Circuit board opening method and circuit board
By using first and second elastic layers with higher fluidity than adhesive layers to fill gaps during the circuit board opening process, the problem of adhesive overflow was solved, the process was simplified and costs were reduced, and the reliability of electrical connections was ensured.
Patent Information
- Application Number
- CN202110937022.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-08-16
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2041-08-16
AI Technical Summary
Existing circuit board opening processes suffer from adhesive overflow issues, leading to unreliable electrical connections and increasing complexity and costs.
The first and second elastic layers have higher fluidity than the adhesive layer during the pressing process, filling gaps and blocking the flow of the adhesive layer, avoiding adhesive overflow, simplifying the process and eliminating the need for a peelable adhesive step.
It effectively prevents adhesive overflow, simplifies the process, reduces costs, and ensures reliable electrical connections.
Smart Images
Figure CN115707200B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of circuit boards, and more particularly to a method for opening a circuit board and the circuit board itself. Background Technology
[0002] The manufacturing process of circuit boards typically involves a capping step to expose the internal circuitry layers to suit the intended operating environment. Existing capping processes fall into two categories: the first involves pre-applying peelable adhesive to the inner circuitry layers, followed by a layering step, and then capping the areas corresponding to the peelable adhesive; the second involves pre-applying no adhesive layer to the circuitry substrate, followed by a layering step, and then capping the areas corresponding to the peelable adhesive. The first method is more complex and increases the cost of the peelable layer; the second method cannot control adhesive overflow, which can cause the adhesive to overflow towards the capping area, potentially making it impossible to peel off the cap, or even overflowing onto the circuitry layers or solder pads, leading to unreliable electrical connections. Summary of the Invention
[0003] In view of this, it is necessary to provide a method for opening circuit boards that prevents adhesive overflow and simplifies the process.
[0004] A method for opening a circuit board includes the following steps: providing a first circuit substrate, including a first elastic layer and a first circuit layer stacked thereon, at least a portion of the first elastic layer being exposed on the first circuit layer, the first circuit substrate including an opening area and a main body area connected to the opening area, the opening area including at least a portion of the first circuit layer and the first elastic layer exposed on the first circuit layer; providing a second circuit substrate, including a second elastic layer and an adhesive layer, a portion of the surface of the second elastic layer being exposed on the adhesive layer; stacking the second circuit substrate on the surface of the first circuit substrate, the adhesive layer facing the first circuit substrate and bonded to the main body area, the second elastic layer exposed on the adhesive layer being spaced apart from the first circuit substrate and corresponding to the opening area; heating and pressing the first circuit substrate and the second circuit substrate, the first elastic layer and the second elastic layer deforming and flowing toward the gap between the first circuit layers; and removing the area of the second circuit substrate corresponding to the opening area to expose the opening area, thereby obtaining the circuit board.
[0005] In some embodiments, at the temperature during pressing, the fluidity of the adhesive layer is lower than that of the first elastic layer and the second elastic layer.
[0006] In some embodiments, the materials of the first elastic layer and the second elastic layer are selected from styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, and thermoplastic polyurethane elastomer rubber, respectively.
[0007] In some embodiments, the second circuit board further includes a second circuit layer located on the surface of the second elastic layer opposite to the first circuit board.
[0008] In some embodiments, the first circuit board further includes a first dielectric layer located on the surface of the first elastic layer opposite to the first circuit layer.
[0009] The second circuit board further includes a second dielectric layer, which is located on the surface of the second elastic layer opposite to the first circuit board.
[0010] A circuit board includes a first circuit board and a second circuit board stacked thereon; the first circuit board includes a main body region and a cover region connected to each other, the main body region being connected to the second circuit board, and the cover region being exposed to the second circuit board; the first circuit board includes a first elastic layer and a first circuit layer stacked thereon, the first circuit layer being located on the side of the first elastic layer facing the second circuit board, and the second circuit board includes a second elastic layer and an adhesive layer stacked thereon, the adhesive layer being located on the surface of the second elastic layer facing the first circuit board, the adhesive layer bonding the second elastic layer and the main body region.
[0011] In some embodiments, the materials of the first elastic layer and the second elastic layer may be selected from styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, and thermoplastic polyurethane elastomer rubber, respectively.
[0012] In some embodiments, the first elastic layer fills the gaps in the first circuit layer on the side facing the first circuit layer.
[0013] In some embodiments, the second circuit board further includes a second circuit layer located on the surface of the second elastic layer opposite to the first circuit board.
[0014] In some embodiments, the first circuit board further includes a first dielectric layer located on the surface of the first elastic layer opposite to the first circuit layer; the second circuit board further includes a second dielectric layer located on the surface of the second elastic layer opposite to the first circuit board.
[0015] The circuit board opening method provided in this application includes a first elastic layer and a second elastic layer. During the lamination process, the first and second elastic layers, being fluid, flow without cross-linking, facilitating subsequent opening. Furthermore, the second elastic layer flows and fills the gap between the opening area and the main body area, preventing the adhesive from deforming and flowing towards the opening area, thus preventing adhesive overflow and ensuring reliable electrical connections on the circuit board. This acts as an adhesive barrier, eliminating the need for adhesive removal (removing excess adhesive). This opening method also replaces the existing process of first applying peelable adhesive and then opening the board, simplifying the process (eliminating the step of applying peelable adhesive) and saving the cost of using peelable adhesive. Attached Figure Description
[0016] Figure 1 This is a cross-sectional schematic diagram of the first circuit board provided in an embodiment of this application.
[0017] Figure 2 This is a cross-sectional schematic diagram of the second circuit board provided in an embodiment of this application.
[0018] Figure 3 To be Figure 1 The first circuit board and Figure 2 A schematic cross-sectional view of the second circuit board after it has been stacked.
[0019] Figure 4 To be Figure 3 The diagram shows a cross-sectional view of the first circuit board and the second circuit board after they have been laminated together.
[0020] Figure 5 For opening and removing Figure 4 The second circuit board in the diagram corresponds to the area of the open cover area, forming a cross-sectional schematic diagram of the circuit board.
[0021] Explanation of main component symbols
[0022]
[0023] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation
[0024] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. Many specific details are set forth in the following description to provide a thorough understanding of this application; the described embodiments are merely some, not all, of the embodiments described in this application.
[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The term "and / or" as used herein includes all and any combination of one or more of the associated listed items.
[0026] In the various embodiments of this application, for ease of description and not limitation, the term "connection" used in the patent application specification and claims is not limited to physical or mechanical connections, whether direct or indirect. Terms such as "upper," "lower," "above," "below," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship also changes accordingly.
[0027] Please see Figures 1 to 5 This application provides a method for opening a circuit board 100, including the following steps:
[0028] Step S1: Please refer to Figure 1 A first circuit board 10 is provided, including a first elastic layer 11 and a first circuit layer 13 stacked thereon, at least a portion of the first elastic layer 11 being exposed to the first circuit layer 13, the first circuit board 10 including an open cover region II and a main body region I connected to the open cover region II, the open cover region II including at least a portion of the first circuit layer 13 and the first elastic layer 11 exposed to the first circuit layer 13.
[0029] The first circuit board 10 can be a single-layer circuit board or a multi-layer circuit board. In this embodiment, the first circuit board 10 is a double-layer circuit board.
[0030] Understandably, there are gaps between the first line layers 13.
[0031] In some embodiments, the first circuit board 10 may further include a first dielectric layer 15, which is located in and stacked with the first elastic layer 11. In this embodiment, the first dielectric layer 15 has one layer, the first elastic layer 11 has two layers, located on opposite surfaces of the first dielectric layer 15, and the first circuit layer 13 is located on the surface of the first elastic layer 11 facing away from the first dielectric layer 15.
[0032] Step S2: Please refer to Figure 2 A second circuit board 20 is provided, the second circuit board 20 includes a second elastic layer 21 and an adhesive layer 27, a portion of the surface of the second elastic layer 21 is exposed to the adhesive layer 27.
[0033] At least a portion of the surface of the second elastic layer 21 is located on the outer surface of the second circuit substrate 20, so as to facilitate subsequent connection of the second elastic layer 21 to the surface of the first circuit substrate 10.
[0034] The adhesive layer 27 is disposed on a portion of the surface of the second elastic layer 21. The surface of the second elastic layer 21 without the adhesive layer 27 corresponds to the opening area II, so as to prevent the adhesive layer 27 from being located in the opening area II and adhering to the first circuit layer 13 located in the opening area II.
[0035] The second circuit board 20 may further include a second circuit layer 23 or a copper layer for forming the second circuit layer 23, wherein the second circuit layer 23 or the copper layer is located on the surface of the second elastic layer 21 opposite to the adhesive layer 27.
[0036] In some embodiments, the second circuit board 20 further includes a second dielectric layer 25, which is located between the second elastic layer 21 and the second circuit layer 23 or the second circuit layer 23.
[0037] In this embodiment, the second elastic layer 21 has two layers, the second dielectric layer 25 is located between the two layers of the second elastic layer 21, and the second circuit layer 23 is located on the surface of one of the second elastic layers 21 that is away from the second dielectric layer 25.
[0038] Both the first elastic layer 11 and the second elastic layer 21 are made of elastomers, which are a type of viscoelastic polymer, and can be thermosetting polymers or thermoplastic polymers. Thermosetting polymers can be vulcanized to increase the elasticity of the material; thermoplastic polymers can be materials such as polystyrene and polyurethane, including but not limited to styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), and thermoplastic polyurethane elastomer rubber (TPU).
[0039] The elastomer is solid at room temperature. When heated to its inherent glass transition temperature (Tg), the elastomer becomes highly elastic and exhibits a certain degree of fluidity. During cooling, the elastomer gradually returns to a solid state. For example, the glass transition temperatures (Tg) of styrene-butadiene-styrene block copolymers SBS1301, SBS1401, and SBS4303 are 84℃, 82℃, and 94℃, respectively.
[0040] Step S3: Please refer to Figure 3The second circuit board 20 is stacked on the surface of the first circuit board 10, the adhesive layer 27 faces the first circuit board 10 and is bonded to the main body area I, and the second elastic layer 21 exposed to the adhesive layer 27 is spaced apart from the first circuit board 10 and corresponds to the opening area II.
[0041] In this embodiment, the second circuit board 20 is stacked on both opposite surfaces of the first circuit board 10.
[0042] Step S4: Please refer to Figure 4 The first circuit substrate 10 and the second circuit substrate 20 are heated and pressed together, and the first elastic layer 11 and the second elastic layer 21 deform and flow toward the gap between the first circuit layers 13.
[0043] Specifically, the material is first heated to a temperature exceeding the glass transition temperature Tg of the first elastic layer 11 and the second elastic layer 21, but below the temperature at which the adhesive layer 27 has the maximum viscosity, and then pressed together. This causes the material of the first elastic layer 11 and the second elastic layer 21 to become highly elastic. That is, at the pressing temperature, the fluidity of the first elastic layer 11 and the second elastic layer 21 is greater than that of the adhesive layer 27. At this time, the first elastic layer 11 and the second elastic layer 21 preferentially flow to fill the gaps between the first circuit layers 13 and block the adhesive layer 27, thereby playing a role in preventing adhesive adhesion. In one specific embodiment, the glass transition temperature (Tg) of the first elastic layer 11 and the second elastic layer 21 is 101°C, and the temperature at which the adhesive layer 27 has the lowest viscosity (i.e., the best fluidity) is 140°C. Therefore, the pressing temperature can be between 101°C and 120°C. Pressing is performed before the temperature reaches the minimum viscosity of the adhesive layer 27 (20°C-30°C) to prevent excessively high temperatures and excessive fluidity of the adhesive layer 27, which would render the first elastic layer 11 and the second elastic layer 21 ineffective in their adhesive-resistant function. In other embodiments, the specific pressing temperature can be selected based on the specific materials of the elastomer and the adhesive layer 27.
[0044] The adhesive layer 27 corresponds to the main body region I. The openable region II does not have the adhesive layer 27. The adhesive layer 27 bonds the first circuit layer 13 located in the main body region I and the second elastic layer 21 of the second circuit substrate 20. During the pressing process, the first elastic layer 11 and the second elastic layer 21 flow but do not crosslink, which facilitates subsequent opening. The second elastic layer 21 deforms at high temperature and fills the step difference between the openable region II and the main body region I, preventing the adhesive from flowing towards the openable region II due to deformation, preventing the adhesive layer 27 from overflowing, and playing a role in preventing adhesive from overflowing.
[0045] Step S5: Please refer to Figure 5Remove the area of the second circuit board 20 corresponding to the opening area II to expose the opening area II, so as to obtain the circuit board 100.
[0046] Along the predetermined opening area II, the second circuit board 20 corresponding to the opening area II is removed, while the area of the second circuit board 20 corresponding to the main body area I is retained. Due to the inherent properties of the materials between the first elastic layer 11 and the second elastic layer 21, they exhibit fluidity at high temperatures. After flowing, they come into contact with each other but do not cross-link, making them easily separable during the opening step.
[0047] After the portion of the second circuit board 20 corresponding to the opening area II is removed, the opening area II is exposed. During the pressing process, the first elastic layer 11 flows toward the gap of the first circuit layer 13, and the side of the first elastic layer 11 facing the first circuit layer 13 fills the gap of the first circuit layer 13.
[0048] Please refer to it again. Figure 5 This application also provides a circuit board 100, which includes a first circuit board 10 and a second circuit board 20, wherein the first circuit board 10 and the second circuit board 20 are stacked.
[0049] The first circuit board 10 includes a main body region I and an open cover region II connected to each other. The main body region I is connected to the second circuit board 20, and the open cover region II is exposed to the second circuit board 20.
[0050] The first circuit board 10 includes a first elastic layer 11 and a first circuit layer 13 stacked together. The first circuit layer 13 is located on the side of the first elastic layer 11 facing the second circuit board 20, and a portion of the surface of the first elastic layer 11 is exposed to the first circuit layer 13. At least a portion of the first circuit layer 13 and at least a portion of the first elastic layer 11 exposed to the first circuit layer 13 are located in the open cover area II.
[0051] The first circuit board 10 may further include a first dielectric layer 15, which is located in the first elastic layer 11 and stacked with the first elastic layer 11.
[0052] The second circuit board 20 includes a stacked adhesive layer 27 and a second elastic layer 21. The adhesive layer 27 is located on the surface of the second elastic layer 21 facing the first circuit board 10, and the adhesive layer 27 bonds the second elastic layer 21 and the main body area I. In the circuit board 100 manufactured using the above-described opening method, the adhesive layer 27 will not overflow into the opening area II.
[0053] The second circuit board 20 further includes a second circuit layer 23, which is located on the side of the second elastic layer 21 away from the first circuit board 10.
[0054] In some embodiments, the second circuit board 20 may further include a second dielectric layer 25, which is located between the second elastic layer 21 and the second circuit layer 23.
[0055] The circuit board 100 opening method provided in this application includes a first elastic layer 11 and a second elastic layer 21. During the pressing process, the first elastic layer 11 and the second elastic layer 21, which are fluid, flow but do not cross-link, facilitating subsequent opening. Furthermore, the second elastic layer 21 flows and fills the gap between the opening area II and the main body area I, preventing the adhesive from deforming and flowing towards the opening area II, thus preventing adhesive overflow from the adhesive layer 27 and ensuring reliable electrical connections of the circuit board 100. This serves as an adhesive barrier, eliminating the need for adhesive removal (removal of excess adhesive). The above opening method also replaces the existing process of first applying peelable adhesive and then opening the board, simplifying the process (eliminating the step of applying peelable adhesive) and saving the cost of using peelable adhesive.
[0056] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application should not depart from the spirit and scope of the technical solutions of this application.
Claims
1. A method for opening a circuit board, characterized in that, Includes the following steps: A first circuit board is provided, including a first elastic layer and a first circuit layer stacked thereon, at least a portion of the first elastic layer being exposed to the first circuit layer, the first circuit board including an open cover region and a body region connected to the open cover region, the open cover region including at least a portion of the first circuit layer and the first elastic layer exposed to the first circuit layer. A second circuit board is provided, including a second elastic layer and an adhesive layer, wherein a portion of the surface of the second elastic layer is exposed to the adhesive layer; The second circuit board is stacked on the surface of the first circuit board, the adhesive layer faces the first circuit board and is bonded to the main body area, and the second elastic layer exposed to the adhesive layer is spaced apart from the first circuit board and corresponds to the opening area. The first circuit substrate and the second circuit substrate are heated and pressed together. The first elastic layer and the second elastic layer deform and flow toward the gap between the first circuit layers. At the temperature during pressing, the fluidity of the adhesive layer is lower than that of the first elastic layer and the second elastic layer. During the pressing process, the fluid first elastic layer and the second elastic layer flow but do not crosslink. as well as Remove the area of the second circuit board corresponding to the opening area to expose the opening area, thereby obtaining the circuit board.
2. The circuit board opening method according to claim 1, characterized in that, The materials of the first elastic layer and the second elastic layer are respectively selected from styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, and thermoplastic polyurethane elastomer rubber.
3. The circuit board opening method according to claim 1, characterized in that, The second circuit board further includes a second circuit layer, which is located on the surface of the second elastic layer opposite to the first circuit board.
4. The circuit board opening method according to claim 1, characterized in that, The first circuit board further includes a first dielectric layer, which is located on the surface of the first elastic layer opposite to the first circuit layer. The second circuit board further includes a second dielectric layer, which is located on the surface of the second elastic layer opposite to the first circuit board.
5. A circuit board manufactured using the circuit board opening method according to any one of claims 1-4, characterized in that, The device includes a first circuit board and a second circuit board stacked together. The first circuit board includes a main body region and a cover region connected to each other. The main body region is connected to the second circuit board, and the cover region is exposed to the second circuit board. The first circuit board includes a first elastic layer and a first circuit layer stacked together. The first circuit layer is located on the side of the first elastic layer facing the second circuit board. The second circuit board includes a second elastic layer and an adhesive layer stacked together. The adhesive layer is located on the surface of the second elastic layer facing the first circuit board, and the adhesive layer bonds the second elastic layer and the main body region.
6. The circuit board according to claim 5, characterized in that, The materials of the first elastic layer and the second elastic layer can be selected from styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, and thermoplastic polyurethane elastomer rubber, respectively.
7. The circuit board according to claim 5, characterized in that, The first elastic layer fills the gaps in the first circuit layer on the side facing the first circuit layer.
8. The circuit board according to claim 5, characterized in that, The second circuit board further includes a second circuit layer, which is located on the surface of the second elastic layer opposite to the first circuit board.
9. The circuit board according to claim 5, characterized in that, The first circuit board further includes a first dielectric layer located on the surface of the first elastic layer opposite to the first circuit layer; the second circuit board further includes a second dielectric layer located on the surface of the second elastic layer opposite to the first circuit board.
Citation Information
Patent Citations
Rigid-flex circuit substrate, rigid-flex circuit board and manufacturing methods
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