Tom
10-07-2002, 08:42 PM
IPC Advanced Study Guide Page Reference: Page 4, Section 1.1
There are many different material properties that can be measured in a laminate. Some of the different materials and properties are:
Resin Systems - serve as the binder materials that bond reinforcements and metal foils
Epoxies - It's among the most commonly used resin systems for PCBs, including standard, multifunctional and high temperature resins
Polyimide - Offers the highest operating temperature among resin systems in use today and a favorite for military applications
Cyanate Ester - Offers a range of attractive properties both electrical and physical is second only to polyimide in thermal performance
Bismaleimide Triazine - Is the most popular choice for the construction of BGA packages
Reinforcements - Provides the dimensional stability and mechanical properties of the organic substrate laminate
Glass Cloth - Most commonly used reinforcement for PCB substrates and available in a number of different thicknesses and chemical make-ups
Glass Felt - Nonwoven glass mat is most commonly used in combination with fluoroplastic resins
Aramid - Aramid cloth has been used to reinforce certain laminates. It has a negative CTE in the X and Y direction, which helps to offset the in-plane CTE of the resin. A drawback of the material is a high Z-axis CTE.
Aramid Paper - Is being effectively used in a number of multilayer applications. They have most of the benefits of the aramid cloth with more process latitude. Because the material is organic, it has the added advantage of being easily processed by either laser or plasma for making holes.
Metal Foils - Commonly used to provide the raw material for the creation of circuit conductors. Copper is the most commonly used metal foil. Common thickness are 17um (half ounce), 35um (one ounce), 70um (two ounce).
Flexible laminates - Serves those applications where an assembled circuit is to be bent, folded or flexed during use if required for the application
Polyimide films - Same general chemical makeup as rigid polyimides, these materials have excellent thermal properties. Has relatively low dielectric constants making them attractive for higher speed design and cabling applications.
Polyester films - Used for many low-end applications where high temperatures will not be experienced. Soldering parts to flexible circuits needs to be accomplished with great care.
Key Environmental Material Properties
While there are many different material properties that can be measured in a laminate, only a few have of overriding importance in circuit design. These properties are:
Thermal expansion (CTE) Measured in parts per million in change of temperature
Glass transition temperature (Tg) Related to the expansion in the Z axis where bonded material delaminates at a high temperature
Moisture absorption
There are many different material properties that can be measured in a laminate. Some of the different materials and properties are:
Resin Systems - serve as the binder materials that bond reinforcements and metal foils
Epoxies - It's among the most commonly used resin systems for PCBs, including standard, multifunctional and high temperature resins
Polyimide - Offers the highest operating temperature among resin systems in use today and a favorite for military applications
Cyanate Ester - Offers a range of attractive properties both electrical and physical is second only to polyimide in thermal performance
Bismaleimide Triazine - Is the most popular choice for the construction of BGA packages
Reinforcements - Provides the dimensional stability and mechanical properties of the organic substrate laminate
Glass Cloth - Most commonly used reinforcement for PCB substrates and available in a number of different thicknesses and chemical make-ups
Glass Felt - Nonwoven glass mat is most commonly used in combination with fluoroplastic resins
Aramid - Aramid cloth has been used to reinforce certain laminates. It has a negative CTE in the X and Y direction, which helps to offset the in-plane CTE of the resin. A drawback of the material is a high Z-axis CTE.
Aramid Paper - Is being effectively used in a number of multilayer applications. They have most of the benefits of the aramid cloth with more process latitude. Because the material is organic, it has the added advantage of being easily processed by either laser or plasma for making holes.
Metal Foils - Commonly used to provide the raw material for the creation of circuit conductors. Copper is the most commonly used metal foil. Common thickness are 17um (half ounce), 35um (one ounce), 70um (two ounce).
Flexible laminates - Serves those applications where an assembled circuit is to be bent, folded or flexed during use if required for the application
Polyimide films - Same general chemical makeup as rigid polyimides, these materials have excellent thermal properties. Has relatively low dielectric constants making them attractive for higher speed design and cabling applications.
Polyester films - Used for many low-end applications where high temperatures will not be experienced. Soldering parts to flexible circuits needs to be accomplished with great care.
Key Environmental Material Properties
While there are many different material properties that can be measured in a laminate, only a few have of overriding importance in circuit design. These properties are:
Thermal expansion (CTE) Measured in parts per million in change of temperature
Glass transition temperature (Tg) Related to the expansion in the Z axis where bonded material delaminates at a high temperature
Moisture absorption