Imaging Sensor Pad Layout for Simpler Bottom-Side Mounting
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Solution Overview
Problem
Conventional imaging devices face difficulties in mounting due to the need for bonding wires on the light receiving surface of semiconductor chips, making it challenging to connect and integrate image sensor devices effectively.
Innovation Solution
The imaging device includes an imaging element with a light transmitting portion and pads on a different surface, connected via a wiring substrate with extended wiring and sealed by a sealing portion, allowing for simplified mounting and integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bonding wires are used to connect pads on the light receiving surface, then electrical connection is achieved, but mounting complexity increases and integration becomes difficult
Solution Approach 1:
The pad is moved from the light receiving surface (top surface) to the bottom surface of the semiconductor chip, changing the spatial dimension of the connection interface. This allows the pad to be accessible from the opposite side, enabling direct wiring substrate connection without requiring bonding wires to cross the light path or navigate complex routing on the front surface.
Solution Approach 2:
The bonding wire connection method is extracted and replaced by direct pad-to-wiring substrate connection. By removing the bonding wire intermediary and using the pad on the bottom surface directly for electrical connection, the mounting process is simplified while maintaining reliable electrical connectivity.
2Reliability
If pads are arranged on the light receiving surface for signal output, then electrical connection is established, but mounting process becomes complex requiring bonding wires
Solution Approach 1:
The pad position is shifted to the bottom surface, allowing the wiring substrate to be connected directly to the pad without requiring complex bonding wire processes. This dimensional change simplifies the manufacturing and mounting steps while ensuring reliable signal transmission from the imaging element to the external circuit.
3Ease of operation
If wiring is extended outside the imaging element, then connection ease is improved, but device structure becomes more complex
Solution Approach 1:
The pad is pre-positioned on the bottom surface of the semiconductor chip during chip fabrication, and the wiring substrate is designed with corresponding connection structures. This preliminary arrangement of the pad position and wiring layout enables direct connection without requiring additional complex structural elements or post-processing steps to extend wiring outside the imaging element.
Data Source
AI summary
An imaging device to which a simple mounting method can be applied is configured. The imaging device is provided with an imaging element, a wiring substrate, and a sealing portion. The imaging element is provided with an image pickup chip over which an light transmitting portion transmitting incident light is arranged and which generates an image signal on the basis of the incident light that has passed through the light transmitting portion, and a pad which is arranged on a bottom surface of the image pickup chip different from a surface on which the light transmitting portion is arranged, which the pad transmitting the generated image signal. The wiring substrate has wiring connected to the pad and extending to a region outside the imaging element, and has the imaging element arranged on a surface thereof. The sealing portion is arranged adjacent to a side surface which is a surface adjacent to the bottom surface of the imaging element, and seals the imaging element.