Semiconductor Sensor Insulator Wall for Thickness Control
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Solution Overview
Problem
The conventional semiconductor physical quantity sensor faces challenges in controlling the thickness of the insulator, which affects detection accuracy due to thermal processes, leading to irregularities and reduced precision in capacitance changes.
Innovation Solution
A semiconductor physical quantity sensor design featuring a silicon oxide or nitride insulator with a wall portion that includes projections to define a space between the insulator and the electrode, ensuring a consistent thickness and preventing irregularities, thereby enhancing detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulator is provided over the electrode and deformed by thermal process to prevent ridge portions, then short circuit prevention is improved, but insulator thickness control deteriorates
Solution Approach 1:
The insulator thickness is controlled at the preliminary stage before thermal process by adjusting the insulator formation conditions (such as oxidation time, temperature, or deposition parameters). This preliminary control ensures that even after thermal deformation, the final thickness remains within the required range for accurate detection.
Solution Approach 2:
The invention changes the parameters of the insulator formation process (such as oxidation time, temperature, pressure, or material composition) to achieve precise thickness control. By optimizing these parameters, the insulator maintains consistent thickness despite subsequent thermal processing, thereby resolving the contradiction between reliability and manufacturing precision.
2Manufacturing precision
If insulator thickness cannot be controlled, then detection accuracy deteriorates
Solution Approach 1:
The invention implements feedback control by measuring the insulator thickness after formation and adjusting the formation conditions accordingly. This closed-loop approach ensures that the insulator thickness is precisely controlled within a narrow range, directly improving detection accuracy by eliminating thickness variations that would cause measurement errors.
Solution Approach 2:
By precisely controlling the parameters of insulator formation (oxidation time, temperature, pressure, material composition), the invention achieves consistent insulator thickness. This parameter control directly addresses the contradiction by ensuring that manufacturing precision is maintained at a level sufficient for high detection accuracy.
3Shape
If wall portion is formed between insulator and electrode, then space definition is improved, but device complexity increases
Solution Approach 1:
The invention merges the wall portion formation with the insulator formation process. The insulator itself is shaped to include the wall portion that defines the space between the electrode and diaphragm. This integration reduces device complexity by combining multiple functions (insulation and space definition) into a single structural element rather than adding separate components.
Solution Approach 2:
The insulator is designed with local quality variations, where specific regions of the insulator form wall portions with different geometries to define the space. This localized structuring achieves precise space definition without requiring the entire device structure to be complex, as only specific local regions of the insulator are shaped to create walls.
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 design improves detection accuracy by maintaining a consistent distance between the electrode and diaphragm, inhibiting external interference, and allowing for precise capacitance changes detection, even under thermal stress.
Implementation Method 1
the diaphragm bends in accordance with a physical quantity applied from the outside to change the capacitance of the semiconductor physical quantity sensor, and thus the semiconductor physical sensor is able to detect a change in the physical quantity by detecting the change in the capacitance
Data Source
AI summary
A semiconductor physical quantity sensor includes: a first base material; an electrode formed on the first base material; a diaphragm which bends in accordance with a physical quantity applied from the outside; a second base material fixed to the first base material and supporting the diaphragm such that the diaphragm is opposed to the electrode with a space (S) in between; and an insulator formed on a surface on the first base material side of the diaphragm. Moreover, a wall portion to define the space (S) is formed between the insulator and the electrode.