Semiconductor Device Moisture Control via Inert Atmosphere Bonding
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Solution Overview
Problem
Semiconductor devices with oxide semiconductors are prone to changes in electrical characteristics due to hydrogen-containing impurities like moisture, especially when an organic resin film is used as a planarization layer, which easily absorbs moisture, affecting the stability and reliability of the device.
Innovation Solution
Performing heat treatment on substrates with oxide semiconductors and organic resin films in a reduced pressure atmosphere and minimizing exposure to moisture, followed by bonding in a controlled inert gas environment with a dew point of -60°C or lower, to prevent moisture absorption and ensure stable electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an organic resin film is used as a planarization film to easily form a flat surface, then the ease of manufacture is improved, but the film absorbs moisture which changes the electrical characteristics of the transistor
Solution Approach 1:
The patent applies inert atmosphere by performing heat treatment in a reduced pressure atmosphere (vacuum) and conducting bonding operations in a controlled inert gas environment with dew point of -60°C or lower. This prevents moisture absorption by the organic resin film during manufacturing, thereby maintaining stable electrical characteristics of the oxide semiconductor transistor while still utilizing the organic resin film for planarization.
Solution Approach 2:
The patent applies preliminary action by performing heat treatment in a reduced pressure atmosphere before bonding to remove moisture from the organic resin film in advance. This preliminary moisture removal prevents subsequent moisture absorption that would otherwise change the electrical characteristics of the transistor, ensuring reliability while maintaining the manufacturing advantages of organic resin films.
2Manufacturing precision
If heat treatment is performed in a reduced pressure atmosphere to remove moisture, then the purity of the oxide semiconductor is improved, but the process complexity increases
Solution Approach 1:
The patent merges the heat treatment process with the moisture removal process by performing both operations simultaneously in a reduced pressure atmosphere. This combined approach achieves high purity oxide semiconductor while consolidating process steps, thereby reducing overall process complexity compared to separate treatment stages.
Solution Approach 2:
The patent uses reduced pressure atmosphere (vacuum) as an inert environment that simultaneously achieves moisture removal and prevents recontamination. This single inert atmosphere approach accomplishes purity improvement without requiring multiple process steps, thereby limiting the increase in device complexity.
3Reliability
If bonding is performed in a controlled inert gas environment with low dew point to prevent moisture absorption, then the reliability is improved, but the manufacturing time increases
Solution Approach 1:
The patent maintains continuous control of the inert gas environment throughout the bonding process, ensuring that the low dew point condition is sustained without interruption. This continuous control prevents moisture absorption during the entire bonding operation, achieving high reliability while minimizing idle time that would occur with repeated atmosphere adjustments.
Solution Approach 2:
The patent uses a controlled inert gas environment with dew point of -60°C or lower during bonding to prevent moisture absorption. By establishing this controlled environment once and maintaining it throughout the bonding process, the patent achieves improved reliability without requiring multiple atmosphere changes that would increase manufacturing time.
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 method results in semiconductor devices with stable electrical characteristics and high reliability by minimizing moisture absorption, thereby reducing impurity-induced changes in transistor performance.
Implementation Method 1
Heat treatment is performed on a first substrate provided with an organic resin film over a transistor including an oxide semiconductor in a reduced pressure atmosphere
Implementation Method 2
Heat treatment is performed on a first substrate provided with an organic resin film over a transistor including an oxide semiconductor in a reduced pressure atmosphere
Implementation Method 3
applying a sealant to one of the first substrate and a second substrate which serves as an opposite substrate; disposing a surface of the first substrate over which the transistor and the organic resin film are provided and the second substrate facing each other, and bonding them to each other
Data Source
AI summary
A semiconductor device including an oxide semiconductor and an organic resin film is manufactured in the following manner. Heat treatment is performed on a first substrate provided with an organic resin film over a transistor including an oxide semiconductor in a reduced pressure atmosphere; handling of the first substrate is performed in an atmosphere containing moisture as little as possible in an inert gas (e.g., nitrogen) atmosphere with a dew point of lower than or equal to −60° C., preferably with a dew point of lower than or equal to −75° C. without exposing the first substrate after the heat treatment to the air; and then, the first substrate is bonded to a second substrate that serves as an opposite substrate.