Solid-State Imaging Device Dummy Connectors for Bonding Strength
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Solution Overview
Problem
Existing solid-state imaging devices face challenges in achieving uniform exposure timing across all pixels due to the sequential readout method, leading to variations in image quality and increased complexity in manufacturing three-dimensional semiconductor structures with bonded wafers.
Innovation Solution
A solid-state imaging device is developed where a first substrate with photoelectric conversion units is bonded to a second substrate with an output circuit via connectors, with dummy connectors arranged in non-connector regions to enhance mechanical strength and reduce pressure during bonding, allowing for improved uniformity and reduced distortion during dicing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If connectors are arranged only in necessary regions for electrical connection, then device complexity is reduced, but mechanical strength during bonding is insufficient causing substrate distortion and cracking
Solution Approach 1:
The connector arrangement is segmented into two types: real connectors in active regions for electrical connection, and dummy connectors in inactive regions for mechanical support. This segmentation allows each type to fulfill its specific function without interfering with the other, resolving the contradiction between mechanical strength and device complexity.
Solution Approach 2:
Dummy connectors are used as sacrificial elements that provide mechanical strength during the bonding process but are later removed through dicing. These temporary structures serve their purpose during manufacturing and are discarded in the final product, allowing mechanical reinforcement without permanent complexity.
2Ease of manufacture
If wafer bonding is performed without sufficient mechanical support, then manufacturing process is simplified, but substrate distortion and cracking occur during dicing
Solution Approach 1:
Dummy connectors are formed on the substrates before the bonding process to provide preliminary mechanical support. This preliminary action ensures that the substrates maintain their shape and position during bonding and subsequent dicing, preventing distortion and cracking while keeping the manufacturing process relatively simple.
3Ease of operation
If pressure is applied uniformly during wafer bonding, then bonding is easier to control, but distortion occurs in regions without adequate support
Solution Approach 1:
Dummy connectors are strategically placed in inactive regions where mechanical support is needed but electrical connection is not required. This local quality approach provides targeted support exactly where needed during bonding and dicing, maintaining substrate shape uniformity without interfering with the bonding control in active regions.
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
The solution ensures uniform exposure timing across all pixels, enhances mechanical strength for chip manufacturing, and reduces the risk of cracking and chipping during dicing, resulting in improved image quality and manufacturing efficiency.
Implementation Method 1
a first substrate formed on a first semiconductor wafer and a second substrate formed on a second semiconductor wafer are bonded via connector that electrically connects the substrates. The first substrate includes photoelectric conversion units.
Data Source
AI summary
A solid-state imaging device is a solid-state imaging device in which a first substrate formed on a first semiconductor wafer and a second substrate formed on a second semiconductor wafer are bonded via connect that electrically connects the substrates, wherein the first substrate includes photoelectric conversion units, the second substrate includes an output circuit that acquires a signal generated by the photoelectric conversion unit via the connector and outputs the signal, and dummy connectors that support the first and second bonded substrates are further arranged in a substrate region in which the connectors are not arranged in a substrate region of at least one of the first substrate and the second substrate.