Semiconductor Pressure Sensor Alignment Through Covered Silicon Substrates
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Solution Overview
Problem
Existing semiconductor pressure sensors face issues with contamination from foreign objects in alignment marks and compromised positioning accuracy due to exposed alignment marks, leading to decreased manufacturing stability and reliability.
Innovation Solution
A semiconductor pressure sensor design where a second silicon substrate covers the alignment mark and recessed portion on a first silicon substrate, allowing for improved positioning accuracy and reduced contamination risk, with the alignment mark detectable using an infrared camera even when covered.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the alignment mark is provided in an exposed state not covered by the second substrate, then the alignment mark is easily accessible for positioning, but foreign objects such as resist remain inside the recessed portion causing contamination and decreasing manufacturing stability
Solution Approach 1:
The alignment mark is extracted from the exposed state and positioned within the recessed portion that is covered by the second substrate. This removes the alignment mark from the harmful environment where foreign objects could contaminate it, while still allowing access during the manufacturing process before final assembly.
Solution Approach 2:
The alignment mark is prepared and positioned in the recessed portion of the first substrate before the second substrate is attached. This preliminary positioning ensures that the alignment mark is protected from contamination in subsequent manufacturing steps while maintaining its functionality for positioning operations.
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
This configuration enhances manufacturing stability and reliability by preventing contamination and improving positioning accuracy across the wafer, including central areas, without exposing the alignment mark.
Implementation Method 1
a second silicon substrate that is joined to the one main face of the first silicon substrate across an oxide film
Implementation Method 2
a step of detecting the alignment mark using an infrared camera
Data Source
AI summary
The present application provides a semiconductor pressure sensor having high manufacturing stability and high accuracy. A second silicon substrate is bonded across an oxide film to one main face of a first silicon substrate, in which a recessed portion that becomes a reference pressure chamber and an alignment mark are formed, whereby the first silicon substrate and the second silicon substrate are joined in a state wherein the recessed portion and the alignment mark are covered by the second silicon substrate. The alignment mark is detected using an infrared sensor, positioning is carried out using the alignment mark, and a gauge resistor, which is a pressure-sensitive element portion, is formed in a diaphragm formed in the second silicon substrate positioned above the recessed portion.