Image Sensor Packaging Thickness Reduction via Substrate Segmentation
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Solution Overview
Problem
The existing wafer-level packaging technology for image sensing chips results in a thick packaging structure that fails to meet the market demand for thinner electronic products, and attempts to reduce thickness compromise the protection and performance of the sensing region.
Innovation Solution
A two-layered upper cover substrate structure is formed by attaching a first substrate with a thickness of 300 μm to 500 μm to a second substrate with a thickness of 100 μm to 200 μm using an adhesive layer, where the second substrate is retained to protect the sensing region, allowing the first substrate to be removed post-packaging, thereby reducing the package thickness without affecting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an upper cover substrate with thickness of 400 μm is used to protect the sensing region, then the protection performance is improved, but the overall package thickness increases and cannot meet the market demand for thinner electronic products
Solution Approach 1:
The upper cover substrate is divided into two separate substrates: a first substrate (300-500 μm thick) that provides protection during packaging and is subsequently removed, and a second substrate (100-200 μm thick) that remains to protect the sensing region. This segmentation allows the protective function to be separated from the final thickness constraint, enabling thin packaging while maintaining protection during critical processes.
Solution Approach 2:
The first substrate provides preliminary protection to the sensing region during the packaging process before being removed. This preliminary protective action allows the sensing region to be protected when needed (during packaging) while enabling thin final packaging structure, as the first substrate is temporarily used and then discarded.
2Length of stationary object
If the upper cover substrate thickness is reduced to decrease package thickness, then the package thickness requirement is met, but the sensing region becomes vulnerable to pollution and damage
Solution Approach 1:
The protective function is segmented between two substrates with different roles and thicknesses. The first substrate (thicker) provides robust protection during packaging, while the second substrate (thinner) provides sufficient protection in the final package. This segmentation allows meeting thickness requirements while maintaining protection through the first substrate's temporary presence.
Solution Approach 2:
The thickness parameter of the upper cover structure is changed from a single thick substrate (400 μm) to a two-substrate configuration where the remaining second substrate is much thinner (100-200 μm). The first substrate compensates for the reduced thickness during packaging, enabling the final structure to be thin while maintaining protection during the process.
3Reliability
If a single thick upper cover substrate is used, then the sensing region is well protected during packaging, but the overall device complexity increases and cannot be miniaturized further
Solution Approach 1:
The single thick substrate is segmented into two substrates with different functions. The first substrate handles the protection during packaging, while the second substrate provides the final protective layer. This segmentation actually simplifies the overall design by allowing each substrate to be optimized for its specific role, enabling miniaturization while maintaining protection.
Solution Approach 2:
The first substrate is discarded after serving its protective purpose during packaging. This temporary use and subsequent removal of the first substrate reduces the final package complexity and thickness while having provided necessary protection during the critical packaging phase.
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 enables a reduction in packaging thickness without compromising the protection of the sensing region, ensuring the structural integrity and transparency of the second substrate, thus meeting the demand for thinner electronic products while maintaining performance.
Implementation Method 1
attaching either surface of the first substrate with the first surface of the second substrate with an adhesive layer
Data Source
AI summary
A method for forming an image sensor package and an image sensor package are provided. The method includes: providing a first substrate and a second substrate which includes a first surface and a second surface opposite to the first surface, and attaching either surface of the first substrate with the first surface of the second substrate with an adhesive layer; forming a groove at the second surface of the second substrate; providing a base which includes a first surface and a second surface opposite to the first surface, where the first surface of the base is provided with a sensing region and multiple contact pads; and attaching the second surface of the second substrate with the first surface of the base, where a cavity is formed between the groove and the base, and the sensing region is located within the cavity.