since the non-reserved area is completely covered by the release layer, the entire area can be directly exposed and developed, that is, the ink layer in the reserved area can be removed.

[0032] Optionally, the step of filling the gap with a prepreg is to fill the gap formed between the ink layer and the release layer on the ceramic substrate with the prepreg, and the prepreg is a ceramic powder composite epoxy resin prepreg.

[0033] It should be further explained that in the aforementioned production process, an ink layer and a release layer are formed in the non-retained area. The ink layer and the release layer have a certain thickness, but the non-retained area is the rigid area of ​​the rigid-flexible board and needs to be completely a ceramic substrate to ensure subsequent effective combination with the flexible board. Therefore, during the design, a filling position for the ceramic substrate with a drop position consistent with the thickness of the ink layer and the release layer is reserved in the reserved area. The same ceramic substrate is used to fill the drop so that the thickness reaches the design requirement, and the filled ceramic substrate is filled by rapid pressing.

[0034] In a second aspect of the present application, a method for manufacturing a rigid-flexible board is provided, comprising the following steps:

[0035] S200: manufacturing a flexible board required for laminating the rigid-flex board;

[0036] S210: Alternately arranging the flexible board and the high-frequency unit dielectric structure according to any one of claims 1 to 9, and laminating the entire board, wherein the alternating arrangement structure includes at least one flexible board and at least one high-frequency unit dielectric structure;

[0037] S220: removing the high-frequency unit dielectric structure in the non-reserved area to form a rigid-flexible board.

[0038] It should be further explained that the high-frequency unit dielectric structure manufactured based on the above-mentioned method is alternately arranged with the flexible board to realize a modular manufacturing method. The surface of the high-frequency unit dielectric structure is flat, which provides good rigid support for the layout and pressing of the flexible board. The non-retained area is then removed along the half-groove. The non-retained area can be easily removed under the "isolation" of the release layer. The retained area forms the rigid area of ​​the rigid-flexible board. There is a large height difference between the flexible board layers, and the overall rigid-flexible board structure with a large height difference is formed.

[0039] Optionally, the removing of the high-frequency unit dielectric structure in the non-reserved area is performed by bending the entire plate along the slot body, breaking the high-frequency unit dielectric structure, and then removing the high-frequency unit dielectric structure in the non-reserved area.

[0040] It should be further explained that, based on the preparation of the ink layer and the release layer, the non-retention area can be easily removed.

[0041] The substrate of the present invention adopts a ceramic powder composite epoxy resin material, which has better processing performance and can be well combined with the ink layer and the flexible board layer to improve the interlayer bonding strength of the rigid area; the combination of the ink layer and the release layer enables the release layer to effectively adhere to the non-retention area during processing, and at the same time has a good release effect and is easy to peel off after processing. Even if it is a rigid-flexible board containing multiple flexible board parts, the high-frequency unit dielectric structure located in the inner layer can still be easily removed and manufactured; the combination of the ink layer and the release layer can effectively reduce the depth and width of the groove body at the junction of the retention area and the non-retention area, avoiding problems such as board surface depression during pressing; the modular combination of the flexible board layer and the high-frequency unit dielectric structure is adopted, that is, the flexible board layer is processed separately, the high-frequency unit dielectric structure module is processed separately, and then alternately arranged for overall processing, which can ensure that the processing of the flexible board layer circuit pattern is not affected by the high-frequency unit dielectric structure, and finally form a large-drop rigid-flexible board structure with a large drop between each flexible board. The manufacturing method is convenient, effectively improving the accuracy of circuit processing, and improving process capabilities and product reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 This is a production flow chart of a high-frequency unit dielectric structure of the present invention.

[0044] Figure 2 Schematic diagram of the structure of the trough body made of ceramic substrate.

[0045] Figure 3 Schematic diagram of the structure for making ink layer and release layer.

[0046] Figure 4 Schematic diagram of the high-frequency unit dielectric structure after laser ablation of the release layer.

[0047] Figure 5 Schematic diagram of the structure of the ink layer in the developed reserved area.

[0048] Figure 6 Schematic diagram of the high-frequency unit dielectric structure using prepreg to supplement the drop position.

[0049] Figure 7 The present invention is a flowchart for manufacturing a rigid-flexible board.

[0050] Figure 8 Schematic diagram of the structure for modular production of rigid-flex PCB.

[0051] Figure 9 It is a schematic diagram of the rigid-flex board structure after removing the non-retained area of ​​the high-frequency unit dielectric structure.

[0052] The following are the descriptions of the reference numerals:

[0053] 1-rigid-flexible board, 10-high-frequency unit dielectric structure, 100-ceramic substrate, 110-retained area; 120-non-retained area; 130-slot body, 140-ink layer, 150-release layer, 160-prepreg, 20-flexible board, 30-drop position. DETAILED DESCRIPTION

[0054] The following is a further description of specific embodiments of the present invention in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0055] See also Figures 1 to 6 In a first aspect, a method for manufacturing a high-frequency unit dielectric structure 10 is provided. The manufacturing steps are as follows: first, a ceramic substrate 100 is formed, and a groove body 130 is formed on the ceramic substrate. The high-frequency unit dielectric structure 10 is divided into a reserved area 110 and a non-reserved area 120 by the groove body 130; then, an ink layer 140 is formed on the ceramic substrate 100; a release layer 150 is formed on the ink layer 140, and the release layer 150 covers the non-reserved area 120 and the groove body 130; the release layer 150 is refined; the ink layer 140 is developed; and a prepreg 160 is used to fill the gap to form the high-frequency unit dielectric structure 10.

[0056] Please refer again Figure 2 The ceramic substrate 100 is a ceramic powder composite epoxy resin substrate; the groove body 130 is formed by laser engraving a half groove body, and the depth of a single groove body 130 does not exceed 1 / 3 of the thickness of the ceramic substrate 100. The groove body 130 is symmetrical with the ceramic substrate as the axis and is distributed on both sides of the ceramic substrate 100.

[0057] Please refer again Figure 3 The ink layer 140 is made by screen printing → pre-baking ink on the ceramic substrate 100, and the ink layer 140 is a black ink layer; the release layer 150 is made by pressing the release layer 150 on the ink layer 140 by lamination, and the release layer 150 is a PTFE or ETFE material release layer.

[0058] Please refer again Figure 4, the release layer 150 is finely trimmed, and the release layer 150 in the reserved area is trimmed by laser ablation.

[0059] Please refer again Figure 5 , the ink layer 140 is developed, and the development is to develop the ink layer 140 by adopting an exposure→development method.

[0060] Please refer again Figure 6 A prepreg 160 is used to fill the gap. The prepreg 160 is used to fill the gap formed on the ceramic substrate 100 between the ink layer 140 and the release layer 150. The prepreg 160 is a ceramic powder composite epoxy resin prepreg.

[0061] See also Figures 7 to 9 In a second aspect, a method for manufacturing a rigid-flexible board is provided, comprising the steps of: manufacturing a flexible board 20 required for laminating the rigid-flexible board 1; alternatingly arranging the flexible board 20 and the high-frequency unit dielectric structure 10 manufactured by the above method, and laminating the entire board, wherein the alternating arrangement structure includes at least one flexible board 20 and at least one high-frequency unit dielectric structure 10; and removing the high-frequency unit dielectric structure 10 in a non-retained area to form a rigid-flexible board 1.

[0062] Please refer again Figure 9 , removing the high-frequency unit dielectric structure 10 in the non-reserved area, bending the entire plate along the slot, breaking the high-frequency unit dielectric structure, and then removing the high-frequency unit dielectric structure in the non-reserved area.

[0063] After the high-frequency unit dielectric structure 10 in the non-reserved area is removed, a drop point 30 is formed at this location.

[0064] The reinforcement of the connection between the rigid plate and the flexible plate at the drop position can be achieved by using methods such as dispensing in the later process, which will not be explained in detail here.

[0065] The substrate of the present invention adopts a ceramic powder composite epoxy resin material, which has better processing performance and can be well combined with the ink layer and the flexible board layer to improve the interlayer bonding strength of the rigid area; the combination of the ink layer and the release layer enables the release layer to effectively adhere to the non-retention area during processing, and at the same time has a good release effect and is easy to peel off after processing. Even if it is a rigid-flexible board containing multiple flexible board parts, the high-frequency unit dielectric structure located in the inner layer can still be easily removed and manufactured; the combination of the ink layer and the release layer can effectively reduce the depth and width of the groove body at the junction of the retention area and the non-retention area, avoiding problems such as board surface depression during pressing; the modular combination of the flexible board layer and the high-frequency unit dielectric structure is adopted, that is, the flexible board layer is processed separately, the high-frequency unit dielectric structure module is processed separately, and then alternately arranged for overall processing, which can ensure that the processing of the flexible board layer circuit pattern is not affected by the high-frequency unit dielectric structure, and finally form a large-drop rigid-flexible board structure with a large drop between each flexible board. The manufacturing method is convenient, effectively improving the accuracy of circuit processing, and improving process capabilities and product reliability.

[0066] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. It is apparent to those skilled in the art that various changes, modifications, substitutions, and variations to these embodiments may be made without departing from the principles and spirit of the present invention, and these changes and modifications still fall within the scope of protection of the present invention.

[0067] In the description of the patent of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", "row", "column", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the patent of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation to the patent of the present invention.

[0068] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention patent, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0069] In invention patents, unless otherwise expressly specified or limited, terms such as "install," "connect," "connect," "fix," and "fixed" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components, unless otherwise expressly limited. A person of ordinary skill in the art can understand the specific meanings of the above terms in invention patents based on the specific circumstances.

[0070] In the present invention, unless otherwise expressly specified or limited, a first feature "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

Claims

1. A method for manufacturing a rigid-flex board, characterized in that: The following steps are involved: S200: manufacturing a flexible board required for laminating the rigid-flex board; S210: Alternately arranging the flexible board and the high-frequency unit dielectric structure, and laminating the entire board, wherein the alternately arranged structure includes at least one flexible board and at least one high-frequency unit dielectric structure; The steps of manufacturing the high-frequency unit dielectric structure include: S100: Taking a ceramic substrate, making a slot body on the ceramic substrate, wherein the high-frequency unit dielectric structure is divided into a reserved area and a non-reserved area by the slot body; S110: forming an ink layer on the ceramic substrate; S120: forming a release layer on the ink layer, wherein the release layer covers the non-retained area and the tank body; S130: fine-tune the release layer; the fine-tune is to trim the release layer in the reserved area by laser ablation; S140: developing the ink layer; S150: Filling the gap with a prepreg to form the high-frequency unit dielectric structure; S220: Removing the high-frequency unit dielectric structure in the non-reserved area to form a rigid-flexible board, wherein removing the high-frequency unit dielectric structure in the non-reserved area is performed by bending the entire board along the slot, breaking the high-frequency unit dielectric structure, and then removing the high-frequency unit dielectric structure in the non-reserved area.

2. The method for manufacturing a rigid-flex board according to claim 1, wherein: The ceramic substrate is a ceramic powder composite epoxy resin substrate.

3. The method for manufacturing a rigid-flex board according to claim 1, wherein: The trough body is formed by laser engraving to form a half trough body, and the trough bodies are symmetrically distributed on both sides of the ceramic substrate.

4. The method for manufacturing a rigid-flex board according to claim 1, characterized in that The ink layer is prepared by using a silk screen printing → pre-baking method to prepare ink on the ceramic substrate, and the ink layer is a black ink layer.

5. The method for manufacturing a rigid-flex board according to claim 1, wherein: The release layer is made by laminating the release layer on the ink layer using a laminating film, and the release layer is made of PTFE or ETFE material.

6. The method for manufacturing a rigid-flex board according to claim 1, wherein: The development is to develop the ink layer in a manner of exposure→development.

7. The method for manufacturing a rigid-flex board according to claim 1, wherein: The step of filling the gap with a prepreg is to fill the gap formed between the ink layer and the release layer on the ceramic substrate with the prepreg, and the prepreg is a ceramic powder composite epoxy resin prepreg.

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