Views:67 Author:Site Editor Publish Time: 2019-07-04 Origin:Site
The demand for multi-layer Printed Circuits boards is growing rapidly, that suitable for the demand of the smaller, lighter boards and used in electrical devices, such as military equipment, smart home health care equipment.
The multi-layer Printed Circuits boards Could perfectly use on the smartphones and computers as the multi-layer Printed Circuits boards advantage.
From a technical standpoint, there are numerous advantages to the use of multi-layer designs, over and above saving space and weight:
1. By incorporating multiple layers in a single PCB, boards can increase functionality.
2. Manufacturing processes for multi-layer boards result in high-quality, reliable end products.
3. Multi-layer boards by their innate electrical properties provide high capacity and high speed in a smaller footprint.
4. Higher density of assembly.
5. Connectors required for multiple separate PCB are reduced or eliminated, simplifying construction and further reducing weight.
6. Multi-layer Printed Circuits boards can be manufactured in both rigid and flexible construction. Be advised though, that the more layers incorporated in a flex PCB, the less flexible it becomes.
Multi-layer PCB - Technical specification
|Number of layers||4 – 22 layers standard, 28 layers prototype.|
|Technology highlights||Multiple layers of epoxy glass fiber bonded together with multiple layers of copper of varying thicknesses.|
|Materials||Standard, High performance FR-4, Halogen-free FR-4, Low loss and High frequency materials, PTFE|
|Copper weights (finished)||18um – 420um|
|Minimum track and gap||0.075 mm / 0.075 mm|
|PCB thickness||0.35 mm – 10.0 mm|
|Maximum dimensions||580 mm x 800 mm, advanced 610 mm x 1000 mm|
|Surface finishes available||HASL (SnPb), LF HASL, OSP, ENIG, ENEPIG, Immersion Tin, Immersion Silver, Electroplate gold, Gold fingers|
|Minimum mechanical drill||0.15 mm|
Processes for Manufacturing multi-layer Printed Circuits boards
Due to the sheer demand for multi-layer Printed Circuits boards for use in technology devices, healthcare equipment, military use, and even such consumer products as smart televisions and home monitoring equipment, most competitive manufacturers have positioned themselves to respond to the need for these boards. There remains a mix of capabilities among fabricators related to volume production capabilities, and the numbest of PCB layers that can be produced.
Manufacturing of multi-layer Printed Circuits boards involves a process of combining alternating layers of pre preg and core materials into a unit, utilizing heat and high pressure to ensure uniform encapsulation of conductors, elimination of air between layers, and proper curing of adhesives that bind the layers together.
Due to the multiple layers of material, execution of drill holes among layers must be carefully observed and registered. It’s important for successful manufacturing of multi-layer Printed Circuits boards that engineers incorporate symmetrical layout across layers, to help avoid twisting or bow in the materials when heat and pressure are applied.
When sourcing a fabricator for multi-layer Printed Circuits boards, it is critically important to acquire the manufacture’s capabilities and standard tolerances for these complex boards, and utilize design for manufacturing (DFM) techniques to accommodate those standards. This goes a long way toward building confidence that the result will meet all functional, reliability, and performance expectations.
Every technology has pros and cons, and multi-layer Printed Circuits boards are not immune from negative attributes:
1. Cost–one of the primary negatives in designing and implementing multi-layer Printed Circuits boards is the cost. As specialized processes are involved in the manufacturing of these boards, there is a considerable investment required for fabricators to offer these services. This makes the cost of multi-layer boards higher than a traditional single or double-sided board.
2. Service availability-not all PCB manufacturers have made the commitment to manufacturing these complex boards, limiting the resource options available to PCB designers.
3. Compactness of multi-layer boards generates design concerns for such issues as cross talk and impedance problems.
4. With increased functionality comes the need for more extensive testing of a single PCB. Manufacturing cycles may also be longer, due to the very complexity of the manufacturing process.
5. Repairing a multi-layer Printed Circuits boards can be extremely difficult, and may even be unfeasible or impossible. This makes failure of a multi-layer board costly, since it may need to be totally replaced.
6. Interconnection between layers is critical for board function, making design and fabrication of microbial and overall density critical.