Silicon Pressure Sensor Encapsulation with Flexible Sealing Pad
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Solution Overview
Problem
The existing encapsulation structures for silicon pressure sensors are complex and costly, making them unsuitable for batch production and applications involving corrosive media, as they require silicon oil and convoluted diaphragms for pressure transfer, which complicates the manufacturing process and increases costs.
Innovation Solution
A simplified encapsulation structure featuring a case and stem with a cavity, using a flexible sealing pad and conductive adhesive or layers to connect the pressure-sensitive silicon chip to the external circuit, eliminating the need for silicon oil and convoluted diaphragms, and incorporating a backup washer for enhanced overloading protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon oil and convoluted diaphragm are used for pressure transfer in corrosive media, then the silicon chip is protected from corrosion, but the structure and manufacturing process become complicated and cost increases
Solution Approach 1:
The patent removes the convoluted diaphragm and silicon oil from the encapsulation structure, replacing them with a simplified flat diaphragm design that directly transfers pressure to the silicon chip without requiring corrosion protection barriers, thus eliminating structural complexity while maintaining functionality
Solution Approach 2:
The patent employs a flat diaphragm made from inexpensive materials that can withstand corrosion without requiring expensive protective barriers like convoluted diaphragms and silicon oil, achieving cost reduction while maintaining adequate protection
2Reliability
If silicon oil and convoluted diaphragm are used for pressure transfer, then corrosion protection is achieved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent eliminates the silicon oil filling and convoluted diaphragm assembly steps from the manufacturing process, replacing them with a simple flat diaphragm that can be directly installed, significantly reducing manufacturing complexity and cost
Solution Approach 2:
The flat diaphragm is designed as a simple, inexpensive component that replaces expensive and complex corrosion protection systems, making the manufacturing process more economical and easier to execute
3Stability of the object's composition
If rigid encapsulation structure is used, then structural stability is achieved, but stress is applied to the silicon chip
Solution Approach 1:
The patent introduces a flexible flat diaphragm that can deform under pressure to absorb stress, preventing rigid stress transmission to the silicon chip while maintaining the overall structural stability of the encapsulation
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 solution significantly reduces material and process costs, simplifies the manufacturing process, and enhances the silicon pressure sensor's ability to withstand overloading pressures by up to ten times, while providing standard signal output and protecting the chip from rigid encapsulation stress.
Implementation Method 1
the bonding pad of the silicon chip is connected to the external circuit through the case
Implementation Method 2
The sealing pad is made of flexible material which keeps the pressure sensing chip floating in the ceramic space so as to protect from rigid encapsulation stress
Implementation Method 3
There is backup washer with certain thickness on top of pressure sensing chip or at the bottom of the case so as to protect the pressure sensing chip from being destroyed
Implementation Method 4
A simplified encapsulation structure featuring a case and stem with a cavity, using a flexible sealing pad and conductive adhesive or layers to connect the pressure-sensitive silicon chip to the external circuit
Data Source
AI summary
An encapsulation structure for silicon pressure sensor including a case and a stem is proposed. The case and the stem are connected with a cavity therebetween. A sealing pad and a pressure sensitive silicon chip are provided in the said cavity. The sealing pad is placed under the silicon chip and the silicon chip is connected to the external circuit through the bonding pad. This invention, with the anti-overloading ability, simplifies the encapsulation structure and manufacturing process which greatly reduces the cost of material and process.