Electronic Component Built-in Substrate Insulating Layer Flatness
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Solution Overview
Problem
The manufacturing of electronic component built-in substrates faces challenges in forming fine wiring layers due to poor flatness of the resin layer, especially when the electronic component thickness is thinner than the core substrate, leading to depressed resin layers and difficulties in achieving good yield during the formation of fine wiring layers.
Innovation Solution
The solution involves forming a first inner insulating layer to seal the electronic component and a second outer insulating layer on the substrate, which are then used to create a flat surface by hot pressing resin films, ensuring the same heat history for both layers to facilitate the formation of roughened surfaces for anchoring wiring layers, thereby improving adhesion and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin film is hot pressed to bury resin into the gap around the electronic component, then the electronic component is sealed and insulated, but the resin layer becomes depressed at the opening portion when the component thickness is less than substrate thickness, resulting in poor flatness
Solution Approach 1:
The insulating layer is divided into two separate layers: a first insulating layer formed directly on the substrate to fill the opening portion and seal the electronic component, and a second insulating layer formed on the first insulating layer to provide a flat surface. This segmentation allows each layer to fulfill its specific function without compromising the other.
Solution Approach 2:
The solution adds a vertical dimension by introducing a second insulating layer above the first insulating layer. This additional layer compensates for the depression in the first layer, restoring the required flatness at the surface level without affecting the sealing function of the first layer.
2Volume of stationary object
If the resin layer is depressed at the opening portion, then the volume of burying space is large, but it becomes difficult to form fine wiring layers with good yield
Solution Approach 1:
The insulating structure is segmented into two functional layers: the first insulating layer maintains the volume needed for burying and sealing, while the second insulating layer provides the flat surface required for precise wiring formation. This segmentation decouples the conflicting requirements of volume and flatness.
Solution Approach 2:
By adding the second insulating layer in the vertical dimension, the solution preserves the large volume of the first insulating layer for burying purposes while simultaneously creating a flat upper surface for fine wiring layer formation, thus resolving the contradiction between volume and manufacturing precision.
3Device complexity
If a single insulating layer is formed to seal the electronic component, then the structure is simple, but the surface flatness is poor and adhesion for wiring layers is insufficient
Solution Approach 1:
The single insulating layer is segmented into two distinct layers with different functions: the first insulating layer for sealing and filling, and the second insulating layer for providing a flat bonding surface. This segmentation increases structural complexity but resolves the surface flatness issue.
Solution Approach 2:
Each insulating layer is given different local qualities: the first insulating layer has high filling capability and sealing properties, while the second insulating layer has smooth surface characteristics suitable for adhesion. This local differentiation allows each layer to optimize its specific function.
4Reliability
If the same heat history is applied to both insulating layers during hot pressing, then adhesion and surface roughness for anchoring wiring layers is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The formation of both insulating layers and the application of heat treatment are merged into a single integrated process step. Both layers are formed and subjected to the same heat history simultaneously, which simplifies the overall manufacturing process while ensuring consistent adhesion properties.
Solution Approach 2:
The first insulating layer is formed in advance to seal the electronic component before the second insulating layer is added. This preliminary action ensures that the sealing function is established before the flat surface layer is introduced, allowing subsequent processing to focus on surface quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the successful formation of fine wiring layers with improved adhesion and surface roughness, addressing the issue of depressed resin layers and enhancing the overall manufacturing process efficiency.
Implementation Method 1
there is a step of hot pressing a resin film to bury the resin into a gap around the electronic component arranged in the opening portion of the core substrate
Data Source
AI summary
An electronic component built-in substrate, includes, a substrate having an opening portion, a first wiring layer formed in the substrate, an electronic component arranged in the opening portion, a first insulating layer formed on one face of the substrate and sealing the electronic component, a second insulating layer formed on other face of the substrate, a second wiring layer formed on the first insulating layer, and a third wiring layer formed on the second insulating layer. The first insulating layer is formed of an inner insulating layer covering the one face of the substrate and filling an inside of the opening portion, and an outer insulating layer formed on the inner insulating layer.