Semiconductor Pressure Sensor with Integrated Circuit and Perpendicular Lead-in
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Solution Overview
Problem
Existing pressure sensors face issues with reliability, long-term stability, and size due to fluid disturbance affecting the circuit, complex structure, high cost, and increased leakage risk due to separate air and fluid lead-in holes and lack of integration of data processing circuits.
Innovation Solution
A pressure sensor with integrated data processing circuit on the chip, where the air lead-in hole is connected to the inner cavity and the pressure lead-in hole is perpendicular, reducing the risk of fluid disturbance and leakage, and using an injection molding process for housing and lead frame integration, with gold wire bonding for electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate air and pressure lead-in holes are used, then fluid lead-in is achieved, but fluid disturbance affects the circuit and reliability is reduced
Solution Approach 1:
The patent extracts the harmful factor (fluid disturbance) from the sensor circuit area by routing the pressure lead-in hole to communicate with the back cavity of the sensor chip, separating the fluid path from the front circuit area. This extraction principle eliminates the harmful interaction between measured fluid and front surface circuits while maintaining pressure measurement functionality.
Solution Approach 2:
The patent introduces an intermediary structure (back cavity and lead frame) to mediate between the pressure lead-in hole and the sensor chip. The back cavity serves as an intermediate chamber that receives pressure from the lead-in hole and transmits it to the sensor chip's back surface, preventing direct fluid contact with front circuits while enabling pressure transmission.
2Device complexity
If data processing circuit is integrated on the chip, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent merges the data processing circuit with the sensor chip into a single integrated unit. The processing circuit is directly formed on the sensor chip substrate, eliminating the need for separate discrete circuits and reducing overall device complexity. This integration combines sensing and processing functions into one component.
3Strength
If convex cylindrical holes are used for lead-in, then fluid lead-in is achieved, but sensor size increases and intensity is reduced
Solution Approach 1:
The patent changes the dimensional approach of the lead-in hole from a convex cylindrical structure extending outward to a perpendicular hole penetrating the housing top surface. This dimensional reorientation allows the pressure lead-in hole to pass through the housing vertically, reducing the horizontal footprint and maintaining housing strength while enabling fluid access.
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 enhances reliability, stability, and accuracy while reducing sensor size and complexity by integrating the data processing circuit and ensuring effective sealing, thus minimizing the risk of electrical connection failures and fluid disturbance.
Implementation Method 1
The sensitive components have the piezoresistive effect, so, they have resistance variation, and the resistance variation are converted into a voltage and output through a Wheatstone bridge composed of the sensitive components.
Implementation Method 2
If a pressure is applied on the elastic film, the elastic film will be bent at a certain degree according to the intensity of pressure.
Implementation Method 3
the sensor chip and the lead frame are electrically connected in a gold wire bonding manner
Data Source
AI summary
A pressure sensor has a housing, an air lead-in hole, a pressure lead-in hole, an inner cavity, a sensor chip, a lead frame and a cover plate. One end of the air lead-in hole is in communication with the inner cavity of the housing, and the other end of the air lead-in hole is in communication with the air; the pressure lead-in hole is perpendicularly disposed at the center of the upper surface of the housing, two steps are disposed on the upper surface of the inner cavity, and a horizontal surface-mounted device surface is disposed on each of the steps. The center of the sensor chip is aligned with the centers of the pressure lead-in hole, and the lower end of the pressure lead-in holes are in communication with the cavity of the sensor chip.