Guide to Enhanced Heat Dissipation Printed Circuit Boards

The structure, manufacturing methods, and applications of printed circuit boards (PCBs) with electronic components. The core of this patent lies in improving heat dissipation efficiency by directly connecting heat dissipation elements to the wiring layer of the PCB, allowing for embedding in high-heat components such as power amplifiers.

Key Concepts and Components

1. Printed Circuit Board (PCB) 100:

• Board Part 40: A multilayer structure that includes insulation layers and wiring layers.
• First Substrate 10: The central part of the PCB, typically composed of multiple insulation layers (L1-L4) and wiring layers (42-46), containing a component accommodating part 49.
• Component Accommodating Part 49: A cavity in the first substrate 10 for housing electronic components 1.
• Insulating Member 49a: An insulating material that fills the space around electronic component 1 in the component accommodating part 49.
• Upper Second Substrate 20a and Lower Second Substrate 20b: Additional layers stacked on the top and bottom surfaces of the first substrate 10, containing insulation layers (L5, L6) and wiring layers (41, 47).
• Insulating Protection Layer 30: The outermost solder mask layer of the board part, with openings exposing connection pads and heat dissipation pads.
• Wiring Layers (41-47): Formed by patterned metal layers (such as copper foil) for electrical connections.
• Connection Pads (41a, 47a): Surface features for mounting electronic components or connecting external terminals.
• Interlayer Connection Conductor 48: Conductors that connect different wiring layers or connection pads (e.g., vias).

1. Electronic Component 1:

• Heat Generating Component 2: A component that generates a large amount of heat during operation (e.g., power amplifier).
• Heat Dissipation Member 3: A component attached to the heat generating component 2 for dissipating heat to the outside (e.g., a heat sink made of copper material).
• Bonding Part 4: The material that connects the heat dissipation member 3 to the heat generating component 2 (e.g., solder paste or thermal tape).

1. Heat Dissipation Mechanism:

• Heat Dissipation Pad 47b: A part of the lower second substrate 20b’s bottom wiring layer 47, directly connected to the heat dissipation member 3. One surface contacts the heat dissipation member 3, while the other surface is exposed to the outside.
• Heat Dissipation Terminal 51 (in the electronic component module): Connects the heat dissipation pad 47b to the main board 90, further enhancing heat dissipation.

1. Key Points of the Manufacturing Method:

• Construct the first substrate by stacking insulation layers and forming wiring layers.
• Form the component accommodating part in the first substrate.
• Place pre-assembled heat generating components and heat dissipation members in the component accommodating part.
• Expose the heat dissipation member by removing (e.g., grinding) or forming vias in the insulation layer.
• Form upper and lower second substrates on the outer surface of the first substrate, ensuring the heat dissipation member is directly connected to the heat dissipation pad on the lower second substrate.

Learning Objectives

Upon completing this learning guide, you should be able to:

• Identify and describe the structure of the printed circuit board and its components as outlined in the patent.
• Explain the functions and compositions of electronic components and their heat dissipation members.
• Understand the key innovations that improve heat dissipation efficiency in this PCB design.
• Outline the main steps in manufacturing such PCBs.
• Explain the heat dissipation path in electronic component modules.
• Compare two different methods of exposing heat dissipation members.

Quiz: Short Answer Questions

Please answer the following questions in 2-3 sentences:

1. What are the core layers that make up the “board part” of a printed circuit board (PCB)? What role do they play in the overall structure of the board?
2. What are the main components of electronic component 1? What are their primary functions?
3. What is the role of the component accommodating part 49? Why is the insulating member 49a set within it?
4. How is the heat dissipation member 3 connected to the heat generating component 2? What impact does this connection have on heat dissipation?
5. In the patent, how is the position and function of the heat dissipation pad 47b described in the heat dissipation path?
6. What are the main advantages of the heat dissipation structure described in the patent compared to traditional heat dissipation methods?
7. What is the thickness relationship between the first substrate 10 and electronic component 1 during the manufacturing of this PCB? What significance does this have in design?
8. What are the two main methods to expose the heat dissipation member 3 during the manufacturing process?
9. What other key parts are included in the electronic component module besides the PCB and electronic components? What are their functions?
10. If the heat generating component 2 is a power amplifier, what material is the heat dissipation member 3 typically made of?

Quiz Answers

1. The “board part” of the printed circuit board is primarily composed of multiple alternating stacked insulation layers and wiring layers. Together, they form the electrical interconnection and mechanical support framework of the PCB, providing structure and functional environment for embedded components.
2. Electronic component 1 includes heat generating component 2 and heat dissipation member 3. Heat generating component 2 is a component that generates a large amount of heat during operation (such as a power amplifier), while heat dissipation member 3 is responsible for effectively dissipating this heat to the outside, preventing overheating of the component.
3. The component accommodating part 49 is a cavity in the first substrate 10 for housing electronic component 1. The insulating member 49a is set within it to fill the space between the electronic component and the substrate, thereby securing the electronic component and providing electrical insulation.
4. The heat dissipation member 3 is connected to the heat generating component 2’s invalid surface through the bonding part 4 (e.g., solder paste or thermal tape). This direct connection effectively transfers the heat generated by the heat generating component to the heat dissipation member, which is key to improving heat dissipation efficiency.
5. The heat dissipation pad 47b is located on the bottom wiring layer 47 of the board part, directly bonded to the surface of the heat dissipation member 3. Its function is to conduct the heat from the heat dissipation member directly to the outside or further conduct it to the main board through connection terminals, achieving efficient heat dissipation.
6. Compared to traditional methods of heat dissipation through vias or narrow wiring patterns, the heat dissipation structure described in this patent combines the heat dissipation member directly with the invalid surface of the heat generating component and connects it directly to the external heat dissipation pad. This significantly increases the heat dissipation area and path, thereby improving heat dissipation efficiency.
7. In the patent, the total thickness of electronic component 1 (including heat dissipation member 3 and heat generating component 2) is typically thicker than the thickness of the first substrate 10. This means that part of the heat dissipation member protrudes from the first substrate and is embedded in the lower second substrate for subsequent exposure and connection to the heat dissipation pad.
8. During the manufacturing process, there are two main methods to expose the heat dissipation member 3. The first is to grind the insulation layer L6 stacked on the heat dissipation member until it is exposed; the second is to form a via H in the insulation layer L6, then fill the via with heat dissipation pad 47b and connect it to the heat dissipation member.
9. The electronic component module includes not only PCB 100 and electronic component 5 but also sealing part 60 and connection terminal 50. The sealing part 60 seals and protects the electronic components from short circuits and external impacts; the connection terminal 50 is used to electrically and physically connect the electronic component module to the main board 90.
10. If the heat generating component 2 is a power amplifier, the heat dissipation member 3 is typically made of a metal material with high thermal conductivity, such as a heat sink made of copper. Copper is commonly used for its excellent thermal conductivity.

Suggested Paper Questions

1. Explain in detail how the printed circuit board design described in patent CN107787112B significantly improves thermal management efficiency by integrating heat generating components and heat dissipation members. In your answer, compare this method with the thermal challenges of existing technologies.
2. Analyze the method proposed in the patent for manufacturing printed circuit boards with electronic components. Focus on the main steps from the formation of the first substrate to the exposure of the heat dissipation member, and discuss the impact of each step on the performance of the final product.
3. Discuss the key roles of the heat dissipation pad 47b and heat dissipation terminal 51 in the heat dissipation path and efficiency enhancement of the entire electronic component module in this printed circuit board design.
4. Compare the two different methods of exposing and connecting heat dissipation members shown in Figures 1 and 8 (grinding vs. via), analyzing their respective advantages and disadvantages, and which method might be prioritized in specific application scenarios.
5. Based on the technology described in the patent, explore how this integrated design of electronic components and optimized heat dissipation contributes to the miniaturization and lightweighting of modern electronic devices. What further developments or applications do you foresee for this technology in the future?

Glossary of Terms

• Printed Circuit Board (PCB): A board that connects electronic components through conductive paths (wiring layers).
• Board Part: The part that constitutes the main structure of the printed circuit board, including multiple layers of insulation and wiring.
• First Substrate: The central core layer of the printed circuit board, typically containing the component accommodating part.
• Component Accommodating Part: A cavity formed in the substrate for housing electronic components.
• Second Substrate: Additional layers stacked on the outer surface of the first substrate, divided into upper and lower parts.
• Electronic Component<: Integrated circuits or other electronic devices embedded in the PCB.
• Heat Generating Component: An electronic component that generates a large amount of heat during operation, such as a power amplifier.
• Heat Dissipation Member: A part attached to the heat generating component for dissipating heat, such as a heat sink.
• Invalid Surface: The surface of the heat generating component that bonds with the heat dissipation member, typically the back side opposite the effective surface (where terminals are located).
• Wiring Layer: A layer made of conductive material (such as copper) in the PCB for forming electrical connections.
• Connection Pad: Surface areas on the wiring layer for soldering or connecting other electronic components.
• Heat Dissipation Pad: Specific areas on the wiring layer that directly contact the heat dissipation member for thermal conduction.
• Interlayer Connection Conductor: Conductive structures that connect different wiring layers or surface connection points, such as vias.
• Insulating Protection Layer: Typically made of solder mask, covering the PCB surface, providing protection and defining exposed pad areas.
• Bonding Part: The material that connects the heat generating component and heat dissipation member, such as solder paste or thermal tape.
• Insulating Member: Insulating material that fills the space around electronic components in the component accommodating part.
• Electronic Component Module: An integrated unit that includes the printed circuit board, electronic components mounted on it, and sealing parts.
• Sealing Part: The material that encapsulates electronic components, providing protection and insulation.
• Connection Terminal: External connection points for connecting the electronic component module to the main board, such as solder balls.
• Heat Dissipation Terminal: Special connection terminals for transferring heat from the heat dissipation pad to the outside (e.g., main board).
• Power Amplifier: A high-heat electronic component whose heat dissipation needs drive the design of this patent.
• Through Hole: Holes formed in the substrate that can be used to connect different layers or expose heat dissipation members.
• Grinding: The process of removing material from a surface through friction, which can be used to expose heat dissipation members.
• Wafer: Thin slices used to manufacture multiple semiconductor devices.
• Copper Clad Laminate (CCL): A substrate material with a surface covered with copper foil, used in PCB manufacturing.