A mobile phone camera PCB substrate for improving chip tilt

Abstract

The utility model relates to camera substrate technical field, concretely relates to a mobile phone camera PCB substrate of improvement chip tilt, including substrate, the substrate includes surface layer and sets up the anti -soldering ink layer of surface layer, is equipped with copper foil wiring dense area and copper foil wiring empty scattering area on the surface layer, the thickness of anti -soldering ink layer is uniform and consistent on copper foil wiring dense area and copper foil wiring empty scattering area.

Description

Technical Field

[0001] This utility model relates to the field of camera substrate technology, specifically to a mobile phone camera PCB substrate that improves DA Tilt. Background Technology

[0002] Currently, mainstream mobile phone camera PCB substrates use solder resist ink to cover the surface layer of the PCB. However, due to the distribution of sensor chip pins, some areas have dense copper foil traces, while others have sparse or no copper foil traces, resulting in large areas of copper foil. Due to the flow characteristics of the ink, after the PCB is coated with solder resist ink, in areas with dense copper foil traces, the solder resist ink seeps into the grooves between the copper foil traces, resulting in thinner ink in these areas, causing the PCB to sag. Conversely, in areas with sparse or no copper foil traces, the ink is relatively thicker due to fewer grooves or larger copper foil areas, making the PCB higher. This results in an uneven PCB where the copper foil traces are densely packed and relatively higher in areas with sparse or no copper foil traces. After mounting the photosensitive chip, DA Tilt (chip tilt) occurs, causing a decrease in camera resolution and exceeding specifications.

[0003] Therefore, there is an urgent need for a mobile phone camera PCB substrate with improved DA Tilt, which can enhance the flatness of the substrate. Utility Model Content

[0004] The technical problem solved by this utility model is to provide a mobile phone camera PCB substrate that improves DA Tilt and can enhance the flatness of the substrate.

[0005] The basic solution provided by this utility model is: a mobile phone camera PCB substrate with improved DA Tilt, comprising a substrate, the substrate including a surface layer and a solder resist ink layer disposed on the surface layer; the surface layer is provided with a dense copper foil trace area and a loose copper foil trace area; the solder resist ink layer has a uniform thickness in the dense copper foil trace area and the loose copper foil trace area.

[0006] The principle and advantages of this utility model are as follows: In this solution, by setting solder resist ink layers in both the dense and sparse areas of copper foil traces on the surface layer, and with corresponding uniform thickness, the ink thickness is the same in areas with dense copper foil traces and areas with sparse or no copper foil traces, thus improving the situation where ink seeps into the trace grooves and causes unevenness on the PCB.

[0007] Compared to existing PCB substrates that use solder resist ink to cover the surface but do not fully consider the uneven thickness of the solder resist ink due to its fluidity, resulting in uneven PCB surface, DA tilt after chip mounting, and unstable DA temporary padding process, this solution improves substrate flatness by maintaining a uniform thickness of the solder resist ink layer in both dense and sparse copper trace areas.

[0008] At the same time, it significantly reduces the impact of the substrate on DA tilt during DA, which can improve DA tilt by about 15um. Poor DA tilt can lead to a decrease in camera resolution, exceeding the resolution specification requirements. If the resolution does not meet the requirements during production, the equipment will discard the material, reducing the product yield and increasing the cost. This effectively improves the SFR focusing production yield of mobile phone modules and reduces production costs.

[0009] Furthermore, the thickness of the solder resist ink layer is between 15µm and 35µm.

[0010] Furthermore, a groove is provided between each copper foil trace in the dense copper foil trace area, and a solder resist ink layer is also provided on the groove.

[0011] Furthermore, the solder resist ink layer is set through an ink leveling process, which involves printing the solder resist ink onto the surface layer to form a solder resist ink layer, and then, before the solder resist ink on the surface layer is cured, applying a dummy pressure to the solder resist ink layer using an ink leveling pressure head.

[0012] This solution also has the following effects:

[0013] After the circuit board is fabricated, a layer of solder resist ink is printed on its surface. Because the solder resist ink seeps into the traces and the density of the traces varies in different areas, the ink thickness can differ, resulting in an uneven surface. Before the solder resist ink cures, a pressure head is used to apply a dummy pressure (meaning low pressure is applied only to the ink layer) to the surface of the circuit board. After this dummy pressure, the thicker ink on the copper foil traces flows to the thinner areas, ensuring the ink thickness is the same regardless of the trace thickness, maintaining a thickness within 25+ / -10µm. This achieves a uniform surface smoothness on the PCB, improving its flatness. After the photosensitive chip is mounted on the PCB, this improves DA tilt (chip tilt), allowing light to pass perpendicularly through the lens and IR filter onto the photosensitive chip, thus enhancing the camera's resolution. Attached Figure Description

[0014] Figure 1This is a top view of the mobile phone camera PCB substrate with improved DA Tilt in an embodiment of this utility model.

[0015] Figure 2 This is a diagram showing the experimental results of the first group in the embodiments of this utility model.

[0016] Figure 3 This is a diagram showing the experimental results of the second group in the embodiments of this utility model. Detailed Implementation

[0017] The following detailed description illustrates the specific implementation method:

[0018] The markings in the accompanying drawings include: 1. Copper foil trace sparse area; 2. Copper foil trace dense area; 3. Copper foil line; 4. Cable tray.

[0019] The basic implementation examples are as follows: Figure 1 As shown: A mobile phone camera PCB substrate with improved DA (Dual Aspect Ratio) Tilt includes a substrate, the substrate including a surface layer and a solder resist layer disposed on the surface layer; the surface layer has a dense copper foil trace area 2 and a loose copper foil trace area 1; the solder resist layer has a uniform thickness in the dense copper foil trace area 2 and the loose copper foil trace area 1. The thickness of the solder resist layer is between 15µm and 35µm.

[0020] In the dense copper foil trace area 2, a wire groove 4 is provided between each copper foil trace, and a solder resist ink layer is also provided on the wire groove 4.

[0021] The solder resist ink layer is set by an ink leveling process, which involves printing the solder resist ink onto the surface layer to form a solder resist ink layer, and then, before the solder resist ink on the surface layer has cured, applying a false pressure to the solder resist ink layer using an ink leveling pressure head.

[0022] In the production process of mobile phone camera PCB substrates, after the circuit board is fabricated, a layer of solder resist ink is printed on its surface. However, due to the fluidity of the solder resist ink, it seeps into the grooves 4 between the copper foil lines 3 during printing. Furthermore, the density of lines varies in different areas of the circuit board, resulting in inconsistent thickness of the surface ink in different areas, thus causing unevenness in the circuit board.

[0023] To address this issue, a special ink leveling head is used to treat the ink on the circuit board surface before the solder resist ink has cured—a process known as "false pressing." False pressing involves applying relatively low pressure, applied only to the ink layer, to flatten it. After this process, the thicker ink on the copper foil traces 3 flows to the thinner areas, ultimately resulting in a more uniform ink thickness on the circuit board surface, regardless of whether the areas have traces or not. This allows for precise control of the ink thickness within a range of 25±10μm. This significantly improves the flatness of all areas on the PCB board surface.

[0024] When the image sensor is mounted on the treated PCB board, the previous DA Tilt (chip tilt) problem is effectively improved. At this time, light can pass smoothly through the lens and IR filter and shine perpendicularly onto the image sensor, greatly improving the camera's resolution and making the captured image clearer and more accurate.

[0025] To further verify the effectiveness of this embodiment, the inventors conducted the following experiment, which was divided into two groups. The first group used existing substrates that did not maintain uniform thickness of the solder resist ink layer on the dense copper foil trace area 2 and the sparse copper foil trace area 1. The second group used the substrate of the technical solution in this embodiment. Each group conducted several experiments, and each time four points were selected for thickness measurement. The maximum value was subtracted from the minimum value to obtain the corresponding flatness value.

[0026] The experimental results of the first group are as follows: Figure 2 As shown, the experimental results of the second group are as follows: Figure 3 As shown, based on the experimental results of the two sets of experiments above, it can be seen that the flatness of the existing substrates that do not maintain a uniform thickness of the solder resist ink layer on the dense copper foil trace area 2 and the sparse copper foil trace area 1 is at most within 30um, while the flatness of this embodiment can be controlled within 15um. Compared with the prior art, the flatness of the solution corresponding to this embodiment is better.

[0027] The above are merely embodiments of this utility model. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, based on the guidance provided in this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of this utility model. These should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A mobile phone camera PCB substrate to improve chip tilt, characterized by: The substrate includes a surface layer and a solder resist ink layer disposed on the surface layer; the surface layer has a dense copper foil trace area and a sparse copper foil trace area; the solder resist ink layer has a uniform thickness in the dense copper foil trace area and the sparse copper foil trace area.

2. The mobile phone camera PCB substrate for improving the chip tilt according to claim 1, wherein: The thickness of the solder resist ink layer is between 15µm and 35µm.

3. The mobile phone camera PCB substrate for improving the chip tilt according to claim 2, wherein: In the dense copper foil trace area, a groove is provided between each copper foil trace, and a solder resist ink layer is also provided on the groove.

4. The mobile phone camera PCB substrate for improving the chip tilt according to claim 3, wherein: The solder resist ink layer is set by an ink leveling process, which involves printing the solder resist ink onto the surface layer to form a solder resist ink layer, and then, before the solder resist ink on the surface layer has cured, applying a false pressure to the solder resist ink layer using an ink leveling pressure head.

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