Porous Support Ring for CMOS Image Sensor Package Sealing
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Solution Overview
Problem
The packaging structure for high-performance CMOS image sensing chips faces delamination issues due to pressure differences caused by thermal treatment, leading to reduced yield, as the existing air-tight sealing methods using non-air-permeable materials do not accommodate pressure changes effectively.
Innovation Solution
A chip packaging structure that includes a supporting member formed by stacking microstructures with pores, allowing for pressure equilibrium during thermal treatment, and an encapsulant that fills these pores to create a hermetic air cavity while preventing moisture ingress, using materials like polyurethane and glass fibers for the supporting member and epoxy for the encapsulant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hermetic packaging structure with non-air-permeable cover glass and dam is used, then the packaging provides good sealing and protection, but the internal pressure increases during thermal treatment processes causing delamination
Solution Approach 1:
The dam structure incorporates porous material that allows air permeability while maintaining the hermetic seal function. The porous structure enables pressure equalization between the internal cavity and external environment during thermal treatment, preventing delamination of the dam from the substrate while preserving the protective sealing function.
Solution Approach 2:
The packaging structure uses composite materials combining hermetic sealing layers with air-permeable porous layers in the dam. This composite construction allows simultaneous achievement of hermetic sealing for protection and controlled air permeability for pressure equalization during thermal processes.
2Object-affected harmful factors
If the packaging structure is made hermetic with non-air-permeable components, then protection against environmental factors is improved, but pressure difference during thermal treatment causes structural damage
Solution Approach 1:
The dam incorporates porous material that provides controlled air permeability to equalize pressure during thermal treatment, preventing structural damage while maintaining protection against environmental factors through the hermetic sealing layers.
Solution Approach 2:
The porous dam acts as an intermediary element between the hermetic sealing requirement and the pressure equalization need. It mediates between these two conflicting requirements by allowing controlled air passage while maintaining the overall hermetic seal structure.
3Ease of manufacture
If thermal treatment processes are applied to the packaged product, then manufacturing and assembly are facilitated, but the internal pressure increases causing delamination and reducing yield
Solution Approach 1:
The porous dam structure enables thermal treatment processes to be applied without causing delamination, as the porous material allows pressure equalization. This maintains high production yield while preserving the ease of manufacture benefits from thermal treatment processes.
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
The solution effectively balances internal pressure during thermal treatment, preventing delamination and ensuring the structural integrity and moisture protection of the chip packaging, thereby enhancing yield and reliability.
Implementation Method 1
the supporting member is formed by stacking a plurality of microstructures with each other, so that the supporting member has a plurality of pores
Data Source
AI summary
A chip packaging structure and a chip packaging method are provided. The chip packaging structure includes a first substrate, an image sensing chip, a supporting member, a second substrate, and an encapsulant. The image sensing chip is disposed on an upper surface of the first substrate, and the image sensing chip has an image sensing region. The supporting member is disposed on an upper surface of the image sensing chip and surrounds the image sensing region. The supporting member is formed by stacking microstructures with each other, so that the supporting member has pores. The second substrate is disposed on an upper surface of the supporting member, and the second substrate, the supporting member, and the image sensing chip define an air cavity. The encapsulant is attached to the upper surface of the first substrate and a side surface of the second substrate and filled into the pores.