Semiconductor Package Miniaturization via Enclosing Frame Adhesion
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Solution Overview
Problem
The existing semiconductor package structure that fully encloses the imaging element in a sealed void, formed by a wiring board, enclosing frame, and glass cap, makes it difficult to apply to miniaturized camera modules due to size constraints.
Innovation Solution
A semiconductor package design featuring a wiring board, an imaging element mounted on it, and an enclosing frame with a basal and adhesion portion, where a cap is adhered to the adhesion portion, and a molding resin seals the exposed components, allowing for miniaturization by reducing the wiring board size and supporting the enclosing frame without enlarging the package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the imaging element is entirely accommodated in a sealed void formed by the wiring board, enclosing frame, and glass cap, then the imaging element is protected from dust and contaminants, but the semiconductor package size increases making it difficult to apply to miniaturized camera modules
Solution Approach 1:
The patent divides the protection function into two separate structures: (1) a sealing structure using the enclosing frame with adhesion portion and cap to protect the imaging element's light reception surface, and (2) a molding resin structure to protect the wiring board and other components. This segmentation allows each structure to be optimized independently, reducing overall package size while maintaining protection.
Solution Approach 2:
The enclosing frame extends in the thickness direction (vertical dimension) rather than requiring lateral expansion. The adhesion portion projects downward from the cap's lower surface, creating protection in the vertical dimension. This dimensional approach allows compact lateral footprint while maintaining adequate protection volume.
2Strength
If the enclosing frame is designed with a wide adhesion portion to improve bonding strength, then the cap is securely attached, but the package width increases
Solution Approach 1:
The adhesion portion extends primarily in the thickness direction (vertical dimension) with a projection distance of 0.01 to 0.05 times the outer diameter of the cap, rather than extending laterally. This vertical extension provides adequate bonding strength without increasing the package's lateral footprint, resolving the contradiction between bonding strength and package width.
Solution Approach 2:
The adhesion portion is strategically positioned at the periphery of the cap's lower surface, concentrating the bonding function at critical locations. The width of the adhesion portion is optimized to provide sufficient bonding area without excessive lateral extension, achieving strong bonding with minimal width increase.
3Volume of moving object
If the wiring board size is reduced to enable miniaturization, then the camera module can be smaller, but the enclosing frame may become unstable or difficult to support
Solution Approach 1:
The adhesion portion is designed with optimized dimensions (width of 0.05 to 0.1 times the outer diameter of the cap, and projection distance of 0.01 to 0.05 times the outer diameter) to provide sufficient bonding strength beforehand. This preliminary design ensures that the enclosing frame remains stable even when the wiring board size is reduced, as the adhesion portion provides adequate support without requiring a larger wiring board.
4Length of stationary object
If the adhesion portion is made thinner to reduce package height, then the package can be more compact, but the bonding strength between cap and enclosing frame decreases
Solution Approach 1:
The adhesion portion's dimensions are locally optimized with specific width (0.05 to 0.1 times the cap's outer diameter) and projection distance (0.01 to 0.05 times the cap's outer diameter) ratios. This localized optimization provides sufficient bonding strength while keeping the adhesion portion thin, thereby reducing overall package height without sacrificing bonding strength.
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 design enables miniaturization of the semiconductor package, reduces thermal stress through thickened adhesive, and improves yield by adjusting the air gap and preventing defects like scratches and foreign matter on the cap.
Implementation Method 1
A cap 50 is adhered by an adhesive agent 40 to an upper surface 32A of the adhesion portion 32
Implementation Method 2
A molding resin 60 contacts a lower surface 32B of the adhesion portion 32 and seals the electronic component 20 and the wiring board 10 that are exposed from the enclosing frame 30
Implementation Method 3
reduces thermal stress through thickened adhesive
Data Source
AI summary
A semiconductor package includes a wiring board, an electronic component mounted on the wiring board, and an enclosing frame arranged on an upper surface of the electronic component. The enclosing frame includes a basal portion, which has the form of a closed frame and extends along the upper surface of the electronic component, and an adhesion portion, which is wider than the basal portion and is arranged on the upper surface of the basal portion. A cap is adhered to an upper surface of the adhesion portion. A molding resin contacts a lower surface of the adhesion portion and seals the electronic component and the wiring board that are exposed from the enclosing frame.