Circuit Board Cavity Structure to Prevent Insulating Layer Sagging
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Solution Overview
Problem
Conventional methods for forming cavities in multi-layer circuit boards result in thickness differences between insulating layers due to sagging of upper layers, leading to issues with cavity collapse and difficulty in connecting semiconductor chips, which affects yield and increases material costs.
Innovation Solution
A circuit board design with overlapping through-holes in perpendicular insulating layers, where the inner walls of the second through-hole overlap the first through-hole, minimizing thickness differences and preventing sagging, allowing for flip-bonding of semiconductor chips without the need for additional etching resist layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to form cavities in multi-layer circuit boards, then the cavity structure can be formed, but thickness differences occur between insulating layers due to sagging of upper layers
Solution Approach 1:
The patent applies preliminary anti-action by forming a support structure within the cavity before the upper insulating layer is applied. This support structure prevents the upper layer from sagging into the cavity during subsequent processing steps, thereby maintaining thickness uniformity and preventing the thickness difference problem before it occurs.
Solution Approach 2:
The patent segments the cavity formation process into multiple steps: first forming the cavity in the lower insulating layer, then adding a support structure, and finally forming the upper insulating layer. This segmentation allows each step to be optimized independently, ensuring both cavity integrity and layer thickness uniformity.
2Adaptability or versatility
If the cavity structure is formed with thickness differences, then the cavity can accommodate electronic components, but cavity collapse occurs and connection of semiconductor chips becomes difficult
Solution Approach 1:
The patent implements beforehand cushioning by introducing a support structure into the cavity before placing electronic components. This support structure acts as a cushion that prevents cavity collapse under the weight of components and maintains the cavity's structural integrity throughout the assembly process.
Solution Approach 2:
The support structure serves as an intermediary element between the cavity walls and the electronic components. It mediates the mechanical stresses and forces, preventing direct contact that could cause cavity collapse while still allowing proper placement and connection of semiconductor chips.
3Ease of manufacture
If conventional cavity formation methods are used, then the basic cavity structure is achieved, but additional etching resist layers and subsidiary materials are required
Solution Approach 1:
The patent merges the support structure function with the cavity formation process itself. By integrating the support structure into the cavity wall formation steps, the patent eliminates the need for separate etching resist layers and subsidiary materials, simplifying the overall manufacturing process while maintaining cavity integrity.
Solution Approach 2:
The cavity structure is designed to be self-supporting through the integrated support structure, eliminating the need for external subsidiary materials like etching resist layers. The structure serves its own support function, reducing device complexity and material requirements.
Data Source
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AI summary
The present embodiment relates to a circuit board and a semiconductor package. A circuit board according to one aspect comprises a first insulating layer; a second insulating layer disposed on the first insulating layer and including a first through-hole; and a third insulating layer disposed on the second insulating layer and including a second through-hole overlapped in a direction perpendicular to the first through-hole, wherein the second insulating layer is disposed on the first insulating layer and includes a third through-hole overlapped in a direction perpendicular to the second through-hole, and the inner wall of the second through-hole overlaps at least a portion of the inner wall of the first through-hole in a vertical direction.