Exam 3

• Mulit core build-up

  • Easy to manufacture

  • Mechanical drills

  • Blind vias

  • Cost effective

  • Low material stress

  • Most often produced

• Sequential build-up

  • Know as HDI (high density interconnect)

  • More drill configurations

  • Higher cost

  • More material stress

• Flexible PCBs

  • Flexible and rigid part

  • Often used to decouple vibrations

  • Flex part can act as cable

• Bus systems

• Power supplies

• Analog signals

• Critical signals

Electrons passing through vias can create friction on the metal inner layer of the platting -> this could lead to holes and in the worst case causes a connection lost inside the via

• Copper Migration: The unwanted movement of copper ions through the PCB material, often due to electrochemical reactions.

  • Effects: Can lead to short circuits, increased resistance, and overall degradation of the PCB's performance.

• micro cracks in vias: Because of termal stress cracks can develop within vias.

  • Solution: filled vias

    • Problem: Partial Filling: Vias not completely filled, leading to reliability issues.

• Thermal Resistance: A measure of a material's ability to resist the flow of heat

• Importance: It determines the efficiency of heat dissipation from electronic components, crucial for preventing overheating and ensuring reliable operation.

• Heat Spreader: A component used to distribute heat away from hotspots to larger areas, improving thermal management.

• Role: Helps to maintain lower temperatures across the PCB, enhancing component reliability and performance

• Yes, thermal resistance can be simulated using software tools such as Ansys, COMSOL, or dedicated thermal simulation software to model heat flow and predict temperature distributions.

• Multiple Thermal Resistances: A typical circuit contains multiple thermal resistances in series and parallel, representing various paths for heat dissipation through different materials and interfaces.

• Embedded Components: Passive and active components integrated within the PCB substrate, rather than mounted on the surface.

• Usage:

  • Space Saving: Reduces the overall size of the PCB.

  • Performance: Enhances electrical performance by reducing parasitic inductance and resistance.

  • Thermal Management: Improves heat dissipation by distributing heat within the PCB layers.

• CCE Process (Chip-on-Chip Embedding): A method of integrating multiple ICs or components within a single package, stacked on top of each other and embedded within the PCB.

• Advantages:

  • Miniaturization: Reduces the overall footprint of the electronic assembly.

  • Performance: Enhances electrical performance by shortening interconnect lengths.

  • Integration: Enables high-density integration of components, beneficial for advanced applications like smartphones and high-performance computing.