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FPCB, PCB, Pcb Cleaning Solution, PCB Etching solution

Chemical processing equipment for Huawei Mate XT flexible PCB and foldable screen

Explore the full process and equipment used for manufacturing Huawei Mate XT’s foldable screen and flexible PCBs. Learn about chemical etching, LDI exposure, developers, strippers, and cleaning machines crucial for producing high-precision flexible circuits.

To analyze the chemical etching equipment used in manufacturing the Huawei Mate XT’s folding screen and folding PCB, you can break down the process into two parts: screen etching and PCB etching.

Huawei Mate XT

1. Folding Screen Etching

The flexible display for foldable devices like the Huawei Mate XT likely involves etching processes for organic and inorganic materials used in OLED (Organic Light-Emitting Diode) or AMOLED displays. Here’s how etching plays a role:

  • Materials Involved: The folding screen is typically made up of layers of organic compounds, thin metal films, and transparent conductive oxides (such as ITO – indium tin oxide).
  • Etching Method: Wet chemical etching or dry etching (plasma or ion-beam) may be used to pattern the electrodes and define the screen areas. This allows precise control over layer removal for pixel definition, transparent circuits, and metal traces.
  • Equipment:
    • Wet chemical etching machines: These machines handle materials like ITO, which need precise etching to form conductive pathways.
    • Dry etching equipment: For materials where plasma etching provides better control and sharper edges.

The etching must ensure uniformity and accuracy without damaging the flexible nature of the screen.

2. Folding PCB Etching

The folding PCBs (Flexible Printed Circuit Boards, FPCBs) in foldable devices involve chemical etching to create fine conductive traces on thin copper or other conductive materials. Here’s what’s involved:

  • Materials Involved: Flexible substrates such as polyimide (PI) or PET (polyethylene terephthalate), with copper or other metal layers used for the conductive pathways.
  • Etching Process: The primary method is chemical etching for subtractive manufacturing, where unwanted copper is removed to leave behind the desired circuit pattern. This is done using acidic solutions (like ferric chloride or cupric chloride).
  • Equipment:
    • Roll-to-roll etching machines: These are commonly used in high-volume production for flexible circuits. They are designed to handle continuous sheets of substrate material, enabling efficient large-scale production.
    • Precision etching machines: These machines are capable of producing fine lines and intricate patterns required for folding PCBs, ensuring flexibility and durability without compromising electrical performance.

Additional Considerations

  • Masking Process: Both the screen and PCB require photoresist application and development to mask areas that should not be etched. This is commonly done with photoresist coating machines and UV exposure systems.
  • Cleanroom Environment: Due to the precision required, these processes take place in a cleanroom environment to avoid contamination, especially for display components.
  • Etching Control: Real-time monitoring and control systems are critical to ensure etch depth uniformity, particularly for thin and flexible materials.

By using a combination of chemical etching and advanced processing equipment, manufacturers can create the fine, flexible structures required for both the screen and folding PCBs in devices like the Huawei Mate XT.

HUAWEI Mate XT Hands-on & Quick Review: Huawei leads the foldable phone trend again
HUAWEI Mate XT Hands-on & Quick Review

Here’s a comprehensive list of the chemical processing equipment typically involved in the production of flexible PCBs (FPCBs), along with the corresponding steps:

1. Material Preparation

  • Laminators: Used to apply the copper-clad film onto the flexible substrate (e.g., polyimide or PET).

2. Photoresist Application

  • Coaters: Machines for applying a layer of photoresist (dry film or liquid photoresist) on the copper surface. This is critical for defining the circuit pattern during the etching process.

3. Laser Direct Imaging (LDI) Exposure

  • LDI Exposure Machines: These systems expose the photoresist layer to UV light in the exact circuit pattern based on CAD files. LDI ensures high precision, especially for the fine lines needed in flexible PCBs.

4. Development Process

  • Developers: Once the photoresist is exposed, developers are used to wash away the unexposed areas of the photoresist, leaving only the areas that will protect the copper during etching. Alkaline solutions are commonly used for this process.

5. Etching Process

  • Chemical Etching Machines: These remove the unmasked copper to form the circuit traces. Ferric chloride or cupric chloride is used for copper etching. For flexible PCBs, this equipment is often in a roll-to-roll configuration to handle continuous substrates efficiently.

6. Stripping Process

  • Strippers: After etching, the remaining photoresist (which protected the copper traces) needs to be removed. Strippers use chemical solutions like alkaline-based chemicals to strip the photoresist.

7. Cleaning and Drying

  • Cleaning Machines: The FPCB needs thorough cleaning to remove residues from the etching and stripping processes. Cleaning machines use deionized water or other specialized cleaning agents.
  • Dryers: High-precision drying equipment is used to completely dry the flexible PCBs to avoid defects caused by residual moisture.

8. Solder Mask Application (Optional)

  • Coaters: A solder mask can be applied to protect the copper traces except for areas where components will be soldered. This is done using spray coating or screen printing.
  • LDI Machines: Similar to earlier, LDI exposure machines may be used to precisely define the areas where the solder mask should be removed.

9. Post-Processing

  • Surface Treatment: Flexible PCBs often undergo surface treatments like electroless nickel immersion gold (ENIG) or OSP (organic solderability preservative) to enhance solderability and prevent oxidation.
  • Cutting/Profiling: Finally, the flexible PCBs may need to be cut into specific shapes using laser cutters or CNC routers.

10. Testing

  • Automated Optical Inspection (AOI): This machine scans the finished flexible PCB to check for defects like open circuits or short circuits.
  • Electrical Testing Equipment: To verify the electrical properties of the circuits, ensuring functionality.

Summary of Equipment:

  1. Laminators (for applying copper-clad film)
  2. Photoresist Coaters (dry film or liquid)
  3. LDI Exposure Machines (for circuit pattern imaging)
  4. Chemical developing machine (to remove unexposed photoresist)
  5. Chemical Etching Machines (ferric or cupric chloride)
  6. Chemical Stripper Machine (for removing remaining photoresist)
  7. Chemical Cleaning Machines (for post-etching and stripping)
  8. Dryers (to eliminate moisture)
  9. Coaters and LDI for Solder Mask (optional)
  10. Surface Treatment Equipment (for solderability)
  11. Cutting Machines (laser or CNC for profiling)
  12. AOI and Electrical Testing Machines (for inspection)

These steps ensure that the flexible PCB is precisely etched, cleaned, and ready for further assembly into complex devices like Huawei’s foldable Mate XT.

PCB

The Advantages of Rigid Flex PCB – Production Process, Uses, and Top Manufacturers

rigid flex pcb

Learn about the benefits of using rigid flex PCBs, including their production process and use cases such as fingerprint technology. Discover top manufacturers and the equipment required for production.

igid-flex PCBs, also known as hybrid PCBs, are a combination of rigid and flexible circuit boards that are interconnected by plated through-holes. These circuit boards offer a variety of advantages over traditional PCBs, including increased reliability, reduced weight and space requirements, and enhanced design flexibility. In this article, we’ll explore the advantages of rigid-flex PCBs, their production process, and some of their common applications.

What is Rigid Flex PCB?

Rigid-flex PCBs are a type of printed circuit board that combines the characteristics of rigid and flexible circuits into a single design. These boards consist of multiple layers of flexible circuitry, which are laminated together with layers of rigid circuitry. The flexible sections of the board are typically used to connect components, while the rigid sections are used to mount components and provide mechanical stability.

Advantages of Rigid-Flex PCBs:

  1. Increased Reliability: The flexibility of these circuit boards makes them less susceptible to damage from mechanical stresses, vibration, and thermal expansion, which can improve their reliability.
  2. Reduced Weight and Space Requirements: The use of flexible circuitry can reduce the overall weight and size of the board, making them ideal for use in portable devices and other applications where space is limited.
  3. Enhanced Design Flexibility: The use of flexible circuitry also allows for more complex and intricate designs, which can improve performance and reduce manufacturing costs.
  4. Improved Signal Integrity: The use of flexible circuitry can reduce the number of interconnects required, which can improve signal integrity and reduce the potential for interference.
  5. Cost-Effective: Despite their many advantages, rigid-flex PCBs can be produced at a cost that is comparable to traditional PCBs, making them an attractive option for a wide range of applications.

Production Process of Rigid-Flex and Flexible PCBs:

The production process of rigid-flex PCBs involves several steps, including design, fabrication, and assembly. The design process typically involves the use of computer-aided design (CAD) software to create a 3D model of the board. This model is then used to generate the necessary manufacturing files, which are used to produce the board.

The fabrication process for rigid-flex PCBs involves a combination of flexible and rigid circuit board manufacturing techniques. The flexible circuitry is typically produced using a photo-etching process, while the rigid circuitry is produced using a subtractive or additive process.

Once the circuit boards have been produced, they are assembled together using plated through-holes, which are used to create electrical connections between the different layers of the board. The assembly process also involves the placement of components, which are then soldered onto the board.

Use of Fingerprint Rigid-Flex PCB:

One of the most common applications of rigid-flex PCBs is in fingerprint sensors. These sensors require a high degree of flexibility, which can be achieved using flexible circuitry. The rigid sections of the board are used to mount the sensor components and provide mechanical stability.

Cost:

The cost of producing rigid-flex PCBs can vary depending on the complexity of the design, the number of layers, and the volume of the order. However, rigid-flex PCBs are typically more expensive than traditional PCBs due to the additional manufacturing steps and materials required.

Famous Manufacturers:

Some of the well-known manufacturers of rigid-flex PCBs include:

  1. Flex PCB Inc.
  2. San Francisco Circuits
  3. Sierra Circuits
  4. Advanced Circuits
  5. Epec Engineered Technologies

Equipment Required for Production:

The production of rigid-flex PCBs requires several specialized pieces of equipment, including:

  1. Etching machine: This machine is used to remove unwanted copper from the surface of the PCB using a chemical solution. It typically consists of a tank filled with the etchant solution, and a mechanism for moving the PCB through the solution.
  2. Plating machine: This machine is used to add a layer of metal to the surface of the PCB in order to enhance its electrical conductivity and protect it from corrosion. It typically consists of an electroplating bath containing a solution of metal ions, and a mechanism for applying an electric current to the PCB.
  3. Photoresist equipment: This equipment is used to apply the photoresist material to the surface of the PCB, and to expose it to UV light in order to selectively harden the photoresist in the areas where the copper is to be retained.
  4. Clean room facilities: Clean rooms are used to prevent contamination of the PCB during production, and to ensure that the final product meets the required quality standards. Clean rooms typically have controlled air flow, humidity, and temperature, and are equipped with specialized equipment for handling and assembling PCBs.
  5. Testing and inspection equipment: Once the PCB has been produced, it must be tested and inspected to ensure that it meets the required quality standards. This typically involves using specialized equipment to test the electrical conductivity and other properties of the PCB, and to inspect it for defects and other issues.