Circuit board, metal trace manufacturing method and electronic device

Abstract

The embodiment of the present application provides a circuit board, a metal wiring manufacturing method and electronic equipment, through the following steps: after the first etching of the metal layer by using a photoresist layer, a process of heating the photoresist layer once is added, and then the second etching is performed to form the required metal wiring, so that the slope angle of the photoresist layer relative to the metal layer can be further reduced, so that when the second etching is performed on the metal layer, the slope angle of the formed metal wiring can be further reduced, and the covering performance of the subsequent film layer of the circuit board or the electronic equipment with the metal wiring is improved.

Description

Technical Field

[0001] This application relates to the field of electronic equipment manufacturing, and more specifically, to a circuit board, a method for manufacturing metal traces, and an electronic device. Background Technology

[0002] With the development of electronic device manufacturing technology, the requirements for miniaturization and integration of electronic devices are becoming increasingly stringent. In the manufacturing process of these devices, methods such as etching metal layers are commonly used to form precise metal layers or circuit boards. In some scenarios, the traces of electronic devices may be fabricated as a single unit or integrated with other components. For example, in display devices, additional film structures need to be fabricated on top of the metal trace layer of the driver backplane. However, the metal trace fabrication process in related technologies has certain shortcomings. Summary of the Invention

[0003] In order to make the formed metal traces more perfect, one purpose of this application is to provide a circuit board including metal traces, wherein the slope angle of the metal traces is less than 65 degrees.

[0004] By setting the slope angle of the metal trace within this range, the embodiments of this application can effectively avoid the breakage of other film layers located on the metal trace due to the excessive slope angle of the metal trace, thus effectively ensuring the coverage performance of subsequent film layers.

[0005] In some possible implementations, the longitudinal section of the side of the metal trace is stepped.

[0006] Another objective of this application is to provide a method for fabricating metal traces, used to prepare the metal traces in the circuit board provided in this application, the method comprising:

[0007] A metal layer is formed on the load-bearing layer;

[0008] A photoresist layer is formed on the metal layer, and the photoresist layer is patterned to expose at least a portion of the metal layer.

[0009] The exposed metal layer is etched for the first time, and the depth of the first etching is less than the thickness of the metal layer;

[0010] The photoresist layer is heated to reduce the slope angle of the photoresist layer relative to the metal layer;

[0011] The exposed metal layer is then etched a second time to form metal traces.

[0012] Thus, the first etching is performed first, forming a small step in the metal layer. After the photoresist layer is converted to a highly elastic state, it can spread out to both sides along this step, thereby guiding the flow direction of the photoresist layer and ensuring the positional accuracy when etching to form metal traces later.

[0013] In some possible implementations, the step of heating the photoresist layer includes:

[0014] The photoresist layer is heated to a temperature not lower than its glass transition temperature, causing it to transform into a highly elastic state. Thus, after the photoresist layer transforms into a highly elastic state, it exhibits certain viscous flow properties, and its slope angle relative to the metal layer naturally decreases during flow.

[0015] In some possible implementations, the photoresist layer is heated for at least 60 seconds. This ensures that the photoresist layer can be fully converted to a highly elastic state.

[0016] In some possible implementations, prior to the step of performing a second etching on the exposed metal layer, the method further includes:

[0017] The photoresist layer is cooled to convert it into a glassy state.

[0018] In some possible implementations, the step of heating the photoresist layer includes:

[0019] While keeping the side of the photoresist layer closest to the metal layer facing downwards, the photoresist layer is heated. In this way, after the photoresist layer transforms into a highly elastic state, it can spread downwards and flow to both sides under its own gravity, thereby reducing the slope angle of the photoresist layer relative to the metal layer.

[0020] In some possible implementations, the step of heating the photoresist layer includes:

[0021] The photoresist layer is heated from the side closest to the metal layer using a heating plate. This ensures that the side of the photoresist layer closest to the metal layer converts to a highly elastic state upon heating, which facilitates the flow of the photoresist layer.

[0022] In some possible implementations, the ratio of the depth of the first etching to the depth of the second etching is 1 / 3 to 1.

[0023] In some possible implementations, the first etching and the second etching may employ plasma etching.

[0024] Another objective of this application is to provide an electronic device, which includes the circuit board provided in this application or the metal traces prepared using the metal trace fabrication method provided in this embodiment.

[0025] Compared to existing technologies, the circuit board, metal trace fabrication method, and electronic device provided in this embodiment, by performing a first etching of the metal layer using a photoresist layer, adds a heating step to the photoresist layer before performing a second etching to form the required metal trace. This further reduces the slope angle of the photoresist layer relative to the metal layer, thereby further reducing the slope angle of the formed metal trace during the second etching of the metal layer, and thus improving the coverage performance of subsequent film layers on the circuit board or electronic device with the metal trace. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is one of the process diagrams for manufacturing metal traces in existing technologies;

[0028] Figure 2 The second schematic diagram illustrates the process of manufacturing metal traces using existing technologies.

[0029] Figure 3 This is a schematic diagram of the structure of the metal traces provided in the embodiments of this application;

[0030] Figure 4 A flowchart illustrating the steps of a metal trace fabrication method provided in this application embodiment;

[0031] Figure 5 One of the schematic diagrams illustrating the metal trace fabrication process provided in the embodiments of this application;

[0032] Figure 6 This is a second schematic diagram illustrating the metal trace fabrication process provided in an embodiment of this application.

[0033] Figure 7 The third schematic diagram of the metal trace fabrication process provided in the embodiments of this application;

[0034] Figure 8 Fourth schematic diagram of the metal trace fabrication process provided in the embodiments of this application;

[0035] Figure 9This is the fifth schematic diagram of the metal trace fabrication process provided in the embodiments of this application. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0038] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0039] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0040] It should be noted that, where there is no conflict, different features in the embodiments of this application can be combined with each other.

[0041] Through long-term research, the inventors discovered that in some existing metal trace fabrication methods, a patterned photoresist is first formed on a metal layer, and then the metal layer is etched to remove the portions of the metal layer not covered by the photoresist. For example, please refer to... Figure 1 In existing metal trace fabrication methods, a patterned photoresist layer 300 is typically first applied to the metal layer 200. Then, please refer to... Figure 2 The metal layer 200 is directly etched to remove the portion of the metal layer 200 not covered by the photoresist layer 300, in order to form the required metal traces.

[0042] In this scenario, the taper angle of the patterned photoresist layer 300 relative to the metal layer 200 directly affects the taper angle of the etched metal traces. However, due to current limitations in photoresist exposure and development processes, it is difficult to further reduce the taper angle of the patterned photoresist, which in turn makes it difficult to further reduce the taper angle of the etched metal traces.

[0043] In view of this, this embodiment provides a solution that can further reduce the slope angle of metal traces during the etching process. The solution provided in this embodiment will be described in detail below.

[0044] This embodiment provides a circuit board, which includes metal traces that can be formed on a carrier layer, and the slope angle of the metal traces is less than 65 degrees.

[0045] By setting the slope angle of the metal trace within this range, the embodiments of this application can effectively avoid problems such as breakage of other film layers located on the metal trace due to the excessive slope angle of the metal trace, thus effectively ensuring the coverage performance of subsequent film layers.

[0046] Optionally, the longitudinal section of the side of the metal trace is stepped, as shown in the example. Figure 3 It is understandable that the sides of a metal trace are the surfaces at both ends of the trace. This design allows for a smaller slope angle in the metal trace while maintaining its width within a certain range, effectively preventing problems such as breakage and delamination in subsequent film layers located above the metal trace.

[0047] Please see Figure 4 , Figure 4 This is a flowchart illustrating the steps of a method for fabricating metal traces according to this embodiment. This method is used to form the aforementioned metal traces. The steps of this method will be explained in detail below.

[0048] Step S110: A metal layer 200 is formed on the carrier layer 100.

[0049] Please refer to Figure 5 In this embodiment, the metal layer 200 can be formed on a carrier layer 100 first. Exemplarily, the metal layer can be formed by, but is not limited to, sputtering or other methods. In one possible implementation, the material of the metal layer 200 can be a metallic material with good electrical conductivity. The carrier layer 100 can include any film layer suitable for carrying metal traces, such as an insulating layer or dielectric layer of a drive backplane, an insulating layer or dielectric layer of a touch module, etc., but is not limited to these.

[0050] In step S120, a photoresist layer 300 is formed on the metal layer 200, and the photoresist layer 300 is patterned so that the photoresist layer 300 exposes at least a portion of the metal layer 200.

[0051] Please refer to Figure 6 In this embodiment, photoresist can be coated on the metal layer 200, and then some of the photoresist can be removed by exposure and development to expose the location of the metal layer 200 that needs to be etched away.

[0052] In some possible implementations, after the photoresist layer 300 is patterned, the area of ​​the metal layer 200 it covers can be slightly smaller than the linewidth of the final required metal trace.

[0053] Step S130: The exposed metal layer 200 is etched for the first time. The depth of the first etching is less than the thickness of the metal layer 200, so that the metal layer 200 is not etched through during the first etching process.

[0054] Please refer to Figure 7 Compared to the traditional method of directly forming metal traces through one-time etching, in this embodiment, a first etching can be performed first, and the thickness of the first etching can be controlled to not exceed the total thickness of the metal layer 200 by setting etching time, etching rate, etc.

[0055] Step S140: The photoresist layer 300 is heated to reduce the slope angle of the photoresist layer 300 relative to the metal layer 200.

[0056] Specifically, in one possible implementation, please refer to Figure 8 In this embodiment, after the first etching is completed, the entire workpiece, including the carrier layer 100, the metal layer 200, and the patterned photoresist layer 300, can be transported to the baking chamber for baking. The photoresist layer 300 is heated at a temperature not lower than the glass transition temperature of the photoresist layer 300, so that the photoresist layer 300 changes from a glassy state to a high-elastic state.

[0057] Compared to the case where the photoresist layer 300 is in a glassy state, after the photoresist layer 300 is converted to a highly elastic state, it has certain viscous flow properties. During the flow process, its slope angle relative to the metal layer 200 naturally decreases.

[0058] In this embodiment, since the first etching is performed first, the metal layer 200 forms a small step. Thus, after the photoresist layer 300 is converted to a highly elastic state, it can spread out to both sides along the step, thereby guiding the flow direction of the photoresist layer 300 and ensuring the positional accuracy when etching to form metal traces.

[0059] Step S150: The exposed metal layer 200 is etched a second time to form metal traces on the carrier layer 100.

[0060] Please refer to Figure 9 In one possible implementation, in this embodiment, after heating the photoresist layer 300, the metal layer 200 can be etched a second time. The second etching can completely etch away the metal layer 200 that is not covered by the photoresist layer 300, forming a metal trace.

[0061] After etching is completed, the photoresist layer 300 can be removed to form a layer as shown in the image. Figure 3 The metal traces shown.

[0062] Based on the above design, in the metal trace fabrication method provided in this embodiment, after the first etching of the metal layer 200, an additional heating step is added to the photoresist layer 300. This can further reduce the slope angle of the photoresist layer 300 relative to the metal layer 200. As a result, when the metal layer 200 is etched for the second time, the slope angle of the formed metal trace can be further reduced, thereby improving the coverage performance of subsequent film layers and avoiding adverse phenomena such as separation of subsequent film layers from metal traces.

[0063] It is understood that after step S150, all the photoresist layers 300 covering the metal traces can be removed by re-exposure and development to expose the metal traces.

[0064] In some possible implementations, before performing the second etching on the exposed metal layer 200 in step S150, the photoresist layer 300 may be cooled to convert it into a glassy state. Then, the exposed metal layer 200 is etched a second time.

[0065] In some possible implementations, the photoresist layer 300 is heated for no less than 60 seconds. This ensures that the photoresist layer 300 can be fully converted to a highly elastic state.

[0066] In some possible implementations, when heating the photoresist layer 300 in step S140, the photoresist layer 300 can be heated while keeping the side of the photoresist layer 300 closest to the metal layer 200 facing downwards (e.g., towards the ground). In this way, after the photoresist layer 300 transitions to a highly elastic state, it can spread downwards and flow to both sides under its own gravity, thereby reducing the slope angle of the photoresist layer 300 relative to the metal layer 200.

[0067] In some possible implementations, when heating the photoresist layer 300 in step S140, the photoresist layer 300 can be heated from the side of the photoresist layer 300 closest to the metal layer 200 using a heating plate. For example, the workpiece to be processed can be placed on the heating plate with the side containing the photoresist away from the heating plate, and then heated using the heating plate. In this way, it can be preferentially ensured that the side of the photoresist layer 300 closest to the metal layer 200 converts to a highly elastic state after heating, which is beneficial to the flow of the photoresist layer 300.

[0068] It is understandable that if the depth of the first etching is too large, the proportion of steps with large slope angles formed during the first etching will be too large, which may not achieve the effect of significantly reducing the overall slope angle of the metal trace; if the depth of the first etching is too small, the highly elastic photoresist layer 300 cannot be smoothly guided to flow to both sides. Therefore, in some possible implementations, based on experimental data verification, the ratio of the depth of the first etching of the metal layer 200 to the depth of the second etching is preferably 1 / 3 to 1.

[0069] In some possible implementations, both the first etching and the second etching can be performed using plasma etching.

[0070] In some possible implementations, a dedicated baking chamber can be used to heat the photoresist layer 300. For example, the etching process for the metal layer 200 is typically performed in an etching process chamber. In this embodiment, a baking chamber can be connected to the etching process chamber via a transfer chamber. After the first etching is completed, the entire workpiece is transported to the baking chamber for heating via the transfer chamber. After heating is completed, the workpiece is then transported back to the etching process chamber via the transfer chamber to perform the second etching.

[0071] Based on the foregoing and the same inventive concept, this embodiment also provides an electronic device. The electronic device may include the circuit board provided in this embodiment or metal traces prepared using the metal trace fabrication method provided in this embodiment. As an example, the electronic device may be a display device, wherein the circuit board may be a driving backplane, touch module, or similar component of the display device.

[0072] In summary, the circuit board, metal trace fabrication method, and electronic device provided in this embodiment, by performing a first etching of the metal layer using a photoresist layer, adds a heating step to the photoresist layer, followed by a second etching of the metal layer after heating to form the desired metal trace. This further reduces the slope angle of the photoresist layer relative to the metal layer, thereby further reducing the slope angle of the formed metal trace during the second etching of the metal layer, and thus improving the coverage performance of subsequent film layers on the circuit board or electronic device with the metal trace.

[0073] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for manufacturing metal traces, characterized in that, The method for manufacturing the metal trace includes: A metal layer is formed on the load-bearing layer; A photoresist layer is formed on the metal layer, and the photoresist layer is patterned to expose at least a portion of the metal layer. The exposed metal layer is etched for the first time, and the depth of the first etching is less than the thickness of the metal layer; With the side of the photoresist layer closest to the metal layer facing down, the photoresist layer is heated from the side closest to the metal layer using a heating plate to reduce the slope angle of the photoresist layer relative to the metal layer; The exposed metal layer is then etched a second time to form metal traces.

2. The method for manufacturing metal traces according to claim 1, characterized in that, The step of heating the photoresist layer includes: The photoresist layer is heated at a temperature not lower than the glass transition temperature of the photoresist layer, so that the photoresist layer is transformed into a highly elastic state.

3. The method for manufacturing metal traces according to claim 2, characterized in that, The photoresist layer is heated for no less than 60 seconds.

4. The method for manufacturing metal traces according to any one of claims 1-3, characterized in that, Prior to the step of performing a second etching on the exposed metal layer, the method further includes: The photoresist layer is cooled to convert it into a glassy state.

5. The method for manufacturing metal traces according to claim 1, characterized in that, The ratio of the depth of the first etching to the depth of the second etching is 1 / 3 to 1.

6. The method for manufacturing metal traces according to claim 1, characterized in that, The first and second etching processes employ plasma etching.

7. A circuit board, characterized in that, The circuit board includes metal traces made by the method of any one of claims 1-6, wherein the slope angle of the metal traces is less than 65 degrees; the longitudinal section of the side of the metal traces is stepped, and the slope angle of the step away from the bearing layer is greater than the slope angle of the step close to the bearing layer.

8. An electronic device, characterized in that, The electronic device includes the circuit board as described in claim 7 or the metal traces prepared by the metal trace fabrication method as described in any one of claims 2-6.

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