Image Pickup Device Substrate Thickness Gradient
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Solution Overview
Problem
Existing image pickup devices face challenges in reducing size and thickness without compromising the reliability and integrity of the semiconductor substrate, as thinner substrates are prone to deformation and cracking due to stress concentration during manufacturing processes like reflowing.
Innovation Solution
The design incorporates a transparent member, an image pickup element chip with a semiconductor substrate featuring a penetrating electrode, and a fixing member that surrounds the chip, with the thickness boundary within the fixing area, reducing the likelihood of deformation and cracking by distributing stress more evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the silicon substrate is reduced to form a penetrating electrode, then the size of the image pickup device is reduced, but the intensity and strength of the substrate are decreased, causing deformation and cracking of the image pickup element chip
Solution Approach 1:
The patent applies local quality by creating a thickness gradient in the semiconductor substrate, where the thickness varies from a first thickness in the first area to a second thickness in the second area. This localized variation in thickness allows the substrate to be thinner in certain regions (reducing overall device size) while maintaining adequate thickness in other regions (preserving strength and preventing deformation), thereby resolving the contradiction between size reduction and strength maintenance.
2Volume of moving object
If the thickness of the silicon substrate is reduced, then the size of the image pickup device is reduced, but the reliability is reduced due to increased likelihood of deformation and cracking
Solution Approach 1:
The patent implements local quality through a thickness gradient structure where different regions of the semiconductor substrate have different thicknesses. This allows the substrate to be thinner in regions where strength is less critical (maintaining small device size) while being thicker in regions where structural integrity is important (maintaining reliability), thus resolving the contradiction between size reduction and reliability maintenance.
3Ease of manufacture
If a space portion is expanded in the manufacturing process including heat processing, then the penetrating electrode can be formed, but stress concentration occurs at the portion where the thickness of the semiconductor substrate is small, causing deformation and cracking
Solution Approach 1:
The patent applies local quality by designing a thickness gradient in the semiconductor substrate, where the thickness varies across different regions. This localized thickness variation allows the substrate to accommodate the space portion expansion during manufacturing (enabling penetrating electrode formation) while maintaining adequate thickness in critical areas to prevent stress concentration, deformation, and cracking, thus resolving the contradiction between manufacturing ease and strength maintenance.
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 enhances the reliability of the image pickup device by minimizing the risk of semiconductor substrate deformation and cracking, allowing for larger-sized devices with improved strength and reduced manufacturing defects.
Implementation Method 1
an image pickup element chip 2 including a photodiode
Data Source
AI summary
An image pickup device includes a transparent member, an image pickup element chip including a photodiode, and a fixing member arranged around the image pickup element chip, a space being surrounded by the transparent member, the image pickup element chip, and the fixing member. The image pickup element chip includes a semiconductor substrate including a penetrating electrode penetrating through a first main face of the semiconductor substrate on a side of the transparent member and a second main face of the semiconductor substrate opposite the first main face. In an orthogonal projection with respect to the transparent member, the penetrating electrode is arranged in a fixing area corresponding to the fixing member, and a boundary with an area where the thickness of the semiconductor substrate is smaller than that of the semiconductor substrate in a first area corresponding to the space is arranged within the fixing area.