Article

RSS

This article will examine some of the different material options that are available to bond other dielectrics together to make a multilayer board and discuss the characteristics that are important to consider when making the material selection for the board.

Mixing different materials in the same board allows multilayers to be constructed in many different ways that may either improve performance or reduce costs, and often achieve both. Some new methods and materials can also facilitate sequential lamination that allows further use of blind and buried vias and can incorporate microwave and digital functions in the same board. Some of the combinations can be fabricated using conventional PWB processes while others require a careful selection of materials and an understanding of the order in which they must be put together in order to avoid manufacturability problems.

Bonding Material Choices

• PTFE Fusion
• FEP
• CuClad 6700
• CuClad 6250
• CLTE-P
• CLTE-PC
• 25N
• Polyimide
• Epoxy

Above is a listing of common materials that are used to bond laminates together to either form stripline circuits or more complex multilayer boards. Polytetrafluoroethelene fusion has been used for many years and is a process by which you exceed the melting point of the thermoplastic polymer of the laminate and fuse different layers together.

The next five items are thermoplastic fluoropolymers with lower melting points than PTFE, allowing bonding of PTFE based laminates without melting the layers. 25N is a low loss thermoset that can be used in a wide variety of applications. The last 2 are conventional thermoset products that can also be used in certain locations of microwave boards where the loss is not critical such as between planes, or as the portion of the board that handles lower frequency digital functions.

© Arlon Materials For Electronics

Click Here To Download:
•Featured Article: Combining Dielectrics In Multilayer Microwave Boards