Stacked Semiconductor Device With Diffusion Prevention Film
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Solution Overview
Problem
Conventional techniques face challenges in accurately controlling hydrogen concentration in pixel and peripheral circuit portions during the manufacturing of image sensors by stacking semiconductor substrates, leading to deteriorated reliability of fine transistors and image quality due to homogenization of hydrogen concentration during heat treatment.
Innovation Solution
A semiconductor device is developed with a diffusion prevention film inserted between the interfaces of stacked semiconductor substrates to prevent hydrogen diffusion, using a silicon nitride film as the diffusion prevention film and an atom supply film to terminate dangling bonds, thereby maintaining transistor reliability and improving signal output characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hydrogen is supplied to the entire semiconductor substrate including pixel portion and peripheral circuit portion, then the dark current on the photodiode surface is reduced, but the NBTI of fine transistors in the peripheral circuit portion deteriorates due to excessive hydrogen
Solution Approach 1:
The patent divides the semiconductor substrate into two distinct regions: a pixel portion and a peripheral circuit portion. By segmenting the substrate, the invention enables different hydrogen concentrations to be applied to each region, allowing dark current reduction in the pixel portion without excessive hydrogen accumulation in the peripheral circuit portion that would harm NBTI.
Solution Approach 2:
The patent implements local quality control by creating a hydrogen concentration gradient across different regions of the semiconductor substrate. The pixel portion receives higher hydrogen concentration to reduce dark current, while the peripheral circuit portion receives lower hydrogen concentration to maintain NBTI reliability. This is achieved through controlled hydrogen supply methods that target specific regions.
2Object-affected harmful factors
If the sinter process is used to control hydrogen concentration in different regions, then the pixel characteristic is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-forming a passivation film with non-uniform hydrogen concentration before the sintering process. This preliminary structuring of hydrogen distribution in the passivation film allows for more controlled and predictable hydrogen release during subsequent processing, reducing the complexity of real-time hydrogen concentration control during manufacturing.
3Adaptability or versatility
If multiple semiconductor chips are stacked to form image sensors, then the functionality is enhanced, but the hydrogen concentration homogenization during heat treatment deteriorates the reliability of fine transistors
Solution Approach 1:
The patent extends the segmentation principle to stacked semiconductor chips by introducing diffusion prevention films at the interfaces between chips. This segmentation isolates the hydrogen environments of different chips, preventing hydrogen concentration homogenization during heat treatment while maintaining the functional benefits of the stacked configuration.
Solution Approach 2:
The patent introduces diffusion prevention films as intermediary layers between stacked semiconductor chips. These intermediary films act as barriers that control hydrogen diffusion between chips during heat treatment, preventing harmful hydrogen homogenization while allowing the stacked structure to provide enhanced functionality.
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 effectively reduces interface states in the pixel portion while maintaining transistor reliability, enhancing image quality and signal output characteristics without excessive hydrogen concentration in the peripheral circuit.
Implementation Method 1
a diffusion prevention film that prevents diffusion of a dangling bond terminating atom used for reducing interface state of the first semiconductor substrate and the second semiconductor substrate
Implementation Method 2
atoms of hydrogen or fluorine have been used to terminate the dangling bonds at the device interface
Data Source
AI summary
The present technique relates to a semiconductor device and an electronic appliance in which the reliability of the fine transistor can be maintained while the signal output characteristic is improved in a device formed by stacking semiconductor substrates.The semiconductor device includes a first semiconductor substrate, a second semiconductor substrate providing a function different from a function provided by the first semiconductor substrate, and a diffusion prevention film that prevents diffusion of a dangling bond terminating atom used for reducing the interface state of the first semiconductor substrate and the second semiconductor substrate, wherein at least two semiconductor substrates are stacked and the semiconductor substrates are electrically connected to each other, and the first semiconductor substrate and the second semiconductor substrate are stacked with the diffusion prevention film inserted between an interface of the first semiconductor substrate and an interface of the second semiconductor substrate.