Stacked Semiconductor Substrates with Concave Electrodes for Global Shutter Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In CMOS type solid-state image sensors with global shutter function, the integration of photoelectric converters and storage capacitors on the same substrate leads to increased wafer area occupation and signal quality deterioration due to light leakage and storage capacitance noise during the standby period before signal readout.
Innovation Solution
A semiconductor device comprising a first semiconductor substrate with a pixel array and a second semiconductor substrate with a read-out circuit, where concave portions with electrodes are formed on both substrates for electrical connection, allowing for inspection and filling with a filler to prevent damage during probe needle inspection, enabling efficient electrical connection and improved signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If photoelectric converters and storage capacitors are integrated on the same substrate to achieve global shutter function, then simultaneous charge accumulation capability is improved, but wafer area occupation increases
Solution Approach 1:
The patent divides the solid-state image sensor into two separate substrates: a first substrate containing the photoelectric converters and a second substrate containing the storage capacitors and read-out circuits. These substrates are bonded together through connection portions, allowing the global shutter function to be achieved while reducing the area occupation on a single wafer.
2Adaptability or versatility
If storage capacitors are used to accumulate signal charges during standby period, then simultaneous charge accumulation is enabled, but signal quality deteriorates due to light leakage and storage capacitance noise
Solution Approach 1:
The patent extracts the storage capacitor function from the photoelectric converter substrate and places it on a separate second substrate. This separation reduces the harmful effects of light leakage and storage capacitance noise on signal quality while maintaining the capability for simultaneous charge accumulation across all pixels.
3Measurement precision
If probe needle inspection is performed on electrode surfaces, then operational verification is achieved, but needle impressions cause deformation or disconnection risk
Solution Approach 1:
The patent forms concave portions in the connection surfaces before bonding the substrates. These concave portions receive the probe needle impressions during inspection, preventing the impressions from affecting the flatness and electrical connection quality between substrates. This preliminary structural preparation allows accurate inspection while maintaining connection integrity.
Data Source
AI summary
A semiconductor device includes a first semiconductor substrate and a second semiconductor substrate. The first semiconductor substrate and the second semiconductor substrate are electrically connected to each other in a state in which a first connection surface of the first semiconductor substrate and a second connection surface of the second semiconductor substrate face each other. A concave portion is formed in at least one of the first connection surface and the second connection surface. An electrode, which is electrically connected to a portion of wirings included in a wiring layer provided in the first semiconductor substrate or the second semiconductor substrate in which the concave portion is formed and is capable of being electrically connected to an outside, is formed in an inside of the concave portion.