Image Sensor Package Structure for Warpage and Heat Control
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Solution Overview
Problem
Conventional semiconductor devices with a chip on board (COB) structure face issues with warpage due to differences in the coefficient of linear expansion between the image sensor and the substrate, leading to reduced image quality and limited arrangement areas for external terminals and peripheral components.
Innovation Solution
A semiconductor device configuration featuring a substrate with a recess and a plate-shaped member fixed to the substrate, where the image sensor is positioned on the front surface of the substrate, and a thermal conduction part is used to manage heat transfer, allowing for flexible placement of external terminals and peripheral components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the image sensor is directly bonded to the substrate via die-bond material in a COB structure, then the device structure is simple and manufacturing is easy, but warpage occurs due to difference in coefficient of linear expansion between the image sensor and substrate
Solution Approach 1:
A support substrate is introduced as an intermediary component between the image sensor and the substrate. This support substrate has a coefficient of linear expansion matched to the image sensor, serving as a mediator that prevents warpage while maintaining the simplicity of the COB structure. The support substrate bonds to the image sensor and provides mechanical support during assembly and operation.
Solution Approach 2:
The coefficient of linear expansion parameter is changed by selecting a support substrate material whose thermal expansion characteristics match those of the image sensor. This parameter matching prevents differential thermal expansion and the resulting warpage, while the support substrate maintains ease of manufacture through standard bonding processes.
2Manufacturing precision
If a frame-shaped substrate with metal plate is used to reduce warpage, then warpage control is improved, but the arrangement area for external terminals and peripheral components is limited
Solution Approach 1:
The support substrate is extracted as a separate, removable component rather than being integrated into the substrate structure. This allows the support substrate to provide warpage control while leaving the substrate surface fully available for mounting external terminals and peripheral components, thus resolving the space limitation issue.
Solution Approach 2:
The device is segmented into distinct functional components: the support substrate for mechanical support and warpage control, and the substrate for electrical connections and component mounting. This segmentation allows each component to perform its function optimally without interfering with the other's space requirements.
3Manufacturing precision
If the support substrate covers the entire back surface of the image sensor, then warpage control is maximized, but heat dissipation is reduced
Solution Approach 1:
The support substrate is designed with local quality variations: it provides full coverage and rigid support in regions where warpage control is critical, while having reduced coverage or different structural properties in regions where heat dissipation is prioritized. This localized approach optimizes both warpage control and thermal management.
Solution Approach 2:
The support substrate is designed as a thin, flexible structure that provides sufficient mechanical support for warpage control while allowing thermal energy to pass through. The thin film structure minimizes thermal resistance and enables heat to dissipate from the image sensor through the support substrate to the substrate below.
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 configuration effectively controls warpage and maintains image quality by reducing thermal expansion-induced stress and allowing for more flexible component placement.
Implementation Method 1
a thermal conduction part is used to manage heat transfer
Implementation Method 2
differences in the coefficient of linear expansion between the image sensor and the substrate causes the occurrence of warpage
Data Source
AI summary
In a semiconductor device, to enable control of the occurrence of warpage of a sensor chip serving as a semiconductor element and a change in the warpage as well as prevention of limitation on an arrangement area of an external terminal and a peripheral component. There is included a semiconductor element in which one plate surface side of a semiconductor substrate is set as a light-receiving side, a substrate part having a recess, the recess being open to face a front surface side that is the light-receiving side and positioning the semiconductor element on the front surface side, and a plate shaped member positioned in the recess in a state where the plate shaped member is fixed to the substrate part, the plate shaped member fixing the semiconductor element to one plate surface side and being provided via a gap on at least another plate surface side with respect to a surface forming the recess.